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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/65215] [5 Regression] Bswap load miscompilation
Date: Thu, 26 Feb 2015 11:36:00 -0000	[thread overview]
Message-ID: <bug-65215-4-nuFTSpPMm2@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-65215-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65215

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #1)
> Created attachment 34879 [details]
> gcc5-pr65215.patch
> 
> Untested fix.  There are still issues left, e.g. I can't understand the
> "bswap &&" part in
>       if (bswap
>           && align < GET_MODE_ALIGNMENT (TYPE_MODE (load_type))
>           && SLOW_UNALIGNED_ACCESS (TYPE_MODE (load_type), align))
>         return false;
> Don't you use the new MEM_REF even for the !bswap (aka nop) case?  So, I
> don't see how it would be safe to generate that.
> And the testsuite coverage of this is definitely suboptimal, from endianity
> POV, bitfields etc.

I suggested that change (remove bswap &&) multiple times, but it got lost
appearantly.  (I even remember applying that change myself!?)


  parent reply	other threads:[~2015-02-26 10:33 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-26  0:27 [Bug tree-optimization/65215] New: " jakub at gcc dot gnu.org
2015-02-26  0:44 ` [Bug tree-optimization/65215] " jakub at gcc dot gnu.org
2015-02-26 11:07 ` jakub at gcc dot gnu.org
2015-02-26 11:17 ` jakub at gcc dot gnu.org
2015-02-26 11:32 ` jakub at gcc dot gnu.org
2015-02-26 11:36 ` rguenth at gcc dot gnu.org [this message]
2015-02-26 11:45 ` jakub at gcc dot gnu.org
2015-02-26 11:45 ` thopre01 at gcc dot gnu.org
2015-02-26 12:28 ` thopre01 at gcc dot gnu.org
2015-02-26 12:37 ` jakub at gcc dot gnu.org
2015-02-26 12:39 ` rguenth at gcc dot gnu.org
2015-02-26 12:46 ` rguenth at gcc dot gnu.org
2015-02-26 22:50 ` jakub at gcc dot gnu.org
2015-02-27  0:21 ` jakub at gcc dot gnu.org

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