[Bug target/14552] compiled trivial vector intrinsic code is inefficient

[pinskia at gmail dot com]

------- Comment #31 from pinskia at gmail dot com  2008-03-20 00:23 -------
Subject: Re:  compiled trivial vector intrinsic code is inefficient

See pr 33790.

Sent from my iPhone

On Mar 19, 2008, at 17:04, "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org 
 > wrote:

>
>
> ------- Comment #30 from ubizjak at gmail dot com  2008-03-20 00:04  
> -------
> (In reply to comment #28)
>> (In reply to comment #27)
>>> The store is not useless. Reload from "_w" is how gcc handles  
>>> double stores
>>> nowadays and is not mmx specific. It looks that some pass forgot  
>>> to check where
>>> the value came from.
>>
>> Do you happen to know if there are two different modes at work  
>> here?  If so
>> there are patches which fix this up in DSE and post-reload CSE.
>
> Yes, from comment #24 (slightly changed):
>
> typedef short mmxw  __attribute__ ((vector_size (8)));
> typedef int   mmxdw __attribute__ ((vector_size (8)));
>
> mmxdw dw;
> mmxw w;
>
> so, we have V4HI and V2SI.
>
>
> -- 
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14552
>


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14552