On Fri, 2012-02-10 at 07:31 -0600, William J. Schmidt wrote:
> Richard, thanks. I can answer most of your questions, but for the last
> one I will have to ask Ira to weigh in.
>
> On Fri, 2012-02-10 at 13:06 +0100, Richard Guenther wrote:
> > On Thu, Feb 9, 2012 at 5:56 PM, William J. Schmidt
> > <wschm...@linux.vnet.ibm.com> wrote:
> > > Following is a revision of yesterday's PR50031 patch submission,
> > > modified per Richard's comments. Bootstrapped and tested with no
> > > regressions on powerpc64-linux. I've confirmed the same performance
> > > improvements in SPEC. OK for trunk?
> >
> > Some more questions - maybe Jakub can clarify as well given he worked
> > on patterns recently ...
> >
> > > Thanks,
> > > Bill
> > >
> > >
> > > 2012-02-09 Bill Schmidt <wschm...@linux.vnet.ibm.com>
> > > Ira Rosen <i...@il.ibm.com>
> > >
> > > PR tree-optimization/50031
> > > * targhooks.c (default_builtin_vectorization_cost): Handle
> > > vec_promote_demote.
> > > * target.h (enum vect_cost_for_stmt): Add vec_promote_demote.
> > > * tree-vect-loop.c (vect_get_single_scalar_iteraion_cost): Handle
> > > all types of reduction and pattern statements.
> > > (vect_estimate_min_profitable_iters): Likewise.
> > > * tree-vect-stmts.c (vect_model_promotion_demotion_cost): New
> > > function.
> > > (vect_get_load_cost): Use vec_perm for permutations; add dump logic
> > > for explicit realigns.
> > > (vectorizable_conversion): Call vect_model_promotion_demotion_cost.
> > > * config/spu/spu.c (spu_builtin_vectorization_cost): Handle
> > > vec_promote_demote.
> > > * config/i386/i386.c (ix86_builtin_vectorization_cost): Likewise.
> > > * config/rs6000/rs6000.c (rs6000_builtin_vectorization_cost):
> > > Update
> > > vec_perm for VSX and handle vec_promote_demote.
> > >
> > >
> > > Index: gcc/targhooks.c
> > > ===================================================================
> > > --- gcc/targhooks.c (revision 183944)
> > > +++ gcc/targhooks.c (working copy)
> > > @@ -514,6 +514,7 @@ default_builtin_vectorization_cost (enum vect_cost
> > > case scalar_to_vec:
> > > case cond_branch_not_taken:
> > > case vec_perm:
> > > + case vec_promote_demote:
> > > return 1;
> > >
> > > case unaligned_load:
> > > Index: gcc/target.h
> > > ===================================================================
> > > --- gcc/target.h (revision 183944)
> > > +++ gcc/target.h (working copy)
> > > @@ -145,7 +145,8 @@ enum vect_cost_for_stmt
> > > scalar_to_vec,
> > > cond_branch_not_taken,
> > > cond_branch_taken,
> > > - vec_perm
> > > + vec_perm,
> > > + vec_promote_demote
> > > };
> > >
> > > /* The target structure. This holds all the backend hooks. */
> > > Index: gcc/tree-vect-loop.c
> > > ===================================================================
> > > --- gcc/tree-vect-loop.c (revision 183944)
> > > +++ gcc/tree-vect-loop.c (working copy)
> > > @@ -2417,7 +2417,8 @@ vect_get_single_scalar_iteraion_cost (loop_vec_inf
> > > if (stmt_info
> > > && !STMT_VINFO_RELEVANT_P (stmt_info)
> > > && (!STMT_VINFO_LIVE_P (stmt_info)
> > > - || STMT_VINFO_DEF_TYPE (stmt_info) !=
> > > vect_reduction_def))
> > > + || !VECTORIZABLE_CYCLE_DEF (STMT_VINFO_DEF_TYPE
> > > (stmt_info)))
> > > + && !STMT_VINFO_IN_PATTERN_P (stmt_info))
> > > continue;
> >
> > Why would we exclude !relevant stmts when they are part of a pattern?
> > We are looking at a scalar iteration cost, so all stmts that are not "dead"
> > count, no?
>
> As I understand it, we're at a point where a statement replacing the
> pattern exists but has not yet been inserted in the code stream. All of
> the statements in the pattern are marked irrelevant, but the related
> statement of the main (last) statement of the pattern is relevant. Thus
> we need to allow the main statement through this check so the
> replacement statement can be found and counted.
>
> >
> > >
> > > if (STMT_VINFO_DATA_REF (vinfo_for_stmt (stmt)))
> > > @@ -2564,15 +2565,48 @@ vect_estimate_min_profitable_iters (loop_vec_info
> > > {
> > > gimple stmt = gsi_stmt (si);
> > > stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
> > > +
> > > + /* Translate the last statement in a pattern into the
> > > + related replacement statement. */
> > > + if (STMT_VINFO_IN_PATTERN_P (stmt_info))
> > > + {
> > > + stmt = STMT_VINFO_RELATED_STMT (stmt_info);
> > > + stmt_info = vinfo_for_stmt (stmt);
> > > + }
> >
> > So here we are tanslating stmt to the "main" scalar pattern stmt - and thus
> > count it as many times as we have stmts in that pattern? That looks wrong.
> > More like
> >
> > if (STMT_VINFO_IN_PATTERN_P (stmt_info)
> > && STMT_VINFO_RELATED_STMT (stmt_info) != stmt)
> > continue;
> >
> > ? Does the main stmt has the flag set and points to itself?
>
> From the commentary at the end of tree-vect-patterns.c, only the main
> statement in the pattern (the last one) is flagged as
> STMT_VINFO_IN_PATTERN_P. So this is finding the new replacement
> statement which has been created but not yet inserted in the code. It
> only gets counted once.
>
> >
> > > /* Skip stmts that are not vectorized inside the loop. */
> > > if (!STMT_VINFO_RELEVANT_P (stmt_info)
> > > && (!STMT_VINFO_LIVE_P (stmt_info)
> > > - || STMT_VINFO_DEF_TYPE (stmt_info) !=
> > > vect_reduction_def))
> > > + || !VECTORIZABLE_CYCLE_DEF (STMT_VINFO_DEF_TYPE
> > > (stmt_info))))
> > > continue;
> > > +
> >
> > ... and then, what does STMT_VINFO_INSIDE_OF_LOOP_COST of
> > that "main" pattern stmt represent? Shouldn't it represent the cost
> > of the whole sequence, and thus ...
> >
> > > vec_inside_cost += STMT_VINFO_INSIDE_OF_LOOP_COST (stmt_info) *
> > > factor;
> > > /* FIXME: for stmts in the inner-loop in outer-loop
> > > vectorization,
> > > some of the "outside" costs are generated inside the
> > > outer-loop. */
> > > vec_outside_cost += STMT_VINFO_OUTSIDE_OF_LOOP_COST (stmt_info);
> > > + if (is_pattern_stmt_p (stmt_info)
> > > + && STMT_VINFO_PATTERN_DEF_SEQ (stmt_info))
> > > + {
> > > + gimple_stmt_iterator gsi;
> >
> > The following is excessive? Especially as you probably count the "main"
> > stmt twice? Thus, if the main stmt cost does not cover the sequence
> > then you should skip adding its cost above?
>
> This is what I believe is going on here. Note that for the main pattern
> statement, we have converted it so that stmt_info now points to its
> related (replacement) statement. It is apparently possible for this
> replacement statement to also be recognized as part of a new pattern
> (I've seen references to such possibilities elsewhere in the vectorizer
> code). When that happens, this code is counting the costs of that
> pattern.
>
> Ira, can you please weigh in on this part? I'm not 100% certain of my
> explanation.
Also, I forgot to mention that I think Richard is right that the
replacement statement may be getting counted twice in this scenario.
>
> In any case, it's clear we need more comments in the code. :)
>
> Note that STMT_VINFO_PATTERN_DEF_SEQ doesn't exist in the 4.6 branch, so
> this section has to be omitted if we backport it (which is desirable
> since the degradation was introduced in 4.6). Removing it apparently
> does not affect the sphinx3 degradation.
>
> >
> > Thanks,
> > Richard.
> >
> > > + for (gsi = gsi_start (STMT_VINFO_PATTERN_DEF_SEQ
> > > (stmt_info));
> > > + !gsi_end_p (gsi); gsi_next (&gsi))
> > > + {
> > > + gimple pattern_def_stmt = gsi_stmt (gsi);
> > > + stmt_vec_info pattern_def_stmt_info
> > > + = vinfo_for_stmt (pattern_def_stmt);
> > > + if (STMT_VINFO_RELEVANT_P (pattern_def_stmt_info)
> > > + || STMT_VINFO_LIVE_P (pattern_def_stmt_info))
> > > + {
> > > + vec_inside_cost
> > > + += STMT_VINFO_INSIDE_OF_LOOP_COST
> > > + (pattern_def_stmt_info) * factor;
> > > + vec_outside_cost
> > > + += STMT_VINFO_OUTSIDE_OF_LOOP_COST
> > > + (pattern_def_stmt_info);
> > > + }
> > > + }
> > > + }
> > > }
> > > }
> > >
> > > Index: gcc/tree-vect-stmts.c
> > > ===================================================================
> > > --- gcc/tree-vect-stmts.c (revision 183944)
> > > +++ gcc/tree-vect-stmts.c (working copy)
> > > @@ -811,6 +811,46 @@ vect_model_simple_cost (stmt_vec_info stmt_info, i
> > > }
> > >
> > >
> > > +/* Model cost for type demotion and promotion operations. PWR is
> > > normally
> > > + zero for single-step promotions and demotions. It will be one if
> > > + two-step promotion/demotion is required, and so on. Each additional
> > > + step doubles the number of instructions required. */
> > > +
> > > +static void
> > > +vect_model_promotion_demotion_cost (stmt_vec_info stmt_info,
> > > + enum vect_def_type *dt, int pwr)
> > > +{
> > > + int i, tmp;
> > > + int inside_cost = 0, outside_cost = 0, single_stmt_cost;
> > > +
> > > + /* The SLP costs were already calculated during SLP tree build. */
> > > + if (PURE_SLP_STMT (stmt_info))
> > > + return;
> > > +
> > > + single_stmt_cost = vect_get_stmt_cost (vec_promote_demote);
> > > + for (i = 0; i < pwr + 1; i++)
> > > + {
> > > + tmp = (STMT_VINFO_TYPE (stmt_info) ==
> > > type_promotion_vec_info_type) ?
> > > + (i + 1) : i;
> > > + inside_cost += vect_pow2 (tmp) * single_stmt_cost;
> > > + }
> > > +
> > > + /* FORNOW: Assuming maximum 2 args per stmts. */
> > > + for (i = 0; i < 2; i++)
> > > + {
> > > + if (dt[i] == vect_constant_def || dt[i] == vect_external_def)
> > > + outside_cost += vect_get_stmt_cost (vector_stmt);
> > > + }
> > > +
> > > + if (vect_print_dump_info (REPORT_COST))
> > > + fprintf (vect_dump, "vect_model_promotion_demotion_cost: inside_cost
> > > = %d, "
> > > + "outside_cost = %d .", inside_cost, outside_cost);
> > > +
> > > + /* Set the costs in STMT_INFO. */
> > > + stmt_vinfo_set_inside_of_loop_cost (stmt_info, NULL, inside_cost);
> > > + stmt_vinfo_set_outside_of_loop_cost (stmt_info, NULL, outside_cost);
> > > +}
> > > +
> > > /* Function vect_cost_strided_group_size
> > >
> > > For strided load or store, return the group_size only if it is the
> > > first
> > > @@ -887,7 +927,6 @@ vect_model_store_cost (stmt_vec_info stmt_info, in
> > > if (vect_print_dump_info (REPORT_COST))
> > > fprintf (vect_dump, "vect_model_store_cost: strided group_size =
> > > %d .",
> > > group_size);
> > > -
> > > }
> > >
> > > /* Costs of the stores. */
> > > @@ -1049,7 +1088,7 @@ vect_get_load_cost (struct data_reference *dr, int
> > > case dr_explicit_realign:
> > > {
> > > *inside_cost += ncopies * (2 * vect_get_stmt_cost (vector_load)
> > > - + vect_get_stmt_cost (vector_stmt));
> > > + + vect_get_stmt_cost (vec_perm));
> > >
> > > /* FIXME: If the misalignment remains fixed across the iterations
> > > of
> > > the containing loop, the following cost should be added to the
> > > @@ -1057,6 +1096,9 @@ vect_get_load_cost (struct data_reference *dr, int
> > > if (targetm.vectorize.builtin_mask_for_load)
> > > *inside_cost += vect_get_stmt_cost (vector_stmt);
> > >
> > > + if (vect_print_dump_info (REPORT_COST))
> > > + fprintf (vect_dump, "vect_model_load_cost: explicit realign");
> > > +
> > > break;
> > > }
> > > case dr_explicit_realign_optimized:
> > > @@ -1080,7 +1122,12 @@ vect_get_load_cost (struct data_reference *dr, int
> > > }
> > >
> > > *inside_cost += ncopies * (vect_get_stmt_cost (vector_load)
> > > - + vect_get_stmt_cost (vector_stmt));
> > > + + vect_get_stmt_cost (vec_perm));
> > > +
> > > + if (vect_print_dump_info (REPORT_COST))
> > > + fprintf (vect_dump,
> > > + "vect_model_load_cost: explicit realign optimized");
> > > +
> > > break;
> > > }
> > >
> > > @@ -2392,16 +2439,19 @@ vectorizable_conversion (gimple stmt, gimple_stmt_
> > > if (vect_print_dump_info (REPORT_DETAILS))
> > > fprintf (vect_dump, "=== vectorizable_conversion ===");
> > > if (code == FIX_TRUNC_EXPR || code == FLOAT_EXPR)
> > > - STMT_VINFO_TYPE (stmt_info) = type_conversion_vec_info_type;
> > > + {
> > > + STMT_VINFO_TYPE (stmt_info) = type_conversion_vec_info_type;
> > > + vect_model_simple_cost (stmt_info, ncopies, dt, NULL);
> > > + }
> > > else if (modifier == NARROW)
> > > {
> > > STMT_VINFO_TYPE (stmt_info) = type_demotion_vec_info_type;
> > > - vect_model_simple_cost (stmt_info, ncopies, dt, NULL);
> > > + vect_model_promotion_demotion_cost (stmt_info, dt,
> > > multi_step_cvt);
> > > }
> > > else
> > > {
> > > STMT_VINFO_TYPE (stmt_info) = type_promotion_vec_info_type;
> > > - vect_model_simple_cost (stmt_info, 2 * ncopies, dt, NULL);
> > > + vect_model_promotion_demotion_cost (stmt_info, dt,
> > > multi_step_cvt);
> > > }
> > > VEC_free (tree, heap, interm_types);
> > > return true;
> > > Index: gcc/config/spu/spu.c
> > > ===================================================================
> > > --- gcc/config/spu/spu.c (revision 183944)
> > > +++ gcc/config/spu/spu.c (working copy)
> > > @@ -6920,6 +6920,7 @@ spu_builtin_vectorization_cost (enum vect_cost_for
> > > case scalar_to_vec:
> > > case cond_branch_not_taken:
> > > case vec_perm:
> > > + case vec_promote_demote:
> > > return 1;
> > >
> > > case scalar_store:
> > > Index: gcc/config/i386/i386.c
> > > ===================================================================
> > > --- gcc/config/i386/i386.c (revision 183944)
> > > +++ gcc/config/i386/i386.c (working copy)
> > > @@ -35336,6 +35336,7 @@ ix86_builtin_vectorization_cost (enum vect_cost_fo
> > > return ix86_cost->cond_not_taken_branch_cost;
> > >
> > > case vec_perm:
> > > + case vec_promote_demote:
> > > return ix86_cost->vec_stmt_cost;
> > >
> > > default:
> > > Index: gcc/config/rs6000/rs6000.c
> > > ===================================================================
> > > --- gcc/config/rs6000/rs6000.c (revision 183944)
> > > +++ gcc/config/rs6000/rs6000.c (working copy)
> > > @@ -3543,10 +3543,17 @@ rs6000_builtin_vectorization_cost (enum vect_cost_
> > > return 1;
> > >
> > > case vec_perm:
> > > - if (!TARGET_VSX)
> > > + if (TARGET_VSX)
> > > + return 4;
> > > + else
> > > return 1;
> > > - return 2;
> > >
> > > + case vec_promote_demote:
> > > + if (TARGET_VSX)
> > > + return 5;
> > > + else
> > > + return 1;
> > > +
> > > case cond_branch_taken:
> > > return 3;
> > >
> > >
> > >
> >
