diff options
Diffstat (limited to 'llvm/lib/IR/ConstantFold.cpp')
| -rw-r--r-- | llvm/lib/IR/ConstantFold.cpp | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/llvm/lib/IR/ConstantFold.cpp b/llvm/lib/IR/ConstantFold.cpp index 3243ddd..d9564a3 100644 --- a/llvm/lib/IR/ConstantFold.cpp +++ b/llvm/lib/IR/ConstantFold.cpp @@ -1105,7 +1105,14 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1, } // Binary operations propagate poison. - if (isa<PoisonValue>(C1) || isa<PoisonValue>(C2)) + // FIXME: Currently, or/and i1 poison aren't folded into poison because + // it causes miscompilation when combined with another optimization in + // InstCombine (select i1 -> and/or). The select fold is wrong, but + // fixing it requires an effort, so temporarily disable this until it is + // fixed. + bool PoisonFold = !C1->getType()->isIntegerTy(1) || + (Opcode != Instruction::Or && Opcode != Instruction::And); + if (PoisonFold && (isa<PoisonValue>(C1) || isa<PoisonValue>(C2))) return PoisonValue::get(C1->getType()); // Handle scalar UndefValue and scalable vector UndefValue. Fixed-length |