[PR69956] Fix multi-step conversion of boolean vectors

Hi,

Currently multi-step vector conversion tries to compute
intermediate type from its mode but it doesn't work for
boolean vectors.  This patch introduces a computation
of intermediate vector masks.  Bootstrapped and tested
on x86_64-pc-linux-gnu.  OK for trunk?

Thanks,
Ilya
--
gcc/

2016-02-26  Ilya Enkovich  <enkovich.gnu@gmail.com>

	PR tree-optimization/69956
	* tree-vect-stmts.c (supportable_widening_operation): Support
	multi-step conversion of boolean vectors.
	(supportable_narrowing_operation): Likewise.

gcc/testsuite/

2016-02-26  Ilya Enkovich  <enkovich.gnu@gmail.com>

	PR tree-optimization/69956
	* gcc.dg/pr69956.c: New test.

On Fri, Feb 26, 2016 at 10:22 AM, Ilya Enkovich <enkovich.gnu@gmail.com> wrote:
> Hi,
>
> Currently multi-step vector conversion tries to compute
> intermediate type from its mode but it doesn't work for
> boolean vectors.  This patch introduces a computation
> of intermediate vector masks.  Bootstrapped and tested
> on x86_64-pc-linux-gnu.  OK for trunk?

Ok.

Richard.

> Thanks,
> Ilya
> --
> gcc/
>
> 2016-02-26  Ilya Enkovich  <enkovich.gnu@gmail.com>
>
>         PR tree-optimization/69956
>         * tree-vect-stmts.c (supportable_widening_operation): Support
>         multi-step conversion of boolean vectors.
>         (supportable_narrowing_operation): Likewise.
>
> gcc/testsuite/
>
> 2016-02-26  Ilya Enkovich  <enkovich.gnu@gmail.com>
>
>         PR tree-optimization/69956
>         * gcc.dg/pr69956.c: New test.
>
>
> diff --git a/gcc/testsuite/gcc.dg/pr69956.c b/gcc/testsuite/gcc.dg/pr69956.c
> new file mode 100644
> index 0000000..37d24d4
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr69956.c
> @@ -0,0 +1,11 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -ftree-vectorize" } */
> +/* { dg-additional-options "-march=skylake-avx512" { target { i?86-*-* x86_64-*-* } } } */
> +
> +void
> +fn1 (char *b, char *d, int *c, int i)
> +{
> +  for (; i; i++, d++)
> +    if (b[i])
> +      *d = c[i];
> +}
> diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
> index 9678d7c..182b277 100644
> --- a/gcc/tree-vect-stmts.c
> +++ b/gcc/tree-vect-stmts.c
> @@ -9000,9 +9000,19 @@ supportable_widening_operation (enum tree_code code, gimple *stmt,
>    for (i = 0; i < MAX_INTERM_CVT_STEPS; i++)
>      {
>        intermediate_mode = insn_data[icode1].operand[0].mode;
> -      intermediate_type
> -       = lang_hooks.types.type_for_mode (intermediate_mode,
> -                                         TYPE_UNSIGNED (prev_type));
> +      if (VECTOR_BOOLEAN_TYPE_P (prev_type))
> +       {
> +         intermediate_type
> +           = build_truth_vector_type (TYPE_VECTOR_SUBPARTS (prev_type) / 2,
> +                                      current_vector_size);
> +         if (intermediate_mode != TYPE_MODE (intermediate_type))
> +           return false;
> +       }
> +      else
> +       intermediate_type
> +         = lang_hooks.types.type_for_mode (intermediate_mode,
> +                                           TYPE_UNSIGNED (prev_type));
> +
>        optab3 = optab_for_tree_code (c1, intermediate_type, optab_default);
>        optab4 = optab_for_tree_code (c2, intermediate_type, optab_default);
>
> @@ -9065,7 +9075,7 @@ supportable_narrowing_operation (enum tree_code code,
>    tree vectype = vectype_in;
>    tree narrow_vectype = vectype_out;
>    enum tree_code c1;
> -  tree intermediate_type;
> +  tree intermediate_type, prev_type;
>    machine_mode intermediate_mode, prev_mode;
>    int i;
>    bool uns;
> @@ -9111,6 +9121,7 @@ supportable_narrowing_operation (enum tree_code code,
>    /* Check if it's a multi-step conversion that can be done using intermediate
>       types.  */
>    prev_mode = vec_mode;
> +  prev_type = vectype;
>    if (code == FIX_TRUNC_EXPR)
>      uns = TYPE_UNSIGNED (vectype_out);
>    else
> @@ -9145,8 +9156,17 @@ supportable_narrowing_operation (enum tree_code code,
>    for (i = 0; i < MAX_INTERM_CVT_STEPS; i++)
>      {
>        intermediate_mode = insn_data[icode1].operand[0].mode;
> -      intermediate_type
> -       = lang_hooks.types.type_for_mode (intermediate_mode, uns);
> +      if (VECTOR_BOOLEAN_TYPE_P (prev_type))
> +       {
> +         intermediate_type
> +           = build_truth_vector_type (TYPE_VECTOR_SUBPARTS (prev_type) * 2,
> +                                      current_vector_size);
> +         if (intermediate_mode != TYPE_MODE (intermediate_type))
> +             return false;
> +       }
> +      else
> +       intermediate_type
> +         = lang_hooks.types.type_for_mode (intermediate_mode, uns);
>        interm_optab
>         = optab_for_tree_code (VEC_PACK_TRUNC_EXPR, intermediate_type,
>                                optab_default);
> @@ -9164,6 +9184,7 @@ supportable_narrowing_operation (enum tree_code code,
>         return true;
>
>        prev_mode = intermediate_mode;
> +      prev_type = intermediate_type;
>        optab1 = interm_optab;
>      }
>