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Date: Thu, 18 Dec 2003 17:39:00 -0000
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From: "steven at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
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Reply-To: gcc-bugzilla@gcc.gnu.org
Subject: [Bug optimization/12419] [3.3/3.4 Regression] Performace regression: poor optimization of const memory
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X-SW-Source: 2003-12/txt/msg01929.txt.bz2
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------- Additional Comments From steven at gcc dot gnu dot org  2003-12-18 17:29 -------
The bug is still present on mainline... 
(cc1 -O2 -fomit-frame-pointer-march=i686 -mtune=i686 ): 
 
foo: 
        pushl   %ebx 
        subl    $8, %esp 
        movl    a, %ebx 
        call    f 
        movl    a, %eax 
        addl    $8, %esp 
        addl    %eax, %ebx 
        movl    %ebx, %eax 
        popl    %ebx 
        ret 
 
 
Just for fun, here's what tree-ssa makes of it 
 
foo: 
        pushl   %ebx 
        subl    $8, %esp 
        movl    a, %ebx 
        call    f 
        addl    $8, %esp 
        leal    (%ebx,%ebx), %eax 
        popl    %ebx 
        ret 
 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2003-09-27 06:36:21         |2003-12-18 17:29:55
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12419