[Bug c/60660] alloca function for inlines that allocates on caller stack

[josh at joshtriplett dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60660

--- Comment #4 from Josh Triplett <josh at joshtriplett dot org> ---
(In reply to Andrew Pinski from comment #1)
> This is much harder than you think really.  since you have to move all the
> arguments of the callee function

That I'm aware of, but it should be less of an issue with an always inline
function, where you shouldn't necessarily be passing stack arguments in the
first place.

(In reply to Andrew Pinski from comment #2)
> >without multiple evaluation of the variable arguments as a macro would.
> 
> You can use statement expressions with typeof extension to get around the
> issue of multiple evaluation issue of macros already.

Not with a variable argument list, due to limitations in the C preprocessor.

(In reply to Marek Polacek from comment #3)
> Note that even functions marked as always_inline might not be in fact
> inlineable.

This seems like exactly the same limitation that __builtin_va_arg_pack has.