[Bug tree-optimization/32921] [4.3 Regression] Revision 126326 causes 12% slowdown

[dberlin at dberlin dot org]

------- Comment #14 from dberlin at gcc dot gnu dot org  2007-10-17 17:41 -------
Subject: Re:  [4.3 Regression] Revision 126326 causes 12% slowdown

On 17 Oct 2007 16:59:25 -0000, pinskia at gcc dot gnu dot org
<gcc-bugzilla@gcc.gnu.org> wrote:
>
>
> ------- Comment #13 from pinskia at gcc dot gnu dot org  2007-10-17 16:59 -------
> Can someone explain this may_alias behavior:
>
> so we have in the IR:
>   # VUSE <SFT.30_53>
> D.892_19 = qav.data;
> D.893_20 = (real8[0:] *) D.892_19;
>
>
>  in may_alias we get a constraint of:
>  D.892_19 = qav
> D.893_20 = D.892_19
>
>
>
> Isn't this wrong?  D. 892_19 shouldn't just point to anywhere?

qav should have a constraint somewhere that says qav = &ANYTHING

You won't directly see D.892_19 = ANYTHING


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32921