diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 9625398017..385c07004d 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -343,17 +343,31 @@ Instruction *InstCombiner::visitXor(BinaryOperator *I) { return Changed ? I : 0; } +// isTrueWhenEqual - Return true if the specified setcondinst instruction is +// true when both operands are equal... +// +static bool isTrueWhenEqual(Instruction *I) { + return I->getOpcode() == Instruction::SetEQ || + I->getOpcode() == Instruction::SetGE || + I->getOpcode() == Instruction::SetLE; +} + Instruction *InstCombiner::visitSetCondInst(BinaryOperator *I) { if (I->use_empty()) return 0; // Don't fix dead instructions... bool Changed = SimplifyBinOp(I); // setcc X, X if (I->getOperand(0) == I->getOperand(1)) { - bool NewVal = I->getOpcode() == Instruction::SetEQ || - I->getOpcode() == Instruction::SetGE || - I->getOpcode() == Instruction::SetLE; AddUsesToWorkList(I); // Add all modified instrs to worklist - I->replaceAllUsesWith(ConstantBool::get(NewVal)); + I->replaceAllUsesWith(ConstantBool::get(isTrueWhenEqual(I))); + return I; + } + + // setcc <global*>, 0 - Global value addresses are never null! + if (isa<GlobalValue>(I->getOperand(0)) && + isa<ConstantPointerNull>(I->getOperand(1))) { + AddUsesToWorkList(I); // Add all modified instrs to worklist + I->replaceAllUsesWith(ConstantBool::get(!isTrueWhenEqual(I))); return I; } |