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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/56151] [4.8 Regression] Performance degradation after r194054 on x86 Atom.
Date: Fri, 08 Feb 2013 15:29:00 -0000 [thread overview]
Message-ID: <bug-56151-4-DJFLvnEuhQ@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-56151-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56151
--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-02-08 15:29:12 UTC ---
(In reply to comment #4)
> Patch to help explain the problem:
>
> Index: optabs.c
> ===================================================================
> --- optabs.c (revision 195687)
> +++ optabs.c (working copy)
> @@ -1452,8 +1452,13 @@ expand_binop_directly (enum machine_mode
> {
> /* If PAT is composed of more than one insn, try to add an appropriate
> REG_EQUAL note to it. If we can't because TEMP conflicts with an
> - operand, call expand_binop again, this time without a target. */
> + operand, call expand_binop again, this time without a target.
> +
> + However, if target is a MEM, just accept the lossage of not having
> + a REG_EQUAL note. This avoids splitting up insns of the form
> + "MEM=MEM op X", a form we may not be able to reconstruct later. */
> if (INSN_P (pat) && NEXT_INSN (pat) != NULL_RTX
> + && ! (target && MEM_P (target))
> && ! add_equal_note (pat, ops[0].value, optab_to_code (binoptab),
> ops[1].value, ops[2].value))
> {
Shouldn't the && ! (target && MEM_P (target))
come after add_equal_note call, not before it? I.e. shouldn't we try to add
the note if possible?
next prev parent reply other threads:[~2013-02-08 15:29 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-30 15:18 [Bug tree-optimization/56151] New: " ysrumyan at gmail dot com
2013-01-30 15:20 ` [Bug tree-optimization/56151] " ysrumyan at gmail dot com
2013-01-30 16:04 ` [Bug rtl-optimization/56151] " rguenth at gcc dot gnu.org
2013-01-31 9:24 ` [Bug rtl-optimization/56151] [4.8 Regression] " rguenth at gcc dot gnu.org
2013-02-03 0:46 ` steven at gcc dot gnu.org
2013-02-03 1:05 ` steven at gcc dot gnu.org
2013-02-04 10:34 ` ebotcazou at gcc dot gnu.org
2013-02-04 12:04 ` jakub at gcc dot gnu.org
2013-02-04 17:14 ` jakub at gcc dot gnu.org
2013-02-04 17:59 ` steven at gcc dot gnu.org
2013-02-04 18:20 ` jakub at gcc dot gnu.org
2013-02-08 15:23 ` rguenth at gcc dot gnu.org
2013-02-08 15:29 ` jakub at gcc dot gnu.org [this message]
2013-02-11 15:42 ` jakub at gcc dot gnu.org
2013-02-12 10:38 ` jakub at gcc dot gnu.org
2013-02-12 10:39 ` jakub at gcc dot gnu.org
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