[LLVMdev] MachineInstr::isSafeToMove()

[Jonas Paulsson]

Hi,

I have a question regarding this method, as i have discovered a case where it seems very far from 'strict'.

I had two MI's, A and B, where A is !isSafeToMove():

A
B

TwoAddress pass changes the order to

B
A

, as it reschedules the LastKill MI (B).

Is this a bug in TwoAdress, or is it the case that isSafeToMove() is weaker than isSchedulingBoundary() so that these indirect violations are expected and accepted in TwoAddress and elsewhere?

Thanks,

Jonas