diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 3caa4cf10e..63de8fa222 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -1867,12 +1867,28 @@ Instruction *InstCombiner::visitRem(BinaryOperator &I) { if (isPowerOf2_64(C->getValue())) return BinaryOperator::createAnd(Op0, SubOne(C)); - if (SelectInst *SI = dyn_cast<SelectInst>(Op0)) - if (Instruction *R = FoldOpIntoSelect(I, SI, this)) - return R; - if (isa<PHINode>(Op0)) - if (Instruction *NV = FoldOpIntoPhi(I)) - return NV; + if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) { + if (SelectInst *SI = dyn_cast<SelectInst>(Op0I)) { + if (Instruction *R = FoldOpIntoSelect(I, SI, this)) + return R; + } else if (isa<PHINode>(Op0I)) { + if (Instruction *NV = FoldOpIntoPhi(I)) + return NV; + } else if (Op0I->getOpcode() == Instruction::Mul) { + // X*C1%C2 --> 0 iff C1%C2 == 0 + if (ConstantInt *MulRHS = dyn_cast<ConstantInt>(Op0I->getOperand(1))) { + if (ConstantExpr::getRem(MulRHS, RHS)->isNullValue()) + return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); + } + } else if (Op0I->getOpcode() == Instruction::Shl) { + // (X<<C1)%C2 --> 0 iff (1<<C1)%C2 == 0 + if (Constant *ShRHS = dyn_cast<Constant>(Op0I->getOperand(1))) { + ShRHS = ConstantExpr::getShl(ConstantInt::get(I.getType(), 1), ShRHS); + if (ConstantExpr::getRem(ShRHS, RHS)->isNullValue()) + return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); + } + } + } } if (Instruction *RHSI = dyn_cast<Instruction>(I.getOperand(1))) { |