diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index bc8744480c5..aae1e14f9db 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -2928,17 +2928,19 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) { if (RHS->isAllOnesValue()) return BinaryOperator::CreateNeg(Op0); - ConstantInt *RHSNeg = cast<ConstantInt>(ConstantExpr::getNeg(RHS)); - APInt RHSNegAPI(RHSNeg->getValue()); - - APInt NegOne = -APInt(RHSNeg->getBitWidth(), 1, true); - APInt TwoToExp(RHSNeg->getBitWidth(), 1 << (RHSNeg->getBitWidth() - 1)); - // -X/C -> X/-C, if and only if negation doesn't overflow. - if ((RHS->getValue().isNegative() && RHSNegAPI.slt(TwoToExp - 1)) || - (RHS->getValue().isNonNegative() && RHSNegAPI.sgt(TwoToExp * NegOne))) { - if (Value *LHSNeg = dyn_castNegVal(Op0)) { - if (ConstantInt *CI = dyn_cast<ConstantInt>(LHSNeg)) { + if (Value *LHSNeg = dyn_castNegVal(Op0)) { + if (ConstantInt *CI = dyn_cast<ConstantInt>(LHSNeg)) { + ConstantInt *RHSNeg = cast<ConstantInt>(ConstantExpr::getNeg(RHS)); + APInt RHSNegAPI(RHSNeg->getValue()); + + APInt NegOne = -APInt(RHSNeg->getBitWidth(), 1, true); + APInt TwoToExp(RHSNeg->getBitWidth(), 1 << (RHSNeg->getBitWidth() - 1)); + + if ((RHS->getValue().isNegative() && + RHSNegAPI.slt(TwoToExp - 1)) || + (RHS->getValue().isNonNegative() && + RHSNegAPI.sgt(TwoToExp * NegOne))) { ConstantInt *CINeg = cast<ConstantInt>(ConstantExpr::getNeg(CI)); APInt CINegAPI(CINeg->getValue()); |
