[vect] Enhance NARROW FLOAT_EXPR vectorization by truncating integer to lower precision.

Similar like WIDEN FLOAT_EXPR, when direct_optab is not existed, try
intermediate integer type whenever gimple ranger can tell it's safe.

.i.e.
When there's no direct optab for vector long long -> vector float, but
the value range of integer can be represented as int, try vector int
-> vector float if availble.

Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
Ok for trunk?

gcc/ChangeLog:

	PR tree-optimization/108804
	* tree-vect-patterns.cc (vect_get_range_info): Remove static.
	* tree-vect-stmts.cc (vect_create_vectorized_demotion_stmts):
	Add new parameter last_stmt_p.
	(vectorizable_conversion): Enhance NARROW FLOAT_EXPR
	vectorization by truncating to lower precision.
	* tree-vectorizer.h (vect_get_range_info): New declare.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr108804.c: New test.
---
 gcc/testsuite/gcc.target/i386/pr108804.c |  15 ++++
 gcc/tree-vect-patterns.cc                |   2 +-
 gcc/tree-vect-stmts.cc                   | 106 ++++++++++++++++++-----
 gcc/tree-vectorizer.h                    |   1 +
 4 files changed, 100 insertions(+), 24 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr108804.c

On Wed, Apr 26, 2023 at 9:36 AM liuhongt via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Similar like WIDEN FLOAT_EXPR, when direct_optab is not existed, try
> intermediate integer type whenever gimple ranger can tell it's safe.
>
> .i.e.
> When there's no direct optab for vector long long -> vector float, but
> the value range of integer can be represented as int, try vector int
> -> vector float if availble.
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> Ok for trunk?
>
> gcc/ChangeLog:
>
>         PR tree-optimization/108804
>         * tree-vect-patterns.cc (vect_get_range_info): Remove static.
>         * tree-vect-stmts.cc (vect_create_vectorized_demotion_stmts):
>         Add new parameter last_stmt_p.
>         (vectorizable_conversion): Enhance NARROW FLOAT_EXPR
>         vectorization by truncating to lower precision.
>         * tree-vectorizer.h (vect_get_range_info): New declare.
>
> gcc/testsuite/ChangeLog:
>
>         * gcc.target/i386/pr108804.c: New test.
> ---
>  gcc/testsuite/gcc.target/i386/pr108804.c |  15 ++++
>  gcc/tree-vect-patterns.cc                |   2 +-
>  gcc/tree-vect-stmts.cc                   | 106 ++++++++++++++++++-----
>  gcc/tree-vectorizer.h                    |   1 +
>  4 files changed, 100 insertions(+), 24 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr108804.c
>
> diff --git a/gcc/testsuite/gcc.target/i386/pr108804.c b/gcc/testsuite/gcc.target/i386/pr108804.c
> new file mode 100644
> index 00000000000..2a43c1e1848
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr108804.c
> @@ -0,0 +1,15 @@
> +/* { dg-do compile } */
> +/* { dg-options "-mavx2 -Ofast -fdump-tree-vect-details" } */
> +/* { dg-final { scan-tree-dump-times "vectorized \[1-3] loops" 1 "vect" } } */
> +
> +typedef unsigned long long uint64_t;
> +uint64_t d[512];
> +float f[1024];
> +
> +void foo() {
> +    for (int i=0; i<512; ++i) {
> +        uint64_t k = d[i];
> +        f[i]=(k & 0x3F30FFFF);
> +    }
> +}
> +
> diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
> index a49b0953977..dd546b488a4 100644
> --- a/gcc/tree-vect-patterns.cc
> +++ b/gcc/tree-vect-patterns.cc
> @@ -61,7 +61,7 @@ along with GCC; see the file COPYING3.  If not see
>  /* Return true if we have a useful VR_RANGE range for VAR, storing it
>     in *MIN_VALUE and *MAX_VALUE if so.  Note the range in the dump files.  */
>
> -static bool
> +bool
>  vect_get_range_info (tree var, wide_int *min_value, wide_int *max_value)
>  {
>    value_range vr;
> diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
> index 6b7dbfd4a23..d79a1409d24 100644
> --- a/gcc/tree-vect-stmts.cc
> +++ b/gcc/tree-vect-stmts.cc
> @@ -51,6 +51,7 @@ along with GCC; see the file COPYING3.  If not see
>  #include "internal-fn.h"
>  #include "tree-vector-builder.h"
>  #include "vec-perm-indices.h"
> +#include "gimple-range.h"
>  #include "tree-ssa-loop-niter.h"
>  #include "gimple-fold.h"
>  #include "regs.h"
> @@ -4799,7 +4800,8 @@ vect_create_vectorized_demotion_stmts (vec_info *vinfo, vec<tree> *vec_oprnds,
>                                        stmt_vec_info stmt_info,
>                                        vec<tree> &vec_dsts,
>                                        gimple_stmt_iterator *gsi,
> -                                      slp_tree slp_node, enum tree_code code)
> +                                      slp_tree slp_node, enum tree_code code,
> +                                      bool last_stmt_p)

Can you please document this new parameter?

>  {
>    unsigned int i;
>    tree vop0, vop1, new_tmp, vec_dest;
> @@ -4815,9 +4817,9 @@ vect_create_vectorized_demotion_stmts (vec_info *vinfo, vec<tree> *vec_oprnds,
>        new_tmp = make_ssa_name (vec_dest, new_stmt);
>        gimple_assign_set_lhs (new_stmt, new_tmp);
>        vect_finish_stmt_generation (vinfo, stmt_info, new_stmt, gsi);
> -
> -      if (multi_step_cvt)
> -       /* Store the resulting vector for next recursive call.  */
> +      if (multi_step_cvt || !last_stmt_p)
> +       /* Store the resulting vector for next recursive call,
> +          or return the resulting vector_tmp for NARROW FLOAT_EXPR.  */
>         (*vec_oprnds)[i/2] = new_tmp;
>        else
>         {
> @@ -4843,7 +4845,8 @@ vect_create_vectorized_demotion_stmts (vec_info *vinfo, vec<tree> *vec_oprnds,
>        vect_create_vectorized_demotion_stmts (vinfo, vec_oprnds,
>                                              multi_step_cvt - 1,
>                                              stmt_info, vec_dsts, gsi,
> -                                            slp_node, VEC_PACK_TRUNC_EXPR);
> +                                            slp_node, VEC_PACK_TRUNC_EXPR,
> +                                            last_stmt_p);
>      }
>
>    vec_dsts.quick_push (vec_dest);
> @@ -5248,22 +5251,53 @@ vectorizable_conversion (vec_info *vinfo,
>                                            &interm_types))
>         break;
>
> -      if (code != FIX_TRUNC_EXPR
> -         || GET_MODE_SIZE (lhs_mode) >= GET_MODE_SIZE (rhs_mode))
> +      if (GET_MODE_SIZE (lhs_mode) >= GET_MODE_SIZE (rhs_mode))
>         goto unsupported;
>
> -      cvt_type
> -       = build_nonstandard_integer_type (GET_MODE_BITSIZE (rhs_mode), 0);
> -      cvt_type = get_same_sized_vectype (cvt_type, vectype_in);
> -      if (cvt_type == NULL_TREE)
> -       goto unsupported;
> -      if (!supportable_convert_operation (code, cvt_type, vectype_in,
> -                                         &codecvt1))
> -       goto unsupported;
> -      if (supportable_narrowing_operation (NOP_EXPR, vectype_out, cvt_type,
> -                                          &code1, &multi_step_cvt,
> -                                          &interm_types))
> -       break;
> +      if (code == FIX_TRUNC_EXPR)
> +       {
> +         cvt_type
> +           = build_nonstandard_integer_type (GET_MODE_BITSIZE (rhs_mode), 0);
> +         cvt_type = get_same_sized_vectype (cvt_type, vectype_in);
> +         if (cvt_type == NULL_TREE)
> +           goto unsupported;
> +         if (!supportable_convert_operation (code, cvt_type, vectype_in,
> +                                             &codecvt1))
> +           goto unsupported;
> +         if (supportable_narrowing_operation (NOP_EXPR, vectype_out, cvt_type,
> +                                              &code1, &multi_step_cvt,
> +                                              &interm_types))
> +           break;
> +       }
> +      /* If op0 can be represented with low precision integer,
> +        truncate it to cvt_type and the do FLOAT_EXPR.  */
> +      else if (code == FLOAT_EXPR)
> +       {
> +         wide_int op_min_value, op_max_value;
> +         if (!vect_get_range_info (op0, &op_min_value, &op_max_value))
> +           goto unsupported;
> +
> +         cvt_type
> +           = build_nonstandard_integer_type (GET_MODE_BITSIZE (lhs_mode), 0);
> +         if (cvt_type == NULL_TREE
> +             || (wi::min_precision (op_max_value, SIGNED)
> +                 > TYPE_PRECISION (cvt_type))
> +             || (wi::min_precision (op_min_value, SIGNED)
> +                 > TYPE_PRECISION (cvt_type)))
> +           goto unsupported;
> +
> +         cvt_type = get_same_sized_vectype (cvt_type, vectype_out);
> +         if (cvt_type == NULL_TREE)
> +           goto unsupported;
> +         if (!supportable_narrowing_operation (NOP_EXPR, cvt_type, vectype_in,
> +                                               &code1, &multi_step_cvt,
> +                                               &interm_types))
> +           goto unsupported;
> +         if (supportable_convert_operation (code, vectype_out,
> +                                            cvt_type, &codecvt1))
> +           break;
> +       }
> +
>        goto unsupported;
>
>      default:
> @@ -5335,8 +5369,11 @@ vectorizable_conversion (vec_info *vinfo,
>       from supportable_*_operation, and store them in the correct order
>       for future use in vect_create_vectorized_*_stmts ().  */
>    auto_vec<tree> vec_dsts (multi_step_cvt + 1);
> +  bool widen_or_narrow_float_p
> +    = cvt_type && (modifier == WIDEN
> +                  || (modifier == NARROW && code == FLOAT_EXPR));
>    vec_dest = vect_create_destination_var (scalar_dest,
> -                                         (cvt_type && modifier == WIDEN)
> +                                         widen_or_narrow_float_p
>                                           ? cvt_type : vectype_out);
>    vec_dsts.quick_push (vec_dest);
>
> @@ -5353,7 +5390,7 @@ vectorizable_conversion (vec_info *vinfo,
>
>    if (cvt_type)
>      vec_dest = vect_create_destination_var (scalar_dest,
> -                                           modifier == WIDEN
> +                                           widen_or_narrow_float_p
>                                             ? vectype_out : cvt_type);
>
>    int ninputs = 1;
> @@ -5456,7 +5493,7 @@ vectorizable_conversion (vec_info *vinfo,
>        vect_get_vec_defs (vinfo, stmt_info, slp_node, ncopies * ninputs,
>                          op0, &vec_oprnds0);
>        /* Arguments are ready.  Create the new vector stmts.  */
> -      if (cvt_type)
> +      if (cvt_type && code != FLOAT_EXPR)
>         FOR_EACH_VEC_ELT (vec_oprnds0, i, vop0)
>           {
>             gcc_assert (TREE_CODE_LENGTH (codecvt1) == unary_op);
> @@ -5470,7 +5507,30 @@ vectorizable_conversion (vec_info *vinfo,
>        vect_create_vectorized_demotion_stmts (vinfo, &vec_oprnds0,
>                                              multi_step_cvt,
>                                              stmt_info, vec_dsts, gsi,
> -                                            slp_node, code1);
> +                                            slp_node, code1,
> +                                            !cvt_type || code != FLOAT_EXPR);

I understand what you are doing, but somehow it looks a bit awkward?
Maybe we should split the NARROW case into NARROW_SRC and NARROW_DST?
The case of narrowing the source because we know its range isn't a
good fit for the
flow.

> +      /* After demoting op0 to cvt_type, convert it to dest.  */
> +      if (cvt_type && code == FLOAT_EXPR)
> +       {
> +         for (unsigned int i = 0; i != vec_oprnds0.length() / 2;  i++)
> +           {
> +             /* Arguments are ready, create the new vector stmt.  */
> +             gcc_assert (TREE_CODE_LENGTH (codecvt1) == unary_op);
> +             gassign *new_stmt
> +               = gimple_build_assign (vec_dest, codecvt1, vec_oprnds0[i]);
> +             new_temp = make_ssa_name (vec_dest, new_stmt);
> +             gimple_assign_set_lhs (new_stmt, new_temp);
> +             vect_finish_stmt_generation (vinfo, stmt_info, new_stmt, gsi);
> +
> +             /* This is the last step of the conversion sequence. Store the
> +                vectors in SLP_NODE or in vector info of the scalar statement
> +                (or in STMT_VINFO_RELATED_STMT chain).  */
> +             if (slp_node)
> +               SLP_TREE_VEC_STMTS (slp_node).quick_push (new_stmt);
> +             else
> +               STMT_VINFO_VEC_STMTS (stmt_info).safe_push (new_stmt);
> +           }
> +       }
>        break;
>      }
>    if (!slp_node)
> diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
> index 9cf2fb23fe3..27fa2306a5e 100644
> --- a/gcc/tree-vectorizer.h
> +++ b/gcc/tree-vectorizer.h
> @@ -2384,6 +2384,7 @@ extern bool compatible_calls_p (gcall *, gcall *);
>  /* In tree-vect-patterns.cc.  */
>  extern void
>  vect_mark_pattern_stmts (vec_info *, stmt_vec_info, gimple *, tree);
> +extern bool vect_get_range_info (tree, wide_int*, wide_int*);
>
>  /* Pattern recognition functions.
>     Additional pattern recognition functions can (and will) be added
> --
> 2.39.1.388.g2fc9e9ca3c
>