diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/Scalar/Reassociate.cpp | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/lib/Transforms/Scalar/Reassociate.cpp b/lib/Transforms/Scalar/Reassociate.cpp index 61c5c49..4a484c3 100644 --- a/lib/Transforms/Scalar/Reassociate.cpp +++ b/lib/Transforms/Scalar/Reassociate.cpp @@ -410,19 +410,23 @@ static Instruction *BreakUpSubtract(Instruction *Sub) { /// by one, change this into a multiply by a constant to assist with further /// reassociation. static Instruction *ConvertShiftToMul(Instruction *Shl) { - if (!isReassociableOp(Shl->getOperand(0), Instruction::Mul) && - !(Shl->hasOneUse() && isReassociableOp(Shl->use_back(),Instruction::Mul))) - return 0; - - Constant *MulCst = ConstantInt::get(Shl->getType(), 1); - MulCst = ConstantExpr::getShl(MulCst, cast<Constant>(Shl->getOperand(1))); - - std::string Name = Shl->getName(); Shl->setName(""); - Instruction *Mul = BinaryOperator::createMul(Shl->getOperand(0), MulCst, - Name, Shl); - Shl->replaceAllUsesWith(Mul); - Shl->eraseFromParent(); - return Mul; + // If an operand of this shift is a reassociable multiply, or if the shift + // is used by a reassociable multiply or add, turn into a multiply. + if (isReassociableOp(Shl->getOperand(0), Instruction::Mul) || + (Shl->hasOneUse() && + (isReassociableOp(Shl->use_back(), Instruction::Mul) || + isReassociableOp(Shl->use_back(), Instruction::Add)))) { + Constant *MulCst = ConstantInt::get(Shl->getType(), 1); + MulCst = ConstantExpr::getShl(MulCst, cast<Constant>(Shl->getOperand(1))); + + std::string Name = Shl->getName(); Shl->setName(""); + Instruction *Mul = BinaryOperator::createMul(Shl->getOperand(0), MulCst, + Name, Shl); + Shl->replaceAllUsesWith(Mul); + Shl->eraseFromParent(); + return Mul; + } + return 0; } // Scan backwards and forwards among values with the same rank as element i to |