// a signed value.
//
if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(Op1)) {
- unsigned TypeBits = Op0->getType()->getPrimitiveSize()*8;
- if (CUI->getValue() >= TypeBits &&
- !(Op0->getType()->isSigned() && I.getOpcode() == Instruction::Shr))
- return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
+ if (I.getOpcode() == Instruction::Shr) {
+ unsigned TypeBits = Op0->getType()->getPrimitiveSize()*8;
+ if (CUI->getValue() >= TypeBits && !(Op0->getType()->isSigned()))
+ return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
+ }
+
+ // Check to see if we are shifting left by 1. If so, turn it into an add
+ // instruction.
+ if (I.getOpcode() == Instruction::Shl && CUI->equalsInt(1))
+ // Convert 'shl int %X, 2' to 'add int %X, %X'
+ return BinaryOperator::create(Instruction::Add, Op0, Op0, I.getName());
+
}
return 0;
}