Previously SimplifyInstruction could report that an instruction
simplified to itself (this can only happen in unreachable blocks).
Change it to return null instead. Hopefully this will fix some
buildbot failures.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119490 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index c540d6f..5ad842b 100644
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -756,34 +756,50 @@
/// instruction. If not, this returns null.
Value *llvm::SimplifyInstruction(Instruction *I, const TargetData *TD,
const DominatorTree *DT) {
+ Value *Result;
+
switch (I->getOpcode()) {
default:
- return ConstantFoldInstruction(I, TD);
+ Result = ConstantFoldInstruction(I, TD);
+ break;
case Instruction::Add:
- return SimplifyAddInst(I->getOperand(0), I->getOperand(1),
- cast<BinaryOperator>(I)->hasNoSignedWrap(),
- cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
- TD, DT);
+ Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
+ cast<BinaryOperator>(I)->hasNoSignedWrap(),
+ cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
+ TD, DT);
+ break;
case Instruction::And:
- return SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, DT);
+ Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, DT);
+ break;
case Instruction::Or:
- return SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, DT);
+ Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, DT);
+ break;
case Instruction::ICmp:
- return SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
- I->getOperand(0), I->getOperand(1), TD, DT);
+ Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
+ I->getOperand(0), I->getOperand(1), TD, DT);
+ break;
case Instruction::FCmp:
- return SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
- I->getOperand(0), I->getOperand(1), TD, DT);
+ Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
+ I->getOperand(0), I->getOperand(1), TD, DT);
+ break;
case Instruction::Select:
- return SimplifySelectInst(I->getOperand(0), I->getOperand(1),
- I->getOperand(2), TD, DT);
+ Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
+ I->getOperand(2), TD, DT);
+ break;
case Instruction::GetElementPtr: {
SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
- return SimplifyGEPInst(&Ops[0], Ops.size(), TD, DT);
+ Result = SimplifyGEPInst(&Ops[0], Ops.size(), TD, DT);
+ break;
}
case Instruction::PHI:
- return SimplifyPHINode(cast<PHINode>(I), DT);
+ Result = SimplifyPHINode(cast<PHINode>(I), DT);
+ break;
}
+
+ /// If called on unreachable code, the above logic may report that the
+ /// instruction simplified to itself. Make life easier for users by
+ /// detecting that case here, returning null if it occurs.
+ return Result == I ? 0 : Result;
}
/// ReplaceAndSimplifyAllUses - Perform From->replaceAllUsesWith(To) and then