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Re: [patch] conditional store elimination
- From: "Richard Guenther" <richard dot guenther at gmail dot com>
- To: "Tehila Meyzels" <TEHILA at il dot ibm dot com>
- Cc: "Michael Matz" <matz at suse dot de>, gcc-patches at gcc dot gnu dot org
- Date: Thu, 11 Oct 2007 12:15:55 +0200
- Subject: Re: [patch] conditional store elimination
- References: <OFDBB26488.DC2C893B-ONC225736F.005757D0-C2257371.00375C5C@il.ibm.com>
On 10/11/07, Tehila Meyzels <TEHILA@il.ibm.com> wrote:
>
> Hi,
>
> On 8/28/07, Michael Matz <matz@suse.de> wrote:
>
> >Hi,
> >
> >this patch fixes PR middle-end/27313 and thereby a performance problem on
> >456.hmmer (which now runs in 798 instead of 1080 seconds, i.e. 26%
> >improvement). We talked about how to integrate this better with if
> >conversion and make it also do load hoisting, but I fear we won't get to
> >that during the time left for stage 2, and meanwhile I'd really like to
> >have that improvement in 4.3.
> >
> >I tweaked the patch a bit to only do the transformation by default if the
> >target has conditional moves.
>
> Sorry, but I didn't find where in the patch you are checking this.
> Could you please enlighten?
It's enabled by default for HAVE_conditional_move targets only. From toplev.c:
if (flag_tree_cselim == AUTODETECT_VALUE)
#ifdef HAVE_conditional_move
flag_tree_cselim = 1;
#else
flag_tree_cselim = 0;
#endif
Richard.