Re: [9b/n] PR85694: Make vect_is_simple_use look through pattern statements

[Richard Biener <richard dot guenther at gmail dot com>]

On Wed, Jun 27, 2018 at 11:34 AM Richard Sandiford
<richard.sandiford@arm.com> wrote:
>
> Richard Sandiford <richard.sandiford@arm.com> writes:
> > Richard Biener <richard.guenther@gmail.com> writes:
> >> On Mon, Jun 18, 2018 at 5:04 PM Richard Sandiford
> >> <richard.sandiford@arm.com> wrote:
> >>>
> >>> When following the definitions of SSA names, some recognisers
> >>> already cope with statements that have been replaced by patterns.
> >>> This patch makes that happen automatically for users of
> >>> type_conversion_p and vect_get_internal_def.  It also adds
> >>> a vect_look_through_pattern helper that can be used directly.
> >>>
> >>> The reason for doing this is that the main patch for PR85694
> >>> makes over_widening handle more general cases.  These over-widened
> >>> patterns can still be useful when matching later statements;
> >>> e.g. an overwidened MULT_EXPR could be the input to a DOT_PROD_EXPR.
> >>>
> >>> The patch doesn't do anything with the STMT_VINFO_IN_PATTERN_P checks
> >>> in vect_recog_over_widening_pattern or vect_recog_widen_shift_pattern
> >>> since later patches rewrite them anyway.
> >>>
> >>> Doing this fixed an XFAIL in vect-reduc-dot-u16b.c.
> >>>
> >>> Tested on aarch64-linux-gnu and x86_64-linux-gnu.  OK to install?
> >>
> >> Hmm.  It seems to me that *def_stmt for vect_is_simple_use should
> >> eventually be the pattern def given the vectype overload takes the
> >> vectype from the pattern def already but oddly enough the
> >> DEF_TYPE is taken from the non-pattern stmt.
> >>
> >> I wonder which callers look at def_stmt at all (and how...)
> >>
> >> I guess swapping the def_stmt and dt arguments and adding yet another
> >> overload to remove all unused &def_stmt args might this easier to review...
> >>
> >> So - I'm suggesting to change vect_is_simple_use.
> >
> > OK, I'll try that.  Might end up being its own mini-series. :-)
>
> And here's the second and final part: make vect_is_simple_use check
> whether a defining statement has been replaced by a pattern statement,
> and if so return the pattern statement instead.
>
> Tested on aarch64-linux-gnu and x86_64-linux-gnu.  OK to install?

OK.

Thanks,
Richard.

> Richard
>
>
> 2018-06-14  Richard Sandiford  <richard.sandiford@arm.com>
>
> gcc/
>         * tree-vect-loop.c (vectorizable_reduction): Assert that the
>         phi is not a pattern statement and has not been replaced by
>         a pattern statement.
>         * tree-vect-patterns.c (type_conversion_p): Don't check
>         STMT_VINFO_IN_PATTERN_P.
>         (vect_recog_vector_vector_shift_pattern): Likewise.
>         (vect_recog_dot_prod_pattern): Expect vect_is_simple_use to return
>         the pattern statement rather than the original statement; check
>         directly for a WIDEN_MULT_EXPR here.
>         * tree-vect-slp.c (vect_get_and_check_slp_defs): Expect
>         vect_is_simple_use to return the pattern statement rather
>         than the original statement; use is_pattern_stmt_p to check
>         for such a pattern statement.
>         * tree-vect-stmts.c (process_use): Expect vect_is_simple_use
>         to return the pattern statement rather than the original statement;
>         don't do the same transformation here.
>         (vect_is_simple_use): If the defining statement has been replaced
>         by a pattern statement, return the pattern statement instead.
>         Remove the corresponding (local) transformation from the vectype
>         overload.
>
> gcc/testsuite/
>         * gcc.dg/vect/vect-reduc-dot-u16b.c: Remove xfail and update the
>         test for vectorization along the lines described in the comment.
>
> Index: gcc/tree-vect-loop.c
> ===================================================================
> --- gcc/tree-vect-loop.c        2018-06-27 10:27:31.782458413 +0100
> +++ gcc/tree-vect-loop.c        2018-06-27 10:27:34.490434751 +0100
> @@ -6482,6 +6482,8 @@ vectorizable_reduction (gimple *stmt, gi
>      }
>
>    stmt_vec_info reduc_def_info = vinfo_for_stmt (reduc_def_stmt);
> +  /* PHIs should not participate in patterns.  */
> +  gcc_assert (!STMT_VINFO_RELATED_STMT (reduc_def_info));
>    enum vect_reduction_type v_reduc_type
>      = STMT_VINFO_REDUC_TYPE (reduc_def_info);
>    gimple *tmp = STMT_VINFO_REDUC_DEF (reduc_def_info);
> Index: gcc/tree-vect-patterns.c
> ===================================================================
> --- gcc/tree-vect-patterns.c    2018-06-27 10:27:31.782458413 +0100
> +++ gcc/tree-vect-patterns.c    2018-06-27 10:27:34.490434751 +0100
> @@ -193,13 +193,6 @@ type_conversion_p (tree name, gimple *us
>    if (!*def_stmt)
>      return false;
>
> -  if (dt == vect_internal_def)
> -    {
> -      stmt_vec_info def_vinfo = vinfo_for_stmt (*def_stmt);
> -      if (STMT_VINFO_IN_PATTERN_P (def_vinfo))
> -       return false;
> -    }
> -
>    if (!is_gimple_assign (*def_stmt))
>      return false;
>
> @@ -383,20 +376,11 @@ vect_recog_dot_prod_pattern (vec<gimple
>    /* FORNOW.  Can continue analyzing the def-use chain when this stmt in a phi
>       inside the loop (in case we are analyzing an outer-loop).  */
>    gassign *mult = dyn_cast <gassign *> (mult_vinfo->stmt);
> -  if (!mult || gimple_assign_rhs_code (mult) != MULT_EXPR)
> +  if (!mult)
>      return NULL;
> -  if (STMT_VINFO_IN_PATTERN_P (mult_vinfo))
> +  if (gimple_assign_rhs_code (mult) == WIDEN_MULT_EXPR)
>      {
>        /* Has been detected as a widening multiplication?  */
> -
> -      mult = dyn_cast <gassign *> (STMT_VINFO_RELATED_STMT (mult_vinfo));
> -      if (!mult || gimple_assign_rhs_code (mult) != WIDEN_MULT_EXPR)
> -        return NULL;
> -      STMT_VINFO_PATTERN_DEF_SEQ (stmt_vinfo)
> -       = STMT_VINFO_PATTERN_DEF_SEQ (mult_vinfo);
> -      mult_vinfo = vinfo_for_stmt (mult);
> -      gcc_assert (mult_vinfo);
> -      gcc_assert (STMT_VINFO_DEF_TYPE (mult_vinfo) == vect_internal_def);
>        oprnd00 = gimple_assign_rhs1 (mult);
>        oprnd01 = gimple_assign_rhs2 (mult);
>      }
> @@ -406,6 +390,9 @@ vect_recog_dot_prod_pattern (vec<gimple
>        gimple *def_stmt;
>        tree oprnd0, oprnd1;
>
> +      if (gimple_assign_rhs_code (mult) != MULT_EXPR)
> +       return NULL;
> +
>        oprnd0 = gimple_assign_rhs1 (mult);
>        oprnd1 = gimple_assign_rhs2 (mult);
>        if (!type_conversion_p (oprnd0, mult, true, &half_type0, &def_stmt,
> @@ -2050,9 +2037,7 @@ vect_recog_vector_vector_shift_pattern (
>
>    tree def = NULL_TREE;
>    gassign *def_stmt = dyn_cast <gassign *> (def_vinfo->stmt);
> -  if (!STMT_VINFO_IN_PATTERN_P (def_vinfo)
> -      && def_stmt
> -      && gimple_assign_cast_p (def_stmt))
> +  if (def_stmt && gimple_assign_cast_p (def_stmt))
>      {
>        tree rhs1 = gimple_assign_rhs1 (def_stmt);
>        if (TYPE_MODE (TREE_TYPE (rhs1)) == TYPE_MODE (TREE_TYPE (oprnd0))
> Index: gcc/tree-vect-slp.c
> ===================================================================
> --- gcc/tree-vect-slp.c 2018-06-27 10:27:31.782458413 +0100
> +++ gcc/tree-vect-slp.c 2018-06-27 10:27:34.490434751 +0100
> @@ -365,11 +365,9 @@ vect_get_and_check_slp_defs (vec_info *v
>           from the pattern.  Check that all the stmts of the node are in the
>           pattern.  */
>        if (def_stmt && gimple_bb (def_stmt)
> -          && vect_stmt_in_region_p (vinfo, def_stmt)
> -          && vinfo_for_stmt (def_stmt)
> -          && STMT_VINFO_IN_PATTERN_P (vinfo_for_stmt (def_stmt))
> -         && !STMT_VINFO_RELEVANT (vinfo_for_stmt (def_stmt))
> -         && !STMT_VINFO_LIVE_P (vinfo_for_stmt (def_stmt)))
> +         && vect_stmt_in_region_p (vinfo, def_stmt)
> +         && vinfo_for_stmt (def_stmt)
> +         && is_pattern_stmt_p (vinfo_for_stmt (def_stmt)))
>          {
>            pattern = true;
>            if (!first && !oprnd_info->first_pattern
> @@ -398,7 +396,6 @@ vect_get_and_check_slp_defs (vec_info *v
>               return 1;
>              }
>
> -          def_stmt = STMT_VINFO_RELATED_STMT (vinfo_for_stmt (def_stmt));
>            dt = STMT_VINFO_DEF_TYPE (vinfo_for_stmt (def_stmt));
>
>            if (dt == vect_unknown_def_type)
> Index: gcc/tree-vect-stmts.c
> ===================================================================
> --- gcc/tree-vect-stmts.c       2018-06-27 10:27:31.782458413 +0100
> +++ gcc/tree-vect-stmts.c       2018-06-27 10:27:34.490434751 +0100
> @@ -506,8 +506,6 @@ process_use (gimple *stmt, tree use, loo
>        if (dump_enabled_p ())
>         dump_printf_loc (MSG_NOTE, vect_location,
>                           "reduc-stmt defining reduc-phi in the same nest.\n");
> -      if (STMT_VINFO_IN_PATTERN_P (dstmt_vinfo))
> -       dstmt_vinfo = vinfo_for_stmt (STMT_VINFO_RELATED_STMT (dstmt_vinfo));
>        gcc_assert (STMT_VINFO_RELEVANT (dstmt_vinfo) < vect_used_by_reduction);
>        gcc_assert (STMT_VINFO_LIVE_P (dstmt_vinfo)
>                   || STMT_VINFO_RELEVANT (dstmt_vinfo) > vect_unused_in_scope);
> @@ -10069,8 +10067,6 @@ vect_is_simple_use (tree operand, vec_in
>      }
>
>    gimple *def_stmt = SSA_NAME_DEF_STMT (operand);
> -  if (def_stmt_out)
> -    *def_stmt_out = def_stmt;
>    if (dump_enabled_p ())
>      {
>        dump_printf_loc (MSG_NOTE, vect_location, "def_stmt: ");
> @@ -10082,8 +10078,15 @@ vect_is_simple_use (tree operand, vec_in
>    else
>      {
>        stmt_vec_info stmt_vinfo = vinfo_for_stmt (def_stmt);
> +      if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo))
> +       {
> +         def_stmt = STMT_VINFO_RELATED_STMT (stmt_vinfo);
> +         stmt_vinfo = vinfo_for_stmt (def_stmt);
> +       }
>        *dt = STMT_VINFO_DEF_TYPE (stmt_vinfo);
>      }
> +  if (def_stmt_out)
> +    *def_stmt_out = def_stmt;
>
>    if (dump_enabled_p ())
>      {
> @@ -10174,12 +10177,6 @@ vect_is_simple_use (tree operand, vec_in
>        || *dt == vect_nested_cycle)
>      {
>        stmt_vec_info stmt_info = vinfo_for_stmt (def_stmt);
> -
> -      if (STMT_VINFO_IN_PATTERN_P (stmt_info)
> -          && !STMT_VINFO_RELEVANT (stmt_info)
> -          && !STMT_VINFO_LIVE_P (stmt_info))
> -       stmt_info = vinfo_for_stmt (STMT_VINFO_RELATED_STMT (stmt_info));
> -
>        *vectype = STMT_VINFO_VECTYPE (stmt_info);
>        gcc_assert (*vectype != NULL_TREE);
>      }
> Index: gcc/testsuite/gcc.dg/vect/vect-reduc-dot-u16b.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/vect/vect-reduc-dot-u16b.c     2018-06-27 10:27:12.366628072 +0100
> +++ gcc/testsuite/gcc.dg/vect/vect-reduc-dot-u16b.c     2018-06-27 10:27:34.490434751 +0100
> @@ -10,11 +10,8 @@ #define DOT2 43680
>  unsigned short X[N] __attribute__ ((__aligned__(__BIGGEST_ALIGNMENT__)));
>  unsigned short Y[N] __attribute__ ((__aligned__(__BIGGEST_ALIGNMENT__)));
>
> -/* short->int->int dot product.
> -   Currently not detected as a dot-product pattern: the multiplication
> -   promotes the ushorts to int, and then the product is promoted to unsigned
> -   int for the addition.  Which results in an int->unsigned int cast, which
> -   since no bits are modified in the cast should be trivially vectorizable.  */
> +/* ushort->int->uint dot product: the multiplication promotes the ushorts
> +   to int, and then the product is converted to uint for the addition.  */
>  __attribute__ ((noinline)) unsigned int
>  foo2(int len) {
>    int i;
> @@ -47,12 +44,6 @@ int main (void)
>    return 0;
>  }
>
> -/* { dg-final { scan-tree-dump-times "vect_recog_dot_prod_pattern: detected" 1 "vect" { xfail *-*-* } } } */
> -
> -/* Once the dot-product pattern is detected, we expect
> -   that loop to be vectorized on vect_udot_hi targets (targets that support
> -   dot-product of unsigned shorts) and targets that support widening multiplication.  */
> -/* The induction loop in main is vectorized.  */
> -/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 2 "vect" { xfail *-*-* } } } */
> -/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target vect_pack_trunc } } } */
> +/* { dg-final { scan-tree-dump-times "vect_recog_dot_prod_pattern: detected" 1 "vect" } } */
>
> +/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target { vect_pack_trunc || vect_udot_hi } } } } */