Re: [SVE] Fold svdupq to VEC_PERM_EXPR if elements are not constant

[Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org>]

On Wed, 28 Jun 2023 at 00:05, Richard Sandiford
<richard.sandiford@arm.com> wrote:
>
> Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org> writes:
> > Hi Richard,
> > Sorry I forgot to commit this patch, which you had approved in:
> > https://gcc.gnu.org/pipermail/gcc-patches/2023-April/615308.html
> >
> > Just for context for the following test:
> > svint32_t f_s32(int32x4_t x)
> > {
> >   return svdupq_s32 (x[0], x[1], x[2], x[3]);
> > }
> >
> > -O3 -mcpu=generic+sve generates following code after interleave+zip1 patch:
> > f_s32:
> >         dup     s31, v0.s[1]
> >         mov     v30.8b, v0.8b
> >         ins     v31.s[1], v0.s[3]
> >         ins     v30.s[1], v0.s[2]
> >         zip1    v0.4s, v30.4s, v31.4s
> >         dup     z0.q, z0.q[0]
> >         ret
> >
> > Code-gen with attached patch:
> > f_s32:
> >         dup     z0.q, z0.q[0]
> >         ret
> >
> > Bootstrapped+tested on aarch64-linux-gnu.
> > OK to commit ?
> >
> > Thanks,
> > Prathamesh
> >
> > [SVE] Fold svdupq to VEC_PERM_EXPR if elements are not constant.
> >
> > gcc/ChangeLog:
> >         * config/aarch64/aarch64-sve-builtins-base.cc
> >         (svdupq_impl::fold_nonconst_dupq): New method.
> >         (svdupq_impl::fold): Call fold_nonconst_dupq.
> >
> > gcc/testsuite/ChangeLog:
> >         * gcc.target/aarch64/sve/acle/general/dupq_11.c: New test.
>
> OK, thanks.
Thanks, pushed to trunk in 231f6b56c77c50f337f2529b3ae51e2083ce461d

Thanks,
Prathamesh
>
> Richard
>
> > diff --git a/gcc/config/aarch64/aarch64-sve-builtins-base.cc b/gcc/config/aarch64/aarch64-sve-builtins-base.cc
> > index 95b4cb8a943..9010ecca6da 100644
> > --- a/gcc/config/aarch64/aarch64-sve-builtins-base.cc
> > +++ b/gcc/config/aarch64/aarch64-sve-builtins-base.cc
> > @@ -817,6 +817,52 @@ public:
> >
> >  class svdupq_impl : public quiet<function_base>
> >  {
> > +private:
> > +  gimple *
> > +  fold_nonconst_dupq (gimple_folder &f) const
> > +  {
> > +    /* Lower lhs = svdupq (arg0, arg1, ..., argN} into:
> > +       tmp = {arg0, arg1, ..., arg<N-1>}
> > +       lhs = VEC_PERM_EXPR (tmp, tmp, {0, 1, 2, N-1, ...})  */
> > +
> > +    if (f.type_suffix (0).bool_p
> > +     || BYTES_BIG_ENDIAN)
> > +      return NULL;
> > +
> > +    tree lhs = gimple_call_lhs (f.call);
> > +    tree lhs_type = TREE_TYPE (lhs);
> > +    tree elt_type = TREE_TYPE (lhs_type);
> > +    scalar_mode elt_mode = SCALAR_TYPE_MODE (elt_type);
> > +    machine_mode vq_mode = aarch64_vq_mode (elt_mode).require ();
> > +    tree vq_type = build_vector_type_for_mode (elt_type, vq_mode);
> > +
> > +    unsigned nargs = gimple_call_num_args (f.call);
> > +    vec<constructor_elt, va_gc> *v;
> > +    vec_alloc (v, nargs);
> > +    for (unsigned i = 0; i < nargs; i++)
> > +      CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, gimple_call_arg (f.call, i));
> > +    tree vec = build_constructor (vq_type, v);
> > +    tree tmp = make_ssa_name_fn (cfun, vq_type, 0);
> > +    gimple *g = gimple_build_assign (tmp, vec);
> > +
> > +    gimple_seq stmts = NULL;
> > +    gimple_seq_add_stmt_without_update (&stmts, g);
> > +
> > +    poly_uint64 lhs_len = TYPE_VECTOR_SUBPARTS (lhs_type);
> > +    vec_perm_builder sel (lhs_len, nargs, 1);
> > +    for (unsigned i = 0; i < nargs; i++)
> > +      sel.quick_push (i);
> > +
> > +    vec_perm_indices indices (sel, 1, nargs);
> > +    tree mask_type = build_vector_type (ssizetype, lhs_len);
> > +    tree mask = vec_perm_indices_to_tree (mask_type, indices);
> > +
> > +    gimple *g2 = gimple_build_assign (lhs, VEC_PERM_EXPR, tmp, tmp, mask);
> > +    gimple_seq_add_stmt_without_update (&stmts, g2);
> > +    gsi_replace_with_seq (f.gsi, stmts, false);
> > +    return g2;
> > +  }
> > +
> >  public:
> >    gimple *
> >    fold (gimple_folder &f) const override
> > @@ -832,7 +878,7 @@ public:
> >        {
> >       tree elt = gimple_call_arg (f.call, i);
> >       if (!CONSTANT_CLASS_P (elt))
> > -       return NULL;
> > +       return fold_nonconst_dupq (f);
> >       builder.quick_push (elt);
> >       for (unsigned int j = 1; j < factor; ++j)
> >         builder.quick_push (build_zero_cst (TREE_TYPE (vec_type)));
> > diff --git a/gcc/testsuite/gcc.target/aarch64/sve/acle/general/dupq_11.c b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/dupq_11.c
> > new file mode 100644
> > index 00000000000..f19f8deb1e5
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/dupq_11.c
> > @@ -0,0 +1,31 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O3 -fdump-tree-optimized" } */
> > +
> > +#include <arm_sve.h>
> > +#include <arm_neon.h>
> > +
> > +svint8_t f_s8(int8x16_t x)
> > +{
> > +  return svdupq_s8 (x[0], x[1], x[2], x[3], x[4], x[5], x[6], x[7],
> > +                 x[8], x[9], x[10], x[11], x[12], x[13], x[14], x[15]);
> > +}
> > +
> > +svint16_t f_s16(int16x8_t x)
> > +{
> > +  return svdupq_s16 (x[0], x[1], x[2], x[3], x[4], x[5], x[6], x[7]);
> > +}
> > +
> > +svint32_t f_s32(int32x4_t x)
> > +{
> > +  return svdupq_s32 (x[0], x[1], x[2], x[3]);
> > +}
> > +
> > +svint64_t f_s64(int64x2_t x)
> > +{
> > +  return svdupq_s64 (x[0], x[1]);
> > +}
> > +
> > +/* { dg-final { scan-tree-dump "VEC_PERM_EXPR" "optimized" } } */
> > +/* { dg-final { scan-tree-dump-not "svdupq" "optimized" } } */
> > +
> > +/* { dg-final { scan-assembler-times {\tdup\tz[0-9]+\.q, z[0-9]+\.q\[0\]\n} 4 } } */