#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
+#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/Support/ConstantRange.h"
-#include "llvm/Support/GetElementPtrTypeIterator.h"
-#include "llvm/Support/PatternMatch.h"
+#include "llvm/IR/PatternMatch.h"
#include "llvm/Target/TargetLibraryInfo.h"
using namespace llvm;
using namespace PatternMatch;
+#define DEBUG_TYPE "instcombine"
+
static ConstantInt *getOne(Constant *C) {
return ConstantInt::get(cast<IntegerType>(C->getType()), 1);
}
FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP, GlobalVariable *GV,
CmpInst &ICI, ConstantInt *AndCst) {
// We need TD information to know the pointer size unless this is inbounds.
- if (!GEP->isInBounds() && TD == 0)
- return 0;
+ if (!GEP->isInBounds() && !DL)
+ return nullptr;
Constant *Init = GV->getInitializer();
if (!isa<ConstantArray>(Init) && !isa<ConstantDataArray>(Init))
- return 0;
+ return nullptr;
uint64_t ArrayElementCount = Init->getType()->getArrayNumElements();
- if (ArrayElementCount > 1024) return 0; // Don't blow up on huge arrays.
+ if (ArrayElementCount > 1024) return nullptr; // Don't blow up on huge arrays.
// There are many forms of this optimization we can handle, for now, just do
// the simple index into a single-dimensional array.
!isa<ConstantInt>(GEP->getOperand(1)) ||
!cast<ConstantInt>(GEP->getOperand(1))->isZero() ||
isa<Constant>(GEP->getOperand(2)))
- return 0;
+ return nullptr;
// Check that indices after the variable are constants and in-range for the
// type they index. Collect the indices. This is typically for arrays of
Type *EltTy = Init->getType()->getArrayElementType();
for (unsigned i = 3, e = GEP->getNumOperands(); i != e; ++i) {
ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(i));
- if (Idx == 0) return 0; // Variable index.
+ if (!Idx) return nullptr; // Variable index.
uint64_t IdxVal = Idx->getZExtValue();
- if ((unsigned)IdxVal != IdxVal) return 0; // Too large array index.
+ if ((unsigned)IdxVal != IdxVal) return nullptr; // Too large array index.
if (StructType *STy = dyn_cast<StructType>(EltTy))
EltTy = STy->getElementType(IdxVal);
else if (ArrayType *ATy = dyn_cast<ArrayType>(EltTy)) {
- if (IdxVal >= ATy->getNumElements()) return 0;
+ if (IdxVal >= ATy->getNumElements()) return nullptr;
EltTy = ATy->getElementType();
} else {
- return 0; // Unknown type.
+ return nullptr; // Unknown type.
}
LaterIndices.push_back(IdxVal);
Constant *CompareRHS = cast<Constant>(ICI.getOperand(1));
for (unsigned i = 0, e = ArrayElementCount; i != e; ++i) {
Constant *Elt = Init->getAggregateElement(i);
- if (Elt == 0) return 0;
+ if (!Elt) return nullptr;
// If this is indexing an array of structures, get the structure element.
if (!LaterIndices.empty())
// Find out if the comparison would be true or false for the i'th element.
Constant *C = ConstantFoldCompareInstOperands(ICI.getPredicate(), Elt,
- CompareRHS, TD, TLI);
+ CompareRHS, DL, TLI);
// If the result is undef for this element, ignore it.
if (isa<UndefValue>(C)) {
// Extend range state machines to cover this element in case there is an
// If we can't compute the result for any of the elements, we have to give
// up evaluating the entire conditional.
- if (!isa<ConstantInt>(C)) return 0;
+ if (!isa<ConstantInt>(C)) return nullptr;
// Otherwise, we know if the comparison is true or false for this element,
// update our state machines.
if ((i & 8) == 0 && i >= 64 && SecondTrueElement == Overdefined &&
SecondFalseElement == Overdefined && TrueRangeEnd == Overdefined &&
FalseRangeEnd == Overdefined)
- return 0;
+ return nullptr;
}
// Now that we've scanned the entire array, emit our new comparison(s). We
// index down like the GEP would do implicitly. We don't have to do this for
// an inbounds GEP because the index can't be out of range.
if (!GEP->isInBounds()) {
- Type *IntPtrTy = TD->getIntPtrType(GEP->getType());
+ Type *IntPtrTy = DL->getIntPtrType(GEP->getType());
unsigned PtrSize = IntPtrTy->getIntegerBitWidth();
if (Idx->getType()->getPrimitiveSizeInBits() > PtrSize)
Idx = Builder->CreateTrunc(Idx, IntPtrTy);
// of this load, replace it with computation that does:
// ((magic_cst >> i) & 1) != 0
{
- Type *Ty = 0;
+ Type *Ty = nullptr;
// Look for an appropriate type:
// - The type of Idx if the magic fits
// - Default to i32
if (ArrayElementCount <= Idx->getType()->getIntegerBitWidth())
Ty = Idx->getType();
- else if (TD)
- Ty = TD->getSmallestLegalIntType(Init->getContext(), ArrayElementCount);
+ else if (DL)
+ Ty = DL->getSmallestLegalIntType(Init->getContext(), ArrayElementCount);
else if (ArrayElementCount <= 32)
Ty = Type::getInt32Ty(Init->getContext());
- if (Ty != 0) {
+ if (Ty) {
Value *V = Builder->CreateIntCast(Idx, Ty, false);
V = Builder->CreateLShr(ConstantInt::get(Ty, MagicBitvector), V);
V = Builder->CreateAnd(ConstantInt::get(Ty, 1), V);
}
}
- return 0;
+ return nullptr;
}
/// If we can't emit an optimized form for this expression, this returns null.
///
static Value *EvaluateGEPOffsetExpression(User *GEP, InstCombiner &IC) {
- DataLayout &TD = *IC.getDataLayout();
+ const DataLayout &DL = *IC.getDataLayout();
gep_type_iterator GTI = gep_type_begin(GEP);
// Check to see if this gep only has a single variable index. If so, and if
// Handle a struct index, which adds its field offset to the pointer.
if (StructType *STy = dyn_cast<StructType>(*GTI)) {
- Offset += TD.getStructLayout(STy)->getElementOffset(CI->getZExtValue());
+ Offset += DL.getStructLayout(STy)->getElementOffset(CI->getZExtValue());
} else {
- uint64_t Size = TD.getTypeAllocSize(GTI.getIndexedType());
+ uint64_t Size = DL.getTypeAllocSize(GTI.getIndexedType());
Offset += Size*CI->getSExtValue();
}
} else {
// If there are no variable indices, we must have a constant offset, just
// evaluate it the general way.
- if (i == e) return 0;
+ if (i == e) return nullptr;
Value *VariableIdx = GEP->getOperand(i);
// Determine the scale factor of the variable element. For example, this is
// 4 if the variable index is into an array of i32.
- uint64_t VariableScale = TD.getTypeAllocSize(GTI.getIndexedType());
+ uint64_t VariableScale = DL.getTypeAllocSize(GTI.getIndexedType());
// Verify that there are no other variable indices. If so, emit the hard way.
for (++i, ++GTI; i != e; ++i, ++GTI) {
ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i));
- if (!CI) return 0;
+ if (!CI) return nullptr;
// Compute the aggregate offset of constant indices.
if (CI->isZero()) continue;
// Handle a struct index, which adds its field offset to the pointer.
if (StructType *STy = dyn_cast<StructType>(*GTI)) {
- Offset += TD.getStructLayout(STy)->getElementOffset(CI->getZExtValue());
+ Offset += DL.getStructLayout(STy)->getElementOffset(CI->getZExtValue());
} else {
- uint64_t Size = TD.getTypeAllocSize(GTI.getIndexedType());
+ uint64_t Size = DL.getTypeAllocSize(GTI.getIndexedType());
Offset += Size*CI->getSExtValue();
}
}
// Okay, we know we have a single variable index, which must be a
// pointer/array/vector index. If there is no offset, life is simple, return
// the index.
- Type *IntPtrTy = TD.getIntPtrType(GEP->getOperand(0)->getType());
+ Type *IntPtrTy = DL.getIntPtrType(GEP->getOperand(0)->getType());
unsigned IntPtrWidth = IntPtrTy->getIntegerBitWidth();
if (Offset == 0) {
// Cast to intptrty in case a truncation occurs. If an extension is needed,
// multiple of the variable scale.
int64_t NewOffs = Offset / (int64_t)VariableScale;
if (Offset != NewOffs*(int64_t)VariableScale)
- return 0;
+ return nullptr;
// Okay, we can do this evaluation. Start by converting the index to intptr.
if (VariableIdx->getType() != IntPtrTy)
// e.g. "&foo[0] <s &foo[1]" can't be folded to "true" because "foo" could be
// the maximum signed value for the pointer type.
if (ICmpInst::isSigned(Cond))
- return 0;
+ return nullptr;
- // Look through bitcasts.
- if (BitCastInst *BCI = dyn_cast<BitCastInst>(RHS))
- RHS = BCI->getOperand(0);
+ // Look through bitcasts and addrspacecasts. We do not however want to remove
+ // 0 GEPs.
+ if (!isa<GetElementPtrInst>(RHS))
+ RHS = RHS->stripPointerCasts();
Value *PtrBase = GEPLHS->getOperand(0);
- if (TD && PtrBase == RHS && GEPLHS->isInBounds()) {
+ if (DL && PtrBase == RHS && GEPLHS->isInBounds()) {
// ((gep Ptr, OFFSET) cmp Ptr) ---> (OFFSET cmp 0).
// This transformation (ignoring the base and scales) is valid because we
// know pointers can't overflow since the gep is inbounds. See if we can
Value *Offset = EvaluateGEPOffsetExpression(GEPLHS, *this);
// If not, synthesize the offset the hard way.
- if (Offset == 0)
+ if (!Offset)
Offset = EmitGEPOffset(GEPLHS);
return new ICmpInst(ICmpInst::getSignedPredicate(Cond), Offset,
Constant::getNullValue(Offset->getType()));
// If we're comparing GEPs with two base pointers that only differ in type
// and both GEPs have only constant indices or just one use, then fold
// the compare with the adjusted indices.
- if (TD && GEPLHS->isInBounds() && GEPRHS->isInBounds() &&
+ if (DL && GEPLHS->isInBounds() && GEPRHS->isInBounds() &&
(GEPLHS->hasAllConstantIndices() || GEPLHS->hasOneUse()) &&
(GEPRHS->hasAllConstantIndices() || GEPRHS->hasOneUse()) &&
PtrBase->stripPointerCasts() ==
GEPRHS->getOperand(0)->stripPointerCasts()) {
+ Value *LOffset = EmitGEPOffset(GEPLHS);
+ Value *ROffset = EmitGEPOffset(GEPRHS);
+
+ // If we looked through an addrspacecast between different sized address
+ // spaces, the LHS and RHS pointers are different sized
+ // integers. Truncate to the smaller one.
+ Type *LHSIndexTy = LOffset->getType();
+ Type *RHSIndexTy = ROffset->getType();
+ if (LHSIndexTy != RHSIndexTy) {
+ if (LHSIndexTy->getPrimitiveSizeInBits() <
+ RHSIndexTy->getPrimitiveSizeInBits()) {
+ ROffset = Builder->CreateTrunc(ROffset, LHSIndexTy);
+ } else
+ LOffset = Builder->CreateTrunc(LOffset, RHSIndexTy);
+ }
+
Value *Cmp = Builder->CreateICmp(ICmpInst::getSignedPredicate(Cond),
- EmitGEPOffset(GEPLHS),
- EmitGEPOffset(GEPRHS));
+ LOffset, ROffset);
return ReplaceInstUsesWith(I, Cmp);
}
// Otherwise, the base pointers are different and the indices are
// different, bail out.
- return 0;
+ return nullptr;
}
// If one of the GEPs has all zero indices, recurse.
- bool AllZeros = true;
- for (unsigned i = 1, e = GEPLHS->getNumOperands(); i != e; ++i)
- if (!isa<Constant>(GEPLHS->getOperand(i)) ||
- !cast<Constant>(GEPLHS->getOperand(i))->isNullValue()) {
- AllZeros = false;
- break;
- }
- if (AllZeros)
+ if (GEPLHS->hasAllZeroIndices())
return FoldGEPICmp(GEPRHS, GEPLHS->getOperand(0),
ICmpInst::getSwappedPredicate(Cond), I);
// If the other GEP has all zero indices, recurse.
- AllZeros = true;
- for (unsigned i = 1, e = GEPRHS->getNumOperands(); i != e; ++i)
- if (!isa<Constant>(GEPRHS->getOperand(i)) ||
- !cast<Constant>(GEPRHS->getOperand(i))->isNullValue()) {
- AllZeros = false;
- break;
- }
- if (AllZeros)
+ if (GEPRHS->hasAllZeroIndices())
return FoldGEPICmp(GEPLHS, GEPRHS->getOperand(0), Cond, I);
bool GEPsInBounds = GEPLHS->isInBounds() && GEPRHS->isInBounds();
// Only lower this if the icmp is the only user of the GEP or if we expect
// the result to fold to a constant!
- if (TD &&
+ if (DL &&
GEPsInBounds &&
(isa<ConstantExpr>(GEPLHS) || GEPLHS->hasOneUse()) &&
(isa<ConstantExpr>(GEPRHS) || GEPRHS->hasOneUse())) {
return new ICmpInst(ICmpInst::getSignedPredicate(Cond), L, R);
}
}
- return 0;
+ return nullptr;
}
/// FoldICmpAddOpCst - Fold "icmp pred (X+CI), X".
Instruction *InstCombiner::FoldICmpAddOpCst(Instruction &ICI,
Value *X, ConstantInt *CI,
ICmpInst::Predicate Pred) {
- // If we have X+0, exit early (simplifying logic below) and let it get folded
- // elsewhere. icmp X+0, X -> icmp X, X
- if (CI->isZero()) {
- bool isTrue = ICmpInst::isTrueWhenEqual(Pred);
- return ReplaceInstUsesWith(ICI, ConstantInt::get(ICI.getType(), isTrue));
- }
-
- // (X+4) == X -> false.
- if (Pred == ICmpInst::ICMP_EQ)
- return ReplaceInstUsesWith(ICI, Builder->getFalse());
-
- // (X+4) != X -> true.
- if (Pred == ICmpInst::ICMP_NE)
- return ReplaceInstUsesWith(ICI, Builder->getTrue());
-
// From this point on, we know that (X+C <= X) --> (X+C < X) because C != 0,
// so the values can never be equal. Similarly for all other "or equals"
// operators.
// if it finds it.
bool DivIsSigned = DivI->getOpcode() == Instruction::SDiv;
if (!ICI.isEquality() && DivIsSigned != ICI.isSigned())
- return 0;
+ return nullptr;
if (DivRHS->isZero())
- return 0; // The ProdOV computation fails on divide by zero.
+ return nullptr; // The ProdOV computation fails on divide by zero.
if (DivIsSigned && DivRHS->isAllOnesValue())
- return 0; // The overflow computation also screws up here
+ return nullptr; // The overflow computation also screws up here
if (DivRHS->isOne()) {
// This eliminates some funny cases with INT_MIN.
ICI.setOperand(0, DivI->getOperand(0)); // X/1 == X.
// overflow variable is set to 0 if it's corresponding bound variable is valid
// -1 if overflowed off the bottom end, or +1 if overflowed off the top end.
int LoOverflow = 0, HiOverflow = 0;
- Constant *LoBound = 0, *HiBound = 0;
+ Constant *LoBound = nullptr, *HiBound = nullptr;
if (!DivIsSigned) { // udiv
// e.g. X/5 op 3 --> [15, 20)
HiBound = cast<ConstantInt>(ConstantExpr::getNeg(RangeSize));
if (HiBound == DivRHS) { // -INTMIN = INTMIN
HiOverflow = 1; // [INTMIN+1, overflow)
- HiBound = 0; // e.g. X/INTMIN = 0 --> X > INTMIN
+ HiBound = nullptr; // e.g. X/INTMIN = 0 --> X > INTMIN
}
} else if (CmpRHSV.isStrictlyPositive()) { // (X / neg) op pos
// e.g. X/-5 op 3 --> [-19, -14)
uint32_t TypeBits = CmpRHSV.getBitWidth();
uint32_t ShAmtVal = (uint32_t)ShAmt->getLimitedValue(TypeBits);
if (ShAmtVal >= TypeBits || ShAmtVal == 0)
- return 0;
+ return nullptr;
if (!ICI.isEquality()) {
// If we have an unsigned comparison and an ashr, we can't simplify this.
// Similarly for signed comparisons with lshr.
if (ICI.isSigned() != (Shr->getOpcode() == Instruction::AShr))
- return 0;
+ return nullptr;
// Otherwise, all lshr and most exact ashr's are equivalent to a udiv/sdiv
// by a power of 2. Since we already have logic to simplify these,
// transform to div and then simplify the resultant comparison.
if (Shr->getOpcode() == Instruction::AShr &&
(!Shr->isExact() || ShAmtVal == TypeBits - 1))
- return 0;
+ return nullptr;
// Revisit the shift (to delete it).
Worklist.Add(Shr);
// If the builder folded the binop, just return it.
BinaryOperator *TheDiv = dyn_cast<BinaryOperator>(Tmp);
- if (TheDiv == 0)
+ if (!TheDiv)
return &ICI;
// Otherwise, fold this div/compare.
Mask, Shr->getName()+".mask");
return new ICmpInst(ICI.getPredicate(), And, ShiftedCmpRHS);
}
- return 0;
+ return nullptr;
+}
+
+/// FoldICmpCstShrCst - Handle "(icmp eq/ne (ashr/lshr const2, A), const1)" ->
+/// (icmp eq/ne A, Log2(const2/const1)) ->
+/// (icmp eq/ne A, Log2(const2) - Log2(const1)).
+Instruction *InstCombiner::FoldICmpCstShrCst(ICmpInst &I, Value *Op, Value *A,
+ ConstantInt *CI1,
+ ConstantInt *CI2) {
+ assert(I.isEquality() && "Cannot fold icmp gt/lt");
+
+ auto getConstant = [&I, this](bool IsTrue) {
+ if (I.getPredicate() == I.ICMP_NE)
+ IsTrue = !IsTrue;
+ return ReplaceInstUsesWith(I, ConstantInt::get(I.getType(), IsTrue));
+ };
+
+ auto getICmp = [&I](CmpInst::Predicate Pred, Value *LHS, Value *RHS) {
+ if (I.getPredicate() == I.ICMP_NE)
+ Pred = CmpInst::getInversePredicate(Pred);
+ return new ICmpInst(Pred, LHS, RHS);
+ };
+
+ APInt AP1 = CI1->getValue();
+ APInt AP2 = CI2->getValue();
+
+ // Don't bother doing any work for cases which InstSimplify handles.
+ if (AP2 == 0)
+ return nullptr;
+ bool IsAShr = isa<AShrOperator>(Op);
+ if (IsAShr) {
+ if (AP2.isAllOnesValue())
+ return nullptr;
+ if (AP2.isNegative() != AP1.isNegative())
+ return nullptr;
+ if (AP2.sgt(AP1))
+ return nullptr;
+ }
+
+ if (!AP1)
+ // 'A' must be large enough to shift out the highest set bit.
+ return getICmp(I.ICMP_UGT, A,
+ ConstantInt::get(A->getType(), AP2.logBase2()));
+
+ if (AP1 == AP2)
+ return getICmp(I.ICMP_EQ, A, ConstantInt::getNullValue(A->getType()));
+
+ // Get the distance between the highest bit that's set.
+ int Shift;
+ // Both the constants are negative, take their positive to calculate log.
+ if (IsAShr && AP1.isNegative())
+ // Get the ones' complement of AP2 and AP1 when computing the distance.
+ Shift = (~AP2).logBase2() - (~AP1).logBase2();
+ else
+ Shift = AP2.logBase2() - AP1.logBase2();
+
+ if (Shift > 0) {
+ if (IsAShr ? AP1 == AP2.ashr(Shift) : AP1 == AP2.lshr(Shift))
+ return getICmp(I.ICMP_EQ, A, ConstantInt::get(A->getType(), Shift));
+ }
+ // Shifting const2 will never be equal to const1.
+ return getConstant(false);
}
+/// FoldICmpCstShlCst - Handle "(icmp eq/ne (shl const2, A), const1)" ->
+/// (icmp eq/ne A, TrailingZeros(const1) - TrailingZeros(const2)).
+Instruction *InstCombiner::FoldICmpCstShlCst(ICmpInst &I, Value *Op, Value *A,
+ ConstantInt *CI1,
+ ConstantInt *CI2) {
+ assert(I.isEquality() && "Cannot fold icmp gt/lt");
+
+ auto getConstant = [&I, this](bool IsTrue) {
+ if (I.getPredicate() == I.ICMP_NE)
+ IsTrue = !IsTrue;
+ return ReplaceInstUsesWith(I, ConstantInt::get(I.getType(), IsTrue));
+ };
+
+ auto getICmp = [&I](CmpInst::Predicate Pred, Value *LHS, Value *RHS) {
+ if (I.getPredicate() == I.ICMP_NE)
+ Pred = CmpInst::getInversePredicate(Pred);
+ return new ICmpInst(Pred, LHS, RHS);
+ };
+
+ APInt AP1 = CI1->getValue();
+ APInt AP2 = CI2->getValue();
+
+ // Don't bother doing any work for cases which InstSimplify handles.
+ if (AP2 == 0)
+ return nullptr;
+
+ unsigned AP2TrailingZeros = AP2.countTrailingZeros();
+
+ if (!AP1 && AP2TrailingZeros != 0)
+ return getICmp(I.ICMP_UGE, A,
+ ConstantInt::get(A->getType(), AP2.getBitWidth() - AP2TrailingZeros));
+
+ if (AP1 == AP2)
+ return getICmp(I.ICMP_EQ, A, ConstantInt::getNullValue(A->getType()));
+
+ // Get the distance between the lowest bits that are set.
+ int Shift = AP1.countTrailingZeros() - AP2TrailingZeros;
+
+ if (Shift > 0 && AP2.shl(Shift) == AP1)
+ return getICmp(I.ICMP_EQ, A, ConstantInt::get(A->getType(), Shift));
+
+ // Shifting const2 will never be equal to const1.
+ return getConstant(false);
+}
/// visitICmpInstWithInstAndIntCst - Handle "icmp (instr, intcst)".
///
unsigned DstBits = LHSI->getType()->getPrimitiveSizeInBits(),
SrcBits = LHSI->getOperand(0)->getType()->getPrimitiveSizeInBits();
APInt KnownZero(SrcBits, 0), KnownOne(SrcBits, 0);
- ComputeMaskedBits(LHSI->getOperand(0), KnownZero, KnownOne);
+ computeKnownBits(LHSI->getOperand(0), KnownZero, KnownOne, 0, &ICI);
// If all the high bits are known, we can do this xform.
if ((KnownZero|KnownOne).countLeadingOnes() >= SrcBits-DstBits) {
// access.
BinaryOperator *Shift = dyn_cast<BinaryOperator>(LHSI->getOperand(0));
if (Shift && !Shift->isShift())
- Shift = 0;
+ Shift = nullptr;
ConstantInt *ShAmt;
- ShAmt = Shift ? dyn_cast<ConstantInt>(Shift->getOperand(1)) : 0;
+ ShAmt = Shift ? dyn_cast<ConstantInt>(Shift->getOperand(1)) : nullptr;
// This seemingly simple opportunity to fold away a shift turns out to
// be rather complicated. See PR17827
return &ICI;
}
+ // (icmp pred (and (or (lshr X, Y), X), 1), 0) -->
+ // (icmp pred (and X, (or (shl 1, Y), 1), 0))
+ //
+ // iff pred isn't signed
+ {
+ Value *X, *Y, *LShr;
+ if (!ICI.isSigned() && RHSV == 0) {
+ if (match(LHSI->getOperand(1), m_One())) {
+ Constant *One = cast<Constant>(LHSI->getOperand(1));
+ Value *Or = LHSI->getOperand(0);
+ if (match(Or, m_Or(m_Value(LShr), m_Value(X))) &&
+ match(LShr, m_LShr(m_Specific(X), m_Value(Y)))) {
+ unsigned UsesRemoved = 0;
+ if (LHSI->hasOneUse())
+ ++UsesRemoved;
+ if (Or->hasOneUse())
+ ++UsesRemoved;
+ if (LShr->hasOneUse())
+ ++UsesRemoved;
+ Value *NewOr = nullptr;
+ // Compute X & ((1 << Y) | 1)
+ if (auto *C = dyn_cast<Constant>(Y)) {
+ if (UsesRemoved >= 1)
+ NewOr =
+ ConstantExpr::getOr(ConstantExpr::getNUWShl(One, C), One);
+ } else {
+ if (UsesRemoved >= 3)
+ NewOr = Builder->CreateOr(Builder->CreateShl(One, Y,
+ LShr->getName(),
+ /*HasNUW=*/true),
+ One, Or->getName());
+ }
+ if (NewOr) {
+ Value *NewAnd = Builder->CreateAnd(X, NewOr, LHSI->getName());
+ ICI.setOperand(0, NewAnd);
+ return &ICI;
+ }
+ }
+ }
+ }
+ }
+
// Replace ((X & AndCst) > RHSV) with ((X & AndCst) != 0), if any
// bit set in (X & AndCst) will produce a result greater than RHSV.
if (ICI.getPredicate() == ICmpInst::ICMP_UGT) {
unsigned RHSLog2 = RHSV.logBase2();
// (1 << X) >= 2147483648 -> X >= 31 -> X == 31
- // (1 << X) > 2147483648 -> X > 31 -> false
- // (1 << X) <= 2147483648 -> X <= 31 -> true
// (1 << X) < 2147483648 -> X < 31 -> X != 31
if (RHSLog2 == TypeBits-1) {
if (Pred == ICmpInst::ICMP_UGE)
Pred = ICmpInst::ICMP_EQ;
- else if (Pred == ICmpInst::ICMP_UGT)
- return ReplaceInstUsesWith(ICI, Builder->getFalse());
- else if (Pred == ICmpInst::ICMP_ULE)
- return ReplaceInstUsesWith(ICI, Builder->getTrue());
else if (Pred == ICmpInst::ICMP_ULT)
Pred = ICmpInst::ICMP_NE;
}
if (RHSVIsPowerOf2)
return new ICmpInst(
Pred, X, ConstantInt::get(RHS->getType(), RHSV.logBase2()));
-
- return ReplaceInstUsesWith(
- ICI, Pred == ICmpInst::ICMP_EQ ? Builder->getFalse()
- : Builder->getTrue());
}
}
break;
}
}
}
- return 0;
+ return nullptr;
}
/// visitICmpInstWithCastAndCast - Handle icmp (cast x to y), (cast/cst).
// Turn icmp (ptrtoint x), (ptrtoint/c) into a compare of the input if the
// integer type is the same size as the pointer type.
- if (TD && LHSCI->getOpcode() == Instruction::PtrToInt &&
- TD->getPointerTypeSizeInBits(SrcTy) == DestTy->getIntegerBitWidth()) {
- Value *RHSOp = 0;
+ if (DL && LHSCI->getOpcode() == Instruction::PtrToInt &&
+ DL->getPointerTypeSizeInBits(SrcTy) == DestTy->getIntegerBitWidth()) {
+ Value *RHSOp = nullptr;
if (Constant *RHSC = dyn_cast<Constant>(ICI.getOperand(1))) {
RHSOp = ConstantExpr::getIntToPtr(RHSC, SrcTy);
} else if (PtrToIntInst *RHSC = dyn_cast<PtrToIntInst>(ICI.getOperand(1))) {
// Enforce this.
if (LHSCI->getOpcode() != Instruction::ZExt &&
LHSCI->getOpcode() != Instruction::SExt)
- return 0;
+ return nullptr;
bool isSignedExt = LHSCI->getOpcode() == Instruction::SExt;
bool isSignedCmp = ICI.isSigned();
// Not an extension from the same type?
RHSCIOp = CI->getOperand(0);
if (RHSCIOp->getType() != LHSCIOp->getType())
- return 0;
+ return nullptr;
// If the signedness of the two casts doesn't agree (i.e. one is a sext
// and the other is a zext), then we can't handle this.
if (CI->getOpcode() != LHSCI->getOpcode())
- return 0;
+ return nullptr;
// Deal with equality cases early.
if (ICI.isEquality())
// If we aren't dealing with a constant on the RHS, exit early
ConstantInt *CI = dyn_cast<ConstantInt>(ICI.getOperand(1));
if (!CI)
- return 0;
+ return nullptr;
// Compute the constant that would happen if we truncated to SrcTy then
// reextended to DestTy.
// by SimplifyICmpInst, so only deal with the tricky case.
if (isSignedCmp || !isSignedExt)
- return 0;
+ return nullptr;
// Evaluate the comparison for LT (we invert for GT below). LE and GE cases
// should have been folded away previously and not enter in here.
// In order to eliminate the add-with-constant, the compare can be its only
// use.
Instruction *AddWithCst = cast<Instruction>(I.getOperand(0));
- if (!AddWithCst->hasOneUse()) return 0;
+ if (!AddWithCst->hasOneUse()) return nullptr;
// If CI2 is 2^7, 2^15, 2^31, then it might be an sadd.with.overflow.
- if (!CI2->getValue().isPowerOf2()) return 0;
+ if (!CI2->getValue().isPowerOf2()) return nullptr;
unsigned NewWidth = CI2->getValue().countTrailingZeros();
- if (NewWidth != 7 && NewWidth != 15 && NewWidth != 31) return 0;
+ if (NewWidth != 7 && NewWidth != 15 && NewWidth != 31) return nullptr;
// The width of the new add formed is 1 more than the bias.
++NewWidth;
// Check to see that CI1 is an all-ones value with NewWidth bits.
if (CI1->getBitWidth() == NewWidth ||
CI1->getValue() != APInt::getLowBitsSet(CI1->getBitWidth(), NewWidth))
- return 0;
+ return nullptr;
// This is only really a signed overflow check if the inputs have been
// sign-extended; check for that condition. For example, if CI2 is 2^31 and
// the operands of the add are 64 bits wide, we need at least 33 sign bits.
unsigned NeededSignBits = CI1->getBitWidth() - NewWidth + 1;
- if (IC.ComputeNumSignBits(A) < NeededSignBits ||
- IC.ComputeNumSignBits(B) < NeededSignBits)
- return 0;
+ if (IC.ComputeNumSignBits(A, 0, &I) < NeededSignBits ||
+ IC.ComputeNumSignBits(B, 0, &I) < NeededSignBits)
+ return nullptr;
// In order to replace the original add with a narrower
// llvm.sadd.with.overflow, the only uses allowed are the add-with-constant
// and truncates that discard the high bits of the add. Verify that this is
// the case.
Instruction *OrigAdd = cast<Instruction>(AddWithCst->getOperand(0));
- for (Value::use_iterator UI = OrigAdd->use_begin(), E = OrigAdd->use_end();
- UI != E; ++UI) {
- if (*UI == AddWithCst) continue;
+ for (User *U : OrigAdd->users()) {
+ if (U == AddWithCst) continue;
// Only accept truncates for now. We would really like a nice recursive
// predicate like SimplifyDemandedBits, but which goes downwards the use-def
// chain to see which bits of a value are actually demanded. If the
// original add had another add which was then immediately truncated, we
// could still do the transformation.
- TruncInst *TI = dyn_cast<TruncInst>(*UI);
- if (TI == 0 ||
- TI->getType()->getPrimitiveSizeInBits() > NewWidth) return 0;
+ TruncInst *TI = dyn_cast<TruncInst>(U);
+ if (!TI || TI->getType()->getPrimitiveSizeInBits() > NewWidth)
+ return nullptr;
}
// If the pattern matches, truncate the inputs to the narrower type and
InstCombiner &IC) {
// Don't bother doing this transformation for pointers, don't do it for
// vectors.
- if (!isa<IntegerType>(OrigAddV->getType())) return 0;
+ if (!isa<IntegerType>(OrigAddV->getType())) return nullptr;
// If the add is a constant expr, then we don't bother transforming it.
Instruction *OrigAdd = dyn_cast<Instruction>(OrigAddV);
- if (OrigAdd == 0) return 0;
+ if (!OrigAdd) return nullptr;
Value *LHS = OrigAdd->getOperand(0), *RHS = OrigAdd->getOperand(1);
return ExtractValueInst::Create(Call, 1, "uadd.overflow");
}
+/// \brief Recognize and process idiom involving test for multiplication
+/// overflow.
+///
+/// The caller has matched a pattern of the form:
+/// I = cmp u (mul(zext A, zext B), V
+/// The function checks if this is a test for overflow and if so replaces
+/// multiplication with call to 'mul.with.overflow' intrinsic.
+///
+/// \param I Compare instruction.
+/// \param MulVal Result of 'mult' instruction. It is one of the arguments of
+/// the compare instruction. Must be of integer type.
+/// \param OtherVal The other argument of compare instruction.
+/// \returns Instruction which must replace the compare instruction, NULL if no
+/// replacement required.
+static Instruction *ProcessUMulZExtIdiom(ICmpInst &I, Value *MulVal,
+ Value *OtherVal, InstCombiner &IC) {
+ // Don't bother doing this transformation for pointers, don't do it for
+ // vectors.
+ if (!isa<IntegerType>(MulVal->getType()))
+ return nullptr;
+
+ assert(I.getOperand(0) == MulVal || I.getOperand(1) == MulVal);
+ assert(I.getOperand(0) == OtherVal || I.getOperand(1) == OtherVal);
+ Instruction *MulInstr = cast<Instruction>(MulVal);
+ assert(MulInstr->getOpcode() == Instruction::Mul);
+
+ auto *LHS = cast<ZExtOperator>(MulInstr->getOperand(0)),
+ *RHS = cast<ZExtOperator>(MulInstr->getOperand(1));
+ assert(LHS->getOpcode() == Instruction::ZExt);
+ assert(RHS->getOpcode() == Instruction::ZExt);
+ Value *A = LHS->getOperand(0), *B = RHS->getOperand(0);
+
+ // Calculate type and width of the result produced by mul.with.overflow.
+ Type *TyA = A->getType(), *TyB = B->getType();
+ unsigned WidthA = TyA->getPrimitiveSizeInBits(),
+ WidthB = TyB->getPrimitiveSizeInBits();
+ unsigned MulWidth;
+ Type *MulType;
+ if (WidthB > WidthA) {
+ MulWidth = WidthB;
+ MulType = TyB;
+ } else {
+ MulWidth = WidthA;
+ MulType = TyA;
+ }
+
+ // In order to replace the original mul with a narrower mul.with.overflow,
+ // all uses must ignore upper bits of the product. The number of used low
+ // bits must be not greater than the width of mul.with.overflow.
+ if (MulVal->hasNUsesOrMore(2))
+ for (User *U : MulVal->users()) {
+ if (U == &I)
+ continue;
+ if (TruncInst *TI = dyn_cast<TruncInst>(U)) {
+ // Check if truncation ignores bits above MulWidth.
+ unsigned TruncWidth = TI->getType()->getPrimitiveSizeInBits();
+ if (TruncWidth > MulWidth)
+ return nullptr;
+ } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(U)) {
+ // Check if AND ignores bits above MulWidth.
+ if (BO->getOpcode() != Instruction::And)
+ return nullptr;
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->getOperand(1))) {
+ const APInt &CVal = CI->getValue();
+ if (CVal.getBitWidth() - CVal.countLeadingZeros() > MulWidth)
+ return nullptr;
+ }
+ } else {
+ // Other uses prohibit this transformation.
+ return nullptr;
+ }
+ }
+
+ // Recognize patterns
+ switch (I.getPredicate()) {
+ case ICmpInst::ICMP_EQ:
+ case ICmpInst::ICMP_NE:
+ // Recognize pattern:
+ // mulval = mul(zext A, zext B)
+ // cmp eq/neq mulval, zext trunc mulval
+ if (ZExtInst *Zext = dyn_cast<ZExtInst>(OtherVal))
+ if (Zext->hasOneUse()) {
+ Value *ZextArg = Zext->getOperand(0);
+ if (TruncInst *Trunc = dyn_cast<TruncInst>(ZextArg))
+ if (Trunc->getType()->getPrimitiveSizeInBits() == MulWidth)
+ break; //Recognized
+ }
+
+ // Recognize pattern:
+ // mulval = mul(zext A, zext B)
+ // cmp eq/neq mulval, and(mulval, mask), mask selects low MulWidth bits.
+ ConstantInt *CI;
+ Value *ValToMask;
+ if (match(OtherVal, m_And(m_Value(ValToMask), m_ConstantInt(CI)))) {
+ if (ValToMask != MulVal)
+ return nullptr;
+ const APInt &CVal = CI->getValue() + 1;
+ if (CVal.isPowerOf2()) {
+ unsigned MaskWidth = CVal.logBase2();
+ if (MaskWidth == MulWidth)
+ break; // Recognized
+ }
+ }
+ return nullptr;
+
+ case ICmpInst::ICMP_UGT:
+ // Recognize pattern:
+ // mulval = mul(zext A, zext B)
+ // cmp ugt mulval, max
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal)) {
+ APInt MaxVal = APInt::getMaxValue(MulWidth);
+ MaxVal = MaxVal.zext(CI->getBitWidth());
+ if (MaxVal.eq(CI->getValue()))
+ break; // Recognized
+ }
+ return nullptr;
+
+ case ICmpInst::ICMP_UGE:
+ // Recognize pattern:
+ // mulval = mul(zext A, zext B)
+ // cmp uge mulval, max+1
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal)) {
+ APInt MaxVal = APInt::getOneBitSet(CI->getBitWidth(), MulWidth);
+ if (MaxVal.eq(CI->getValue()))
+ break; // Recognized
+ }
+ return nullptr;
+
+ case ICmpInst::ICMP_ULE:
+ // Recognize pattern:
+ // mulval = mul(zext A, zext B)
+ // cmp ule mulval, max
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal)) {
+ APInt MaxVal = APInt::getMaxValue(MulWidth);
+ MaxVal = MaxVal.zext(CI->getBitWidth());
+ if (MaxVal.eq(CI->getValue()))
+ break; // Recognized
+ }
+ return nullptr;
+
+ case ICmpInst::ICMP_ULT:
+ // Recognize pattern:
+ // mulval = mul(zext A, zext B)
+ // cmp ule mulval, max + 1
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal)) {
+ APInt MaxVal = APInt::getOneBitSet(CI->getBitWidth(), MulWidth);
+ if (MaxVal.eq(CI->getValue()))
+ break; // Recognized
+ }
+ return nullptr;
+
+ default:
+ return nullptr;
+ }
+
+ InstCombiner::BuilderTy *Builder = IC.Builder;
+ Builder->SetInsertPoint(MulInstr);
+ Module *M = I.getParent()->getParent()->getParent();
+
+ // Replace: mul(zext A, zext B) --> mul.with.overflow(A, B)
+ Value *MulA = A, *MulB = B;
+ if (WidthA < MulWidth)
+ MulA = Builder->CreateZExt(A, MulType);
+ if (WidthB < MulWidth)
+ MulB = Builder->CreateZExt(B, MulType);
+ Value *F =
+ Intrinsic::getDeclaration(M, Intrinsic::umul_with_overflow, MulType);
+ CallInst *Call = Builder->CreateCall2(F, MulA, MulB, "umul");
+ IC.Worklist.Add(MulInstr);
+
+ // If there are uses of mul result other than the comparison, we know that
+ // they are truncation or binary AND. Change them to use result of
+ // mul.with.overflow and adjust properly mask/size.
+ if (MulVal->hasNUsesOrMore(2)) {
+ Value *Mul = Builder->CreateExtractValue(Call, 0, "umul.value");
+ for (User *U : MulVal->users()) {
+ if (U == &I || U == OtherVal)
+ continue;
+ if (TruncInst *TI = dyn_cast<TruncInst>(U)) {
+ if (TI->getType()->getPrimitiveSizeInBits() == MulWidth)
+ IC.ReplaceInstUsesWith(*TI, Mul);
+ else
+ TI->setOperand(0, Mul);
+ } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(U)) {
+ assert(BO->getOpcode() == Instruction::And);
+ // Replace (mul & mask) --> zext (mul.with.overflow & short_mask)
+ ConstantInt *CI = cast<ConstantInt>(BO->getOperand(1));
+ APInt ShortMask = CI->getValue().trunc(MulWidth);
+ Value *ShortAnd = Builder->CreateAnd(Mul, ShortMask);
+ Instruction *Zext =
+ cast<Instruction>(Builder->CreateZExt(ShortAnd, BO->getType()));
+ IC.Worklist.Add(Zext);
+ IC.ReplaceInstUsesWith(*BO, Zext);
+ } else {
+ llvm_unreachable("Unexpected Binary operation");
+ }
+ IC.Worklist.Add(cast<Instruction>(U));
+ }
+ }
+ if (isa<Instruction>(OtherVal))
+ IC.Worklist.Add(cast<Instruction>(OtherVal));
+
+ // The original icmp gets replaced with the overflow value, maybe inverted
+ // depending on predicate.
+ bool Inverse = false;
+ switch (I.getPredicate()) {
+ case ICmpInst::ICMP_NE:
+ break;
+ case ICmpInst::ICMP_EQ:
+ Inverse = true;
+ break;
+ case ICmpInst::ICMP_UGT:
+ case ICmpInst::ICMP_UGE:
+ if (I.getOperand(0) == MulVal)
+ break;
+ Inverse = true;
+ break;
+ case ICmpInst::ICMP_ULT:
+ case ICmpInst::ICMP_ULE:
+ if (I.getOperand(1) == MulVal)
+ break;
+ Inverse = true;
+ break;
+ default:
+ llvm_unreachable("Unexpected predicate");
+ }
+ if (Inverse) {
+ Value *Res = Builder->CreateExtractValue(Call, 1);
+ return BinaryOperator::CreateNot(Res);
+ }
+
+ return ExtractValueInst::Create(Call, 1);
+}
+
// DemandedBitsLHSMask - When performing a comparison against a constant,
// it is possible that not all the bits in the LHS are demanded. This helper
// method computes the mask that IS demanded.
/// \brief Check if the order of \p Op0 and \p Op1 as operand in an ICmpInst
/// should be swapped.
-/// The descision is based on how many times these two operands are reused
+/// The decision is based on how many times these two operands are reused
/// as subtract operands and their positions in those instructions.
/// The rational is that several architectures use the same instruction for
/// both subtract and cmp, thus it is better if the order of those operands
// Each time Op0 is the first operand, count -1: swapping is bad, the
// subtract has already the same layout as the compare.
// Each time Op0 is the second operand, count +1: swapping is good, the
- // subtract has a diffrent layout as the compare.
+ // subtract has a different layout as the compare.
// At the end, if the benefit is greater than 0, Op0 should come second to
// expose more CSE opportunities.
int GlobalSwapBenefits = 0;
- for (Value::const_use_iterator UI = Op0->use_begin(), UIEnd = Op0->use_end(); UI != UIEnd; ++UI) {
- const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(*UI);
+ for (const User *U : Op0->users()) {
+ const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(U);
if (!BinOp || BinOp->getOpcode() != Instruction::Sub)
continue;
// If Op0 is the first argument, this is not beneficial to swap the
Changed = true;
}
- if (Value *V = SimplifyICmpInst(I.getPredicate(), Op0, Op1, TD))
+ if (Value *V = SimplifyICmpInst(I.getPredicate(), Op0, Op1, DL, TLI, DT, AT))
return ReplaceInstUsesWith(I, V);
// comparing -val or val with non-zero is the same as just comparing val
unsigned BitWidth = 0;
if (Ty->isIntOrIntVectorTy())
BitWidth = Ty->getScalarSizeInBits();
- else if (TD) // Pointers require TD info to get their size.
- BitWidth = TD->getTypeSizeInBits(Ty->getScalarType());
+ else if (DL) // Pointers require DL info to get their size.
+ BitWidth = DL->getTypeSizeInBits(Ty->getScalarType());
bool isSignBit = false;
// See if we are doing a comparison with a constant.
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
- Value *A = 0, *B = 0;
+ Value *A = nullptr, *B = nullptr;
// Match the following pattern, which is a common idiom when writing
// overflow-safe integer arithmetic function. The source performs an
Builder->getInt(CI->getValue()-1));
}
+ if (I.isEquality()) {
+ ConstantInt *CI2;
+ if (match(Op0, m_AShr(m_ConstantInt(CI2), m_Value(A))) ||
+ match(Op0, m_LShr(m_ConstantInt(CI2), m_Value(A)))) {
+ // (icmp eq/ne (ashr/lshr const2, A), const1)
+ if (Instruction *Inst = FoldICmpCstShrCst(I, Op0, A, CI, CI2))
+ return Inst;
+ }
+ if (match(Op0, m_Shl(m_ConstantInt(CI2), m_Value(A)))) {
+ // (icmp eq/ne (shl const2, A), const1)
+ if (Instruction *Inst = FoldICmpCstShlCst(I, Op0, A, CI, CI2))
+ return Inst;
+ }
+ }
+
// If this comparison is a normal comparison, it demands all
// bits, if it is a sign bit comparison, it only demands the sign bit.
bool UnusedBit;
// bit is set. If the comparison is against zero, then this is a check
// to see if *that* bit is set.
APInt Op0KnownZeroInverted = ~Op0KnownZero;
- if (~Op1KnownZero == 0 && Op0KnownZeroInverted.isPowerOf2()) {
+ if (~Op1KnownZero == 0) {
// If the LHS is an AND with the same constant, look through it.
- Value *LHS = 0;
- ConstantInt *LHSC = 0;
+ Value *LHS = nullptr;
+ ConstantInt *LHSC = nullptr;
if (!match(Op0, m_And(m_Value(LHS), m_ConstantInt(LHSC))) ||
LHSC->getValue() != Op0KnownZeroInverted)
LHS = Op0;
// If the LHS is 1 << x, and we know the result is a power of 2 like 8,
// then turn "((1 << x)&8) == 0" into "x != 3".
- Value *X = 0;
+ // or turn "((1 << x)&7) == 0" into "x > 2".
+ Value *X = nullptr;
if (match(LHS, m_Shl(m_One(), m_Value(X)))) {
- unsigned CmpVal = Op0KnownZeroInverted.countTrailingZeros();
- return new ICmpInst(ICmpInst::ICMP_NE, X,
- ConstantInt::get(X->getType(), CmpVal));
+ APInt ValToCheck = Op0KnownZeroInverted;
+ if (ValToCheck.isPowerOf2()) {
+ unsigned CmpVal = ValToCheck.countTrailingZeros();
+ return new ICmpInst(ICmpInst::ICMP_NE, X,
+ ConstantInt::get(X->getType(), CmpVal));
+ } else if ((++ValToCheck).isPowerOf2()) {
+ unsigned CmpVal = ValToCheck.countTrailingZeros() - 1;
+ return new ICmpInst(ICmpInst::ICMP_UGT, X,
+ ConstantInt::get(X->getType(), CmpVal));
+ }
}
// If the LHS is 8 >>u x, and we know the result is a power of 2 like 1,
// bit is set. If the comparison is against zero, then this is a check
// to see if *that* bit is set.
APInt Op0KnownZeroInverted = ~Op0KnownZero;
- if (~Op1KnownZero == 0 && Op0KnownZeroInverted.isPowerOf2()) {
+ if (~Op1KnownZero == 0) {
// If the LHS is an AND with the same constant, look through it.
- Value *LHS = 0;
- ConstantInt *LHSC = 0;
+ Value *LHS = nullptr;
+ ConstantInt *LHSC = nullptr;
if (!match(Op0, m_And(m_Value(LHS), m_ConstantInt(LHSC))) ||
LHSC->getValue() != Op0KnownZeroInverted)
LHS = Op0;
// If the LHS is 1 << x, and we know the result is a power of 2 like 8,
// then turn "((1 << x)&8) != 0" into "x == 3".
- Value *X = 0;
+ // or turn "((1 << x)&7) != 0" into "x < 3".
+ Value *X = nullptr;
if (match(LHS, m_Shl(m_One(), m_Value(X)))) {
- unsigned CmpVal = Op0KnownZeroInverted.countTrailingZeros();
- return new ICmpInst(ICmpInst::ICMP_EQ, X,
- ConstantInt::get(X->getType(), CmpVal));
+ APInt ValToCheck = Op0KnownZeroInverted;
+ if (ValToCheck.isPowerOf2()) {
+ unsigned CmpVal = ValToCheck.countTrailingZeros();
+ return new ICmpInst(ICmpInst::ICMP_EQ, X,
+ ConstantInt::get(X->getType(), CmpVal));
+ } else if ((++ValToCheck).isPowerOf2()) {
+ unsigned CmpVal = ValToCheck.countTrailingZeros();
+ return new ICmpInst(ICmpInst::ICMP_ULT, X,
+ ConstantInt::get(X->getType(), CmpVal));
+ }
}
// If the LHS is 8 >>u x, and we know the result is a power of 2 like 1,
// operands has at least one user besides the compare (the select),
// which would often largely negate the benefit of folding anyway.
if (I.hasOneUse())
- if (SelectInst *SI = dyn_cast<SelectInst>(*I.use_begin()))
+ if (SelectInst *SI = dyn_cast<SelectInst>(*I.user_begin()))
if ((SI->getOperand(1) == Op0 && SI->getOperand(2) == Op1) ||
(SI->getOperand(2) == Op0 && SI->getOperand(1) == Op1))
- return 0;
+ return nullptr;
// See if we are doing a comparison between a constant and an instruction that
// can be folded into the comparison.
// If either operand of the select is a constant, we can fold the
// comparison into the select arms, which will cause one to be
// constant folded and the select turned into a bitwise or.
- Value *Op1 = 0, *Op2 = 0;
+ Value *Op1 = nullptr, *Op2 = nullptr;
if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(1)))
Op1 = ConstantExpr::getICmp(I.getPredicate(), C, RHSC);
if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(2)))
}
case Instruction::IntToPtr:
// icmp pred inttoptr(X), null -> icmp pred X, 0
- if (RHSC->isNullValue() && TD &&
- TD->getIntPtrType(RHSC->getType()) ==
+ if (RHSC->isNullValue() && DL &&
+ DL->getIntPtrType(RHSC->getType()) ==
LHSI->getOperand(0)->getType())
return new ICmpInst(I.getPredicate(), LHSI->getOperand(0),
Constant::getNullValue(LHSI->getOperand(0)->getType()));
// Analyze the case when either Op0 or Op1 is an add instruction.
// Op0 = A + B (or A and B are null); Op1 = C + D (or C and D are null).
- Value *A = 0, *B = 0, *C = 0, *D = 0;
+ Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
if (BO0 && BO0->getOpcode() == Instruction::Add)
A = BO0->getOperand(0), B = BO0->getOperand(1);
if (BO1 && BO1->getOpcode() == Instruction::Add)
C = BO1->getOperand(0), D = BO1->getOperand(1);
+ // icmp (X+cst) < 0 --> X < -cst
+ if (NoOp0WrapProblem && ICmpInst::isSigned(Pred) && match(Op1, m_Zero()))
+ if (ConstantInt *RHSC = dyn_cast_or_null<ConstantInt>(B))
+ if (!RHSC->isMinValue(/*isSigned=*/true))
+ return new ICmpInst(Pred, A, ConstantExpr::getNeg(RHSC));
+
// icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
if ((A == Op1 || B == Op1) && NoOp0WrapProblem)
return new ICmpInst(Pred, A == Op1 ? B : A,
// Analyze the case when either Op0 or Op1 is a sub instruction.
// Op0 = A - B (or A and B are null); Op1 = C - D (or C and D are null).
- A = 0; B = 0; C = 0; D = 0;
+ A = nullptr; B = nullptr; C = nullptr; D = nullptr;
if (BO0 && BO0->getOpcode() == Instruction::Sub)
A = BO0->getOperand(0), B = BO0->getOperand(1);
if (BO1 && BO1->getOpcode() == Instruction::Sub)
BO0->hasOneUse() && BO1->hasOneUse())
return new ICmpInst(Pred, D, B);
- BinaryOperator *SRem = NULL;
+ // icmp (0-X) < cst --> x > -cst
+ if (NoOp0WrapProblem && ICmpInst::isSigned(Pred)) {
+ Value *X;
+ if (match(BO0, m_Neg(m_Value(X))))
+ if (ConstantInt *RHSC = dyn_cast<ConstantInt>(Op1))
+ if (!RHSC->isMinValue(/*isSigned=*/true))
+ return new ICmpInst(I.getSwappedPredicate(), X,
+ ConstantExpr::getNeg(RHSC));
+ }
+
+ BinaryOperator *SRem = nullptr;
// icmp (srem X, Y), Y
if (BO0 && BO0->getOpcode() == Instruction::SRem &&
Op1 == BO0->getOperand(1))
// and (A & ~B) != 0 --> (A & B) == 0
// if A is a power of 2.
if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) &&
- match(Op1, m_Zero()) && isKnownToBeAPowerOfTwo(A) && I.isEquality())
+ match(Op1, m_Zero()) && isKnownToBeAPowerOfTwo(A, false,
+ 0, AT, &I, DT) &&
+ I.isEquality())
return new ICmpInst(I.getInversePredicate(),
Builder->CreateAnd(A, B),
Op1);
(Op0 == A || Op0 == B))
if (Instruction *R = ProcessUAddIdiom(I, Op1, *this))
return R;
+
+ // (zext a) * (zext b) --> llvm.umul.with.overflow.
+ if (match(Op0, m_Mul(m_ZExt(m_Value(A)), m_ZExt(m_Value(B))))) {
+ if (Instruction *R = ProcessUMulZExtIdiom(I, Op0, Op1, *this))
+ return R;
+ }
+ if (match(Op1, m_Mul(m_ZExt(m_Value(A)), m_ZExt(m_Value(B))))) {
+ if (Instruction *R = ProcessUMulZExtIdiom(I, Op1, Op0, *this))
+ return R;
+ }
}
if (I.isEquality()) {
// (X&Z) == (Y&Z) -> (X^Y) & Z == 0
if (match(Op0, m_OneUse(m_And(m_Value(A), m_Value(B)))) &&
match(Op1, m_OneUse(m_And(m_Value(C), m_Value(D))))) {
- Value *X = 0, *Y = 0, *Z = 0;
+ Value *X = nullptr, *Y = nullptr, *Z = nullptr;
if (A == C) {
X = B; Y = D; Z = A;
if (match(Op1, m_Add(m_Value(X), m_ConstantInt(Cst))) && Op0 == X)
return FoldICmpAddOpCst(I, X, Cst, I.getSwappedPredicate());
}
- return Changed ? &I : 0;
+ return Changed ? &I : nullptr;
}
/// FoldFCmp_IntToFP_Cst - Fold fcmp ([us]itofp x, cst) if possible.
Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I,
Instruction *LHSI,
Constant *RHSC) {
- if (!isa<ConstantFP>(RHSC)) return 0;
+ if (!isa<ConstantFP>(RHSC)) return nullptr;
const APFloat &RHS = cast<ConstantFP>(RHSC)->getValueAPF();
// Get the width of the mantissa. We don't want to hack on conversions that
// might lose information from the integer, e.g. "i64 -> float"
int MantissaWidth = LHSI->getType()->getFPMantissaWidth();
- if (MantissaWidth == -1) return 0; // Unknown.
+ if (MantissaWidth == -1) return nullptr; // Unknown.
// Check to see that the input is converted from an integer type that is small
// enough that preserves all bits. TODO: check here for "known" sign bits.
// If the conversion would lose info, don't hack on this.
if ((int)InputSize > MantissaWidth)
- return 0;
+ return nullptr;
// Otherwise, we can potentially simplify the comparison. We know that it
// will always come through as an integer value and we know the constant is
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Value *V = SimplifyFCmpInst(I.getPredicate(), Op0, Op1, TD))
+ if (Value *V = SimplifyFCmpInst(I.getPredicate(), Op0, Op1, DL, TLI, DT, AT))
return ReplaceInstUsesWith(I, V);
// Simplify 'fcmp pred X, X'
if (Instruction *NV = FoldFCmp_IntToFP_Cst(I, LHSI, RHSC))
return NV;
break;
- case Instruction::Select: {
- // If either operand of the select is a constant, we can fold the
- // comparison into the select arms, which will cause one to be
- // constant folded and the select turned into a bitwise or.
- Value *Op1 = 0, *Op2 = 0;
- if (LHSI->hasOneUse()) {
- if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(1))) {
- // Fold the known value into the constant operand.
- Op1 = ConstantExpr::getCompare(I.getPredicate(), C, RHSC);
- // Insert a new FCmp of the other select operand.
- Op2 = Builder->CreateFCmp(I.getPredicate(),
- LHSI->getOperand(2), RHSC, I.getName());
- } else if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(2))) {
- // Fold the known value into the constant operand.
- Op2 = ConstantExpr::getCompare(I.getPredicate(), C, RHSC);
- // Insert a new FCmp of the other select operand.
- Op1 = Builder->CreateFCmp(I.getPredicate(), LHSI->getOperand(1),
- RHSC, I.getName());
- }
- }
-
- if (Op1)
- return SelectInst::Create(LHSI->getOperand(0), Op1, Op2);
- break;
- }
case Instruction::FSub: {
// fcmp pred (fneg x), C -> fcmp swap(pred) x, -C
Value *Op;
return new FCmpInst(I.getPredicate(), LHSExt->getOperand(0),
RHSExt->getOperand(0));
- return Changed ? &I : 0;
+ return Changed ? &I : nullptr;
}
projects / oota-llvm.git / blobdiff