On Thu, May 24, 2018 at 2:52 PM Richard Sandiford <
richard.sandif...@linaro.org> wrote:
> Richard Biener <richard.guent...@gmail.com> writes:
> > On Thu, May 24, 2018 at 10:31 AM Jakub Jelinek <ja...@redhat.com> wrote:
> >> On Thu, May 24, 2018 at 09:21:35AM +0100, Richard Sandiford wrote:
> >> > vect_recog_divmod_pattern currently bails out if the target has
> >> > native support for integer division, but I think in practice
> >> > it's always going to be better to open-code it anyway, just as
> >> > we usually open-code scalar divisions by constants.
> >> >
> >> > I think the only currently affected target is MIPS MSA, where for:
> >
> >> Isn't powerpcspe affected too? It has a divv2si3 pattern.
> Ah, yeah. I forgot to update the description after you mentioned
> that on IRC, sorry.
> >> > --- gcc/tree-vect-patterns.c 2018-05-16 12:48:59.115202362 +0100
> >> > +++ gcc/tree-vect-patterns.c 2018-05-24 09:18:10.445466941 +0100
> >> > @@ -2639,7 +2639,6 @@ vect_recog_divmod_pattern (vec<gimple *>
> >> > enum tree_code rhs_code;
> >> > stmt_vec_info stmt_vinfo = vinfo_for_stmt (last_stmt);
> >> > vec_info *vinfo = stmt_vinfo->vinfo;
> >> > - optab optab;
> >> > tree q;
> >> > int dummy_int, prec;
> >> > stmt_vec_info def_stmt_vinfo;
> >> > @@ -2674,17 +2673,6 @@ vect_recog_divmod_pattern (vec<gimple *>
> >> > if (vectype == NULL_TREE)
> >> > return NULL;
> >> >
> >> > - /* If the target can handle vectorized division or modulo
natively,
> >> > - don't attempt to optimize this. */
> >> > - optab = optab_for_tree_code (rhs_code, vectype, optab_default);
> >> > - if (optab != unknown_optab)
> >> > - {
> >> > - machine_mode vec_mode = TYPE_MODE (vectype);
> >> > - int icode = (int) optab_handler (optab, vec_mode);
> >> > - if (icode != CODE_FOR_nothing)
> >> > - return NULL;
> >> > - }
> >> > -
> >
> >> Shouldn't we instead keep it, but only do it if
> >> optimize_bb_for_size_p (gimple_bb (last_stmt)) ?
> >> I mean, a hw division is very likely shorter than what we replace it
> > with...
> >
> > Good idea. While loops are checked for optimize_loop_nest_for_speed if
> > not forced vect BB vectorization has no such predicate.
> Like this, if it passes testing?
Looks good.
Thanks,
Richard.
> Thanks,
> Richard
> 2018-05-24 Richard Sandiford <richard.sandif...@linaro.org>
> gcc/
> * tree-vect-patterns.c: Include predict.h.
> (vect_recog_divmod_pattern): Restrict check for division support
> to when optimizing for size.
> gcc/testsuite/
> * gcc.dg/vect/bb-slp-div-1.c: New XFAILed test.
> Index: gcc/tree-vect-patterns.c
> ===================================================================
> *** gcc/tree-vect-patterns.c 2018-05-24 13:50:21.656138942 +0100
> --- gcc/tree-vect-patterns.c 2018-05-24 13:50:21.819134113 +0100
> *************** vect_recog_divmod_pattern (vec<gimple *>
> *** 2674,2688 ****
> if (vectype == NULL_TREE)
> return NULL;
> ! /* If the target can handle vectorized division or modulo natively,
> ! don't attempt to optimize this. */
> ! optab = optab_for_tree_code (rhs_code, vectype, optab_default);
> ! if (optab != unknown_optab)
> {
> ! machine_mode vec_mode = TYPE_MODE (vectype);
> ! int icode = (int) optab_handler (optab, vec_mode);
> ! if (icode != CODE_FOR_nothing)
> ! return NULL;
> }
> prec = TYPE_PRECISION (itype);
> --- 2674,2692 ----
> if (vectype == NULL_TREE)
> return NULL;
> ! if (optimize_bb_for_size_p (gimple_bb (last_stmt)))
> {
> ! /* If the target can handle vectorized division or modulo
natively,
> ! don't attempt to optimize this, since native division is likely
> ! to give smaller code. */
> ! optab = optab_for_tree_code (rhs_code, vectype, optab_default);
> ! if (optab != unknown_optab)
> ! {
> ! machine_mode vec_mode = TYPE_MODE (vectype);
> ! int icode = (int) optab_handler (optab, vec_mode);
> ! if (icode != CODE_FOR_nothing)
> ! return NULL;
> ! }
> }
> prec = TYPE_PRECISION (itype);
> Index: gcc/testsuite/gcc.dg/vect/bb-slp-div-1.c
> ===================================================================
> *** /dev/null 2018-04-20 16:19:46.369131350 +0100
> --- gcc/testsuite/gcc.dg/vect/bb-slp-div-1.c 2018-05-24
13:50:21.818134143 +0100
> ***************
> *** 0 ****
> --- 1,19 ----
> + /* { dg-do compile } */
> + /* { dg-additional-options "-msve-vector-bits=256" { target aarch64_sve
} } */
> +
> + int x[8];
> +
> + void
> + f (void)
> + {
> + x[0] /= 2;
> + x[1] /= 3;
> + x[2] /= 4;
> + x[3] /= 5;
> + x[4] /= 6;
> + x[5] /= 7;
> + x[6] /= 8;
> + x[7] /= 9;
> + }
> +
> + /* { dg-final { scan-tree-dump "basic block vectorized" "slp2" { xfail
*-*-* } } } */
