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[Bug rtl-optimization/25130] [4.1/4.2 Regression] miscompilation in GCSE
- From: "jakub at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 13 Jun 2011 12:48:41 +0000
- Subject: [Bug rtl-optimization/25130] [4.1/4.2 Regression] miscompilation in GCSE
- Auto-submitted: auto-generated
- References: <bug-25130-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25130
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |REOPENED
CC| |jakub at gcc dot gnu.org
Resolution|FIXED |
Known to fail| |
--- Comment #23 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-06-13 12:47:14 UTC ---
(In reply to comment #21)
> The patch that was committed (especially the cse.c exp_equiv_p part) seems like
> a big hammer, and it does cause missed optimization opportunities.
>
> Reverting it on gcc-4.1-branch, and instead applying the patch for PR41033,
> also gives a compiler that correctly compiles this testcase.
>
> PR41033 adds a test for flag_strict_aliasing to nonverlapping_component_refs_p,
> which corrects the return value for canon_true_dependence mentioned in comment
> #9.
>
> Steven, are you certain that this patch is necessary in light of this?
As PR49390 shows, yes.