#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
-#include "llvm/DataLayout.h"
-#include "llvm/IntrinsicInst.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/IntrinsicInst.h"
#include "llvm/Support/ConstantRange.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/PatternMatch.h"
}
}
+/// Returns true if the exploded icmp can be expressed as a signed comparison
+/// to zero and updates the predicate accordingly.
+/// The signedness of the comparison is preserved.
+static bool isSignTest(ICmpInst::Predicate &pred, const ConstantInt *RHS) {
+ if (!ICmpInst::isSigned(pred))
+ return false;
+
+ if (RHS->isZero())
+ return ICmpInst::isRelational(pred);
+
+ if (RHS->isOne()) {
+ if (pred == ICmpInst::ICMP_SLT) {
+ pred = ICmpInst::ICMP_SLE;
+ return true;
+ }
+ } else if (RHS->isAllOnesValue()) {
+ if (pred == ICmpInst::ICMP_SGT) {
+ pred = ICmpInst::ICMP_SGE;
+ return true;
+ }
+ }
+
+ return false;
+}
+
// isHighOnes - Return true if the constant is of the form 1+0+.
// This is the same as lowones(~X).
static bool isHighOnes(const ConstantInt *CI) {
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() && TD == 0)
+ return 0;
Constant *Init = GV->getInitializer();
if (!isa<ConstantArray>(Init) && !isa<ConstantDataArray>(Init))
return 0;
-
+
uint64_t ArrayElementCount = Init->getType()->getArrayNumElements();
if (ArrayElementCount > 1024) return 0; // Don't blow up on huge arrays.
// If the index is larger than the pointer size of the target, truncate the
// 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() &&
- Idx->getType()->getPrimitiveSizeInBits() > TD->getPointerSizeInBits())
- Idx = Builder->CreateTrunc(Idx, TD->getIntPtrType(Idx->getContext()));
+ if (!GEP->isInBounds()) {
+ Type *IntPtrTy = TD->getIntPtrType(GEP->getType());
+ unsigned PtrSize = IntPtrTy->getIntegerBitWidth();
+ if (Idx->getType()->getPrimitiveSizeInBits() > PtrSize)
+ Idx = Builder->CreateTrunc(Idx, IntPtrTy);
+ }
// If the comparison is only true for one or two elements, emit direct
// comparisons.
if (SecondTrueElement != Overdefined) {
// None true -> false.
if (FirstTrueElement == Undefined)
- return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(GEP->getContext()));
+ return ReplaceInstUsesWith(ICI, Builder->getFalse());
Value *FirstTrueIdx = ConstantInt::get(Idx->getType(), FirstTrueElement);
if (SecondFalseElement != Overdefined) {
// None false -> true.
if (FirstFalseElement == Undefined)
- return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(GEP->getContext()));
+ return ReplaceInstUsesWith(ICI, Builder->getTrue());
Value *FirstFalseIdx = ConstantInt::get(Idx->getType(), FirstFalseElement);
}
- // If a 32-bit or 64-bit magic bitvector captures the entire comparison state
+ // If a magic bitvector captures the entire comparison state
// of this load, replace it with computation that does:
// ((magic_cst >> i) & 1) != 0
- if (ArrayElementCount <= 32 ||
- (TD && ArrayElementCount <= 64 && TD->isLegalInteger(64))) {
- Type *Ty;
- if (ArrayElementCount <= 32)
+ {
+ Type *Ty = 0;
+
+ // Look for an appropriate type:
+ // - The type of Idx if the magic fits
+ // - The smallest fitting legal type if we have a DataLayout
+ // - Default to i32
+ if (ArrayElementCount <= Idx->getType()->getIntegerBitWidth())
+ Ty = Idx->getType();
+ else if (TD)
+ Ty = TD->getSmallestLegalIntType(Init->getContext(), ArrayElementCount);
+ else if (ArrayElementCount <= 32)
Ty = Type::getInt32Ty(Init->getContext());
- else
- Ty = Type::getInt64Ty(Init->getContext());
- Value *V = Builder->CreateIntCast(Idx, Ty, false);
- V = Builder->CreateLShr(ConstantInt::get(Ty, MagicBitvector), V);
- V = Builder->CreateAnd(ConstantInt::get(Ty, 1), V);
- return new ICmpInst(ICmpInst::ICMP_NE, V, ConstantInt::get(Ty, 0));
+
+ if (Ty != 0) {
+ Value *V = Builder->CreateIntCast(Idx, Ty, false);
+ V = Builder->CreateLShr(ConstantInt::get(Ty, MagicBitvector), V);
+ V = Builder->CreateAnd(ConstantInt::get(Ty, 1), V);
+ return new ICmpInst(ICmpInst::ICMP_NE, V, ConstantInt::get(Ty, 0));
+ }
}
return 0;
}
}
+
+
// 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.
- unsigned IntPtrWidth = TD.getPointerSizeInBits();
+ Type *IntPtrTy = TD.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,
// we don't need to bother extending: the extension won't affect where the
// computation crosses zero.
if (VariableIdx->getType()->getPrimitiveSizeInBits() > IntPtrWidth) {
- Type *IntPtrTy = TD.getIntPtrType(VariableIdx->getContext());
VariableIdx = IC.Builder->CreateTrunc(VariableIdx, IntPtrTy);
}
return VariableIdx;
return 0;
// Okay, we can do this evaluation. Start by converting the index to intptr.
- Type *IntPtrTy = TD.getIntPtrType(VariableIdx->getContext());
if (VariableIdx->getType() != IntPtrTy)
VariableIdx = IC.Builder->CreateIntCast(VariableIdx, IntPtrTy,
true /*Signed*/);
// If all indices are the same, just compare the base pointers.
if (IndicesTheSame)
- return new ICmpInst(ICmpInst::getSignedPredicate(Cond),
- GEPLHS->getOperand(0), GEPRHS->getOperand(0));
+ return new ICmpInst(Cond, GEPLHS->getOperand(0), GEPRHS->getOperand(0));
// 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
}
if (AllZeros)
return FoldGEPICmp(GEPRHS, GEPLHS->getOperand(0),
- ICmpInst::getSwappedPredicate(Cond), I);
+ ICmpInst::getSwappedPredicate(Cond), I);
// If the other GEP has all zero indices, recurse.
AllZeros = true;
if (NumDifferences == 0) // SAME GEP?
return ReplaceInstUsesWith(I, // No comparison is needed here.
- ConstantInt::get(Type::getInt1Ty(I.getContext()),
- ICmpInst::isTrueWhenEqual(Cond)));
+ Builder->getInt1(ICmpInst::isTrueWhenEqual(Cond)));
else if (NumDifferences == 1 && GEPsInBounds) {
Value *LHSV = GEPLHS->getOperand(DiffOperand);
}
/// FoldICmpAddOpCst - Fold "icmp pred (X+CI), X".
-Instruction *InstCombiner::FoldICmpAddOpCst(ICmpInst &ICI,
+Instruction *InstCombiner::FoldICmpAddOpCst(Instruction &ICI,
Value *X, ConstantInt *CI,
- ICmpInst::Predicate Pred,
- Value *TheAdd) {
+ 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()) {
// (X+4) == X -> false.
if (Pred == ICmpInst::ICMP_EQ)
- return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(X->getContext()));
+ return ReplaceInstUsesWith(ICI, Builder->getFalse());
// (X+4) != X -> true.
if (Pred == ICmpInst::ICMP_NE)
- return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(X->getContext()));
+ 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"
// (X+ -1) >s X --> X <s (MAXSINT-(-1-1)) --> X == -128
assert(Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE);
- Constant *C = ConstantInt::get(X->getContext(), CI->getValue()-1);
+ Constant *C = Builder->getInt(CI->getValue()-1);
return new ICmpInst(ICmpInst::ICMP_SLT, X, ConstantExpr::getSub(SMax, C));
}
default: llvm_unreachable("Unhandled icmp opcode!");
case ICmpInst::ICMP_EQ:
if (LoOverflow && HiOverflow)
- return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(ICI.getContext()));
+ return ReplaceInstUsesWith(ICI, Builder->getFalse());
if (HiOverflow)
return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SGE :
ICmpInst::ICMP_UGE, X, LoBound);
DivIsSigned, true));
case ICmpInst::ICMP_NE:
if (LoOverflow && HiOverflow)
- return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(ICI.getContext()));
+ return ReplaceInstUsesWith(ICI, Builder->getTrue());
if (HiOverflow)
return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SLT :
ICmpInst::ICMP_ULT, X, LoBound);
case ICmpInst::ICMP_ULT:
case ICmpInst::ICMP_SLT:
if (LoOverflow == +1) // Low bound is greater than input range.
- return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(ICI.getContext()));
+ return ReplaceInstUsesWith(ICI, Builder->getTrue());
if (LoOverflow == -1) // Low bound is less than input range.
- return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(ICI.getContext()));
+ return ReplaceInstUsesWith(ICI, Builder->getFalse());
return new ICmpInst(Pred, X, LoBound);
case ICmpInst::ICMP_UGT:
case ICmpInst::ICMP_SGT:
if (HiOverflow == +1) // High bound greater than input range.
- return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(ICI.getContext()));
+ return ReplaceInstUsesWith(ICI, Builder->getFalse());
if (HiOverflow == -1) // High bound less than input range.
- return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(ICI.getContext()));
+ return ReplaceInstUsesWith(ICI, Builder->getTrue());
if (Pred == ICmpInst::ICMP_UGT)
return new ICmpInst(ICmpInst::ICMP_UGE, X, HiBound);
return new ICmpInst(ICmpInst::ICMP_SGE, X, HiBound);
// If we are comparing against bits always shifted out, the
// comparison cannot succeed.
APInt Comp = CmpRHSV << ShAmtVal;
- ConstantInt *ShiftedCmpRHS = ConstantInt::get(ICI.getContext(), Comp);
+ ConstantInt *ShiftedCmpRHS = Builder->getInt(Comp);
if (Shr->getOpcode() == Instruction::LShr)
Comp = Comp.lshr(ShAmtVal);
else
if (Comp != CmpRHSV) { // Comparing against a bit that we know is zero.
bool IsICMP_NE = ICI.getPredicate() == ICmpInst::ICMP_NE;
- Constant *Cst = ConstantInt::get(Type::getInt1Ty(ICI.getContext()),
- IsICMP_NE);
+ Constant *Cst = Builder->getInt1(IsICMP_NE);
return ReplaceInstUsesWith(ICI, Cst);
}
if (Shr->hasOneUse()) {
// Otherwise strength reduce the shift into an and.
APInt Val(APInt::getHighBitsSet(TypeBits, TypeBits - ShAmtVal));
- Constant *Mask = ConstantInt::get(ICI.getContext(), Val);
+ Constant *Mask = Builder->getInt(Val);
Value *And = Builder->CreateAnd(Shr->getOperand(0),
Mask, Shr->getName()+".mask");
APInt NewRHS = RHS->getValue().zext(SrcBits);
NewRHS |= KnownOne & APInt::getHighBitsSet(SrcBits, SrcBits-DstBits);
return new ICmpInst(ICI.getPredicate(), LHSI->getOperand(0),
- ConstantInt::get(ICI.getContext(), NewRHS));
+ Builder->getInt(NewRHS));
}
}
break;
- case Instruction::Xor: // (icmp pred (xor X, XorCST), CI)
- if (ConstantInt *XorCST = dyn_cast<ConstantInt>(LHSI->getOperand(1))) {
+ case Instruction::Xor: // (icmp pred (xor X, XorCst), CI)
+ if (ConstantInt *XorCst = dyn_cast<ConstantInt>(LHSI->getOperand(1))) {
// If this is a comparison that tests the signbit (X < 0) or (x > -1),
// fold the xor.
if ((ICI.getPredicate() == ICmpInst::ICMP_SLT && RHSV == 0) ||
(ICI.getPredicate() == ICmpInst::ICMP_SGT && RHSV.isAllOnesValue())) {
Value *CompareVal = LHSI->getOperand(0);
- // If the sign bit of the XorCST is not set, there is no change to
+ // If the sign bit of the XorCst is not set, there is no change to
// the operation, just stop using the Xor.
- if (!XorCST->isNegative()) {
+ if (!XorCst->isNegative()) {
ICI.setOperand(0, CompareVal);
Worklist.Add(LHSI);
return &ICI;
if (LHSI->hasOneUse()) {
// (icmp u/s (xor A SignBit), C) -> (icmp s/u A, (xor C SignBit))
- if (!ICI.isEquality() && XorCST->getValue().isSignBit()) {
- const APInt &SignBit = XorCST->getValue();
+ if (!ICI.isEquality() && XorCst->getValue().isSignBit()) {
+ const APInt &SignBit = XorCst->getValue();
ICmpInst::Predicate Pred = ICI.isSigned()
? ICI.getUnsignedPredicate()
: ICI.getSignedPredicate();
return new ICmpInst(Pred, LHSI->getOperand(0),
- ConstantInt::get(ICI.getContext(),
- RHSV ^ SignBit));
+ Builder->getInt(RHSV ^ SignBit));
}
// (icmp u/s (xor A ~SignBit), C) -> (icmp s/u (xor C ~SignBit), A)
- if (!ICI.isEquality() && XorCST->isMaxValue(true)) {
- const APInt &NotSignBit = XorCST->getValue();
+ if (!ICI.isEquality() && XorCst->isMaxValue(true)) {
+ const APInt &NotSignBit = XorCst->getValue();
ICmpInst::Predicate Pred = ICI.isSigned()
? ICI.getUnsignedPredicate()
: ICI.getSignedPredicate();
Pred = ICI.getSwappedPredicate(Pred);
return new ICmpInst(Pred, LHSI->getOperand(0),
- ConstantInt::get(ICI.getContext(),
- RHSV ^ NotSignBit));
+ Builder->getInt(RHSV ^ NotSignBit));
}
}
+
+ // (icmp ugt (xor X, C), ~C) -> (icmp ult X, C)
+ // iff -C is a power of 2
+ if (ICI.getPredicate() == ICmpInst::ICMP_UGT &&
+ XorCst->getValue() == ~RHSV && (RHSV + 1).isPowerOf2())
+ return new ICmpInst(ICmpInst::ICMP_ULT, LHSI->getOperand(0), XorCst);
+
+ // (icmp ult (xor X, C), -C) -> (icmp uge X, C)
+ // iff -C is a power of 2
+ if (ICI.getPredicate() == ICmpInst::ICMP_ULT &&
+ XorCst->getValue() == -RHSV && RHSV.isPowerOf2())
+ return new ICmpInst(ICmpInst::ICMP_UGE, LHSI->getOperand(0), XorCst);
}
break;
- case Instruction::And: // (icmp pred (and X, AndCST), RHS)
+ case Instruction::And: // (icmp pred (and X, AndCst), RHS)
if (LHSI->hasOneUse() && isa<ConstantInt>(LHSI->getOperand(1)) &&
LHSI->getOperand(0)->hasOneUse()) {
- ConstantInt *AndCST = cast<ConstantInt>(LHSI->getOperand(1));
+ ConstantInt *AndCst = cast<ConstantInt>(LHSI->getOperand(1));
// If the LHS is an AND of a truncating cast, we can widen the
// and/compare to be the input width without changing the value
// Extending a relational comparison when we're checking the sign
// bit would not work.
if (ICI.isEquality() ||
- (!AndCST->isNegative() && RHSV.isNonNegative())) {
+ (!AndCst->isNegative() && RHSV.isNonNegative())) {
Value *NewAnd =
Builder->CreateAnd(Cast->getOperand(0),
- ConstantExpr::getZExt(AndCST, Cast->getSrcTy()));
+ ConstantExpr::getZExt(AndCst, Cast->getSrcTy()));
NewAnd->takeName(LHSI);
return new ICmpInst(ICI.getPredicate(), NewAnd,
ConstantExpr::getZExt(RHS, Cast->getSrcTy()));
if (ICI.isEquality() && RHSV.getActiveBits() <= Ty->getBitWidth()) {
Value *NewAnd =
Builder->CreateAnd(Cast->getOperand(0),
- ConstantExpr::getTrunc(AndCST, Ty));
+ ConstantExpr::getTrunc(AndCst, Ty));
NewAnd->takeName(LHSI);
return new ICmpInst(ICI.getPredicate(), NewAnd,
ConstantExpr::getTrunc(RHS, Ty));
ConstantInt *ShAmt;
ShAmt = Shift ? dyn_cast<ConstantInt>(Shift->getOperand(1)) : 0;
- Type *Ty = Shift ? Shift->getType() : 0; // Type of the shift.
- Type *AndTy = AndCST->getType(); // Type of the and.
- // We can fold this as long as we can't shift unknown bits
- // into the mask. This can only happen with signed shift
- // rights, as they sign-extend.
+ // This seemingly simple opportunity to fold away a shift turns out to
+ // be rather complicated. See PR17827
+ // ( http://llvm.org/bugs/show_bug.cgi?id=17827 ) for details.
if (ShAmt) {
- bool CanFold = Shift->isLogicalShift();
- if (!CanFold) {
- // To test for the bad case of the signed shr, see if any
- // of the bits shifted in could be tested after the mask.
- uint32_t TyBits = Ty->getPrimitiveSizeInBits();
- int ShAmtVal = TyBits - ShAmt->getLimitedValue(TyBits);
-
- uint32_t BitWidth = AndTy->getPrimitiveSizeInBits();
- if ((APInt::getHighBitsSet(BitWidth, BitWidth-ShAmtVal) &
- AndCST->getValue()) == 0)
+ bool CanFold = false;
+ unsigned ShiftOpcode = Shift->getOpcode();
+ if (ShiftOpcode == Instruction::AShr) {
+ // There may be some constraints that make this possible,
+ // but nothing simple has been discovered yet.
+ CanFold = false;
+ } else if (ShiftOpcode == Instruction::Shl) {
+ // For a left shift, we can fold if the comparison is not signed.
+ // We can also fold a signed comparison if the mask value and
+ // comparison value are not negative. These constraints may not be
+ // obvious, but we can prove that they are correct using an SMT
+ // solver such as "Z3" :
+ // http://rise4fun.com/Z3/DyMp
+ if (!ICI.isSigned() || (!AndCst->isNegative() && !RHS->isNegative()))
+ CanFold = true;
+ } else if (ShiftOpcode == Instruction::LShr) {
+ // For a logical right shift, we can fold if the comparison is not
+ // signed. We can also fold a signed comparison if the shifted mask
+ // value and the shifted comparison value are not negative.
+ // These constraints may not be obvious, but we can prove that they
+ // are correct using an SMT solver such as "Z3" :
+ // http://rise4fun.com/Z3/Tslfh
+ if (!ICI.isSigned())
CanFold = true;
+ else {
+ ConstantInt *ShiftedAndCst =
+ cast<ConstantInt>(ConstantExpr::getShl(AndCst, ShAmt));
+ ConstantInt *ShiftedRHSCst =
+ cast<ConstantInt>(ConstantExpr::getShl(RHS, ShAmt));
+
+ if (!ShiftedAndCst->isNegative() && !ShiftedRHSCst->isNegative())
+ CanFold = true;
+ }
}
if (CanFold) {
Constant *NewCst;
- if (Shift->getOpcode() == Instruction::Shl)
+ if (ShiftOpcode == Instruction::Shl)
NewCst = ConstantExpr::getLShr(RHS, ShAmt);
else
NewCst = ConstantExpr::getShl(RHS, ShAmt);
// Check to see if we are shifting out any of the bits being
// compared.
- if (ConstantExpr::get(Shift->getOpcode(),
- NewCst, ShAmt) != RHS) {
+ if (ConstantExpr::get(ShiftOpcode, NewCst, ShAmt) != RHS) {
// If we shifted bits out, the fold is not going to work out.
// As a special case, check to see if this means that the
// result is always true or false now.
if (ICI.getPredicate() == ICmpInst::ICMP_EQ)
- return ReplaceInstUsesWith(ICI,
- ConstantInt::getFalse(ICI.getContext()));
+ return ReplaceInstUsesWith(ICI, Builder->getFalse());
if (ICI.getPredicate() == ICmpInst::ICMP_NE)
- return ReplaceInstUsesWith(ICI,
- ConstantInt::getTrue(ICI.getContext()));
+ return ReplaceInstUsesWith(ICI, Builder->getTrue());
} else {
ICI.setOperand(1, NewCst);
- Constant *NewAndCST;
- if (Shift->getOpcode() == Instruction::Shl)
- NewAndCST = ConstantExpr::getLShr(AndCST, ShAmt);
+ Constant *NewAndCst;
+ if (ShiftOpcode == Instruction::Shl)
+ NewAndCst = ConstantExpr::getLShr(AndCst, ShAmt);
else
- NewAndCST = ConstantExpr::getShl(AndCST, ShAmt);
- LHSI->setOperand(1, NewAndCST);
+ NewAndCst = ConstantExpr::getShl(AndCst, ShAmt);
+ LHSI->setOperand(1, NewAndCst);
LHSI->setOperand(0, Shift->getOperand(0));
Worklist.Add(Shift); // Shift is dead.
return &ICI;
// Compute C << Y.
Value *NS;
if (Shift->getOpcode() == Instruction::LShr) {
- NS = Builder->CreateShl(AndCST, Shift->getOperand(1));
+ NS = Builder->CreateShl(AndCst, Shift->getOperand(1));
} else {
// Insert a logical shift.
- NS = Builder->CreateLShr(AndCST, Shift->getOperand(1));
+ NS = Builder->CreateLShr(AndCst, Shift->getOperand(1));
}
// Compute X & (C << Y).
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 NTZ = AndCst->getValue().countTrailingZeros();
+ if ((NTZ < AndCst->getBitWidth()) &&
+ APInt::getOneBitSet(AndCst->getBitWidth(), NTZ).ugt(RHSV))
+ return new ICmpInst(ICmpInst::ICMP_NE, LHSI,
+ Constant::getNullValue(RHS->getType()));
+ }
}
// Try to optimize things like "A[i]&42 == 0" to index computations.
return Res;
}
}
+
+ // X & -C == -C -> X > u ~C
+ // X & -C != -C -> X <= u ~C
+ // iff C is a power of 2
+ if (ICI.isEquality() && RHS == LHSI->getOperand(1) && (-RHSV).isPowerOf2())
+ return new ICmpInst(
+ ICI.getPredicate() == ICmpInst::ICMP_EQ ? ICmpInst::ICMP_UGT
+ : ICmpInst::ICMP_ULE,
+ LHSI->getOperand(0), SubOne(RHS));
break;
case Instruction::Or: {
break;
}
+ case Instruction::Mul: { // (icmp pred (mul X, Val), CI)
+ ConstantInt *Val = dyn_cast<ConstantInt>(LHSI->getOperand(1));
+ if (!Val) break;
+
+ // If this is a signed comparison to 0 and the mul is sign preserving,
+ // use the mul LHS operand instead.
+ ICmpInst::Predicate pred = ICI.getPredicate();
+ if (isSignTest(pred, RHS) && !Val->isZero() &&
+ cast<BinaryOperator>(LHSI)->hasNoSignedWrap())
+ return new ICmpInst(Val->isNegative() ?
+ ICmpInst::getSwappedPredicate(pred) : pred,
+ LHSI->getOperand(0),
+ Constant::getNullValue(RHS->getType()));
+
+ break;
+ }
+
case Instruction::Shl: { // (icmp pred (shl X, ShAmt), CI)
+ uint32_t TypeBits = RHSV.getBitWidth();
ConstantInt *ShAmt = dyn_cast<ConstantInt>(LHSI->getOperand(1));
- if (!ShAmt) break;
+ if (!ShAmt) {
+ Value *X;
+ // (1 << X) pred P2 -> X pred Log2(P2)
+ if (match(LHSI, m_Shl(m_One(), m_Value(X)))) {
+ bool RHSVIsPowerOf2 = RHSV.isPowerOf2();
+ ICmpInst::Predicate Pred = ICI.getPredicate();
+ if (ICI.isUnsigned()) {
+ if (!RHSVIsPowerOf2) {
+ // (1 << X) < 30 -> X <= 4
+ // (1 << X) <= 30 -> X <= 4
+ // (1 << X) >= 30 -> X > 4
+ // (1 << X) > 30 -> X > 4
+ if (Pred == ICmpInst::ICMP_ULT)
+ Pred = ICmpInst::ICMP_ULE;
+ else if (Pred == ICmpInst::ICMP_UGE)
+ Pred = 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;
+ }
- uint32_t TypeBits = RHSV.getBitWidth();
+ return new ICmpInst(Pred, X,
+ ConstantInt::get(RHS->getType(), RHSLog2));
+ } else if (ICI.isSigned()) {
+ if (RHSV.isAllOnesValue()) {
+ // (1 << X) <= -1 -> X == 31
+ if (Pred == ICmpInst::ICMP_SLE)
+ return new ICmpInst(ICmpInst::ICMP_EQ, X,
+ ConstantInt::get(RHS->getType(), TypeBits-1));
+
+ // (1 << X) > -1 -> X != 31
+ if (Pred == ICmpInst::ICMP_SGT)
+ return new ICmpInst(ICmpInst::ICMP_NE, X,
+ ConstantInt::get(RHS->getType(), TypeBits-1));
+ } else if (!RHSV) {
+ // (1 << X) < 0 -> X == 31
+ // (1 << X) <= 0 -> X == 31
+ if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE)
+ return new ICmpInst(ICmpInst::ICMP_EQ, X,
+ ConstantInt::get(RHS->getType(), TypeBits-1));
+
+ // (1 << X) >= 0 -> X != 31
+ // (1 << X) > 0 -> X != 31
+ if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE)
+ return new ICmpInst(ICmpInst::ICMP_NE, X,
+ ConstantInt::get(RHS->getType(), TypeBits-1));
+ }
+ } else if (ICI.isEquality()) {
+ 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;
+ }
// Check that the shift amount is in range. If not, don't perform
// undefined shifts. When the shift is visited it will be
ShAmt);
if (Comp != RHS) {// Comparing against a bit that we know is zero.
bool IsICMP_NE = ICI.getPredicate() == ICmpInst::ICMP_NE;
- Constant *Cst =
- ConstantInt::get(Type::getInt1Ty(ICI.getContext()), IsICMP_NE);
+ Constant *Cst = Builder->getInt1(IsICMP_NE);
return ReplaceInstUsesWith(ICI, Cst);
}
return new ICmpInst(ICI.getPredicate(), LHSI->getOperand(0),
ConstantExpr::getLShr(RHS, ShAmt));
+ // If the shift is NSW and we compare to 0, then it is just shifting out
+ // sign bits, no need for an AND either.
+ if (cast<BinaryOperator>(LHSI)->hasNoSignedWrap() && RHSV == 0)
+ return new ICmpInst(ICI.getPredicate(), LHSI->getOperand(0),
+ ConstantExpr::getLShr(RHS, ShAmt));
+
if (LHSI->hasOneUse()) {
// Otherwise strength reduce the shift into an and.
uint32_t ShAmtVal = (uint32_t)ShAmt->getLimitedValue(TypeBits);
- Constant *Mask =
- ConstantInt::get(ICI.getContext(), APInt::getLowBitsSet(TypeBits,
- TypeBits-ShAmtVal));
+ Constant *Mask = Builder->getInt(APInt::getLowBitsSet(TypeBits,
+ TypeBits - ShAmtVal));
Value *And =
Builder->CreateAnd(LHSI->getOperand(0),Mask, LHSI->getName()+".mask");
}
}
+ // If this is a signed comparison to 0 and the shift is sign preserving,
+ // use the shift LHS operand instead.
+ ICmpInst::Predicate pred = ICI.getPredicate();
+ if (isSignTest(pred, RHS) &&
+ cast<BinaryOperator>(LHSI)->hasNoSignedWrap())
+ return new ICmpInst(pred,
+ LHSI->getOperand(0),
+ Constant::getNullValue(RHS->getType()));
+
// Otherwise, if this is a comparison of the sign bit, simplify to and/test.
bool TrueIfSigned = false;
if (LHSI->hasOneUse() &&
return new ICmpInst(TrueIfSigned ? ICmpInst::ICMP_NE : ICmpInst::ICMP_EQ,
And, Constant::getNullValue(And->getType()));
}
+
+ // Transform (icmp pred iM (shl iM %v, N), CI)
+ // -> (icmp pred i(M-N) (trunc %v iM to i(M-N)), (trunc (CI>>N))
+ // Transform the shl to a trunc if (trunc (CI>>N)) has no loss and M-N.
+ // This enables to get rid of the shift in favor of a trunc which can be
+ // free on the target. It has the additional benefit of comparing to a
+ // smaller constant, which will be target friendly.
+ unsigned Amt = ShAmt->getLimitedValue(TypeBits-1);
+ if (LHSI->hasOneUse() &&
+ Amt != 0 && RHSV.countTrailingZeros() >= Amt) {
+ Type *NTy = IntegerType::get(ICI.getContext(), TypeBits - Amt);
+ Constant *NCI = ConstantExpr::getTrunc(
+ ConstantExpr::getAShr(RHS,
+ ConstantInt::get(RHS->getType(), Amt)),
+ NTy);
+ return new ICmpInst(ICI.getPredicate(),
+ Builder->CreateTrunc(LHSI->getOperand(0), NTy),
+ NCI);
+ }
+
break;
}
return R;
break;
+ case Instruction::Sub: {
+ ConstantInt *LHSC = dyn_cast<ConstantInt>(LHSI->getOperand(0));
+ if (!LHSC) break;
+ const APInt &LHSV = LHSC->getValue();
+
+ // C1-X <u C2 -> (X|(C2-1)) == C1
+ // iff C1 & (C2-1) == C2-1
+ // C2 is a power of 2
+ if (ICI.getPredicate() == ICmpInst::ICMP_ULT && LHSI->hasOneUse() &&
+ RHSV.isPowerOf2() && (LHSV & (RHSV - 1)) == (RHSV - 1))
+ return new ICmpInst(ICmpInst::ICMP_EQ,
+ Builder->CreateOr(LHSI->getOperand(1), RHSV - 1),
+ LHSC);
+
+ // C1-X >u C2 -> (X|C2) != C1
+ // iff C1 & C2 == C2
+ // C2+1 is a power of 2
+ if (ICI.getPredicate() == ICmpInst::ICMP_UGT && LHSI->hasOneUse() &&
+ (RHSV + 1).isPowerOf2() && (LHSV & RHSV) == RHSV)
+ return new ICmpInst(ICmpInst::ICMP_NE,
+ Builder->CreateOr(LHSI->getOperand(1), RHSV), LHSC);
+ break;
+ }
+
case Instruction::Add:
// Fold: icmp pred (add X, C1), C2
if (!ICI.isEquality()) {
if (ICI.isSigned()) {
if (CR.getLower().isSignBit()) {
return new ICmpInst(ICmpInst::ICMP_SLT, LHSI->getOperand(0),
- ConstantInt::get(ICI.getContext(),CR.getUpper()));
+ Builder->getInt(CR.getUpper()));
} else if (CR.getUpper().isSignBit()) {
return new ICmpInst(ICmpInst::ICMP_SGE, LHSI->getOperand(0),
- ConstantInt::get(ICI.getContext(),CR.getLower()));
+ Builder->getInt(CR.getLower()));
}
} else {
if (CR.getLower().isMinValue()) {
return new ICmpInst(ICmpInst::ICMP_ULT, LHSI->getOperand(0),
- ConstantInt::get(ICI.getContext(),CR.getUpper()));
+ Builder->getInt(CR.getUpper()));
} else if (CR.getUpper().isMinValue()) {
return new ICmpInst(ICmpInst::ICMP_UGE, LHSI->getOperand(0),
- ConstantInt::get(ICI.getContext(),CR.getLower()));
+ Builder->getInt(CR.getLower()));
}
}
+
+ // X-C1 <u C2 -> (X & -C2) == C1
+ // iff C1 & (C2-1) == 0
+ // C2 is a power of 2
+ if (ICI.getPredicate() == ICmpInst::ICMP_ULT && LHSI->hasOneUse() &&
+ RHSV.isPowerOf2() && (LHSV & (RHSV - 1)) == 0)
+ return new ICmpInst(ICmpInst::ICMP_EQ,
+ Builder->CreateAnd(LHSI->getOperand(0), -RHSV),
+ ConstantExpr::getNeg(LHSC));
+
+ // X-C1 >u C2 -> (X & ~C2) != C1
+ // iff C1 & C2 == 0
+ // C2+1 is a power of 2
+ if (ICI.getPredicate() == ICmpInst::ICMP_UGT && LHSI->hasOneUse() &&
+ (RHSV + 1).isPowerOf2() && (LHSV & RHSV) == 0)
+ return new ICmpInst(ICmpInst::ICMP_NE,
+ Builder->CreateAnd(LHSI->getOperand(0), ~RHSV),
+ ConstantExpr::getNeg(LHSC));
}
break;
}
if (ConstantInt *BOC = dyn_cast<ConstantInt>(BO->getOperand(1))) {
Constant *NotCI = ConstantExpr::getNot(RHS);
if (!ConstantExpr::getAnd(BOC, NotCI)->isNullValue())
- return ReplaceInstUsesWith(ICI,
- ConstantInt::get(Type::getInt1Ty(ICI.getContext()),
- isICMP_NE));
+ return ReplaceInstUsesWith(ICI, Builder->getInt1(isICMP_NE));
}
break;
// If bits are being compared against that are and'd out, then the
// comparison can never succeed!
if ((RHSV & ~BOC->getValue()) != 0)
- return ReplaceInstUsesWith(ICI,
- ConstantInt::get(Type::getInt1Ty(ICI.getContext()),
- isICMP_NE));
+ return ReplaceInstUsesWith(ICI, Builder->getInt1(isICMP_NE));
// If we have ((X & C) == C), turn it into ((X & C) != 0).
if (RHS == BOC && RHSV.isPowerOf2())
return new ICmpInst(pred, X, NegX);
}
}
+ break;
+ case Instruction::Mul:
+ if (RHSV == 0 && BO->hasNoSignedWrap()) {
+ if (ConstantInt *BOC = dyn_cast<ConstantInt>(BO->getOperand(1))) {
+ // The trivial case (mul X, 0) is handled by InstSimplify
+ // General case : (mul X, C) != 0 iff X != 0
+ // (mul X, C) == 0 iff X == 0
+ if (!BOC->isZero())
+ return new ICmpInst(ICI.getPredicate(), BO->getOperand(0),
+ Constant::getNullValue(RHS->getType()));
+ }
+ }
+ break;
default: break;
}
} else if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(LHSI)) {
case Intrinsic::bswap:
Worklist.Add(II);
ICI.setOperand(0, II->getArgOperand(0));
- ICI.setOperand(1, ConstantInt::get(II->getContext(), RHSV.byteSwap()));
+ ICI.setOperand(1, Builder->getInt(RHSV.byteSwap()));
return &ICI;
case Intrinsic::ctlz:
case Intrinsic::cttz:
// 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->getPointerSizeInBits() ==
- cast<IntegerType>(DestTy)->getBitWidth()) {
+ TD->getPointerTypeSizeInBits(SrcTy) == DestTy->getIntegerBitWidth()) {
Value *RHSOp = 0;
if (Constant *RHSC = dyn_cast<Constant>(ICI.getOperand(1))) {
RHSOp = ConstantExpr::getIntToPtr(RHSC, SrcTy);
}
+/// \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
+/// 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
+/// match.
+/// \return true if Op0 and Op1 should be swapped.
+static bool swapMayExposeCSEOpportunities(const Value * Op0,
+ const Value * Op1) {
+ // Filter out pointer value as those cannot appears directly in subtract.
+ // FIXME: we may want to go through inttoptrs or bitcasts.
+ if (Op0->getType()->isPointerTy())
+ return false;
+ // Count every uses of both Op0 and Op1 in a subtract.
+ // 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.
+ // 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);
+ if (!BinOp || BinOp->getOpcode() != Instruction::Sub)
+ continue;
+ // If Op0 is the first argument, this is not beneficial to swap the
+ // arguments.
+ int LocalSwapBenefits = -1;
+ unsigned Op1Idx = 1;
+ if (BinOp->getOperand(Op1Idx) == Op0) {
+ Op1Idx = 0;
+ LocalSwapBenefits = 1;
+ }
+ if (BinOp->getOperand(Op1Idx) != Op1)
+ continue;
+ GlobalSwapBenefits += LocalSwapBenefits;
+ }
+ return GlobalSwapBenefits > 0;
+}
+
Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
bool Changed = false;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ unsigned Op0Cplxity = getComplexity(Op0);
+ unsigned Op1Cplxity = getComplexity(Op1);
/// Orders the operands of the compare so that they are listed from most
/// complex to least complex. This puts constants before unary operators,
/// before binary operators.
- if (getComplexity(Op0) < getComplexity(Op1)) {
+ if (Op0Cplxity < Op1Cplxity ||
+ (Op0Cplxity == Op1Cplxity &&
+ swapMayExposeCSEOpportunities(Op0, Op1))) {
I.swapOperands();
std::swap(Op0, Op1);
Changed = true;
case ICmpInst::ICMP_ULE:
assert(!CI->isMaxValue(false)); // A <=u MAX -> TRUE
return new ICmpInst(ICmpInst::ICMP_ULT, Op0,
- ConstantInt::get(CI->getContext(), CI->getValue()+1));
+ Builder->getInt(CI->getValue()+1));
case ICmpInst::ICMP_SLE:
assert(!CI->isMaxValue(true)); // A <=s MAX -> TRUE
return new ICmpInst(ICmpInst::ICMP_SLT, Op0,
- ConstantInt::get(CI->getContext(), CI->getValue()+1));
+ Builder->getInt(CI->getValue()+1));
case ICmpInst::ICMP_UGE:
assert(!CI->isMinValue(false)); // A >=u MIN -> TRUE
return new ICmpInst(ICmpInst::ICMP_UGT, Op0,
- ConstantInt::get(CI->getContext(), CI->getValue()-1));
+ Builder->getInt(CI->getValue()-1));
case ICmpInst::ICMP_SGE:
assert(!CI->isMinValue(true)); // A >=s MIN -> TRUE
return new ICmpInst(ICmpInst::ICMP_SGT, Op0,
- ConstantInt::get(CI->getContext(), CI->getValue()-1));
+ Builder->getInt(CI->getValue()-1));
}
// If this comparison is a normal comparison, it demands all
CI->countTrailingZeros()));
}
- // Turn x&~y == 0 into x&y != 0 if x is a power of 2.
- Value *X = 0, *Y = 0;
- if (match(Op0, m_And(m_Value(X), m_Not(m_Value(Y)))) &&
- match(Op1, m_Zero()) && isPowerOfTwo(X, TD)) {
- return new ICmpInst(ICmpInst::ICMP_NE,
- Builder->CreateAnd(X, Y),
- Op1);
- }
-
break;
}
case ICmpInst::ICMP_NE: {
CI->countTrailingZeros()));
}
- // Turn x&~y != 0 into x&y == 0 if x is a power of 2.
- Value *X = 0, *Y = 0;
- if (match(Op0, m_And(m_Value(X), m_Not(m_Value(Y)))) &&
- match(Op1, m_Zero()) && isPowerOfTwo(X, TD)) {
- return new ICmpInst(ICmpInst::ICMP_EQ,
- Builder->CreateAnd(X, Y),
- Op1);
- }
-
break;
}
case ICmpInst::ICMP_ULT:
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
if (Op1Max == Op0Min+1) // A <u C -> A == C-1 if min(A)+1 == C
return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
- ConstantInt::get(CI->getContext(), CI->getValue()-1));
+ Builder->getInt(CI->getValue()-1));
// (x <u 2147483648) -> (x >s -1) -> true if sign bit clear
if (CI->isMinValue(true))
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
if (Op1Min == Op0Max-1) // A >u C -> A == C+1 if max(a)-1 == C
return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
- ConstantInt::get(CI->getContext(), CI->getValue()+1));
+ Builder->getInt(CI->getValue()+1));
// (x >u 2147483647) -> (x <s 0) -> true if sign bit set
if (CI->isMaxValue(true))
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
if (Op1Max == Op0Min+1) // A <s C -> A == C-1 if min(A)+1 == C
return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
- ConstantInt::get(CI->getContext(), CI->getValue()-1));
+ Builder->getInt(CI->getValue()-1));
}
break;
case ICmpInst::ICMP_SGT:
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
if (Op1Min == Op0Max-1) // A >s C -> A == C+1 if max(A)-1 == C
return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
- ConstantInt::get(CI->getContext(), CI->getValue()+1));
+ Builder->getInt(CI->getValue()+1));
}
break;
case ICmpInst::ICMP_SGE:
case Instruction::IntToPtr:
// icmp pred inttoptr(X), null -> icmp pred X, 0
if (RHSC->isNullValue() && TD &&
- TD->getIntPtrType(RHSC->getContext()) ==
+ TD->getIntPtrType(RHSC->getType()) ==
LHSI->getOperand(0)->getType())
return new ICmpInst(I.getPredicate(), LHSI->getOperand(0),
Constant::getNullValue(LHSI->getOperand(0)->getType()));
return new ICmpInst(Pred, Y, Z);
}
+ // icmp slt (X + -1), Y -> icmp sle X, Y
+ if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SLT &&
+ match(B, m_AllOnes()))
+ return new ICmpInst(CmpInst::ICMP_SLE, A, Op1);
+
+ // icmp sge (X + -1), Y -> icmp sgt X, Y
+ if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SGE &&
+ match(B, m_AllOnes()))
+ return new ICmpInst(CmpInst::ICMP_SGT, A, Op1);
+
+ // icmp sle (X + 1), Y -> icmp slt X, Y
+ if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SLE &&
+ match(B, m_One()))
+ return new ICmpInst(CmpInst::ICMP_SLT, A, Op1);
+
+ // icmp sgt (X + 1), Y -> icmp sge X, Y
+ if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SGT &&
+ match(B, m_One()))
+ return new ICmpInst(CmpInst::ICMP_SGE, A, Op1);
+
+ // if C1 has greater magnitude than C2:
+ // icmp (X + C1), (Y + C2) -> icmp (X + C3), Y
+ // s.t. C3 = C1 - C2
+ //
+ // if C2 has greater magnitude than C1:
+ // icmp (X + C1), (Y + C2) -> icmp X, (Y + C3)
+ // s.t. C3 = C2 - C1
+ if (A && C && NoOp0WrapProblem && NoOp1WrapProblem &&
+ (BO0->hasOneUse() || BO1->hasOneUse()) && !I.isUnsigned())
+ if (ConstantInt *C1 = dyn_cast<ConstantInt>(B))
+ if (ConstantInt *C2 = dyn_cast<ConstantInt>(D)) {
+ const APInt &AP1 = C1->getValue();
+ const APInt &AP2 = C2->getValue();
+ if (AP1.isNegative() == AP2.isNegative()) {
+ APInt AP1Abs = C1->getValue().abs();
+ APInt AP2Abs = C2->getValue().abs();
+ if (AP1Abs.uge(AP2Abs)) {
+ ConstantInt *C3 = Builder->getInt(AP1 - AP2);
+ Value *NewAdd = Builder->CreateNSWAdd(A, C3);
+ return new ICmpInst(Pred, NewAdd, C);
+ } else {
+ ConstantInt *C3 = Builder->getInt(AP2 - AP1);
+ Value *NewAdd = Builder->CreateNSWAdd(C, C3);
+ return new ICmpInst(Pred, A, NewAdd);
+ }
+ }
+ }
+
+
// 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;
}
{ Value *A, *B;
+ // Transform (A & ~B) == 0 --> (A & B) != 0
+ // 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())
+ return new ICmpInst(I.getInversePredicate(),
+ Builder->CreateAnd(A, B),
+ Op1);
+
// ~x < ~y --> y < x
// ~x < cst --> ~cst < x
if (match(Op0, m_Not(m_Value(A)))) {
ConstantInt *C1, *C2;
if (match(B, m_ConstantInt(C1)) &&
match(D, m_ConstantInt(C2)) && Op1->hasOneUse()) {
- Constant *NC = ConstantInt::get(I.getContext(),
- C1->getValue() ^ C2->getValue());
+ Constant *NC = Builder->getInt(C1->getValue() ^ C2->getValue());
Value *Xor = Builder->CreateXor(C, NC);
return new ICmpInst(I.getPredicate(), A, Xor);
}
Builder->CreateTrunc(B, A->getType()));
}
+ // (A >> C) == (B >> C) --> (A^B) u< (1 << C)
+ // For lshr and ashr pairs.
+ if ((match(Op0, m_OneUse(m_LShr(m_Value(A), m_ConstantInt(Cst1)))) &&
+ match(Op1, m_OneUse(m_LShr(m_Value(B), m_Specific(Cst1))))) ||
+ (match(Op0, m_OneUse(m_AShr(m_Value(A), m_ConstantInt(Cst1)))) &&
+ match(Op1, m_OneUse(m_AShr(m_Value(B), m_Specific(Cst1)))))) {
+ unsigned TypeBits = Cst1->getBitWidth();
+ unsigned ShAmt = (unsigned)Cst1->getLimitedValue(TypeBits);
+ if (ShAmt < TypeBits && ShAmt != 0) {
+ ICmpInst::Predicate Pred = I.getPredicate() == ICmpInst::ICMP_NE
+ ? ICmpInst::ICMP_UGE
+ : ICmpInst::ICMP_ULT;
+ Value *Xor = Builder->CreateXor(A, B, I.getName() + ".unshifted");
+ APInt CmpVal = APInt::getOneBitSet(TypeBits, ShAmt);
+ return new ICmpInst(Pred, Xor, Builder->getInt(CmpVal));
+ }
+ }
+
// Transform "icmp eq (trunc (lshr(X, cst1)), cst" to
// "icmp (and X, mask), cst"
uint64_t ShAmt = 0;
Value *X; ConstantInt *Cst;
// icmp X+Cst, X
if (match(Op0, m_Add(m_Value(X), m_ConstantInt(Cst))) && Op1 == X)
- return FoldICmpAddOpCst(I, X, Cst, I.getPredicate(), Op0);
+ return FoldICmpAddOpCst(I, X, Cst, I.getPredicate());
// icmp X, X+Cst
if (match(Op1, m_Add(m_Value(X), m_ConstantInt(Cst))) && Op0 == X)
- return FoldICmpAddOpCst(I, X, Cst, I.getSwappedPredicate(), Op1);
+ return FoldICmpAddOpCst(I, X, Cst, I.getSwappedPredicate());
}
return Changed ? &I : 0;
}
-
-
-
-
-
/// FoldFCmp_IntToFP_Cst - Fold fcmp ([us]itofp x, cst) if possible.
///
Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I,
Pred = ICmpInst::ICMP_NE;
break;
case FCmpInst::FCMP_ORD:
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getTrue());
case FCmpInst::FCMP_UNO:
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getFalse());
}
IntegerType *IntTy = cast<IntegerType>(LHSI->getOperand(0)->getType());
if (!LHSUnsigned) {
// If the RHS value is > SignedMax, fold the comparison. This handles +INF
// and large values.
- APFloat SMax(RHS.getSemantics(), APFloat::fcZero, false);
+ APFloat SMax(RHS.getSemantics());
SMax.convertFromAPInt(APInt::getSignedMaxValue(IntWidth), true,
APFloat::rmNearestTiesToEven);
if (SMax.compare(RHS) == APFloat::cmpLessThan) { // smax < 13123.0
if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SLT ||
Pred == ICmpInst::ICMP_SLE)
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getTrue());
+ return ReplaceInstUsesWith(I, Builder->getFalse());
}
} else {
// If the RHS value is > UnsignedMax, fold the comparison. This handles
// +INF and large values.
- APFloat UMax(RHS.getSemantics(), APFloat::fcZero, false);
+ APFloat UMax(RHS.getSemantics());
UMax.convertFromAPInt(APInt::getMaxValue(IntWidth), false,
APFloat::rmNearestTiesToEven);
if (UMax.compare(RHS) == APFloat::cmpLessThan) { // umax < 13123.0
if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_ULT ||
Pred == ICmpInst::ICMP_ULE)
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getTrue());
+ return ReplaceInstUsesWith(I, Builder->getFalse());
}
}
if (!LHSUnsigned) {
// See if the RHS value is < SignedMin.
- APFloat SMin(RHS.getSemantics(), APFloat::fcZero, false);
+ APFloat SMin(RHS.getSemantics());
SMin.convertFromAPInt(APInt::getSignedMinValue(IntWidth), true,
APFloat::rmNearestTiesToEven);
if (SMin.compare(RHS) == APFloat::cmpGreaterThan) { // smin > 12312.0
if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SGT ||
Pred == ICmpInst::ICMP_SGE)
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getTrue());
+ return ReplaceInstUsesWith(I, Builder->getFalse());
}
} else {
// See if the RHS value is < UnsignedMin.
- APFloat SMin(RHS.getSemantics(), APFloat::fcZero, false);
+ APFloat SMin(RHS.getSemantics());
SMin.convertFromAPInt(APInt::getMinValue(IntWidth), true,
APFloat::rmNearestTiesToEven);
if (SMin.compare(RHS) == APFloat::cmpGreaterThan) { // umin > 12312.0
if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_UGT ||
Pred == ICmpInst::ICMP_UGE)
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getTrue());
+ return ReplaceInstUsesWith(I, Builder->getFalse());
}
}
switch (Pred) {
default: llvm_unreachable("Unexpected integer comparison!");
case ICmpInst::ICMP_NE: // (float)int != 4.4 --> true
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getTrue());
case ICmpInst::ICMP_EQ: // (float)int == 4.4 --> false
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getFalse());
case ICmpInst::ICMP_ULE:
// (float)int <= 4.4 --> int <= 4
// (float)int <= -4.4 --> false
if (RHS.isNegative())
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getFalse());
break;
case ICmpInst::ICMP_SLE:
// (float)int <= 4.4 --> int <= 4
// (float)int < -4.4 --> false
// (float)int < 4.4 --> int <= 4
if (RHS.isNegative())
- return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getFalse());
Pred = ICmpInst::ICMP_ULE;
break;
case ICmpInst::ICMP_SLT:
// (float)int > 4.4 --> int > 4
// (float)int > -4.4 --> true
if (RHS.isNegative())
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getTrue());
break;
case ICmpInst::ICMP_SGT:
// (float)int > 4.4 --> int > 4
// (float)int >= -4.4 --> true
// (float)int >= 4.4 --> int > 4
if (RHS.isNegative())
- return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
+ return ReplaceInstUsesWith(I, Builder->getTrue());
Pred = ICmpInst::ICMP_UGT;
break;
case ICmpInst::ICMP_SGE:
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