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Re: [PATCH] Allow &va_list in tree-stdarg
- From: Richard Guenther <rguenth at tat dot physik dot uni-tuebingen dot de>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Fri, 20 May 2005 14:11:23 +0200 (CEST)
- Subject: Re: [PATCH] Allow &va_list in tree-stdarg
On Fri, 20 May 2005, Jakub Jelinek wrote:
> On Fri, May 20, 2005 at 01:56:38PM +0200, Richard Guenther wrote:
> > This patch allows &va_list in tree-stdarg optimization as
> > it shows up on x86_64 with its va_list type "struct ap"
> > and the C frontend modified to emit &ap for ap-to-pointer
> > decay, instead of &ap. I guess this should also show up
> > with current C++ on that architecture.
> > Is such change ok with you?
> Yes, though I can't approve it...
> > Would it even be correct to
> > omit the integer_zerop check for the array index? I get
> No, I think that check should be there. stdarg optimization
> should be as strict as possible, whenever it sees something
> it does not understand it should bail out instead of risking
> bad code generation. struct type va_list is one member array,
> so zero index should be enforced there.
> > some extra failures in this case on i686, namely no longer
> > thinking that for stdarg-3.c:f4() the va_list escapes.
> You mean even with the patch below?
No, only with the integer_zerop check removed of course.
Richard Guenther <richard dot guenther at uni-tuebingen dot de>