diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp index d8546c7b89a..01b1f4cdf3c 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp @@ -1166,6 +1166,13 @@ static Instruction *foldSelectShuffles(ShuffleVectorInst &Shuf) { if (isa<Constant>(X)) return nullptr; + // Constant operands must be on the same side of each binop. We can't fold: + // shuffle (sdiv X, C0), (sdiv C1, X). + bool B00IsConst = isa<Constant>(B0->getOperand(0)); + bool B10IsConst = isa<Constant>(B1->getOperand(0)); + if (B00IsConst != B10IsConst) + return nullptr; + // Remove a binop and the shuffle by rearranging the constant: // shuffle (op X, C0), (op X, C1), M --> op X, C' // shuffle (op C0, X), (op C1, X), M --> op C', X @@ -1178,8 +1185,7 @@ static Instruction *foldSelectShuffles(ShuffleVectorInst &Shuf) { NewC = getSafeVectorConstantForIntDivRem(NewC); BinaryOperator::BinaryOps Opc = B0->getOpcode(); - bool Op0IsConst = isa<Constant>(B0->getOperand(0)); - Instruction *NewBO = Op0IsConst ? BinaryOperator::Create(Opc, NewC, X) : + Instruction *NewBO = B00IsConst ? BinaryOperator::Create(Opc, NewC, X) : BinaryOperator::Create(Opc, X, NewC); // Flags are intersected from the 2 source binops. |
