[Bug target/30271] -mstrict-align can an store extra for struct agrument passing

["guojiufu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30271

Jiu Fu Guo <guojiufu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |guojiufu at gcc dot gnu.org

--- Comment #13 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #10)
> (In reply to comment #9)
> > Andrew, 
> > 
> > What is your point here?
> 
> My point here is that currently we do:
>       gi->frame_related =
>         (base == frame_pointer_rtx) || (base == hard_frame_pointer_rtx);
> 
> But if we change it to be:
>       gi->frame_related =
>         (base == frame_pointer_rtx) || (base == hard_frame_pointer_rtx)
>         || (base == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM]);
> 
> It would delete the store (at least in a 4.3 based compiler). 
> arg_pointer_rtx is the incoming argument space so if it is a fixed register
> it will be also frame related and we can safely delete the stores to this
> space.

https://gcc.gnu.org/pipermail/gcc-patches/2023-December/639550.html is using
this idea too.  And the 'std' in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30271#c2 disappeared.