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Re: [RFC] Cleanup DW_CFA_GNU_args_size handling
- From: Georg-Johann Lay <avr at gjlay dot de>
- To: Richard Henderson <rth at redhat dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, Denis Chertykov <chertykov at gmail dot com>, Denis Chertykov <chertykov at gmail dot com>
- Date: Wed, 03 Aug 2011 14:14:51 +0200
- Subject: Re: [RFC] Cleanup DW_CFA_GNU_args_size handling
- References: <4E36D44A.6020607@redhat.com> <4E36F3AF.3070300@gjlay.de> <4E36F48F.4040106@redhat.com>
Richard Henderson wrote:
> On 08/01/2011 11:42 AM, Georg-Johann Lay wrote:
>> Is there a specific reason not to define
>> ACCUMULATE_OUTGOING_ARGS on AVR?
>
> Yes. So that you can use PUSH. But as I said in PR49881,
> you probably want to provide -maccumulate-outgoing-args.
>
> I have a follow-up patch to the last one in that PR...
>
>
> r~
PUSH is fine but what about POP?
It's very expensive to pop several bytes, i.e. disabling IRQs, loading and storing SP and the like.
Usung store+displacement has not this drawback and as I wrote, come code degradations you explained
in PR49881 are artifacts of PR46278, i.e. fake X addressing.
Johann