diff options
Diffstat (limited to 'llvm/lib/Transforms/Scalar/InstructionCombining.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index bf287f2c680..5bd17e0737b 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -8564,20 +8564,33 @@ Instruction *InstCombiner::visitZExt(ZExtInst &CI) { } } - // zext(trunc(t) & C) -> (t & C) if C is a mask. + // zext(trunc(t) & C) -> (t & zext(C)). if (SrcI && SrcI->getOpcode() == Instruction::And && SrcI->hasOneUse()) if (ConstantInt *C = dyn_cast<ConstantInt>(SrcI->getOperand(1))) if (TruncInst *TI = dyn_cast<TruncInst>(SrcI->getOperand(0))) { Value *TI0 = TI->getOperand(0); - if (TI0->getType() == CI.getType()) { - unsigned TO = C->getValue().countTrailingOnes(); - if (APIntOps::isMask(TO, C->getValue())) - return - BinaryOperator::Create(Instruction::And, TI0, - ConstantExpr::getZExt(C, CI.getType())); - } + if (TI0->getType() == CI.getType()) + return + BinaryOperator::CreateAnd(TI0, + ConstantExpr::getZExt(C, CI.getType())); } + // zext((trunc(t) & C) ^ C) -> ((t & zext(C)) ^ zext(C)). + if (SrcI && SrcI->getOpcode() == Instruction::Xor && SrcI->hasOneUse()) + if (ConstantInt *C = dyn_cast<ConstantInt>(SrcI->getOperand(1))) + if (BinaryOperator *And = dyn_cast<BinaryOperator>(SrcI->getOperand(0))) + if (And->getOpcode() == Instruction::And && And->hasOneUse() && + And->getOperand(1) == C) + if (TruncInst *TI = dyn_cast<TruncInst>(And->getOperand(0))) { + Value *TI0 = TI->getOperand(0); + if (TI0->getType() == CI.getType()) { + Constant *ZC = ConstantExpr::getZExt(C, CI.getType()); + Instruction *NewAnd = BinaryOperator::CreateAnd(TI0, ZC, "tmp"); + InsertNewInstBefore(NewAnd, *And); + return BinaryOperator::CreateXor(NewAnd, ZC); + } + } + return 0; } |
