#include "llvm/Transforms/Scalar.h"
#include "InstCombine.h"
#include "llvm/IntrinsicInst.h"
-#include "llvm/LLVMContext.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/GlobalVariable.h"
-#include "llvm/Operator.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Target/TargetData.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Support/CallSite.h"
+#include "llvm/Support/CFG.h"
#include "llvm/Support/Debug.h"
-#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
-#include "llvm/Support/MathExtras.h"
#include "llvm/Support/PatternMatch.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/STLExtras.h"
#include <algorithm>
#include <climits>
using namespace llvm;
STATISTIC(NumCombined , "Number of insts combined");
STATISTIC(NumConstProp, "Number of constant folds");
STATISTIC(NumDeadInst , "Number of dead inst eliminated");
-STATISTIC(NumDeadStore, "Number of dead stores eliminated");
STATISTIC(NumSunkInst , "Number of instructions sunk");
}
-// isOnlyUse - Return true if this instruction will be deleted if we stop using
-// it.
-static bool isOnlyUse(Value *V) {
- return V->hasOneUse() || isa<Constant>(V);
-}
-
-// getPromotedType - Return the specified type promoted as it would be to pass
-// though a va_arg area...
-static const Type *getPromotedType(const Type *Ty) {
- if (const IntegerType* ITy = dyn_cast<IntegerType>(Ty)) {
- if (ITy->getBitWidth() < 32)
- return Type::getInt32Ty(Ty->getContext());
- }
- return Ty;
-}
-
/// ShouldChangeType - Return true if it is desirable to convert a computation
/// from 'From' to 'To'. We don't want to convert from a legal to an illegal
/// type for example, or from a smaller to a larger illegal type.
return true;
}
-/// getBitCastOperand - If the specified operand is a CastInst, a constant
-/// expression bitcast, or a GetElementPtrInst with all zero indices, return the
-/// operand value, otherwise return null.
-static Value *getBitCastOperand(Value *V) {
- if (Operator *O = dyn_cast<Operator>(V)) {
- if (O->getOpcode() == Instruction::BitCast)
- return O->getOperand(0);
- if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
- if (GEP->hasAllZeroIndices())
- return GEP->getPointerOperand();
- }
- return 0;
-}
-
-
// SimplifyCommutative - This performs a few simplifications for commutative
// operators:
Changed = !I.swapOperands();
if (!I.isAssociative()) return Changed;
+
Instruction::BinaryOps Opcode = I.getOpcode();
if (BinaryOperator *Op = dyn_cast<BinaryOperator>(I.getOperand(0)))
if (Op->getOpcode() == Opcode && isa<Constant>(Op->getOperand(1))) {
I.setOperand(0, Op->getOperand(0));
I.setOperand(1, Folded);
return true;
- } else if (BinaryOperator *Op1=dyn_cast<BinaryOperator>(I.getOperand(1)))
+ }
+
+ if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(I.getOperand(1)))
if (Op1->getOpcode() == Opcode && isa<Constant>(Op1->getOperand(1)) &&
- isOnlyUse(Op) && isOnlyUse(Op1)) {
+ Op->hasOneUse() && Op1->hasOneUse()) {
Constant *C1 = cast<Constant>(Op->getOperand(1));
Constant *C2 = cast<Constant>(Op1->getOperand(1));
return ConstantExpr::getNeg(C);
if (ConstantVector *C = dyn_cast<ConstantVector>(V))
- if (C->getType()->getElementType()->isInteger())
+ if (C->getType()->getElementType()->isIntegerTy())
return ConstantExpr::getNeg(C);
return 0;
// instruction if the LHS is a constant negative zero (which is the 'negate'
// form).
//
-static inline Value *dyn_castFNegVal(Value *V) {
+Value *InstCombiner::dyn_castFNegVal(Value *V) const {
if (BinaryOperator::isFNeg(V))
return BinaryOperator::getFNegArgument(V);
return ConstantExpr::getFNeg(C);
if (ConstantVector *C = dyn_cast<ConstantVector>(V))
- if (C->getType()->getElementType()->isFloatingPoint())
+ if (C->getType()->getElementType()->isFloatingPointTy())
return ConstantExpr::getFNeg(C);
return 0;
}
-/// MatchSelectPattern - Pattern match integer [SU]MIN, [SU]MAX, and ABS idioms,
-/// returning the kind and providing the out parameter results if we
-/// successfully match.
-static SelectPatternFlavor
-MatchSelectPattern(Value *V, Value *&LHS, Value *&RHS) {
- SelectInst *SI = dyn_cast<SelectInst>(V);
- if (SI == 0) return SPF_UNKNOWN;
-
- ICmpInst *ICI = dyn_cast<ICmpInst>(SI->getCondition());
- if (ICI == 0) return SPF_UNKNOWN;
-
- LHS = ICI->getOperand(0);
- RHS = ICI->getOperand(1);
-
- // (icmp X, Y) ? X : Y
- if (SI->getTrueValue() == ICI->getOperand(0) &&
- SI->getFalseValue() == ICI->getOperand(1)) {
- switch (ICI->getPredicate()) {
- default: return SPF_UNKNOWN; // Equality.
- case ICmpInst::ICMP_UGT:
- case ICmpInst::ICMP_UGE: return SPF_UMAX;
- case ICmpInst::ICMP_SGT:
- case ICmpInst::ICMP_SGE: return SPF_SMAX;
- case ICmpInst::ICMP_ULT:
- case ICmpInst::ICMP_ULE: return SPF_UMIN;
- case ICmpInst::ICMP_SLT:
- case ICmpInst::ICMP_SLE: return SPF_SMIN;
- }
- }
-
- // (icmp X, Y) ? Y : X
- if (SI->getTrueValue() == ICI->getOperand(1) &&
- SI->getFalseValue() == ICI->getOperand(0)) {
- switch (ICI->getPredicate()) {
- default: return SPF_UNKNOWN; // Equality.
- case ICmpInst::ICMP_UGT:
- case ICmpInst::ICMP_UGE: return SPF_UMIN;
- case ICmpInst::ICMP_SGT:
- case ICmpInst::ICMP_SGE: return SPF_SMIN;
- case ICmpInst::ICMP_ULT:
- case ICmpInst::ICMP_ULE: return SPF_UMAX;
- case ICmpInst::ICMP_SLT:
- case ICmpInst::ICMP_SLE: return SPF_SMAX;
- }
- }
-
- // TODO: (X > 4) ? X : 5 --> (X >= 5) ? X : 5 --> MAX(X, 5)
-
- return SPF_UNKNOWN;
-}
-
-/// isFreeToInvert - Return true if the specified value is free to invert (apply
-/// ~ to). This happens in cases where the ~ can be eliminated.
-static inline bool isFreeToInvert(Value *V) {
- // ~(~(X)) -> X.
- if (BinaryOperator::isNot(V))
- return true;
-
- // Constants can be considered to be not'ed values.
- if (isa<ConstantInt>(V))
- return true;
-
- // Compares can be inverted if they have a single use.
- if (CmpInst *CI = dyn_cast<CmpInst>(V))
- return CI->hasOneUse();
-
- return false;
-}
-
-static inline Value *dyn_castNotVal(Value *V) {
- // If this is not(not(x)) don't return that this is a not: we want the two
- // not's to be folded first.
- if (BinaryOperator::isNot(V)) {
- Value *Operand = BinaryOperator::getNotArgument(V);
- if (!isFreeToInvert(Operand))
- return Operand;
- }
-
- // Constants can be considered to be not'ed values...
- if (ConstantInt *C = dyn_cast<ConstantInt>(V))
- return ConstantInt::get(C->getType(), ~C->getValue());
- return 0;
-}
-
-
-
-// dyn_castFoldableMul - If this value is a multiply that can be folded into
-// other computations (because it has a constant operand), return the
-// non-constant operand of the multiply, and set CST to point to the multiplier.
-// Otherwise, return null.
-//
-static inline Value *dyn_castFoldableMul(Value *V, ConstantInt *&CST) {
- if (V->hasOneUse() && V->getType()->isInteger())
- if (Instruction *I = dyn_cast<Instruction>(V)) {
- if (I->getOpcode() == Instruction::Mul)
- if ((CST = dyn_cast<ConstantInt>(I->getOperand(1))))
- return I->getOperand(0);
- if (I->getOpcode() == Instruction::Shl)
- if ((CST = dyn_cast<ConstantInt>(I->getOperand(1)))) {
- // The multiplier is really 1 << CST.
- uint32_t BitWidth = cast<IntegerType>(V->getType())->getBitWidth();
- uint32_t CSTVal = CST->getLimitedValue(BitWidth);
- CST = ConstantInt::get(V->getType()->getContext(),
- APInt(BitWidth, 1).shl(CSTVal));
- return I->getOperand(0);
- }
- }
- return 0;
-}
-
-/// AddOne - Add one to a ConstantInt
-static Constant *AddOne(Constant *C) {
- return ConstantExpr::getAdd(C, ConstantInt::get(C->getType(), 1));
-}
-/// SubOne - Subtract one from a ConstantInt
-static Constant *SubOne(ConstantInt *C) {
- return ConstantExpr::getSub(C, ConstantInt::get(C->getType(), 1));
-}
-/// MultiplyOverflows - True if the multiply can not be expressed in an int
-/// this size.
-static bool MultiplyOverflows(ConstantInt *C1, ConstantInt *C2, bool sign) {
- uint32_t W = C1->getBitWidth();
- APInt LHSExt = C1->getValue(), RHSExt = C2->getValue();
- if (sign) {
- LHSExt.sext(W * 2);
- RHSExt.sext(W * 2);
- } else {
- LHSExt.zext(W * 2);
- RHSExt.zext(W * 2);
- }
-
- APInt MulExt = LHSExt * RHSExt;
-
- if (!sign)
- return MulExt.ugt(APInt::getLowBitsSet(W * 2, W));
-
- APInt Min = APInt::getSignedMinValue(W).sext(W * 2);
- APInt Max = APInt::getSignedMaxValue(W).sext(W * 2);
- return MulExt.slt(Min) || MulExt.sgt(Max);
-}
-
-
-
-/// AssociativeOpt - Perform an optimization on an associative operator. This
-/// function is designed to check a chain of associative operators for a
-/// potential to apply a certain optimization. Since the optimization may be
-/// applicable if the expression was reassociated, this checks the chain, then
-/// reassociates the expression as necessary to expose the optimization
-/// opportunity. This makes use of a special Functor, which must define
-/// 'shouldApply' and 'apply' methods.
-///
-template<typename Functor>
-static Instruction *AssociativeOpt(BinaryOperator &Root, const Functor &F) {
- unsigned Opcode = Root.getOpcode();
- Value *LHS = Root.getOperand(0);
-
- // Quick check, see if the immediate LHS matches...
- if (F.shouldApply(LHS))
- return F.apply(Root);
-
- // Otherwise, if the LHS is not of the same opcode as the root, return.
- Instruction *LHSI = dyn_cast<Instruction>(LHS);
- while (LHSI && LHSI->getOpcode() == Opcode && LHSI->hasOneUse()) {
- // Should we apply this transform to the RHS?
- bool ShouldApply = F.shouldApply(LHSI->getOperand(1));
-
- // If not to the RHS, check to see if we should apply to the LHS...
- if (!ShouldApply && F.shouldApply(LHSI->getOperand(0))) {
- cast<BinaryOperator>(LHSI)->swapOperands(); // Make the LHS the RHS
- ShouldApply = true;
- }
-
- // If the functor wants to apply the optimization to the RHS of LHSI,
- // reassociate the expression from ((? op A) op B) to (? op (A op B))
- if (ShouldApply) {
- // Now all of the instructions are in the current basic block, go ahead
- // and perform the reassociation.
- Instruction *TmpLHSI = cast<Instruction>(Root.getOperand(0));
-
- // First move the selected RHS to the LHS of the root...
- Root.setOperand(0, LHSI->getOperand(1));
-
- // Make what used to be the LHS of the root be the user of the root...
- Value *ExtraOperand = TmpLHSI->getOperand(1);
- if (&Root == TmpLHSI) {
- Root.replaceAllUsesWith(Constant::getNullValue(TmpLHSI->getType()));
- return 0;
- }
- Root.replaceAllUsesWith(TmpLHSI); // Users now use TmpLHSI
- TmpLHSI->setOperand(1, &Root); // TmpLHSI now uses the root
- BasicBlock::iterator ARI = &Root; ++ARI;
- TmpLHSI->moveBefore(ARI); // Move TmpLHSI to after Root
- ARI = Root;
-
- // Now propagate the ExtraOperand down the chain of instructions until we
- // get to LHSI.
- while (TmpLHSI != LHSI) {
- Instruction *NextLHSI = cast<Instruction>(TmpLHSI->getOperand(0));
- // Move the instruction to immediately before the chain we are
- // constructing to avoid breaking dominance properties.
- NextLHSI->moveBefore(ARI);
- ARI = NextLHSI;
-
- Value *NextOp = NextLHSI->getOperand(1);
- NextLHSI->setOperand(1, ExtraOperand);
- TmpLHSI = NextLHSI;
- ExtraOperand = NextOp;
- }
-
- // Now that the instructions are reassociated, have the functor perform
- // the transformation...
- return F.apply(Root);
- }
-
- LHSI = dyn_cast<Instruction>(LHSI->getOperand(0));
- }
- return 0;
-}
-
-namespace {
-
-// AddRHS - Implements: X + X --> X << 1
-struct AddRHS {
- Value *RHS;
- explicit AddRHS(Value *rhs) : RHS(rhs) {}
- bool shouldApply(Value *LHS) const { return LHS == RHS; }
- Instruction *apply(BinaryOperator &Add) const {
- return BinaryOperator::CreateShl(Add.getOperand(0),
- ConstantInt::get(Add.getType(), 1));
- }
-};
-
-// AddMaskingAnd - Implements (A & C1)+(B & C2) --> (A & C1)|(B & C2)
-// iff C1&C2 == 0
-struct AddMaskingAnd {
- Constant *C2;
- explicit AddMaskingAnd(Constant *c) : C2(c) {}
- bool shouldApply(Value *LHS) const {
- ConstantInt *C1;
- return match(LHS, m_And(m_Value(), m_ConstantInt(C1))) &&
- ConstantExpr::getAnd(C1, C2)->isNullValue();
- }
- Instruction *apply(BinaryOperator &Add) const {
- return BinaryOperator::CreateOr(Add.getOperand(0), Add.getOperand(1));
- }
-};
-
-}
-
static Value *FoldOperationIntoSelectOperand(Instruction &I, Value *SO,
InstCombiner *IC) {
if (CastInst *CI = dyn_cast<CastInst>(&I))
if (isa<Constant>(TV) || isa<Constant>(FV)) {
// Bool selects with constant operands can be folded to logical ops.
- if (SI->getType() == Type::getInt1Ty(SI->getContext())) return 0;
+ if (SI->getType()->isIntegerTy(1)) return 0;
Value *SelectTrueVal = FoldOperationIntoSelectOperand(Op, TV, this);
Value *SelectFalseVal = FoldOperationIntoSelectOperand(Op, FV, this);
return ReplaceInstUsesWith(I, NewPN);
}
-
-/// WillNotOverflowSignedAdd - Return true if we can prove that:
-/// (sext (add LHS, RHS)) === (add (sext LHS), (sext RHS))
-/// This basically requires proving that the add in the original type would not
-/// overflow to change the sign bit or have a carry out.
-bool InstCombiner::WillNotOverflowSignedAdd(Value *LHS, Value *RHS) {
- // There are different heuristics we can use for this. Here are some simple
- // ones.
-
- // Add has the property that adding any two 2's complement numbers can only
- // have one carry bit which can change a sign. As such, if LHS and RHS each
- // have at least two sign bits, we know that the addition of the two values
- // will sign extend fine.
- if (ComputeNumSignBits(LHS) > 1 && ComputeNumSignBits(RHS) > 1)
- return true;
-
+/// FindElementAtOffset - Given a type and a constant offset, determine whether
+/// or not there is a sequence of GEP indices into the type that will land us at
+/// the specified offset. If so, fill them into NewIndices and return the
+/// resultant element type, otherwise return null.
+const Type *InstCombiner::FindElementAtOffset(const Type *Ty, int64_t Offset,
+ SmallVectorImpl<Value*> &NewIndices) {
+ if (!TD) return 0;
+ if (!Ty->isSized()) return 0;
- // If one of the operands only has one non-zero bit, and if the other operand
- // has a known-zero bit in a more significant place than it (not including the
- // sign bit) the ripple may go up to and fill the zero, but won't change the
- // sign. For example, (X & ~4) + 1.
+ // Start with the index over the outer type. Note that the type size
+ // might be zero (even if the offset isn't zero) if the indexed type
+ // is something like [0 x {int, int}]
+ const Type *IntPtrTy = TD->getIntPtrType(Ty->getContext());
+ int64_t FirstIdx = 0;
+ if (int64_t TySize = TD->getTypeAllocSize(Ty)) {
+ FirstIdx = Offset/TySize;
+ Offset -= FirstIdx*TySize;
+
+ // Handle hosts where % returns negative instead of values [0..TySize).
+ if (Offset < 0) {
+ --FirstIdx;
+ Offset += TySize;
+ assert(Offset >= 0);
+ }
+ assert((uint64_t)Offset < (uint64_t)TySize && "Out of range offset");
+ }
- // TODO: Implement.
+ NewIndices.push_back(ConstantInt::get(IntPtrTy, FirstIdx));
+
+ // Index into the types. If we fail, set OrigBase to null.
+ while (Offset) {
+ // Indexing into tail padding between struct/array elements.
+ if (uint64_t(Offset*8) >= TD->getTypeSizeInBits(Ty))
+ return 0;
+
+ if (const StructType *STy = dyn_cast<StructType>(Ty)) {
+ const StructLayout *SL = TD->getStructLayout(STy);
+ assert(Offset < (int64_t)SL->getSizeInBytes() &&
+ "Offset must stay within the indexed type");
+
+ unsigned Elt = SL->getElementContainingOffset(Offset);
+ NewIndices.push_back(ConstantInt::get(Type::getInt32Ty(Ty->getContext()),
+ Elt));
+
+ Offset -= SL->getElementOffset(Elt);
+ Ty = STy->getElementType(Elt);
+ } else if (const ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
+ uint64_t EltSize = TD->getTypeAllocSize(AT->getElementType());
+ assert(EltSize && "Cannot index into a zero-sized array");
+ NewIndices.push_back(ConstantInt::get(IntPtrTy,Offset/EltSize));
+ Offset %= EltSize;
+ Ty = AT->getElementType();
+ } else {
+ // Otherwise, we can't index into the middle of this atomic type, bail.
+ return 0;
+ }
+ }
- return false;
+ return Ty;
}
-Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
- bool Changed = SimplifyCommutative(I);
- Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
- if (Value *V = SimplifyAddInst(LHS, RHS, I.hasNoSignedWrap(),
- I.hasNoUnsignedWrap(), TD))
- return ReplaceInstUsesWith(I, V);
+Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
+ SmallVector<Value*, 8> Ops(GEP.op_begin(), GEP.op_end());
+
+ if (Value *V = SimplifyGEPInst(&Ops[0], Ops.size(), TD))
+ return ReplaceInstUsesWith(GEP, V);
-
- if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(RHSC)) {
- // X + (signbit) --> X ^ signbit
- const APInt& Val = CI->getValue();
- uint32_t BitWidth = Val.getBitWidth();
- if (Val == APInt::getSignBit(BitWidth))
- return BinaryOperator::CreateXor(LHS, RHS);
-
- // See if SimplifyDemandedBits can simplify this. This handles stuff like
- // (X & 254)+1 -> (X&254)|1
- if (SimplifyDemandedInstructionBits(I))
- return &I;
+ Value *PtrOp = GEP.getOperand(0);
- // zext(bool) + C -> bool ? C + 1 : C
- if (ZExtInst *ZI = dyn_cast<ZExtInst>(LHS))
- if (ZI->getSrcTy() == Type::getInt1Ty(I.getContext()))
- return SelectInst::Create(ZI->getOperand(0), AddOne(CI), CI);
- }
+ if (isa<UndefValue>(GEP.getOperand(0)))
+ return ReplaceInstUsesWith(GEP, UndefValue::get(GEP.getType()));
- if (isa<PHINode>(LHS))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
+ // Eliminate unneeded casts for indices.
+ if (TD) {
+ bool MadeChange = false;
+ unsigned PtrSize = TD->getPointerSizeInBits();
- ConstantInt *XorRHS = 0;
- Value *XorLHS = 0;
- if (isa<ConstantInt>(RHSC) &&
- match(LHS, m_Xor(m_Value(XorLHS), m_ConstantInt(XorRHS)))) {
- uint32_t TySizeBits = I.getType()->getScalarSizeInBits();
- const APInt& RHSVal = cast<ConstantInt>(RHSC)->getValue();
+ gep_type_iterator GTI = gep_type_begin(GEP);
+ for (User::op_iterator I = GEP.op_begin() + 1, E = GEP.op_end();
+ I != E; ++I, ++GTI) {
+ if (!isa<SequentialType>(*GTI)) continue;
- uint32_t Size = TySizeBits / 2;
- APInt C0080Val(APInt(TySizeBits, 1ULL).shl(Size - 1));
- APInt CFF80Val(-C0080Val);
- do {
- if (TySizeBits > Size) {
- // If we have ADD(XOR(AND(X, 0xFF), 0x80), 0xF..F80), it's a sext.
- // If we have ADD(XOR(AND(X, 0xFF), 0xF..F80), 0x80), it's a sext.
- if ((RHSVal == CFF80Val && XorRHS->getValue() == C0080Val) ||
- (RHSVal == C0080Val && XorRHS->getValue() == CFF80Val)) {
- // This is a sign extend if the top bits are known zero.
- if (!MaskedValueIsZero(XorLHS,
- APInt::getHighBitsSet(TySizeBits, TySizeBits - Size)))
- Size = 0; // Not a sign ext, but can't be any others either.
- break;
- }
- }
- Size >>= 1;
- C0080Val = APIntOps::lshr(C0080Val, Size);
- CFF80Val = APIntOps::ashr(CFF80Val, Size);
- } while (Size >= 1);
+ // If we are using a wider index than needed for this platform, shrink it
+ // to what we need. If narrower, sign-extend it to what we need. This
+ // explicit cast can make subsequent optimizations more obvious.
+ unsigned OpBits = cast<IntegerType>((*I)->getType())->getBitWidth();
+ if (OpBits == PtrSize)
+ continue;
- // FIXME: This shouldn't be necessary. When the backends can handle types
- // with funny bit widths then this switch statement should be removed. It
- // is just here to get the size of the "middle" type back up to something
- // that the back ends can handle.
- const Type *MiddleType = 0;
- switch (Size) {
- default: break;
- case 32:
- case 16:
- case 8: MiddleType = IntegerType::get(I.getContext(), Size); break;
- }
- if (MiddleType) {
- Value *NewTrunc = Builder->CreateTrunc(XorLHS, MiddleType, "sext");
- return new SExtInst(NewTrunc, I.getType(), I.getName());
- }
+ *I = Builder->CreateIntCast(*I, TD->getIntPtrType(GEP.getContext()),true);
+ MadeChange = true;
}
+ if (MadeChange) return &GEP;
}
- if (I.getType() == Type::getInt1Ty(I.getContext()))
- return BinaryOperator::CreateXor(LHS, RHS);
+ // Combine Indices - If the source pointer to this getelementptr instruction
+ // is a getelementptr instruction, combine the indices of the two
+ // getelementptr instructions into a single instruction.
+ //
+ if (GEPOperator *Src = dyn_cast<GEPOperator>(PtrOp)) {
+ // Note that if our source is a gep chain itself that we wait for that
+ // chain to be resolved before we perform this transformation. This
+ // avoids us creating a TON of code in some cases.
+ //
+ if (GetElementPtrInst *SrcGEP =
+ dyn_cast<GetElementPtrInst>(Src->getOperand(0)))
+ if (SrcGEP->getNumOperands() == 2)
+ return 0; // Wait until our source is folded to completion.
- // X + X --> X << 1
- if (I.getType()->isInteger()) {
- if (Instruction *Result = AssociativeOpt(I, AddRHS(RHS)))
- return Result;
+ SmallVector<Value*, 8> Indices;
- if (Instruction *RHSI = dyn_cast<Instruction>(RHS)) {
- if (RHSI->getOpcode() == Instruction::Sub)
- if (LHS == RHSI->getOperand(1)) // A + (B - A) --> B
- return ReplaceInstUsesWith(I, RHSI->getOperand(0));
- }
- if (Instruction *LHSI = dyn_cast<Instruction>(LHS)) {
- if (LHSI->getOpcode() == Instruction::Sub)
- if (RHS == LHSI->getOperand(1)) // (B - A) + A --> B
- return ReplaceInstUsesWith(I, LHSI->getOperand(0));
- }
- }
+ // Find out whether the last index in the source GEP is a sequential idx.
+ bool EndsWithSequential = false;
+ for (gep_type_iterator I = gep_type_begin(*Src), E = gep_type_end(*Src);
+ I != E; ++I)
+ EndsWithSequential = !isa<StructType>(*I);
- // -A + B --> B - A
- // -A + -B --> -(A + B)
- if (Value *LHSV = dyn_castNegVal(LHS)) {
- if (LHS->getType()->isIntOrIntVector()) {
- if (Value *RHSV = dyn_castNegVal(RHS)) {
- Value *NewAdd = Builder->CreateAdd(LHSV, RHSV, "sum");
- return BinaryOperator::CreateNeg(NewAdd);
+ // Can we combine the two pointer arithmetics offsets?
+ if (EndsWithSequential) {
+ // Replace: gep (gep %P, long B), long A, ...
+ // With: T = long A+B; gep %P, T, ...
+ //
+ Value *Sum;
+ Value *SO1 = Src->getOperand(Src->getNumOperands()-1);
+ Value *GO1 = GEP.getOperand(1);
+ if (SO1 == Constant::getNullValue(SO1->getType())) {
+ Sum = GO1;
+ } else if (GO1 == Constant::getNullValue(GO1->getType())) {
+ Sum = SO1;
+ } else {
+ // If they aren't the same type, then the input hasn't been processed
+ // by the loop above yet (which canonicalizes sequential index types to
+ // intptr_t). Just avoid transforming this until the input has been
+ // normalized.
+ if (SO1->getType() != GO1->getType())
+ return 0;
+ Sum = Builder->CreateAdd(SO1, GO1, PtrOp->getName()+".sum");
}
- }
-
- return BinaryOperator::CreateSub(RHS, LHSV);
- }
- // A + -B --> A - B
- if (!isa<Constant>(RHS))
- if (Value *V = dyn_castNegVal(RHS))
- return BinaryOperator::CreateSub(LHS, V);
-
-
- ConstantInt *C2;
- if (Value *X = dyn_castFoldableMul(LHS, C2)) {
- if (X == RHS) // X*C + X --> X * (C+1)
- return BinaryOperator::CreateMul(RHS, AddOne(C2));
+ // Update the GEP in place if possible.
+ if (Src->getNumOperands() == 2) {
+ GEP.setOperand(0, Src->getOperand(0));
+ GEP.setOperand(1, Sum);
+ return &GEP;
+ }
+ Indices.append(Src->op_begin()+1, Src->op_end()-1);
+ Indices.push_back(Sum);
+ Indices.append(GEP.op_begin()+2, GEP.op_end());
+ } else if (isa<Constant>(*GEP.idx_begin()) &&
+ cast<Constant>(*GEP.idx_begin())->isNullValue() &&
+ Src->getNumOperands() != 1) {
+ // Otherwise we can do the fold if the first index of the GEP is a zero
+ Indices.append(Src->op_begin()+1, Src->op_end());
+ Indices.append(GEP.idx_begin()+1, GEP.idx_end());
+ }
- // X*C1 + X*C2 --> X * (C1+C2)
- ConstantInt *C1;
- if (X == dyn_castFoldableMul(RHS, C1))
- return BinaryOperator::CreateMul(X, ConstantExpr::getAdd(C1, C2));
+ if (!Indices.empty())
+ return (GEP.isInBounds() && Src->isInBounds()) ?
+ GetElementPtrInst::CreateInBounds(Src->getOperand(0), Indices.begin(),
+ Indices.end(), GEP.getName()) :
+ GetElementPtrInst::Create(Src->getOperand(0), Indices.begin(),
+ Indices.end(), GEP.getName());
}
-
- // X + X*C --> X * (C+1)
- if (dyn_castFoldableMul(RHS, C2) == LHS)
- return BinaryOperator::CreateMul(LHS, AddOne(C2));
-
- // X + ~X --> -1 since ~X = -X-1
- if (dyn_castNotVal(LHS) == RHS ||
- dyn_castNotVal(RHS) == LHS)
- return ReplaceInstUsesWith(I, Constant::getAllOnesValue(I.getType()));
-
-
- // (A & C1)+(B & C2) --> (A & C1)|(B & C2) iff C1&C2 == 0
- if (match(RHS, m_And(m_Value(), m_ConstantInt(C2))))
- if (Instruction *R = AssociativeOpt(I, AddMaskingAnd(C2)))
- return R;
- // A+B --> A|B iff A and B have no bits set in common.
- if (const IntegerType *IT = dyn_cast<IntegerType>(I.getType())) {
- APInt Mask = APInt::getAllOnesValue(IT->getBitWidth());
- APInt LHSKnownOne(IT->getBitWidth(), 0);
- APInt LHSKnownZero(IT->getBitWidth(), 0);
- ComputeMaskedBits(LHS, Mask, LHSKnownZero, LHSKnownOne);
- if (LHSKnownZero != 0) {
- APInt RHSKnownOne(IT->getBitWidth(), 0);
- APInt RHSKnownZero(IT->getBitWidth(), 0);
- ComputeMaskedBits(RHS, Mask, RHSKnownZero, RHSKnownOne);
-
- // No bits in common -> bitwise or.
- if ((LHSKnownZero|RHSKnownZero).isAllOnesValue())
- return BinaryOperator::CreateOr(LHS, RHS);
- }
- }
-
- // W*X + Y*Z --> W * (X+Z) iff W == Y
- if (I.getType()->isIntOrIntVector()) {
- Value *W, *X, *Y, *Z;
- if (match(LHS, m_Mul(m_Value(W), m_Value(X))) &&
- match(RHS, m_Mul(m_Value(Y), m_Value(Z)))) {
- if (W != Y) {
- if (W == Z) {
- std::swap(Y, Z);
- } else if (Y == X) {
- std::swap(W, X);
- } else if (X == Z) {
- std::swap(Y, Z);
- std::swap(W, X);
- }
- }
+ // Handle gep(bitcast x) and gep(gep x, 0, 0, 0).
+ Value *StrippedPtr = PtrOp->stripPointerCasts();
+ if (StrippedPtr != PtrOp) {
+ const PointerType *StrippedPtrTy =cast<PointerType>(StrippedPtr->getType());
- if (W == Y) {
- Value *NewAdd = Builder->CreateAdd(X, Z, LHS->getName());
- return BinaryOperator::CreateMul(W, NewAdd);
- }
- }
- }
-
- if (ConstantInt *CRHS = dyn_cast<ConstantInt>(RHS)) {
- Value *X = 0;
- if (match(LHS, m_Not(m_Value(X)))) // ~X + C --> (C-1) - X
- return BinaryOperator::CreateSub(SubOne(CRHS), X);
-
- // (X & FF00) + xx00 -> (X+xx00) & FF00
- if (LHS->hasOneUse() &&
- match(LHS, m_And(m_Value(X), m_ConstantInt(C2)))) {
- Constant *Anded = ConstantExpr::getAnd(CRHS, C2);
- if (Anded == CRHS) {
- // See if all bits from the first bit set in the Add RHS up are included
- // in the mask. First, get the rightmost bit.
- const APInt& AddRHSV = CRHS->getValue();
-
- // Form a mask of all bits from the lowest bit added through the top.
- APInt AddRHSHighBits(~((AddRHSV & -AddRHSV)-1));
-
- // See if the and mask includes all of these bits.
- APInt AddRHSHighBitsAnd(AddRHSHighBits & C2->getValue());
-
- if (AddRHSHighBits == AddRHSHighBitsAnd) {
- // Okay, the xform is safe. Insert the new add pronto.
- Value *NewAdd = Builder->CreateAdd(X, CRHS, LHS->getName());
- return BinaryOperator::CreateAnd(NewAdd, C2);
- }
- }
- }
-
- // Try to fold constant add into select arguments.
- if (SelectInst *SI = dyn_cast<SelectInst>(LHS))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
- }
-
- // add (select X 0 (sub n A)) A --> select X A n
- {
- SelectInst *SI = dyn_cast<SelectInst>(LHS);
- Value *A = RHS;
- if (!SI) {
- SI = dyn_cast<SelectInst>(RHS);
- A = LHS;
- }
- if (SI && SI->hasOneUse()) {
- Value *TV = SI->getTrueValue();
- Value *FV = SI->getFalseValue();
- Value *N;
-
- // Can we fold the add into the argument of the select?
- // We check both true and false select arguments for a matching subtract.
- if (match(FV, m_Zero()) &&
- match(TV, m_Sub(m_Value(N), m_Specific(A))))
- // Fold the add into the true select value.
- return SelectInst::Create(SI->getCondition(), N, A);
- if (match(TV, m_Zero()) &&
- match(FV, m_Sub(m_Value(N), m_Specific(A))))
- // Fold the add into the false select value.
- return SelectInst::Create(SI->getCondition(), A, N);
- }
- }
-
- // Check for (add (sext x), y), see if we can merge this into an
- // integer add followed by a sext.
- if (SExtInst *LHSConv = dyn_cast<SExtInst>(LHS)) {
- // (add (sext x), cst) --> (sext (add x, cst'))
- if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
- Constant *CI =
- ConstantExpr::getTrunc(RHSC, LHSConv->getOperand(0)->getType());
- if (LHSConv->hasOneUse() &&
- ConstantExpr::getSExt(CI, I.getType()) == RHSC &&
- WillNotOverflowSignedAdd(LHSConv->getOperand(0), CI)) {
- // Insert the new, smaller add.
- Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
- CI, "addconv");
- return new SExtInst(NewAdd, I.getType());
- }
- }
-
- // (add (sext x), (sext y)) --> (sext (add int x, y))
- if (SExtInst *RHSConv = dyn_cast<SExtInst>(RHS)) {
- // Only do this if x/y have the same type, if at last one of them has a
- // single use (so we don't increase the number of sexts), and if the
- // integer add will not overflow.
- if (LHSConv->getOperand(0)->getType()==RHSConv->getOperand(0)->getType()&&
- (LHSConv->hasOneUse() || RHSConv->hasOneUse()) &&
- WillNotOverflowSignedAdd(LHSConv->getOperand(0),
- RHSConv->getOperand(0))) {
- // Insert the new integer add.
- Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
- RHSConv->getOperand(0), "addconv");
- return new SExtInst(NewAdd, I.getType());
- }
- }
- }
-
- return Changed ? &I : 0;
-}
-
-Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
- bool Changed = SimplifyCommutative(I);
- Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
-
- if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
- // X + 0 --> X
- if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
- if (CFP->isExactlyValue(ConstantFP::getNegativeZero
- (I.getType())->getValueAPF()))
- return ReplaceInstUsesWith(I, LHS);
- }
-
- if (isa<PHINode>(LHS))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
- }
-
- // -A + B --> B - A
- // -A + -B --> -(A + B)
- if (Value *LHSV = dyn_castFNegVal(LHS))
- return BinaryOperator::CreateFSub(RHS, LHSV);
-
- // A + -B --> A - B
- if (!isa<Constant>(RHS))
- if (Value *V = dyn_castFNegVal(RHS))
- return BinaryOperator::CreateFSub(LHS, V);
-
- // Check for X+0.0. Simplify it to X if we know X is not -0.0.
- if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHS))
- if (CFP->getValueAPF().isPosZero() && CannotBeNegativeZero(LHS))
- return ReplaceInstUsesWith(I, LHS);
-
- // Check for (add double (sitofp x), y), see if we can merge this into an
- // integer add followed by a promotion.
- if (SIToFPInst *LHSConv = dyn_cast<SIToFPInst>(LHS)) {
- // (add double (sitofp x), fpcst) --> (sitofp (add int x, intcst))
- // ... if the constant fits in the integer value. This is useful for things
- // like (double)(x & 1234) + 4.0 -> (double)((X & 1234)+4) which no longer
- // requires a constant pool load, and generally allows the add to be better
- // instcombined.
- if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHS)) {
- Constant *CI =
- ConstantExpr::getFPToSI(CFP, LHSConv->getOperand(0)->getType());
- if (LHSConv->hasOneUse() &&
- ConstantExpr::getSIToFP(CI, I.getType()) == CFP &&
- WillNotOverflowSignedAdd(LHSConv->getOperand(0), CI)) {
- // Insert the new integer add.
- Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
- CI, "addconv");
- return new SIToFPInst(NewAdd, I.getType());
- }
- }
-
- // (add double (sitofp x), (sitofp y)) --> (sitofp (add int x, y))
- if (SIToFPInst *RHSConv = dyn_cast<SIToFPInst>(RHS)) {
- // Only do this if x/y have the same type, if at last one of them has a
- // single use (so we don't increase the number of int->fp conversions),
- // and if the integer add will not overflow.
- if (LHSConv->getOperand(0)->getType()==RHSConv->getOperand(0)->getType()&&
- (LHSConv->hasOneUse() || RHSConv->hasOneUse()) &&
- WillNotOverflowSignedAdd(LHSConv->getOperand(0),
- RHSConv->getOperand(0))) {
- // Insert the new integer add.
- Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
- RHSConv->getOperand(0),"addconv");
- return new SIToFPInst(NewAdd, I.getType());
- }
- }
- }
-
- return Changed ? &I : 0;
-}
-
-
-/// EmitGEPOffset - Given a getelementptr instruction/constantexpr, emit the
-/// code necessary to compute the offset from the base pointer (without adding
-/// in the base pointer). Return the result as a signed integer of intptr size.
-Value *InstCombiner::EmitGEPOffset(User *GEP) {
- TargetData &TD = *getTargetData();
- gep_type_iterator GTI = gep_type_begin(GEP);
- const Type *IntPtrTy = TD.getIntPtrType(GEP->getContext());
- Value *Result = Constant::getNullValue(IntPtrTy);
-
- // Build a mask for high order bits.
- unsigned IntPtrWidth = TD.getPointerSizeInBits();
- uint64_t PtrSizeMask = ~0ULL >> (64-IntPtrWidth);
-
- for (User::op_iterator i = GEP->op_begin() + 1, e = GEP->op_end(); i != e;
- ++i, ++GTI) {
- Value *Op = *i;
- uint64_t Size = TD.getTypeAllocSize(GTI.getIndexedType()) & PtrSizeMask;
- if (ConstantInt *OpC = dyn_cast<ConstantInt>(Op)) {
- if (OpC->isZero()) continue;
-
- // Handle a struct index, which adds its field offset to the pointer.
- if (const StructType *STy = dyn_cast<StructType>(*GTI)) {
- Size = TD.getStructLayout(STy)->getElementOffset(OpC->getZExtValue());
-
- Result = Builder->CreateAdd(Result,
- ConstantInt::get(IntPtrTy, Size),
- GEP->getName()+".offs");
- continue;
- }
-
- Constant *Scale = ConstantInt::get(IntPtrTy, Size);
- Constant *OC =
- ConstantExpr::getIntegerCast(OpC, IntPtrTy, true /*SExt*/);
- Scale = ConstantExpr::getMul(OC, Scale);
- // Emit an add instruction.
- Result = Builder->CreateAdd(Result, Scale, GEP->getName()+".offs");
- continue;
- }
- // Convert to correct type.
- if (Op->getType() != IntPtrTy)
- Op = Builder->CreateIntCast(Op, IntPtrTy, true, Op->getName()+".c");
- if (Size != 1) {
- Constant *Scale = ConstantInt::get(IntPtrTy, Size);
- // We'll let instcombine(mul) convert this to a shl if possible.
- Op = Builder->CreateMul(Op, Scale, GEP->getName()+".idx");
- }
-
- // Emit an add instruction.
- Result = Builder->CreateAdd(Op, Result, GEP->getName()+".offs");
- }
- return Result;
-}
-
-
-
-
-/// Optimize pointer differences into the same array into a size. Consider:
-/// &A[10] - &A[0]: we should compile this to "10". LHS/RHS are the pointer
-/// operands to the ptrtoint instructions for the LHS/RHS of the subtract.
-///
-Value *InstCombiner::OptimizePointerDifference(Value *LHS, Value *RHS,
- const Type *Ty) {
- assert(TD && "Must have target data info for this");
-
- // If LHS is a gep based on RHS or RHS is a gep based on LHS, we can optimize
- // this.
- bool Swapped;
- GetElementPtrInst *GEP = 0;
- ConstantExpr *CstGEP = 0;
-
- // TODO: Could also optimize &A[i] - &A[j] -> "i-j", and "&A.foo[i] - &A.foo".
- // For now we require one side to be the base pointer "A" or a constant
- // expression derived from it.
- if (GetElementPtrInst *LHSGEP = dyn_cast<GetElementPtrInst>(LHS)) {
- // (gep X, ...) - X
- if (LHSGEP->getOperand(0) == RHS) {
- GEP = LHSGEP;
- Swapped = false;
- } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(RHS)) {
- // (gep X, ...) - (ce_gep X, ...)
- if (CE->getOpcode() == Instruction::GetElementPtr &&
- LHSGEP->getOperand(0) == CE->getOperand(0)) {
- CstGEP = CE;
- GEP = LHSGEP;
- Swapped = false;
- }
- }
- }
-
- if (GetElementPtrInst *RHSGEP = dyn_cast<GetElementPtrInst>(RHS)) {
- // X - (gep X, ...)
- if (RHSGEP->getOperand(0) == LHS) {
- GEP = RHSGEP;
- Swapped = true;
- } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(LHS)) {
- // (ce_gep X, ...) - (gep X, ...)
- if (CE->getOpcode() == Instruction::GetElementPtr &&
- RHSGEP->getOperand(0) == CE->getOperand(0)) {
- CstGEP = CE;
- GEP = RHSGEP;
- Swapped = true;
- }
- }
- }
-
- if (GEP == 0)
- return 0;
-
- // Emit the offset of the GEP and an intptr_t.
- Value *Result = EmitGEPOffset(GEP);
-
- // If we had a constant expression GEP on the other side offsetting the
- // pointer, subtract it from the offset we have.
- if (CstGEP) {
- Value *CstOffset = EmitGEPOffset(CstGEP);
- Result = Builder->CreateSub(Result, CstOffset);
- }
-
-
- // If we have p - gep(p, ...) then we have to negate the result.
- if (Swapped)
- Result = Builder->CreateNeg(Result, "diff.neg");
-
- return Builder->CreateIntCast(Result, Ty, true);
-}
-
-
-Instruction *InstCombiner::visitSub(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- if (Op0 == Op1) // sub X, X -> 0
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
- // If this is a 'B = x-(-A)', change to B = x+A. This preserves NSW/NUW.
- if (Value *V = dyn_castNegVal(Op1)) {
- BinaryOperator *Res = BinaryOperator::CreateAdd(Op0, V);
- Res->setHasNoSignedWrap(I.hasNoSignedWrap());
- Res->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
- return Res;
- }
-
- if (isa<UndefValue>(Op0))
- return ReplaceInstUsesWith(I, Op0); // undef - X -> undef
- if (isa<UndefValue>(Op1))
- return ReplaceInstUsesWith(I, Op1); // X - undef -> undef
- if (I.getType() == Type::getInt1Ty(I.getContext()))
- return BinaryOperator::CreateXor(Op0, Op1);
-
- if (ConstantInt *C = dyn_cast<ConstantInt>(Op0)) {
- // Replace (-1 - A) with (~A).
- if (C->isAllOnesValue())
- return BinaryOperator::CreateNot(Op1);
-
- // C - ~X == X + (1+C)
- Value *X = 0;
- if (match(Op1, m_Not(m_Value(X))))
- return BinaryOperator::CreateAdd(X, AddOne(C));
-
- // -(X >>u 31) -> (X >>s 31)
- // -(X >>s 31) -> (X >>u 31)
- if (C->isZero()) {
- if (BinaryOperator *SI = dyn_cast<BinaryOperator>(Op1)) {
- if (SI->getOpcode() == Instruction::LShr) {
- if (ConstantInt *CU = dyn_cast<ConstantInt>(SI->getOperand(1))) {
- // Check to see if we are shifting out everything but the sign bit.
- if (CU->getLimitedValue(SI->getType()->getPrimitiveSizeInBits()) ==
- SI->getType()->getPrimitiveSizeInBits()-1) {
- // Ok, the transformation is safe. Insert AShr.
- return BinaryOperator::Create(Instruction::AShr,
- SI->getOperand(0), CU, SI->getName());
- }
- }
- } else if (SI->getOpcode() == Instruction::AShr) {
- if (ConstantInt *CU = dyn_cast<ConstantInt>(SI->getOperand(1))) {
- // Check to see if we are shifting out everything but the sign bit.
- if (CU->getLimitedValue(SI->getType()->getPrimitiveSizeInBits()) ==
- SI->getType()->getPrimitiveSizeInBits()-1) {
- // Ok, the transformation is safe. Insert LShr.
- return BinaryOperator::CreateLShr(
- SI->getOperand(0), CU, SI->getName());
- }
- }
- }
- }
- }
-
- // Try to fold constant sub into select arguments.
- if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
-
- // C - zext(bool) -> bool ? C - 1 : C
- if (ZExtInst *ZI = dyn_cast<ZExtInst>(Op1))
- if (ZI->getSrcTy() == Type::getInt1Ty(I.getContext()))
- return SelectInst::Create(ZI->getOperand(0), SubOne(C), C);
- }
-
- if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1)) {
- if (Op1I->getOpcode() == Instruction::Add) {
- if (Op1I->getOperand(0) == Op0) // X-(X+Y) == -Y
- return BinaryOperator::CreateNeg(Op1I->getOperand(1),
- I.getName());
- else if (Op1I->getOperand(1) == Op0) // X-(Y+X) == -Y
- return BinaryOperator::CreateNeg(Op1I->getOperand(0),
- I.getName());
- else if (ConstantInt *CI1 = dyn_cast<ConstantInt>(I.getOperand(0))) {
- if (ConstantInt *CI2 = dyn_cast<ConstantInt>(Op1I->getOperand(1)))
- // C1-(X+C2) --> (C1-C2)-X
- return BinaryOperator::CreateSub(
- ConstantExpr::getSub(CI1, CI2), Op1I->getOperand(0));
- }
- }
-
- if (Op1I->hasOneUse()) {
- // Replace (x - (y - z)) with (x + (z - y)) if the (y - z) subexpression
- // is not used by anyone else...
- //
- if (Op1I->getOpcode() == Instruction::Sub) {
- // Swap the two operands of the subexpr...
- Value *IIOp0 = Op1I->getOperand(0), *IIOp1 = Op1I->getOperand(1);
- Op1I->setOperand(0, IIOp1);
- Op1I->setOperand(1, IIOp0);
-
- // Create the new top level add instruction...
- return BinaryOperator::CreateAdd(Op0, Op1);
- }
-
- // Replace (A - (A & B)) with (A & ~B) if this is the only use of (A&B)...
- //
- if (Op1I->getOpcode() == Instruction::And &&
- (Op1I->getOperand(0) == Op0 || Op1I->getOperand(1) == Op0)) {
- Value *OtherOp = Op1I->getOperand(Op1I->getOperand(0) == Op0);
-
- Value *NewNot = Builder->CreateNot(OtherOp, "B.not");
- return BinaryOperator::CreateAnd(Op0, NewNot);
- }
-
- // 0 - (X sdiv C) -> (X sdiv -C)
- if (Op1I->getOpcode() == Instruction::SDiv)
- if (ConstantInt *CSI = dyn_cast<ConstantInt>(Op0))
- if (CSI->isZero())
- if (Constant *DivRHS = dyn_cast<Constant>(Op1I->getOperand(1)))
- return BinaryOperator::CreateSDiv(Op1I->getOperand(0),
- ConstantExpr::getNeg(DivRHS));
-
- // X - X*C --> X * (1-C)
- ConstantInt *C2 = 0;
- if (dyn_castFoldableMul(Op1I, C2) == Op0) {
- Constant *CP1 =
- ConstantExpr::getSub(ConstantInt::get(I.getType(), 1),
- C2);
- return BinaryOperator::CreateMul(Op0, CP1);
- }
- }
- }
-
- if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
- if (Op0I->getOpcode() == Instruction::Add) {
- if (Op0I->getOperand(0) == Op1) // (Y+X)-Y == X
- return ReplaceInstUsesWith(I, Op0I->getOperand(1));
- else if (Op0I->getOperand(1) == Op1) // (X+Y)-Y == X
- return ReplaceInstUsesWith(I, Op0I->getOperand(0));
- } else if (Op0I->getOpcode() == Instruction::Sub) {
- if (Op0I->getOperand(0) == Op1) // (X-Y)-X == -Y
- return BinaryOperator::CreateNeg(Op0I->getOperand(1),
- I.getName());
- }
- }
-
- ConstantInt *C1;
- if (Value *X = dyn_castFoldableMul(Op0, C1)) {
- if (X == Op1) // X*C - X --> X * (C-1)
- return BinaryOperator::CreateMul(Op1, SubOne(C1));
-
- ConstantInt *C2; // X*C1 - X*C2 -> X * (C1-C2)
- if (X == dyn_castFoldableMul(Op1, C2))
- return BinaryOperator::CreateMul(X, ConstantExpr::getSub(C1, C2));
- }
-
- // Optimize pointer differences into the same array into a size. Consider:
- // &A[10] - &A[0]: we should compile this to "10".
- if (TD) {
- Value *LHSOp, *RHSOp;
- if (match(Op0, m_PtrToInt(m_Value(LHSOp))) &&
- match(Op1, m_PtrToInt(m_Value(RHSOp))))
- if (Value *Res = OptimizePointerDifference(LHSOp, RHSOp, I.getType()))
- return ReplaceInstUsesWith(I, Res);
-
- // trunc(p)-trunc(q) -> trunc(p-q)
- if (match(Op0, m_Trunc(m_PtrToInt(m_Value(LHSOp)))) &&
- match(Op1, m_Trunc(m_PtrToInt(m_Value(RHSOp)))))
- if (Value *Res = OptimizePointerDifference(LHSOp, RHSOp, I.getType()))
- return ReplaceInstUsesWith(I, Res);
- }
-
- return 0;
-}
-
-Instruction *InstCombiner::visitFSub(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- // If this is a 'B = x-(-A)', change to B = x+A...
- if (Value *V = dyn_castFNegVal(Op1))
- return BinaryOperator::CreateFAdd(Op0, V);
-
- if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1)) {
- if (Op1I->getOpcode() == Instruction::FAdd) {
- if (Op1I->getOperand(0) == Op0) // X-(X+Y) == -Y
- return BinaryOperator::CreateFNeg(Op1I->getOperand(1),
- I.getName());
- else if (Op1I->getOperand(1) == Op0) // X-(Y+X) == -Y
- return BinaryOperator::CreateFNeg(Op1I->getOperand(0),
- I.getName());
- }
- }
-
- return 0;
-}
-
-Instruction *InstCombiner::visitMul(BinaryOperator &I) {
- bool Changed = SimplifyCommutative(I);
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- if (isa<UndefValue>(Op1)) // undef * X -> 0
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
- // Simplify mul instructions with a constant RHS.
- if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1C)) {
-
- // ((X << C1)*C2) == (X * (C2 << C1))
- if (BinaryOperator *SI = dyn_cast<BinaryOperator>(Op0))
- if (SI->getOpcode() == Instruction::Shl)
- if (Constant *ShOp = dyn_cast<Constant>(SI->getOperand(1)))
- return BinaryOperator::CreateMul(SI->getOperand(0),
- ConstantExpr::getShl(CI, ShOp));
-
- if (CI->isZero())
- return ReplaceInstUsesWith(I, Op1C); // X * 0 == 0
- if (CI->equalsInt(1)) // X * 1 == X
- return ReplaceInstUsesWith(I, Op0);
- if (CI->isAllOnesValue()) // X * -1 == 0 - X
- return BinaryOperator::CreateNeg(Op0, I.getName());
-
- const APInt& Val = cast<ConstantInt>(CI)->getValue();
- if (Val.isPowerOf2()) { // Replace X*(2^C) with X << C
- return BinaryOperator::CreateShl(Op0,
- ConstantInt::get(Op0->getType(), Val.logBase2()));
- }
- } else if (isa<VectorType>(Op1C->getType())) {
- if (Op1C->isNullValue())
- return ReplaceInstUsesWith(I, Op1C);
-
- if (ConstantVector *Op1V = dyn_cast<ConstantVector>(Op1C)) {
- if (Op1V->isAllOnesValue()) // X * -1 == 0 - X
- return BinaryOperator::CreateNeg(Op0, I.getName());
-
- // As above, vector X*splat(1.0) -> X in all defined cases.
- if (Constant *Splat = Op1V->getSplatValue()) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(Splat))
- if (CI->equalsInt(1))
- return ReplaceInstUsesWith(I, Op0);
- }
- }
- }
-
- if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0))
- if (Op0I->getOpcode() == Instruction::Add && Op0I->hasOneUse() &&
- isa<ConstantInt>(Op0I->getOperand(1)) && isa<ConstantInt>(Op1C)) {
- // Canonicalize (X+C1)*C2 -> X*C2+C1*C2.
- Value *Add = Builder->CreateMul(Op0I->getOperand(0), Op1C, "tmp");
- Value *C1C2 = Builder->CreateMul(Op1C, Op0I->getOperand(1));
- return BinaryOperator::CreateAdd(Add, C1C2);
-
- }
-
- // Try to fold constant mul into select arguments.
- if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
-
- if (isa<PHINode>(Op0))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
- }
-
- if (Value *Op0v = dyn_castNegVal(Op0)) // -X * -Y = X*Y
- if (Value *Op1v = dyn_castNegVal(Op1))
- return BinaryOperator::CreateMul(Op0v, Op1v);
-
- // (X / Y) * Y = X - (X % Y)
- // (X / Y) * -Y = (X % Y) - X
- {
- Value *Op1C = Op1;
- BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0);
- if (!BO ||
- (BO->getOpcode() != Instruction::UDiv &&
- BO->getOpcode() != Instruction::SDiv)) {
- Op1C = Op0;
- BO = dyn_cast<BinaryOperator>(Op1);
- }
- Value *Neg = dyn_castNegVal(Op1C);
- if (BO && BO->hasOneUse() &&
- (BO->getOperand(1) == Op1C || BO->getOperand(1) == Neg) &&
- (BO->getOpcode() == Instruction::UDiv ||
- BO->getOpcode() == Instruction::SDiv)) {
- Value *Op0BO = BO->getOperand(0), *Op1BO = BO->getOperand(1);
-
- // If the division is exact, X % Y is zero.
- if (SDivOperator *SDiv = dyn_cast<SDivOperator>(BO))
- if (SDiv->isExact()) {
- if (Op1BO == Op1C)
- return ReplaceInstUsesWith(I, Op0BO);
- return BinaryOperator::CreateNeg(Op0BO);
- }
-
- Value *Rem;
- if (BO->getOpcode() == Instruction::UDiv)
- Rem = Builder->CreateURem(Op0BO, Op1BO);
- else
- Rem = Builder->CreateSRem(Op0BO, Op1BO);
- Rem->takeName(BO);
-
- if (Op1BO == Op1C)
- return BinaryOperator::CreateSub(Op0BO, Rem);
- return BinaryOperator::CreateSub(Rem, Op0BO);
- }
- }
-
- /// i1 mul -> i1 and.
- if (I.getType() == Type::getInt1Ty(I.getContext()))
- return BinaryOperator::CreateAnd(Op0, Op1);
-
- // X*(1 << Y) --> X << Y
- // (1 << Y)*X --> X << Y
- {
- Value *Y;
- if (match(Op0, m_Shl(m_One(), m_Value(Y))))
- return BinaryOperator::CreateShl(Op1, Y);
- if (match(Op1, m_Shl(m_One(), m_Value(Y))))
- return BinaryOperator::CreateShl(Op0, Y);
- }
-
- // If one of the operands of the multiply is a cast from a boolean value, then
- // we know the bool is either zero or one, so this is a 'masking' multiply.
- // X * Y (where Y is 0 or 1) -> X & (0-Y)
- if (!isa<VectorType>(I.getType())) {
- // -2 is "-1 << 1" so it is all bits set except the low one.
- APInt Negative2(I.getType()->getPrimitiveSizeInBits(), (uint64_t)-2, true);
-
- Value *BoolCast = 0, *OtherOp = 0;
- if (MaskedValueIsZero(Op0, Negative2))
- BoolCast = Op0, OtherOp = Op1;
- else if (MaskedValueIsZero(Op1, Negative2))
- BoolCast = Op1, OtherOp = Op0;
-
- if (BoolCast) {
- Value *V = Builder->CreateSub(Constant::getNullValue(I.getType()),
- BoolCast, "tmp");
- return BinaryOperator::CreateAnd(V, OtherOp);
- }
- }
-
- return Changed ? &I : 0;
-}
-
-Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
- bool Changed = SimplifyCommutative(I);
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- // Simplify mul instructions with a constant RHS...
- if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
- if (ConstantFP *Op1F = dyn_cast<ConstantFP>(Op1C)) {
- // "In IEEE floating point, x*1 is not equivalent to x for nans. However,
- // ANSI says we can drop signals, so we can do this anyway." (from GCC)
- if (Op1F->isExactlyValue(1.0))
- return ReplaceInstUsesWith(I, Op0); // Eliminate 'mul double %X, 1.0'
- } else if (isa<VectorType>(Op1C->getType())) {
- if (ConstantVector *Op1V = dyn_cast<ConstantVector>(Op1C)) {
- // As above, vector X*splat(1.0) -> X in all defined cases.
- if (Constant *Splat = Op1V->getSplatValue()) {
- if (ConstantFP *F = dyn_cast<ConstantFP>(Splat))
- if (F->isExactlyValue(1.0))
- return ReplaceInstUsesWith(I, Op0);
- }
- }
- }
-
- // Try to fold constant mul into select arguments.
- if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
-
- if (isa<PHINode>(Op0))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
- }
-
- if (Value *Op0v = dyn_castFNegVal(Op0)) // -X * -Y = X*Y
- if (Value *Op1v = dyn_castFNegVal(Op1))
- return BinaryOperator::CreateFMul(Op0v, Op1v);
-
- return Changed ? &I : 0;
-}
-
-/// SimplifyDivRemOfSelect - Try to fold a divide or remainder of a select
-/// instruction.
-bool InstCombiner::SimplifyDivRemOfSelect(BinaryOperator &I) {
- SelectInst *SI = cast<SelectInst>(I.getOperand(1));
-
- // div/rem X, (Cond ? 0 : Y) -> div/rem X, Y
- int NonNullOperand = -1;
- if (Constant *ST = dyn_cast<Constant>(SI->getOperand(1)))
- if (ST->isNullValue())
- NonNullOperand = 2;
- // div/rem X, (Cond ? Y : 0) -> div/rem X, Y
- if (Constant *ST = dyn_cast<Constant>(SI->getOperand(2)))
- if (ST->isNullValue())
- NonNullOperand = 1;
-
- if (NonNullOperand == -1)
- return false;
-
- Value *SelectCond = SI->getOperand(0);
-
- // Change the div/rem to use 'Y' instead of the select.
- I.setOperand(1, SI->getOperand(NonNullOperand));
-
- // Okay, we know we replace the operand of the div/rem with 'Y' with no
- // problem. However, the select, or the condition of the select may have
- // multiple uses. Based on our knowledge that the operand must be non-zero,
- // propagate the known value for the select into other uses of it, and
- // propagate a known value of the condition into its other users.
-
- // If the select and condition only have a single use, don't bother with this,
- // early exit.
- if (SI->use_empty() && SelectCond->hasOneUse())
- return true;
-
- // Scan the current block backward, looking for other uses of SI.
- BasicBlock::iterator BBI = &I, BBFront = I.getParent()->begin();
-
- while (BBI != BBFront) {
- --BBI;
- // If we found a call to a function, we can't assume it will return, so
- // information from below it cannot be propagated above it.
- if (isa<CallInst>(BBI) && !isa<IntrinsicInst>(BBI))
- break;
-
- // Replace uses of the select or its condition with the known values.
- for (Instruction::op_iterator I = BBI->op_begin(), E = BBI->op_end();
- I != E; ++I) {
- if (*I == SI) {
- *I = SI->getOperand(NonNullOperand);
- Worklist.Add(BBI);
- } else if (*I == SelectCond) {
- *I = NonNullOperand == 1 ? ConstantInt::getTrue(BBI->getContext()) :
- ConstantInt::getFalse(BBI->getContext());
- Worklist.Add(BBI);
- }
- }
-
- // If we past the instruction, quit looking for it.
- if (&*BBI == SI)
- SI = 0;
- if (&*BBI == SelectCond)
- SelectCond = 0;
-
- // If we ran out of things to eliminate, break out of the loop.
- if (SelectCond == 0 && SI == 0)
- break;
-
- }
- return true;
-}
-
-
-/// This function implements the transforms on div instructions that work
-/// regardless of the kind of div instruction it is (udiv, sdiv, or fdiv). It is
-/// used by the visitors to those instructions.
-/// @brief Transforms common to all three div instructions
-Instruction *InstCombiner::commonDivTransforms(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- // undef / X -> 0 for integer.
- // undef / X -> undef for FP (the undef could be a snan).
- if (isa<UndefValue>(Op0)) {
- if (Op0->getType()->isFPOrFPVector())
- return ReplaceInstUsesWith(I, Op0);
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- }
-
- // X / undef -> undef
- if (isa<UndefValue>(Op1))
- return ReplaceInstUsesWith(I, Op1);
-
- return 0;
-}
-
-/// This function implements the transforms common to both integer division
-/// instructions (udiv and sdiv). It is called by the visitors to those integer
-/// division instructions.
-/// @brief Common integer divide transforms
-Instruction *InstCombiner::commonIDivTransforms(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- // (sdiv X, X) --> 1 (udiv X, X) --> 1
- if (Op0 == Op1) {
- if (const VectorType *Ty = dyn_cast<VectorType>(I.getType())) {
- Constant *CI = ConstantInt::get(Ty->getElementType(), 1);
- std::vector<Constant*> Elts(Ty->getNumElements(), CI);
- return ReplaceInstUsesWith(I, ConstantVector::get(Elts));
- }
-
- Constant *CI = ConstantInt::get(I.getType(), 1);
- return ReplaceInstUsesWith(I, CI);
- }
-
- if (Instruction *Common = commonDivTransforms(I))
- return Common;
-
- // Handle cases involving: [su]div X, (select Cond, Y, Z)
- // This does not apply for fdiv.
- if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
- return &I;
-
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- // div X, 1 == X
- if (RHS->equalsInt(1))
- return ReplaceInstUsesWith(I, Op0);
-
- // (X / C1) / C2 -> X / (C1*C2)
- if (Instruction *LHS = dyn_cast<Instruction>(Op0))
- if (Instruction::BinaryOps(LHS->getOpcode()) == I.getOpcode())
- if (ConstantInt *LHSRHS = dyn_cast<ConstantInt>(LHS->getOperand(1))) {
- if (MultiplyOverflows(RHS, LHSRHS,
- I.getOpcode()==Instruction::SDiv))
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- else
- return BinaryOperator::Create(I.getOpcode(), LHS->getOperand(0),
- ConstantExpr::getMul(RHS, LHSRHS));
- }
-
- if (!RHS->isZero()) { // avoid X udiv 0
- if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
- if (isa<PHINode>(Op0))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
- }
- }
-
- // 0 / X == 0, we don't need to preserve faults!
- if (ConstantInt *LHS = dyn_cast<ConstantInt>(Op0))
- if (LHS->equalsInt(0))
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
- // It can't be division by zero, hence it must be division by one.
- if (I.getType() == Type::getInt1Ty(I.getContext()))
- return ReplaceInstUsesWith(I, Op0);
-
- if (ConstantVector *Op1V = dyn_cast<ConstantVector>(Op1)) {
- if (ConstantInt *X = cast_or_null<ConstantInt>(Op1V->getSplatValue()))
- // div X, 1 == X
- if (X->isOne())
- return ReplaceInstUsesWith(I, Op0);
- }
-
- return 0;
-}
-
-Instruction *InstCombiner::visitUDiv(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- // Handle the integer div common cases
- if (Instruction *Common = commonIDivTransforms(I))
- return Common;
-
- if (ConstantInt *C = dyn_cast<ConstantInt>(Op1)) {
- // X udiv C^2 -> X >> C
- // Check to see if this is an unsigned division with an exact power of 2,
- // if so, convert to a right shift.
- if (C->getValue().isPowerOf2()) // 0 not included in isPowerOf2
- return BinaryOperator::CreateLShr(Op0,
- ConstantInt::get(Op0->getType(), C->getValue().logBase2()));
-
- // X udiv C, where C >= signbit
- if (C->getValue().isNegative()) {
- Value *IC = Builder->CreateICmpULT( Op0, C);
- return SelectInst::Create(IC, Constant::getNullValue(I.getType()),
- ConstantInt::get(I.getType(), 1));
- }
- }
-
- // X udiv (C1 << N), where C1 is "1<<C2" --> X >> (N+C2)
- if (BinaryOperator *RHSI = dyn_cast<BinaryOperator>(I.getOperand(1))) {
- if (RHSI->getOpcode() == Instruction::Shl &&
- isa<ConstantInt>(RHSI->getOperand(0))) {
- const APInt& C1 = cast<ConstantInt>(RHSI->getOperand(0))->getValue();
- if (C1.isPowerOf2()) {
- Value *N = RHSI->getOperand(1);
- const Type *NTy = N->getType();
- if (uint32_t C2 = C1.logBase2())
- N = Builder->CreateAdd(N, ConstantInt::get(NTy, C2), "tmp");
- return BinaryOperator::CreateLShr(Op0, N);
- }
- }
- }
-
- // udiv X, (Select Cond, C1, C2) --> Select Cond, (shr X, C1), (shr X, C2)
- // where C1&C2 are powers of two.
- if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
- if (ConstantInt *STO = dyn_cast<ConstantInt>(SI->getOperand(1)))
- if (ConstantInt *SFO = dyn_cast<ConstantInt>(SI->getOperand(2))) {
- const APInt &TVA = STO->getValue(), &FVA = SFO->getValue();
- if (TVA.isPowerOf2() && FVA.isPowerOf2()) {
- // Compute the shift amounts
- uint32_t TSA = TVA.logBase2(), FSA = FVA.logBase2();
- // Construct the "on true" case of the select
- Constant *TC = ConstantInt::get(Op0->getType(), TSA);
- Value *TSI = Builder->CreateLShr(Op0, TC, SI->getName()+".t");
-
- // Construct the "on false" case of the select
- Constant *FC = ConstantInt::get(Op0->getType(), FSA);
- Value *FSI = Builder->CreateLShr(Op0, FC, SI->getName()+".f");
-
- // construct the select instruction and return it.
- return SelectInst::Create(SI->getOperand(0), TSI, FSI, SI->getName());
- }
- }
- return 0;
-}
-
-Instruction *InstCombiner::visitSDiv(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- // Handle the integer div common cases
- if (Instruction *Common = commonIDivTransforms(I))
- return Common;
-
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- // sdiv X, -1 == -X
- if (RHS->isAllOnesValue())
- return BinaryOperator::CreateNeg(Op0);
-
- // sdiv X, C --> ashr X, log2(C)
- if (cast<SDivOperator>(&I)->isExact() &&
- RHS->getValue().isNonNegative() &&
- RHS->getValue().isPowerOf2()) {
- Value *ShAmt = llvm::ConstantInt::get(RHS->getType(),
- RHS->getValue().exactLogBase2());
- return BinaryOperator::CreateAShr(Op0, ShAmt, I.getName());
- }
-
- // -X/C --> X/-C provided the negation doesn't overflow.
- if (SubOperator *Sub = dyn_cast<SubOperator>(Op0))
- if (isa<Constant>(Sub->getOperand(0)) &&
- cast<Constant>(Sub->getOperand(0))->isNullValue() &&
- Sub->hasNoSignedWrap())
- return BinaryOperator::CreateSDiv(Sub->getOperand(1),
- ConstantExpr::getNeg(RHS));
- }
-
- // If the sign bits of both operands are zero (i.e. we can prove they are
- // unsigned inputs), turn this into a udiv.
- if (I.getType()->isInteger()) {
- APInt Mask(APInt::getSignBit(I.getType()->getPrimitiveSizeInBits()));
- if (MaskedValueIsZero(Op0, Mask)) {
- if (MaskedValueIsZero(Op1, Mask)) {
- // X sdiv Y -> X udiv Y, iff X and Y don't have sign bit set
- return BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
- }
- ConstantInt *ShiftedInt;
- if (match(Op1, m_Shl(m_ConstantInt(ShiftedInt), m_Value())) &&
- ShiftedInt->getValue().isPowerOf2()) {
- // X sdiv (1 << Y) -> X udiv (1 << Y) ( -> X u>> Y)
- // Safe because the only negative value (1 << Y) can take on is
- // INT_MIN, and X sdiv INT_MIN == X udiv INT_MIN == 0 if X doesn't have
- // the sign bit set.
- return BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
- }
- }
- }
-
- return 0;
-}
-
-Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
- return commonDivTransforms(I);
-}
-
-/// This function implements the transforms on rem instructions that work
-/// regardless of the kind of rem instruction it is (urem, srem, or frem). It
-/// is used by the visitors to those instructions.
-/// @brief Transforms common to all three rem instructions
-Instruction *InstCombiner::commonRemTransforms(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- if (isa<UndefValue>(Op0)) { // undef % X -> 0
- if (I.getType()->isFPOrFPVector())
- return ReplaceInstUsesWith(I, Op0); // X % undef -> undef (could be SNaN)
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- }
- if (isa<UndefValue>(Op1))
- return ReplaceInstUsesWith(I, Op1); // X % undef -> undef
-
- // Handle cases involving: rem X, (select Cond, Y, Z)
- if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
- return &I;
-
- return 0;
-}
-
-/// This function implements the transforms common to both integer remainder
-/// instructions (urem and srem). It is called by the visitors to those integer
-/// remainder instructions.
-/// @brief Common integer remainder transforms
-Instruction *InstCombiner::commonIRemTransforms(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- if (Instruction *common = commonRemTransforms(I))
- return common;
-
- // 0 % X == 0 for integer, we don't need to preserve faults!
- if (Constant *LHS = dyn_cast<Constant>(Op0))
- if (LHS->isNullValue())
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- // X % 0 == undef, we don't need to preserve faults!
- if (RHS->equalsInt(0))
- return ReplaceInstUsesWith(I, UndefValue::get(I.getType()));
-
- if (RHS->equalsInt(1)) // X % 1 == 0
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
- if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) {
- if (SelectInst *SI = dyn_cast<SelectInst>(Op0I)) {
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
- } else if (isa<PHINode>(Op0I)) {
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
- }
-
- // See if we can fold away this rem instruction.
- if (SimplifyDemandedInstructionBits(I))
- return &I;
- }
- }
-
- return 0;
-}
-
-Instruction *InstCombiner::visitURem(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- if (Instruction *common = commonIRemTransforms(I))
- return common;
-
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- // X urem C^2 -> X and C
- // Check to see if this is an unsigned remainder with an exact power of 2,
- // if so, convert to a bitwise and.
- if (ConstantInt *C = dyn_cast<ConstantInt>(RHS))
- if (C->getValue().isPowerOf2())
- return BinaryOperator::CreateAnd(Op0, SubOne(C));
- }
-
- if (Instruction *RHSI = dyn_cast<Instruction>(I.getOperand(1))) {
- // Turn A % (C << N), where C is 2^k, into A & ((C << N)-1)
- if (RHSI->getOpcode() == Instruction::Shl &&
- isa<ConstantInt>(RHSI->getOperand(0))) {
- if (cast<ConstantInt>(RHSI->getOperand(0))->getValue().isPowerOf2()) {
- Constant *N1 = Constant::getAllOnesValue(I.getType());
- Value *Add = Builder->CreateAdd(RHSI, N1, "tmp");
- return BinaryOperator::CreateAnd(Op0, Add);
- }
- }
- }
-
- // urem X, (select Cond, 2^C1, 2^C2) --> select Cond, (and X, C1), (and X, C2)
- // where C1&C2 are powers of two.
- if (SelectInst *SI = dyn_cast<SelectInst>(Op1)) {
- if (ConstantInt *STO = dyn_cast<ConstantInt>(SI->getOperand(1)))
- if (ConstantInt *SFO = dyn_cast<ConstantInt>(SI->getOperand(2))) {
- // STO == 0 and SFO == 0 handled above.
- if ((STO->getValue().isPowerOf2()) &&
- (SFO->getValue().isPowerOf2())) {
- Value *TrueAnd = Builder->CreateAnd(Op0, SubOne(STO),
- SI->getName()+".t");
- Value *FalseAnd = Builder->CreateAnd(Op0, SubOne(SFO),
- SI->getName()+".f");
- return SelectInst::Create(SI->getOperand(0), TrueAnd, FalseAnd);
- }
- }
- }
-
- return 0;
-}
-
-Instruction *InstCombiner::visitSRem(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- // Handle the integer rem common cases
- if (Instruction *Common = commonIRemTransforms(I))
- return Common;
-
- if (Value *RHSNeg = dyn_castNegVal(Op1))
- if (!isa<Constant>(RHSNeg) ||
- (isa<ConstantInt>(RHSNeg) &&
- cast<ConstantInt>(RHSNeg)->getValue().isStrictlyPositive())) {
- // X % -Y -> X % Y
- Worklist.AddValue(I.getOperand(1));
- I.setOperand(1, RHSNeg);
- return &I;
- }
-
- // If the sign bits of both operands are zero (i.e. we can prove they are
- // unsigned inputs), turn this into a urem.
- if (I.getType()->isInteger()) {
- APInt Mask(APInt::getSignBit(I.getType()->getPrimitiveSizeInBits()));
- if (MaskedValueIsZero(Op1, Mask) && MaskedValueIsZero(Op0, Mask)) {
- // X srem Y -> X urem Y, iff X and Y don't have sign bit set
- return BinaryOperator::CreateURem(Op0, Op1, I.getName());
- }
- }
-
- // If it's a constant vector, flip any negative values positive.
- if (ConstantVector *RHSV = dyn_cast<ConstantVector>(Op1)) {
- unsigned VWidth = RHSV->getNumOperands();
-
- bool hasNegative = false;
- for (unsigned i = 0; !hasNegative && i != VWidth; ++i)
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(RHSV->getOperand(i)))
- if (RHS->getValue().isNegative())
- hasNegative = true;
-
- if (hasNegative) {
- std::vector<Constant *> Elts(VWidth);
- for (unsigned i = 0; i != VWidth; ++i) {
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(RHSV->getOperand(i))) {
- if (RHS->getValue().isNegative())
- Elts[i] = cast<ConstantInt>(ConstantExpr::getNeg(RHS));
- else
- Elts[i] = RHS;
- }
- }
-
- Constant *NewRHSV = ConstantVector::get(Elts);
- if (NewRHSV != RHSV) {
- Worklist.AddValue(I.getOperand(1));
- I.setOperand(1, NewRHSV);
- return &I;
- }
- }
- }
-
- return 0;
-}
-
-Instruction *InstCombiner::visitFRem(BinaryOperator &I) {
- return commonRemTransforms(I);
-}
-
-// isOneBitSet - Return true if there is exactly one bit set in the specified
-// constant.
-static bool isOneBitSet(const ConstantInt *CI) {
- return CI->getValue().isPowerOf2();
-}
-
-/// getICmpCode - Encode a icmp predicate into a three bit mask. These bits
-/// are carefully arranged to allow folding of expressions such as:
-///
-/// (A < B) | (A > B) --> (A != B)
-///
-/// Note that this is only valid if the first and second predicates have the
-/// same sign. Is illegal to do: (A u< B) | (A s> B)
-///
-/// Three bits are used to represent the condition, as follows:
-/// 0 A > B
-/// 1 A == B
-/// 2 A < B
-///
-/// <=> Value Definition
-/// 000 0 Always false
-/// 001 1 A > B
-/// 010 2 A == B
-/// 011 3 A >= B
-/// 100 4 A < B
-/// 101 5 A != B
-/// 110 6 A <= B
-/// 111 7 Always true
-///
-static unsigned getICmpCode(const ICmpInst *ICI) {
- switch (ICI->getPredicate()) {
- // False -> 0
- case ICmpInst::ICMP_UGT: return 1; // 001
- case ICmpInst::ICMP_SGT: return 1; // 001
- case ICmpInst::ICMP_EQ: return 2; // 010
- case ICmpInst::ICMP_UGE: return 3; // 011
- case ICmpInst::ICMP_SGE: return 3; // 011
- case ICmpInst::ICMP_ULT: return 4; // 100
- case ICmpInst::ICMP_SLT: return 4; // 100
- case ICmpInst::ICMP_NE: return 5; // 101
- case ICmpInst::ICMP_ULE: return 6; // 110
- case ICmpInst::ICMP_SLE: return 6; // 110
- // True -> 7
- default:
- llvm_unreachable("Invalid ICmp predicate!");
- return 0;
- }
-}
-
-/// getFCmpCode - Similar to getICmpCode but for FCmpInst. This encodes a fcmp
-/// predicate into a three bit mask. It also returns whether it is an ordered
-/// predicate by reference.
-static unsigned getFCmpCode(FCmpInst::Predicate CC, bool &isOrdered) {
- isOrdered = false;
- switch (CC) {
- case FCmpInst::FCMP_ORD: isOrdered = true; return 0; // 000
- case FCmpInst::FCMP_UNO: return 0; // 000
- case FCmpInst::FCMP_OGT: isOrdered = true; return 1; // 001
- case FCmpInst::FCMP_UGT: return 1; // 001
- case FCmpInst::FCMP_OEQ: isOrdered = true; return 2; // 010
- case FCmpInst::FCMP_UEQ: return 2; // 010
- case FCmpInst::FCMP_OGE: isOrdered = true; return 3; // 011
- case FCmpInst::FCMP_UGE: return 3; // 011
- case FCmpInst::FCMP_OLT: isOrdered = true; return 4; // 100
- case FCmpInst::FCMP_ULT: return 4; // 100
- case FCmpInst::FCMP_ONE: isOrdered = true; return 5; // 101
- case FCmpInst::FCMP_UNE: return 5; // 101
- case FCmpInst::FCMP_OLE: isOrdered = true; return 6; // 110
- case FCmpInst::FCMP_ULE: return 6; // 110
- // True -> 7
- default:
- // Not expecting FCMP_FALSE and FCMP_TRUE;
- llvm_unreachable("Unexpected FCmp predicate!");
- return 0;
- }
-}
-
-/// getICmpValue - This is the complement of getICmpCode, which turns an
-/// opcode and two operands into either a constant true or false, or a brand
-/// new ICmp instruction. The sign is passed in to determine which kind
-/// of predicate to use in the new icmp instruction.
-static Value *getICmpValue(bool sign, unsigned code, Value *LHS, Value *RHS) {
- switch (code) {
- default: llvm_unreachable("Illegal ICmp code!");
- case 0: return ConstantInt::getFalse(LHS->getContext());
- case 1:
- if (sign)
- return new ICmpInst(ICmpInst::ICMP_SGT, LHS, RHS);
- else
- return new ICmpInst(ICmpInst::ICMP_UGT, LHS, RHS);
- case 2: return new ICmpInst(ICmpInst::ICMP_EQ, LHS, RHS);
- case 3:
- if (sign)
- return new ICmpInst(ICmpInst::ICMP_SGE, LHS, RHS);
- else
- return new ICmpInst(ICmpInst::ICMP_UGE, LHS, RHS);
- case 4:
- if (sign)
- return new ICmpInst(ICmpInst::ICMP_SLT, LHS, RHS);
- else
- return new ICmpInst(ICmpInst::ICMP_ULT, LHS, RHS);
- case 5: return new ICmpInst(ICmpInst::ICMP_NE, LHS, RHS);
- case 6:
- if (sign)
- return new ICmpInst(ICmpInst::ICMP_SLE, LHS, RHS);
- else
- return new ICmpInst(ICmpInst::ICMP_ULE, LHS, RHS);
- case 7: return ConstantInt::getTrue(LHS->getContext());
- }
-}
-
-/// getFCmpValue - This is the complement of getFCmpCode, which turns an
-/// opcode and two operands into either a FCmp instruction. isordered is passed
-/// in to determine which kind of predicate to use in the new fcmp instruction.
-static Value *getFCmpValue(bool isordered, unsigned code,
- Value *LHS, Value *RHS) {
- switch (code) {
- default: llvm_unreachable("Illegal FCmp code!");
- case 0:
- if (isordered)
- return new FCmpInst(FCmpInst::FCMP_ORD, LHS, RHS);
- else
- return new FCmpInst(FCmpInst::FCMP_UNO, LHS, RHS);
- case 1:
- if (isordered)
- return new FCmpInst(FCmpInst::FCMP_OGT, LHS, RHS);
- else
- return new FCmpInst(FCmpInst::FCMP_UGT, LHS, RHS);
- case 2:
- if (isordered)
- return new FCmpInst(FCmpInst::FCMP_OEQ, LHS, RHS);
- else
- return new FCmpInst(FCmpInst::FCMP_UEQ, LHS, RHS);
- case 3:
- if (isordered)
- return new FCmpInst(FCmpInst::FCMP_OGE, LHS, RHS);
- else
- return new FCmpInst(FCmpInst::FCMP_UGE, LHS, RHS);
- case 4:
- if (isordered)
- return new FCmpInst(FCmpInst::FCMP_OLT, LHS, RHS);
- else
- return new FCmpInst(FCmpInst::FCMP_ULT, LHS, RHS);
- case 5:
- if (isordered)
- return new FCmpInst(FCmpInst::FCMP_ONE, LHS, RHS);
- else
- return new FCmpInst(FCmpInst::FCMP_UNE, LHS, RHS);
- case 6:
- if (isordered)
- return new FCmpInst(FCmpInst::FCMP_OLE, LHS, RHS);
- else
- return new FCmpInst(FCmpInst::FCMP_ULE, LHS, RHS);
- case 7: return ConstantInt::getTrue(LHS->getContext());
- }
-}
-
-/// PredicatesFoldable - Return true if both predicates match sign or if at
-/// least one of them is an equality comparison (which is signless).
-static bool PredicatesFoldable(ICmpInst::Predicate p1, ICmpInst::Predicate p2) {
- return (CmpInst::isSigned(p1) == CmpInst::isSigned(p2)) ||
- (CmpInst::isSigned(p1) && ICmpInst::isEquality(p2)) ||
- (CmpInst::isSigned(p2) && ICmpInst::isEquality(p1));
-}
-
-namespace {
-// FoldICmpLogical - Implements (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
-struct FoldICmpLogical {
- InstCombiner &IC;
- Value *LHS, *RHS;
- ICmpInst::Predicate pred;
- FoldICmpLogical(InstCombiner &ic, ICmpInst *ICI)
- : IC(ic), LHS(ICI->getOperand(0)), RHS(ICI->getOperand(1)),
- pred(ICI->getPredicate()) {}
- bool shouldApply(Value *V) const {
- if (ICmpInst *ICI = dyn_cast<ICmpInst>(V))
- if (PredicatesFoldable(pred, ICI->getPredicate()))
- return ((ICI->getOperand(0) == LHS && ICI->getOperand(1) == RHS) ||
- (ICI->getOperand(0) == RHS && ICI->getOperand(1) == LHS));
- return false;
- }
- Instruction *apply(Instruction &Log) const {
- ICmpInst *ICI = cast<ICmpInst>(Log.getOperand(0));
- if (ICI->getOperand(0) != LHS) {
- assert(ICI->getOperand(1) == LHS);
- ICI->swapOperands(); // Swap the LHS and RHS of the ICmp
- }
-
- ICmpInst *RHSICI = cast<ICmpInst>(Log.getOperand(1));
- unsigned LHSCode = getICmpCode(ICI);
- unsigned RHSCode = getICmpCode(RHSICI);
- unsigned Code;
- switch (Log.getOpcode()) {
- case Instruction::And: Code = LHSCode & RHSCode; break;
- case Instruction::Or: Code = LHSCode | RHSCode; break;
- case Instruction::Xor: Code = LHSCode ^ RHSCode; break;
- default: llvm_unreachable("Illegal logical opcode!"); return 0;
- }
-
- bool isSigned = RHSICI->isSigned() || ICI->isSigned();
- Value *RV = getICmpValue(isSigned, Code, LHS, RHS);
- if (Instruction *I = dyn_cast<Instruction>(RV))
- return I;
- // Otherwise, it's a constant boolean value...
- return IC.ReplaceInstUsesWith(Log, RV);
- }
-};
-} // end anonymous namespace
-
-// OptAndOp - This handles expressions of the form ((val OP C1) & C2). Where
-// the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'. Op is
-// guaranteed to be a binary operator.
-Instruction *InstCombiner::OptAndOp(Instruction *Op,
- ConstantInt *OpRHS,
- ConstantInt *AndRHS,
- BinaryOperator &TheAnd) {
- Value *X = Op->getOperand(0);
- Constant *Together = 0;
- if (!Op->isShift())
- Together = ConstantExpr::getAnd(AndRHS, OpRHS);
-
- switch (Op->getOpcode()) {
- case Instruction::Xor:
- if (Op->hasOneUse()) {
- // (X ^ C1) & C2 --> (X & C2) ^ (C1&C2)
- Value *And = Builder->CreateAnd(X, AndRHS);
- And->takeName(Op);
- return BinaryOperator::CreateXor(And, Together);
- }
- break;
- case Instruction::Or:
- if (Together == AndRHS) // (X | C) & C --> C
- return ReplaceInstUsesWith(TheAnd, AndRHS);
-
- if (Op->hasOneUse() && Together != OpRHS) {
- // (X | C1) & C2 --> (X | (C1&C2)) & C2
- Value *Or = Builder->CreateOr(X, Together);
- Or->takeName(Op);
- return BinaryOperator::CreateAnd(Or, AndRHS);
- }
- break;
- case Instruction::Add:
- if (Op->hasOneUse()) {
- // Adding a one to a single bit bit-field should be turned into an XOR
- // of the bit. First thing to check is to see if this AND is with a
- // single bit constant.
- const APInt& AndRHSV = cast<ConstantInt>(AndRHS)->getValue();
-
- // If there is only one bit set...
- if (isOneBitSet(cast<ConstantInt>(AndRHS))) {
- // Ok, at this point, we know that we are masking the result of the
- // ADD down to exactly one bit. If the constant we are adding has
- // no bits set below this bit, then we can eliminate the ADD.
- const APInt& AddRHS = cast<ConstantInt>(OpRHS)->getValue();
-
- // Check to see if any bits below the one bit set in AndRHSV are set.
- if ((AddRHS & (AndRHSV-1)) == 0) {
- // If not, the only thing that can effect the output of the AND is
- // the bit specified by AndRHSV. If that bit is set, the effect of
- // the XOR is to toggle the bit. If it is clear, then the ADD has
- // no effect.
- if ((AddRHS & AndRHSV) == 0) { // Bit is not set, noop
- TheAnd.setOperand(0, X);
- return &TheAnd;
- } else {
- // Pull the XOR out of the AND.
- Value *NewAnd = Builder->CreateAnd(X, AndRHS);
- NewAnd->takeName(Op);
- return BinaryOperator::CreateXor(NewAnd, AndRHS);
- }
- }
- }
- }
- break;
-
- case Instruction::Shl: {
- // We know that the AND will not produce any of the bits shifted in, so if
- // the anded constant includes them, clear them now!
- //
- uint32_t BitWidth = AndRHS->getType()->getBitWidth();
- uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
- APInt ShlMask(APInt::getHighBitsSet(BitWidth, BitWidth-OpRHSVal));
- ConstantInt *CI = ConstantInt::get(AndRHS->getContext(),
- AndRHS->getValue() & ShlMask);
-
- if (CI->getValue() == ShlMask) {
- // Masking out bits that the shift already masks
- return ReplaceInstUsesWith(TheAnd, Op); // No need for the and.
- } else if (CI != AndRHS) { // Reducing bits set in and.
- TheAnd.setOperand(1, CI);
- return &TheAnd;
- }
- break;
- }
- case Instruction::LShr: {
- // We know that the AND will not produce any of the bits shifted in, so if
- // the anded constant includes them, clear them now! This only applies to
- // unsigned shifts, because a signed shr may bring in set bits!
- //
- uint32_t BitWidth = AndRHS->getType()->getBitWidth();
- uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
- APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
- ConstantInt *CI = ConstantInt::get(Op->getContext(),
- AndRHS->getValue() & ShrMask);
-
- if (CI->getValue() == ShrMask) {
- // Masking out bits that the shift already masks.
- return ReplaceInstUsesWith(TheAnd, Op);
- } else if (CI != AndRHS) {
- TheAnd.setOperand(1, CI); // Reduce bits set in and cst.
- return &TheAnd;
- }
- break;
- }
- case Instruction::AShr:
- // Signed shr.
- // See if this is shifting in some sign extension, then masking it out
- // with an and.
- if (Op->hasOneUse()) {
- uint32_t BitWidth = AndRHS->getType()->getBitWidth();
- uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
- APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
- Constant *C = ConstantInt::get(Op->getContext(),
- AndRHS->getValue() & ShrMask);
- if (C == AndRHS) { // Masking out bits shifted in.
- // (Val ashr C1) & C2 -> (Val lshr C1) & C2
- // Make the argument unsigned.
- Value *ShVal = Op->getOperand(0);
- ShVal = Builder->CreateLShr(ShVal, OpRHS, Op->getName());
- return BinaryOperator::CreateAnd(ShVal, AndRHS, TheAnd.getName());
- }
- }
- break;
- }
- return 0;
-}
-
-
-/// InsertRangeTest - Emit a computation of: (V >= Lo && V < Hi) if Inside is
-/// true, otherwise (V < Lo || V >= Hi). In pratice, we emit the more efficient
-/// (V-Lo) <u Hi-Lo. This method expects that Lo <= Hi. isSigned indicates
-/// whether to treat the V, Lo and HI as signed or not. IB is the location to
-/// insert new instructions.
-Instruction *InstCombiner::InsertRangeTest(Value *V, Constant *Lo, Constant *Hi,
- bool isSigned, bool Inside,
- Instruction &IB) {
- assert(cast<ConstantInt>(ConstantExpr::getICmp((isSigned ?
- ICmpInst::ICMP_SLE:ICmpInst::ICMP_ULE), Lo, Hi))->getZExtValue() &&
- "Lo is not <= Hi in range emission code!");
-
- if (Inside) {
- if (Lo == Hi) // Trivially false.
- return new ICmpInst(ICmpInst::ICMP_NE, V, V);
-
- // V >= Min && V < Hi --> V < Hi
- if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) {
- ICmpInst::Predicate pred = (isSigned ?
- ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT);
- return new ICmpInst(pred, V, Hi);
- }
-
- // Emit V-Lo <u Hi-Lo
- Constant *NegLo = ConstantExpr::getNeg(Lo);
- Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off");
- Constant *UpperBound = ConstantExpr::getAdd(NegLo, Hi);
- return new ICmpInst(ICmpInst::ICMP_ULT, Add, UpperBound);
- }
-
- if (Lo == Hi) // Trivially true.
- return new ICmpInst(ICmpInst::ICMP_EQ, V, V);
-
- // V < Min || V >= Hi -> V > Hi-1
- Hi = SubOne(cast<ConstantInt>(Hi));
- if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) {
- ICmpInst::Predicate pred = (isSigned ?
- ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT);
- return new ICmpInst(pred, V, Hi);
- }
-
- // Emit V-Lo >u Hi-1-Lo
- // Note that Hi has already had one subtracted from it, above.
- ConstantInt *NegLo = cast<ConstantInt>(ConstantExpr::getNeg(Lo));
- Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off");
- Constant *LowerBound = ConstantExpr::getAdd(NegLo, Hi);
- return new ICmpInst(ICmpInst::ICMP_UGT, Add, LowerBound);
-}
-
-// isRunOfOnes - Returns true iff Val consists of one contiguous run of 1s with
-// any number of 0s on either side. The 1s are allowed to wrap from LSB to
-// MSB, so 0x000FFF0, 0x0000FFFF, and 0xFF0000FF are all runs. 0x0F0F0000 is
-// not, since all 1s are not contiguous.
-static bool isRunOfOnes(ConstantInt *Val, uint32_t &MB, uint32_t &ME) {
- const APInt& V = Val->getValue();
- uint32_t BitWidth = Val->getType()->getBitWidth();
- if (!APIntOps::isShiftedMask(BitWidth, V)) return false;
-
- // look for the first zero bit after the run of ones
- MB = BitWidth - ((V - 1) ^ V).countLeadingZeros();
- // look for the first non-zero bit
- ME = V.getActiveBits();
- return true;
-}
-
-/// FoldLogicalPlusAnd - This is part of an expression (LHS +/- RHS) & Mask,
-/// where isSub determines whether the operator is a sub. If we can fold one of
-/// the following xforms:
-///
-/// ((A & N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == Mask
-/// ((A | N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == 0
-/// ((A ^ N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == 0
-///
-/// return (A +/- B).
-///
-Value *InstCombiner::FoldLogicalPlusAnd(Value *LHS, Value *RHS,
- ConstantInt *Mask, bool isSub,
- Instruction &I) {
- Instruction *LHSI = dyn_cast<Instruction>(LHS);
- if (!LHSI || LHSI->getNumOperands() != 2 ||
- !isa<ConstantInt>(LHSI->getOperand(1))) return 0;
-
- ConstantInt *N = cast<ConstantInt>(LHSI->getOperand(1));
-
- switch (LHSI->getOpcode()) {
- default: return 0;
- case Instruction::And:
- if (ConstantExpr::getAnd(N, Mask) == Mask) {
- // If the AndRHS is a power of two minus one (0+1+), this is simple.
- if ((Mask->getValue().countLeadingZeros() +
- Mask->getValue().countPopulation()) ==
- Mask->getValue().getBitWidth())
- break;
-
- // Otherwise, if Mask is 0+1+0+, and if B is known to have the low 0+
- // part, we don't need any explicit masks to take them out of A. If that
- // is all N is, ignore it.
- uint32_t MB = 0, ME = 0;
- if (isRunOfOnes(Mask, MB, ME)) { // begin/end bit of run, inclusive
- uint32_t BitWidth = cast<IntegerType>(RHS->getType())->getBitWidth();
- APInt Mask(APInt::getLowBitsSet(BitWidth, MB-1));
- if (MaskedValueIsZero(RHS, Mask))
- break;
- }
- }
- return 0;
- case Instruction::Or:
- case Instruction::Xor:
- // If the AndRHS is a power of two minus one (0+1+), and N&Mask == 0
- if ((Mask->getValue().countLeadingZeros() +
- Mask->getValue().countPopulation()) == Mask->getValue().getBitWidth()
- && ConstantExpr::getAnd(N, Mask)->isNullValue())
- break;
- return 0;
- }
-
- if (isSub)
- return Builder->CreateSub(LHSI->getOperand(0), RHS, "fold");
- return Builder->CreateAdd(LHSI->getOperand(0), RHS, "fold");
-}
-
-/// FoldAndOfICmps - Fold (icmp)&(icmp) if possible.
-Instruction *InstCombiner::FoldAndOfICmps(Instruction &I,
- ICmpInst *LHS, ICmpInst *RHS) {
- Value *Val, *Val2;
- ConstantInt *LHSCst, *RHSCst;
- ICmpInst::Predicate LHSCC, RHSCC;
-
- // This only handles icmp of constants: (icmp1 A, C1) & (icmp2 B, C2).
- if (!match(LHS, m_ICmp(LHSCC, m_Value(Val),
- m_ConstantInt(LHSCst))) ||
- !match(RHS, m_ICmp(RHSCC, m_Value(Val2),
- m_ConstantInt(RHSCst))))
- return 0;
-
- if (LHSCst == RHSCst && LHSCC == RHSCC) {
- // (icmp ult A, C) & (icmp ult B, C) --> (icmp ult (A|B), C)
- // where C is a power of 2
- if (LHSCC == ICmpInst::ICMP_ULT &&
- LHSCst->getValue().isPowerOf2()) {
- Value *NewOr = Builder->CreateOr(Val, Val2);
- return new ICmpInst(LHSCC, NewOr, LHSCst);
- }
-
- // (icmp eq A, 0) & (icmp eq B, 0) --> (icmp eq (A|B), 0)
- if (LHSCC == ICmpInst::ICMP_EQ && LHSCst->isZero()) {
- Value *NewOr = Builder->CreateOr(Val, Val2);
- return new ICmpInst(LHSCC, NewOr, LHSCst);
- }
- }
-
- // From here on, we only handle:
- // (icmp1 A, C1) & (icmp2 A, C2) --> something simpler.
- if (Val != Val2) return 0;
-
- // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
- if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE ||
- RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE ||
- LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE ||
- RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE)
- return 0;
-
- // We can't fold (ugt x, C) & (sgt x, C2).
- if (!PredicatesFoldable(LHSCC, RHSCC))
- return 0;
-
- // Ensure that the larger constant is on the RHS.
- bool ShouldSwap;
- if (CmpInst::isSigned(LHSCC) ||
- (ICmpInst::isEquality(LHSCC) &&
- CmpInst::isSigned(RHSCC)))
- ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue());
- else
- ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue());
-
- if (ShouldSwap) {
- std::swap(LHS, RHS);
- std::swap(LHSCst, RHSCst);
- std::swap(LHSCC, RHSCC);
- }
-
- // At this point, we know we have have two icmp instructions
- // comparing a value against two constants and and'ing the result
- // together. Because of the above check, we know that we only have
- // icmp eq, icmp ne, icmp [su]lt, and icmp [SU]gt here. We also know
- // (from the FoldICmpLogical check above), that the two constants
- // are not equal and that the larger constant is on the RHS
- assert(LHSCst != RHSCst && "Compares not folded above?");
-
- switch (LHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ: // (X == 13 & X == 15) -> false
- case ICmpInst::ICMP_UGT: // (X == 13 & X > 15) -> false
- case ICmpInst::ICMP_SGT: // (X == 13 & X > 15) -> false
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
- case ICmpInst::ICMP_NE: // (X == 13 & X != 15) -> X == 13
- case ICmpInst::ICMP_ULT: // (X == 13 & X < 15) -> X == 13
- case ICmpInst::ICMP_SLT: // (X == 13 & X < 15) -> X == 13
- return ReplaceInstUsesWith(I, LHS);
- }
- case ICmpInst::ICMP_NE:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_ULT:
- if (LHSCst == SubOne(RHSCst)) // (X != 13 & X u< 14) -> X < 13
- return new ICmpInst(ICmpInst::ICMP_ULT, Val, LHSCst);
- break; // (X != 13 & X u< 15) -> no change
- case ICmpInst::ICMP_SLT:
- if (LHSCst == SubOne(RHSCst)) // (X != 13 & X s< 14) -> X < 13
- return new ICmpInst(ICmpInst::ICMP_SLT, Val, LHSCst);
- break; // (X != 13 & X s< 15) -> no change
- case ICmpInst::ICMP_EQ: // (X != 13 & X == 15) -> X == 15
- case ICmpInst::ICMP_UGT: // (X != 13 & X u> 15) -> X u> 15
- case ICmpInst::ICMP_SGT: // (X != 13 & X s> 15) -> X s> 15
- return ReplaceInstUsesWith(I, RHS);
- case ICmpInst::ICMP_NE:
- if (LHSCst == SubOne(RHSCst)){// (X != 13 & X != 14) -> X-13 >u 1
- Constant *AddCST = ConstantExpr::getNeg(LHSCst);
- Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off");
- return new ICmpInst(ICmpInst::ICMP_UGT, Add,
- ConstantInt::get(Add->getType(), 1));
- }
- break; // (X != 13 & X != 15) -> no change
- }
- break;
- case ICmpInst::ICMP_ULT:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ: // (X u< 13 & X == 15) -> false
- case ICmpInst::ICMP_UGT: // (X u< 13 & X u> 15) -> false
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
- case ICmpInst::ICMP_SGT: // (X u< 13 & X s> 15) -> no change
- break;
- case ICmpInst::ICMP_NE: // (X u< 13 & X != 15) -> X u< 13
- case ICmpInst::ICMP_ULT: // (X u< 13 & X u< 15) -> X u< 13
- return ReplaceInstUsesWith(I, LHS);
- case ICmpInst::ICMP_SLT: // (X u< 13 & X s< 15) -> no change
- break;
- }
- break;
- case ICmpInst::ICMP_SLT:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ: // (X s< 13 & X == 15) -> false
- case ICmpInst::ICMP_SGT: // (X s< 13 & X s> 15) -> false
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
- case ICmpInst::ICMP_UGT: // (X s< 13 & X u> 15) -> no change
- break;
- case ICmpInst::ICMP_NE: // (X s< 13 & X != 15) -> X < 13
- case ICmpInst::ICMP_SLT: // (X s< 13 & X s< 15) -> X < 13
- return ReplaceInstUsesWith(I, LHS);
- case ICmpInst::ICMP_ULT: // (X s< 13 & X u< 15) -> no change
- break;
- }
- break;
- case ICmpInst::ICMP_UGT:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ: // (X u> 13 & X == 15) -> X == 15
- case ICmpInst::ICMP_UGT: // (X u> 13 & X u> 15) -> X u> 15
- return ReplaceInstUsesWith(I, RHS);
- case ICmpInst::ICMP_SGT: // (X u> 13 & X s> 15) -> no change
- break;
- case ICmpInst::ICMP_NE:
- if (RHSCst == AddOne(LHSCst)) // (X u> 13 & X != 14) -> X u> 14
- return new ICmpInst(LHSCC, Val, RHSCst);
- break; // (X u> 13 & X != 15) -> no change
- case ICmpInst::ICMP_ULT: // (X u> 13 & X u< 15) -> (X-14) <u 1
- return InsertRangeTest(Val, AddOne(LHSCst),
- RHSCst, false, true, I);
- case ICmpInst::ICMP_SLT: // (X u> 13 & X s< 15) -> no change
- break;
- }
- break;
- case ICmpInst::ICMP_SGT:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ: // (X s> 13 & X == 15) -> X == 15
- case ICmpInst::ICMP_SGT: // (X s> 13 & X s> 15) -> X s> 15
- return ReplaceInstUsesWith(I, RHS);
- case ICmpInst::ICMP_UGT: // (X s> 13 & X u> 15) -> no change
- break;
- case ICmpInst::ICMP_NE:
- if (RHSCst == AddOne(LHSCst)) // (X s> 13 & X != 14) -> X s> 14
- return new ICmpInst(LHSCC, Val, RHSCst);
- break; // (X s> 13 & X != 15) -> no change
- case ICmpInst::ICMP_SLT: // (X s> 13 & X s< 15) -> (X-14) s< 1
- return InsertRangeTest(Val, AddOne(LHSCst),
- RHSCst, true, true, I);
- case ICmpInst::ICMP_ULT: // (X s> 13 & X u< 15) -> no change
- break;
- }
- break;
- }
-
- return 0;
-}
-
-Instruction *InstCombiner::FoldAndOfFCmps(Instruction &I, FCmpInst *LHS,
- FCmpInst *RHS) {
-
- if (LHS->getPredicate() == FCmpInst::FCMP_ORD &&
- RHS->getPredicate() == FCmpInst::FCMP_ORD) {
- // (fcmp ord x, c) & (fcmp ord y, c) -> (fcmp ord x, y)
- if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
- if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
- // If either of the constants are nans, then the whole thing returns
- // false.
- if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
- return new FCmpInst(FCmpInst::FCMP_ORD,
- LHS->getOperand(0), RHS->getOperand(0));
- }
-
- // Handle vector zeros. This occurs because the canonical form of
- // "fcmp ord x,x" is "fcmp ord x, 0".
- if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
- isa<ConstantAggregateZero>(RHS->getOperand(1)))
- return new FCmpInst(FCmpInst::FCMP_ORD,
- LHS->getOperand(0), RHS->getOperand(0));
- return 0;
- }
-
- Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
- Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
- FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
-
-
- if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
- // Swap RHS operands to match LHS.
- Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
- std::swap(Op1LHS, Op1RHS);
- }
-
- if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) {
- // Simplify (fcmp cc0 x, y) & (fcmp cc1 x, y).
- if (Op0CC == Op1CC)
- return new FCmpInst((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS);
-
- if (Op0CC == FCmpInst::FCMP_FALSE || Op1CC == FCmpInst::FCMP_FALSE)
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
- if (Op0CC == FCmpInst::FCMP_TRUE)
- return ReplaceInstUsesWith(I, RHS);
- if (Op1CC == FCmpInst::FCMP_TRUE)
- return ReplaceInstUsesWith(I, LHS);
-
- bool Op0Ordered;
- bool Op1Ordered;
- unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
- unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
- if (Op1Pred == 0) {
- std::swap(LHS, RHS);
- std::swap(Op0Pred, Op1Pred);
- std::swap(Op0Ordered, Op1Ordered);
- }
- if (Op0Pred == 0) {
- // uno && ueq -> uno && (uno || eq) -> ueq
- // ord && olt -> ord && (ord && lt) -> olt
- if (Op0Ordered == Op1Ordered)
- return ReplaceInstUsesWith(I, RHS);
-
- // uno && oeq -> uno && (ord && eq) -> false
- // uno && ord -> false
- if (!Op0Ordered)
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
- // ord && ueq -> ord && (uno || eq) -> oeq
- return cast<Instruction>(getFCmpValue(true, Op1Pred, Op0LHS, Op0RHS));
- }
- }
-
- return 0;
-}
-
-
-Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
- bool Changed = SimplifyCommutative(I);
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- if (Value *V = SimplifyAndInst(Op0, Op1, TD))
- return ReplaceInstUsesWith(I, V);
-
- // See if we can simplify any instructions used by the instruction whose sole
- // purpose is to compute bits we don't care about.
- if (SimplifyDemandedInstructionBits(I))
- return &I;
-
- if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(Op1)) {
- const APInt &AndRHSMask = AndRHS->getValue();
- APInt NotAndRHS(~AndRHSMask);
-
- // Optimize a variety of ((val OP C1) & C2) combinations...
- if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
- Value *Op0LHS = Op0I->getOperand(0);
- Value *Op0RHS = Op0I->getOperand(1);
- switch (Op0I->getOpcode()) {
- default: break;
- case Instruction::Xor:
- case Instruction::Or:
- // If the mask is only needed on one incoming arm, push it up.
- if (!Op0I->hasOneUse()) break;
-
- if (MaskedValueIsZero(Op0LHS, NotAndRHS)) {
- // Not masking anything out for the LHS, move to RHS.
- Value *NewRHS = Builder->CreateAnd(Op0RHS, AndRHS,
- Op0RHS->getName()+".masked");
- return BinaryOperator::Create(Op0I->getOpcode(), Op0LHS, NewRHS);
- }
- if (!isa<Constant>(Op0RHS) &&
- MaskedValueIsZero(Op0RHS, NotAndRHS)) {
- // Not masking anything out for the RHS, move to LHS.
- Value *NewLHS = Builder->CreateAnd(Op0LHS, AndRHS,
- Op0LHS->getName()+".masked");
- return BinaryOperator::Create(Op0I->getOpcode(), NewLHS, Op0RHS);
- }
-
- break;
- case Instruction::Add:
- // ((A & N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == AndRHS.
- // ((A | N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0
- // ((A ^ N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0
- if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, false, I))
- return BinaryOperator::CreateAnd(V, AndRHS);
- if (Value *V = FoldLogicalPlusAnd(Op0RHS, Op0LHS, AndRHS, false, I))
- return BinaryOperator::CreateAnd(V, AndRHS); // Add commutes
- break;
-
- case Instruction::Sub:
- // ((A & N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == AndRHS.
- // ((A | N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0
- // ((A ^ N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0
- if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, true, I))
- return BinaryOperator::CreateAnd(V, AndRHS);
-
- // (A - N) & AndRHS -> -N & AndRHS iff A&AndRHS==0 and AndRHS
- // has 1's for all bits that the subtraction with A might affect.
- if (Op0I->hasOneUse()) {
- uint32_t BitWidth = AndRHSMask.getBitWidth();
- uint32_t Zeros = AndRHSMask.countLeadingZeros();
- APInt Mask = APInt::getLowBitsSet(BitWidth, BitWidth - Zeros);
-
- ConstantInt *A = dyn_cast<ConstantInt>(Op0LHS);
- if (!(A && A->isZero()) && // avoid infinite recursion.
- MaskedValueIsZero(Op0LHS, Mask)) {
- Value *NewNeg = Builder->CreateNeg(Op0RHS);
- return BinaryOperator::CreateAnd(NewNeg, AndRHS);
- }
- }
- break;
-
- case Instruction::Shl:
- case Instruction::LShr:
- // (1 << x) & 1 --> zext(x == 0)
- // (1 >> x) & 1 --> zext(x == 0)
- if (AndRHSMask == 1 && Op0LHS == AndRHS) {
- Value *NewICmp =
- Builder->CreateICmpEQ(Op0RHS, Constant::getNullValue(I.getType()));
- return new ZExtInst(NewICmp, I.getType());
- }
- break;
- }
-
- if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1)))
- if (Instruction *Res = OptAndOp(Op0I, Op0CI, AndRHS, I))
- return Res;
- } else if (CastInst *CI = dyn_cast<CastInst>(Op0)) {
- // If this is an integer truncation or change from signed-to-unsigned, and
- // if the source is an and/or with immediate, transform it. This
- // frequently occurs for bitfield accesses.
- if (Instruction *CastOp = dyn_cast<Instruction>(CI->getOperand(0))) {
- if ((isa<TruncInst>(CI) || isa<BitCastInst>(CI)) &&
- CastOp->getNumOperands() == 2)
- if (ConstantInt *AndCI =dyn_cast<ConstantInt>(CastOp->getOperand(1))){
- if (CastOp->getOpcode() == Instruction::And) {
- // Change: and (cast (and X, C1) to T), C2
- // into : and (cast X to T), trunc_or_bitcast(C1)&C2
- // This will fold the two constants together, which may allow
- // other simplifications.
- Value *NewCast = Builder->CreateTruncOrBitCast(
- CastOp->getOperand(0), I.getType(),
- CastOp->getName()+".shrunk");
- // trunc_or_bitcast(C1)&C2
- Constant *C3 = ConstantExpr::getTruncOrBitCast(AndCI,I.getType());
- C3 = ConstantExpr::getAnd(C3, AndRHS);
- return BinaryOperator::CreateAnd(NewCast, C3);
- } else if (CastOp->getOpcode() == Instruction::Or) {
- // Change: and (cast (or X, C1) to T), C2
- // into : trunc(C1)&C2 iff trunc(C1)&C2 == C2
- Constant *C3 = ConstantExpr::getTruncOrBitCast(AndCI,I.getType());
- if (ConstantExpr::getAnd(C3, AndRHS) == AndRHS)
- // trunc(C1)&C2
- return ReplaceInstUsesWith(I, AndRHS);
- }
- }
- }
- }
-
- // Try to fold constant and into select arguments.
- if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
- if (isa<PHINode>(Op0))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
- }
-
-
- // (~A & ~B) == (~(A | B)) - De Morgan's Law
- if (Value *Op0NotVal = dyn_castNotVal(Op0))
- if (Value *Op1NotVal = dyn_castNotVal(Op1))
- if (Op0->hasOneUse() && Op1->hasOneUse()) {
- Value *Or = Builder->CreateOr(Op0NotVal, Op1NotVal,
- I.getName()+".demorgan");
- return BinaryOperator::CreateNot(Or);
- }
-
- {
- Value *A = 0, *B = 0, *C = 0, *D = 0;
- // (A|B) & ~(A&B) -> A^B
- if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
- match(Op1, m_Not(m_And(m_Value(C), m_Value(D)))) &&
- ((A == C && B == D) || (A == D && B == C)))
- return BinaryOperator::CreateXor(A, B);
-
- // ~(A&B) & (A|B) -> A^B
- if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
- match(Op0, m_Not(m_And(m_Value(C), m_Value(D)))) &&
- ((A == C && B == D) || (A == D && B == C)))
- return BinaryOperator::CreateXor(A, B);
-
- if (Op0->hasOneUse() &&
- match(Op0, m_Xor(m_Value(A), m_Value(B)))) {
- if (A == Op1) { // (A^B)&A -> A&(A^B)
- I.swapOperands(); // Simplify below
- std::swap(Op0, Op1);
- } else if (B == Op1) { // (A^B)&B -> B&(B^A)
- cast<BinaryOperator>(Op0)->swapOperands();
- I.swapOperands(); // Simplify below
- std::swap(Op0, Op1);
- }
- }
-
- if (Op1->hasOneUse() &&
- match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
- if (B == Op0) { // B&(A^B) -> B&(B^A)
- cast<BinaryOperator>(Op1)->swapOperands();
- std::swap(A, B);
- }
- if (A == Op0) // A&(A^B) -> A & ~B
- return BinaryOperator::CreateAnd(A, Builder->CreateNot(B, "tmp"));
- }
-
- // (A&((~A)|B)) -> A&B
- if (match(Op0, m_Or(m_Not(m_Specific(Op1)), m_Value(A))) ||
- match(Op0, m_Or(m_Value(A), m_Not(m_Specific(Op1)))))
- return BinaryOperator::CreateAnd(A, Op1);
- if (match(Op1, m_Or(m_Not(m_Specific(Op0)), m_Value(A))) ||
- match(Op1, m_Or(m_Value(A), m_Not(m_Specific(Op0)))))
- return BinaryOperator::CreateAnd(A, Op0);
- }
-
- if (ICmpInst *RHS = dyn_cast<ICmpInst>(Op1)) {
- // (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
- if (Instruction *R = AssociativeOpt(I, FoldICmpLogical(*this, RHS)))
- return R;
-
- if (ICmpInst *LHS = dyn_cast<ICmpInst>(Op0))
- if (Instruction *Res = FoldAndOfICmps(I, LHS, RHS))
- return Res;
- }
-
- // fold (and (cast A), (cast B)) -> (cast (and A, B))
- if (CastInst *Op0C = dyn_cast<CastInst>(Op0))
- if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
- if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind ?
- const Type *SrcTy = Op0C->getOperand(0)->getType();
- if (SrcTy == Op1C->getOperand(0)->getType() &&
- SrcTy->isIntOrIntVector() &&
- // Only do this if the casts both really cause code to be generated.
- ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0),
- I.getType()) &&
- ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0),
- I.getType())) {
- Value *NewOp = Builder->CreateAnd(Op0C->getOperand(0),
- Op1C->getOperand(0), I.getName());
- return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
- }
- }
-
- // (X >> Z) & (Y >> Z) -> (X&Y) >> Z for all shifts.
- if (BinaryOperator *SI1 = dyn_cast<BinaryOperator>(Op1)) {
- if (BinaryOperator *SI0 = dyn_cast<BinaryOperator>(Op0))
- if (SI0->isShift() && SI0->getOpcode() == SI1->getOpcode() &&
- SI0->getOperand(1) == SI1->getOperand(1) &&
- (SI0->hasOneUse() || SI1->hasOneUse())) {
- Value *NewOp =
- Builder->CreateAnd(SI0->getOperand(0), SI1->getOperand(0),
- SI0->getName());
- return BinaryOperator::Create(SI1->getOpcode(), NewOp,
- SI1->getOperand(1));
- }
- }
-
- // If and'ing two fcmp, try combine them into one.
- if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0))) {
- if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
- if (Instruction *Res = FoldAndOfFCmps(I, LHS, RHS))
- return Res;
- }
-
- return Changed ? &I : 0;
-}
-
-/// CollectBSwapParts - Analyze the specified subexpression and see if it is
-/// capable of providing pieces of a bswap. The subexpression provides pieces
-/// of a bswap if it is proven that each of the non-zero bytes in the output of
-/// the expression came from the corresponding "byte swapped" byte in some other
-/// value. For example, if the current subexpression is "(shl i32 %X, 24)" then
-/// we know that the expression deposits the low byte of %X into the high byte
-/// of the bswap result and that all other bytes are zero. This expression is
-/// accepted, the high byte of ByteValues is set to X to indicate a correct
-/// match.
-///
-/// This function returns true if the match was unsuccessful and false if so.
-/// On entry to the function the "OverallLeftShift" is a signed integer value
-/// indicating the number of bytes that the subexpression is later shifted. For
-/// example, if the expression is later right shifted by 16 bits, the
-/// OverallLeftShift value would be -2 on entry. This is used to specify which
-/// byte of ByteValues is actually being set.
-///
-/// Similarly, ByteMask is a bitmask where a bit is clear if its corresponding
-/// byte is masked to zero by a user. For example, in (X & 255), X will be
-/// processed with a bytemask of 1. Because bytemask is 32-bits, this limits
-/// this function to working on up to 32-byte (256 bit) values. ByteMask is
-/// always in the local (OverallLeftShift) coordinate space.
-///
-static bool CollectBSwapParts(Value *V, int OverallLeftShift, uint32_t ByteMask,
- SmallVector<Value*, 8> &ByteValues) {
- if (Instruction *I = dyn_cast<Instruction>(V)) {
- // If this is an or instruction, it may be an inner node of the bswap.
- if (I->getOpcode() == Instruction::Or) {
- return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask,
- ByteValues) ||
- CollectBSwapParts(I->getOperand(1), OverallLeftShift, ByteMask,
- ByteValues);
- }
-
- // If this is a logical shift by a constant multiple of 8, recurse with
- // OverallLeftShift and ByteMask adjusted.
- if (I->isLogicalShift() && isa<ConstantInt>(I->getOperand(1))) {
- unsigned ShAmt =
- cast<ConstantInt>(I->getOperand(1))->getLimitedValue(~0U);
- // Ensure the shift amount is defined and of a byte value.
- if ((ShAmt & 7) || (ShAmt > 8*ByteValues.size()))
- return true;
-
- unsigned ByteShift = ShAmt >> 3;
- if (I->getOpcode() == Instruction::Shl) {
- // X << 2 -> collect(X, +2)
- OverallLeftShift += ByteShift;
- ByteMask >>= ByteShift;
- } else {
- // X >>u 2 -> collect(X, -2)
- OverallLeftShift -= ByteShift;
- ByteMask <<= ByteShift;
- ByteMask &= (~0U >> (32-ByteValues.size()));
- }
-
- if (OverallLeftShift >= (int)ByteValues.size()) return true;
- if (OverallLeftShift <= -(int)ByteValues.size()) return true;
-
- return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask,
- ByteValues);
- }
-
- // If this is a logical 'and' with a mask that clears bytes, clear the
- // corresponding bytes in ByteMask.
- if (I->getOpcode() == Instruction::And &&
- isa<ConstantInt>(I->getOperand(1))) {
- // Scan every byte of the and mask, seeing if the byte is either 0 or 255.
- unsigned NumBytes = ByteValues.size();
- APInt Byte(I->getType()->getPrimitiveSizeInBits(), 255);
- const APInt &AndMask = cast<ConstantInt>(I->getOperand(1))->getValue();
-
- for (unsigned i = 0; i != NumBytes; ++i, Byte <<= 8) {
- // If this byte is masked out by a later operation, we don't care what
- // the and mask is.
- if ((ByteMask & (1 << i)) == 0)
- continue;
-
- // If the AndMask is all zeros for this byte, clear the bit.
- APInt MaskB = AndMask & Byte;
- if (MaskB == 0) {
- ByteMask &= ~(1U << i);
- continue;
- }
-
- // If the AndMask is not all ones for this byte, it's not a bytezap.
- if (MaskB != Byte)
- return true;
-
- // Otherwise, this byte is kept.
- }
-
- return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask,
- ByteValues);
- }
- }
-
- // Okay, we got to something that isn't a shift, 'or' or 'and'. This must be
- // the input value to the bswap. Some observations: 1) if more than one byte
- // is demanded from this input, then it could not be successfully assembled
- // into a byteswap. At least one of the two bytes would not be aligned with
- // their ultimate destination.
- if (!isPowerOf2_32(ByteMask)) return true;
- unsigned InputByteNo = CountTrailingZeros_32(ByteMask);
-
- // 2) The input and ultimate destinations must line up: if byte 3 of an i32
- // is demanded, it needs to go into byte 0 of the result. This means that the
- // byte needs to be shifted until it lands in the right byte bucket. The
- // shift amount depends on the position: if the byte is coming from the high
- // part of the value (e.g. byte 3) then it must be shifted right. If from the
- // low part, it must be shifted left.
- unsigned DestByteNo = InputByteNo + OverallLeftShift;
- if (InputByteNo < ByteValues.size()/2) {
- if (ByteValues.size()-1-DestByteNo != InputByteNo)
- return true;
- } else {
- if (ByteValues.size()-1-DestByteNo != InputByteNo)
- return true;
- }
-
- // If the destination byte value is already defined, the values are or'd
- // together, which isn't a bswap (unless it's an or of the same bits).
- if (ByteValues[DestByteNo] && ByteValues[DestByteNo] != V)
- return true;
- ByteValues[DestByteNo] = V;
- return false;
-}
-
-/// MatchBSwap - Given an OR instruction, check to see if this is a bswap idiom.
-/// If so, insert the new bswap intrinsic and return it.
-Instruction *InstCombiner::MatchBSwap(BinaryOperator &I) {
- const IntegerType *ITy = dyn_cast<IntegerType>(I.getType());
- if (!ITy || ITy->getBitWidth() % 16 ||
- // ByteMask only allows up to 32-byte values.
- ITy->getBitWidth() > 32*8)
- return 0; // Can only bswap pairs of bytes. Can't do vectors.
-
- /// ByteValues - For each byte of the result, we keep track of which value
- /// defines each byte.
- SmallVector<Value*, 8> ByteValues;
- ByteValues.resize(ITy->getBitWidth()/8);
-
- // Try to find all the pieces corresponding to the bswap.
- uint32_t ByteMask = ~0U >> (32-ByteValues.size());
- if (CollectBSwapParts(&I, 0, ByteMask, ByteValues))
- return 0;
-
- // Check to see if all of the bytes come from the same value.
- Value *V = ByteValues[0];
- if (V == 0) return 0; // Didn't find a byte? Must be zero.
-
- // Check to make sure that all of the bytes come from the same value.
- for (unsigned i = 1, e = ByteValues.size(); i != e; ++i)
- if (ByteValues[i] != V)
- return 0;
- const Type *Tys[] = { ITy };
- Module *M = I.getParent()->getParent()->getParent();
- Function *F = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
- return CallInst::Create(F, V);
-}
-
-/// MatchSelectFromAndOr - We have an expression of the form (A&C)|(B&D). Check
-/// If A is (cond?-1:0) and either B or D is ~(cond?-1,0) or (cond?0,-1), then
-/// we can simplify this expression to "cond ? C : D or B".
-static Instruction *MatchSelectFromAndOr(Value *A, Value *B,
- Value *C, Value *D) {
- // If A is not a select of -1/0, this cannot match.
- Value *Cond = 0;
- if (!match(A, m_SelectCst<-1, 0>(m_Value(Cond))))
- return 0;
-
- // ((cond?-1:0)&C) | (B&(cond?0:-1)) -> cond ? C : B.
- if (match(D, m_SelectCst<0, -1>(m_Specific(Cond))))
- return SelectInst::Create(Cond, C, B);
- if (match(D, m_Not(m_SelectCst<-1, 0>(m_Specific(Cond)))))
- return SelectInst::Create(Cond, C, B);
- // ((cond?-1:0)&C) | ((cond?0:-1)&D) -> cond ? C : D.
- if (match(B, m_SelectCst<0, -1>(m_Specific(Cond))))
- return SelectInst::Create(Cond, C, D);
- if (match(B, m_Not(m_SelectCst<-1, 0>(m_Specific(Cond)))))
- return SelectInst::Create(Cond, C, D);
- return 0;
-}
-
-/// FoldOrOfICmps - Fold (icmp)|(icmp) if possible.
-Instruction *InstCombiner::FoldOrOfICmps(Instruction &I,
- ICmpInst *LHS, ICmpInst *RHS) {
- Value *Val, *Val2;
- ConstantInt *LHSCst, *RHSCst;
- ICmpInst::Predicate LHSCC, RHSCC;
-
- // This only handles icmp of constants: (icmp1 A, C1) | (icmp2 B, C2).
- if (!match(LHS, m_ICmp(LHSCC, m_Value(Val), m_ConstantInt(LHSCst))) ||
- !match(RHS, m_ICmp(RHSCC, m_Value(Val2), m_ConstantInt(RHSCst))))
- return 0;
-
-
- // (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0)
- if (LHSCst == RHSCst && LHSCC == RHSCC &&
- LHSCC == ICmpInst::ICMP_NE && LHSCst->isZero()) {
- Value *NewOr = Builder->CreateOr(Val, Val2);
- return new ICmpInst(LHSCC, NewOr, LHSCst);
- }
-
- // From here on, we only handle:
- // (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
- if (Val != Val2) return 0;
-
- // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
- if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE ||
- RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE ||
- LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE ||
- RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE)
- return 0;
-
- // We can't fold (ugt x, C) | (sgt x, C2).
- if (!PredicatesFoldable(LHSCC, RHSCC))
- return 0;
-
- // Ensure that the larger constant is on the RHS.
- bool ShouldSwap;
- if (CmpInst::isSigned(LHSCC) ||
- (ICmpInst::isEquality(LHSCC) &&
- CmpInst::isSigned(RHSCC)))
- ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue());
- else
- ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue());
-
- if (ShouldSwap) {
- std::swap(LHS, RHS);
- std::swap(LHSCst, RHSCst);
- std::swap(LHSCC, RHSCC);
- }
-
- // At this point, we know we have have two icmp instructions
- // comparing a value against two constants and or'ing the result
- // together. Because of the above check, we know that we only have
- // ICMP_EQ, ICMP_NE, ICMP_LT, and ICMP_GT here. We also know (from the
- // FoldICmpLogical check above), that the two constants are not
- // equal.
- assert(LHSCst != RHSCst && "Compares not folded above?");
-
- switch (LHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ:
- if (LHSCst == SubOne(RHSCst)) {
- // (X == 13 | X == 14) -> X-13 <u 2
- Constant *AddCST = ConstantExpr::getNeg(LHSCst);
- Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off");
- AddCST = ConstantExpr::getSub(AddOne(RHSCst), LHSCst);
- return new ICmpInst(ICmpInst::ICMP_ULT, Add, AddCST);
- }
- break; // (X == 13 | X == 15) -> no change
- case ICmpInst::ICMP_UGT: // (X == 13 | X u> 14) -> no change
- case ICmpInst::ICMP_SGT: // (X == 13 | X s> 14) -> no change
- break;
- case ICmpInst::ICMP_NE: // (X == 13 | X != 15) -> X != 15
- case ICmpInst::ICMP_ULT: // (X == 13 | X u< 15) -> X u< 15
- case ICmpInst::ICMP_SLT: // (X == 13 | X s< 15) -> X s< 15
- return ReplaceInstUsesWith(I, RHS);
- }
- break;
- case ICmpInst::ICMP_NE:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ: // (X != 13 | X == 15) -> X != 13
- case ICmpInst::ICMP_UGT: // (X != 13 | X u> 15) -> X != 13
- case ICmpInst::ICMP_SGT: // (X != 13 | X s> 15) -> X != 13
- return ReplaceInstUsesWith(I, LHS);
- case ICmpInst::ICMP_NE: // (X != 13 | X != 15) -> true
- case ICmpInst::ICMP_ULT: // (X != 13 | X u< 15) -> true
- case ICmpInst::ICMP_SLT: // (X != 13 | X s< 15) -> true
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
- }
- break;
- case ICmpInst::ICMP_ULT:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ: // (X u< 13 | X == 14) -> no change
- break;
- case ICmpInst::ICMP_UGT: // (X u< 13 | X u> 15) -> (X-13) u> 2
- // If RHSCst is [us]MAXINT, it is always false. Not handling
- // this can cause overflow.
- if (RHSCst->isMaxValue(false))
- return ReplaceInstUsesWith(I, LHS);
- return InsertRangeTest(Val, LHSCst, AddOne(RHSCst),
- false, false, I);
- case ICmpInst::ICMP_SGT: // (X u< 13 | X s> 15) -> no change
- break;
- case ICmpInst::ICMP_NE: // (X u< 13 | X != 15) -> X != 15
- case ICmpInst::ICMP_ULT: // (X u< 13 | X u< 15) -> X u< 15
- return ReplaceInstUsesWith(I, RHS);
- case ICmpInst::ICMP_SLT: // (X u< 13 | X s< 15) -> no change
- break;
- }
- break;
- case ICmpInst::ICMP_SLT:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ: // (X s< 13 | X == 14) -> no change
- break;
- case ICmpInst::ICMP_SGT: // (X s< 13 | X s> 15) -> (X-13) s> 2
- // If RHSCst is [us]MAXINT, it is always false. Not handling
- // this can cause overflow.
- if (RHSCst->isMaxValue(true))
- return ReplaceInstUsesWith(I, LHS);
- return InsertRangeTest(Val, LHSCst, AddOne(RHSCst),
- true, false, I);
- case ICmpInst::ICMP_UGT: // (X s< 13 | X u> 15) -> no change
- break;
- case ICmpInst::ICMP_NE: // (X s< 13 | X != 15) -> X != 15
- case ICmpInst::ICMP_SLT: // (X s< 13 | X s< 15) -> X s< 15
- return ReplaceInstUsesWith(I, RHS);
- case ICmpInst::ICMP_ULT: // (X s< 13 | X u< 15) -> no change
- break;
- }
- break;
- case ICmpInst::ICMP_UGT:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ: // (X u> 13 | X == 15) -> X u> 13
- case ICmpInst::ICMP_UGT: // (X u> 13 | X u> 15) -> X u> 13
- return ReplaceInstUsesWith(I, LHS);
- case ICmpInst::ICMP_SGT: // (X u> 13 | X s> 15) -> no change
- break;
- case ICmpInst::ICMP_NE: // (X u> 13 | X != 15) -> true
- case ICmpInst::ICMP_ULT: // (X u> 13 | X u< 15) -> true
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
- case ICmpInst::ICMP_SLT: // (X u> 13 | X s< 15) -> no change
- break;
- }
- break;
- case ICmpInst::ICMP_SGT:
- switch (RHSCC) {
- default: llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ: // (X s> 13 | X == 15) -> X > 13
- case ICmpInst::ICMP_SGT: // (X s> 13 | X s> 15) -> X > 13
- return ReplaceInstUsesWith(I, LHS);
- case ICmpInst::ICMP_UGT: // (X s> 13 | X u> 15) -> no change
- break;
- case ICmpInst::ICMP_NE: // (X s> 13 | X != 15) -> true
- case ICmpInst::ICMP_SLT: // (X s> 13 | X s< 15) -> true
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
- case ICmpInst::ICMP_ULT: // (X s> 13 | X u< 15) -> no change
- break;
- }
- break;
- }
- return 0;
-}
-
-Instruction *InstCombiner::FoldOrOfFCmps(Instruction &I, FCmpInst *LHS,
- FCmpInst *RHS) {
- if (LHS->getPredicate() == FCmpInst::FCMP_UNO &&
- RHS->getPredicate() == FCmpInst::FCMP_UNO &&
- LHS->getOperand(0)->getType() == RHS->getOperand(0)->getType()) {
- if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
- if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
- // If either of the constants are nans, then the whole thing returns
- // true.
- if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
-
- // Otherwise, no need to compare the two constants, compare the
- // rest.
- return new FCmpInst(FCmpInst::FCMP_UNO,
- LHS->getOperand(0), RHS->getOperand(0));
- }
-
- // Handle vector zeros. This occurs because the canonical form of
- // "fcmp uno x,x" is "fcmp uno x, 0".
- if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
- isa<ConstantAggregateZero>(RHS->getOperand(1)))
- return new FCmpInst(FCmpInst::FCMP_UNO,
- LHS->getOperand(0), RHS->getOperand(0));
-
- return 0;
- }
-
- Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
- Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
- FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
-
- if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
- // Swap RHS operands to match LHS.
- Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
- std::swap(Op1LHS, Op1RHS);
- }
- if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) {
- // Simplify (fcmp cc0 x, y) | (fcmp cc1 x, y).
- if (Op0CC == Op1CC)
- return new FCmpInst((FCmpInst::Predicate)Op0CC,
- Op0LHS, Op0RHS);
- if (Op0CC == FCmpInst::FCMP_TRUE || Op1CC == FCmpInst::FCMP_TRUE)
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
- if (Op0CC == FCmpInst::FCMP_FALSE)
- return ReplaceInstUsesWith(I, RHS);
- if (Op1CC == FCmpInst::FCMP_FALSE)
- return ReplaceInstUsesWith(I, LHS);
- bool Op0Ordered;
- bool Op1Ordered;
- unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
- unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
- if (Op0Ordered == Op1Ordered) {
- // If both are ordered or unordered, return a new fcmp with
- // or'ed predicates.
- Value *RV = getFCmpValue(Op0Ordered, Op0Pred|Op1Pred, Op0LHS, Op0RHS);
- if (Instruction *I = dyn_cast<Instruction>(RV))
- return I;
- // Otherwise, it's a constant boolean value...
- return ReplaceInstUsesWith(I, RV);
- }
- }
- return 0;
-}
-
-/// FoldOrWithConstants - This helper function folds:
-///
-/// ((A | B) & C1) | (B & C2)
-///
-/// into:
-///
-/// (A & C1) | B
-///
-/// when the XOR of the two constants is "all ones" (-1).
-Instruction *InstCombiner::FoldOrWithConstants(BinaryOperator &I, Value *Op,
- Value *A, Value *B, Value *C) {
- ConstantInt *CI1 = dyn_cast<ConstantInt>(C);
- if (!CI1) return 0;
-
- Value *V1 = 0;
- ConstantInt *CI2 = 0;
- if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2)))) return 0;
-
- APInt Xor = CI1->getValue() ^ CI2->getValue();
- if (!Xor.isAllOnesValue()) return 0;
-
- if (V1 == A || V1 == B) {
- Value *NewOp = Builder->CreateAnd((V1 == A) ? B : A, CI1);
- return BinaryOperator::CreateOr(NewOp, V1);
- }
-
- return 0;
-}
-
-Instruction *InstCombiner::visitOr(BinaryOperator &I) {
- bool Changed = SimplifyCommutative(I);
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- if (Value *V = SimplifyOrInst(Op0, Op1, TD))
- return ReplaceInstUsesWith(I, V);
-
-
- // See if we can simplify any instructions used by the instruction whose sole
- // purpose is to compute bits we don't care about.
- if (SimplifyDemandedInstructionBits(I))
- return &I;
-
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- ConstantInt *C1 = 0; Value *X = 0;
- // (X & C1) | C2 --> (X | C2) & (C1|C2)
- if (match(Op0, m_And(m_Value(X), m_ConstantInt(C1))) &&
- isOnlyUse(Op0)) {
- Value *Or = Builder->CreateOr(X, RHS);
- Or->takeName(Op0);
- return BinaryOperator::CreateAnd(Or,
- ConstantInt::get(I.getContext(),
- RHS->getValue() | C1->getValue()));
- }
-
- // (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2)
- if (match(Op0, m_Xor(m_Value(X), m_ConstantInt(C1))) &&
- isOnlyUse(Op0)) {
- Value *Or = Builder->CreateOr(X, RHS);
- Or->takeName(Op0);
- return BinaryOperator::CreateXor(Or,
- ConstantInt::get(I.getContext(),
- C1->getValue() & ~RHS->getValue()));
- }
-
- // Try to fold constant and into select arguments.
- if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
- if (isa<PHINode>(Op0))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
- }
-
- Value *A = 0, *B = 0;
- ConstantInt *C1 = 0, *C2 = 0;
-
- // (A | B) | C and A | (B | C) -> bswap if possible.
- // (A >> B) | (C << D) and (A << B) | (B >> C) -> bswap if possible.
- if (match(Op0, m_Or(m_Value(), m_Value())) ||
- match(Op1, m_Or(m_Value(), m_Value())) ||
- (match(Op0, m_Shift(m_Value(), m_Value())) &&
- match(Op1, m_Shift(m_Value(), m_Value())))) {
- if (Instruction *BSwap = MatchBSwap(I))
- return BSwap;
- }
-
- // (X^C)|Y -> (X|Y)^C iff Y&C == 0
- if (Op0->hasOneUse() &&
- match(Op0, m_Xor(m_Value(A), m_ConstantInt(C1))) &&
- MaskedValueIsZero(Op1, C1->getValue())) {
- Value *NOr = Builder->CreateOr(A, Op1);
- NOr->takeName(Op0);
- return BinaryOperator::CreateXor(NOr, C1);
- }
-
- // Y|(X^C) -> (X|Y)^C iff Y&C == 0
- if (Op1->hasOneUse() &&
- match(Op1, m_Xor(m_Value(A), m_ConstantInt(C1))) &&
- MaskedValueIsZero(Op0, C1->getValue())) {
- Value *NOr = Builder->CreateOr(A, Op0);
- NOr->takeName(Op0);
- return BinaryOperator::CreateXor(NOr, C1);
- }
-
- // (A & C)|(B & D)
- Value *C = 0, *D = 0;
- if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
- match(Op1, m_And(m_Value(B), m_Value(D)))) {
- Value *V1 = 0, *V2 = 0, *V3 = 0;
- C1 = dyn_cast<ConstantInt>(C);
- C2 = dyn_cast<ConstantInt>(D);
- if (C1 && C2) { // (A & C1)|(B & C2)
- // If we have: ((V + N) & C1) | (V & C2)
- // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
- // replace with V+N.
- if (C1->getValue() == ~C2->getValue()) {
- if ((C2->getValue() & (C2->getValue()+1)) == 0 && // C2 == 0+1+
- match(A, m_Add(m_Value(V1), m_Value(V2)))) {
- // Add commutes, try both ways.
- if (V1 == B && MaskedValueIsZero(V2, C2->getValue()))
- return ReplaceInstUsesWith(I, A);
- if (V2 == B && MaskedValueIsZero(V1, C2->getValue()))
- return ReplaceInstUsesWith(I, A);
- }
- // Or commutes, try both ways.
- if ((C1->getValue() & (C1->getValue()+1)) == 0 &&
- match(B, m_Add(m_Value(V1), m_Value(V2)))) {
- // Add commutes, try both ways.
- if (V1 == A && MaskedValueIsZero(V2, C1->getValue()))
- return ReplaceInstUsesWith(I, B);
- if (V2 == A && MaskedValueIsZero(V1, C1->getValue()))
- return ReplaceInstUsesWith(I, B);
- }
- }
-
- // ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2)
- // iff (C1&C2) == 0 and (N&~C1) == 0
- if ((C1->getValue() & C2->getValue()) == 0) {
- if (match(A, m_Or(m_Value(V1), m_Value(V2))) &&
- ((V1 == B && MaskedValueIsZero(V2, ~C1->getValue())) || // (V|N)
- (V2 == B && MaskedValueIsZero(V1, ~C1->getValue())))) // (N|V)
- return BinaryOperator::CreateAnd(A,
- ConstantInt::get(A->getContext(),
- C1->getValue()|C2->getValue()));
- // Or commutes, try both ways.
- if (match(B, m_Or(m_Value(V1), m_Value(V2))) &&
- ((V1 == A && MaskedValueIsZero(V2, ~C2->getValue())) || // (V|N)
- (V2 == A && MaskedValueIsZero(V1, ~C2->getValue())))) // (N|V)
- return BinaryOperator::CreateAnd(B,
- ConstantInt::get(B->getContext(),
- C1->getValue()|C2->getValue()));
- }
- }
-
- // Check to see if we have any common things being and'ed. If so, find the
- // terms for V1 & (V2|V3).
- if (isOnlyUse(Op0) || isOnlyUse(Op1)) {
- V1 = 0;
- if (A == B) // (A & C)|(A & D) == A & (C|D)
- V1 = A, V2 = C, V3 = D;
- else if (A == D) // (A & C)|(B & A) == A & (B|C)
- V1 = A, V2 = B, V3 = C;
- else if (C == B) // (A & C)|(C & D) == C & (A|D)
- V1 = C, V2 = A, V3 = D;
- else if (C == D) // (A & C)|(B & C) == C & (A|B)
- V1 = C, V2 = A, V3 = B;
-
- if (V1) {
- Value *Or = Builder->CreateOr(V2, V3, "tmp");
- return BinaryOperator::CreateAnd(V1, Or);
- }
- }
-
- // (A & (C0?-1:0)) | (B & ~(C0?-1:0)) -> C0 ? A : B, and commuted variants
- if (Instruction *Match = MatchSelectFromAndOr(A, B, C, D))
- return Match;
- if (Instruction *Match = MatchSelectFromAndOr(B, A, D, C))
- return Match;
- if (Instruction *Match = MatchSelectFromAndOr(C, B, A, D))
- return Match;
- if (Instruction *Match = MatchSelectFromAndOr(D, A, B, C))
- return Match;
-
- // ((A&~B)|(~A&B)) -> A^B
- if ((match(C, m_Not(m_Specific(D))) &&
- match(B, m_Not(m_Specific(A)))))
- return BinaryOperator::CreateXor(A, D);
- // ((~B&A)|(~A&B)) -> A^B
- if ((match(A, m_Not(m_Specific(D))) &&
- match(B, m_Not(m_Specific(C)))))
- return BinaryOperator::CreateXor(C, D);
- // ((A&~B)|(B&~A)) -> A^B
- if ((match(C, m_Not(m_Specific(B))) &&
- match(D, m_Not(m_Specific(A)))))
- return BinaryOperator::CreateXor(A, B);
- // ((~B&A)|(B&~A)) -> A^B
- if ((match(A, m_Not(m_Specific(B))) &&
- match(D, m_Not(m_Specific(C)))))
- return BinaryOperator::CreateXor(C, B);
- }
-
- // (X >> Z) | (Y >> Z) -> (X|Y) >> Z for all shifts.
- if (BinaryOperator *SI1 = dyn_cast<BinaryOperator>(Op1)) {
- if (BinaryOperator *SI0 = dyn_cast<BinaryOperator>(Op0))
- if (SI0->isShift() && SI0->getOpcode() == SI1->getOpcode() &&
- SI0->getOperand(1) == SI1->getOperand(1) &&
- (SI0->hasOneUse() || SI1->hasOneUse())) {
- Value *NewOp = Builder->CreateOr(SI0->getOperand(0), SI1->getOperand(0),
- SI0->getName());
- return BinaryOperator::Create(SI1->getOpcode(), NewOp,
- SI1->getOperand(1));
- }
- }
-
- // ((A|B)&1)|(B&-2) -> (A&1) | B
- if (match(Op0, m_And(m_Or(m_Value(A), m_Value(B)), m_Value(C))) ||
- match(Op0, m_And(m_Value(C), m_Or(m_Value(A), m_Value(B))))) {
- Instruction *Ret = FoldOrWithConstants(I, Op1, A, B, C);
- if (Ret) return Ret;
- }
- // (B&-2)|((A|B)&1) -> (A&1) | B
- if (match(Op1, m_And(m_Or(m_Value(A), m_Value(B)), m_Value(C))) ||
- match(Op1, m_And(m_Value(C), m_Or(m_Value(A), m_Value(B))))) {
- Instruction *Ret = FoldOrWithConstants(I, Op0, A, B, C);
- if (Ret) return Ret;
- }
-
- // (~A | ~B) == (~(A & B)) - De Morgan's Law
- if (Value *Op0NotVal = dyn_castNotVal(Op0))
- if (Value *Op1NotVal = dyn_castNotVal(Op1))
- if (Op0->hasOneUse() && Op1->hasOneUse()) {
- Value *And = Builder->CreateAnd(Op0NotVal, Op1NotVal,
- I.getName()+".demorgan");
- return BinaryOperator::CreateNot(And);
- }
-
- // (icmp1 A, B) | (icmp2 A, B) --> (icmp3 A, B)
- if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1))) {
- if (Instruction *R = AssociativeOpt(I, FoldICmpLogical(*this, RHS)))
- return R;
-
- if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0)))
- if (Instruction *Res = FoldOrOfICmps(I, LHS, RHS))
- return Res;
- }
-
- // fold (or (cast A), (cast B)) -> (cast (or A, B))
- if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
- if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
- if (Op0C->getOpcode() == Op1C->getOpcode()) {// same cast kind ?
- if (!isa<ICmpInst>(Op0C->getOperand(0)) ||
- !isa<ICmpInst>(Op1C->getOperand(0))) {
- const Type *SrcTy = Op0C->getOperand(0)->getType();
- if (SrcTy == Op1C->getOperand(0)->getType() &&
- SrcTy->isIntOrIntVector() &&
- // Only do this if the casts both really cause code to be
- // generated.
- ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0),
- I.getType()) &&
- ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0),
- I.getType())) {
- Value *NewOp = Builder->CreateOr(Op0C->getOperand(0),
- Op1C->getOperand(0), I.getName());
- return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
- }
- }
- }
- }
-
-
- // (fcmp uno x, c) | (fcmp uno y, c) -> (fcmp uno x, y)
- if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0))) {
- if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
- if (Instruction *Res = FoldOrOfFCmps(I, LHS, RHS))
- return Res;
- }
-
- return Changed ? &I : 0;
-}
-
-namespace {
-
-// XorSelf - Implements: X ^ X --> 0
-struct XorSelf {
- Value *RHS;
- XorSelf(Value *rhs) : RHS(rhs) {}
- bool shouldApply(Value *LHS) const { return LHS == RHS; }
- Instruction *apply(BinaryOperator &Xor) const {
- return &Xor;
- }
-};
-
-}
-
-Instruction *InstCombiner::visitXor(BinaryOperator &I) {
- bool Changed = SimplifyCommutative(I);
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- if (isa<UndefValue>(Op1)) {
- if (isa<UndefValue>(Op0))
- // Handle undef ^ undef -> 0 special case. This is a common
- // idiom (misuse).
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- return ReplaceInstUsesWith(I, Op1); // X ^ undef -> undef
- }
-
- // xor X, X = 0, even if X is nested in a sequence of Xor's.
- if (Instruction *Result = AssociativeOpt(I, XorSelf(Op1))) {
- assert(Result == &I && "AssociativeOpt didn't work?"); Result=Result;
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- }
-
- // See if we can simplify any instructions used by the instruction whose sole
- // purpose is to compute bits we don't care about.
- if (SimplifyDemandedInstructionBits(I))
- return &I;
- if (isa<VectorType>(I.getType()))
- if (isa<ConstantAggregateZero>(Op1))
- return ReplaceInstUsesWith(I, Op0); // X ^ <0,0> -> X
-
- // Is this a ~ operation?
- if (Value *NotOp = dyn_castNotVal(&I)) {
- if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(NotOp)) {
- if (Op0I->getOpcode() == Instruction::And ||
- Op0I->getOpcode() == Instruction::Or) {
- // ~(~X & Y) --> (X | ~Y) - De Morgan's Law
- // ~(~X | Y) === (X & ~Y) - De Morgan's Law
- if (dyn_castNotVal(Op0I->getOperand(1)))
- Op0I->swapOperands();
- if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0))) {
- Value *NotY =
- Builder->CreateNot(Op0I->getOperand(1),
- Op0I->getOperand(1)->getName()+".not");
- if (Op0I->getOpcode() == Instruction::And)
- return BinaryOperator::CreateOr(Op0NotVal, NotY);
- return BinaryOperator::CreateAnd(Op0NotVal, NotY);
- }
-
- // ~(X & Y) --> (~X | ~Y) - De Morgan's Law
- // ~(X | Y) === (~X & ~Y) - De Morgan's Law
- if (isFreeToInvert(Op0I->getOperand(0)) &&
- isFreeToInvert(Op0I->getOperand(1))) {
- Value *NotX =
- Builder->CreateNot(Op0I->getOperand(0), "notlhs");
- Value *NotY =
- Builder->CreateNot(Op0I->getOperand(1), "notrhs");
- if (Op0I->getOpcode() == Instruction::And)
- return BinaryOperator::CreateOr(NotX, NotY);
- return BinaryOperator::CreateAnd(NotX, NotY);
- }
- }
- }
- }
-
-
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- if (RHS->isOne() && Op0->hasOneUse()) {
- // xor (cmp A, B), true = not (cmp A, B) = !cmp A, B
- if (ICmpInst *ICI = dyn_cast<ICmpInst>(Op0))
- return new ICmpInst(ICI->getInversePredicate(),
- ICI->getOperand(0), ICI->getOperand(1));
-
- if (FCmpInst *FCI = dyn_cast<FCmpInst>(Op0))
- return new FCmpInst(FCI->getInversePredicate(),
- FCI->getOperand(0), FCI->getOperand(1));
- }
-
- // fold (xor(zext(cmp)), 1) and (xor(sext(cmp)), -1) to ext(!cmp).
- if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
- if (CmpInst *CI = dyn_cast<CmpInst>(Op0C->getOperand(0))) {
- if (CI->hasOneUse() && Op0C->hasOneUse()) {
- Instruction::CastOps Opcode = Op0C->getOpcode();
- if ((Opcode == Instruction::ZExt || Opcode == Instruction::SExt) &&
- (RHS == ConstantExpr::getCast(Opcode,
- ConstantInt::getTrue(I.getContext()),
- Op0C->getDestTy()))) {
- CI->setPredicate(CI->getInversePredicate());
- return CastInst::Create(Opcode, CI, Op0C->getType());
- }
- }
- }
- }
-
- if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
- // ~(c-X) == X-c-1 == X+(-c-1)
- if (Op0I->getOpcode() == Instruction::Sub && RHS->isAllOnesValue())
- if (Constant *Op0I0C = dyn_cast<Constant>(Op0I->getOperand(0))) {
- Constant *NegOp0I0C = ConstantExpr::getNeg(Op0I0C);
- Constant *ConstantRHS = ConstantExpr::getSub(NegOp0I0C,
- ConstantInt::get(I.getType(), 1));
- return BinaryOperator::CreateAdd(Op0I->getOperand(1), ConstantRHS);
- }
-
- if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
- if (Op0I->getOpcode() == Instruction::Add) {
- // ~(X-c) --> (-c-1)-X
- if (RHS->isAllOnesValue()) {
- Constant *NegOp0CI = ConstantExpr::getNeg(Op0CI);
- return BinaryOperator::CreateSub(
- ConstantExpr::getSub(NegOp0CI,
- ConstantInt::get(I.getType(), 1)),
- Op0I->getOperand(0));
- } else if (RHS->getValue().isSignBit()) {
- // (X + C) ^ signbit -> (X + C + signbit)
- Constant *C = ConstantInt::get(I.getContext(),
- RHS->getValue() + Op0CI->getValue());
- return BinaryOperator::CreateAdd(Op0I->getOperand(0), C);
-
- }
- } else if (Op0I->getOpcode() == Instruction::Or) {
- // (X|C1)^C2 -> X^(C1|C2) iff X&~C1 == 0
- if (MaskedValueIsZero(Op0I->getOperand(0), Op0CI->getValue())) {
- Constant *NewRHS = ConstantExpr::getOr(Op0CI, RHS);
- // Anything in both C1 and C2 is known to be zero, remove it from
- // NewRHS.
- Constant *CommonBits = ConstantExpr::getAnd(Op0CI, RHS);
- NewRHS = ConstantExpr::getAnd(NewRHS,
- ConstantExpr::getNot(CommonBits));
- Worklist.Add(Op0I);
- I.setOperand(0, Op0I->getOperand(0));
- I.setOperand(1, NewRHS);
- return &I;
- }
- }
- }
- }
-
- // Try to fold constant and into select arguments.
- if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
- if (isa<PHINode>(Op0))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
- }
-
- if (Value *X = dyn_castNotVal(Op0)) // ~A ^ A == -1
- if (X == Op1)
- return ReplaceInstUsesWith(I, Constant::getAllOnesValue(I.getType()));
-
- if (Value *X = dyn_castNotVal(Op1)) // A ^ ~A == -1
- if (X == Op0)
- return ReplaceInstUsesWith(I, Constant::getAllOnesValue(I.getType()));
-
-
- BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1);
- if (Op1I) {
- Value *A, *B;
- if (match(Op1I, m_Or(m_Value(A), m_Value(B)))) {
- if (A == Op0) { // B^(B|A) == (A|B)^B
- Op1I->swapOperands();
- I.swapOperands();
- std::swap(Op0, Op1);
- } else if (B == Op0) { // B^(A|B) == (A|B)^B
- I.swapOperands(); // Simplified below.
- std::swap(Op0, Op1);
- }
- } else if (match(Op1I, m_Xor(m_Specific(Op0), m_Value(B)))) {
- return ReplaceInstUsesWith(I, B); // A^(A^B) == B
- } else if (match(Op1I, m_Xor(m_Value(A), m_Specific(Op0)))) {
- return ReplaceInstUsesWith(I, A); // A^(B^A) == B
- } else if (match(Op1I, m_And(m_Value(A), m_Value(B))) &&
- Op1I->hasOneUse()){
- if (A == Op0) { // A^(A&B) -> A^(B&A)
- Op1I->swapOperands();
- std::swap(A, B);
- }
- if (B == Op0) { // A^(B&A) -> (B&A)^A
- I.swapOperands(); // Simplified below.
- std::swap(Op0, Op1);
- }
- }
- }
-
- BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0);
- if (Op0I) {
- Value *A, *B;
- if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
- Op0I->hasOneUse()) {
- if (A == Op1) // (B|A)^B == (A|B)^B
- std::swap(A, B);
- if (B == Op1) // (A|B)^B == A & ~B
- return BinaryOperator::CreateAnd(A, Builder->CreateNot(Op1, "tmp"));
- } else if (match(Op0I, m_Xor(m_Specific(Op1), m_Value(B)))) {
- return ReplaceInstUsesWith(I, B); // (A^B)^A == B
- } else if (match(Op0I, m_Xor(m_Value(A), m_Specific(Op1)))) {
- return ReplaceInstUsesWith(I, A); // (B^A)^A == B
- } else if (match(Op0I, m_And(m_Value(A), m_Value(B))) &&
- Op0I->hasOneUse()){
- if (A == Op1) // (A&B)^A -> (B&A)^A
- std::swap(A, B);
- if (B == Op1 && // (B&A)^A == ~B & A
- !isa<ConstantInt>(Op1)) { // Canonical form is (B&C)^C
- return BinaryOperator::CreateAnd(Builder->CreateNot(A, "tmp"), Op1);
- }
- }
- }
-
- // (X >> Z) ^ (Y >> Z) -> (X^Y) >> Z for all shifts.
- if (Op0I && Op1I && Op0I->isShift() &&
- Op0I->getOpcode() == Op1I->getOpcode() &&
- Op0I->getOperand(1) == Op1I->getOperand(1) &&
- (Op1I->hasOneUse() || Op1I->hasOneUse())) {
- Value *NewOp =
- Builder->CreateXor(Op0I->getOperand(0), Op1I->getOperand(0),
- Op0I->getName());
- return BinaryOperator::Create(Op1I->getOpcode(), NewOp,
- Op1I->getOperand(1));
- }
-
- if (Op0I && Op1I) {
- Value *A, *B, *C, *D;
- // (A & B)^(A | B) -> A ^ B
- if (match(Op0I, m_And(m_Value(A), m_Value(B))) &&
- match(Op1I, m_Or(m_Value(C), m_Value(D)))) {
- if ((A == C && B == D) || (A == D && B == C))
- return BinaryOperator::CreateXor(A, B);
- }
- // (A | B)^(A & B) -> A ^ B
- if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
- match(Op1I, m_And(m_Value(C), m_Value(D)))) {
- if ((A == C && B == D) || (A == D && B == C))
- return BinaryOperator::CreateXor(A, B);
- }
-
- // (A & B)^(C & D)
- if ((Op0I->hasOneUse() || Op1I->hasOneUse()) &&
- match(Op0I, m_And(m_Value(A), m_Value(B))) &&
- match(Op1I, m_And(m_Value(C), m_Value(D)))) {
- // (X & Y)^(X & Y) -> (Y^Z) & X
- Value *X = 0, *Y = 0, *Z = 0;
- if (A == C)
- X = A, Y = B, Z = D;
- else if (A == D)
- X = A, Y = B, Z = C;
- else if (B == C)
- X = B, Y = A, Z = D;
- else if (B == D)
- X = B, Y = A, Z = C;
-
- if (X) {
- Value *NewOp = Builder->CreateXor(Y, Z, Op0->getName());
- return BinaryOperator::CreateAnd(NewOp, X);
- }
- }
- }
-
- // (icmp1 A, B) ^ (icmp2 A, B) --> (icmp3 A, B)
- if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1)))
- if (Instruction *R = AssociativeOpt(I, FoldICmpLogical(*this, RHS)))
- return R;
-
- // fold (xor (cast A), (cast B)) -> (cast (xor A, B))
- if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
- if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
- if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind?
- const Type *SrcTy = Op0C->getOperand(0)->getType();
- if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isInteger() &&
- // Only do this if the casts both really cause code to be generated.
- ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0),
- I.getType()) &&
- ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0),
- I.getType())) {
- Value *NewOp = Builder->CreateXor(Op0C->getOperand(0),
- Op1C->getOperand(0), I.getName());
- return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
- }
- }
- }
-
- return Changed ? &I : 0;
-}
-
-
-Instruction *InstCombiner::visitShl(BinaryOperator &I) {
- return commonShiftTransforms(I);
-}
-
-Instruction *InstCombiner::visitLShr(BinaryOperator &I) {
- return commonShiftTransforms(I);
-}
-
-Instruction *InstCombiner::visitAShr(BinaryOperator &I) {
- if (Instruction *R = commonShiftTransforms(I))
- return R;
-
- Value *Op0 = I.getOperand(0);
-
- // ashr int -1, X = -1 (for any arithmetic shift rights of ~0)
- if (ConstantInt *CSI = dyn_cast<ConstantInt>(Op0))
- if (CSI->isAllOnesValue())
- return ReplaceInstUsesWith(I, CSI);
-
- // See if we can turn a signed shr into an unsigned shr.
- if (MaskedValueIsZero(Op0,
- APInt::getSignBit(I.getType()->getScalarSizeInBits())))
- return BinaryOperator::CreateLShr(Op0, I.getOperand(1));
-
- // Arithmetic shifting an all-sign-bit value is a no-op.
- unsigned NumSignBits = ComputeNumSignBits(Op0);
- if (NumSignBits == Op0->getType()->getScalarSizeInBits())
- return ReplaceInstUsesWith(I, Op0);
-
- return 0;
-}
-
-Instruction *InstCombiner::commonShiftTransforms(BinaryOperator &I) {
- assert(I.getOperand(1)->getType() == I.getOperand(0)->getType());
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
- // shl X, 0 == X and shr X, 0 == X
- // shl 0, X == 0 and shr 0, X == 0
- if (Op1 == Constant::getNullValue(Op1->getType()) ||
- Op0 == Constant::getNullValue(Op0->getType()))
- return ReplaceInstUsesWith(I, Op0);
-
- if (isa<UndefValue>(Op0)) {
- if (I.getOpcode() == Instruction::AShr) // undef >>s X -> undef
- return ReplaceInstUsesWith(I, Op0);
- else // undef << X -> 0, undef >>u X -> 0
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- }
- if (isa<UndefValue>(Op1)) {
- if (I.getOpcode() == Instruction::AShr) // X >>s undef -> X
- return ReplaceInstUsesWith(I, Op0);
- else // X << undef, X >>u undef -> 0
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- }
-
- // See if we can fold away this shift.
- if (SimplifyDemandedInstructionBits(I))
- return &I;
-
- // Try to fold constant and into select arguments.
- if (isa<Constant>(Op0))
- if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
-
- if (ConstantInt *CUI = dyn_cast<ConstantInt>(Op1))
- if (Instruction *Res = FoldShiftByConstant(Op0, CUI, I))
- return Res;
- return 0;
-}
-
-Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
- BinaryOperator &I) {
- bool isLeftShift = I.getOpcode() == Instruction::Shl;
-
- // See if we can simplify any instructions used by the instruction whose sole
- // purpose is to compute bits we don't care about.
- uint32_t TypeBits = Op0->getType()->getScalarSizeInBits();
-
- // shl i32 X, 32 = 0 and srl i8 Y, 9 = 0, ... just don't eliminate
- // a signed shift.
- //
- if (Op1->uge(TypeBits)) {
- if (I.getOpcode() != Instruction::AShr)
- return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
- else {
- I.setOperand(1, ConstantInt::get(I.getType(), TypeBits-1));
- return &I;
- }
- }
-
- // ((X*C1) << C2) == (X * (C1 << C2))
- if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0))
- if (BO->getOpcode() == Instruction::Mul && isLeftShift)
- if (Constant *BOOp = dyn_cast<Constant>(BO->getOperand(1)))
- return BinaryOperator::CreateMul(BO->getOperand(0),
- ConstantExpr::getShl(BOOp, Op1));
-
- // Try to fold constant and into select arguments.
- if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
- if (isa<PHINode>(Op0))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
-
- // Fold shift2(trunc(shift1(x,c1)), c2) -> trunc(shift2(shift1(x,c1),c2))
- if (TruncInst *TI = dyn_cast<TruncInst>(Op0)) {
- Instruction *TrOp = dyn_cast<Instruction>(TI->getOperand(0));
- // If 'shift2' is an ashr, we would have to get the sign bit into a funny
- // place. Don't try to do this transformation in this case. Also, we
- // require that the input operand is a shift-by-constant so that we have
- // confidence that the shifts will get folded together. We could do this
- // xform in more cases, but it is unlikely to be profitable.
- if (TrOp && I.isLogicalShift() && TrOp->isShift() &&
- isa<ConstantInt>(TrOp->getOperand(1))) {
- // Okay, we'll do this xform. Make the shift of shift.
- Constant *ShAmt = ConstantExpr::getZExt(Op1, TrOp->getType());
- // (shift2 (shift1 & 0x00FF), c2)
- Value *NSh = Builder->CreateBinOp(I.getOpcode(), TrOp, ShAmt,I.getName());
-
- // For logical shifts, the truncation has the effect of making the high
- // part of the register be zeros. Emulate this by inserting an AND to
- // clear the top bits as needed. This 'and' will usually be zapped by
- // other xforms later if dead.
- unsigned SrcSize = TrOp->getType()->getScalarSizeInBits();
- unsigned DstSize = TI->getType()->getScalarSizeInBits();
- APInt MaskV(APInt::getLowBitsSet(SrcSize, DstSize));
-
- // The mask we constructed says what the trunc would do if occurring
- // between the shifts. We want to know the effect *after* the second
- // shift. We know that it is a logical shift by a constant, so adjust the
- // mask as appropriate.
- if (I.getOpcode() == Instruction::Shl)
- MaskV <<= Op1->getZExtValue();
- else {
- assert(I.getOpcode() == Instruction::LShr && "Unknown logical shift");
- MaskV = MaskV.lshr(Op1->getZExtValue());
- }
-
- // shift1 & 0x00FF
- Value *And = Builder->CreateAnd(NSh,
- ConstantInt::get(I.getContext(), MaskV),
- TI->getName());
-
- // Return the value truncated to the interesting size.
- return new TruncInst(And, I.getType());
- }
- }
-
- if (Op0->hasOneUse()) {
- if (BinaryOperator *Op0BO = dyn_cast<BinaryOperator>(Op0)) {
- // Turn ((X >> C) + Y) << C -> (X + (Y << C)) & (~0 << C)
- Value *V1, *V2;
- ConstantInt *CC;
- switch (Op0BO->getOpcode()) {
- default: break;
- case Instruction::Add:
- case Instruction::And:
- case Instruction::Or:
- case Instruction::Xor: {
- // These operators commute.
- // Turn (Y + (X >> C)) << C -> (X + (Y << C)) & (~0 << C)
- if (isLeftShift && Op0BO->getOperand(1)->hasOneUse() &&
- match(Op0BO->getOperand(1), m_Shr(m_Value(V1),
- m_Specific(Op1)))) {
- Value *YS = // (Y << C)
- Builder->CreateShl(Op0BO->getOperand(0), Op1, Op0BO->getName());
- // (X + (Y << C))
- Value *X = Builder->CreateBinOp(Op0BO->getOpcode(), YS, V1,
- Op0BO->getOperand(1)->getName());
- uint32_t Op1Val = Op1->getLimitedValue(TypeBits);
- return BinaryOperator::CreateAnd(X, ConstantInt::get(I.getContext(),
- APInt::getHighBitsSet(TypeBits, TypeBits-Op1Val)));
- }
-
- // Turn (Y + ((X >> C) & CC)) << C -> ((X & (CC << C)) + (Y << C))
- Value *Op0BOOp1 = Op0BO->getOperand(1);
- if (isLeftShift && Op0BOOp1->hasOneUse() &&
- match(Op0BOOp1,
- m_And(m_Shr(m_Value(V1), m_Specific(Op1)),
- m_ConstantInt(CC))) &&
- cast<BinaryOperator>(Op0BOOp1)->getOperand(0)->hasOneUse()) {
- Value *YS = // (Y << C)
- Builder->CreateShl(Op0BO->getOperand(0), Op1,
- Op0BO->getName());
- // X & (CC << C)
- Value *XM = Builder->CreateAnd(V1, ConstantExpr::getShl(CC, Op1),
- V1->getName()+".mask");
- return BinaryOperator::Create(Op0BO->getOpcode(), YS, XM);
- }
- }
-
- // FALL THROUGH.
- case Instruction::Sub: {
- // Turn ((X >> C) + Y) << C -> (X + (Y << C)) & (~0 << C)
- if (isLeftShift && Op0BO->getOperand(0)->hasOneUse() &&
- match(Op0BO->getOperand(0), m_Shr(m_Value(V1),
- m_Specific(Op1)))) {
- Value *YS = // (Y << C)
- Builder->CreateShl(Op0BO->getOperand(1), Op1, Op0BO->getName());
- // (X + (Y << C))
- Value *X = Builder->CreateBinOp(Op0BO->getOpcode(), V1, YS,
- Op0BO->getOperand(0)->getName());
- uint32_t Op1Val = Op1->getLimitedValue(TypeBits);
- return BinaryOperator::CreateAnd(X, ConstantInt::get(I.getContext(),
- APInt::getHighBitsSet(TypeBits, TypeBits-Op1Val)));
- }
-
- // Turn (((X >> C)&CC) + Y) << C -> (X + (Y << C)) & (CC << C)
- if (isLeftShift && Op0BO->getOperand(0)->hasOneUse() &&
- match(Op0BO->getOperand(0),
- m_And(m_Shr(m_Value(V1), m_Value(V2)),
- m_ConstantInt(CC))) && V2 == Op1 &&
- cast<BinaryOperator>(Op0BO->getOperand(0))
- ->getOperand(0)->hasOneUse()) {
- Value *YS = // (Y << C)
- Builder->CreateShl(Op0BO->getOperand(1), Op1, Op0BO->getName());
- // X & (CC << C)
- Value *XM = Builder->CreateAnd(V1, ConstantExpr::getShl(CC, Op1),
- V1->getName()+".mask");
-
- return BinaryOperator::Create(Op0BO->getOpcode(), XM, YS);
- }
-
- break;
- }
- }
-
-
- // If the operand is an bitwise operator with a constant RHS, and the
- // shift is the only use, we can pull it out of the shift.
- if (ConstantInt *Op0C = dyn_cast<ConstantInt>(Op0BO->getOperand(1))) {
- bool isValid = true; // Valid only for And, Or, Xor
- bool highBitSet = false; // Transform if high bit of constant set?
-
- switch (Op0BO->getOpcode()) {
- default: isValid = false; break; // Do not perform transform!
- case Instruction::Add:
- isValid = isLeftShift;
- break;
- case Instruction::Or:
- case Instruction::Xor:
- highBitSet = false;
- break;
- case Instruction::And:
- highBitSet = true;
- break;
- }
-
- // If this is a signed shift right, and the high bit is modified
- // by the logical operation, do not perform the transformation.
- // The highBitSet boolean indicates the value of the high bit of
- // the constant which would cause it to be modified for this
- // operation.
- //
- if (isValid && I.getOpcode() == Instruction::AShr)
- isValid = Op0C->getValue()[TypeBits-1] == highBitSet;
-
- if (isValid) {
- Constant *NewRHS = ConstantExpr::get(I.getOpcode(), Op0C, Op1);
-
- Value *NewShift =
- Builder->CreateBinOp(I.getOpcode(), Op0BO->getOperand(0), Op1);
- NewShift->takeName(Op0BO);
-
- return BinaryOperator::Create(Op0BO->getOpcode(), NewShift,
- NewRHS);
- }
- }
- }
- }
-
- // Find out if this is a shift of a shift by a constant.
- BinaryOperator *ShiftOp = dyn_cast<BinaryOperator>(Op0);
- if (ShiftOp && !ShiftOp->isShift())
- ShiftOp = 0;
-
- if (ShiftOp && isa<ConstantInt>(ShiftOp->getOperand(1))) {
- ConstantInt *ShiftAmt1C = cast<ConstantInt>(ShiftOp->getOperand(1));
- uint32_t ShiftAmt1 = ShiftAmt1C->getLimitedValue(TypeBits);
- uint32_t ShiftAmt2 = Op1->getLimitedValue(TypeBits);
- assert(ShiftAmt2 != 0 && "Should have been simplified earlier");
- if (ShiftAmt1 == 0) return 0; // Will be simplified in the future.
- Value *X = ShiftOp->getOperand(0);
-
- uint32_t AmtSum = ShiftAmt1+ShiftAmt2; // Fold into one big shift.
-
- const IntegerType *Ty = cast<IntegerType>(I.getType());
-
- // Check for (X << c1) << c2 and (X >> c1) >> c2
- if (I.getOpcode() == ShiftOp->getOpcode()) {
- // If this is oversized composite shift, then unsigned shifts get 0, ashr
- // saturates.
- if (AmtSum >= TypeBits) {
- if (I.getOpcode() != Instruction::AShr)
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- AmtSum = TypeBits-1; // Saturate to 31 for i32 ashr.
- }
-
- return BinaryOperator::Create(I.getOpcode(), X,
- ConstantInt::get(Ty, AmtSum));
- }
-
- if (ShiftOp->getOpcode() == Instruction::LShr &&
- I.getOpcode() == Instruction::AShr) {
- if (AmtSum >= TypeBits)
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
- // ((X >>u C1) >>s C2) -> (X >>u (C1+C2)) since C1 != 0.
- return BinaryOperator::CreateLShr(X, ConstantInt::get(Ty, AmtSum));
- }
-
- if (ShiftOp->getOpcode() == Instruction::AShr &&
- I.getOpcode() == Instruction::LShr) {
- // ((X >>s C1) >>u C2) -> ((X >>s (C1+C2)) & mask) since C1 != 0.
- if (AmtSum >= TypeBits)
- AmtSum = TypeBits-1;
-
- Value *Shift = Builder->CreateAShr(X, ConstantInt::get(Ty, AmtSum));
-
- APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt2));
- return BinaryOperator::CreateAnd(Shift,
- ConstantInt::get(I.getContext(), Mask));
- }
-
- // Okay, if we get here, one shift must be left, and the other shift must be
- // right. See if the amounts are equal.
- if (ShiftAmt1 == ShiftAmt2) {
- // If we have ((X >>? C) << C), turn this into X & (-1 << C).
- if (I.getOpcode() == Instruction::Shl) {
- APInt Mask(APInt::getHighBitsSet(TypeBits, TypeBits - ShiftAmt1));
- return BinaryOperator::CreateAnd(X,
- ConstantInt::get(I.getContext(),Mask));
- }
- // If we have ((X << C) >>u C), turn this into X & (-1 >>u C).
- if (I.getOpcode() == Instruction::LShr) {
- APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt1));
- return BinaryOperator::CreateAnd(X,
- ConstantInt::get(I.getContext(), Mask));
- }
- // We can simplify ((X << C) >>s C) into a trunc + sext.
- // NOTE: we could do this for any C, but that would make 'unusual' integer
- // types. For now, just stick to ones well-supported by the code
- // generators.
- const Type *SExtType = 0;
- switch (Ty->getBitWidth() - ShiftAmt1) {
- case 1 :
- case 8 :
- case 16 :
- case 32 :
- case 64 :
- case 128:
- SExtType = IntegerType::get(I.getContext(),
- Ty->getBitWidth() - ShiftAmt1);
- break;
- default: break;
- }
- if (SExtType)
- return new SExtInst(Builder->CreateTrunc(X, SExtType, "sext"), Ty);
- // Otherwise, we can't handle it yet.
- } else if (ShiftAmt1 < ShiftAmt2) {
- uint32_t ShiftDiff = ShiftAmt2-ShiftAmt1;
-
- // (X >>? C1) << C2 --> X << (C2-C1) & (-1 << C2)
- if (I.getOpcode() == Instruction::Shl) {
- assert(ShiftOp->getOpcode() == Instruction::LShr ||
- ShiftOp->getOpcode() == Instruction::AShr);
- Value *Shift = Builder->CreateShl(X, ConstantInt::get(Ty, ShiftDiff));
-
- APInt Mask(APInt::getHighBitsSet(TypeBits, TypeBits - ShiftAmt2));
- return BinaryOperator::CreateAnd(Shift,
- ConstantInt::get(I.getContext(),Mask));
- }
-
- // (X << C1) >>u C2 --> X >>u (C2-C1) & (-1 >> C2)
- if (I.getOpcode() == Instruction::LShr) {
- assert(ShiftOp->getOpcode() == Instruction::Shl);
- Value *Shift = Builder->CreateLShr(X, ConstantInt::get(Ty, ShiftDiff));
-
- APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt2));
- return BinaryOperator::CreateAnd(Shift,
- ConstantInt::get(I.getContext(),Mask));
- }
-
- // We can't handle (X << C1) >>s C2, it shifts arbitrary bits in.
- } else {
- assert(ShiftAmt2 < ShiftAmt1);
- uint32_t ShiftDiff = ShiftAmt1-ShiftAmt2;
-
- // (X >>? C1) << C2 --> X >>? (C1-C2) & (-1 << C2)
- if (I.getOpcode() == Instruction::Shl) {
- assert(ShiftOp->getOpcode() == Instruction::LShr ||
- ShiftOp->getOpcode() == Instruction::AShr);
- Value *Shift = Builder->CreateBinOp(ShiftOp->getOpcode(), X,
- ConstantInt::get(Ty, ShiftDiff));
-
- APInt Mask(APInt::getHighBitsSet(TypeBits, TypeBits - ShiftAmt2));
- return BinaryOperator::CreateAnd(Shift,
- ConstantInt::get(I.getContext(),Mask));
- }
-
- // (X << C1) >>u C2 --> X << (C1-C2) & (-1 >> C2)
- if (I.getOpcode() == Instruction::LShr) {
- assert(ShiftOp->getOpcode() == Instruction::Shl);
- Value *Shift = Builder->CreateShl(X, ConstantInt::get(Ty, ShiftDiff));
-
- APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt2));
- return BinaryOperator::CreateAnd(Shift,
- ConstantInt::get(I.getContext(),Mask));
- }
-
- // We can't handle (X << C1) >>a C2, it shifts arbitrary bits in.
- }
- }
- return 0;
-}
-
-
-/// DecomposeSimpleLinearExpr - Analyze 'Val', seeing if it is a simple linear
-/// expression. If so, decompose it, returning some value X, such that Val is
-/// X*Scale+Offset.
-///
-static Value *DecomposeSimpleLinearExpr(Value *Val, unsigned &Scale,
- int &Offset) {
- assert(Val->getType() == Type::getInt32Ty(Val->getContext()) &&
- "Unexpected allocation size type!");
- if (ConstantInt *CI = dyn_cast<ConstantInt>(Val)) {
- Offset = CI->getZExtValue();
- Scale = 0;
- return ConstantInt::get(Type::getInt32Ty(Val->getContext()), 0);
- } else if (BinaryOperator *I = dyn_cast<BinaryOperator>(Val)) {
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(I->getOperand(1))) {
- if (I->getOpcode() == Instruction::Shl) {
- // This is a value scaled by '1 << the shift amt'.
- Scale = 1U << RHS->getZExtValue();
- Offset = 0;
- return I->getOperand(0);
- } else if (I->getOpcode() == Instruction::Mul) {
- // This value is scaled by 'RHS'.
- Scale = RHS->getZExtValue();
- Offset = 0;
- return I->getOperand(0);
- } else if (I->getOpcode() == Instruction::Add) {
- // We have X+C. Check to see if we really have (X*C2)+C1,
- // where C1 is divisible by C2.
- unsigned SubScale;
- Value *SubVal =
- DecomposeSimpleLinearExpr(I->getOperand(0), SubScale, Offset);
- Offset += RHS->getZExtValue();
- Scale = SubScale;
- return SubVal;
- }
- }
- }
-
- // Otherwise, we can't look past this.
- Scale = 1;
- Offset = 0;
- return Val;
-}
-
-
-/// PromoteCastOfAllocation - If we find a cast of an allocation instruction,
-/// try to eliminate the cast by moving the type information into the alloc.
-Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI,
- AllocaInst &AI) {
- const PointerType *PTy = cast<PointerType>(CI.getType());
-
- BuilderTy AllocaBuilder(*Builder);
- AllocaBuilder.SetInsertPoint(AI.getParent(), &AI);
-
- // Remove any uses of AI that are dead.
- assert(!CI.use_empty() && "Dead instructions should be removed earlier!");
-
- for (Value::use_iterator UI = AI.use_begin(), E = AI.use_end(); UI != E; ) {
- Instruction *User = cast<Instruction>(*UI++);
- if (isInstructionTriviallyDead(User)) {
- while (UI != E && *UI == User)
- ++UI; // If this instruction uses AI more than once, don't break UI.
-
- ++NumDeadInst;
- DEBUG(errs() << "IC: DCE: " << *User << '\n');
- EraseInstFromFunction(*User);
- }
- }
-
- // This requires TargetData to get the alloca alignment and size information.
- if (!TD) return 0;
-
- // Get the type really allocated and the type casted to.
- const Type *AllocElTy = AI.getAllocatedType();
- const Type *CastElTy = PTy->getElementType();
- if (!AllocElTy->isSized() || !CastElTy->isSized()) return 0;
-
- unsigned AllocElTyAlign = TD->getABITypeAlignment(AllocElTy);
- unsigned CastElTyAlign = TD->getABITypeAlignment(CastElTy);
- if (CastElTyAlign < AllocElTyAlign) return 0;
-
- // If the allocation has multiple uses, only promote it if we are strictly
- // increasing the alignment of the resultant allocation. If we keep it the
- // same, we open the door to infinite loops of various kinds. (A reference
- // from a dbg.declare doesn't count as a use for this purpose.)
- if (!AI.hasOneUse() && !hasOneUsePlusDeclare(&AI) &&
- CastElTyAlign == AllocElTyAlign) return 0;
-
- uint64_t AllocElTySize = TD->getTypeAllocSize(AllocElTy);
- uint64_t CastElTySize = TD->getTypeAllocSize(CastElTy);
- if (CastElTySize == 0 || AllocElTySize == 0) return 0;
-
- // See if we can satisfy the modulus by pulling a scale out of the array
- // size argument.
- unsigned ArraySizeScale;
- int ArrayOffset;
- Value *NumElements = // See if the array size is a decomposable linear expr.
- DecomposeSimpleLinearExpr(AI.getOperand(0), ArraySizeScale, ArrayOffset);
-
- // If we can now satisfy the modulus, by using a non-1 scale, we really can
- // do the xform.
- if ((AllocElTySize*ArraySizeScale) % CastElTySize != 0 ||
- (AllocElTySize*ArrayOffset ) % CastElTySize != 0) return 0;
-
- unsigned Scale = (AllocElTySize*ArraySizeScale)/CastElTySize;
- Value *Amt = 0;
- if (Scale == 1) {
- Amt = NumElements;
- } else {
- Amt = ConstantInt::get(Type::getInt32Ty(CI.getContext()), Scale);
- // Insert before the alloca, not before the cast.
- Amt = AllocaBuilder.CreateMul(Amt, NumElements, "tmp");
- }
-
- if (int Offset = (AllocElTySize*ArrayOffset)/CastElTySize) {
- Value *Off = ConstantInt::get(Type::getInt32Ty(CI.getContext()),
- Offset, true);
- Amt = AllocaBuilder.CreateAdd(Amt, Off, "tmp");
- }
-
- AllocaInst *New = AllocaBuilder.CreateAlloca(CastElTy, Amt);
- New->setAlignment(AI.getAlignment());
- New->takeName(&AI);
-
- // If the allocation has one real use plus a dbg.declare, just remove the
- // declare.
- if (DbgDeclareInst *DI = hasOneUsePlusDeclare(&AI)) {
- EraseInstFromFunction(*DI);
- }
- // If the allocation has multiple real uses, insert a cast and change all
- // things that used it to use the new cast. This will also hack on CI, but it
- // will die soon.
- else if (!AI.hasOneUse()) {
- // New is the allocation instruction, pointer typed. AI is the original
- // allocation instruction, also pointer typed. Thus, cast to use is BitCast.
- Value *NewCast = AllocaBuilder.CreateBitCast(New, AI.getType(), "tmpcast");
- AI.replaceAllUsesWith(NewCast);
- }
- return ReplaceInstUsesWith(CI, New);
-}
-
-
-/// FindElementAtOffset - Given a type and a constant offset, determine whether
-/// or not there is a sequence of GEP indices into the type that will land us at
-/// the specified offset. If so, fill them into NewIndices and return the
-/// resultant element type, otherwise return null.
-const Type *InstCombiner::FindElementAtOffset(const Type *Ty, int64_t Offset,
- SmallVectorImpl<Value*> &NewIndices) {
- if (!TD) return 0;
- if (!Ty->isSized()) return 0;
-
- // Start with the index over the outer type. Note that the type size
- // might be zero (even if the offset isn't zero) if the indexed type
- // is something like [0 x {int, int}]
- const Type *IntPtrTy = TD->getIntPtrType(Ty->getContext());
- int64_t FirstIdx = 0;
- if (int64_t TySize = TD->getTypeAllocSize(Ty)) {
- FirstIdx = Offset/TySize;
- Offset -= FirstIdx*TySize;
-
- // Handle hosts where % returns negative instead of values [0..TySize).
- if (Offset < 0) {
- --FirstIdx;
- Offset += TySize;
- assert(Offset >= 0);
- }
- assert((uint64_t)Offset < (uint64_t)TySize && "Out of range offset");
- }
-
- NewIndices.push_back(ConstantInt::get(IntPtrTy, FirstIdx));
-
- // Index into the types. If we fail, set OrigBase to null.
- while (Offset) {
- // Indexing into tail padding between struct/array elements.
- if (uint64_t(Offset*8) >= TD->getTypeSizeInBits(Ty))
- return 0;
-
- if (const StructType *STy = dyn_cast<StructType>(Ty)) {
- const StructLayout *SL = TD->getStructLayout(STy);
- assert(Offset < (int64_t)SL->getSizeInBytes() &&
- "Offset must stay within the indexed type");
-
- unsigned Elt = SL->getElementContainingOffset(Offset);
- NewIndices.push_back(ConstantInt::get(Type::getInt32Ty(Ty->getContext()),
- Elt));
-
- Offset -= SL->getElementOffset(Elt);
- Ty = STy->getElementType(Elt);
- } else if (const ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
- uint64_t EltSize = TD->getTypeAllocSize(AT->getElementType());
- assert(EltSize && "Cannot index into a zero-sized array");
- NewIndices.push_back(ConstantInt::get(IntPtrTy,Offset/EltSize));
- Offset %= EltSize;
- Ty = AT->getElementType();
- } else {
- // Otherwise, we can't index into the middle of this atomic type, bail.
- return 0;
- }
- }
-
- return Ty;
-}
-
-
-/// GetSelectFoldableOperands - We want to turn code that looks like this:
-/// %C = or %A, %B
-/// %D = select %cond, %C, %A
-/// into:
-/// %C = select %cond, %B, 0
-/// %D = or %A, %C
-///
-/// Assuming that the specified instruction is an operand to the select, return
-/// a bitmask indicating which operands of this instruction are foldable if they
-/// equal the other incoming value of the select.
-///
-static unsigned GetSelectFoldableOperands(Instruction *I) {
- switch (I->getOpcode()) {
- case Instruction::Add:
- case Instruction::Mul:
- case Instruction::And:
- case Instruction::Or:
- case Instruction::Xor:
- return 3; // Can fold through either operand.
- case Instruction::Sub: // Can only fold on the amount subtracted.
- case Instruction::Shl: // Can only fold on the shift amount.
- case Instruction::LShr:
- case Instruction::AShr:
- return 1;
- default:
- return 0; // Cannot fold
- }
-}
-
-/// GetSelectFoldableConstant - For the same transformation as the previous
-/// function, return the identity constant that goes into the select.
-static Constant *GetSelectFoldableConstant(Instruction *I) {
- switch (I->getOpcode()) {
- default: llvm_unreachable("This cannot happen!");
- case Instruction::Add:
- case Instruction::Sub:
- case Instruction::Or:
- case Instruction::Xor:
- case Instruction::Shl:
- case Instruction::LShr:
- case Instruction::AShr:
- return Constant::getNullValue(I->getType());
- case Instruction::And:
- return Constant::getAllOnesValue(I->getType());
- case Instruction::Mul:
- return ConstantInt::get(I->getType(), 1);
- }
-}
-
-/// FoldSelectOpOp - Here we have (select c, TI, FI), and we know that TI and FI
-/// have the same opcode and only one use each. Try to simplify this.
-Instruction *InstCombiner::FoldSelectOpOp(SelectInst &SI, Instruction *TI,
- Instruction *FI) {
- if (TI->getNumOperands() == 1) {
- // If this is a non-volatile load or a cast from the same type,
- // merge.
- if (TI->isCast()) {
- if (TI->getOperand(0)->getType() != FI->getOperand(0)->getType())
- return 0;
- } else {
- return 0; // unknown unary op.
- }
-
- // Fold this by inserting a select from the input values.
- SelectInst *NewSI = SelectInst::Create(SI.getCondition(), TI->getOperand(0),
- FI->getOperand(0), SI.getName()+".v");
- InsertNewInstBefore(NewSI, SI);
- return CastInst::Create(Instruction::CastOps(TI->getOpcode()), NewSI,
- TI->getType());
- }
-
- // Only handle binary operators here.
- if (!isa<BinaryOperator>(TI))
- return 0;
-
- // Figure out if the operations have any operands in common.
- Value *MatchOp, *OtherOpT, *OtherOpF;
- bool MatchIsOpZero;
- if (TI->getOperand(0) == FI->getOperand(0)) {
- MatchOp = TI->getOperand(0);
- OtherOpT = TI->getOperand(1);
- OtherOpF = FI->getOperand(1);
- MatchIsOpZero = true;
- } else if (TI->getOperand(1) == FI->getOperand(1)) {
- MatchOp = TI->getOperand(1);
- OtherOpT = TI->getOperand(0);
- OtherOpF = FI->getOperand(0);
- MatchIsOpZero = false;
- } else if (!TI->isCommutative()) {
- return 0;
- } else if (TI->getOperand(0) == FI->getOperand(1)) {
- MatchOp = TI->getOperand(0);
- OtherOpT = TI->getOperand(1);
- OtherOpF = FI->getOperand(0);
- MatchIsOpZero = true;
- } else if (TI->getOperand(1) == FI->getOperand(0)) {
- MatchOp = TI->getOperand(1);
- OtherOpT = TI->getOperand(0);
- OtherOpF = FI->getOperand(1);
- MatchIsOpZero = true;
- } else {
- return 0;
- }
-
- // If we reach here, they do have operations in common.
- SelectInst *NewSI = SelectInst::Create(SI.getCondition(), OtherOpT,
- OtherOpF, SI.getName()+".v");
- InsertNewInstBefore(NewSI, SI);
-
- if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TI)) {
- if (MatchIsOpZero)
- return BinaryOperator::Create(BO->getOpcode(), MatchOp, NewSI);
- else
- return BinaryOperator::Create(BO->getOpcode(), NewSI, MatchOp);
- }
- llvm_unreachable("Shouldn't get here");
- return 0;
-}
-
-static bool isSelect01(Constant *C1, Constant *C2) {
- ConstantInt *C1I = dyn_cast<ConstantInt>(C1);
- if (!C1I)
- return false;
- ConstantInt *C2I = dyn_cast<ConstantInt>(C2);
- if (!C2I)
- return false;
- return (C1I->isZero() || C1I->isOne()) && (C2I->isZero() || C2I->isOne());
-}
-
-/// FoldSelectIntoOp - Try fold the select into one of the operands to
-/// facilitate further optimization.
-Instruction *InstCombiner::FoldSelectIntoOp(SelectInst &SI, Value *TrueVal,
- Value *FalseVal) {
- // See the comment above GetSelectFoldableOperands for a description of the
- // transformation we are doing here.
- if (Instruction *TVI = dyn_cast<Instruction>(TrueVal)) {
- if (TVI->hasOneUse() && TVI->getNumOperands() == 2 &&
- !isa<Constant>(FalseVal)) {
- if (unsigned SFO = GetSelectFoldableOperands(TVI)) {
- unsigned OpToFold = 0;
- if ((SFO & 1) && FalseVal == TVI->getOperand(0)) {
- OpToFold = 1;
- } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) {
- OpToFold = 2;
- }
-
- if (OpToFold) {
- Constant *C = GetSelectFoldableConstant(TVI);
- Value *OOp = TVI->getOperand(2-OpToFold);
- // Avoid creating select between 2 constants unless it's selecting
- // between 0 and 1.
- if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) {
- Instruction *NewSel = SelectInst::Create(SI.getCondition(), OOp, C);
- InsertNewInstBefore(NewSel, SI);
- NewSel->takeName(TVI);
- if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TVI))
- return BinaryOperator::Create(BO->getOpcode(), FalseVal, NewSel);
- llvm_unreachable("Unknown instruction!!");
- }
- }
- }
- }
- }
-
- if (Instruction *FVI = dyn_cast<Instruction>(FalseVal)) {
- if (FVI->hasOneUse() && FVI->getNumOperands() == 2 &&
- !isa<Constant>(TrueVal)) {
- if (unsigned SFO = GetSelectFoldableOperands(FVI)) {
- unsigned OpToFold = 0;
- if ((SFO & 1) && TrueVal == FVI->getOperand(0)) {
- OpToFold = 1;
- } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) {
- OpToFold = 2;
- }
-
- if (OpToFold) {
- Constant *C = GetSelectFoldableConstant(FVI);
- Value *OOp = FVI->getOperand(2-OpToFold);
- // Avoid creating select between 2 constants unless it's selecting
- // between 0 and 1.
- if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) {
- Instruction *NewSel = SelectInst::Create(SI.getCondition(), C, OOp);
- InsertNewInstBefore(NewSel, SI);
- NewSel->takeName(FVI);
- if (BinaryOperator *BO = dyn_cast<BinaryOperator>(FVI))
- return BinaryOperator::Create(BO->getOpcode(), TrueVal, NewSel);
- llvm_unreachable("Unknown instruction!!");
- }
- }
- }
- }
- }
-
- return 0;
-}
-
-/// visitSelectInstWithICmp - Visit a SelectInst that has an
-/// ICmpInst as its first operand.
-///
-Instruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI,
- ICmpInst *ICI) {
- bool Changed = false;
- ICmpInst::Predicate Pred = ICI->getPredicate();
- Value *CmpLHS = ICI->getOperand(0);
- Value *CmpRHS = ICI->getOperand(1);
- Value *TrueVal = SI.getTrueValue();
- Value *FalseVal = SI.getFalseValue();
-
- // Check cases where the comparison is with a constant that
- // can be adjusted to fit the min/max idiom. We may edit ICI in
- // place here, so make sure the select is the only user.
- if (ICI->hasOneUse())
- if (ConstantInt *CI = dyn_cast<ConstantInt>(CmpRHS)) {
- switch (Pred) {
- default: break;
- case ICmpInst::ICMP_ULT:
- case ICmpInst::ICMP_SLT: {
- // X < MIN ? T : F --> F
- if (CI->isMinValue(Pred == ICmpInst::ICMP_SLT))
- return ReplaceInstUsesWith(SI, FalseVal);
- // X < C ? X : C-1 --> X > C-1 ? C-1 : X
- Constant *AdjustedRHS = SubOne(CI);
- if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) ||
- (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) {
- Pred = ICmpInst::getSwappedPredicate(Pred);
- CmpRHS = AdjustedRHS;
- std::swap(FalseVal, TrueVal);
- ICI->setPredicate(Pred);
- ICI->setOperand(1, CmpRHS);
- SI.setOperand(1, TrueVal);
- SI.setOperand(2, FalseVal);
- Changed = true;
- }
- break;
- }
- case ICmpInst::ICMP_UGT:
- case ICmpInst::ICMP_SGT: {
- // X > MAX ? T : F --> F
- if (CI->isMaxValue(Pred == ICmpInst::ICMP_SGT))
- return ReplaceInstUsesWith(SI, FalseVal);
- // X > C ? X : C+1 --> X < C+1 ? C+1 : X
- Constant *AdjustedRHS = AddOne(CI);
- if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) ||
- (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) {
- Pred = ICmpInst::getSwappedPredicate(Pred);
- CmpRHS = AdjustedRHS;
- std::swap(FalseVal, TrueVal);
- ICI->setPredicate(Pred);
- ICI->setOperand(1, CmpRHS);
- SI.setOperand(1, TrueVal);
- SI.setOperand(2, FalseVal);
- Changed = true;
- }
- break;
- }
- }
-
- // (x <s 0) ? -1 : 0 -> ashr x, 31 -> all ones if signed
- // (x >s -1) ? -1 : 0 -> ashr x, 31 -> all ones if not signed
- CmpInst::Predicate Pred = CmpInst::BAD_ICMP_PREDICATE;
- if (match(TrueVal, m_ConstantInt<-1>()) &&
- match(FalseVal, m_ConstantInt<0>()))
- Pred = ICI->getPredicate();
- else if (match(TrueVal, m_ConstantInt<0>()) &&
- match(FalseVal, m_ConstantInt<-1>()))
- Pred = CmpInst::getInversePredicate(ICI->getPredicate());
-
- if (Pred != CmpInst::BAD_ICMP_PREDICATE) {
- // If we are just checking for a icmp eq of a single bit and zext'ing it
- // to an integer, then shift the bit to the appropriate place and then
- // cast to integer to avoid the comparison.
- const APInt &Op1CV = CI->getValue();
-
- // sext (x <s 0) to i32 --> x>>s31 true if signbit set.
- // sext (x >s -1) to i32 --> (x>>s31)^-1 true if signbit clear.
- if ((Pred == ICmpInst::ICMP_SLT && Op1CV == 0) ||
- (Pred == ICmpInst::ICMP_SGT && Op1CV.isAllOnesValue())) {
- Value *In = ICI->getOperand(0);
- Value *Sh = ConstantInt::get(In->getType(),
- In->getType()->getScalarSizeInBits()-1);
- In = InsertNewInstBefore(BinaryOperator::CreateAShr(In, Sh,
- In->getName()+".lobit"),
- *ICI);
- if (In->getType() != SI.getType())
- In = CastInst::CreateIntegerCast(In, SI.getType(),
- true/*SExt*/, "tmp", ICI);
-
- if (Pred == ICmpInst::ICMP_SGT)
- In = InsertNewInstBefore(BinaryOperator::CreateNot(In,
- In->getName()+".not"), *ICI);
-
- return ReplaceInstUsesWith(SI, In);
- }
- }
- }
-
- if (CmpLHS == TrueVal && CmpRHS == FalseVal) {
- // Transform (X == Y) ? X : Y -> Y
- if (Pred == ICmpInst::ICMP_EQ)
- return ReplaceInstUsesWith(SI, FalseVal);
- // Transform (X != Y) ? X : Y -> X
- if (Pred == ICmpInst::ICMP_NE)
- return ReplaceInstUsesWith(SI, TrueVal);
- /// NOTE: if we wanted to, this is where to detect integer MIN/MAX
-
- } else if (CmpLHS == FalseVal && CmpRHS == TrueVal) {
- // Transform (X == Y) ? Y : X -> X
- if (Pred == ICmpInst::ICMP_EQ)
- return ReplaceInstUsesWith(SI, FalseVal);
- // Transform (X != Y) ? Y : X -> Y
- if (Pred == ICmpInst::ICMP_NE)
- return ReplaceInstUsesWith(SI, TrueVal);
- /// NOTE: if we wanted to, this is where to detect integer MIN/MAX
- }
- return Changed ? &SI : 0;
-}
-
-
-/// CanSelectOperandBeMappingIntoPredBlock - SI is a select whose condition is a
-/// PHI node (but the two may be in different blocks). See if the true/false
-/// values (V) are live in all of the predecessor blocks of the PHI. For
-/// example, cases like this cannot be mapped:
-///
-/// X = phi [ C1, BB1], [C2, BB2]
-/// Y = add
-/// Z = select X, Y, 0
-///
-/// because Y is not live in BB1/BB2.
-///
-static bool CanSelectOperandBeMappingIntoPredBlock(const Value *V,
- const SelectInst &SI) {
- // If the value is a non-instruction value like a constant or argument, it
- // can always be mapped.
- const Instruction *I = dyn_cast<Instruction>(V);
- if (I == 0) return true;
-
- // If V is a PHI node defined in the same block as the condition PHI, we can
- // map the arguments.
- const PHINode *CondPHI = cast<PHINode>(SI.getCondition());
-
- if (const PHINode *VP = dyn_cast<PHINode>(I))
- if (VP->getParent() == CondPHI->getParent())
- return true;
-
- // Otherwise, if the PHI and select are defined in the same block and if V is
- // defined in a different block, then we can transform it.
- if (SI.getParent() == CondPHI->getParent() &&
- I->getParent() != CondPHI->getParent())
- return true;
-
- // Otherwise we have a 'hard' case and we can't tell without doing more
- // detailed dominator based analysis, punt.
- return false;
-}
-
-/// FoldSPFofSPF - We have an SPF (e.g. a min or max) of an SPF of the form:
-/// SPF2(SPF1(A, B), C)
-Instruction *InstCombiner::FoldSPFofSPF(Instruction *Inner,
- SelectPatternFlavor SPF1,
- Value *A, Value *B,
- Instruction &Outer,
- SelectPatternFlavor SPF2, Value *C) {
- if (C == A || C == B) {
- // MAX(MAX(A, B), B) -> MAX(A, B)
- // MIN(MIN(a, b), a) -> MIN(a, b)
- if (SPF1 == SPF2)
- return ReplaceInstUsesWith(Outer, Inner);
-
- // MAX(MIN(a, b), a) -> a
- // MIN(MAX(a, b), a) -> a
- if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) ||
- (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) ||
- (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) ||
- (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN))
- return ReplaceInstUsesWith(Outer, C);
- }
-
- // TODO: MIN(MIN(A, 23), 97)
- return 0;
-}
-
-
-
-
-Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
- Value *CondVal = SI.getCondition();
- Value *TrueVal = SI.getTrueValue();
- Value *FalseVal = SI.getFalseValue();
-
- // select true, X, Y -> X
- // select false, X, Y -> Y
- if (ConstantInt *C = dyn_cast<ConstantInt>(CondVal))
- return ReplaceInstUsesWith(SI, C->getZExtValue() ? TrueVal : FalseVal);
-
- // select C, X, X -> X
- if (TrueVal == FalseVal)
- return ReplaceInstUsesWith(SI, TrueVal);
-
- if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
- return ReplaceInstUsesWith(SI, FalseVal);
- if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
- return ReplaceInstUsesWith(SI, TrueVal);
- if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
- if (isa<Constant>(TrueVal))
- return ReplaceInstUsesWith(SI, TrueVal);
- else
- return ReplaceInstUsesWith(SI, FalseVal);
- }
-
- if (SI.getType() == Type::getInt1Ty(SI.getContext())) {
- if (ConstantInt *C = dyn_cast<ConstantInt>(TrueVal)) {
- if (C->getZExtValue()) {
- // Change: A = select B, true, C --> A = or B, C
- return BinaryOperator::CreateOr(CondVal, FalseVal);
- } else {
- // Change: A = select B, false, C --> A = and !B, C
- Value *NotCond =
- InsertNewInstBefore(BinaryOperator::CreateNot(CondVal,
- "not."+CondVal->getName()), SI);
- return BinaryOperator::CreateAnd(NotCond, FalseVal);
- }
- } else if (ConstantInt *C = dyn_cast<ConstantInt>(FalseVal)) {
- if (C->getZExtValue() == false) {
- // Change: A = select B, C, false --> A = and B, C
- return BinaryOperator::CreateAnd(CondVal, TrueVal);
- } else {
- // Change: A = select B, C, true --> A = or !B, C
- Value *NotCond =
- InsertNewInstBefore(BinaryOperator::CreateNot(CondVal,
- "not."+CondVal->getName()), SI);
- return BinaryOperator::CreateOr(NotCond, TrueVal);
- }
- }
-
- // select a, b, a -> a&b
- // select a, a, b -> a|b
- if (CondVal == TrueVal)
- return BinaryOperator::CreateOr(CondVal, FalseVal);
- else if (CondVal == FalseVal)
- return BinaryOperator::CreateAnd(CondVal, TrueVal);
- }
-
- // Selecting between two integer constants?
- if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal))
- if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal)) {
- // select C, 1, 0 -> zext C to int
- if (FalseValC->isZero() && TrueValC->getValue() == 1) {
- return CastInst::Create(Instruction::ZExt, CondVal, SI.getType());
- } else if (TrueValC->isZero() && FalseValC->getValue() == 1) {
- // select C, 0, 1 -> zext !C to int
- Value *NotCond =
- InsertNewInstBefore(BinaryOperator::CreateNot(CondVal,
- "not."+CondVal->getName()), SI);
- return CastInst::Create(Instruction::ZExt, NotCond, SI.getType());
- }
-
- if (ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition())) {
- // If one of the constants is zero (we know they can't both be) and we
- // have an icmp instruction with zero, and we have an 'and' with the
- // non-constant value, eliminate this whole mess. This corresponds to
- // cases like this: ((X & 27) ? 27 : 0)
- if (TrueValC->isZero() || FalseValC->isZero())
- if (IC->isEquality() && isa<ConstantInt>(IC->getOperand(1)) &&
- cast<Constant>(IC->getOperand(1))->isNullValue())
- if (Instruction *ICA = dyn_cast<Instruction>(IC->getOperand(0)))
- if (ICA->getOpcode() == Instruction::And &&
- isa<ConstantInt>(ICA->getOperand(1)) &&
- (ICA->getOperand(1) == TrueValC ||
- ICA->getOperand(1) == FalseValC) &&
- isOneBitSet(cast<ConstantInt>(ICA->getOperand(1)))) {
- // Okay, now we know that everything is set up, we just don't
- // know whether we have a icmp_ne or icmp_eq and whether the
- // true or false val is the zero.
- bool ShouldNotVal = !TrueValC->isZero();
- ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE;
- Value *V = ICA;
- if (ShouldNotVal)
- V = InsertNewInstBefore(BinaryOperator::Create(
- Instruction::Xor, V, ICA->getOperand(1)), SI);
- return ReplaceInstUsesWith(SI, V);
- }
- }
- }
-
- // See if we are selecting two values based on a comparison of the two values.
- if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) {
- if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) {
- // Transform (X == Y) ? X : Y -> Y
- if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
- // This is not safe in general for floating point:
- // consider X== -0, Y== +0.
- // It becomes safe if either operand is a nonzero constant.
- ConstantFP *CFPt, *CFPf;
- if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
- !CFPt->getValueAPF().isZero()) ||
- ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
- !CFPf->getValueAPF().isZero()))
- return ReplaceInstUsesWith(SI, FalseVal);
- }
- // Transform (X != Y) ? X : Y -> X
- if (FCI->getPredicate() == FCmpInst::FCMP_ONE)
- return ReplaceInstUsesWith(SI, TrueVal);
- // NOTE: if we wanted to, this is where to detect MIN/MAX
-
- } else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){
- // Transform (X == Y) ? Y : X -> X
- if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
- // This is not safe in general for floating point:
- // consider X== -0, Y== +0.
- // It becomes safe if either operand is a nonzero constant.
- ConstantFP *CFPt, *CFPf;
- if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
- !CFPt->getValueAPF().isZero()) ||
- ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
- !CFPf->getValueAPF().isZero()))
- return ReplaceInstUsesWith(SI, FalseVal);
- }
- // Transform (X != Y) ? Y : X -> Y
- if (FCI->getPredicate() == FCmpInst::FCMP_ONE)
- return ReplaceInstUsesWith(SI, TrueVal);
- // NOTE: if we wanted to, this is where to detect MIN/MAX
- }
- // NOTE: if we wanted to, this is where to detect ABS
- }
-
- // See if we are selecting two values based on a comparison of the two values.
- if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal))
- if (Instruction *Result = visitSelectInstWithICmp(SI, ICI))
- return Result;
-
- if (Instruction *TI = dyn_cast<Instruction>(TrueVal))
- if (Instruction *FI = dyn_cast<Instruction>(FalseVal))
- if (TI->hasOneUse() && FI->hasOneUse()) {
- Instruction *AddOp = 0, *SubOp = 0;
-
- // Turn (select C, (op X, Y), (op X, Z)) -> (op X, (select C, Y, Z))
- if (TI->getOpcode() == FI->getOpcode())
- if (Instruction *IV = FoldSelectOpOp(SI, TI, FI))
- return IV;
-
- // Turn select C, (X+Y), (X-Y) --> (X+(select C, Y, (-Y))). This is
- // even legal for FP.
- if ((TI->getOpcode() == Instruction::Sub &&
- FI->getOpcode() == Instruction::Add) ||
- (TI->getOpcode() == Instruction::FSub &&
- FI->getOpcode() == Instruction::FAdd)) {
- AddOp = FI; SubOp = TI;
- } else if ((FI->getOpcode() == Instruction::Sub &&
- TI->getOpcode() == Instruction::Add) ||
- (FI->getOpcode() == Instruction::FSub &&
- TI->getOpcode() == Instruction::FAdd)) {
- AddOp = TI; SubOp = FI;
- }
-
- if (AddOp) {
- Value *OtherAddOp = 0;
- if (SubOp->getOperand(0) == AddOp->getOperand(0)) {
- OtherAddOp = AddOp->getOperand(1);
- } else if (SubOp->getOperand(0) == AddOp->getOperand(1)) {
- OtherAddOp = AddOp->getOperand(0);
- }
-
- if (OtherAddOp) {
- // So at this point we know we have (Y -> OtherAddOp):
- // select C, (add X, Y), (sub X, Z)
- Value *NegVal; // Compute -Z
- if (Constant *C = dyn_cast<Constant>(SubOp->getOperand(1))) {
- NegVal = ConstantExpr::getNeg(C);
- } else {
- NegVal = InsertNewInstBefore(
- BinaryOperator::CreateNeg(SubOp->getOperand(1),
- "tmp"), SI);
- }
-
- Value *NewTrueOp = OtherAddOp;
- Value *NewFalseOp = NegVal;
- if (AddOp != TI)
- std::swap(NewTrueOp, NewFalseOp);
- Instruction *NewSel =
- SelectInst::Create(CondVal, NewTrueOp,
- NewFalseOp, SI.getName() + ".p");
-
- NewSel = InsertNewInstBefore(NewSel, SI);
- return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel);
- }
- }
- }
-
- // See if we can fold the select into one of our operands.
- if (SI.getType()->isInteger()) {
- if (Instruction *FoldI = FoldSelectIntoOp(SI, TrueVal, FalseVal))
- return FoldI;
-
- // MAX(MAX(a, b), a) -> MAX(a, b)
- // MIN(MIN(a, b), a) -> MIN(a, b)
- // MAX(MIN(a, b), a) -> a
- // MIN(MAX(a, b), a) -> a
- Value *LHS, *RHS, *LHS2, *RHS2;
- if (SelectPatternFlavor SPF = MatchSelectPattern(&SI, LHS, RHS)) {
- if (SelectPatternFlavor SPF2 = MatchSelectPattern(LHS, LHS2, RHS2))
- if (Instruction *R = FoldSPFofSPF(cast<Instruction>(LHS),SPF2,LHS2,RHS2,
- SI, SPF, RHS))
- return R;
- if (SelectPatternFlavor SPF2 = MatchSelectPattern(RHS, LHS2, RHS2))
- if (Instruction *R = FoldSPFofSPF(cast<Instruction>(RHS),SPF2,LHS2,RHS2,
- SI, SPF, LHS))
- return R;
- }
-
- // TODO.
- // ABS(-X) -> ABS(X)
- // ABS(ABS(X)) -> ABS(X)
- }
-
- // See if we can fold the select into a phi node if the condition is a select.
- if (isa<PHINode>(SI.getCondition()))
- // The true/false values have to be live in the PHI predecessor's blocks.
- if (CanSelectOperandBeMappingIntoPredBlock(TrueVal, SI) &&
- CanSelectOperandBeMappingIntoPredBlock(FalseVal, SI))
- if (Instruction *NV = FoldOpIntoPhi(SI))
- return NV;
-
- if (BinaryOperator::isNot(CondVal)) {
- SI.setOperand(0, BinaryOperator::getNotArgument(CondVal));
- SI.setOperand(1, FalseVal);
- SI.setOperand(2, TrueVal);
- return &SI;
- }
-
- return 0;
-}
-
-/// EnforceKnownAlignment - If the specified pointer points to an object that
-/// we control, modify the object's alignment to PrefAlign. This isn't
-/// often possible though. If alignment is important, a more reliable approach
-/// is to simply align all global variables and allocation instructions to
-/// their preferred alignment from the beginning.
-///
-static unsigned EnforceKnownAlignment(Value *V,
- unsigned Align, unsigned PrefAlign) {
-
- User *U = dyn_cast<User>(V);
- if (!U) return Align;
-
- switch (Operator::getOpcode(U)) {
- default: break;
- case Instruction::BitCast:
- return EnforceKnownAlignment(U->getOperand(0), Align, PrefAlign);
- case Instruction::GetElementPtr: {
- // If all indexes are zero, it is just the alignment of the base pointer.
- bool AllZeroOperands = true;
- for (User::op_iterator i = U->op_begin() + 1, e = U->op_end(); i != e; ++i)
- if (!isa<Constant>(*i) ||
- !cast<Constant>(*i)->isNullValue()) {
- AllZeroOperands = false;
- break;
- }
-
- if (AllZeroOperands) {
- // Treat this like a bitcast.
- return EnforceKnownAlignment(U->getOperand(0), Align, PrefAlign);
- }
- break;
- }
- }
-
- if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
- // If there is a large requested alignment and we can, bump up the alignment
- // of the global.
- if (!GV->isDeclaration()) {
- if (GV->getAlignment() >= PrefAlign)
- Align = GV->getAlignment();
- else {
- GV->setAlignment(PrefAlign);
- Align = PrefAlign;
- }
- }
- } else if (AllocaInst *AI = dyn_cast<AllocaInst>(V)) {
- // If there is a requested alignment and if this is an alloca, round up.
- if (AI->getAlignment() >= PrefAlign)
- Align = AI->getAlignment();
- else {
- AI->setAlignment(PrefAlign);
- Align = PrefAlign;
- }
- }
-
- return Align;
-}
-
-/// GetOrEnforceKnownAlignment - If the specified pointer has an alignment that
-/// we can determine, return it, otherwise return 0. If PrefAlign is specified,
-/// and it is more than the alignment of the ultimate object, see if we can
-/// increase the alignment of the ultimate object, making this check succeed.
-unsigned InstCombiner::GetOrEnforceKnownAlignment(Value *V,
- unsigned PrefAlign) {
- unsigned BitWidth = TD ? TD->getTypeSizeInBits(V->getType()) :
- sizeof(PrefAlign) * CHAR_BIT;
- APInt Mask = APInt::getAllOnesValue(BitWidth);
- APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
- ComputeMaskedBits(V, Mask, KnownZero, KnownOne);
- unsigned TrailZ = KnownZero.countTrailingOnes();
- unsigned Align = 1u << std::min(BitWidth - 1, TrailZ);
-
- if (PrefAlign > Align)
- Align = EnforceKnownAlignment(V, Align, PrefAlign);
-
- // We don't need to make any adjustment.
- return Align;
-}
-
-Instruction *InstCombiner::SimplifyMemTransfer(MemIntrinsic *MI) {
- unsigned DstAlign = GetOrEnforceKnownAlignment(MI->getOperand(1));
- unsigned SrcAlign = GetOrEnforceKnownAlignment(MI->getOperand(2));
- unsigned MinAlign = std::min(DstAlign, SrcAlign);
- unsigned CopyAlign = MI->getAlignment();
-
- if (CopyAlign < MinAlign) {
- MI->setAlignment(ConstantInt::get(MI->getAlignmentType(),
- MinAlign, false));
- return MI;
- }
-
- // If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with
- // load/store.
- ConstantInt *MemOpLength = dyn_cast<ConstantInt>(MI->getOperand(3));
- if (MemOpLength == 0) return 0;
-
- // Source and destination pointer types are always "i8*" for intrinsic. See
- // if the size is something we can handle with a single primitive load/store.
- // A single load+store correctly handles overlapping memory in the memmove
- // case.
- unsigned Size = MemOpLength->getZExtValue();
- if (Size == 0) return MI; // Delete this mem transfer.
-
- if (Size > 8 || (Size&(Size-1)))
- return 0; // If not 1/2/4/8 bytes, exit.
-
- // Use an integer load+store unless we can find something better.
- Type *NewPtrTy =
- PointerType::getUnqual(IntegerType::get(MI->getContext(), Size<<3));
-
- // Memcpy forces the use of i8* for the source and destination. That means
- // that if you're using memcpy to move one double around, you'll get a cast
- // from double* to i8*. We'd much rather use a double load+store rather than
- // an i64 load+store, here because this improves the odds that the source or
- // dest address will be promotable. See if we can find a better type than the
- // integer datatype.
- if (Value *Op = getBitCastOperand(MI->getOperand(1))) {
- const Type *SrcETy = cast<PointerType>(Op->getType())->getElementType();
- if (TD && SrcETy->isSized() && TD->getTypeStoreSize(SrcETy) == Size) {
- // The SrcETy might be something like {{{double}}} or [1 x double]. Rip
- // down through these levels if so.
- while (!SrcETy->isSingleValueType()) {
- if (const StructType *STy = dyn_cast<StructType>(SrcETy)) {
- if (STy->getNumElements() == 1)
- SrcETy = STy->getElementType(0);
- else
- break;
- } else if (const ArrayType *ATy = dyn_cast<ArrayType>(SrcETy)) {
- if (ATy->getNumElements() == 1)
- SrcETy = ATy->getElementType();
- else
- break;
- } else
- break;
- }
-
- if (SrcETy->isSingleValueType())
- NewPtrTy = PointerType::getUnqual(SrcETy);
- }
- }
-
-
- // If the memcpy/memmove provides better alignment info than we can
- // infer, use it.
- SrcAlign = std::max(SrcAlign, CopyAlign);
- DstAlign = std::max(DstAlign, CopyAlign);
-
- Value *Src = Builder->CreateBitCast(MI->getOperand(2), NewPtrTy);
- Value *Dest = Builder->CreateBitCast(MI->getOperand(1), NewPtrTy);
- Instruction *L = new LoadInst(Src, "tmp", false, SrcAlign);
- InsertNewInstBefore(L, *MI);
- InsertNewInstBefore(new StoreInst(L, Dest, false, DstAlign), *MI);
-
- // Set the size of the copy to 0, it will be deleted on the next iteration.
- MI->setOperand(3, Constant::getNullValue(MemOpLength->getType()));
- return MI;
-}
-
-Instruction *InstCombiner::SimplifyMemSet(MemSetInst *MI) {
- unsigned Alignment = GetOrEnforceKnownAlignment(MI->getDest());
- if (MI->getAlignment() < Alignment) {
- MI->setAlignment(ConstantInt::get(MI->getAlignmentType(),
- Alignment, false));
- return MI;
- }
-
- // Extract the length and alignment and fill if they are constant.
- ConstantInt *LenC = dyn_cast<ConstantInt>(MI->getLength());
- ConstantInt *FillC = dyn_cast<ConstantInt>(MI->getValue());
- if (!LenC || !FillC || FillC->getType() != Type::getInt8Ty(MI->getContext()))
- return 0;
- uint64_t Len = LenC->getZExtValue();
- Alignment = MI->getAlignment();
-
- // If the length is zero, this is a no-op
- if (Len == 0) return MI; // memset(d,c,0,a) -> noop
-
- // memset(s,c,n) -> store s, c (for n=1,2,4,8)
- if (Len <= 8 && isPowerOf2_32((uint32_t)Len)) {
- const Type *ITy = IntegerType::get(MI->getContext(), Len*8); // n=1 -> i8.
-
- Value *Dest = MI->getDest();
- Dest = Builder->CreateBitCast(Dest, PointerType::getUnqual(ITy));
-
- // Alignment 0 is identity for alignment 1 for memset, but not store.
- if (Alignment == 0) Alignment = 1;
-
- // Extract the fill value and store.
- uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL;
- InsertNewInstBefore(new StoreInst(ConstantInt::get(ITy, Fill),
- Dest, false, Alignment), *MI);
-
- // Set the size of the copy to 0, it will be deleted on the next iteration.
- MI->setLength(Constant::getNullValue(LenC->getType()));
- return MI;
- }
-
- return 0;
-}
-
-
-/// visitCallInst - CallInst simplification. This mostly only handles folding
-/// of intrinsic instructions. For normal calls, it allows visitCallSite to do
-/// the heavy lifting.
-///
-Instruction *InstCombiner::visitCallInst(CallInst &CI) {
- if (isFreeCall(&CI))
- return visitFree(CI);
-
- // If the caller function is nounwind, mark the call as nounwind, even if the
- // callee isn't.
- if (CI.getParent()->getParent()->doesNotThrow() &&
- !CI.doesNotThrow()) {
- CI.setDoesNotThrow();
- return &CI;
- }
-
- IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI);
- if (!II) return visitCallSite(&CI);
-
- // Intrinsics cannot occur in an invoke, so handle them here instead of in
- // visitCallSite.
- if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(II)) {
- bool Changed = false;
-
- // memmove/cpy/set of zero bytes is a noop.
- if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) {
- if (NumBytes->isNullValue()) return EraseInstFromFunction(CI);
-
- if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes))
- if (CI->getZExtValue() == 1) {
- // Replace the instruction with just byte operations. We would
- // transform other cases to loads/stores, but we don't know if
- // alignment is sufficient.
- }
- }
-
- // If we have a memmove and the source operation is a constant global,
- // then the source and dest pointers can't alias, so we can change this
- // into a call to memcpy.
- if (MemMoveInst *MMI = dyn_cast<MemMoveInst>(MI)) {
- if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource()))
- if (GVSrc->isConstant()) {
- Module *M = CI.getParent()->getParent()->getParent();
- Intrinsic::ID MemCpyID = Intrinsic::memcpy;
- const Type *Tys[1];
- Tys[0] = CI.getOperand(3)->getType();
- CI.setOperand(0,
- Intrinsic::getDeclaration(M, MemCpyID, Tys, 1));
- Changed = true;
- }
- }
-
- if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
- // memmove(x,x,size) -> noop.
- if (MTI->getSource() == MTI->getDest())
- return EraseInstFromFunction(CI);
- }
-
- // If we can determine a pointer alignment that is bigger than currently
- // set, update the alignment.
- if (isa<MemTransferInst>(MI)) {
- if (Instruction *I = SimplifyMemTransfer(MI))
- return I;
- } else if (MemSetInst *MSI = dyn_cast<MemSetInst>(MI)) {
- if (Instruction *I = SimplifyMemSet(MSI))
- return I;
- }
-
- if (Changed) return II;
- }
-
- switch (II->getIntrinsicID()) {
- default: break;
- case Intrinsic::bswap:
- // bswap(bswap(x)) -> x
- if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(II->getOperand(1)))
- if (Operand->getIntrinsicID() == Intrinsic::bswap)
- return ReplaceInstUsesWith(CI, Operand->getOperand(1));
-
- // bswap(trunc(bswap(x))) -> trunc(lshr(x, c))
- if (TruncInst *TI = dyn_cast<TruncInst>(II->getOperand(1))) {
- if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(TI->getOperand(0)))
- if (Operand->getIntrinsicID() == Intrinsic::bswap) {
- unsigned C = Operand->getType()->getPrimitiveSizeInBits() -
- TI->getType()->getPrimitiveSizeInBits();
- Value *CV = ConstantInt::get(Operand->getType(), C);
- Value *V = Builder->CreateLShr(Operand->getOperand(1), CV);
- return new TruncInst(V, TI->getType());
- }
- }
-
- break;
- case Intrinsic::powi:
- if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getOperand(2))) {
- // powi(x, 0) -> 1.0
- if (Power->isZero())
- return ReplaceInstUsesWith(CI, ConstantFP::get(CI.getType(), 1.0));
- // powi(x, 1) -> x
- if (Power->isOne())
- return ReplaceInstUsesWith(CI, II->getOperand(1));
- // powi(x, -1) -> 1/x
- if (Power->isAllOnesValue())
- return BinaryOperator::CreateFDiv(ConstantFP::get(CI.getType(), 1.0),
- II->getOperand(1));
- }
- break;
-
- case Intrinsic::uadd_with_overflow: {
- Value *LHS = II->getOperand(1), *RHS = II->getOperand(2);
- const IntegerType *IT = cast<IntegerType>(II->getOperand(1)->getType());
- uint32_t BitWidth = IT->getBitWidth();
- APInt Mask = APInt::getSignBit(BitWidth);
- APInt LHSKnownZero(BitWidth, 0);
- APInt LHSKnownOne(BitWidth, 0);
- ComputeMaskedBits(LHS, Mask, LHSKnownZero, LHSKnownOne);
- bool LHSKnownNegative = LHSKnownOne[BitWidth - 1];
- bool LHSKnownPositive = LHSKnownZero[BitWidth - 1];
-
- if (LHSKnownNegative || LHSKnownPositive) {
- APInt RHSKnownZero(BitWidth, 0);
- APInt RHSKnownOne(BitWidth, 0);
- ComputeMaskedBits(RHS, Mask, RHSKnownZero, RHSKnownOne);
- bool RHSKnownNegative = RHSKnownOne[BitWidth - 1];
- bool RHSKnownPositive = RHSKnownZero[BitWidth - 1];
- if (LHSKnownNegative && RHSKnownNegative) {
- // The sign bit is set in both cases: this MUST overflow.
- // Create a simple add instruction, and insert it into the struct.
- Instruction *Add = BinaryOperator::CreateAdd(LHS, RHS, "", &CI);
- Worklist.Add(Add);
- Constant *V[] = {
- UndefValue::get(LHS->getType()),ConstantInt::getTrue(II->getContext())
- };
- Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false);
- return InsertValueInst::Create(Struct, Add, 0);
- }
-
- if (LHSKnownPositive && RHSKnownPositive) {
- // The sign bit is clear in both cases: this CANNOT overflow.
- // Create a simple add instruction, and insert it into the struct.
- Instruction *Add = BinaryOperator::CreateNUWAdd(LHS, RHS, "", &CI);
- Worklist.Add(Add);
- Constant *V[] = {
- UndefValue::get(LHS->getType()),
- ConstantInt::getFalse(II->getContext())
- };
- Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false);
- return InsertValueInst::Create(Struct, Add, 0);
- }
- }
- }
- // FALL THROUGH uadd into sadd
- case Intrinsic::sadd_with_overflow:
- // Canonicalize constants into the RHS.
- if (isa<Constant>(II->getOperand(1)) &&
- !isa<Constant>(II->getOperand(2))) {
- Value *LHS = II->getOperand(1);
- II->setOperand(1, II->getOperand(2));
- II->setOperand(2, LHS);
- return II;
- }
-
- // X + undef -> undef
- if (isa<UndefValue>(II->getOperand(2)))
- return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
-
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getOperand(2))) {
- // X + 0 -> {X, false}
- if (RHS->isZero()) {
- Constant *V[] = {
- UndefValue::get(II->getOperand(0)->getType()),
- ConstantInt::getFalse(II->getContext())
- };
- Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false);
- return InsertValueInst::Create(Struct, II->getOperand(1), 0);
- }
- }
- break;
- case Intrinsic::usub_with_overflow:
- case Intrinsic::ssub_with_overflow:
- // undef - X -> undef
- // X - undef -> undef
- if (isa<UndefValue>(II->getOperand(1)) ||
- isa<UndefValue>(II->getOperand(2)))
- return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
-
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getOperand(2))) {
- // X - 0 -> {X, false}
- if (RHS->isZero()) {
- Constant *V[] = {
- UndefValue::get(II->getOperand(1)->getType()),
- ConstantInt::getFalse(II->getContext())
- };
- Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false);
- return InsertValueInst::Create(Struct, II->getOperand(1), 0);
- }
- }
- break;
- case Intrinsic::umul_with_overflow:
- case Intrinsic::smul_with_overflow:
- // Canonicalize constants into the RHS.
- if (isa<Constant>(II->getOperand(1)) &&
- !isa<Constant>(II->getOperand(2))) {
- Value *LHS = II->getOperand(1);
- II->setOperand(1, II->getOperand(2));
- II->setOperand(2, LHS);
- return II;
- }
-
- // X * undef -> undef
- if (isa<UndefValue>(II->getOperand(2)))
- return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
-
- if (ConstantInt *RHSI = dyn_cast<ConstantInt>(II->getOperand(2))) {
- // X*0 -> {0, false}
- if (RHSI->isZero())
- return ReplaceInstUsesWith(CI, Constant::getNullValue(II->getType()));
-
- // X * 1 -> {X, false}
- if (RHSI->equalsInt(1)) {
- Constant *V[] = {
- UndefValue::get(II->getOperand(1)->getType()),
- ConstantInt::getFalse(II->getContext())
- };
- Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false);
- return InsertValueInst::Create(Struct, II->getOperand(1), 0);
- }
- }
- break;
- case Intrinsic::ppc_altivec_lvx:
- case Intrinsic::ppc_altivec_lvxl:
- case Intrinsic::x86_sse_loadu_ps:
- case Intrinsic::x86_sse2_loadu_pd:
- case Intrinsic::x86_sse2_loadu_dq:
- // Turn PPC lvx -> load if the pointer is known aligned.
- // Turn X86 loadups -> load if the pointer is known aligned.
- if (GetOrEnforceKnownAlignment(II->getOperand(1), 16) >= 16) {
- Value *Ptr = Builder->CreateBitCast(II->getOperand(1),
- PointerType::getUnqual(II->getType()));
- return new LoadInst(Ptr);
- }
- break;
- case Intrinsic::ppc_altivec_stvx:
- case Intrinsic::ppc_altivec_stvxl:
- // Turn stvx -> store if the pointer is known aligned.
- if (GetOrEnforceKnownAlignment(II->getOperand(2), 16) >= 16) {
- const Type *OpPtrTy =
- PointerType::getUnqual(II->getOperand(1)->getType());
- Value *Ptr = Builder->CreateBitCast(II->getOperand(2), OpPtrTy);
- return new StoreInst(II->getOperand(1), Ptr);
- }
- break;
- case Intrinsic::x86_sse_storeu_ps:
- case Intrinsic::x86_sse2_storeu_pd:
- case Intrinsic::x86_sse2_storeu_dq:
- // Turn X86 storeu -> store if the pointer is known aligned.
- if (GetOrEnforceKnownAlignment(II->getOperand(1), 16) >= 16) {
- const Type *OpPtrTy =
- PointerType::getUnqual(II->getOperand(2)->getType());
- Value *Ptr = Builder->CreateBitCast(II->getOperand(1), OpPtrTy);
- return new StoreInst(II->getOperand(2), Ptr);
- }
- break;
-
- case Intrinsic::x86_sse_cvttss2si: {
- // These intrinsics only demands the 0th element of its input vector. If
- // we can simplify the input based on that, do so now.
- unsigned VWidth =
- cast<VectorType>(II->getOperand(1)->getType())->getNumElements();
- APInt DemandedElts(VWidth, 1);
- APInt UndefElts(VWidth, 0);
- if (Value *V = SimplifyDemandedVectorElts(II->getOperand(1), DemandedElts,
- UndefElts)) {
- II->setOperand(1, V);
- return II;
- }
- break;
- }
-
- case Intrinsic::ppc_altivec_vperm:
- // Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant.
- if (ConstantVector *Mask = dyn_cast<ConstantVector>(II->getOperand(3))) {
- assert(Mask->getNumOperands() == 16 && "Bad type for intrinsic!");
-
- // Check that all of the elements are integer constants or undefs.
- bool AllEltsOk = true;
- for (unsigned i = 0; i != 16; ++i) {
- if (!isa<ConstantInt>(Mask->getOperand(i)) &&
- !isa<UndefValue>(Mask->getOperand(i))) {
- AllEltsOk = false;
- break;
- }
- }
-
- if (AllEltsOk) {
- // Cast the input vectors to byte vectors.
- Value *Op0 = Builder->CreateBitCast(II->getOperand(1), Mask->getType());
- Value *Op1 = Builder->CreateBitCast(II->getOperand(2), Mask->getType());
- Value *Result = UndefValue::get(Op0->getType());
-
- // Only extract each element once.
- Value *ExtractedElts[32];
- memset(ExtractedElts, 0, sizeof(ExtractedElts));
-
- for (unsigned i = 0; i != 16; ++i) {
- if (isa<UndefValue>(Mask->getOperand(i)))
- continue;
- unsigned Idx=cast<ConstantInt>(Mask->getOperand(i))->getZExtValue();
- Idx &= 31; // Match the hardware behavior.
-
- if (ExtractedElts[Idx] == 0) {
- ExtractedElts[Idx] =
- Builder->CreateExtractElement(Idx < 16 ? Op0 : Op1,
- ConstantInt::get(Type::getInt32Ty(II->getContext()),
- Idx&15, false), "tmp");
- }
-
- // Insert this value into the result vector.
- Result = Builder->CreateInsertElement(Result, ExtractedElts[Idx],
- ConstantInt::get(Type::getInt32Ty(II->getContext()),
- i, false), "tmp");
- }
- return CastInst::Create(Instruction::BitCast, Result, CI.getType());
- }
- }
- break;
-
- case Intrinsic::stackrestore: {
- // If the save is right next to the restore, remove the restore. This can
- // happen when variable allocas are DCE'd.
- if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getOperand(1))) {
- if (SS->getIntrinsicID() == Intrinsic::stacksave) {
- BasicBlock::iterator BI = SS;
- if (&*++BI == II)
- return EraseInstFromFunction(CI);
- }
- }
-
- // Scan down this block to see if there is another stack restore in the
- // same block without an intervening call/alloca.
- BasicBlock::iterator BI = II;
- TerminatorInst *TI = II->getParent()->getTerminator();
- bool CannotRemove = false;
- for (++BI; &*BI != TI; ++BI) {
- if (isa<AllocaInst>(BI) || isMalloc(BI)) {
- CannotRemove = true;
- break;
- }
- if (CallInst *BCI = dyn_cast<CallInst>(BI)) {
- if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BCI)) {
- // If there is a stackrestore below this one, remove this one.
- if (II->getIntrinsicID() == Intrinsic::stackrestore)
- return EraseInstFromFunction(CI);
- // Otherwise, ignore the intrinsic.
- } else {
- // If we found a non-intrinsic call, we can't remove the stack
- // restore.
- CannotRemove = true;
- break;
- }
- }
- }
-
- // If the stack restore is in a return/unwind block and if there are no
- // allocas or calls between the restore and the return, nuke the restore.
- if (!CannotRemove && (isa<ReturnInst>(TI) || isa<UnwindInst>(TI)))
- return EraseInstFromFunction(CI);
- break;
- }
- }
-
- return visitCallSite(II);
-}
-
-// InvokeInst simplification
-//
-Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) {
- return visitCallSite(&II);
-}
-
-/// isSafeToEliminateVarargsCast - If this cast does not affect the value
-/// passed through the varargs area, we can eliminate the use of the cast.
-static bool isSafeToEliminateVarargsCast(const CallSite CS,
- const CastInst * const CI,
- const TargetData * const TD,
- const int ix) {
- if (!CI->isLosslessCast())
- return false;
-
- // The size of ByVal arguments is derived from the type, so we
- // can't change to a type with a different size. If the size were
- // passed explicitly we could avoid this check.
- if (!CS.paramHasAttr(ix, Attribute::ByVal))
- return true;
-
- const Type* SrcTy =
- cast<PointerType>(CI->getOperand(0)->getType())->getElementType();
- const Type* DstTy = cast<PointerType>(CI->getType())->getElementType();
- if (!SrcTy->isSized() || !DstTy->isSized())
- return false;
- if (!TD || TD->getTypeAllocSize(SrcTy) != TD->getTypeAllocSize(DstTy))
- return false;
- return true;
-}
-
-// visitCallSite - Improvements for call and invoke instructions.
-//
-Instruction *InstCombiner::visitCallSite(CallSite CS) {
- bool Changed = false;
-
- // If the callee is a constexpr cast of a function, attempt to move the cast
- // to the arguments of the call/invoke.
- if (transformConstExprCastCall(CS)) return 0;
-
- Value *Callee = CS.getCalledValue();
-
- if (Function *CalleeF = dyn_cast<Function>(Callee))
- if (CalleeF->getCallingConv() != CS.getCallingConv()) {
- Instruction *OldCall = CS.getInstruction();
- // If the call and callee calling conventions don't match, this call must
- // be unreachable, as the call is undefined.
- new StoreInst(ConstantInt::getTrue(Callee->getContext()),
- UndefValue::get(Type::getInt1PtrTy(Callee->getContext())),
- OldCall);
- // If OldCall dues not return void then replaceAllUsesWith undef.
- // This allows ValueHandlers and custom metadata to adjust itself.
- if (!OldCall->getType()->isVoidTy())
- OldCall->replaceAllUsesWith(UndefValue::get(OldCall->getType()));
- if (isa<CallInst>(OldCall)) // Not worth removing an invoke here.
- return EraseInstFromFunction(*OldCall);
- return 0;
- }
-
- if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) {
- // This instruction is not reachable, just remove it. We insert a store to
- // undef so that we know that this code is not reachable, despite the fact
- // that we can't modify the CFG here.
- new StoreInst(ConstantInt::getTrue(Callee->getContext()),
- UndefValue::get(Type::getInt1PtrTy(Callee->getContext())),
- CS.getInstruction());
-
- // If CS dues not return void then replaceAllUsesWith undef.
- // This allows ValueHandlers and custom metadata to adjust itself.
- if (!CS.getInstruction()->getType()->isVoidTy())
- CS.getInstruction()->
- replaceAllUsesWith(UndefValue::get(CS.getInstruction()->getType()));
-
- if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
- // Don't break the CFG, insert a dummy cond branch.
- BranchInst::Create(II->getNormalDest(), II->getUnwindDest(),
- ConstantInt::getTrue(Callee->getContext()), II);
- }
- return EraseInstFromFunction(*CS.getInstruction());
- }
-
- if (BitCastInst *BC = dyn_cast<BitCastInst>(Callee))
- if (IntrinsicInst *In = dyn_cast<IntrinsicInst>(BC->getOperand(0)))
- if (In->getIntrinsicID() == Intrinsic::init_trampoline)
- return transformCallThroughTrampoline(CS);
-
- const PointerType *PTy = cast<PointerType>(Callee->getType());
- const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
- if (FTy->isVarArg()) {
- int ix = FTy->getNumParams() + (isa<InvokeInst>(Callee) ? 3 : 1);
- // See if we can optimize any arguments passed through the varargs area of
- // the call.
- for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(),
- E = CS.arg_end(); I != E; ++I, ++ix) {
- CastInst *CI = dyn_cast<CastInst>(*I);
- if (CI && isSafeToEliminateVarargsCast(CS, CI, TD, ix)) {
- *I = CI->getOperand(0);
- Changed = true;
- }
- }
- }
-
- if (isa<InlineAsm>(Callee) && !CS.doesNotThrow()) {
- // Inline asm calls cannot throw - mark them 'nounwind'.
- CS.setDoesNotThrow();
- Changed = true;
- }
-
- return Changed ? CS.getInstruction() : 0;
-}
-
-// transformConstExprCastCall - If the callee is a constexpr cast of a function,
-// attempt to move the cast to the arguments of the call/invoke.
-//
-bool InstCombiner::transformConstExprCastCall(CallSite CS) {
- if (!isa<ConstantExpr>(CS.getCalledValue())) return false;
- ConstantExpr *CE = cast<ConstantExpr>(CS.getCalledValue());
- if (CE->getOpcode() != Instruction::BitCast ||
- !isa<Function>(CE->getOperand(0)))
- return false;
- Function *Callee = cast<Function>(CE->getOperand(0));
- Instruction *Caller = CS.getInstruction();
- const AttrListPtr &CallerPAL = CS.getAttributes();
-
- // Okay, this is a cast from a function to a different type. Unless doing so
- // would cause a type conversion of one of our arguments, change this call to
- // be a direct call with arguments casted to the appropriate types.
- //
- const FunctionType *FT = Callee->getFunctionType();
- const Type *OldRetTy = Caller->getType();
- const Type *NewRetTy = FT->getReturnType();
-
- if (isa<StructType>(NewRetTy))
- return false; // TODO: Handle multiple return values.
-
- // Check to see if we are changing the return type...
- if (OldRetTy != NewRetTy) {
- if (Callee->isDeclaration() &&
- // Conversion is ok if changing from one pointer type to another or from
- // a pointer to an integer of the same size.
- !((isa<PointerType>(OldRetTy) || !TD ||
- OldRetTy == TD->getIntPtrType(Caller->getContext())) &&
- (isa<PointerType>(NewRetTy) || !TD ||
- NewRetTy == TD->getIntPtrType(Caller->getContext()))))
- return false; // Cannot transform this return value.
-
- if (!Caller->use_empty() &&
- // void -> non-void is handled specially
- !NewRetTy->isVoidTy() && !CastInst::isCastable(NewRetTy, OldRetTy))
- return false; // Cannot transform this return value.
-
- if (!CallerPAL.isEmpty() && !Caller->use_empty()) {
- Attributes RAttrs = CallerPAL.getRetAttributes();
- if (RAttrs & Attribute::typeIncompatible(NewRetTy))
- return false; // Attribute not compatible with transformed value.
- }
-
- // If the callsite is an invoke instruction, and the return value is used by
- // a PHI node in a successor, we cannot change the return type of the call
- // because there is no place to put the cast instruction (without breaking
- // the critical edge). Bail out in this case.
- if (!Caller->use_empty())
- if (InvokeInst *II = dyn_cast<InvokeInst>(Caller))
- for (Value::use_iterator UI = II->use_begin(), E = II->use_end();
- UI != E; ++UI)
- if (PHINode *PN = dyn_cast<PHINode>(*UI))
- if (PN->getParent() == II->getNormalDest() ||
- PN->getParent() == II->getUnwindDest())
- return false;
- }
-
- unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin());
- unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs);
-
- CallSite::arg_iterator AI = CS.arg_begin();
- for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) {
- const Type *ParamTy = FT->getParamType(i);
- const Type *ActTy = (*AI)->getType();
-
- if (!CastInst::isCastable(ActTy, ParamTy))
- return false; // Cannot transform this parameter value.
-
- if (CallerPAL.getParamAttributes(i + 1)
- & Attribute::typeIncompatible(ParamTy))
- return false; // Attribute not compatible with transformed value.
-
- // Converting from one pointer type to another or between a pointer and an
- // integer of the same size is safe even if we do not have a body.
- bool isConvertible = ActTy == ParamTy ||
- (TD && ((isa<PointerType>(ParamTy) ||
- ParamTy == TD->getIntPtrType(Caller->getContext())) &&
- (isa<PointerType>(ActTy) ||
- ActTy == TD->getIntPtrType(Caller->getContext()))));
- if (Callee->isDeclaration() && !isConvertible) return false;
- }
-
- if (FT->getNumParams() < NumActualArgs && !FT->isVarArg() &&
- Callee->isDeclaration())
- return false; // Do not delete arguments unless we have a function body.
-
- if (FT->getNumParams() < NumActualArgs && FT->isVarArg() &&
- !CallerPAL.isEmpty())
- // In this case we have more arguments than the new function type, but we
- // won't be dropping them. Check that these extra arguments have attributes
- // that are compatible with being a vararg call argument.
- for (unsigned i = CallerPAL.getNumSlots(); i; --i) {
- if (CallerPAL.getSlot(i - 1).Index <= FT->getNumParams())
- break;
- Attributes PAttrs = CallerPAL.getSlot(i - 1).Attrs;
- if (PAttrs & Attribute::VarArgsIncompatible)
- return false;
- }
-
- // Okay, we decided that this is a safe thing to do: go ahead and start
- // inserting cast instructions as necessary...
- std::vector<Value*> Args;
- Args.reserve(NumActualArgs);
- SmallVector<AttributeWithIndex, 8> attrVec;
- attrVec.reserve(NumCommonArgs);
-
- // Get any return attributes.
- Attributes RAttrs = CallerPAL.getRetAttributes();
-
- // If the return value is not being used, the type may not be compatible
- // with the existing attributes. Wipe out any problematic attributes.
- RAttrs &= ~Attribute::typeIncompatible(NewRetTy);
-
- // Add the new return attributes.
- if (RAttrs)
- attrVec.push_back(AttributeWithIndex::get(0, RAttrs));
-
- AI = CS.arg_begin();
- for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) {
- const Type *ParamTy = FT->getParamType(i);
- if ((*AI)->getType() == ParamTy) {
- Args.push_back(*AI);
- } else {
- Instruction::CastOps opcode = CastInst::getCastOpcode(*AI,
- false, ParamTy, false);
- Args.push_back(Builder->CreateCast(opcode, *AI, ParamTy, "tmp"));
- }
-
- // Add any parameter attributes.
- if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1))
- attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs));
- }
-
- // If the function takes more arguments than the call was taking, add them
- // now.
- for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i)
- Args.push_back(Constant::getNullValue(FT->getParamType(i)));
-
- // If we are removing arguments to the function, emit an obnoxious warning.
- if (FT->getNumParams() < NumActualArgs) {
- if (!FT->isVarArg()) {
- errs() << "WARNING: While resolving call to function '"
- << Callee->getName() << "' arguments were dropped!\n";
- } else {
- // Add all of the arguments in their promoted form to the arg list.
- for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) {
- const Type *PTy = getPromotedType((*AI)->getType());
- if (PTy != (*AI)->getType()) {
- // Must promote to pass through va_arg area!
- Instruction::CastOps opcode =
- CastInst::getCastOpcode(*AI, false, PTy, false);
- Args.push_back(Builder->CreateCast(opcode, *AI, PTy, "tmp"));
- } else {
- Args.push_back(*AI);
- }
-
- // Add any parameter attributes.
- if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1))
- attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs));
- }
- }
- }
-
- if (Attributes FnAttrs = CallerPAL.getFnAttributes())
- attrVec.push_back(AttributeWithIndex::get(~0, FnAttrs));
-
- if (NewRetTy->isVoidTy())
- Caller->setName(""); // Void type should not have a name.
-
- const AttrListPtr &NewCallerPAL = AttrListPtr::get(attrVec.begin(),
- attrVec.end());
-
- Instruction *NC;
- if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
- NC = InvokeInst::Create(Callee, II->getNormalDest(), II->getUnwindDest(),
- Args.begin(), Args.end(),
- Caller->getName(), Caller);
- cast<InvokeInst>(NC)->setCallingConv(II->getCallingConv());
- cast<InvokeInst>(NC)->setAttributes(NewCallerPAL);
- } else {
- NC = CallInst::Create(Callee, Args.begin(), Args.end(),
- Caller->getName(), Caller);
- CallInst *CI = cast<CallInst>(Caller);
- if (CI->isTailCall())
- cast<CallInst>(NC)->setTailCall();
- cast<CallInst>(NC)->setCallingConv(CI->getCallingConv());
- cast<CallInst>(NC)->setAttributes(NewCallerPAL);
- }
-
- // Insert a cast of the return type as necessary.
- Value *NV = NC;
- if (OldRetTy != NV->getType() && !Caller->use_empty()) {
- if (!NV->getType()->isVoidTy()) {
- Instruction::CastOps opcode = CastInst::getCastOpcode(NC, false,
- OldRetTy, false);
- NV = NC = CastInst::Create(opcode, NC, OldRetTy, "tmp");
-
- // If this is an invoke instruction, we should insert it after the first
- // non-phi, instruction in the normal successor block.
- if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
- BasicBlock::iterator I = II->getNormalDest()->getFirstNonPHI();
- InsertNewInstBefore(NC, *I);
- } else {
- // Otherwise, it's a call, just insert cast right after the call instr
- InsertNewInstBefore(NC, *Caller);
- }
- Worklist.AddUsersToWorkList(*Caller);
- } else {
- NV = UndefValue::get(Caller->getType());
- }
- }
-
-
- if (!Caller->use_empty())
- Caller->replaceAllUsesWith(NV);
-
- EraseInstFromFunction(*Caller);
- return true;
-}
-
-// transformCallThroughTrampoline - Turn a call to a function created by the
-// init_trampoline intrinsic into a direct call to the underlying function.
-//
-Instruction *InstCombiner::transformCallThroughTrampoline(CallSite CS) {
- Value *Callee = CS.getCalledValue();
- const PointerType *PTy = cast<PointerType>(Callee->getType());
- const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
- const AttrListPtr &Attrs = CS.getAttributes();
-
- // If the call already has the 'nest' attribute somewhere then give up -
- // otherwise 'nest' would occur twice after splicing in the chain.
- if (Attrs.hasAttrSomewhere(Attribute::Nest))
- return 0;
-
- IntrinsicInst *Tramp =
- cast<IntrinsicInst>(cast<BitCastInst>(Callee)->getOperand(0));
-
- Function *NestF = cast<Function>(Tramp->getOperand(2)->stripPointerCasts());
- const PointerType *NestFPTy = cast<PointerType>(NestF->getType());
- const FunctionType *NestFTy = cast<FunctionType>(NestFPTy->getElementType());
-
- const AttrListPtr &NestAttrs = NestF->getAttributes();
- if (!NestAttrs.isEmpty()) {
- unsigned NestIdx = 1;
- const Type *NestTy = 0;
- Attributes NestAttr = Attribute::None;
-
- // Look for a parameter marked with the 'nest' attribute.
- for (FunctionType::param_iterator I = NestFTy->param_begin(),
- E = NestFTy->param_end(); I != E; ++NestIdx, ++I)
- if (NestAttrs.paramHasAttr(NestIdx, Attribute::Nest)) {
- // Record the parameter type and any other attributes.
- NestTy = *I;
- NestAttr = NestAttrs.getParamAttributes(NestIdx);
- break;
- }
-
- if (NestTy) {
- Instruction *Caller = CS.getInstruction();
- std::vector<Value*> NewArgs;
- NewArgs.reserve(unsigned(CS.arg_end()-CS.arg_begin())+1);
-
- SmallVector<AttributeWithIndex, 8> NewAttrs;
- NewAttrs.reserve(Attrs.getNumSlots() + 1);
-
- // Insert the nest argument into the call argument list, which may
- // mean appending it. Likewise for attributes.
-
- // Add any result attributes.
- if (Attributes Attr = Attrs.getRetAttributes())
- NewAttrs.push_back(AttributeWithIndex::get(0, Attr));
-
- {
- unsigned Idx = 1;
- CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
- do {
- if (Idx == NestIdx) {
- // Add the chain argument and attributes.
- Value *NestVal = Tramp->getOperand(3);
- if (NestVal->getType() != NestTy)
- NestVal = new BitCastInst(NestVal, NestTy, "nest", Caller);
- NewArgs.push_back(NestVal);
- NewAttrs.push_back(AttributeWithIndex::get(NestIdx, NestAttr));
- }
-
- if (I == E)
- break;
-
- // Add the original argument and attributes.
- NewArgs.push_back(*I);
- if (Attributes Attr = Attrs.getParamAttributes(Idx))
- NewAttrs.push_back
- (AttributeWithIndex::get(Idx + (Idx >= NestIdx), Attr));
-
- ++Idx, ++I;
- } while (1);
- }
-
- // Add any function attributes.
- if (Attributes Attr = Attrs.getFnAttributes())
- NewAttrs.push_back(AttributeWithIndex::get(~0, Attr));
-
- // The trampoline may have been bitcast to a bogus type (FTy).
- // Handle this by synthesizing a new function type, equal to FTy
- // with the chain parameter inserted.
-
- std::vector<const Type*> NewTypes;
- NewTypes.reserve(FTy->getNumParams()+1);
-
- // Insert the chain's type into the list of parameter types, which may
- // mean appending it.
- {
- unsigned Idx = 1;
- FunctionType::param_iterator I = FTy->param_begin(),
- E = FTy->param_end();
-
- do {
- if (Idx == NestIdx)
- // Add the chain's type.
- NewTypes.push_back(NestTy);
-
- if (I == E)
- break;
-
- // Add the original type.
- NewTypes.push_back(*I);
-
- ++Idx, ++I;
- } while (1);
- }
-
- // Replace the trampoline call with a direct call. Let the generic
- // code sort out any function type mismatches.
- FunctionType *NewFTy = FunctionType::get(FTy->getReturnType(), NewTypes,
- FTy->isVarArg());
- Constant *NewCallee =
- NestF->getType() == PointerType::getUnqual(NewFTy) ?
- NestF : ConstantExpr::getBitCast(NestF,
- PointerType::getUnqual(NewFTy));
- const AttrListPtr &NewPAL = AttrListPtr::get(NewAttrs.begin(),
- NewAttrs.end());
-
- Instruction *NewCaller;
- if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
- NewCaller = InvokeInst::Create(NewCallee,
- II->getNormalDest(), II->getUnwindDest(),
- NewArgs.begin(), NewArgs.end(),
- Caller->getName(), Caller);
- cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv());
- cast<InvokeInst>(NewCaller)->setAttributes(NewPAL);
- } else {
- NewCaller = CallInst::Create(NewCallee, NewArgs.begin(), NewArgs.end(),
- Caller->getName(), Caller);
- if (cast<CallInst>(Caller)->isTailCall())
- cast<CallInst>(NewCaller)->setTailCall();
- cast<CallInst>(NewCaller)->
- setCallingConv(cast<CallInst>(Caller)->getCallingConv());
- cast<CallInst>(NewCaller)->setAttributes(NewPAL);
- }
- if (!Caller->getType()->isVoidTy())
- Caller->replaceAllUsesWith(NewCaller);
- Caller->eraseFromParent();
- Worklist.Remove(Caller);
- return 0;
- }
- }
-
- // Replace the trampoline call with a direct call. Since there is no 'nest'
- // parameter, there is no need to adjust the argument list. Let the generic
- // code sort out any function type mismatches.
- Constant *NewCallee =
- NestF->getType() == PTy ? NestF :
- ConstantExpr::getBitCast(NestF, PTy);
- CS.setCalledFunction(NewCallee);
- return CS.getInstruction();
-}
-
-/// FoldPHIArgBinOpIntoPHI - If we have something like phi [add (a,b), add(a,c)]
-/// and if a/b/c and the add's all have a single use, turn this into a phi
-/// and a single binop.
-Instruction *InstCombiner::FoldPHIArgBinOpIntoPHI(PHINode &PN) {
- Instruction *FirstInst = cast<Instruction>(PN.getIncomingValue(0));
- assert(isa<BinaryOperator>(FirstInst) || isa<CmpInst>(FirstInst));
- unsigned Opc = FirstInst->getOpcode();
- Value *LHSVal = FirstInst->getOperand(0);
- Value *RHSVal = FirstInst->getOperand(1);
-
- const Type *LHSType = LHSVal->getType();
- const Type *RHSType = RHSVal->getType();
-
- // Scan to see if all operands are the same opcode, and all have one use.
- for (unsigned i = 1; i != PN.getNumIncomingValues(); ++i) {
- Instruction *I = dyn_cast<Instruction>(PN.getIncomingValue(i));
- if (!I || I->getOpcode() != Opc || !I->hasOneUse() ||
- // Verify type of the LHS matches so we don't fold cmp's of different
- // types or GEP's with different index types.
- I->getOperand(0)->getType() != LHSType ||
- I->getOperand(1)->getType() != RHSType)
- return 0;
-
- // If they are CmpInst instructions, check their predicates
- if (Opc == Instruction::ICmp || Opc == Instruction::FCmp)
- if (cast<CmpInst>(I)->getPredicate() !=
- cast<CmpInst>(FirstInst)->getPredicate())
- return 0;
-
- // Keep track of which operand needs a phi node.
- if (I->getOperand(0) != LHSVal) LHSVal = 0;
- if (I->getOperand(1) != RHSVal) RHSVal = 0;
- }
-
- // If both LHS and RHS would need a PHI, don't do this transformation,
- // because it would increase the number of PHIs entering the block,
- // which leads to higher register pressure. This is especially
- // bad when the PHIs are in the header of a loop.
- if (!LHSVal && !RHSVal)
- return 0;
-
- // Otherwise, this is safe to transform!
-
- Value *InLHS = FirstInst->getOperand(0);
- Value *InRHS = FirstInst->getOperand(1);
- PHINode *NewLHS = 0, *NewRHS = 0;
- if (LHSVal == 0) {
- NewLHS = PHINode::Create(LHSType,
- FirstInst->getOperand(0)->getName() + ".pn");
- NewLHS->reserveOperandSpace(PN.getNumOperands()/2);
- NewLHS->addIncoming(InLHS, PN.getIncomingBlock(0));
- InsertNewInstBefore(NewLHS, PN);
- LHSVal = NewLHS;
- }
-
- if (RHSVal == 0) {
- NewRHS = PHINode::Create(RHSType,
- FirstInst->getOperand(1)->getName() + ".pn");
- NewRHS->reserveOperandSpace(PN.getNumOperands()/2);
- NewRHS->addIncoming(InRHS, PN.getIncomingBlock(0));
- InsertNewInstBefore(NewRHS, PN);
- RHSVal = NewRHS;
- }
-
- // Add all operands to the new PHIs.
- if (NewLHS || NewRHS) {
- for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
- Instruction *InInst = cast<Instruction>(PN.getIncomingValue(i));
- if (NewLHS) {
- Value *NewInLHS = InInst->getOperand(0);
- NewLHS->addIncoming(NewInLHS, PN.getIncomingBlock(i));
- }
- if (NewRHS) {
- Value *NewInRHS = InInst->getOperand(1);
- NewRHS->addIncoming(NewInRHS, PN.getIncomingBlock(i));
- }
- }
- }
-
- if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(FirstInst))
- return BinaryOperator::Create(BinOp->getOpcode(), LHSVal, RHSVal);
- CmpInst *CIOp = cast<CmpInst>(FirstInst);
- return CmpInst::Create(CIOp->getOpcode(), CIOp->getPredicate(),
- LHSVal, RHSVal);
-}
-
-Instruction *InstCombiner::FoldPHIArgGEPIntoPHI(PHINode &PN) {
- GetElementPtrInst *FirstInst =cast<GetElementPtrInst>(PN.getIncomingValue(0));
-
- SmallVector<Value*, 16> FixedOperands(FirstInst->op_begin(),
- FirstInst->op_end());
- // This is true if all GEP bases are allocas and if all indices into them are
- // constants.
- bool AllBasePointersAreAllocas = true;
-
- // We don't want to replace this phi if the replacement would require
- // more than one phi, which leads to higher register pressure. This is
- // especially bad when the PHIs are in the header of a loop.
- bool NeededPhi = false;
-
- // Scan to see if all operands are the same opcode, and all have one use.
- for (unsigned i = 1; i != PN.getNumIncomingValues(); ++i) {
- GetElementPtrInst *GEP= dyn_cast<GetElementPtrInst>(PN.getIncomingValue(i));
- if (!GEP || !GEP->hasOneUse() || GEP->getType() != FirstInst->getType() ||
- GEP->getNumOperands() != FirstInst->getNumOperands())
- return 0;
-
- // Keep track of whether or not all GEPs are of alloca pointers.
- if (AllBasePointersAreAllocas &&
- (!isa<AllocaInst>(GEP->getOperand(0)) ||
- !GEP->hasAllConstantIndices()))
- AllBasePointersAreAllocas = false;
-
- // Compare the operand lists.
- for (unsigned op = 0, e = FirstInst->getNumOperands(); op != e; ++op) {
- if (FirstInst->getOperand(op) == GEP->getOperand(op))
- continue;
-
- // Don't merge two GEPs when two operands differ (introducing phi nodes)
- // if one of the PHIs has a constant for the index. The index may be
- // substantially cheaper to compute for the constants, so making it a
- // variable index could pessimize the path. This also handles the case
- // for struct indices, which must always be constant.
- if (isa<ConstantInt>(FirstInst->getOperand(op)) ||
- isa<ConstantInt>(GEP->getOperand(op)))
- return 0;
-
- if (FirstInst->getOperand(op)->getType() !=GEP->getOperand(op)->getType())
- return 0;
-
- // If we already needed a PHI for an earlier operand, and another operand
- // also requires a PHI, we'd be introducing more PHIs than we're
- // eliminating, which increases register pressure on entry to the PHI's
- // block.
- if (NeededPhi)
- return 0;
-
- FixedOperands[op] = 0; // Needs a PHI.
- NeededPhi = true;
- }
- }
-
- // If all of the base pointers of the PHI'd GEPs are from allocas, don't
- // bother doing this transformation. At best, this will just save a bit of
- // offset calculation, but all the predecessors will have to materialize the
- // stack address into a register anyway. We'd actually rather *clone* the
- // load up into the predecessors so that we have a load of a gep of an alloca,
- // which can usually all be folded into the load.
- if (AllBasePointersAreAllocas)
- return 0;
-
- // Otherwise, this is safe to transform. Insert PHI nodes for each operand
- // that is variable.
- SmallVector<PHINode*, 16> OperandPhis(FixedOperands.size());
-
- bool HasAnyPHIs = false;
- for (unsigned i = 0, e = FixedOperands.size(); i != e; ++i) {
- if (FixedOperands[i]) continue; // operand doesn't need a phi.
- Value *FirstOp = FirstInst->getOperand(i);
- PHINode *NewPN = PHINode::Create(FirstOp->getType(),
- FirstOp->getName()+".pn");
- InsertNewInstBefore(NewPN, PN);
-
- NewPN->reserveOperandSpace(e);
- NewPN->addIncoming(FirstOp, PN.getIncomingBlock(0));
- OperandPhis[i] = NewPN;
- FixedOperands[i] = NewPN;
- HasAnyPHIs = true;
- }
-
-
- // Add all operands to the new PHIs.
- if (HasAnyPHIs) {
- for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
- GetElementPtrInst *InGEP =cast<GetElementPtrInst>(PN.getIncomingValue(i));
- BasicBlock *InBB = PN.getIncomingBlock(i);
-
- for (unsigned op = 0, e = OperandPhis.size(); op != e; ++op)
- if (PHINode *OpPhi = OperandPhis[op])
- OpPhi->addIncoming(InGEP->getOperand(op), InBB);
- }
- }
-
- Value *Base = FixedOperands[0];
- return cast<GEPOperator>(FirstInst)->isInBounds() ?
- GetElementPtrInst::CreateInBounds(Base, FixedOperands.begin()+1,
- FixedOperands.end()) :
- GetElementPtrInst::Create(Base, FixedOperands.begin()+1,
- FixedOperands.end());
-}
-
-
-/// isSafeAndProfitableToSinkLoad - Return true if we know that it is safe to
-/// sink the load out of the block that defines it. This means that it must be
-/// obvious the value of the load is not changed from the point of the load to
-/// the end of the block it is in.
-///
-/// Finally, it is safe, but not profitable, to sink a load targetting a
-/// non-address-taken alloca. Doing so will cause us to not promote the alloca
-/// to a register.
-static bool isSafeAndProfitableToSinkLoad(LoadInst *L) {
- BasicBlock::iterator BBI = L, E = L->getParent()->end();
-
- for (++BBI; BBI != E; ++BBI)
- if (BBI->mayWriteToMemory())
- return false;
-
- // Check for non-address taken alloca. If not address-taken already, it isn't
- // profitable to do this xform.
- if (AllocaInst *AI = dyn_cast<AllocaInst>(L->getOperand(0))) {
- bool isAddressTaken = false;
- for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
- UI != E; ++UI) {
- if (isa<LoadInst>(UI)) continue;
- if (StoreInst *SI = dyn_cast<StoreInst>(*UI)) {
- // If storing TO the alloca, then the address isn't taken.
- if (SI->getOperand(1) == AI) continue;
- }
- isAddressTaken = true;
- break;
- }
-
- if (!isAddressTaken && AI->isStaticAlloca())
- return false;
- }
-
- // If this load is a load from a GEP with a constant offset from an alloca,
- // then we don't want to sink it. In its present form, it will be
- // load [constant stack offset]. Sinking it will cause us to have to
- // materialize the stack addresses in each predecessor in a register only to
- // do a shared load from register in the successor.
- if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(L->getOperand(0)))
- if (AllocaInst *AI = dyn_cast<AllocaInst>(GEP->getOperand(0)))
- if (AI->isStaticAlloca() && GEP->hasAllConstantIndices())
- return false;
-
- return true;
-}
-
-Instruction *InstCombiner::FoldPHIArgLoadIntoPHI(PHINode &PN) {
- LoadInst *FirstLI = cast<LoadInst>(PN.getIncomingValue(0));
-
- // When processing loads, we need to propagate two bits of information to the
- // sunk load: whether it is volatile, and what its alignment is. We currently
- // don't sink loads when some have their alignment specified and some don't.
- // visitLoadInst will propagate an alignment onto the load when TD is around,
- // and if TD isn't around, we can't handle the mixed case.
- bool isVolatile = FirstLI->isVolatile();
- unsigned LoadAlignment = FirstLI->getAlignment();
-
- // We can't sink the load if the loaded value could be modified between the
- // load and the PHI.
- if (FirstLI->getParent() != PN.getIncomingBlock(0) ||
- !isSafeAndProfitableToSinkLoad(FirstLI))
- return 0;
-
- // If the PHI is of volatile loads and the load block has multiple
- // successors, sinking it would remove a load of the volatile value from
- // the path through the other successor.
- if (isVolatile &&
- FirstLI->getParent()->getTerminator()->getNumSuccessors() != 1)
- return 0;
-
- // Check to see if all arguments are the same operation.
- for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
- LoadInst *LI = dyn_cast<LoadInst>(PN.getIncomingValue(i));
- if (!LI || !LI->hasOneUse())
- return 0;
-
- // We can't sink the load if the loaded value could be modified between
- // the load and the PHI.
- if (LI->isVolatile() != isVolatile ||
- LI->getParent() != PN.getIncomingBlock(i) ||
- !isSafeAndProfitableToSinkLoad(LI))
- return 0;
-
- // If some of the loads have an alignment specified but not all of them,
- // we can't do the transformation.
- if ((LoadAlignment != 0) != (LI->getAlignment() != 0))
- return 0;
-
- LoadAlignment = std::min(LoadAlignment, LI->getAlignment());
-
- // If the PHI is of volatile loads and the load block has multiple
- // successors, sinking it would remove a load of the volatile value from
- // the path through the other successor.
- if (isVolatile &&
- LI->getParent()->getTerminator()->getNumSuccessors() != 1)
- return 0;
- }
-
- // Okay, they are all the same operation. Create a new PHI node of the
- // correct type, and PHI together all of the LHS's of the instructions.
- PHINode *NewPN = PHINode::Create(FirstLI->getOperand(0)->getType(),
- PN.getName()+".in");
- NewPN->reserveOperandSpace(PN.getNumOperands()/2);
-
- Value *InVal = FirstLI->getOperand(0);
- NewPN->addIncoming(InVal, PN.getIncomingBlock(0));
-
- // Add all operands to the new PHI.
- for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
- Value *NewInVal = cast<LoadInst>(PN.getIncomingValue(i))->getOperand(0);
- if (NewInVal != InVal)
- InVal = 0;
- NewPN->addIncoming(NewInVal, PN.getIncomingBlock(i));
- }
-
- Value *PhiVal;
- if (InVal) {
- // The new PHI unions all of the same values together. This is really
- // common, so we handle it intelligently here for compile-time speed.
- PhiVal = InVal;
- delete NewPN;
- } else {
- InsertNewInstBefore(NewPN, PN);
- PhiVal = NewPN;
- }
-
- // If this was a volatile load that we are merging, make sure to loop through
- // and mark all the input loads as non-volatile. If we don't do this, we will
- // insert a new volatile load and the old ones will not be deletable.
- if (isVolatile)
- for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
- cast<LoadInst>(PN.getIncomingValue(i))->setVolatile(false);
-
- return new LoadInst(PhiVal, "", isVolatile, LoadAlignment);
-}
-
-
-
-/// FoldPHIArgOpIntoPHI - If all operands to a PHI node are the same "unary"
-/// operator and they all are only used by the PHI, PHI together their
-/// inputs, and do the operation once, to the result of the PHI.
-Instruction *InstCombiner::FoldPHIArgOpIntoPHI(PHINode &PN) {
- Instruction *FirstInst = cast<Instruction>(PN.getIncomingValue(0));
-
- if (isa<GetElementPtrInst>(FirstInst))
- return FoldPHIArgGEPIntoPHI(PN);
- if (isa<LoadInst>(FirstInst))
- return FoldPHIArgLoadIntoPHI(PN);
-
- // Scan the instruction, looking for input operations that can be folded away.
- // If all input operands to the phi are the same instruction (e.g. a cast from
- // the same type or "+42") we can pull the operation through the PHI, reducing
- // code size and simplifying code.
- Constant *ConstantOp = 0;
- const Type *CastSrcTy = 0;
-
- if (isa<CastInst>(FirstInst)) {
- CastSrcTy = FirstInst->getOperand(0)->getType();
-
- // Be careful about transforming integer PHIs. We don't want to pessimize
- // the code by turning an i32 into an i1293.
- if (isa<IntegerType>(PN.getType()) && isa<IntegerType>(CastSrcTy)) {
- if (!ShouldChangeType(PN.getType(), CastSrcTy))
- return 0;
- }
- } else if (isa<BinaryOperator>(FirstInst) || isa<CmpInst>(FirstInst)) {
- // Can fold binop, compare or shift here if the RHS is a constant,
- // otherwise call FoldPHIArgBinOpIntoPHI.
- ConstantOp = dyn_cast<Constant>(FirstInst->getOperand(1));
- if (ConstantOp == 0)
- return FoldPHIArgBinOpIntoPHI(PN);
- } else {
- return 0; // Cannot fold this operation.
- }
-
- // Check to see if all arguments are the same operation.
- for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
- Instruction *I = dyn_cast<Instruction>(PN.getIncomingValue(i));
- if (I == 0 || !I->hasOneUse() || !I->isSameOperationAs(FirstInst))
- return 0;
- if (CastSrcTy) {
- if (I->getOperand(0)->getType() != CastSrcTy)
- return 0; // Cast operation must match.
- } else if (I->getOperand(1) != ConstantOp) {
- return 0;
- }
- }
-
- // Okay, they are all the same operation. Create a new PHI node of the
- // correct type, and PHI together all of the LHS's of the instructions.
- PHINode *NewPN = PHINode::Create(FirstInst->getOperand(0)->getType(),
- PN.getName()+".in");
- NewPN->reserveOperandSpace(PN.getNumOperands()/2);
-
- Value *InVal = FirstInst->getOperand(0);
- NewPN->addIncoming(InVal, PN.getIncomingBlock(0));
-
- // Add all operands to the new PHI.
- for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
- Value *NewInVal = cast<Instruction>(PN.getIncomingValue(i))->getOperand(0);
- if (NewInVal != InVal)
- InVal = 0;
- NewPN->addIncoming(NewInVal, PN.getIncomingBlock(i));
- }
-
- Value *PhiVal;
- if (InVal) {
- // The new PHI unions all of the same values together. This is really
- // common, so we handle it intelligently here for compile-time speed.
- PhiVal = InVal;
- delete NewPN;
- } else {
- InsertNewInstBefore(NewPN, PN);
- PhiVal = NewPN;
- }
-
- // Insert and return the new operation.
- if (CastInst *FirstCI = dyn_cast<CastInst>(FirstInst))
- return CastInst::Create(FirstCI->getOpcode(), PhiVal, PN.getType());
-
- if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(FirstInst))
- return BinaryOperator::Create(BinOp->getOpcode(), PhiVal, ConstantOp);
-
- CmpInst *CIOp = cast<CmpInst>(FirstInst);
- return CmpInst::Create(CIOp->getOpcode(), CIOp->getPredicate(),
- PhiVal, ConstantOp);
-}
-
-/// DeadPHICycle - Return true if this PHI node is only used by a PHI node cycle
-/// that is dead.
-static bool DeadPHICycle(PHINode *PN,
- SmallPtrSet<PHINode*, 16> &PotentiallyDeadPHIs) {
- if (PN->use_empty()) return true;
- if (!PN->hasOneUse()) return false;
-
- // Remember this node, and if we find the cycle, return.
- if (!PotentiallyDeadPHIs.insert(PN))
- return true;
-
- // Don't scan crazily complex things.
- if (PotentiallyDeadPHIs.size() == 16)
- return false;
-
- if (PHINode *PU = dyn_cast<PHINode>(PN->use_back()))
- return DeadPHICycle(PU, PotentiallyDeadPHIs);
-
- return false;
-}
-
-/// PHIsEqualValue - Return true if this phi node is always equal to
-/// NonPhiInVal. This happens with mutually cyclic phi nodes like:
-/// z = some value; x = phi (y, z); y = phi (x, z)
-static bool PHIsEqualValue(PHINode *PN, Value *NonPhiInVal,
- SmallPtrSet<PHINode*, 16> &ValueEqualPHIs) {
- // See if we already saw this PHI node.
- if (!ValueEqualPHIs.insert(PN))
- return true;
-
- // Don't scan crazily complex things.
- if (ValueEqualPHIs.size() == 16)
- return false;
-
- // Scan the operands to see if they are either phi nodes or are equal to
- // the value.
- for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
- Value *Op = PN->getIncomingValue(i);
- if (PHINode *OpPN = dyn_cast<PHINode>(Op)) {
- if (!PHIsEqualValue(OpPN, NonPhiInVal, ValueEqualPHIs))
- return false;
- } else if (Op != NonPhiInVal)
- return false;
- }
-
- return true;
-}
-
-
-namespace {
-struct PHIUsageRecord {
- unsigned PHIId; // The ID # of the PHI (something determinstic to sort on)
- unsigned Shift; // The amount shifted.
- Instruction *Inst; // The trunc instruction.
-
- PHIUsageRecord(unsigned pn, unsigned Sh, Instruction *User)
- : PHIId(pn), Shift(Sh), Inst(User) {}
-
- bool operator<(const PHIUsageRecord &RHS) const {
- if (PHIId < RHS.PHIId) return true;
- if (PHIId > RHS.PHIId) return false;
- if (Shift < RHS.Shift) return true;
- if (Shift > RHS.Shift) return false;
- return Inst->getType()->getPrimitiveSizeInBits() <
- RHS.Inst->getType()->getPrimitiveSizeInBits();
- }
-};
-
-struct LoweredPHIRecord {
- PHINode *PN; // The PHI that was lowered.
- unsigned Shift; // The amount shifted.
- unsigned Width; // The width extracted.
-
- LoweredPHIRecord(PHINode *pn, unsigned Sh, const Type *Ty)
- : PN(pn), Shift(Sh), Width(Ty->getPrimitiveSizeInBits()) {}
-
- // Ctor form used by DenseMap.
- LoweredPHIRecord(PHINode *pn, unsigned Sh)
- : PN(pn), Shift(Sh), Width(0) {}
-};
-}
-
-namespace llvm {
- template<>
- struct DenseMapInfo<LoweredPHIRecord> {
- static inline LoweredPHIRecord getEmptyKey() {
- return LoweredPHIRecord(0, 0);
- }
- static inline LoweredPHIRecord getTombstoneKey() {
- return LoweredPHIRecord(0, 1);
- }
- static unsigned getHashValue(const LoweredPHIRecord &Val) {
- return DenseMapInfo<PHINode*>::getHashValue(Val.PN) ^ (Val.Shift>>3) ^
- (Val.Width>>3);
- }
- static bool isEqual(const LoweredPHIRecord &LHS,
- const LoweredPHIRecord &RHS) {
- return LHS.PN == RHS.PN && LHS.Shift == RHS.Shift &&
- LHS.Width == RHS.Width;
- }
- };
- template <>
- struct isPodLike<LoweredPHIRecord> { static const bool value = true; };
-}
-
-
-/// SliceUpIllegalIntegerPHI - This is an integer PHI and we know that it has an
-/// illegal type: see if it is only used by trunc or trunc(lshr) operations. If
-/// so, we split the PHI into the various pieces being extracted. This sort of
-/// thing is introduced when SROA promotes an aggregate to large integer values.
-///
-/// TODO: The user of the trunc may be an bitcast to float/double/vector or an
-/// inttoptr. We should produce new PHIs in the right type.
-///
-Instruction *InstCombiner::SliceUpIllegalIntegerPHI(PHINode &FirstPhi) {
- // PHIUsers - Keep track of all of the truncated values extracted from a set
- // of PHIs, along with their offset. These are the things we want to rewrite.
- SmallVector<PHIUsageRecord, 16> PHIUsers;
-
- // PHIs are often mutually cyclic, so we keep track of a whole set of PHI
- // nodes which are extracted from. PHIsToSlice is a set we use to avoid
- // revisiting PHIs, PHIsInspected is a ordered list of PHIs that we need to
- // check the uses of (to ensure they are all extracts).
- SmallVector<PHINode*, 8> PHIsToSlice;
- SmallPtrSet<PHINode*, 8> PHIsInspected;
-
- PHIsToSlice.push_back(&FirstPhi);
- PHIsInspected.insert(&FirstPhi);
-
- for (unsigned PHIId = 0; PHIId != PHIsToSlice.size(); ++PHIId) {
- PHINode *PN = PHIsToSlice[PHIId];
-
- // Scan the input list of the PHI. If any input is an invoke, and if the
- // input is defined in the predecessor, then we won't be split the critical
- // edge which is required to insert a truncate. Because of this, we have to
- // bail out.
- for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
- InvokeInst *II = dyn_cast<InvokeInst>(PN->getIncomingValue(i));
- if (II == 0) continue;
- if (II->getParent() != PN->getIncomingBlock(i))
- continue;
-
- // If we have a phi, and if it's directly in the predecessor, then we have
- // a critical edge where we need to put the truncate. Since we can't
- // split the edge in instcombine, we have to bail out.
- return 0;
- }
-
-
- for (Value::use_iterator UI = PN->use_begin(), E = PN->use_end();
- UI != E; ++UI) {
- Instruction *User = cast<Instruction>(*UI);
-
- // If the user is a PHI, inspect its uses recursively.
- if (PHINode *UserPN = dyn_cast<PHINode>(User)) {
- if (PHIsInspected.insert(UserPN))
- PHIsToSlice.push_back(UserPN);
- continue;
- }
-
- // Truncates are always ok.
- if (isa<TruncInst>(User)) {
- PHIUsers.push_back(PHIUsageRecord(PHIId, 0, User));
- continue;
- }
-
- // Otherwise it must be a lshr which can only be used by one trunc.
- if (User->getOpcode() != Instruction::LShr ||
- !User->hasOneUse() || !isa<TruncInst>(User->use_back()) ||
- !isa<ConstantInt>(User->getOperand(1)))
- return 0;
-
- unsigned Shift = cast<ConstantInt>(User->getOperand(1))->getZExtValue();
- PHIUsers.push_back(PHIUsageRecord(PHIId, Shift, User->use_back()));
- }
- }
-
- // If we have no users, they must be all self uses, just nuke the PHI.
- if (PHIUsers.empty())
- return ReplaceInstUsesWith(FirstPhi, UndefValue::get(FirstPhi.getType()));
-
- // If this phi node is transformable, create new PHIs for all the pieces
- // extracted out of it. First, sort the users by their offset and size.
- array_pod_sort(PHIUsers.begin(), PHIUsers.end());
-
- DEBUG(errs() << "SLICING UP PHI: " << FirstPhi << '\n';
- for (unsigned i = 1, e = PHIsToSlice.size(); i != e; ++i)
- errs() << "AND USER PHI #" << i << ": " << *PHIsToSlice[i] <<'\n';
- );
-
- // PredValues - This is a temporary used when rewriting PHI nodes. It is
- // hoisted out here to avoid construction/destruction thrashing.
- DenseMap<BasicBlock*, Value*> PredValues;
-
- // ExtractedVals - Each new PHI we introduce is saved here so we don't
- // introduce redundant PHIs.
- DenseMap<LoweredPHIRecord, PHINode*> ExtractedVals;
-
- for (unsigned UserI = 0, UserE = PHIUsers.size(); UserI != UserE; ++UserI) {
- unsigned PHIId = PHIUsers[UserI].PHIId;
- PHINode *PN = PHIsToSlice[PHIId];
- unsigned Offset = PHIUsers[UserI].Shift;
- const Type *Ty = PHIUsers[UserI].Inst->getType();
-
- PHINode *EltPHI;
-
- // If we've already lowered a user like this, reuse the previously lowered
- // value.
- if ((EltPHI = ExtractedVals[LoweredPHIRecord(PN, Offset, Ty)]) == 0) {
-
- // Otherwise, Create the new PHI node for this user.
- EltPHI = PHINode::Create(Ty, PN->getName()+".off"+Twine(Offset), PN);
- assert(EltPHI->getType() != PN->getType() &&
- "Truncate didn't shrink phi?");
-
- for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
- BasicBlock *Pred = PN->getIncomingBlock(i);
- Value *&PredVal = PredValues[Pred];
-
- // If we already have a value for this predecessor, reuse it.
- if (PredVal) {
- EltPHI->addIncoming(PredVal, Pred);
- continue;
- }
-
- // Handle the PHI self-reuse case.
- Value *InVal = PN->getIncomingValue(i);
- if (InVal == PN) {
- PredVal = EltPHI;
- EltPHI->addIncoming(PredVal, Pred);
- continue;
- }
-
- if (PHINode *InPHI = dyn_cast<PHINode>(PN)) {
- // If the incoming value was a PHI, and if it was one of the PHIs we
- // already rewrote it, just use the lowered value.
- if (Value *Res = ExtractedVals[LoweredPHIRecord(InPHI, Offset, Ty)]) {
- PredVal = Res;
- EltPHI->addIncoming(PredVal, Pred);
- continue;
- }
- }
-
- // Otherwise, do an extract in the predecessor.
- Builder->SetInsertPoint(Pred, Pred->getTerminator());
- Value *Res = InVal;
- if (Offset)
- Res = Builder->CreateLShr(Res, ConstantInt::get(InVal->getType(),
- Offset), "extract");
- Res = Builder->CreateTrunc(Res, Ty, "extract.t");
- PredVal = Res;
- EltPHI->addIncoming(Res, Pred);
-
- // If the incoming value was a PHI, and if it was one of the PHIs we are
- // rewriting, we will ultimately delete the code we inserted. This
- // means we need to revisit that PHI to make sure we extract out the
- // needed piece.
- if (PHINode *OldInVal = dyn_cast<PHINode>(PN->getIncomingValue(i)))
- if (PHIsInspected.count(OldInVal)) {
- unsigned RefPHIId = std::find(PHIsToSlice.begin(),PHIsToSlice.end(),
- OldInVal)-PHIsToSlice.begin();
- PHIUsers.push_back(PHIUsageRecord(RefPHIId, Offset,
- cast<Instruction>(Res)));
- ++UserE;
- }
- }
- PredValues.clear();
-
- DEBUG(errs() << " Made element PHI for offset " << Offset << ": "
- << *EltPHI << '\n');
- ExtractedVals[LoweredPHIRecord(PN, Offset, Ty)] = EltPHI;
- }
-
- // Replace the use of this piece with the PHI node.
- ReplaceInstUsesWith(*PHIUsers[UserI].Inst, EltPHI);
- }
-
- // Replace all the remaining uses of the PHI nodes (self uses and the lshrs)
- // with undefs.
- Value *Undef = UndefValue::get(FirstPhi.getType());
- for (unsigned i = 1, e = PHIsToSlice.size(); i != e; ++i)
- ReplaceInstUsesWith(*PHIsToSlice[i], Undef);
- return ReplaceInstUsesWith(FirstPhi, Undef);
-}
-
-// PHINode simplification
-//
-Instruction *InstCombiner::visitPHINode(PHINode &PN) {
- // If LCSSA is around, don't mess with Phi nodes
- if (MustPreserveLCSSA) return 0;
-
- if (Value *V = PN.hasConstantValue())
- return ReplaceInstUsesWith(PN, V);
-
- // If all PHI operands are the same operation, pull them through the PHI,
- // reducing code size.
- if (isa<Instruction>(PN.getIncomingValue(0)) &&
- isa<Instruction>(PN.getIncomingValue(1)) &&
- cast<Instruction>(PN.getIncomingValue(0))->getOpcode() ==
- cast<Instruction>(PN.getIncomingValue(1))->getOpcode() &&
- // FIXME: The hasOneUse check will fail for PHIs that use the value more
- // than themselves more than once.
- PN.getIncomingValue(0)->hasOneUse())
- if (Instruction *Result = FoldPHIArgOpIntoPHI(PN))
- return Result;
-
- // If this is a trivial cycle in the PHI node graph, remove it. Basically, if
- // this PHI only has a single use (a PHI), and if that PHI only has one use (a
- // PHI)... break the cycle.
- if (PN.hasOneUse()) {
- Instruction *PHIUser = cast<Instruction>(PN.use_back());
- if (PHINode *PU = dyn_cast<PHINode>(PHIUser)) {
- SmallPtrSet<PHINode*, 16> PotentiallyDeadPHIs;
- PotentiallyDeadPHIs.insert(&PN);
- if (DeadPHICycle(PU, PotentiallyDeadPHIs))
- return ReplaceInstUsesWith(PN, UndefValue::get(PN.getType()));
- }
-
- // If this phi has a single use, and if that use just computes a value for
- // the next iteration of a loop, delete the phi. This occurs with unused
- // induction variables, e.g. "for (int j = 0; ; ++j);". Detecting this
- // common case here is good because the only other things that catch this
- // are induction variable analysis (sometimes) and ADCE, which is only run
- // late.
- if (PHIUser->hasOneUse() &&
- (isa<BinaryOperator>(PHIUser) || isa<GetElementPtrInst>(PHIUser)) &&
- PHIUser->use_back() == &PN) {
- return ReplaceInstUsesWith(PN, UndefValue::get(PN.getType()));
- }
- }
-
- // We sometimes end up with phi cycles that non-obviously end up being the
- // same value, for example:
- // z = some value; x = phi (y, z); y = phi (x, z)
- // where the phi nodes don't necessarily need to be in the same block. Do a
- // quick check to see if the PHI node only contains a single non-phi value, if
- // so, scan to see if the phi cycle is actually equal to that value.
- {
- unsigned InValNo = 0, NumOperandVals = PN.getNumIncomingValues();
- // Scan for the first non-phi operand.
- while (InValNo != NumOperandVals &&
- isa<PHINode>(PN.getIncomingValue(InValNo)))
- ++InValNo;
-
- if (InValNo != NumOperandVals) {
- Value *NonPhiInVal = PN.getOperand(InValNo);
-
- // Scan the rest of the operands to see if there are any conflicts, if so
- // there is no need to recursively scan other phis.
- for (++InValNo; InValNo != NumOperandVals; ++InValNo) {
- Value *OpVal = PN.getIncomingValue(InValNo);
- if (OpVal != NonPhiInVal && !isa<PHINode>(OpVal))
- break;
- }
-
- // If we scanned over all operands, then we have one unique value plus
- // phi values. Scan PHI nodes to see if they all merge in each other or
- // the value.
- if (InValNo == NumOperandVals) {
- SmallPtrSet<PHINode*, 16> ValueEqualPHIs;
- if (PHIsEqualValue(&PN, NonPhiInVal, ValueEqualPHIs))
- return ReplaceInstUsesWith(PN, NonPhiInVal);
- }
- }
- }
-
- // If there are multiple PHIs, sort their operands so that they all list
- // the blocks in the same order. This will help identical PHIs be eliminated
- // by other passes. Other passes shouldn't depend on this for correctness
- // however.
- PHINode *FirstPN = cast<PHINode>(PN.getParent()->begin());
- if (&PN != FirstPN)
- for (unsigned i = 0, e = FirstPN->getNumIncomingValues(); i != e; ++i) {
- BasicBlock *BBA = PN.getIncomingBlock(i);
- BasicBlock *BBB = FirstPN->getIncomingBlock(i);
- if (BBA != BBB) {
- Value *VA = PN.getIncomingValue(i);
- unsigned j = PN.getBasicBlockIndex(BBB);
- Value *VB = PN.getIncomingValue(j);
- PN.setIncomingBlock(i, BBB);
- PN.setIncomingValue(i, VB);
- PN.setIncomingBlock(j, BBA);
- PN.setIncomingValue(j, VA);
- // NOTE: Instcombine normally would want us to "return &PN" if we
- // modified any of the operands of an instruction. However, since we
- // aren't adding or removing uses (just rearranging them) we don't do
- // this in this case.
- }
- }
-
- // If this is an integer PHI and we know that it has an illegal type, see if
- // it is only used by trunc or trunc(lshr) operations. If so, we split the
- // PHI into the various pieces being extracted. This sort of thing is
- // introduced when SROA promotes an aggregate to a single large integer type.
- if (isa<IntegerType>(PN.getType()) && TD &&
- !TD->isLegalInteger(PN.getType()->getPrimitiveSizeInBits()))
- if (Instruction *Res = SliceUpIllegalIntegerPHI(PN))
- return Res;
-
- return 0;
-}
-
-Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
- SmallVector<Value*, 8> Ops(GEP.op_begin(), GEP.op_end());
-
- if (Value *V = SimplifyGEPInst(&Ops[0], Ops.size(), TD))
- return ReplaceInstUsesWith(GEP, V);
-
- Value *PtrOp = GEP.getOperand(0);
-
- if (isa<UndefValue>(GEP.getOperand(0)))
- return ReplaceInstUsesWith(GEP, UndefValue::get(GEP.getType()));
-
- // Eliminate unneeded casts for indices.
- if (TD) {
- bool MadeChange = false;
- unsigned PtrSize = TD->getPointerSizeInBits();
-
- gep_type_iterator GTI = gep_type_begin(GEP);
- for (User::op_iterator I = GEP.op_begin() + 1, E = GEP.op_end();
- I != E; ++I, ++GTI) {
- if (!isa<SequentialType>(*GTI)) continue;
-
- // If we are using a wider index than needed for this platform, shrink it
- // to what we need. If narrower, sign-extend it to what we need. This
- // explicit cast can make subsequent optimizations more obvious.
- unsigned OpBits = cast<IntegerType>((*I)->getType())->getBitWidth();
- if (OpBits == PtrSize)
- continue;
-
- *I = Builder->CreateIntCast(*I, TD->getIntPtrType(GEP.getContext()),true);
- MadeChange = true;
- }
- if (MadeChange) return &GEP;
- }
-
- // Combine Indices - If the source pointer to this getelementptr instruction
- // is a getelementptr instruction, combine the indices of the two
- // getelementptr instructions into a single instruction.
- //
- if (GEPOperator *Src = dyn_cast<GEPOperator>(PtrOp)) {
- // Note that if our source is a gep chain itself that we wait for that
- // chain to be resolved before we perform this transformation. This
- // avoids us creating a TON of code in some cases.
- //
- if (GetElementPtrInst *SrcGEP =
- dyn_cast<GetElementPtrInst>(Src->getOperand(0)))
- if (SrcGEP->getNumOperands() == 2)
- return 0; // Wait until our source is folded to completion.
-
- SmallVector<Value*, 8> Indices;
-
- // Find out whether the last index in the source GEP is a sequential idx.
- bool EndsWithSequential = false;
- for (gep_type_iterator I = gep_type_begin(*Src), E = gep_type_end(*Src);
- I != E; ++I)
- EndsWithSequential = !isa<StructType>(*I);
-
- // Can we combine the two pointer arithmetics offsets?
- if (EndsWithSequential) {
- // Replace: gep (gep %P, long B), long A, ...
- // With: T = long A+B; gep %P, T, ...
- //
- Value *Sum;
- Value *SO1 = Src->getOperand(Src->getNumOperands()-1);
- Value *GO1 = GEP.getOperand(1);
- if (SO1 == Constant::getNullValue(SO1->getType())) {
- Sum = GO1;
- } else if (GO1 == Constant::getNullValue(GO1->getType())) {
- Sum = SO1;
- } else {
- // If they aren't the same type, then the input hasn't been processed
- // by the loop above yet (which canonicalizes sequential index types to
- // intptr_t). Just avoid transforming this until the input has been
- // normalized.
- if (SO1->getType() != GO1->getType())
- return 0;
- Sum = Builder->CreateAdd(SO1, GO1, PtrOp->getName()+".sum");
- }
-
- // Update the GEP in place if possible.
- if (Src->getNumOperands() == 2) {
- GEP.setOperand(0, Src->getOperand(0));
- GEP.setOperand(1, Sum);
- return &GEP;
- }
- Indices.append(Src->op_begin()+1, Src->op_end()-1);
- Indices.push_back(Sum);
- Indices.append(GEP.op_begin()+2, GEP.op_end());
- } else if (isa<Constant>(*GEP.idx_begin()) &&
- cast<Constant>(*GEP.idx_begin())->isNullValue() &&
- Src->getNumOperands() != 1) {
- // Otherwise we can do the fold if the first index of the GEP is a zero
- Indices.append(Src->op_begin()+1, Src->op_end());
- Indices.append(GEP.idx_begin()+1, GEP.idx_end());
- }
-
- if (!Indices.empty())
- return (cast<GEPOperator>(&GEP)->isInBounds() &&
- Src->isInBounds()) ?
- GetElementPtrInst::CreateInBounds(Src->getOperand(0), Indices.begin(),
- Indices.end(), GEP.getName()) :
- GetElementPtrInst::Create(Src->getOperand(0), Indices.begin(),
- Indices.end(), GEP.getName());
- }
-
- // Handle gep(bitcast x) and gep(gep x, 0, 0, 0).
- if (Value *X = getBitCastOperand(PtrOp)) {
- assert(isa<PointerType>(X->getType()) && "Must be cast from pointer");
-
- // If the input bitcast is actually "bitcast(bitcast(x))", then we don't
- // want to change the gep until the bitcasts are eliminated.
- if (getBitCastOperand(X)) {
- Worklist.AddValue(PtrOp);
- return 0;
- }
-
bool HasZeroPointerIndex = false;
if (ConstantInt *C = dyn_cast<ConstantInt>(GEP.getOperand(1)))
HasZeroPointerIndex = C->isZero();
// This occurs when the program declares an array extern like "int X[];"
if (HasZeroPointerIndex) {
const PointerType *CPTy = cast<PointerType>(PtrOp->getType());
- const PointerType *XTy = cast<PointerType>(X->getType());
if (const ArrayType *CATy =
dyn_cast<ArrayType>(CPTy->getElementType())) {
// GEP (bitcast i8* X to [0 x i8]*), i32 0, ... ?
- if (CATy->getElementType() == XTy->getElementType()) {
+ if (CATy->getElementType() == StrippedPtrTy->getElementType()) {
// -> GEP i8* X, ...
- SmallVector<Value*, 8> Indices(GEP.idx_begin()+1, GEP.idx_end());
- return cast<GEPOperator>(&GEP)->isInBounds() ?
- GetElementPtrInst::CreateInBounds(X, Indices.begin(), Indices.end(),
- GEP.getName()) :
- GetElementPtrInst::Create(X, Indices.begin(), Indices.end(),
- GEP.getName());
+ SmallVector<Value*, 8> Idx(GEP.idx_begin()+1, GEP.idx_end());
+ GetElementPtrInst *Res =
+ GetElementPtrInst::Create(StrippedPtr, Idx.begin(),
+ Idx.end(), GEP.getName());
+ Res->setIsInBounds(GEP.isInBounds());
+ return Res;
}
- if (const ArrayType *XATy = dyn_cast<ArrayType>(XTy->getElementType())){
+ if (const ArrayType *XATy =
+ dyn_cast<ArrayType>(StrippedPtrTy->getElementType())){
// GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ... ?
if (CATy->getElementType() == XATy->getElementType()) {
// -> GEP [10 x i8]* X, i32 0, ...
// to an array of the same type as the destination pointer
// array. Because the array type is never stepped over (there
// is a leading zero) we can fold the cast into this GEP.
- GEP.setOperand(0, X);
+ GEP.setOperand(0, StrippedPtr);
return &GEP;
}
}
// Transform things like:
// %t = getelementptr i32* bitcast ([2 x i32]* %str to i32*), i32 %V
// into: %t1 = getelementptr [2 x i32]* %str, i32 0, i32 %V; bitcast
- const Type *SrcElTy = cast<PointerType>(X->getType())->getElementType();
+ const Type *SrcElTy = StrippedPtrTy->getElementType();
const Type *ResElTy=cast<PointerType>(PtrOp->getType())->getElementType();
if (TD && isa<ArrayType>(SrcElTy) &&
TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType()) ==
Value *Idx[2];
Idx[0] = Constant::getNullValue(Type::getInt32Ty(GEP.getContext()));
Idx[1] = GEP.getOperand(1);
- Value *NewGEP = cast<GEPOperator>(&GEP)->isInBounds() ?
- Builder->CreateInBoundsGEP(X, Idx, Idx + 2, GEP.getName()) :
- Builder->CreateGEP(X, Idx, Idx + 2, GEP.getName());
+ Value *NewGEP = GEP.isInBounds() ?
+ Builder->CreateInBoundsGEP(StrippedPtr, Idx, Idx + 2, GEP.getName()) :
+ Builder->CreateGEP(StrippedPtr, Idx, Idx + 2, GEP.getName());
// V and GEP are both pointer types --> BitCast
return new BitCastInst(NewGEP, GEP.getType());
}
// (where tmp = 8*tmp2) into:
// getelementptr [100 x double]* %arr, i32 0, i32 %tmp2; bitcast
- if (TD && isa<ArrayType>(SrcElTy) &&
- ResElTy == Type::getInt8Ty(GEP.getContext())) {
+ if (TD && isa<ArrayType>(SrcElTy) && ResElTy->isIntegerTy(8)) {
uint64_t ArrayEltSize =
TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType());
Value *Idx[2];
Idx[0] = Constant::getNullValue(Type::getInt32Ty(GEP.getContext()));
Idx[1] = NewIdx;
- Value *NewGEP = cast<GEPOperator>(&GEP)->isInBounds() ?
- Builder->CreateInBoundsGEP(X, Idx, Idx + 2, GEP.getName()) :
- Builder->CreateGEP(X, Idx, Idx + 2, GEP.getName());
+ Value *NewGEP = GEP.isInBounds() ?
+ Builder->CreateInBoundsGEP(StrippedPtr, Idx, Idx + 2,GEP.getName()):
+ Builder->CreateGEP(StrippedPtr, Idx, Idx + 2, GEP.getName());
// The NewGEP must be pointer typed, so must the old one -> BitCast
return new BitCastInst(NewGEP, GEP.getType());
}
return new BitCastInst(BCI->getOperand(0), GEP.getType());
}
- // Otherwise, if the offset is non-zero, we need to find out if there is a
- // field at Offset in 'A's type. If so, we can pull the cast through the
- // GEP.
- SmallVector<Value*, 8> NewIndices;
- const Type *InTy =
- cast<PointerType>(BCI->getOperand(0)->getType())->getElementType();
- if (FindElementAtOffset(InTy, Offset, NewIndices)) {
- Value *NGEP = cast<GEPOperator>(&GEP)->isInBounds() ?
- Builder->CreateInBoundsGEP(BCI->getOperand(0), NewIndices.begin(),
- NewIndices.end()) :
- Builder->CreateGEP(BCI->getOperand(0), NewIndices.begin(),
- NewIndices.end());
-
- if (NGEP->getType() == GEP.getType())
- return ReplaceInstUsesWith(GEP, NGEP);
- NGEP->takeName(&GEP);
- return new BitCastInst(NGEP, GEP.getType());
- }
- }
- }
-
- return 0;
-}
-
-Instruction *InstCombiner::visitAllocaInst(AllocaInst &AI) {
- // Convert: alloca Ty, C - where C is a constant != 1 into: alloca [C x Ty], 1
- if (AI.isArrayAllocation()) { // Check C != 1
- if (const ConstantInt *C = dyn_cast<ConstantInt>(AI.getArraySize())) {
- const Type *NewTy =
- ArrayType::get(AI.getAllocatedType(), C->getZExtValue());
- assert(isa<AllocaInst>(AI) && "Unknown type of allocation inst!");
- AllocaInst *New = Builder->CreateAlloca(NewTy, 0, AI.getName());
- New->setAlignment(AI.getAlignment());
-
- // Scan to the end of the allocation instructions, to skip over a block of
- // allocas if possible...also skip interleaved debug info
- //
- BasicBlock::iterator It = New;
- while (isa<AllocaInst>(*It) || isa<DbgInfoIntrinsic>(*It)) ++It;
-
- // Now that I is pointing to the first non-allocation-inst in the block,
- // insert our getelementptr instruction...
- //
- Value *NullIdx =Constant::getNullValue(Type::getInt32Ty(AI.getContext()));
- Value *Idx[2];
- Idx[0] = NullIdx;
- Idx[1] = NullIdx;
- Value *V = GetElementPtrInst::CreateInBounds(New, Idx, Idx + 2,
- New->getName()+".sub", It);
-
- // Now make everything use the getelementptr instead of the original
- // allocation.
- return ReplaceInstUsesWith(AI, V);
- } else if (isa<UndefValue>(AI.getArraySize())) {
- return ReplaceInstUsesWith(AI, Constant::getNullValue(AI.getType()));
- }
- }
-
- if (TD && isa<AllocaInst>(AI) && AI.getAllocatedType()->isSized()) {
- // If alloca'ing a zero byte object, replace the alloca with a null pointer.
- // Note that we only do this for alloca's, because malloc should allocate
- // and return a unique pointer, even for a zero byte allocation.
- if (TD->getTypeAllocSize(AI.getAllocatedType()) == 0)
- return ReplaceInstUsesWith(AI, Constant::getNullValue(AI.getType()));
-
- // If the alignment is 0 (unspecified), assign it the preferred alignment.
- if (AI.getAlignment() == 0)
- AI.setAlignment(TD->getPrefTypeAlignment(AI.getAllocatedType()));
- }
-
- return 0;
-}
-
-Instruction *InstCombiner::visitFree(Instruction &FI) {
- Value *Op = FI.getOperand(1);
-
- // free undef -> unreachable.
- if (isa<UndefValue>(Op)) {
- // Insert a new store to null because we cannot modify the CFG here.
- new StoreInst(ConstantInt::getTrue(FI.getContext()),
- UndefValue::get(Type::getInt1PtrTy(FI.getContext())), &FI);
- return EraseInstFromFunction(FI);
- }
-
- // If we have 'free null' delete the instruction. This can happen in stl code
- // when lots of inlining happens.
- if (isa<ConstantPointerNull>(Op))
- return EraseInstFromFunction(FI);
-
- // If we have a malloc call whose only use is a free call, delete both.
- if (isMalloc(Op)) {
- if (CallInst* CI = extractMallocCallFromBitCast(Op)) {
- if (Op->hasOneUse() && CI->hasOneUse()) {
- EraseInstFromFunction(FI);
- EraseInstFromFunction(*CI);
- return EraseInstFromFunction(*cast<Instruction>(Op));
- }
- } else {
- // Op is a call to malloc
- if (Op->hasOneUse()) {
- EraseInstFromFunction(FI);
- return EraseInstFromFunction(*cast<Instruction>(Op));
- }
- }
- }
-
- return 0;
-}
-
-/// InstCombineLoadCast - Fold 'load (cast P)' -> cast (load P)' when possible.
-static Instruction *InstCombineLoadCast(InstCombiner &IC, LoadInst &LI,
- const TargetData *TD) {
- User *CI = cast<User>(LI.getOperand(0));
- Value *CastOp = CI->getOperand(0);
-
- const PointerType *DestTy = cast<PointerType>(CI->getType());
- const Type *DestPTy = DestTy->getElementType();
- if (const PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType())) {
-
- // If the address spaces don't match, don't eliminate the cast.
- if (DestTy->getAddressSpace() != SrcTy->getAddressSpace())
- return 0;
-
- const Type *SrcPTy = SrcTy->getElementType();
-
- if (DestPTy->isInteger() || isa<PointerType>(DestPTy) ||
- isa<VectorType>(DestPTy)) {
- // If the source is an array, the code below will not succeed. Check to
- // see if a trivial 'gep P, 0, 0' will help matters. Only do this for
- // constants.
- if (const ArrayType *ASrcTy = dyn_cast<ArrayType>(SrcPTy))
- if (Constant *CSrc = dyn_cast<Constant>(CastOp))
- if (ASrcTy->getNumElements() != 0) {
- Value *Idxs[2];
- Idxs[0] = Constant::getNullValue(Type::getInt32Ty(LI.getContext()));
- Idxs[1] = Idxs[0];
- CastOp = ConstantExpr::getGetElementPtr(CSrc, Idxs, 2);
- SrcTy = cast<PointerType>(CastOp->getType());
- SrcPTy = SrcTy->getElementType();
- }
-
- if (IC.getTargetData() &&
- (SrcPTy->isInteger() || isa<PointerType>(SrcPTy) ||
- isa<VectorType>(SrcPTy)) &&
- // Do not allow turning this into a load of an integer, which is then
- // casted to a pointer, this pessimizes pointer analysis a lot.
- (isa<PointerType>(SrcPTy) == isa<PointerType>(LI.getType())) &&
- IC.getTargetData()->getTypeSizeInBits(SrcPTy) ==
- IC.getTargetData()->getTypeSizeInBits(DestPTy)) {
-
- // Okay, we are casting from one integer or pointer type to another of
- // the same size. Instead of casting the pointer before the load, cast
- // the result of the loaded value.
- Value *NewLoad =
- IC.Builder->CreateLoad(CastOp, LI.isVolatile(), CI->getName());
- // Now cast the result of the load.
- return new BitCastInst(NewLoad, LI.getType());
- }
- }
- }
- return 0;
-}
-
-Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
- Value *Op = LI.getOperand(0);
-
- // Attempt to improve the alignment.
- if (TD) {
- unsigned KnownAlign =
- GetOrEnforceKnownAlignment(Op, TD->getPrefTypeAlignment(LI.getType()));
- if (KnownAlign >
- (LI.getAlignment() == 0 ? TD->getABITypeAlignment(LI.getType()) :
- LI.getAlignment()))
- LI.setAlignment(KnownAlign);
- }
-
- // load (cast X) --> cast (load X) iff safe.
- if (isa<CastInst>(Op))
- if (Instruction *Res = InstCombineLoadCast(*this, LI, TD))
- return Res;
-
- // None of the following transforms are legal for volatile loads.
- if (LI.isVolatile()) return 0;
-
- // Do really simple store-to-load forwarding and load CSE, to catch cases
- // where there are several consequtive memory accesses to the same location,
- // separated by a few arithmetic operations.
- BasicBlock::iterator BBI = &LI;
- if (Value *AvailableVal = FindAvailableLoadedValue(Op, LI.getParent(), BBI,6))
- return ReplaceInstUsesWith(LI, AvailableVal);
-
- // load(gep null, ...) -> unreachable
- if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(Op)) {
- const Value *GEPI0 = GEPI->getOperand(0);
- // TODO: Consider a target hook for valid address spaces for this xform.
- if (isa<ConstantPointerNull>(GEPI0) && GEPI->getPointerAddressSpace() == 0){
- // Insert a new store to null instruction before the load to indicate
- // that this code is not reachable. We do this instead of inserting
- // an unreachable instruction directly because we cannot modify the
- // CFG.
- new StoreInst(UndefValue::get(LI.getType()),
- Constant::getNullValue(Op->getType()), &LI);
- return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType()));
- }
- }
-
- // load null/undef -> unreachable
- // TODO: Consider a target hook for valid address spaces for this xform.
- if (isa<UndefValue>(Op) ||
- (isa<ConstantPointerNull>(Op) && LI.getPointerAddressSpace() == 0)) {
- // Insert a new store to null instruction before the load to indicate that
- // this code is not reachable. We do this instead of inserting an
- // unreachable instruction directly because we cannot modify the CFG.
- new StoreInst(UndefValue::get(LI.getType()),
- Constant::getNullValue(Op->getType()), &LI);
- return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType()));
- }
-
- // Instcombine load (constantexpr_cast global) -> cast (load global)
- if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Op))
- if (CE->isCast())
- if (Instruction *Res = InstCombineLoadCast(*this, LI, TD))
- return Res;
-
- if (Op->hasOneUse()) {
- // Change select and PHI nodes to select values instead of addresses: this
- // helps alias analysis out a lot, allows many others simplifications, and
- // exposes redundancy in the code.
- //
- // Note that we cannot do the transformation unless we know that the
- // introduced loads cannot trap! Something like this is valid as long as
- // the condition is always false: load (select bool %C, int* null, int* %G),
- // but it would not be valid if we transformed it to load from null
- // unconditionally.
- //
- if (SelectInst *SI = dyn_cast<SelectInst>(Op)) {
- // load (select (Cond, &V1, &V2)) --> select(Cond, load &V1, load &V2).
- if (isSafeToLoadUnconditionally(SI->getOperand(1), SI) &&
- isSafeToLoadUnconditionally(SI->getOperand(2), SI)) {
- Value *V1 = Builder->CreateLoad(SI->getOperand(1),
- SI->getOperand(1)->getName()+".val");
- Value *V2 = Builder->CreateLoad(SI->getOperand(2),
- SI->getOperand(2)->getName()+".val");
- return SelectInst::Create(SI->getCondition(), V1, V2);
- }
-
- // load (select (cond, null, P)) -> load P
- if (Constant *C = dyn_cast<Constant>(SI->getOperand(1)))
- if (C->isNullValue()) {
- LI.setOperand(0, SI->getOperand(2));
- return &LI;
- }
-
- // load (select (cond, P, null)) -> load P
- if (Constant *C = dyn_cast<Constant>(SI->getOperand(2)))
- if (C->isNullValue()) {
- LI.setOperand(0, SI->getOperand(1));
- return &LI;
- }
- }
- }
- return 0;
-}
-
-/// InstCombineStoreToCast - Fold store V, (cast P) -> store (cast V), P
-/// when possible. This makes it generally easy to do alias analysis and/or
-/// SROA/mem2reg of the memory object.
-static Instruction *InstCombineStoreToCast(InstCombiner &IC, StoreInst &SI) {
- User *CI = cast<User>(SI.getOperand(1));
- Value *CastOp = CI->getOperand(0);
-
- const Type *DestPTy = cast<PointerType>(CI->getType())->getElementType();
- const PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType());
- if (SrcTy == 0) return 0;
-
- const Type *SrcPTy = SrcTy->getElementType();
-
- if (!DestPTy->isInteger() && !isa<PointerType>(DestPTy))
- return 0;
-
- /// NewGEPIndices - If SrcPTy is an aggregate type, we can emit a "noop gep"
- /// to its first element. This allows us to handle things like:
- /// store i32 xxx, (bitcast {foo*, float}* %P to i32*)
- /// on 32-bit hosts.
- SmallVector<Value*, 4> NewGEPIndices;
-
- // If the source is an array, the code below will not succeed. Check to
- // see if a trivial 'gep P, 0, 0' will help matters. Only do this for
- // constants.
- if (isa<ArrayType>(SrcPTy) || isa<StructType>(SrcPTy)) {
- // Index through pointer.
- Constant *Zero = Constant::getNullValue(Type::getInt32Ty(SI.getContext()));
- NewGEPIndices.push_back(Zero);
-
- while (1) {
- if (const StructType *STy = dyn_cast<StructType>(SrcPTy)) {
- if (!STy->getNumElements()) /* Struct can be empty {} */
- break;
- NewGEPIndices.push_back(Zero);
- SrcPTy = STy->getElementType(0);
- } else if (const ArrayType *ATy = dyn_cast<ArrayType>(SrcPTy)) {
- NewGEPIndices.push_back(Zero);
- SrcPTy = ATy->getElementType();
- } else {
- break;
+ // Otherwise, if the offset is non-zero, we need to find out if there is a
+ // field at Offset in 'A's type. If so, we can pull the cast through the
+ // GEP.
+ SmallVector<Value*, 8> NewIndices;
+ const Type *InTy =
+ cast<PointerType>(BCI->getOperand(0)->getType())->getElementType();
+ if (FindElementAtOffset(InTy, Offset, NewIndices)) {
+ Value *NGEP = GEP.isInBounds() ?
+ Builder->CreateInBoundsGEP(BCI->getOperand(0), NewIndices.begin(),
+ NewIndices.end()) :
+ Builder->CreateGEP(BCI->getOperand(0), NewIndices.begin(),
+ NewIndices.end());
+
+ if (NGEP->getType() == GEP.getType())
+ return ReplaceInstUsesWith(GEP, NGEP);
+ NGEP->takeName(&GEP);
+ return new BitCastInst(NGEP, GEP.getType());
}
}
+ }
- SrcTy = PointerType::get(SrcPTy, SrcTy->getAddressSpace());
- }
-
- if (!SrcPTy->isInteger() && !isa<PointerType>(SrcPTy))
- return 0;
-
- // If the pointers point into different address spaces or if they point to
- // values with different sizes, we can't do the transformation.
- if (!IC.getTargetData() ||
- SrcTy->getAddressSpace() !=
- cast<PointerType>(CI->getType())->getAddressSpace() ||
- IC.getTargetData()->getTypeSizeInBits(SrcPTy) !=
- IC.getTargetData()->getTypeSizeInBits(DestPTy))
- return 0;
-
- // Okay, we are casting from one integer or pointer type to another of
- // the same size. Instead of casting the pointer before
- // the store, cast the value to be stored.
- Value *NewCast;
- Value *SIOp0 = SI.getOperand(0);
- Instruction::CastOps opcode = Instruction::BitCast;
- const Type* CastSrcTy = SIOp0->getType();
- const Type* CastDstTy = SrcPTy;
- if (isa<PointerType>(CastDstTy)) {
- if (CastSrcTy->isInteger())
- opcode = Instruction::IntToPtr;
- } else if (isa<IntegerType>(CastDstTy)) {
- if (isa<PointerType>(SIOp0->getType()))
- opcode = Instruction::PtrToInt;
- }
-
- // SIOp0 is a pointer to aggregate and this is a store to the first field,
- // emit a GEP to index into its first field.
- if (!NewGEPIndices.empty())
- CastOp = IC.Builder->CreateInBoundsGEP(CastOp, NewGEPIndices.begin(),
- NewGEPIndices.end());
-
- NewCast = IC.Builder->CreateCast(opcode, SIOp0, CastDstTy,
- SIOp0->getName()+".c");
- return new StoreInst(NewCast, CastOp);
-}
-
-/// equivalentAddressValues - Test if A and B will obviously have the same
-/// value. This includes recognizing that %t0 and %t1 will have the same
-/// value in code like this:
-/// %t0 = getelementptr \@a, 0, 3
-/// store i32 0, i32* %t0
-/// %t1 = getelementptr \@a, 0, 3
-/// %t2 = load i32* %t1
-///
-static bool equivalentAddressValues(Value *A, Value *B) {
- // Test if the values are trivially equivalent.
- if (A == B) return true;
-
- // Test if the values come form identical arithmetic instructions.
- // This uses isIdenticalToWhenDefined instead of isIdenticalTo because
- // its only used to compare two uses within the same basic block, which
- // means that they'll always either have the same value or one of them
- // will have an undefined value.
- if (isa<BinaryOperator>(A) ||
- isa<CastInst>(A) ||
- isa<PHINode>(A) ||
- isa<GetElementPtrInst>(A))
- if (Instruction *BI = dyn_cast<Instruction>(B))
- if (cast<Instruction>(A)->isIdenticalToWhenDefined(BI))
- return true;
-
- // Otherwise they may not be equivalent.
- return false;
-}
-
-// If this instruction has two uses, one of which is a llvm.dbg.declare,
-// return the llvm.dbg.declare.
-DbgDeclareInst *InstCombiner::hasOneUsePlusDeclare(Value *V) {
- if (!V->hasNUses(2))
- return 0;
- for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
- UI != E; ++UI) {
- if (DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(UI))
- return DI;
- if (isa<BitCastInst>(UI) && UI->hasOneUse()) {
- if (DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(UI->use_begin()))
- return DI;
- }
- }
return 0;
}
-Instruction *InstCombiner::visitStoreInst(StoreInst &SI) {
- Value *Val = SI.getOperand(0);
- Value *Ptr = SI.getOperand(1);
-
- // If the RHS is an alloca with a single use, zapify the store, making the
- // alloca dead.
- // If the RHS is an alloca with a two uses, the other one being a
- // llvm.dbg.declare, zapify the store and the declare, making the
- // alloca dead. We must do this to prevent declare's from affecting
- // codegen.
- if (!SI.isVolatile()) {
- if (Ptr->hasOneUse()) {
- if (isa<AllocaInst>(Ptr)) {
- EraseInstFromFunction(SI);
- ++NumCombined;
- return 0;
- }
- if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Ptr)) {
- if (isa<AllocaInst>(GEP->getOperand(0))) {
- if (GEP->getOperand(0)->hasOneUse()) {
- EraseInstFromFunction(SI);
- ++NumCombined;
- return 0;
- }
- if (DbgDeclareInst *DI = hasOneUsePlusDeclare(GEP->getOperand(0))) {
- EraseInstFromFunction(*DI);
- EraseInstFromFunction(SI);
- ++NumCombined;
- return 0;
- }
- }
- }
- }
- if (DbgDeclareInst *DI = hasOneUsePlusDeclare(Ptr)) {
- EraseInstFromFunction(*DI);
- EraseInstFromFunction(SI);
- ++NumCombined;
- return 0;
- }
- }
+Instruction *InstCombiner::visitFree(Instruction &FI) {
+ Value *Op = FI.getOperand(1);
- // Attempt to improve the alignment.
- if (TD) {
- unsigned KnownAlign =
- GetOrEnforceKnownAlignment(Ptr, TD->getPrefTypeAlignment(Val->getType()));
- if (KnownAlign >
- (SI.getAlignment() == 0 ? TD->getABITypeAlignment(Val->getType()) :
- SI.getAlignment()))
- SI.setAlignment(KnownAlign);
+ // free undef -> unreachable.
+ if (isa<UndefValue>(Op)) {
+ // Insert a new store to null because we cannot modify the CFG here.
+ new StoreInst(ConstantInt::getTrue(FI.getContext()),
+ UndefValue::get(Type::getInt1PtrTy(FI.getContext())), &FI);
+ return EraseInstFromFunction(FI);
}
+
+ // If we have 'free null' delete the instruction. This can happen in stl code
+ // when lots of inlining happens.
+ if (isa<ConstantPointerNull>(Op))
+ return EraseInstFromFunction(FI);
- // Do really simple DSE, to catch cases where there are several consecutive
- // stores to the same location, separated by a few arithmetic operations. This
- // situation often occurs with bitfield accesses.
- BasicBlock::iterator BBI = &SI;
- for (unsigned ScanInsts = 6; BBI != SI.getParent()->begin() && ScanInsts;
- --ScanInsts) {
- --BBI;
- // Don't count debug info directives, lest they affect codegen,
- // and we skip pointer-to-pointer bitcasts, which are NOPs.
- // It is necessary for correctness to skip those that feed into a
- // llvm.dbg.declare, as these are not present when debugging is off.
- if (isa<DbgInfoIntrinsic>(BBI) ||
- (isa<BitCastInst>(BBI) && isa<PointerType>(BBI->getType()))) {
- ScanInsts++;
- continue;
- }
-
- if (StoreInst *PrevSI = dyn_cast<StoreInst>(BBI)) {
- // Prev store isn't volatile, and stores to the same location?
- if (!PrevSI->isVolatile() &&equivalentAddressValues(PrevSI->getOperand(1),
- SI.getOperand(1))) {
- ++NumDeadStore;
- ++BBI;
- EraseInstFromFunction(*PrevSI);
- continue;
+ // If we have a malloc call whose only use is a free call, delete both.
+ if (isMalloc(Op)) {
+ if (CallInst* CI = extractMallocCallFromBitCast(Op)) {
+ if (Op->hasOneUse() && CI->hasOneUse()) {
+ EraseInstFromFunction(FI);
+ EraseInstFromFunction(*CI);
+ return EraseInstFromFunction(*cast<Instruction>(Op));
}
- break;
- }
-
- // If this is a load, we have to stop. However, if the loaded value is from
- // the pointer we're loading and is producing the pointer we're storing,
- // then *this* store is dead (X = load P; store X -> P).
- if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) {
- if (LI == Val && equivalentAddressValues(LI->getOperand(0), Ptr) &&
- !SI.isVolatile()) {
- EraseInstFromFunction(SI);
- ++NumCombined;
- return 0;
+ } else {
+ // Op is a call to malloc
+ if (Op->hasOneUse()) {
+ EraseInstFromFunction(FI);
+ return EraseInstFromFunction(*cast<Instruction>(Op));
}
- // Otherwise, this is a load from some other location. Stores before it
- // may not be dead.
- break;
- }
-
- // Don't skip over loads or things that can modify memory.
- if (BBI->mayWriteToMemory() || BBI->mayReadFromMemory())
- break;
- }
-
-
- if (SI.isVolatile()) return 0; // Don't hack volatile stores.
-
- // store X, null -> turns into 'unreachable' in SimplifyCFG
- if (isa<ConstantPointerNull>(Ptr) && SI.getPointerAddressSpace() == 0) {
- if (!isa<UndefValue>(Val)) {
- SI.setOperand(0, UndefValue::get(Val->getType()));
- if (Instruction *U = dyn_cast<Instruction>(Val))
- Worklist.Add(U); // Dropped a use.
- ++NumCombined;
}
- return 0; // Do not modify these!
}
- // store undef, Ptr -> noop
- if (isa<UndefValue>(Val)) {
- EraseInstFromFunction(SI);
- ++NumCombined;
- return 0;
- }
-
- // If the pointer destination is a cast, see if we can fold the cast into the
- // source instead.
- if (isa<CastInst>(Ptr))
- if (Instruction *Res = InstCombineStoreToCast(*this, SI))
- return Res;
- if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr))
- if (CE->isCast())
- if (Instruction *Res = InstCombineStoreToCast(*this, SI))
- return Res;
-
-
- // If this store is the last instruction in the basic block (possibly
- // excepting debug info instructions and the pointer bitcasts that feed
- // into them), and if the block ends with an unconditional branch, try
- // to move it to the successor block.
- BBI = &SI;
- do {
- ++BBI;
- } while (isa<DbgInfoIntrinsic>(BBI) ||
- (isa<BitCastInst>(BBI) && isa<PointerType>(BBI->getType())));
- if (BranchInst *BI = dyn_cast<BranchInst>(BBI))
- if (BI->isUnconditional())
- if (SimplifyStoreAtEndOfBlock(SI))
- return 0; // xform done!
-
return 0;
}
-/// SimplifyStoreAtEndOfBlock - Turn things like:
-/// if () { *P = v1; } else { *P = v2 }
-/// into a phi node with a store in the successor.
-///
-/// Simplify things like:
-/// *P = v1; if () { *P = v2; }
-/// into a phi node with a store in the successor.
-///
-bool InstCombiner::SimplifyStoreAtEndOfBlock(StoreInst &SI) {
- BasicBlock *StoreBB = SI.getParent();
-
- // Check to see if the successor block has exactly two incoming edges. If
- // so, see if the other predecessor contains a store to the same location.
- // if so, insert a PHI node (if needed) and move the stores down.
- BasicBlock *DestBB = StoreBB->getTerminator()->getSuccessor(0);
-
- // Determine whether Dest has exactly two predecessors and, if so, compute
- // the other predecessor.
- pred_iterator PI = pred_begin(DestBB);
- BasicBlock *OtherBB = 0;
- if (*PI != StoreBB)
- OtherBB = *PI;
- ++PI;
- if (PI == pred_end(DestBB))
- return false;
-
- if (*PI != StoreBB) {
- if (OtherBB)
- return false;
- OtherBB = *PI;
- }
- if (++PI != pred_end(DestBB))
- return false;
-
- // Bail out if all the relevant blocks aren't distinct (this can happen,
- // for example, if SI is in an infinite loop)
- if (StoreBB == DestBB || OtherBB == DestBB)
- return false;
-
- // Verify that the other block ends in a branch and is not otherwise empty.
- BasicBlock::iterator BBI = OtherBB->getTerminator();
- BranchInst *OtherBr = dyn_cast<BranchInst>(BBI);
- if (!OtherBr || BBI == OtherBB->begin())
- return false;
-
- // If the other block ends in an unconditional branch, check for the 'if then
- // else' case. there is an instruction before the branch.
- StoreInst *OtherStore = 0;
- if (OtherBr->isUnconditional()) {
- --BBI;
- // Skip over debugging info.
- while (isa<DbgInfoIntrinsic>(BBI) ||
- (isa<BitCastInst>(BBI) && isa<PointerType>(BBI->getType()))) {
- if (BBI==OtherBB->begin())
- return false;
- --BBI;
- }
- // If this isn't a store, isn't a store to the same location, or if the
- // alignments differ, bail out.
- OtherStore = dyn_cast<StoreInst>(BBI);
- if (!OtherStore || OtherStore->getOperand(1) != SI.getOperand(1) ||
- OtherStore->getAlignment() != SI.getAlignment())
- return false;
- } else {
- // Otherwise, the other block ended with a conditional branch. If one of the
- // destinations is StoreBB, then we have the if/then case.
- if (OtherBr->getSuccessor(0) != StoreBB &&
- OtherBr->getSuccessor(1) != StoreBB)
- return false;
-
- // Okay, we know that OtherBr now goes to Dest and StoreBB, so this is an
- // if/then triangle. See if there is a store to the same ptr as SI that
- // lives in OtherBB.
- for (;; --BBI) {
- // Check to see if we find the matching store.
- if ((OtherStore = dyn_cast<StoreInst>(BBI))) {
- if (OtherStore->getOperand(1) != SI.getOperand(1) ||
- OtherStore->getAlignment() != SI.getAlignment())
- return false;
- break;
- }
- // If we find something that may be using or overwriting the stored
- // value, or if we run out of instructions, we can't do the xform.
- if (BBI->mayReadFromMemory() || BBI->mayWriteToMemory() ||
- BBI == OtherBB->begin())
- return false;
- }
-
- // In order to eliminate the store in OtherBr, we have to
- // make sure nothing reads or overwrites the stored value in
- // StoreBB.
- for (BasicBlock::iterator I = StoreBB->begin(); &*I != &SI; ++I) {
- // FIXME: This should really be AA driven.
- if (I->mayReadFromMemory() || I->mayWriteToMemory())
- return false;
- }
- }
-
- // Insert a PHI node now if we need it.
- Value *MergedVal = OtherStore->getOperand(0);
- if (MergedVal != SI.getOperand(0)) {
- PHINode *PN = PHINode::Create(MergedVal->getType(), "storemerge");
- PN->reserveOperandSpace(2);
- PN->addIncoming(SI.getOperand(0), SI.getParent());
- PN->addIncoming(OtherStore->getOperand(0), OtherBB);
- MergedVal = InsertNewInstBefore(PN, DestBB->front());
- }
-
- // Advance to a place where it is safe to insert the new store and
- // insert it.
- BBI = DestBB->getFirstNonPHI();
- InsertNewInstBefore(new StoreInst(MergedVal, SI.getOperand(1),
- OtherStore->isVolatile(),
- SI.getAlignment()), *BBI);
-
- // Nuke the old stores.
- EraseInstFromFunction(SI);
- EraseInstFromFunction(*OtherStore);
- ++NumCombined;
- return true;
-}
Instruction *InstCombiner::visitBranchInst(BranchInst &BI) {
return 0;
}
-/// CheapToScalarize - Return true if the value is cheaper to scalarize than it
-/// is to leave as a vector operation.
-static bool CheapToScalarize(Value *V, bool isConstant) {
- if (isa<ConstantAggregateZero>(V))
- return true;
- if (ConstantVector *C = dyn_cast<ConstantVector>(V)) {
- if (isConstant) return true;
- // If all elts are the same, we can extract.
- Constant *Op0 = C->getOperand(0);
- for (unsigned i = 1; i < C->getNumOperands(); ++i)
- if (C->getOperand(i) != Op0)
- return false;
- return true;
- }
- Instruction *I = dyn_cast<Instruction>(V);
- if (!I) return false;
-
- // Insert element gets simplified to the inserted element or is deleted if
- // this is constant idx extract element and its a constant idx insertelt.
- if (I->getOpcode() == Instruction::InsertElement && isConstant &&
- isa<ConstantInt>(I->getOperand(2)))
- return true;
- if (I->getOpcode() == Instruction::Load && I->hasOneUse())
- return true;
- if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I))
- if (BO->hasOneUse() &&
- (CheapToScalarize(BO->getOperand(0), isConstant) ||
- CheapToScalarize(BO->getOperand(1), isConstant)))
- return true;
- if (CmpInst *CI = dyn_cast<CmpInst>(I))
- if (CI->hasOneUse() &&
- (CheapToScalarize(CI->getOperand(0), isConstant) ||
- CheapToScalarize(CI->getOperand(1), isConstant)))
- return true;
-
- return false;
-}
-
-/// Read and decode a shufflevector mask.
-///
-/// It turns undef elements into values that are larger than the number of
-/// elements in the input.
-static std::vector<unsigned> getShuffleMask(const ShuffleVectorInst *SVI) {
- unsigned NElts = SVI->getType()->getNumElements();
- if (isa<ConstantAggregateZero>(SVI->getOperand(2)))
- return std::vector<unsigned>(NElts, 0);
- if (isa<UndefValue>(SVI->getOperand(2)))
- return std::vector<unsigned>(NElts, 2*NElts);
-
- std::vector<unsigned> Result;
- const ConstantVector *CP = cast<ConstantVector>(SVI->getOperand(2));
- for (User::const_op_iterator i = CP->op_begin(), e = CP->op_end(); i!=e; ++i)
- if (isa<UndefValue>(*i))
- Result.push_back(NElts*2); // undef -> 8
- else
- Result.push_back(cast<ConstantInt>(*i)->getZExtValue());
- return Result;
-}
-
-/// FindScalarElement - Given a vector and an element number, see if the scalar
-/// value is already around as a register, for example if it were inserted then
-/// extracted from the vector.
-static Value *FindScalarElement(Value *V, unsigned EltNo) {
- assert(isa<VectorType>(V->getType()) && "Not looking at a vector?");
- const VectorType *PTy = cast<VectorType>(V->getType());
- unsigned Width = PTy->getNumElements();
- if (EltNo >= Width) // Out of range access.
- return UndefValue::get(PTy->getElementType());
-
- if (isa<UndefValue>(V))
- return UndefValue::get(PTy->getElementType());
- else if (isa<ConstantAggregateZero>(V))
- return Constant::getNullValue(PTy->getElementType());
- else if (ConstantVector *CP = dyn_cast<ConstantVector>(V))
- return CP->getOperand(EltNo);
- else if (InsertElementInst *III = dyn_cast<InsertElementInst>(V)) {
- // If this is an insert to a variable element, we don't know what it is.
- if (!isa<ConstantInt>(III->getOperand(2)))
- return 0;
- unsigned IIElt = cast<ConstantInt>(III->getOperand(2))->getZExtValue();
-
- // If this is an insert to the element we are looking for, return the
- // inserted value.
- if (EltNo == IIElt)
- return III->getOperand(1);
-
- // Otherwise, the insertelement doesn't modify the value, recurse on its
- // vector input.
- return FindScalarElement(III->getOperand(0), EltNo);
- } else if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(V)) {
- unsigned LHSWidth =
- cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements();
- unsigned InEl = getShuffleMask(SVI)[EltNo];
- if (InEl < LHSWidth)
- return FindScalarElement(SVI->getOperand(0), InEl);
- else if (InEl < LHSWidth*2)
- return FindScalarElement(SVI->getOperand(1), InEl - LHSWidth);
- else
- return UndefValue::get(PTy->getElementType());
- }
-
- // Otherwise, we don't know.
- return 0;
-}
-
-Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) {
- // If vector val is undef, replace extract with scalar undef.
- if (isa<UndefValue>(EI.getOperand(0)))
- return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
-
- // If vector val is constant 0, replace extract with scalar 0.
- if (isa<ConstantAggregateZero>(EI.getOperand(0)))
- return ReplaceInstUsesWith(EI, Constant::getNullValue(EI.getType()));
-
- if (ConstantVector *C = dyn_cast<ConstantVector>(EI.getOperand(0))) {
- // If vector val is constant with all elements the same, replace EI with
- // that element. When the elements are not identical, we cannot replace yet
- // (we do that below, but only when the index is constant).
- Constant *op0 = C->getOperand(0);
- for (unsigned i = 1; i != C->getNumOperands(); ++i)
- if (C->getOperand(i) != op0) {
- op0 = 0;
- break;
- }
- if (op0)
- return ReplaceInstUsesWith(EI, op0);
- }
-
- // If extracting a specified index from the vector, see if we can recursively
- // find a previously computed scalar that was inserted into the vector.
- if (ConstantInt *IdxC = dyn_cast<ConstantInt>(EI.getOperand(1))) {
- unsigned IndexVal = IdxC->getZExtValue();
- unsigned VectorWidth = EI.getVectorOperandType()->getNumElements();
-
- // If this is extracting an invalid index, turn this into undef, to avoid
- // crashing the code below.
- if (IndexVal >= VectorWidth)
- return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
-
- // This instruction only demands the single element from the input vector.
- // If the input vector has a single use, simplify it based on this use
- // property.
- if (EI.getOperand(0)->hasOneUse() && VectorWidth != 1) {
- APInt UndefElts(VectorWidth, 0);
- APInt DemandedMask(VectorWidth, 1 << IndexVal);
- if (Value *V = SimplifyDemandedVectorElts(EI.getOperand(0),
- DemandedMask, UndefElts)) {
- EI.setOperand(0, V);
- return &EI;
- }
- }
-
- if (Value *Elt = FindScalarElement(EI.getOperand(0), IndexVal))
- return ReplaceInstUsesWith(EI, Elt);
-
- // If the this extractelement is directly using a bitcast from a vector of
- // the same number of elements, see if we can find the source element from
- // it. In this case, we will end up needing to bitcast the scalars.
- if (BitCastInst *BCI = dyn_cast<BitCastInst>(EI.getOperand(0))) {
- if (const VectorType *VT =
- dyn_cast<VectorType>(BCI->getOperand(0)->getType()))
- if (VT->getNumElements() == VectorWidth)
- if (Value *Elt = FindScalarElement(BCI->getOperand(0), IndexVal))
- return new BitCastInst(Elt, EI.getType());
- }
- }
-
- if (Instruction *I = dyn_cast<Instruction>(EI.getOperand(0))) {
- // Push extractelement into predecessor operation if legal and
- // profitable to do so
- if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
- if (I->hasOneUse() &&
- CheapToScalarize(BO, isa<ConstantInt>(EI.getOperand(1)))) {
- Value *newEI0 =
- Builder->CreateExtractElement(BO->getOperand(0), EI.getOperand(1),
- EI.getName()+".lhs");
- Value *newEI1 =
- Builder->CreateExtractElement(BO->getOperand(1), EI.getOperand(1),
- EI.getName()+".rhs");
- return BinaryOperator::Create(BO->getOpcode(), newEI0, newEI1);
- }
- } else if (InsertElementInst *IE = dyn_cast<InsertElementInst>(I)) {
- // Extracting the inserted element?
- if (IE->getOperand(2) == EI.getOperand(1))
- return ReplaceInstUsesWith(EI, IE->getOperand(1));
- // If the inserted and extracted elements are constants, they must not
- // be the same value, extract from the pre-inserted value instead.
- if (isa<Constant>(IE->getOperand(2)) && isa<Constant>(EI.getOperand(1))) {
- Worklist.AddValue(EI.getOperand(0));
- EI.setOperand(0, IE->getOperand(0));
- return &EI;
- }
- } else if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(I)) {
- // If this is extracting an element from a shufflevector, figure out where
- // it came from and extract from the appropriate input element instead.
- if (ConstantInt *Elt = dyn_cast<ConstantInt>(EI.getOperand(1))) {
- unsigned SrcIdx = getShuffleMask(SVI)[Elt->getZExtValue()];
- Value *Src;
- unsigned LHSWidth =
- cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements();
-
- if (SrcIdx < LHSWidth)
- Src = SVI->getOperand(0);
- else if (SrcIdx < LHSWidth*2) {
- SrcIdx -= LHSWidth;
- Src = SVI->getOperand(1);
- } else {
- return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
- }
- return ExtractElementInst::Create(Src,
- ConstantInt::get(Type::getInt32Ty(EI.getContext()),
- SrcIdx, false));
- }
- }
- // FIXME: Canonicalize extractelement(bitcast) -> bitcast(extractelement)
- }
- return 0;
-}
-
-/// CollectSingleShuffleElements - If V is a shuffle of values that ONLY returns
-/// elements from either LHS or RHS, return the shuffle mask and true.
-/// Otherwise, return false.
-static bool CollectSingleShuffleElements(Value *V, Value *LHS, Value *RHS,
- std::vector<Constant*> &Mask) {
- assert(V->getType() == LHS->getType() && V->getType() == RHS->getType() &&
- "Invalid CollectSingleShuffleElements");
- unsigned NumElts = cast<VectorType>(V->getType())->getNumElements();
-
- if (isa<UndefValue>(V)) {
- Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(V->getContext())));
- return true;
- }
-
- if (V == LHS) {
- for (unsigned i = 0; i != NumElts; ++i)
- Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()), i));
- return true;
- }
-
- if (V == RHS) {
- for (unsigned i = 0; i != NumElts; ++i)
- Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()),
- i+NumElts));
- return true;
- }
-
- if (InsertElementInst *IEI = dyn_cast<InsertElementInst>(V)) {
- // If this is an insert of an extract from some other vector, include it.
- Value *VecOp = IEI->getOperand(0);
- Value *ScalarOp = IEI->getOperand(1);
- Value *IdxOp = IEI->getOperand(2);
-
- if (!isa<ConstantInt>(IdxOp))
- return false;
- unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
-
- if (isa<UndefValue>(ScalarOp)) { // inserting undef into vector.
- // Okay, we can handle this if the vector we are insertinting into is
- // transitively ok.
- if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) {
- // If so, update the mask to reflect the inserted undef.
- Mask[InsertedIdx] = UndefValue::get(Type::getInt32Ty(V->getContext()));
- return true;
- }
- } else if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)){
- if (isa<ConstantInt>(EI->getOperand(1)) &&
- EI->getOperand(0)->getType() == V->getType()) {
- unsigned ExtractedIdx =
- cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
-
- // This must be extracting from either LHS or RHS.
- if (EI->getOperand(0) == LHS || EI->getOperand(0) == RHS) {
- // Okay, we can handle this if the vector we are insertinting into is
- // transitively ok.
- if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) {
- // If so, update the mask to reflect the inserted value.
- if (EI->getOperand(0) == LHS) {
- Mask[InsertedIdx % NumElts] =
- ConstantInt::get(Type::getInt32Ty(V->getContext()),
- ExtractedIdx);
- } else {
- assert(EI->getOperand(0) == RHS);
- Mask[InsertedIdx % NumElts] =
- ConstantInt::get(Type::getInt32Ty(V->getContext()),
- ExtractedIdx+NumElts);
-
- }
- return true;
- }
- }
- }
- }
- }
- // TODO: Handle shufflevector here!
-
- return false;
-}
-
-/// CollectShuffleElements - We are building a shuffle of V, using RHS as the
-/// RHS of the shuffle instruction, if it is not null. Return a shuffle mask
-/// that computes V and the LHS value of the shuffle.
-static Value *CollectShuffleElements(Value *V, std::vector<Constant*> &Mask,
- Value *&RHS) {
- assert(isa<VectorType>(V->getType()) &&
- (RHS == 0 || V->getType() == RHS->getType()) &&
- "Invalid shuffle!");
- unsigned NumElts = cast<VectorType>(V->getType())->getNumElements();
-
- if (isa<UndefValue>(V)) {
- Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(V->getContext())));
- return V;
- } else if (isa<ConstantAggregateZero>(V)) {
- Mask.assign(NumElts, ConstantInt::get(Type::getInt32Ty(V->getContext()),0));
- return V;
- } else if (InsertElementInst *IEI = dyn_cast<InsertElementInst>(V)) {
- // If this is an insert of an extract from some other vector, include it.
- Value *VecOp = IEI->getOperand(0);
- Value *ScalarOp = IEI->getOperand(1);
- Value *IdxOp = IEI->getOperand(2);
-
- if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) {
- if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) &&
- EI->getOperand(0)->getType() == V->getType()) {
- unsigned ExtractedIdx =
- cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
- unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
-
- // Either the extracted from or inserted into vector must be RHSVec,
- // otherwise we'd end up with a shuffle of three inputs.
- if (EI->getOperand(0) == RHS || RHS == 0) {
- RHS = EI->getOperand(0);
- Value *V = CollectShuffleElements(VecOp, Mask, RHS);
- Mask[InsertedIdx % NumElts] =
- ConstantInt::get(Type::getInt32Ty(V->getContext()),
- NumElts+ExtractedIdx);
- return V;
- }
-
- if (VecOp == RHS) {
- Value *V = CollectShuffleElements(EI->getOperand(0), Mask, RHS);
- // Everything but the extracted element is replaced with the RHS.
- for (unsigned i = 0; i != NumElts; ++i) {
- if (i != InsertedIdx)
- Mask[i] = ConstantInt::get(Type::getInt32Ty(V->getContext()),
- NumElts+i);
- }
- return V;
- }
-
- // If this insertelement is a chain that comes from exactly these two
- // vectors, return the vector and the effective shuffle.
- if (CollectSingleShuffleElements(IEI, EI->getOperand(0), RHS, Mask))
- return EI->getOperand(0);
- }
- }
- }
- // TODO: Handle shufflevector here!
-
- // Otherwise, can't do anything fancy. Return an identity vector.
- for (unsigned i = 0; i != NumElts; ++i)
- Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()), i));
- return V;
-}
-
-Instruction *InstCombiner::visitInsertElementInst(InsertElementInst &IE) {
- Value *VecOp = IE.getOperand(0);
- Value *ScalarOp = IE.getOperand(1);
- Value *IdxOp = IE.getOperand(2);
-
- // Inserting an undef or into an undefined place, remove this.
- if (isa<UndefValue>(ScalarOp) || isa<UndefValue>(IdxOp))
- ReplaceInstUsesWith(IE, VecOp);
-
- // If the inserted element was extracted from some other vector, and if the
- // indexes are constant, try to turn this into a shufflevector operation.
- if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) {
- if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) &&
- EI->getOperand(0)->getType() == IE.getType()) {
- unsigned NumVectorElts = IE.getType()->getNumElements();
- unsigned ExtractedIdx =
- cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
- unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
-
- if (ExtractedIdx >= NumVectorElts) // Out of range extract.
- return ReplaceInstUsesWith(IE, VecOp);
-
- if (InsertedIdx >= NumVectorElts) // Out of range insert.
- return ReplaceInstUsesWith(IE, UndefValue::get(IE.getType()));
-
- // If we are extracting a value from a vector, then inserting it right
- // back into the same place, just use the input vector.
- if (EI->getOperand(0) == VecOp && ExtractedIdx == InsertedIdx)
- return ReplaceInstUsesWith(IE, VecOp);
-
- // If this insertelement isn't used by some other insertelement, turn it
- // (and any insertelements it points to), into one big shuffle.
- if (!IE.hasOneUse() || !isa<InsertElementInst>(IE.use_back())) {
- std::vector<Constant*> Mask;
- Value *RHS = 0;
- Value *LHS = CollectShuffleElements(&IE, Mask, RHS);
- if (RHS == 0) RHS = UndefValue::get(LHS->getType());
- // We now have a shuffle of LHS, RHS, Mask.
- return new ShuffleVectorInst(LHS, RHS,
- ConstantVector::get(Mask));
- }
- }
- }
-
- unsigned VWidth = cast<VectorType>(VecOp->getType())->getNumElements();
- APInt UndefElts(VWidth, 0);
- APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
- if (SimplifyDemandedVectorElts(&IE, AllOnesEltMask, UndefElts))
- return &IE;
-
- return 0;
-}
-
-
-Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
- Value *LHS = SVI.getOperand(0);
- Value *RHS = SVI.getOperand(1);
- std::vector<unsigned> Mask = getShuffleMask(&SVI);
-
- bool MadeChange = false;
-
- // Undefined shuffle mask -> undefined value.
- if (isa<UndefValue>(SVI.getOperand(2)))
- return ReplaceInstUsesWith(SVI, UndefValue::get(SVI.getType()));
-
- unsigned VWidth = cast<VectorType>(SVI.getType())->getNumElements();
-
- if (VWidth != cast<VectorType>(LHS->getType())->getNumElements())
- return 0;
-
- APInt UndefElts(VWidth, 0);
- APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
- if (SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
- LHS = SVI.getOperand(0);
- RHS = SVI.getOperand(1);
- MadeChange = true;
- }
-
- // Canonicalize shuffle(x ,x,mask) -> shuffle(x, undef,mask')
- // Canonicalize shuffle(undef,x,mask) -> shuffle(x, undef,mask').
- if (LHS == RHS || isa<UndefValue>(LHS)) {
- if (isa<UndefValue>(LHS) && LHS == RHS) {
- // shuffle(undef,undef,mask) -> undef.
- return ReplaceInstUsesWith(SVI, LHS);
- }
-
- // Remap any references to RHS to use LHS.
- std::vector<Constant*> Elts;
- for (unsigned i = 0, e = Mask.size(); i != e; ++i) {
- if (Mask[i] >= 2*e)
- Elts.push_back(UndefValue::get(Type::getInt32Ty(SVI.getContext())));
- else {
- if ((Mask[i] >= e && isa<UndefValue>(RHS)) ||
- (Mask[i] < e && isa<UndefValue>(LHS))) {
- Mask[i] = 2*e; // Turn into undef.
- Elts.push_back(UndefValue::get(Type::getInt32Ty(SVI.getContext())));
- } else {
- Mask[i] = Mask[i] % e; // Force to LHS.
- Elts.push_back(ConstantInt::get(Type::getInt32Ty(SVI.getContext()),
- Mask[i]));
- }
- }
- }
- SVI.setOperand(0, SVI.getOperand(1));
- SVI.setOperand(1, UndefValue::get(RHS->getType()));
- SVI.setOperand(2, ConstantVector::get(Elts));
- LHS = SVI.getOperand(0);
- RHS = SVI.getOperand(1);
- MadeChange = true;
- }
-
- // Analyze the shuffle, are the LHS or RHS and identity shuffles?
- bool isLHSID = true, isRHSID = true;
-
- for (unsigned i = 0, e = Mask.size(); i != e; ++i) {
- if (Mask[i] >= e*2) continue; // Ignore undef values.
- // Is this an identity shuffle of the LHS value?
- isLHSID &= (Mask[i] == i);
-
- // Is this an identity shuffle of the RHS value?
- isRHSID &= (Mask[i]-e == i);
- }
-
- // Eliminate identity shuffles.
- if (isLHSID) return ReplaceInstUsesWith(SVI, LHS);
- if (isRHSID) return ReplaceInstUsesWith(SVI, RHS);
-
- // If the LHS is a shufflevector itself, see if we can combine it with this
- // one without producing an unusual shuffle. Here we are really conservative:
- // we are absolutely afraid of producing a shuffle mask not in the input
- // program, because the code gen may not be smart enough to turn a merged
- // shuffle into two specific shuffles: it may produce worse code. As such,
- // we only merge two shuffles if the result is one of the two input shuffle
- // masks. In this case, merging the shuffles just removes one instruction,
- // which we know is safe. This is good for things like turning:
- // (splat(splat)) -> splat.
- if (ShuffleVectorInst *LHSSVI = dyn_cast<ShuffleVectorInst>(LHS)) {
- if (isa<UndefValue>(RHS)) {
- std::vector<unsigned> LHSMask = getShuffleMask(LHSSVI);
-
- if (LHSMask.size() == Mask.size()) {
- std::vector<unsigned> NewMask;
- for (unsigned i = 0, e = Mask.size(); i != e; ++i)
- if (Mask[i] >= e)
- NewMask.push_back(2*e);
- else
- NewMask.push_back(LHSMask[Mask[i]]);
-
- // If the result mask is equal to the src shuffle or this
- // shuffle mask, do the replacement.
- if (NewMask == LHSMask || NewMask == Mask) {
- unsigned LHSInNElts =
- cast<VectorType>(LHSSVI->getOperand(0)->getType())->
- getNumElements();
- std::vector<Constant*> Elts;
- for (unsigned i = 0, e = NewMask.size(); i != e; ++i) {
- if (NewMask[i] >= LHSInNElts*2) {
- Elts.push_back(UndefValue::get(
- Type::getInt32Ty(SVI.getContext())));
- } else {
- Elts.push_back(ConstantInt::get(
- Type::getInt32Ty(SVI.getContext()),
- NewMask[i]));
- }
- }
- return new ShuffleVectorInst(LHSSVI->getOperand(0),
- LHSSVI->getOperand(1),
- ConstantVector::get(Elts));
- }
- }
- }
- }
-
- return MadeChange ? &SVI : 0;
-}
-
BasicBlock::iterator InsertPos = DestBlock->getFirstNonPHI();
- CopyPrecedingStopPoint(I, InsertPos);
I->moveBefore(InsertPos);
++NumSunkInst;
return true;
SmallPtrSet<ConstantExpr*, 64> FoldedConstants;
- while (!Worklist.empty()) {
- BB = Worklist.back();
- Worklist.pop_back();
+ do {
+ BB = Worklist.pop_back_val();
// We have now visited this block! If we've already been here, ignore it.
if (!Visited.insert(BB)) continue;
continue;
}
-
-
if (TD) {
// See if we can constant fold its operands.
for (User::op_iterator i = Inst->op_begin(), e = Inst->op_end();
}
}
}
-
InstrsForInstCombineWorklist.push_back(Inst);
}
for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
Worklist.push_back(TI->getSuccessor(i));
- }
+ } while (!Worklist.empty());
// Once we've found all of the instructions to add to instcombine's worklist,
// add them in reverse order. This way instcombine will visit from the top
projects / oota-llvm.git / blobdiff