On Thu, Jun 16, 2011 at 10:00 AM, Richard Guenther
<richard.guent...@gmail.com> wrote:
> On Thu, Jun 16, 2011 at 8:54 AM, Ira Rosen <ira.ro...@linaro.org> wrote:
>> Hi,
>>
>> For
>>
>> unsigned char in[N];
>> int out[N];
>> for (i = 0; i < N; i++)
>> out[i] = in[i] * 300;
>>
>> in[i] is first promoted to int and then multiplied by 300. This
>> over-promotion prevents the vectorizer from using the widen-mult
>> pattern here.
>>
>> This patch checks if a constant fits an intermediate type (short in
>> this example) and generates widen-mult operation on that type. I.e.,
>> the following sequence:
>>
>> type a_t;
>> TYPE a_T, prod_T;
>>
>> S1 a_t = ;
>> S3 a_T = (TYPE) a_t;
>> S5 prod_T = a_T * CONST;
>>
>> is marked as:
>>
>> type a_t;
>> interm_type a_it;
>> TYPE a_T, prod_T, prod_T';
>>
>> S1 a_t = ;
>> S3 a_T = (TYPE) a_t;
>> '--> a_it = (interm_type) a_t;
>> S5 prod_T = a_T * CONST;
>> '--> prod_T' = a_it w* CONST;
>>
>>
>> by the pattern detection (and later vectorized using the new statements).
>>
>> Bootstrapped and tested on powerpc64-suse-linux.
>> Comments are welcome.
>
> + && TREE_CODE (half_type1) == INTEGER_TYPE)
> + {
> + if (int_fits_type_p (oprnd0, half_type1))
>
> I believe you need to check that oprnd0 is a INTEGER_CST before calling
> int_fits_type_p.
>
> + {
> + /* OPRND0 is a constant of HALF_TYPE1. */
>
> The whole following block is repeated twice, nearly identical - that asks
> for factoring it out.
>
> Otherwise the patch looks reasonable.
Oh ...
+ /* TYPE is 4 times bigger than HALF_TYPE1, try widen-mult for
+ a type 2 times bigger than HALF_TYPE1. */
+ new_type = lang_hooks.types.type_for_size (
+ TYPE_PRECISION (type) / 2,
+ TYPE_UNSIGNED (type));
don't use lang-hooks but instead use build_nonstandard_integer_type here.
Richard.
> Thanks,
> Richard.
>
>> Thanks,
>> Ira
>>
>>
>> ChangeLog:
>>
>> * tree-vectorizer.h (vect_recog_func_ptr): Change the first
>> argument to be a VEC of statements.
>> * tree-vect-loop.c (vect_determine_vectorization_factor):
>> Remove the assert that pattern statements have to have their
>> vector type set.
>> * tree-vect-patterns.c (langhooks.h): Include.
>> (vect_recog_widen_sum_pattern): Change the first argument
>> to be a VEC of statements. Update documentation.
>> (vect_recog_dot_prod_pattern, vect_recog_pow_pattern):
>> Likewise.
>> (vect_recog_widen_mult_pattern): Likewise and support
>> multiplication by a constant that fits an intermediate type.
>> Use int_fits_type_p instead of comparing to types max and
>> min values.
>> (vect_pattern_recog_1): Update vect_recog_func_ptr and its
>> call. Handle additional pattern statements if necessary.
>> * Makefile.in (tree-vect-patterns.c): Add dependency on
>> langhooks.h.
>>
>> testsuite/ChangeLog:
>>
>> * gcc.dg/vect/vect-widen-mult-half-u8.c: New test.
>>
>
