RE: Integer promotion for register based arguments

["Jon Beniston" <jon at beniston dot com>]

Hi Eric,

> > I guess my question is what would I need to change to make it work
> > like the ARM port? I can't see how this is being controlled.
> 
> Try TARGET_PROMOTE_PROTOTYPES.

Thanks, actually it does turn out to be this, but I was confused by the
documentation. If this returns true, I see sign extension performed in the
callee, if false, no sign extension is performed in the callee.

The documentation for this comes under the " Passing Function Arguments on
the Stack" section, which says:

"This target hook returns true if an argument declared in a prototype as an
integral type smaller than int should actually be passed as an int. In
addition to avoiding errors in certain cases of mismatch, it also makes for
better code on certain machines."

I would have thought if the args smaller than an int are actually passed as
an int, that would have meant the promotion had already taken place and so
wasn't needed in the callee. It could also be said that it makes worse code
on other machines :)

Thanks,
Jon