Fix missed optimization opportunity when analyzing cast of mul and select.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53151 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 5d75489..8c3f2d5 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -6917,6 +6917,7 @@
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 @@
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 @@
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 @@
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);