Add a vect_get_num_copies helper routine

[Richard Sandiford]

"H.J. Lu" <hjl.tools@gmail.com> writes:
> 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

Yeah, it did, sorry.  I've just committed a fix.

Thanks,
Richard