diff options
Diffstat (limited to 'lib/Transforms/Scalar/InstructionCombining.cpp')
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index bb0e099..06a5660 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -2661,7 +2661,7 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) { if (isa<UndefValue>(I.getOperand(1))) // undef * X -> 0 return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); - // Simplify mul instructions with a constant RHS... + // Simplify mul instructions with a constant RHS. if (Constant *Op1 = dyn_cast<Constant>(I.getOperand(1))) { if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { @@ -2765,9 +2765,20 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) { } } + /// i1 mul -> i1 and. if (I.getType() == Type::getInt1Ty(*Context)) return BinaryOperator::CreateAnd(Op0, I.getOperand(1)); + // X*(1 << Y) --> X << Y + // (1 << Y)*X --> X << Y + { + Value *Y; + if (match(Op0, m_Shl(m_One(), m_Value(Y)))) + return BinaryOperator::CreateShl(I.getOperand(1), Y); + if (match(I.getOperand(1), m_Shl(m_One(), m_Value(Y)))) + return BinaryOperator::CreateShl(Op0, Y); + } + // If one of the operands of the multiply is a cast from a boolean value, then // we know the bool is either zero or one, so this is a 'masking' multiply. // See if we can simplify things based on how the boolean was originally |