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From: "ysrumyan at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/56151] New: Performance degradation after r194054 on x86 Atom.
Date: Wed, 30 Jan 2013 15:18:00 -0000	[thread overview]
Message-ID: <bug-56151-4@http.gcc.gnu.org/bugzilla/> (raw)


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56151

             Bug #: 56151
           Summary: Performance degradation after r194054 on x86 Atom.
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: ysrumyan@gmail.com


For simple test-case extracted from one important benchmark we see number
instrctions increasing after fix r194054. If we compile test-case with compiler
built before this revision we have only 6 instructions for store stmt:

    movl    %edx, %ebx
    movl    %edx, %ebp
    sarl    $5, %ebx
    andl    $31, %ebp
    movl    setmask(,%ebp,4), %ebp
    orl    %ebp, (%edi,%ebx,4)

but after this fix we got 9 instrctions for it:

    movl    %edx, %ebx
    movl    56(%esp), %esi
    sarl    $5, %ebx
    movl    %edx, %ebp
    andl    $31, %ebp
    leal    (%esi,%ebx,4), %esi
    movl    (%esi), %ebx
    orl    setmask(,%ebp,4), %ebx
    movl    %ebx, (%esi)

To reproduce it is sufficient to compile with the following options:

-O2 -ffast-math -msse2 -mfpmath=sse -m32 -march=atom -mtune=atom


             reply	other threads:[~2013-01-30 15:18 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-30 15:18 ysrumyan at gmail dot com [this message]
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
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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