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

["H.J. Lu" <hjl.tools@gmail.com>]

On Fri, Oct 21, 2022 at 2:33 AM Richard Biener
<richard.guenther@gmail.com> wrote:
>
> 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

TYPE_MODE_RAW is always set to a vector mode for a vector type:

       /* Find an appropriate mode for the vector type.  */
        if (TYPE_MODE (type) == VOIDmode)
          SET_TYPE_MODE (type,
                         mode_for_vector (SCALAR_TYPE_MODE (innertype),
                                          nunits).else_blk ());

But TYPE_MODE returns BLKmode if the vector mode is unsupported.

> also be an integer mode.

For a vector field, mode is either BLK mode or the vector mode.  Jakub,
can you comment on it?

>
> >             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
> >



-- 
H.J.