Re: Does vectorizer support extension?

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Does vectorizer support extension?
\ H. J. Lu (20 Apr 2007)
. \ Dorit Nuzman (22 Apr 2007)
. . \ H. J. Lu (22 Apr 2007)
. . . \ Dorit Nuzman (22 Apr 2007)
. . . . \ H. J. Lu (22 Apr 2007)
. . . . . \ Dorit Nuzman (23 Apr 2007)
. . . . . . \ H. J. Lu (23 Apr 2007)
. . . . . . . \ Dorit Nuzman (23 Apr 2007)
. . . . . . . . \ H. J. Lu (23 Apr 2007)
. . . . . . . . . \ Dorit Nuzman (24 Apr 2007)
. . . . . . . . . . \ H. J. Lu (24 Apr 2007)

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Subject:	Re: Does vectorizer support extension?
Group:	Gcc
From:	H. J. Lu
Date:	24 Apr 2007

On Tue, Apr 24, 2007 at 08:55:24PM +0300, Dorit Nuzman wrote:
> "H. J. Lu" <hjl> wrote on 24/04/2007 01:03:25:
> ...
> >
> > There are
> >
> > [hjl@gnu-2 vect]$ cat pmovzxbw.c
> > typedef unsigned char vec_t;
> > typedef unsigned short vecx_t;
> >
> > in
> >
> > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31667
> >
>
> By the way, this PR says "Integer externsions aren't vectorized" - but I
> think the testcase you are referring to does get vectorized, only not as
> efficiently as you would want it to (right?).

I was referring to extensions including things like V2QI -> V2DI.

> It
> > isn't easy to move N/2 high elemenets to N/2 low elemenets.
>
> just curious - why is it difficult? (couldn't you use a psrldq? is it too
> expensive?)

It needs more instructions.

H.J.