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From: "ebotcazou at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/59461] missed zero-extension elimination in the combiner
Date: Wed, 11 Dec 2013 09:51:00 -0000	[thread overview]
Message-ID: <bug-59461-4-1YhvAS19Iz@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-59461-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59461

--- Comment #3 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> I wonder if x86_64 is also affected as it has implicitely zero/sign-extending
> loads as well.

Not for this testcase at least, where the code is (and has always been)
optimal:

ee_isdigit2:
.LFB0:
        .cfi_startproc
        movl    %edi, %edi
        movzbl  zeb_test_array(%rdi), %eax
        subl    $48, %eax
        cmpb    $9, %al
        setbe   %al
        ret
        .cfi_endproc

because the x86-64 can perform the addition in QImode directly.


      parent reply	other threads:[~2013-12-11  9:51 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-10 23:13 [Bug rtl-optimization/59461] New: " ebotcazou at gcc dot gnu.org
2013-12-10 23:14 ` [Bug rtl-optimization/59461] " ebotcazou at gcc dot gnu.org
2013-12-11  9:23 ` rguenth at gcc dot gnu.org
2013-12-11  9:51 ` ebotcazou at gcc dot gnu.org [this message]

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