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-rw-r--r--lib/Transforms/Scalar/InstructionCombining.cpp30
1 files changed, 25 insertions, 5 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 33de49d391..d9c6ccee8d 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -697,15 +697,35 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) {
// integers at the end of their ranges...
//
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
- if (CI->isNullValue()) {
- if (I.getOpcode() == Instruction::SetNE)
- return new CastInst(Op0, Type::BoolTy, I.getName());
- else if (I.getOpcode() == Instruction::SetEQ) {
+ // Simplify seteq and setne instructions...
+ if (I.getOpcode() == Instruction::SetEQ ||
+ I.getOpcode() == Instruction::SetNE) {
+ bool isSetNE = I.getOpcode() == Instruction::SetNE;
+
+ if (CI->isNullValue()) { // Simplify [seteq|setne] X, 0
+ CastInst *Val = new CastInst(Op0, Type::BoolTy, I.getName()+".not");
+ if (isSetNE) return Val;
+
// seteq X, 0 -> not (cast X to bool)
- Instruction *Val = new CastInst(Op0, Type::BoolTy, I.getName()+".not");
InsertNewInstBefore(Val, I);
return BinaryOperator::createNot(Val, I.getName());
}
+
+ // If the first operand is (and|or) with a constant, and the second
+ // operand is a constant, simplify a bit.
+ if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0))
+ if (ConstantInt *BOC = dyn_cast<ConstantInt>(BO->getOperand(1)))
+ if (BO->getOpcode() == Instruction::Or) {
+ // If bits are being or'd in that are not present in the constant we
+ // are comparing against, then the comparison could never succeed!
+ if (!(*BOC & *~*CI)->isNullValue())
+ return ReplaceInstUsesWith(I, ConstantBool::get(isSetNE));
+ } else if (BO->getOpcode() == Instruction::And) {
+ // If bits are being compared against that are and'd out, then the
+ // comparison can never succeed!
+ if (!(*CI & *~*BOC)->isNullValue())
+ return ReplaceInstUsesWith(I, ConstantBool::get(isSetNE));
+ }
}
// Check to see if we are comparing against the minimum or maximum value...