Re: [PATCH] Always use TYPE_MODE instead of DECL_MODE for vector field

[Richard Biener <richard.guenther@gmail.com>]

On Thu, Oct 20, 2022 at 6:58 PM H.J. Lu via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> commit e034c5c895722e0092d2239cd8c2991db77d6d39
> Author: Jakub Jelinek <jakub@redhat.com>
> Date:   Sat Dec 2 08:54:47 2017 +0100
>
>         PR target/78643
>         PR target/80583
>         * expr.c (get_inner_reference): If DECL_MODE of a non-bitfield
>         is BLKmode for vector field with vector raw mode, use TYPE_MODE
>         instead of DECL_MODE.
>
> fixed the case where DECL_MODE of a vector field is BLKmode and its
> TYPE_MODE is a vector mode because of target attribute.  Remove the
> BLKmode check for the case where DECL_MODE of a vector field is a vector
> mode and its TYPE_MODE is BLKmode because of target attribute.
>
> gcc/
>
>         PR target/107304
>         * expr.c (get_inner_reference): Always use TYPE_MODE for vector
>         field with vector raw mode.
>
> gcc/testsuite/
>
>         PR target/107304
>         * gcc.target/i386/pr107304.c: New test.
> ---
>  gcc/expr.cc                              |  3 +-
>  gcc/testsuite/gcc.target/i386/pr107304.c | 39 ++++++++++++++++++++++++
>  2 files changed, 40 insertions(+), 2 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr107304.c
>
> diff --git a/gcc/expr.cc b/gcc/expr.cc
> index efe387e6173..9145193c2c1 100644
> --- a/gcc/expr.cc
> +++ b/gcc/expr.cc
> @@ -7905,8 +7905,7 @@ get_inner_reference (tree exp, poly_int64_pod *pbitsize,
>           /* For vector fields re-check the target flags, as DECL_MODE
>              could have been set with different target flags than
>              the current function has.  */
> -         if (mode == BLKmode
> -             && VECTOR_TYPE_P (TREE_TYPE (field))
> +         if (VECTOR_TYPE_P (TREE_TYPE (field))
>               && VECTOR_MODE_P (TYPE_MODE_RAW (TREE_TYPE (field))))

Isn't the check on TYPE_MODE_RAW also wrong then?  Btw, the mode could
also be an integer mode.

>             mode = TYPE_MODE (TREE_TYPE (field));
>         }
> diff --git a/gcc/testsuite/gcc.target/i386/pr107304.c b/gcc/testsuite/gcc.target/i386/pr107304.c
> new file mode 100644
> index 00000000000..24d68795e7f
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr107304.c
> @@ -0,0 +1,39 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -march=tigerlake" } */
> +
> +#include <stdint.h>
> +
> +typedef union {
> +  uint8_t v __attribute__((aligned(256))) __attribute__ ((vector_size(64 * sizeof(uint8_t))));
> +  uint8_t i[64] __attribute__((aligned(256)));
> +} stress_vec_u8_64_t;
> +
> +typedef struct {
> + struct {
> +  stress_vec_u8_64_t s;
> +  stress_vec_u8_64_t o;
> +  stress_vec_u8_64_t mask1;
> +  stress_vec_u8_64_t mask2;
> + } u8_64;
> +} stress_vec_data_t;
> +
> +__attribute__((target_clones("arch=alderlake", "default")))
> +void
> +stress_vecshuf_u8_64(stress_vec_data_t *data)
> +{
> +  stress_vec_u8_64_t *__restrict s;
> +  stress_vec_u8_64_t *__restrict mask1;
> +  stress_vec_u8_64_t *__restrict mask2;
> +  register int i;
> +
> +  s = &data->u8_64.s;
> +  mask1 = &data->u8_64.mask1;
> +  mask2 = &data->u8_64.mask2;
> +
> +  for (i = 0; i < 256; i++) {  /* was i < 65536 */
> +      stress_vec_u8_64_t tmp;
> +
> +      tmp.v = __builtin_shuffle(s->v, mask1->v);
> +      s->v = __builtin_shuffle(tmp.v, mask2->v);
> +  }
> +}
> --
> 2.37.3
>