diff options
Diffstat (limited to 'llvm/lib/Analysis/InstructionSimplify.cpp')
| -rw-r--r-- | llvm/lib/Analysis/InstructionSimplify.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index fd7a4de6903..6ac1ae8d5ed 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -1346,6 +1346,11 @@ static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap()) return X; + // Arithmetic shifting an all-sign-bit value is a no-op. + unsigned NumSignBits = ComputeNumSignBits(Op0); + if (NumSignBits == Op0->getType()->getScalarSizeInBits()) + return Op0; + return nullptr; } |
