diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 4e36927200..1ace95f28b 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -493,19 +493,31 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) { return ReplaceInstUsesWith(I, Op1); // and X, -1 == X - if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1)) + if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1)) { if (RHS->isAllOnesValue()) return ReplaceInstUsesWith(I, Op0); + // (X ^ C1) & C2 --> (X & C2) ^ (C1&C2) + if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) + if (Op0I->getOpcode() == Instruction::Xor && isOnlyUse(Op0)) + if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) { + std::string Op0Name = Op0I->getName(); Op0I->setName(""); + Instruction *And = BinaryOperator::create(Instruction::And, + Op0I->getOperand(0), RHS, + Op0Name); + InsertNewInstBefore(And, I); + return BinaryOperator::create(Instruction::Xor, And, *RHS & *Op0CI); + } + } + Value *Op0NotVal = dyn_castNotVal(Op0); Value *Op1NotVal = dyn_castNotVal(Op1); // (~A & ~B) == (~(A | B)) - Demorgan's Law if (Op0NotVal && Op1NotVal && isOnlyUse(Op0) && isOnlyUse(Op1)) { Instruction *Or = BinaryOperator::create(Instruction::Or, Op0NotVal, - Op1NotVal,I.getName()+".demorgan", - &I); - WorkList.push_back(Or); + Op1NotVal,I.getName()+".demorgan"); + InsertNewInstBefore(Or, I); return BinaryOperator::createNot(Or); } |