On Wed, Jun 26, 2019 at 10:36 AM Richard Biener <rguent...@suse.de> wrote:
>
> On June 26, 2019 10:25:44 AM GMT+02:00, Uros Bizjak <ubiz...@gmail.com> wrote:
> >On Wed, Jun 26, 2019 at 10:17 AM Uros Bizjak <ubiz...@gmail.com> wrote:
> >>
> >> Now that TARGET_MMX_WITH_SSE is implemented, the compiler should be
> >> able to auto-vectorize:
> >
> >On a related note, following slightly changed testcase:
> >
> >void
> >foo (char *restrict r, char *restrict a)
> >{
> > for (int i = 0; i < 24; i++)
> > r[i] += a[i];
> >}
> >
> >compiles to:
> >
> >foo:
> > vmovdqu (%rdi), %xmm1
> > vpaddb (%rsi), %xmm1, %xmm0
> > movzbl 16(%rsi), %eax
> > addb %al, 16(%rdi)
> > vmovups %xmm0, (%rdi)
> > movzbl 17(%rsi), %eax
> > addb %al, 17(%rdi)
> > movzbl 18(%rsi), %eax
> > addb %al, 18(%rdi)
> > movzbl 19(%rsi), %eax
> > addb %al, 19(%rdi)
> > movzbl 20(%rsi), %eax
> > addb %al, 20(%rdi)
> > movzbl 21(%rsi), %eax
> > addb %al, 21(%rdi)
> > movzbl 22(%rsi), %eax
> > addb %al, 22(%rdi)
> > movzbl 23(%rsi), %eax
> > addb %al, 23(%rdi)
> > ret
> >
> >One would expect that the remaining 8-byte array would also get
> >vectorized, resulting in one 16-byte operation and one 8-byte
> >operation.
>
> Try - - param vect-epilogue-nomask=1 (or so).
Yes, this (--param vect-epilogues-nomask=1) works!
foo:
movdqu (%rdi), %xmm0
movdqu (%rsi), %xmm2
movq 16(%rsi), %xmm1
paddb %xmm2, %xmm0
movups %xmm0, (%rdi)
movq 16(%rdi), %xmm0
paddb %xmm1, %xmm0
movq %xmm0, 16(%rdi)
ret
Thanks,
Uros.
