[PATCH] [pass_if_conversion] Extend is_cond_scalar_reduction to handle bit_and/bit_xor/bit_ior.

Hongtao Liu crazylht@gmail.com
Wed Nov 10 07:26:57 GMT 2021


On Tue, Nov 9, 2021 at 6:22 PM Richard Biener via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> On Tue, Nov 9, 2021 at 3:09 AM liuhongt <hongtao.liu@intel.com> wrote:
> >
> > This will enable transformation like
> >
> > -  # sum1_50 = PHI <prephitmp_64(13), 0(4)>
> > -  # sum2_52 = PHI <sum2_21(13), 0(4)>
> > +  # sum1_50 = PHI <_87(13), 0(4)>
> > +  # sum2_52 = PHI <_89(13), 0(4)>
> >    # ivtmp_62 = PHI <ivtmp_61(13), 64(4)>
> >    i.2_7 = (long unsigned int) i_49;
> >    _8 = i.2_7 * 8;
> > ...
> >    vec1_i_38 = vec1_29 >> _10;
> >    vec2_i_39 = vec2_31 >> _10;
> >    _11 = vec1_i_38 & 1;
> > -  _63 = tmp_37 ^ sum1_50;
> > -  prephitmp_64 = _11 == 0 ? sum1_50 : _63;
> > +  _ifc__86 = _11 != 0 ? tmp_37 : 0;
> > +  _87 = sum1_50 ^ _ifc__86;
> >    _12 = vec2_i_39 & 1;
> > :
> >
> > so that vectorizer won't failed due to
> >
> >   /* If this isn't a nested cycle or if the nested cycle reduction value
> >      is used ouside of the inner loop we cannot handle uses of the reduction
> >      value.  */
> >   if (nlatch_def_loop_uses > 1 || nphi_def_loop_uses > 1)
> >     {
> >       if (dump_enabled_p ())
> >         dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
> >                          "reduction used in loop.\n");
> >       return NULL;
> >     }
> >
> > Bootstrap and regtest on x86_64-pc-linux-gnu{-m32,}
> > Ok for trunk?
> >
> > gcc/ChangeLog:
> >
> >         PR tree-optimization/103126
> >         * tree-if-conv.c (is_cond_scalar_reduction): Handle
> >         BIT_XOR_EXPR/BIT_IOR_EXPR/BIT_AND_EXPR.
> >         (convert_scalar_cond_reduction): Ditto.
> >
> > gcc/testsuite/ChangeLog:
> >
> >         * gcc.target/i386/ifcvt-reduction-logic-op.c: New test.
> > ---
> >  .../i386/ifcvt-reduction-logic-op.c           | 80 +++++++++++++++++++
> >  gcc/tree-if-conv.c                            | 19 +++--
> >  2 files changed, 92 insertions(+), 7 deletions(-)
> >  create mode 100644 gcc/testsuite/gcc.target/i386/ifcvt-reduction-logic-op.c
> >
> > diff --git a/gcc/testsuite/gcc.target/i386/ifcvt-reduction-logic-op.c b/gcc/testsuite/gcc.target/i386/ifcvt-reduction-logic-op.c
> > new file mode 100644
> > index 00000000000..eeb822d5d43
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/ifcvt-reduction-logic-op.c
> > @@ -0,0 +1,80 @@
> > +/* PR tree-optimization/103126.  */
> > +/* { dg-do compile } */
> > +/* { dg-options "-Ofast -mavx2 -ftree-vectorize -fdump-tree-vect-details" } */
> > +/* { dg-final { scan-tree-dump-times "vectorized \[1-3] loops" 3 "vect" } } */
> > +#include<stdint.h>
> > +
> > +void xor_bit_arr_nolcd (uint64_t *__restrict mat, uint64_t* a,uint64_t* b, uint64_t *__restrict ans,
> > +    int64_t n)
> > +{
> > +  int64_t i;
> > +  uint64_t vec1, sum1;
> > +  uint64_t vec2, sum2;
> > +
> > +  while (n > 0) {
> > +    sum1 = 0;
> > +    vec1 = a[n];
> > +    sum2 = 0;
> > +    vec2 = b[n];
> > +
> > +    for (i = 0; i < 64; i++) {
> > +      uint64_t tmp = mat[i];
> > +      uint64_t vec1_i = (vec1 >> i);
> > +      uint64_t vec2_i = (vec2 >> i);
> > +      sum1 ^= (vec1_i & 1) ? tmp : 0;
> > +      if (vec2_i&1) sum2 ^= tmp;
> > +    }
> > +    *ans++ ^= sum1;  n--;
> > +    *ans++ ^= sum2;  n--;
> > +  }
> > +}
> > +
> > +void ior_bit_arr_nolcd (uint64_t *__restrict mat, uint64_t* a,uint64_t* b, uint64_t *__restrict ans,
> > +    int64_t n)
> > +{
> > +  int64_t i;
> > +  uint64_t vec1, sum1;
> > +  uint64_t vec2, sum2;
> > +
> > +  while (n > 0) {
> > +    sum1 = 0;
> > +    vec1 = a[n];
> > +    sum2 = 0;
> > +    vec2 = b[n];
> > +
> > +    for (i = 0; i < 64; i++) {
> > +      uint64_t tmp = mat[i];
> > +      uint64_t vec1_i = (vec1 >> i);
> > +      uint64_t vec2_i = (vec2 >> i);
> > +      sum1 |= (vec1_i & 1) ? tmp : 0;
> > +      if (vec2_i&1) sum2 |= tmp;
> > +    }
> > +    *ans++ |= sum1;  n--;
> > +    *ans++ |= sum2;  n--;
> > +  }
> > +}
> > +
> > +void and_bit_arr_nolcd (uint64_t *__restrict mat, uint64_t* a,uint64_t* b, uint64_t *__restrict ans,
> > +    int64_t n)
> > +{
> > +  int64_t i;
> > +  uint64_t vec1, sum1;
> > +  uint64_t vec2, sum2;
> > +
> > +  while (n > 0) {
> > +    sum1 = -1;
> > +    vec1 = a[n];
> > +    sum2 = 0;
> > +    vec2 = b[n];
> > +
> > +    for (i = 0; i < 64; i++) {
> > +      uint64_t tmp = mat[i];
> > +      uint64_t vec1_i = (vec1 >> i);
> > +      uint64_t vec2_i = (vec2 >> i);
> > +      sum1 &= (vec1_i & 1) ? tmp : -1;
> > +      if (vec2_i&1) sum2 &= tmp;
> > +    }
> > +    *ans++ &= sum1;  n--;
> > +    *ans++ &= sum2;  n--;
> > +  }
> > +}
> > diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c
> > index b165dc0c17f..7df1103ff89 100644
> > --- a/gcc/tree-if-conv.c
> > +++ b/gcc/tree-if-conv.c
> > @@ -1732,7 +1732,9 @@ is_cond_scalar_reduction (gimple *phi, gimple **reduc, tree arg_0, tree arg_1,
> >        reduction_op = gimple_assign_rhs_code (stmt);
> >      }
> >
> > -  if (reduction_op != PLUS_EXPR && reduction_op != MINUS_EXPR)
> > +  if (reduction_op != PLUS_EXPR && reduction_op != MINUS_EXPR
> > +     && reduction_op != BIT_IOR_EXPR && reduction_op != BIT_XOR_EXPR
> > +     && reduction_op != BIT_AND_EXPR)
>
> Please put each && on a separate line
Changed.
>
> >      return false;
> >    r_op1 = gimple_assign_rhs1 (stmt);
> >    r_op2 = gimple_assign_rhs2 (stmt);
> > @@ -1742,7 +1744,7 @@ is_cond_scalar_reduction (gimple *phi, gimple **reduc, tree arg_0, tree arg_1,
> >
> >    /* Make R_OP1 to hold reduction variable.  */
> >    if (r_nop2 == PHI_RESULT (header_phi)
> > -      && reduction_op == PLUS_EXPR)
> > +      && commutative_tree_code (reduction_op))
> >      {
> >        std::swap (r_op1, r_op2);
> >        std::swap (r_nop1, r_nop2);
> > @@ -1811,7 +1813,10 @@ convert_scalar_cond_reduction (gimple *reduc, gimple_stmt_iterator *gsi,
> >    tree rhs1 = gimple_assign_rhs1 (reduc);
> >    tree tmp = make_temp_ssa_name (TREE_TYPE (rhs1), NULL, "_ifc_");
> >    tree c;
> > -  tree zero = build_zero_cst (TREE_TYPE (rhs1));
> > +  enum tree_code reduction_op  = gimple_assign_rhs_code (reduc);
> > +  tree op_nochange = reduction_op != BIT_AND_EXPR
> > +    ? build_zero_cst (TREE_TYPE (rhs1))
> > +    : build_minus_one_cst (TREE_TYPE (rhs1));
>
> maybe export neutral_op_for_reduction and use it here (supply NULL
> initial_value)?
Changed(didn't know there's such function.)
>
> Otherwise looks OK.
>
> Thanks,
> Richard.
>
> >    gimple_seq stmts = NULL;
> >
> >    if (dump_file && (dump_flags & TDF_DETAILS))
> > @@ -1824,14 +1829,14 @@ convert_scalar_cond_reduction (gimple *reduc, gimple_stmt_iterator *gsi,
> >       of reduction rhs.  */
> >    c = fold_build_cond_expr (TREE_TYPE (rhs1),
> >                             unshare_expr (cond),
> > -                           swap ? zero : op1,
> > -                           swap ? op1 : zero);
> > +                           swap ? op_nochange : op1,
> > +                           swap ? op1 : op_nochange);
> >
> >    /* Create assignment stmt and insert it at GSI.  */
> >    new_assign = gimple_build_assign (tmp, c);
> >    gsi_insert_before (gsi, new_assign, GSI_SAME_STMT);
> > -  /* Build rhs for unconditional increment/decrement.  */
> > -  rhs = gimple_build (&stmts, gimple_assign_rhs_code (reduc),
> > +  /* Build rhs for unconditional increment/decrement/logic_operation.  */
> > +  rhs = gimple_build (&stmts, reduction_op,
> >                       TREE_TYPE (rhs1), op0, tmp);
> >
> >    if (has_nop)
> > --
> > 2.18.1
> >


Here's the patch i'm going to check in.
-- 
BR,
Hongtao
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