Xi Ruoyao <xry...@mengyan1223.wang> writes: >> >> If we have to go this way, I think it’s better to make the change you >> suggested above, >> and then also update the documentation, both internal documentation on >> how to define >> the hook and the user level documentation on what the user might >> expect when using >> this option (i.e, it’s possible that the compiler might clear more >> registers than the user >> requests on some targets due to the implementation limitation). >> >> I can make this change if we decide to do this. > > I'd vote for this. Richard?
Fine by me too, although I don't think this should be mentioned in the user documentation. E.g. used-arg means that non-argument, non-return registers can have any value on return from the function; the compiler doesn't make any guarantees. If the compiler happens to use a temporary register in the implementation of the option, and if that temporary register happens to still be zero on return, then that's OK. It's just an internal implementation detail. The same thing could happen for any part of the epilogue. Thanks, Richard
