diff options
Diffstat (limited to 'llvm/lib/Analysis/InstructionSimplify.cpp')
| -rw-r--r-- | llvm/lib/Analysis/InstructionSimplify.cpp | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index 807bbd20ac0..0e522cb4e49 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -4085,8 +4085,9 @@ Value *llvm::SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty, static Value *SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask, Type *RetTy, const Query &Q, unsigned MaxRecurse) { + Type *InVecTy = Op0->getType(); unsigned MaskNumElts = Mask->getType()->getVectorNumElements(); - unsigned InVecNumElts = Op0->getType()->getVectorNumElements(); + unsigned InVecNumElts = InVecTy->getVectorNumElements(); auto *Op0Const = dyn_cast<Constant>(Op0); auto *Op1Const = dyn_cast<Constant>(Op1); @@ -4108,11 +4109,22 @@ static Value *SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask, MaskSelects1 = true; } if (!MaskSelects0 && Op1Const) - return ConstantFoldShuffleVectorInstruction(UndefValue::get(Op0->getType()), + return ConstantFoldShuffleVectorInstruction(UndefValue::get(InVecTy), Op1Const, Mask); if (!MaskSelects1 && Op0Const) - return ConstantFoldShuffleVectorInstruction( - Op0Const, UndefValue::get(Op0->getType()), Mask); + return ConstantFoldShuffleVectorInstruction(Op0Const, + UndefValue::get(InVecTy), Mask); + + // A shuffle of a splat is always the splat itself. Legal if the shuffle's + // value type is same as the input vectors' type. + if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op0)) + if (!MaskSelects1 && RetTy == InVecTy && + OpShuf->getMask()->getSplatValue()) + return Op0; + if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op1)) + if (!MaskSelects0 && RetTy == InVecTy && + OpShuf->getMask()->getSplatValue()) + return Op1; return nullptr; } |
