diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 28 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/compare-signs.ll | 1 |
2 files changed, 1 insertions, 28 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 14a482dd6e..efda6608e4 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -8539,34 +8539,6 @@ Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, Instruction &CI, } } - // icmp ne A, B is equal to xor A, B when A and B only really have one bit. - // It is also profitable to transform icmp eq into not(xor(A, B)) because that - // may lead to additional simplifications. - if (CI.getType() == ICI->getOperand(0)->getType()) { - if (const IntegerType *ITy = dyn_cast<IntegerType>(CI.getType())) { - Value *LHS = ICI->getOperand(0); - Value *RHS = ICI->getOperand(1); - - uint32_t BitWidth = ITy->getBitWidth(); - APInt KnownZeroLHS(BitWidth, 0), KnownOneLHS(BitWidth, 0); - APInt KnownZeroRHS(BitWidth, 0), KnownOneRHS(BitWidth, 0); - APInt TypeMask(APInt::getAllOnesValue(BitWidth)); - ComputeMaskedBits(LHS, TypeMask, KnownZeroLHS, KnownOneLHS); - ComputeMaskedBits(RHS, TypeMask, KnownZeroRHS, KnownOneRHS); - - if (KnownZeroLHS.countLeadingOnes() == BitWidth-1 && - KnownZeroRHS.countLeadingOnes() == BitWidth-1) { - if (!DoXform) return ICI; - - Value *Xor = Builder->CreateXor(LHS, RHS); - if (ICI->isTrueWhenEqual()) - Xor = Builder->CreateXor(Xor, ConstantInt::get(ITy, 1)); - Xor->takeName(ICI); - return ReplaceInstUsesWith(CI, Xor); - } - } - } - return 0; } diff --git a/test/Transforms/InstCombine/compare-signs.ll b/test/Transforms/InstCombine/compare-signs.ll index ba638ba36f..2f98641a24 100644 --- a/test/Transforms/InstCombine/compare-signs.ll +++ b/test/Transforms/InstCombine/compare-signs.ll @@ -1,4 +1,5 @@ ; RUN: opt %s -instcombine -S | FileCheck %s +; XFAIL: * ; PR5438 ; TODO: This should also optimize down. |