diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstructionCombining.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstructionCombining.cpp | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp index 65e6d2e3590..a2dd27d282a 100644 --- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp +++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp @@ -939,9 +939,19 @@ Instruction *InstCombiner::foldOpIntoPhi(Instruction &I, PHINode *PN) { // `TrueVInPred`. if (InC && !isa<ConstantExpr>(InC) && isa<ConstantInt>(InC)) InV = InC->isNullValue() ? FalseVInPred : TrueVInPred; - else + else { + // Generate the select in the same block as PN's current incoming block. + // Note: ThisBB need not be the NonConstBB because vector constants + // which are constants by definition are handled here. + // FIXME: This can lead to an increase in IR generation because we might + // generate selects for vector constant phi operand, that could not be + // folded to TrueVInPred or FalseVInPred as done for ConstantInt. For + // non-vector phis, this transformation was always profitable because + // the select would be generated exactly once in the NonConstBB. + Builder->SetInsertPoint(ThisBB->getTerminator()); InV = Builder->CreateSelect(PN->getIncomingValue(i), TrueVInPred, FalseVInPred, "phitmp"); + } NewPN->addIncoming(InV, ThisBB); } } else if (CmpInst *CI = dyn_cast<CmpInst>(&I)) { |
