On Wed, Jun 1, 2011 at 11:23 AM, Ira Rosen <ira.ro...@linaro.org> wrote: > Hi, > > The vectorizer expects widening multiplication pattern to be: > > type a_t, b_t; > TYPE a_T, b_T, prod_T; > > a_T = (TYPE) a_t; > b_T = (TYPE) b_t; > prod_T = a_T * b_T; > > where type 'TYPE' is double the size of type 'type'. This works fine > when the types are signed. For the unsigned types the code looks like: > > unsigned type a_t, b_t; > unsigned TYPE u_prod_T; > TYPE a_T, b_T, prod_T; > > a_T = (TYPE) a_t; > b_T = (TYPE) b_t; > prod_T = a_T * b_T; > u_prod_T = (unsigned TYPE) prod_T; > > i.e., the multiplication is done on signed, followed by a cast to unsigned. > This patch adds a support of such patterns and generates > WIDEN_MULT_EXPR for the unsigned type. > > Another unsupported case is multiplication by a constant (e.g., b_T is > a constant). This patch checks that the constant fits the smaller type > 'type' and recognizes such cases as widening multiplication. > > Bootstrapped and tested on powerpc64-suse-linux. Tested the > vectorization testsuite on arm-linux-gnueabi. > I'll commit the patch shortly if there are no comments/objections.
Did you think about moving pass_optimize_widening_mul before loop optimizations? Does that pass catch the cases you are teaching the pattern recognizer? I think we should try to expose these more complicated instructions to loop optimizers. Thanks, Richard. > Ira > > ChangeLog: > > * tree-vectorizer.h (vect_recog_func_ptr): Make last argument to be > a pointer. > * tree-vect-patterns.c (vect_recog_widen_sum_pattern, > vect_recog_widen_mult_pattern, vect_recog_dot_prod_pattern, > vect_recog_pow_pattern): Likewise. > (vect_pattern_recog_1): Remove declaration. > (widened_name_p): Remove declaration. Add new argument to specify > whether to check that both types are either signed or unsigned. > (vect_recog_widen_mult_pattern): Update documentation. Handle > unsigned patterns and multiplication by constants. > (vect_pattern_recog_1): Update vect_recog_func references. Use > statement information from the statement returned from pattern > detection functions. > (vect_pattern_recog): Update vect_recog_func reference. > * tree-vect-stmts.c (vectorizable_type_promotion): For widening > multiplication by a constant use the type of the other operand. > > testsuite/ChangeLog: > > * lib/target-supports.exp > (check_effective_target_vect_widen_mult_qi_to_hi): > Add NEON as supporting target. > (check_effective_target_vect_widen_mult_hi_to_si): Likewise. > (check_effective_target_vect_widen_mult_qi_to_hi_pattern): New. > (check_effective_target_vect_widen_mult_hi_to_si_pattern): New. > * gcc.dg/vect/vect-widen-mult-u8.c: Expect to be vectorized > using widening > multiplication on targets that support it. > * gcc.dg/vect/vect-widen-mult-u16.c: Likewise. > * gcc.dg/vect/vect-widen-mult-const-s16.c: New test. > * gcc.dg/vect/vect-widen-mult-const-u16.c: New test. >
