diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index b020a85dcc..79a551f70c 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -446,6 +446,7 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) { Instruction *Or = BinaryOperator::create(Instruction::Or, Op0NotVal, Op1NotVal,I.getName()+".demorgan", &I); + WorkList.push_back(Or); return BinaryOperator::createNot(Or); } @@ -470,15 +471,25 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) { if (RHS->isAllOnesValue()) return ReplaceInstUsesWith(I, Op1); - if (Value *X = dyn_castNotVal(Op0)) // ~A | A == -1 - if (X == Op1) - return ReplaceInstUsesWith(I, - ConstantIntegral::getAllOnesValue(I.getType())); + Value *Op0NotVal = dyn_castNotVal(Op0); + Value *Op1NotVal = dyn_castNotVal(Op1); - if (Value *X = dyn_castNotVal(Op1)) // A | ~A == -1 - if (X == Op0) - return ReplaceInstUsesWith(I, - ConstantIntegral::getAllOnesValue(I.getType())); + if (Op1 == Op0NotVal) // ~A | A == -1 + return ReplaceInstUsesWith(I, + ConstantIntegral::getAllOnesValue(I.getType())); + + if (Op0 == Op1NotVal) // A | ~A == -1 + return ReplaceInstUsesWith(I, + ConstantIntegral::getAllOnesValue(I.getType())); + + // (~A | ~B) == (~(A & B)) - Demorgan's Law + if (Op0NotVal && Op1NotVal && isOnlyUse(Op0) && isOnlyUse(Op1)) { + Instruction *And = BinaryOperator::create(Instruction::And, Op0NotVal, + Op1NotVal,I.getName()+".demorgan", + &I); + WorkList.push_back(And); + return BinaryOperator::createNot(And); + } return Changed ? &I : 0; } |