[Bug target/43225] Structure copies not vectorized

["pinskia at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #1 from pinskia at gmail dot com  2010-03-02 05:24 -------
Subject: Re:   New: Structure copies not vectorized



Sent from my iPhone

On Mar 1, 2010, at 8:23 PM, "astrange at ithinksw dot com"
<gcc-bugzilla@gcc.gnu.org 
 > wrote:

> Source:
>
> #include <emmintrin.h>
>
> struct a1 { char l[16];};

Are sure that struct has 128 bit alignment because I think it only has  
8bit alignment.


> struct a2 { __m128i l; };
>
> void f1(struct a1 *a, struct a1 *b)
> {
>    *a = *b;
> }
>
> void f2(struct a2 *a, struct a2 *b)
> {
>    *a = *b;
> }
>
>> /usr/local/gcc45/bin/gcc -O3 -fomit-frame-pointer -S copy_gcc.c
> _f1:
>        movq    (%rsi), %rax
>        movq    %rax, (%rdi)
>        movq    8(%rsi), %rax
>        movq    %rax, 8(%rdi)
>        ret
>
> _f2:
>        movdqa  (%rsi), %xmm0
>        movdqa  %xmm0, (%rdi)
>        ret
>
> Both are appropriately aligned and should use movdqa. This might not  
> show up in
> generic code, but I could have used it in an ffmpeg optimization.
>
>
> -- 
>           Summary: Structure copies not vectorized
>           Product: gcc
>           Version: 4.5.0
>            Status: UNCONFIRMED
>          Severity: enhancement
>          Priority: P3
>         Component: target
>        AssignedTo: unassigned at gcc dot gnu dot org
>        ReportedBy: astrange at ithinksw dot com
>  GCC host triplet: x86_64-*-*
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43225
>


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43225