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Re: [PATCH v2] Clean up check_pf allocation pattern. addresses
- From: OndÅej BÃlka <neleai at seznam dot cz>
- To: Andreas Schwab <schwab at suse dot de>
- Cc: libc-alpha at sourceware dot org
- Date: Wed, 28 May 2014 12:58:23 +0200
- Subject: Re: [PATCH v2] Clean up check_pf allocation pattern. addresses
- Authentication-results: sourceware.org; auth=none
- References: <mvm61n3puag dot fsf at hawking dot suse dot de> <20140324165711 dot GA6719 at domone dot podge> <87k3bjzcpb dot fsf at igel dot home> <20140325214344 dot GA23074 at domone dot podge> <mvmfvm5l20i dot fsf at hawking dot suse dot de> <20140527205640 dot GB21440 at domone dot podge> <mvmmwe2jilf dot fsf at hawking dot suse dot de>
On Wed, May 28, 2014 at 12:36:12PM +0200, Andreas Schwab wrote:
> OndÅej BÃlka <neleai@seznam.cz> writes:
>
> > @@ -137,20 +142,9 @@ make_request (int fd, pid_t pid)
> > #else
> > const size_t buf_size = __getpagesize ();
> > #endif
> > - bool use_malloc = false;
> > char *buf;
> > - size_t alloca_used = 0;
> >
> > - if (__libc_use_alloca (buf_size))
> > - buf = alloca_account (buf_size, alloca_used);
> > - else
> > - {
> > - buf = malloc (buf_size);
> > - if (buf != NULL)
> > - use_malloc = true;
> > - else
> > - goto out_fail;
> > - }
> > + buf = alloca (buf_size);
>
> Does the compiler optimize this into a plain array if buf_size is
> constant?
>
No, that would not be problem if gcc optimized alloca alignment which it
does not do now.