Re: [PATCH] Fix vec_concatv2di pattern for SSE4 (PR target/80819)

[Uros Bizjak <ubizjak@gmail.com>]

On Wed, Nov 29, 2017 at 9:24 AM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> Before r218303 we had just (=x,0,rm) alternative for SSE4 (no AVX),
> that change turned it into (=Yr,0,*rm) and (=*x,0,rm) alternatives,
> so that we avoid too many prefixes if possible.
> The latter alternative is fine, we want the *, because that is the point,
> Yr class is the subset of x registers that don't need the REX prefix.
> The * in the first alternative makes no sense, with it IRA is effectively
> forced to allocate the second vec_concat pseudo into NO_REGS - memory,
> and while postreload can fix it up afterwards, we end up with dead stores
> that nothing ever removes afterwards.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?
>
> 2017-11-29  Jakub Jelinek  <jakub@redhat.com>
>
>         PR target/80819
>         * config/i386/sse.md (vec_concatv2di): Remove * from (=Yr,0,*rm)
>         alternative.
>
>         * gcc.target/i386/pr80819-1.c: New test.
>         * gcc.target/i386/pr80819-2.c: New test.

OK.

Thanks,
Uros.

> --- gcc/config/i386/sse.md.jj   2017-11-24 08:58:05.000000000 +0100
> +++ gcc/config/i386/sse.md      2017-11-28 18:04:20.739396199 +0100
> @@ -13915,7 +13915,7 @@ (define_insn "vec_concatv2di"
>           (match_operand:DI 1 "nonimmediate_operand"
>           "  0, 0,x ,Yv,r ,vm,?!*Yn,0,Yv,0,0,v")
>           (match_operand:DI 2 "vector_move_operand"
> -         "*rm,rm,rm,rm,C ,C ,C ,x,Yv,x,m,m")))]
> +         " rm,rm,rm,rm,C ,C ,C ,x,Yv,x,m,m")))]
>    "TARGET_SSE"
>    "@
>     pinsrq\t{$1, %2, %0|%0, %2, 1}
> --- gcc/testsuite/gcc.target/i386/pr80819-1.c.jj        2017-11-28 18:11:09.452482042 +0100
> +++ gcc/testsuite/gcc.target/i386/pr80819-1.c   2017-11-28 18:09:57.000000000 +0100
> @@ -0,0 +1,13 @@
> +/* PR target/80819 */
> +/* { dg-do compile { target { ! ia32 } } } */
> +/* { dg-options "-O2 -msse4 -mno-avx -mtune=haswell -masm=att" } */
> +
> +typedef unsigned long long V __attribute__((vector_size (16)));
> +
> +V
> +foo (unsigned long long x, unsigned long long y)
> +{
> +  return (V) { x, y };
> +}
> +
> +/* { dg-final { scan-assembler-not "movq\[ \t]*%rsi, \[-0-9]*\\(" } } */
> --- gcc/testsuite/gcc.target/i386/pr80819-2.c.jj        2017-11-28 18:11:15.942404034 +0100
> +++ gcc/testsuite/gcc.target/i386/pr80819-2.c   2017-11-28 18:11:21.915332239 +0100
> @@ -0,0 +1,13 @@
> +/* PR target/80819 */
> +/* { dg-do compile { target { ! ia32 } } } */
> +/* { dg-options "-O2 -msse4 -mno-avx -mtune=generic -masm=att" } */
> +
> +typedef unsigned long long V __attribute__((vector_size (16)));
> +
> +V
> +foo (unsigned long long x, unsigned long long y)
> +{
> +  return (V) { x, y };
> +}
> +
> +/* { dg-final { scan-assembler-not "movq\[ \t]*%rsi, \[-0-9]*\\(" } } */
>
>         Jakub