Add a vect_get_num_copies helper routine

[H.J. Lu]

On Thu, Sep 14, 2017 at 4:22 AM, Richard Sandiford
<richard.sandiford@linaro.org> wrote:
> This patch adds a vectoriser helper routine to calculate how
> many copies of a vector statement we need.  At present this
> is always:
>
>   LOOP_VINFO_VECT_FACTOR (loop_vinfo) / TYPE_VECTOR_SUBPARTS (vectype)
>
> but later patches add other cases.  Another benefit of using
> a helper routine is that it can assert that the division is
> exact (which it must be).
>
> Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu.
> OK to install?
>
> Richard
>
>
> 2017-09-14  Richard Sandiford  <richard.sandiford@linaro.org>
>             Alan Hayward  <alan.hayward@arm.com>
>             David Sherwood  <david.sherwood@arm.com>
>
> gcc/
>         * tree-vectorizer.h (vect_get_num_copies): New function.
>         * tree-vect-data-refs.c (vect_get_data_access_cost): Use it.
>         * tree-vect-loop.c (vectorizable_reduction): Likewise.
>         (vectorizable_induction): Likewise.
>         (vectorizable_live_operation): Likewise.
>         * tree-vect-stmts.c (vectorizable_mask_load_store): Likewise.
>         (vectorizable_bswap): Likewise.
>         (vectorizable_call): Likewise.
>         (vectorizable_conversion): Likewise.
>         (vectorizable_assignment): Likewise.
>         (vectorizable_shift): Likewise.
>         (vectorizable_operation): Likewise.
>         (vectorizable_store): Likewise.
>         (vectorizable_load): Likewise.
>         (vectorizable_condition): Likewise.
>         (vectorizable_comparison): Likewise.
>         (vect_analyze_stmt): Pass the slp node to vectorizable_live_operation.
>
> Index: gcc/tree-vectorizer.h
> ===================================================================
> --- gcc/tree-vectorizer.h       2017-09-14 11:25:32.166167193 +0100
> +++ gcc/tree-vectorizer.h       2017-09-14 11:27:50.352072753 +0100
> @@ -1076,6 +1076,20 @@ unlimited_cost_model (loop_p loop)
>    return (flag_vect_cost_model == VECT_COST_MODEL_UNLIMITED);
>  }
>
> +/* Return the number of copies needed for loop vectorization when
> +   a statement operates on vectors of type VECTYPE.  This is the
> +   vectorization factor divided by the number of elements in
> +   VECTYPE and is always known at compile time.  */
> +
> +static inline unsigned int
> +vect_get_num_copies (loop_vec_info loop_vinfo, tree vectype)
> +{
> +  gcc_checking_assert (LOOP_VINFO_VECT_FACTOR (loop_vinfo)
> +                      % TYPE_VECTOR_SUBPARTS (vectype) == 0);
> +  return (LOOP_VINFO_VECT_FACTOR (loop_vinfo)
> +         / TYPE_VECTOR_SUBPARTS (vectype));
> +}
> +
>  /* Source location */
>  extern source_location vect_location;
>

I believe this caused:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82228

H.J.