diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 23 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/cast-mul-select.ll | 29 |
2 files changed, 43 insertions, 9 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 5d75489d14..8c3f2d5a74 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -6917,6 +6917,7 @@ bool InstCombiner::CanEvaluateInDifferentType(Value *V, const IntegerType *Ty, switch (I->getOpcode()) { case Instruction::Add: case Instruction::Sub: + case Instruction::Mul: case Instruction::And: case Instruction::Or: case Instruction::Xor: @@ -6926,14 +6927,6 @@ bool InstCombiner::CanEvaluateInDifferentType(Value *V, const IntegerType *Ty, CanEvaluateInDifferentType(I->getOperand(1), Ty, CastOpc, NumCastsRemoved); - case Instruction::Mul: - // A multiply can be truncated by truncating its operands. - return Ty->getBitWidth() < OrigTy->getBitWidth() && - CanEvaluateInDifferentType(I->getOperand(0), Ty, CastOpc, - NumCastsRemoved) && - CanEvaluateInDifferentType(I->getOperand(1), Ty, CastOpc, - NumCastsRemoved); - case Instruction::Shl: // If we are truncating the result of this SHL, and if it's a shift of a // constant amount, we can always perform a SHL in a smaller type. @@ -6970,7 +6963,13 @@ bool InstCombiner::CanEvaluateInDifferentType(Value *V, const IntegerType *Ty, if (I->getOpcode() == CastOpc) return true; break; - + case Instruction::Select: { + SelectInst *SI = cast<SelectInst>(I); + return CanEvaluateInDifferentType(SI->getTrueValue(), Ty, CastOpc, + NumCastsRemoved) && + CanEvaluateInDifferentType(SI->getFalseValue(), Ty, CastOpc, + NumCastsRemoved); + } case Instruction::PHI: { // We can change a phi if we can change all operands. PHINode *PN = cast<PHINode>(I); @@ -7028,6 +7027,12 @@ Value *InstCombiner::EvaluateInDifferentType(Value *V, const Type *Ty, Res = CastInst::Create(cast<CastInst>(I)->getOpcode(), I->getOperand(0), Ty); break; + case Instruction::Select: { + Value *True = EvaluateInDifferentType(I->getOperand(1), Ty, isSigned); + Value *False = EvaluateInDifferentType(I->getOperand(2), Ty, isSigned); + Res = SelectInst::Create(I->getOperand(0), True, False); + break; + } case Instruction::PHI: { PHINode *OPN = cast<PHINode>(I); PHINode *NPN = PHINode::Create(Ty); diff --git a/test/Transforms/InstCombine/cast-mul-select.ll b/test/Transforms/InstCombine/cast-mul-select.ll new file mode 100644 index 0000000000..76e9b24332 --- /dev/null +++ b/test/Transforms/InstCombine/cast-mul-select.ll @@ -0,0 +1,29 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | notcast + +define i32 @mul(i32 %x, i32 %y) { + %A = trunc i32 %x to i8 + %B = trunc i32 %y to i8 + %C = mul i8 %A, %B + %D = zext i8 %C to i32 + ret i32 %D +} + +define i32 @select1(i1 %cond, i32 %x, i32 %y, i32 %z) { + %A = trunc i32 %x to i8 + %B = trunc i32 %y to i8 + %C = trunc i32 %z to i8 + %D = add i8 %A, %B + %E = select i1 %cond, i8 %C, i8 %D + %F = zext i8 %E to i32 + ret i32 %F +} + +define i8 @select2(i1 %cond, i8 %x, i8 %y, i8 %z) { + %A = zext i8 %x to i32 + %B = zext i8 %y to i32 + %C = zext i8 %z to i32 + %D = add i32 %A, %B + %E = select i1 %cond, i32 %C, i32 %D + %F = trunc i32 %E to i8 + ret i8 %F +} |