tree-optimization/104595 - vectorization of COND_EXPR with bool load

  The following fixes an omission in bool pattern detection that
makes it fail when check_bool_pattern fails for COND_EXPR.  That's
not what it should do, instead it should still pattern recog
to var != 0 even if no further adjustments to the def chain are
necessary when var is not a mask already.

Bootstrapped and tested on x86_64-unknown-linux-gnu, queued for stage1.

There's another piece of the PR not yet fixed.

2022-02-21  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/104595
	* tree-vect-patterns.c (vect_recog_bool_pattern): For
	COND_EXPR do not fail if check_bool_pattern returns false.

	* gcc.dg/vect/pr104595.c: New testcase.
---
 gcc/testsuite/gcc.dg/vect/pr104595.c | 24 ++++++++++++++++++++++++
 gcc/tree-vect-patterns.cc            | 16 ++++++++--------
 2 files changed, 32 insertions(+), 8 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/vect/pr104595.c
  

On Mon, Feb 21, 2022 at 4:54 PM Richard Biener via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> The following fixes an omission in bool pattern detection that
> makes it fail when check_bool_pattern fails for COND_EXPR.  That's
> not what it should do, instead it should still pattern recog
> to var != 0 even if no further adjustments to the def chain are
> necessary when var is not a mask already.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu, queued for stage1.
>
> There's another piece of the PR not yet fixed.

Re-tested on x86_64-unknown-linux-gnu, about to push if gcc.gnu.org lets me.

Richard.

> 2022-02-21  Richard Biener  <rguenther@suse.de>
>
>         PR tree-optimization/104595
>         * tree-vect-patterns.c (vect_recog_bool_pattern): For
>         COND_EXPR do not fail if check_bool_pattern returns false.
>
>         * gcc.dg/vect/pr104595.c: New testcase.
> ---
>  gcc/testsuite/gcc.dg/vect/pr104595.c | 24 ++++++++++++++++++++++++
>  gcc/tree-vect-patterns.cc            | 16 ++++++++--------
>  2 files changed, 32 insertions(+), 8 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.dg/vect/pr104595.c
>
> diff --git a/gcc/testsuite/gcc.dg/vect/pr104595.c b/gcc/testsuite/gcc.dg/vect/pr104595.c
> new file mode 100644
> index 00000000000..bb7d79aa69f
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/vect/pr104595.c
> @@ -0,0 +1,24 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target vect_condition } */
> +
> +#define N 256
> +typedef char T;
> +extern T a[N];
> +extern T b[N];
> +extern T c[N];
> +extern _Bool pb[N];
> +extern char pc[N];
> +
> +void predicate_by_bool()
> +{
> +  for (int i = 0; i < N; i++)
> +    c[i] = pb[i] ? a[i] : b[i];
> +}
> +
> +void predicate_by_char()
> +{
> +  for (int i = 0; i < N; i++)
> +    c[i] = pc[i] ? a[i] : b[i];
> +}
> +
> +/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 2 "vect" } } */
> diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
> index 217bdfd7045..8c61eb965a6 100644
> --- a/gcc/tree-vect-patterns.cc
> +++ b/gcc/tree-vect-patterns.cc
> @@ -4450,18 +4450,18 @@ vect_recog_bool_pattern (vec_info *vinfo,
>        if (get_vectype_for_scalar_type (vinfo, type) == NULL_TREE)
>         return NULL;
>
> -      if (!check_bool_pattern (var, vinfo, bool_stmts))
> +      if (check_bool_pattern (var, vinfo, bool_stmts))
> +       var = adjust_bool_stmts (vinfo, bool_stmts, type, stmt_vinfo);
> +      else if (integer_type_for_mask (var, vinfo))
>         return NULL;
>
> -      rhs = adjust_bool_stmts (vinfo, bool_stmts, type, stmt_vinfo);
> -
>        lhs = vect_recog_temp_ssa_var (TREE_TYPE (lhs), NULL);
>        pattern_stmt
> -         = gimple_build_assign (lhs, COND_EXPR,
> -                                build2 (NE_EXPR, boolean_type_node,
> -                                        rhs, build_int_cst (type, 0)),
> -                                gimple_assign_rhs2 (last_stmt),
> -                                gimple_assign_rhs3 (last_stmt));
> +       = gimple_build_assign (lhs, COND_EXPR,
> +                              build2 (NE_EXPR, boolean_type_node,
> +                                      var, build_int_cst (TREE_TYPE (var), 0)),
> +                              gimple_assign_rhs2 (last_stmt),
> +                              gimple_assign_rhs3 (last_stmt));
>        *type_out = vectype;
>        vect_pattern_detected ("vect_recog_bool_pattern", last_stmt);
>
> --
> 2.34.1