On Mon, 21 Mar 2005, Uros Bizjak wrote:
> Hello!
>
> >typedef float v4sf __attribute__((vector_size(16)));
> >void foo(v4sf *a, v4sf *b, v4sf *c)
> >{
> > *a = *b + *c;
> >}
> >
> >we no longer (since 4.0) synthesize v2sf (aka sse) operations
> >for f.i. -march=athlon (not that we were too successful at this
> >in 3.4 - we generated horrible code instead). Instead for !sse2
> >architectures we generate standard i387 FP code (with some
> >unnecessary temporaries, but reasonably well).
> >
> >
> >
> SSE _is_ v4sf. 'gcc -O2 -msse -S -fomit-frame-pointer' produces:
>
> foo:
> movl 12(%esp), %eax
> movaps (%eax), %xmm0
> movl 8(%esp), %eax
> addps (%eax), %xmm0
> movl 4(%esp), %eax
> movaps %xmm0, (%eax)
> ret
>
> SSE2 is v2df.
>
> Athlon does not handle SSE insns.
Oh, so we used to expand to 3dnow? I see with gcc 3.4 produced:
foo:
pushl %ebp
movl %esp, %ebp
pushl %ebx
subl $84, %esp
movl 12(%ebp), %eax
movl 16(%ebp), %edx
[...]
movq -64(%ebp), %mm0
movl %ebx, -72(%ebp)
movl -36(%ebp), %ebx
movl %ebx, -68(%ebp)
pfadd -72(%ebp), %mm0
movq %mm0, -56(%ebp)
movl 12(%eax), %eax
etc.
This doesn't happen anymore with 4.0/4.1.
Richard.
--
Richard Guenther <richard dot guenther at uni-tuebingen dot de>
WWW: http://www.tat.physik.uni-tuebingen.de/~rguenth/
