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From: "tony.poppleton at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/47477] [4.6/4.7/4.8/4.9 regression] Sub-optimal mov at end of method
Date: Wed, 10 Apr 2013 01:44:00 -0000
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X-Bugzilla-Component: rtl-optimization
X-Bugzilla-Keywords: missed-optimization, ra
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47477

--- Comment #13 from Tony Poppleton <tony.poppleton at gmail dot com> 2013-04-10 01:44:18 UTC ---
The test case appears to be fixed in GCC 4.8.0, compiling with just -S and -O3,
the asm
output is now a much simpler:

        .file   "test.c"
        .text
        .p2align 4,,15
        .globl  add
        .type   add, @function
add:
.LFB0:
        .cfi_startproc
        andq    $-2, %rsi
        leaq    (%rdi,%rsi), %rax
        ret
        .cfi_endproc
.LFE0:
        .size   add, .-add
        .ident  "GCC: (GNU) 4.8.0 20130316 (Red Hat 4.8.0-0.17)"
        .section        .note.GNU-stack,"",@progbits

I don't know if other test cases would reproduce the original bug however.