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References: <bug-27567-7667@http.gcc.gnu.org/bugzilla/>
Subject: [Bug middle-end/27567] [4.0/4.1 Regression] __builtin_memcpy generates redundant stores/moves.
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From: "pluto at agmk dot net" <gcc-bugzilla@gcc.gnu.org>
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------- Comment #8 from pluto at agmk dot net  2007-02-14 22:24 -------
still bad :/

float convert( unsigned in )
{
        float f;
        __builtin_memcpy( &f, &in, sizeof( in ) );
        return f;
}

unsigned short load( void* p )
{
        unsigned short v;
        __builtin_memcpy( &v, p, sizeof( v ) );
        return v;
}

convert:
        movl    %edi, -4(%rsp)
        movss   -4(%rsp), %xmm1
        movaps  %xmm1, %xmm0
        ret

load:
        movzwl  (%rdi), %eax
        movw    %ax, -2(%rsp)
        movzwl  %ax, %eax
        ret

gcc-42 (20070207)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27567