2 * Copyright 2012 Ecole Normale Superieure
4 * Use of this software is governed by the MIT license
6 * Written by Sven Verdoolaege,
7 * Ecole Normale Superieure, 45 rue d’Ulm, 75230 Paris, France
14 #include <isl/union_map.h>
16 #include <isl_tarjan.h>
17 #include <isl_ast_private.h>
18 #include <isl_ast_build_expr.h>
19 #include <isl_ast_build_private.h>
20 #include <isl_ast_graft_private.h>
22 /* Add the constraint to the list that "user" points to, if it is not
25 static int collect_constraint(__isl_take isl_constraint
*constraint
,
28 isl_constraint_list
**list
= user
;
30 if (isl_constraint_is_div_constraint(constraint
))
31 isl_constraint_free(constraint
);
33 *list
= isl_constraint_list_add(*list
, constraint
);
38 /* Extract the constraints of "bset" (except the div constraints)
39 * and collect them in an isl_constraint_list.
41 static __isl_give isl_constraint_list
*isl_constraint_list_from_basic_set(
42 __isl_take isl_basic_set
*bset
)
46 isl_constraint_list
*list
;
51 ctx
= isl_basic_set_get_ctx(bset
);
53 n
= isl_basic_set_n_constraint(bset
);
54 list
= isl_constraint_list_alloc(ctx
, n
);
55 if (isl_basic_set_foreach_constraint(bset
,
56 &collect_constraint
, &list
) < 0)
57 list
= isl_constraint_list_free(list
);
59 isl_basic_set_free(bset
);
63 /* Data used in generate_domain.
65 * "build" is the input build.
66 * "list" collects the results.
68 struct isl_generate_domain_data
{
71 isl_ast_graft_list
*list
;
74 static __isl_give isl_ast_graft_list
*generate_next_level(
75 __isl_take isl_union_map
*executed
,
76 __isl_take isl_ast_build
*build
);
77 static __isl_give isl_ast_graft_list
*generate_code(
78 __isl_take isl_union_map
*executed
, __isl_take isl_ast_build
*build
,
81 /* Generate an AST for a single domain based on
82 * the (non single valued) inverse schedule "executed".
84 * We extend the schedule with the iteration domain
85 * and continue generating through a call to generate_code.
87 * In particular, if executed has the form
91 * then we continue generating code on
95 * The extended inverse schedule is clearly single valued
96 * ensuring that the nested generate_code will not reach this function,
97 * but will instead create calls to all elements of D that need
98 * to be executed from the current schedule domain.
100 static int generate_non_single_valued(__isl_take isl_map
*executed
,
101 struct isl_generate_domain_data
*data
)
104 isl_ast_build
*build
;
105 isl_ast_graft_list
*list
;
107 build
= isl_ast_build_copy(data
->build
);
109 identity
= isl_set_identity(isl_map_range(isl_map_copy(executed
)));
110 executed
= isl_map_domain_product(executed
, identity
);
111 build
= isl_ast_build_set_single_valued(build
, 1);
113 list
= generate_code(isl_union_map_from_map(executed
), build
, 1);
115 data
->list
= isl_ast_graft_list_concat(data
->list
, list
);
120 /* Call the at_each_domain callback, if requested by the user,
121 * after recording the current inverse schedule in the build.
123 static __isl_give isl_ast_graft
*at_each_domain(__isl_take isl_ast_graft
*graft
,
124 __isl_keep isl_map
*executed
, __isl_keep isl_ast_build
*build
)
126 if (!graft
|| !build
)
127 return isl_ast_graft_free(graft
);
128 if (!build
->at_each_domain
)
131 build
= isl_ast_build_copy(build
);
132 build
= isl_ast_build_set_executed(build
,
133 isl_union_map_from_map(isl_map_copy(executed
)));
135 return isl_ast_graft_free(graft
);
137 graft
->node
= build
->at_each_domain(graft
->node
,
138 build
, build
->at_each_domain_user
);
139 isl_ast_build_free(build
);
142 graft
= isl_ast_graft_free(graft
);
147 /* Generate an AST for a single domain based on
148 * the inverse schedule "executed".
150 * If there is more than one domain element associated to the current
151 * schedule "time", then we need to continue the generation process
152 * in generate_non_single_valued.
153 * Note that the inverse schedule being single-valued may depend
154 * on constraints that are only available in the original context
155 * domain specified by the user. We therefore first introduce
156 * the constraints from data->build->domain.
157 * On the other hand, we only perform the test after having taken the gist
158 * of the domain as the resulting map is the one from which the call
159 * expression is constructed. Using this map to construct the call
160 * expression usually yields simpler results.
161 * Because we perform the single-valuedness test on the gisted map,
162 * we may in rare cases fail to recognize that the inverse schedule
163 * is single-valued. This becomes problematic if this happens
164 * from the recursive call through generate_non_single_valued
165 * as we would then end up in an infinite recursion.
166 * We therefore check if we are inside a call to generate_non_single_valued
167 * and revert to the ungisted map if the gisted map turns out not to be
170 * Otherwise, we generate a call expression for the single executed
171 * domain element and put a guard around it based on the (simplified)
172 * domain of "executed".
174 * If the user has set an at_each_domain callback, it is called
175 * on the constructed call expression node.
177 static int generate_domain(__isl_take isl_map
*executed
, void *user
)
179 struct isl_generate_domain_data
*data
= user
;
180 isl_ast_graft
*graft
;
181 isl_ast_graft_list
*list
;
186 executed
= isl_map_intersect_domain(executed
,
187 isl_set_copy(data
->build
->domain
));
189 executed
= isl_map_coalesce(executed
);
190 map
= isl_map_copy(executed
);
191 map
= isl_ast_build_compute_gist_map_domain(data
->build
, map
);
192 sv
= isl_map_is_single_valued(map
);
197 if (data
->build
->single_valued
)
198 map
= isl_map_copy(executed
);
200 return generate_non_single_valued(executed
, data
);
202 guard
= isl_map_domain(isl_map_copy(map
));
203 guard
= isl_set_coalesce(guard
);
204 guard
= isl_ast_build_compute_gist(data
->build
, guard
);
205 graft
= isl_ast_graft_alloc_domain(map
, data
->build
);
206 graft
= at_each_domain(graft
, executed
, data
->build
);
208 isl_map_free(executed
);
209 graft
= isl_ast_graft_add_guard(graft
, guard
, data
->build
);
211 list
= isl_ast_graft_list_from_ast_graft(graft
);
212 data
->list
= isl_ast_graft_list_concat(data
->list
, list
);
217 isl_map_free(executed
);
221 /* Call build->create_leaf to a create "leaf" node in the AST,
222 * encapsulate the result in an isl_ast_graft and return the result
223 * as a 1-element list.
225 * Note that the node returned by the user may be an entire tree.
227 * Before we pass control to the user, we first clear some information
228 * from the build that is (presumbably) only meaningful
229 * for the current code generation.
230 * This includes the create_leaf callback itself, so we make a copy
231 * of the build first.
233 static __isl_give isl_ast_graft_list
*call_create_leaf(
234 __isl_take isl_union_map
*executed
, __isl_take isl_ast_build
*build
)
237 isl_ast_graft
*graft
;
238 isl_ast_build
*user_build
;
240 user_build
= isl_ast_build_copy(build
);
241 user_build
= isl_ast_build_set_executed(user_build
, executed
);
242 user_build
= isl_ast_build_clear_local_info(user_build
);
246 node
= build
->create_leaf(user_build
, build
->create_leaf_user
);
247 graft
= isl_ast_graft_alloc(node
, build
);
248 isl_ast_build_free(build
);
249 return isl_ast_graft_list_from_ast_graft(graft
);
252 /* Generate an AST after having handled the complete schedule
253 * of this call to the code generator.
255 * If the user has specified a create_leaf callback, control
256 * is passed to the user in call_create_leaf.
258 * Otherwise, we generate one or more calls for each individual
259 * domain in generate_domain.
261 static __isl_give isl_ast_graft_list
*generate_inner_level(
262 __isl_take isl_union_map
*executed
, __isl_take isl_ast_build
*build
)
265 struct isl_generate_domain_data data
= { build
};
267 if (!build
|| !executed
)
270 if (build
->create_leaf
)
271 return call_create_leaf(executed
, build
);
273 ctx
= isl_union_map_get_ctx(executed
);
274 data
.list
= isl_ast_graft_list_alloc(ctx
, 0);
275 if (isl_union_map_foreach_map(executed
, &generate_domain
, &data
) < 0)
276 data
.list
= isl_ast_graft_list_free(data
.list
);
279 error
: data
.list
= NULL
;
280 isl_ast_build_free(build
);
281 isl_union_map_free(executed
);
285 /* Call the before_each_for callback, if requested by the user.
287 static __isl_give isl_ast_node
*before_each_for(__isl_take isl_ast_node
*node
,
288 __isl_keep isl_ast_build
*build
)
293 return isl_ast_node_free(node
);
294 if (!build
->before_each_for
)
296 id
= build
->before_each_for(build
, build
->before_each_for_user
);
297 node
= isl_ast_node_set_annotation(node
, id
);
301 /* Call the after_each_for callback, if requested by the user.
303 static __isl_give isl_ast_graft
*after_each_for(__isl_keep isl_ast_graft
*graft
,
304 __isl_keep isl_ast_build
*build
)
306 if (!graft
|| !build
)
307 return isl_ast_graft_free(graft
);
308 if (!build
->after_each_for
)
310 graft
->node
= build
->after_each_for(graft
->node
, build
,
311 build
->after_each_for_user
);
313 return isl_ast_graft_free(graft
);
317 /* Plug in all the know values of the current and outer dimensions
318 * in the domain of "executed". In principle, we only need to plug
319 * in the known value of the current dimension since the values of
320 * outer dimensions have been plugged in already.
321 * However, it turns out to be easier to just plug in all known values.
323 static __isl_give isl_union_map
*plug_in_values(
324 __isl_take isl_union_map
*executed
, __isl_keep isl_ast_build
*build
)
326 return isl_ast_build_substitute_values_union_map_domain(build
,
330 /* Check if the constraint "c" is a lower bound on dimension "pos",
331 * an upper bound, or independent of dimension "pos".
333 static int constraint_type(isl_constraint
*c
, int pos
)
335 if (isl_constraint_is_lower_bound(c
, isl_dim_set
, pos
))
337 if (isl_constraint_is_upper_bound(c
, isl_dim_set
, pos
))
342 /* Compare the types of the constraints "a" and "b",
343 * resulting in constraints that are independent of "depth"
344 * to be sorted before the lower bounds on "depth", which in
345 * turn are sorted before the upper bounds on "depth".
347 static int cmp_constraint(__isl_keep isl_constraint
*a
,
348 __isl_keep isl_constraint
*b
, void *user
)
351 int t1
= constraint_type(a
, *depth
);
352 int t2
= constraint_type(b
, *depth
);
357 /* Extract a lower bound on dimension "pos" from constraint "c".
359 * If the constraint is of the form
363 * then we essentially return
365 * l = ceil(-f(...)/a)
367 * However, if the current dimension is strided, then we need to make
368 * sure that the lower bound we construct is of the form
372 * with f the offset and s the stride.
373 * We therefore compute
375 * f + s * ceil((l - f)/s)
377 static __isl_give isl_aff
*lower_bound(__isl_keep isl_constraint
*c
,
378 int pos
, __isl_keep isl_ast_build
*build
)
382 aff
= isl_constraint_get_bound(c
, isl_dim_set
, pos
);
383 aff
= isl_aff_ceil(aff
);
385 if (isl_ast_build_has_stride(build
, pos
)) {
389 offset
= isl_ast_build_get_offset(build
, pos
);
390 stride
= isl_ast_build_get_stride(build
, pos
);
392 aff
= isl_aff_sub(aff
, isl_aff_copy(offset
));
393 aff
= isl_aff_scale_down_val(aff
, isl_val_copy(stride
));
394 aff
= isl_aff_ceil(aff
);
395 aff
= isl_aff_scale_val(aff
, stride
);
396 aff
= isl_aff_add(aff
, offset
);
399 aff
= isl_ast_build_compute_gist_aff(build
, aff
);
404 /* Return the exact lower bound (or upper bound if "upper" is set)
405 * of "domain" as a piecewise affine expression.
407 * If we are computing a lower bound (of a strided dimension), then
408 * we need to make sure it is of the form
412 * where f is the offset and s is the stride.
413 * We therefore need to include the stride constraint before computing
416 static __isl_give isl_pw_aff
*exact_bound(__isl_keep isl_set
*domain
,
417 __isl_keep isl_ast_build
*build
, int upper
)
422 isl_pw_multi_aff
*pma
;
424 domain
= isl_set_copy(domain
);
426 stride
= isl_ast_build_get_stride_constraint(build
);
427 domain
= isl_set_intersect(domain
, stride
);
429 it_map
= isl_ast_build_map_to_iterator(build
, domain
);
431 pma
= isl_map_lexmax_pw_multi_aff(it_map
);
433 pma
= isl_map_lexmin_pw_multi_aff(it_map
);
434 pa
= isl_pw_multi_aff_get_pw_aff(pma
, 0);
435 isl_pw_multi_aff_free(pma
);
436 pa
= isl_ast_build_compute_gist_pw_aff(build
, pa
);
437 pa
= isl_pw_aff_coalesce(pa
);
442 /* Extract a lower bound on dimension "pos" from each constraint
443 * in "constraints" and return the list of lower bounds.
444 * If "constraints" has zero elements, then we extract a lower bound
445 * from "domain" instead.
447 static __isl_give isl_pw_aff_list
*lower_bounds(
448 __isl_keep isl_constraint_list
*constraints
, int pos
,
449 __isl_keep isl_set
*domain
, __isl_keep isl_ast_build
*build
)
452 isl_pw_aff_list
*list
;
458 n
= isl_constraint_list_n_constraint(constraints
);
461 pa
= exact_bound(domain
, build
, 0);
462 return isl_pw_aff_list_from_pw_aff(pa
);
465 ctx
= isl_ast_build_get_ctx(build
);
466 list
= isl_pw_aff_list_alloc(ctx
,n
);
468 for (i
= 0; i
< n
; ++i
) {
472 c
= isl_constraint_list_get_constraint(constraints
, i
);
473 aff
= lower_bound(c
, pos
, build
);
474 isl_constraint_free(c
);
475 list
= isl_pw_aff_list_add(list
, isl_pw_aff_from_aff(aff
));
481 /* Extract an upper bound on dimension "pos" from each constraint
482 * in "constraints" and return the list of upper bounds.
483 * If "constraints" has zero elements, then we extract an upper bound
484 * from "domain" instead.
486 static __isl_give isl_pw_aff_list
*upper_bounds(
487 __isl_keep isl_constraint_list
*constraints
, int pos
,
488 __isl_keep isl_set
*domain
, __isl_keep isl_ast_build
*build
)
491 isl_pw_aff_list
*list
;
494 n
= isl_constraint_list_n_constraint(constraints
);
497 pa
= exact_bound(domain
, build
, 1);
498 return isl_pw_aff_list_from_pw_aff(pa
);
501 ctx
= isl_ast_build_get_ctx(build
);
502 list
= isl_pw_aff_list_alloc(ctx
,n
);
504 for (i
= 0; i
< n
; ++i
) {
508 c
= isl_constraint_list_get_constraint(constraints
, i
);
509 aff
= isl_constraint_get_bound(c
, isl_dim_set
, pos
);
510 isl_constraint_free(c
);
511 aff
= isl_aff_floor(aff
);
512 list
= isl_pw_aff_list_add(list
, isl_pw_aff_from_aff(aff
));
518 /* Return an isl_ast_expr that performs the reduction of type "type"
519 * on AST expressions corresponding to the elements in "list".
521 * The list is assumed to contain at least one element.
522 * If the list contains exactly one element, then the returned isl_ast_expr
523 * simply computes that affine expression.
525 static __isl_give isl_ast_expr
*reduce_list(enum isl_ast_op_type type
,
526 __isl_keep isl_pw_aff_list
*list
, __isl_keep isl_ast_build
*build
)
535 n
= isl_pw_aff_list_n_pw_aff(list
);
538 return isl_ast_build_expr_from_pw_aff_internal(build
,
539 isl_pw_aff_list_get_pw_aff(list
, 0));
541 ctx
= isl_pw_aff_list_get_ctx(list
);
542 expr
= isl_ast_expr_alloc_op(ctx
, type
, n
);
546 for (i
= 0; i
< n
; ++i
) {
547 isl_ast_expr
*expr_i
;
549 expr_i
= isl_ast_build_expr_from_pw_aff_internal(build
,
550 isl_pw_aff_list_get_pw_aff(list
, i
));
552 return isl_ast_expr_free(expr
);
553 expr
->u
.op
.args
[i
] = expr_i
;
559 /* Add a guard to "graft" based on "bound" in the case of a degenerate
560 * level (including the special case of an eliminated level).
562 * We eliminate the current dimension, simplify the result in the current
563 * build and add the result as guards to the graft.
565 * Note that we cannot simply drop the constraints on the current dimension
566 * even in the eliminated case, because the single affine expression may
567 * not be explicitly available in "bounds". Moreover, the single affine
568 * expression may only be defined on a subset of the build domain,
569 * so we do in some cases need to insert a guard even in the eliminated case.
571 static __isl_give isl_ast_graft
*add_degenerate_guard(
572 __isl_take isl_ast_graft
*graft
, __isl_keep isl_basic_set
*bounds
,
573 __isl_keep isl_ast_build
*build
)
578 depth
= isl_ast_build_get_depth(build
);
580 dom
= isl_set_from_basic_set(isl_basic_set_copy(bounds
));
581 if (isl_ast_build_has_stride(build
, depth
)) {
584 stride
= isl_ast_build_get_stride_constraint(build
);
585 dom
= isl_set_intersect(dom
, stride
);
587 dom
= isl_set_eliminate(dom
, isl_dim_set
, depth
, 1);
588 dom
= isl_ast_build_compute_gist(build
, dom
);
590 graft
= isl_ast_graft_add_guard(graft
, dom
, build
);
595 /* Update "graft" based on "bounds" for the eliminated case.
597 * In the eliminated case, no for node is created, so we only need
598 * to check if "bounds" imply any guards that need to be inserted.
600 static __isl_give isl_ast_graft
*refine_eliminated(
601 __isl_take isl_ast_graft
*graft
, __isl_keep isl_basic_set
*bounds
,
602 __isl_keep isl_ast_build
*build
)
604 return add_degenerate_guard(graft
, bounds
, build
);
607 /* Update "graft" based on "bounds" and "sub_build" for the degenerate case.
609 * "build" is the build in which graft->node was created
610 * "sub_build" contains information about the current level itself,
611 * including the single value attained.
613 * We first set the initialization part of the for loop to the single
614 * value attained by the current dimension.
615 * The increment and condition are not strictly needed as the are known
616 * to be "1" and "iterator <= value" respectively.
617 * Then we set the size of the iterator and
618 * check if "bounds" imply any guards that need to be inserted.
620 static __isl_give isl_ast_graft
*refine_degenerate(
621 __isl_take isl_ast_graft
*graft
, __isl_keep isl_basic_set
*bounds
,
622 __isl_keep isl_ast_build
*build
,
623 __isl_keep isl_ast_build
*sub_build
)
627 if (!graft
|| !sub_build
)
628 return isl_ast_graft_free(graft
);
630 value
= isl_pw_aff_copy(sub_build
->value
);
632 graft
->node
->u
.f
.init
= isl_ast_build_expr_from_pw_aff_internal(build
,
634 if (!graft
->node
->u
.f
.init
)
635 return isl_ast_graft_free(graft
);
637 graft
= add_degenerate_guard(graft
, bounds
, build
);
642 /* Return the intersection of constraints in "list" as a set.
644 static __isl_give isl_set
*intersect_constraints(
645 __isl_keep isl_constraint_list
*list
)
650 n
= isl_constraint_list_n_constraint(list
);
652 isl_die(isl_constraint_list_get_ctx(list
), isl_error_internal
,
653 "expecting at least one constraint", return NULL
);
655 bset
= isl_basic_set_from_constraint(
656 isl_constraint_list_get_constraint(list
, 0));
657 for (i
= 1; i
< n
; ++i
) {
658 isl_basic_set
*bset_i
;
660 bset_i
= isl_basic_set_from_constraint(
661 isl_constraint_list_get_constraint(list
, i
));
662 bset
= isl_basic_set_intersect(bset
, bset_i
);
665 return isl_set_from_basic_set(bset
);
668 /* Compute the constraints on the outer dimensions enforced by
669 * graft->node and add those constraints to graft->enforced,
670 * in case the upper bound is expressed as a set "upper".
672 * In particular, if l(...) is a lower bound in "lower", and
674 * -a i + f(...) >= 0 or a i <= f(...)
676 * is an upper bound ocnstraint on the current dimension i,
677 * then the for loop enforces the constraint
679 * -a l(...) + f(...) >= 0 or a l(...) <= f(...)
681 * We therefore simply take each lower bound in turn, plug it into
682 * the upper bounds and compute the intersection over all lower bounds.
684 * If a lower bound is a rational expression, then
685 * isl_basic_set_preimage_multi_aff will force this rational
686 * expression to have only integer values. However, the loop
687 * itself does not enforce this integrality constraint. We therefore
688 * use the ceil of the lower bounds instead of the lower bounds themselves.
689 * Other constraints will make sure that the for loop is only executed
690 * when each of the lower bounds attains an integral value.
691 * In particular, potentially rational values only occur in
692 * lower_bound if the offset is a (seemingly) rational expression,
693 * but then outer conditions will make sure that this rational expression
694 * only attains integer values.
696 static __isl_give isl_ast_graft
*set_enforced_from_set(
697 __isl_take isl_ast_graft
*graft
,
698 __isl_keep isl_pw_aff_list
*lower
, int pos
, __isl_keep isl_set
*upper
)
701 isl_basic_set
*enforced
;
702 isl_pw_multi_aff
*pma
;
705 if (!graft
|| !lower
)
706 return isl_ast_graft_free(graft
);
708 space
= isl_set_get_space(upper
);
709 enforced
= isl_basic_set_universe(isl_space_copy(space
));
711 space
= isl_space_map_from_set(space
);
712 pma
= isl_pw_multi_aff_identity(space
);
714 n
= isl_pw_aff_list_n_pw_aff(lower
);
715 for (i
= 0; i
< n
; ++i
) {
719 isl_pw_multi_aff
*pma_i
;
721 pa
= isl_pw_aff_list_get_pw_aff(lower
, i
);
722 pa
= isl_pw_aff_ceil(pa
);
723 pma_i
= isl_pw_multi_aff_copy(pma
);
724 pma_i
= isl_pw_multi_aff_set_pw_aff(pma_i
, pos
, pa
);
725 enforced_i
= isl_set_copy(upper
);
726 enforced_i
= isl_set_preimage_pw_multi_aff(enforced_i
, pma_i
);
727 hull
= isl_set_simple_hull(enforced_i
);
728 enforced
= isl_basic_set_intersect(enforced
, hull
);
731 isl_pw_multi_aff_free(pma
);
733 graft
= isl_ast_graft_enforce(graft
, enforced
);
738 /* Compute the constraints on the outer dimensions enforced by
739 * graft->node and add those constraints to graft->enforced,
740 * in case the upper bound is expressed as
741 * a list of affine expressions "upper".
743 * The enforced condition is that each lower bound expression is less
744 * than or equal to each upper bound expression.
746 static __isl_give isl_ast_graft
*set_enforced_from_list(
747 __isl_take isl_ast_graft
*graft
,
748 __isl_keep isl_pw_aff_list
*lower
, __isl_keep isl_pw_aff_list
*upper
)
751 isl_basic_set
*enforced
;
753 lower
= isl_pw_aff_list_copy(lower
);
754 upper
= isl_pw_aff_list_copy(upper
);
755 cond
= isl_pw_aff_list_le_set(lower
, upper
);
756 enforced
= isl_set_simple_hull(cond
);
757 graft
= isl_ast_graft_enforce(graft
, enforced
);
762 /* Does "aff" have a negative constant term?
764 static int aff_constant_is_negative(__isl_take isl_set
*set
,
765 __isl_take isl_aff
*aff
, void *user
)
770 v
= isl_aff_get_constant_val(aff
);
771 *neg
= isl_val_is_neg(v
);
776 return *neg
? 0 : -1;
779 /* Does "pa" have a negative constant term over its entire domain?
781 static int pw_aff_constant_is_negative(__isl_take isl_pw_aff
*pa
, void *user
)
786 r
= isl_pw_aff_foreach_piece(pa
, &aff_constant_is_negative
, user
);
789 return *neg
? 0 : -1;
792 /* Does each element in "list" have a negative constant term?
794 * The callback terminates the iteration as soon an element has been
795 * found that does not have a negative constant term.
797 static int list_constant_is_negative(__isl_keep isl_pw_aff_list
*list
)
801 if (isl_pw_aff_list_foreach(list
,
802 &pw_aff_constant_is_negative
, &neg
) < 0 && neg
)
808 /* Add 1 to each of the elements in "list", where each of these elements
809 * is defined over the internal schedule space of "build".
811 static __isl_give isl_pw_aff_list
*list_add_one(
812 __isl_take isl_pw_aff_list
*list
, __isl_keep isl_ast_build
*build
)
819 space
= isl_ast_build_get_space(build
, 1);
820 aff
= isl_aff_zero_on_domain(isl_local_space_from_space(space
));
821 aff
= isl_aff_add_constant_si(aff
, 1);
822 one
= isl_pw_aff_from_aff(aff
);
824 n
= isl_pw_aff_list_n_pw_aff(list
);
825 for (i
= 0; i
< n
; ++i
) {
827 pa
= isl_pw_aff_list_get_pw_aff(list
, i
);
828 pa
= isl_pw_aff_add(pa
, isl_pw_aff_copy(one
));
829 list
= isl_pw_aff_list_set_pw_aff(list
, i
, pa
);
832 isl_pw_aff_free(one
);
837 /* Set the condition part of the for node graft->node in case
838 * the upper bound is represented as a list of piecewise affine expressions.
840 * In particular, set the condition to
842 * iterator <= min(list of upper bounds)
844 * If each of the upper bounds has a negative constant term, then
845 * set the condition to
847 * iterator < min(list of (upper bound + 1)s)
850 static __isl_give isl_ast_graft
*set_for_cond_from_list(
851 __isl_take isl_ast_graft
*graft
, __isl_keep isl_pw_aff_list
*list
,
852 __isl_keep isl_ast_build
*build
)
855 isl_ast_expr
*bound
, *iterator
, *cond
;
856 enum isl_ast_op_type type
= isl_ast_op_le
;
859 return isl_ast_graft_free(graft
);
861 neg
= list_constant_is_negative(list
);
863 return isl_ast_graft_free(graft
);
864 list
= isl_pw_aff_list_copy(list
);
866 list
= list_add_one(list
, build
);
867 type
= isl_ast_op_lt
;
870 bound
= reduce_list(isl_ast_op_min
, list
, build
);
871 iterator
= isl_ast_expr_copy(graft
->node
->u
.f
.iterator
);
872 cond
= isl_ast_expr_alloc_binary(type
, iterator
, bound
);
873 graft
->node
->u
.f
.cond
= cond
;
875 isl_pw_aff_list_free(list
);
876 if (!graft
->node
->u
.f
.cond
)
877 return isl_ast_graft_free(graft
);
881 /* Set the condition part of the for node graft->node in case
882 * the upper bound is represented as a set.
884 static __isl_give isl_ast_graft
*set_for_cond_from_set(
885 __isl_take isl_ast_graft
*graft
, __isl_keep isl_set
*set
,
886 __isl_keep isl_ast_build
*build
)
893 cond
= isl_ast_build_expr_from_set(build
, isl_set_copy(set
));
894 graft
->node
->u
.f
.cond
= cond
;
895 if (!graft
->node
->u
.f
.cond
)
896 return isl_ast_graft_free(graft
);
900 /* Construct an isl_ast_expr for the increment (i.e., stride) of
901 * the current dimension.
903 static __isl_give isl_ast_expr
*for_inc(__isl_keep isl_ast_build
*build
)
911 ctx
= isl_ast_build_get_ctx(build
);
912 depth
= isl_ast_build_get_depth(build
);
914 if (!isl_ast_build_has_stride(build
, depth
))
915 return isl_ast_expr_alloc_int_si(ctx
, 1);
917 v
= isl_ast_build_get_stride(build
, depth
);
918 return isl_ast_expr_from_val(v
);
921 /* Should we express the loop condition as
923 * iterator <= min(list of upper bounds)
925 * or as a conjunction of constraints?
927 * The first is constructed from a list of upper bounds.
928 * The second is constructed from a set.
930 * If there are no upper bounds in "constraints", then this could mean
931 * that "domain" simply doesn't have an upper bound or that we didn't
932 * pick any upper bound. In the first case, we want to generate the
933 * loop condition as a(n empty) conjunction of constraints
934 * In the second case, we will compute
935 * a single upper bound from "domain" and so we use the list form.
937 * If there are upper bounds in "constraints",
938 * then we use the list form iff the atomic_upper_bound option is set.
940 static int use_upper_bound_list(isl_ctx
*ctx
, int n_upper
,
941 __isl_keep isl_set
*domain
, int depth
)
944 return isl_options_get_ast_build_atomic_upper_bound(ctx
);
946 return isl_set_dim_has_upper_bound(domain
, isl_dim_set
, depth
);
949 /* Fill in the expressions of the for node in graft->node.
952 * - set the initialization part of the loop to the maximum of the lower bounds
953 * - set the size of the iterator based on the values attained by the iterator
954 * - extract the increment from the stride of the current dimension
955 * - construct the for condition either based on a list of upper bounds
956 * or on a set of upper bound constraints.
958 static __isl_give isl_ast_graft
*set_for_node_expressions(
959 __isl_take isl_ast_graft
*graft
, __isl_keep isl_pw_aff_list
*lower
,
960 int use_list
, __isl_keep isl_pw_aff_list
*upper_list
,
961 __isl_keep isl_set
*upper_set
, __isl_keep isl_ast_build
*build
)
968 build
= isl_ast_build_copy(build
);
969 build
= isl_ast_build_set_enforced(build
,
970 isl_ast_graft_get_enforced(graft
));
973 node
->u
.f
.init
= reduce_list(isl_ast_op_max
, lower
, build
);
974 node
->u
.f
.inc
= for_inc(build
);
977 graft
= set_for_cond_from_list(graft
, upper_list
, build
);
979 graft
= set_for_cond_from_set(graft
, upper_set
, build
);
981 isl_ast_build_free(build
);
983 if (!node
->u
.f
.iterator
|| !node
->u
.f
.init
||
984 !node
->u
.f
.cond
|| !node
->u
.f
.inc
)
985 return isl_ast_graft_free(graft
);
990 /* Update "graft" based on "bounds" and "domain" for the generic,
991 * non-degenerate, case.
993 * "c_lower" and "c_upper" contain the lower and upper bounds
994 * that the loop node should express.
995 * "domain" is the subset of the intersection of the constraints
996 * for which some code is executed.
998 * There may be zero lower bounds or zero upper bounds in "constraints"
999 * in case the list of constraints was created
1000 * based on the atomic option or based on separation with explicit bounds.
1001 * In that case, we use "domain" to derive lower and/or upper bounds.
1003 * We first compute a list of one or more lower bounds.
1005 * Then we decide if we want to express the condition as
1007 * iterator <= min(list of upper bounds)
1009 * or as a conjunction of constraints.
1011 * The set of enforced constraints is then computed either based on
1012 * a list of upper bounds or on a set of upper bound constraints.
1013 * We do not compute any enforced constraints if we were forced
1014 * to compute a lower or upper bound using exact_bound. The domains
1015 * of the resulting expressions may imply some bounds on outer dimensions
1016 * that we do not want to appear in the enforced constraints since
1017 * they are not actually enforced by the corresponding code.
1019 * Finally, we fill in the expressions of the for node.
1021 static __isl_give isl_ast_graft
*refine_generic_bounds(
1022 __isl_take isl_ast_graft
*graft
,
1023 __isl_take isl_constraint_list
*c_lower
,
1024 __isl_take isl_constraint_list
*c_upper
,
1025 __isl_keep isl_set
*domain
, __isl_keep isl_ast_build
*build
)
1029 isl_pw_aff_list
*lower
;
1031 isl_set
*upper_set
= NULL
;
1032 isl_pw_aff_list
*upper_list
= NULL
;
1033 int n_lower
, n_upper
;
1035 if (!graft
|| !c_lower
|| !c_upper
|| !build
)
1038 depth
= isl_ast_build_get_depth(build
);
1039 ctx
= isl_ast_graft_get_ctx(graft
);
1041 n_lower
= isl_constraint_list_n_constraint(c_lower
);
1042 n_upper
= isl_constraint_list_n_constraint(c_upper
);
1044 use_list
= use_upper_bound_list(ctx
, n_upper
, domain
, depth
);
1046 lower
= lower_bounds(c_lower
, depth
, domain
, build
);
1049 upper_list
= upper_bounds(c_upper
, depth
, domain
, build
);
1050 else if (n_upper
> 0)
1051 upper_set
= intersect_constraints(c_upper
);
1053 upper_set
= isl_set_universe(isl_set_get_space(domain
));
1055 if (n_lower
== 0 || n_upper
== 0)
1058 graft
= set_enforced_from_list(graft
, lower
, upper_list
);
1060 graft
= set_enforced_from_set(graft
, lower
, depth
, upper_set
);
1062 graft
= set_for_node_expressions(graft
, lower
, use_list
, upper_list
,
1065 isl_pw_aff_list_free(lower
);
1066 isl_pw_aff_list_free(upper_list
);
1067 isl_set_free(upper_set
);
1068 isl_constraint_list_free(c_lower
);
1069 isl_constraint_list_free(c_upper
);
1073 isl_constraint_list_free(c_lower
);
1074 isl_constraint_list_free(c_upper
);
1075 return isl_ast_graft_free(graft
);
1078 /* Internal data structure used inside count_constraints to keep
1079 * track of the number of constraints that are independent of dimension "pos",
1080 * the lower bounds in "pos" and the upper bounds in "pos".
1082 struct isl_ast_count_constraints_data
{
1090 /* Increment data->n_indep, data->lower or data->upper depending
1091 * on whether "c" is independenct of dimensions data->pos,
1092 * a lower bound or an upper bound.
1094 static int count_constraints(__isl_take isl_constraint
*c
, void *user
)
1096 struct isl_ast_count_constraints_data
*data
= user
;
1098 if (isl_constraint_is_lower_bound(c
, isl_dim_set
, data
->pos
))
1100 else if (isl_constraint_is_upper_bound(c
, isl_dim_set
, data
->pos
))
1105 isl_constraint_free(c
);
1110 /* Update "graft" based on "bounds" and "domain" for the generic,
1111 * non-degenerate, case.
1113 * "list" respresent the list of bounds that need to be encoded by
1114 * the for loop (or a guard around the for loop).
1115 * "domain" is the subset of the intersection of the constraints
1116 * for which some code is executed.
1117 * "build" is the build in which graft->node was created.
1119 * We separate lower bounds, upper bounds and constraints that
1120 * are independent of the loop iterator.
1122 * The actual for loop bounds are generated in refine_generic_bounds.
1123 * If there are any constraints that are independent of the loop iterator,
1124 * we need to put a guard around the for loop (which may get hoisted up
1125 * to higher levels) and we call refine_generic_bounds in a build
1126 * where this guard is enforced.
1128 static __isl_give isl_ast_graft
*refine_generic_split(
1129 __isl_take isl_ast_graft
*graft
, __isl_take isl_constraint_list
*list
,
1130 __isl_keep isl_set
*domain
, __isl_keep isl_ast_build
*build
)
1132 isl_ast_build
*for_build
;
1134 struct isl_ast_count_constraints_data data
;
1135 isl_constraint_list
*lower
;
1136 isl_constraint_list
*upper
;
1139 return isl_ast_graft_free(graft
);
1141 data
.pos
= isl_ast_build_get_depth(build
);
1143 list
= isl_constraint_list_sort(list
, &cmp_constraint
, &data
.pos
);
1145 return isl_ast_graft_free(graft
);
1147 data
.n_indep
= data
.n_lower
= data
.n_upper
= 0;
1148 if (isl_constraint_list_foreach(list
, &count_constraints
, &data
) < 0) {
1149 isl_constraint_list_free(list
);
1150 return isl_ast_graft_free(graft
);
1153 lower
= isl_constraint_list_copy(list
);
1154 lower
= isl_constraint_list_drop(lower
, 0, data
.n_indep
);
1155 upper
= isl_constraint_list_copy(lower
);
1156 lower
= isl_constraint_list_drop(lower
, data
.n_lower
, data
.n_upper
);
1157 upper
= isl_constraint_list_drop(upper
, 0, data
.n_lower
);
1159 if (data
.n_indep
== 0) {
1160 isl_constraint_list_free(list
);
1161 return refine_generic_bounds(graft
, lower
, upper
,
1165 list
= isl_constraint_list_drop(list
, data
.n_indep
,
1166 data
.n_lower
+ data
.n_upper
);
1167 guard
= intersect_constraints(list
);
1168 isl_constraint_list_free(list
);
1170 for_build
= isl_ast_build_copy(build
);
1171 for_build
= isl_ast_build_restrict_pending(for_build
,
1172 isl_set_copy(guard
));
1173 graft
= refine_generic_bounds(graft
, lower
, upper
, domain
, for_build
);
1174 isl_ast_build_free(for_build
);
1176 graft
= isl_ast_graft_add_guard(graft
, guard
, build
);
1181 /* Add the guard implied by the current stride constraint (if any),
1182 * but not (necessarily) enforced by the generated AST to "graft".
1184 static __isl_give isl_ast_graft
*add_stride_guard(
1185 __isl_take isl_ast_graft
*graft
, __isl_keep isl_ast_build
*build
)
1190 depth
= isl_ast_build_get_depth(build
);
1191 if (!isl_ast_build_has_stride(build
, depth
))
1194 dom
= isl_ast_build_get_stride_constraint(build
);
1195 dom
= isl_set_eliminate(dom
, isl_dim_set
, depth
, 1);
1196 dom
= isl_ast_build_compute_gist(build
, dom
);
1198 graft
= isl_ast_graft_add_guard(graft
, dom
, build
);
1203 /* Update "graft" based on "bounds" and "domain" for the generic,
1204 * non-degenerate, case.
1206 * "bounds" respresent the bounds that need to be encoded by
1207 * the for loop (or a guard around the for loop).
1208 * "domain" is the subset of "bounds" for which some code is executed.
1209 * "build" is the build in which graft->node was created.
1211 * We break up "bounds" into a list of constraints and continue with
1212 * refine_generic_split.
1214 static __isl_give isl_ast_graft
*refine_generic(
1215 __isl_take isl_ast_graft
*graft
,
1216 __isl_keep isl_basic_set
*bounds
, __isl_keep isl_set
*domain
,
1217 __isl_keep isl_ast_build
*build
)
1219 isl_constraint_list
*list
;
1221 if (!build
|| !graft
)
1222 return isl_ast_graft_free(graft
);
1224 bounds
= isl_basic_set_copy(bounds
);
1225 bounds
= isl_ast_build_compute_gist_basic_set(build
, bounds
);
1226 list
= isl_constraint_list_from_basic_set(bounds
);
1228 graft
= refine_generic_split(graft
, list
, domain
, build
);
1229 graft
= add_stride_guard(graft
, build
);
1234 /* Create a for node for the current level.
1236 * Mark the for node degenerate if "degenerate" is set.
1238 static __isl_give isl_ast_node
*create_for(__isl_keep isl_ast_build
*build
,
1248 depth
= isl_ast_build_get_depth(build
);
1249 id
= isl_ast_build_get_iterator_id(build
, depth
);
1250 node
= isl_ast_node_alloc_for(id
);
1252 node
= isl_ast_node_for_mark_degenerate(node
);
1257 /* Create an AST node for the current dimension based on
1258 * the schedule domain "bounds" and return the node encapsulated
1259 * in an isl_ast_graft.
1261 * "executed" is the current inverse schedule, taking into account
1262 * the bounds in "bounds"
1263 * "domain" is the domain of "executed", with inner dimensions projected out.
1264 * It may be a strict subset of "bounds" in case "bounds" was created
1265 * based on the atomic option or based on separation with explicit bounds.
1267 * "domain" may satisfy additional equalities that result
1268 * from intersecting "executed" with "bounds" in add_node.
1269 * It may also satisfy some global constraints that were dropped out because
1270 * we performed separation with explicit bounds.
1271 * The very first step is then to copy these constraints to "bounds".
1273 * Since we may be calling before_each_for and after_each_for
1274 * callbacks, we record the current inverse schedule in the build.
1276 * We consider three builds,
1277 * "build" is the one in which the current level is created,
1278 * "body_build" is the build in which the next level is created,
1279 * "sub_build" is essentially the same as "body_build", except that
1280 * the depth has not been increased yet.
1282 * "build" already contains information (in strides and offsets)
1283 * about the strides at the current level, but this information is not
1284 * reflected in the build->domain.
1285 * We first add this information and the "bounds" to the sub_build->domain.
1286 * isl_ast_build_set_loop_bounds checks whether the current dimension attains
1287 * only a single value and whether this single value can be represented using
1288 * a single affine expression.
1289 * In the first case, the current level is considered "degenerate".
1290 * In the second, sub-case, the current level is considered "eliminated".
1291 * Eliminated level don't need to be reflected in the AST since we can
1292 * simply plug in the affine expression. For degenerate, but non-eliminated,
1293 * levels, we do introduce a for node, but mark is as degenerate so that
1294 * it can be printed as an assignment of the single value to the loop
1297 * If the current level is eliminated, we explicitly plug in the value
1298 * for the current level found by isl_ast_build_set_loop_bounds in the
1299 * inverse schedule. This ensures that if we are working on a slice
1300 * of the domain based on information available in the inverse schedule
1301 * and the build domain, that then this information is also reflected
1302 * in the inverse schedule. This operation also eliminates the current
1303 * dimension from the inverse schedule making sure no inner dimensions depend
1304 * on the current dimension. Otherwise, we create a for node, marking
1305 * it degenerate if appropriate. The initial for node is still incomplete
1306 * and will be completed in either refine_degenerate or refine_generic.
1308 * We then generate a sequence of grafts for the next level,
1309 * create a surrounding graft for the current level and insert
1310 * the for node we created (if the current level is not eliminated).
1312 * Finally, we set the bounds of the for loop and insert guards
1313 * (either in the AST or in the graft) in one of
1314 * refine_eliminated, refine_degenerate or refine_generic.
1316 static __isl_give isl_ast_graft
*create_node_scaled(
1317 __isl_take isl_union_map
*executed
,
1318 __isl_take isl_basic_set
*bounds
, __isl_take isl_set
*domain
,
1319 __isl_take isl_ast_build
*build
)
1322 int degenerate
, eliminated
;
1323 isl_basic_set
*hull
;
1324 isl_ast_node
*node
= NULL
;
1325 isl_ast_graft
*graft
;
1326 isl_ast_graft_list
*children
;
1327 isl_ast_build
*sub_build
;
1328 isl_ast_build
*body_build
;
1330 domain
= isl_ast_build_eliminate_divs(build
, domain
);
1331 domain
= isl_set_detect_equalities(domain
);
1332 hull
= isl_set_unshifted_simple_hull(isl_set_copy(domain
));
1333 bounds
= isl_basic_set_intersect(bounds
, hull
);
1334 build
= isl_ast_build_set_executed(build
, isl_union_map_copy(executed
));
1336 depth
= isl_ast_build_get_depth(build
);
1337 sub_build
= isl_ast_build_copy(build
);
1338 sub_build
= isl_ast_build_include_stride(sub_build
);
1339 sub_build
= isl_ast_build_set_loop_bounds(sub_build
,
1340 isl_basic_set_copy(bounds
));
1341 degenerate
= isl_ast_build_has_value(sub_build
);
1342 eliminated
= isl_ast_build_has_affine_value(sub_build
, depth
);
1343 if (degenerate
< 0 || eliminated
< 0)
1344 executed
= isl_union_map_free(executed
);
1346 executed
= plug_in_values(executed
, sub_build
);
1348 node
= create_for(build
, degenerate
);
1350 body_build
= isl_ast_build_copy(sub_build
);
1351 body_build
= isl_ast_build_increase_depth(body_build
);
1353 node
= before_each_for(node
, body_build
);
1354 children
= generate_next_level(executed
,
1355 isl_ast_build_copy(body_build
));
1357 graft
= isl_ast_graft_alloc_level(children
, build
, sub_build
);
1359 graft
= isl_ast_graft_insert_for(graft
, node
);
1361 graft
= refine_eliminated(graft
, bounds
, build
);
1362 else if (degenerate
)
1363 graft
= refine_degenerate(graft
, bounds
, build
, sub_build
);
1365 graft
= refine_generic(graft
, bounds
, domain
, build
);
1367 graft
= after_each_for(graft
, body_build
);
1369 isl_ast_build_free(body_build
);
1370 isl_ast_build_free(sub_build
);
1371 isl_ast_build_free(build
);
1372 isl_basic_set_free(bounds
);
1373 isl_set_free(domain
);
1378 /* Internal data structure for checking if all constraints involving
1379 * the input dimension "depth" are such that the other coefficients
1380 * are multiples of "m", reducing "m" if they are not.
1381 * If "m" is reduced all the way down to "1", then the check has failed
1382 * and we break out of the iteration.
1384 struct isl_check_scaled_data
{
1389 /* If constraint "c" involves the input dimension data->depth,
1390 * then make sure that all the other coefficients are multiples of data->m,
1391 * reducing data->m if needed.
1392 * Break out of the iteration if data->m has become equal to "1".
1394 static int constraint_check_scaled(__isl_take isl_constraint
*c
, void *user
)
1396 struct isl_check_scaled_data
*data
= user
;
1398 enum isl_dim_type t
[] = { isl_dim_param
, isl_dim_in
, isl_dim_out
,
1401 if (!isl_constraint_involves_dims(c
, isl_dim_in
, data
->depth
, 1)) {
1402 isl_constraint_free(c
);
1406 for (i
= 0; i
< 4; ++i
) {
1407 n
= isl_constraint_dim(c
, t
[i
]);
1408 for (j
= 0; j
< n
; ++j
) {
1411 if (t
[i
] == isl_dim_in
&& j
== data
->depth
)
1413 if (!isl_constraint_involves_dims(c
, t
[i
], j
, 1))
1415 d
= isl_constraint_get_coefficient_val(c
, t
[i
], j
);
1416 data
->m
= isl_val_gcd(data
->m
, d
);
1417 if (isl_val_is_one(data
->m
))
1424 isl_constraint_free(c
);
1426 return i
< 4 ? -1 : 0;
1429 /* For each constraint of "bmap" that involves the input dimension data->depth,
1430 * make sure that all the other coefficients are multiples of data->m,
1431 * reducing data->m if needed.
1432 * Break out of the iteration if data->m has become equal to "1".
1434 static int basic_map_check_scaled(__isl_take isl_basic_map
*bmap
, void *user
)
1438 r
= isl_basic_map_foreach_constraint(bmap
,
1439 &constraint_check_scaled
, user
);
1440 isl_basic_map_free(bmap
);
1445 /* For each constraint of "map" that involves the input dimension data->depth,
1446 * make sure that all the other coefficients are multiples of data->m,
1447 * reducing data->m if needed.
1448 * Break out of the iteration if data->m has become equal to "1".
1450 static int map_check_scaled(__isl_take isl_map
*map
, void *user
)
1454 r
= isl_map_foreach_basic_map(map
, &basic_map_check_scaled
, user
);
1460 /* Create an AST node for the current dimension based on
1461 * the schedule domain "bounds" and return the node encapsulated
1462 * in an isl_ast_graft.
1464 * "executed" is the current inverse schedule, taking into account
1465 * the bounds in "bounds"
1466 * "domain" is the domain of "executed", with inner dimensions projected out.
1469 * Before moving on to the actual AST node construction in create_node_scaled,
1470 * we first check if the current dimension is strided and if we can scale
1471 * down this stride. Note that we only do this if the ast_build_scale_strides
1474 * In particular, let the current dimension take on values
1478 * with a an integer. We check if we can find an integer m that (obviouly)
1479 * divides both f and s.
1481 * If so, we check if the current dimension only appears in constraints
1482 * where the coefficients of the other variables are multiples of m.
1483 * We perform this extra check to avoid the risk of introducing
1484 * divisions by scaling down the current dimension.
1486 * If so, we scale the current dimension down by a factor of m.
1487 * That is, we plug in
1491 * Note that in principle we could always scale down strided loops
1496 * but this may result in i' taking on larger values than the original i,
1497 * due to the shift by "f".
1498 * By constrast, the scaling in (1) can only reduce the (absolute) value "i".
1500 static __isl_give isl_ast_graft
*create_node(__isl_take isl_union_map
*executed
,
1501 __isl_take isl_basic_set
*bounds
, __isl_take isl_set
*domain
,
1502 __isl_take isl_ast_build
*build
)
1504 struct isl_check_scaled_data data
;
1509 ctx
= isl_ast_build_get_ctx(build
);
1510 if (!isl_options_get_ast_build_scale_strides(ctx
))
1511 return create_node_scaled(executed
, bounds
, domain
, build
);
1513 data
.depth
= isl_ast_build_get_depth(build
);
1514 if (!isl_ast_build_has_stride(build
, data
.depth
))
1515 return create_node_scaled(executed
, bounds
, domain
, build
);
1517 offset
= isl_ast_build_get_offset(build
, data
.depth
);
1518 data
.m
= isl_ast_build_get_stride(build
, data
.depth
);
1520 offset
= isl_aff_free(offset
);
1521 offset
= isl_aff_scale_down_val(offset
, isl_val_copy(data
.m
));
1522 d
= isl_aff_get_denominator_val(offset
);
1524 executed
= isl_union_map_free(executed
);
1526 if (executed
&& isl_val_is_divisible_by(data
.m
, d
))
1527 data
.m
= isl_val_div(data
.m
, d
);
1529 data
.m
= isl_val_set_si(data
.m
, 1);
1533 if (!isl_val_is_one(data
.m
)) {
1534 if (isl_union_map_foreach_map(executed
, &map_check_scaled
,
1536 !isl_val_is_one(data
.m
))
1537 executed
= isl_union_map_free(executed
);
1540 if (!isl_val_is_one(data
.m
)) {
1545 isl_union_map
*umap
;
1547 space
= isl_ast_build_get_space(build
, 1);
1548 space
= isl_space_map_from_set(space
);
1549 ma
= isl_multi_aff_identity(space
);
1550 aff
= isl_multi_aff_get_aff(ma
, data
.depth
);
1551 aff
= isl_aff_scale_val(aff
, isl_val_copy(data
.m
));
1552 ma
= isl_multi_aff_set_aff(ma
, data
.depth
, aff
);
1554 bounds
= isl_basic_set_preimage_multi_aff(bounds
,
1555 isl_multi_aff_copy(ma
));
1556 domain
= isl_set_preimage_multi_aff(domain
,
1557 isl_multi_aff_copy(ma
));
1558 map
= isl_map_reverse(isl_map_from_multi_aff(ma
));
1559 umap
= isl_union_map_from_map(map
);
1560 executed
= isl_union_map_apply_domain(executed
,
1561 isl_union_map_copy(umap
));
1562 build
= isl_ast_build_scale_down(build
, isl_val_copy(data
.m
),
1565 isl_aff_free(offset
);
1566 isl_val_free(data
.m
);
1568 return create_node_scaled(executed
, bounds
, domain
, build
);
1571 /* Add the basic set to the list that "user" points to.
1573 static int collect_basic_set(__isl_take isl_basic_set
*bset
, void *user
)
1575 isl_basic_set_list
**list
= user
;
1577 *list
= isl_basic_set_list_add(*list
, bset
);
1582 /* Extract the basic sets of "set" and collect them in an isl_basic_set_list.
1584 static __isl_give isl_basic_set_list
*isl_basic_set_list_from_set(
1585 __isl_take isl_set
*set
)
1589 isl_basic_set_list
*list
;
1594 ctx
= isl_set_get_ctx(set
);
1596 n
= isl_set_n_basic_set(set
);
1597 list
= isl_basic_set_list_alloc(ctx
, n
);
1598 if (isl_set_foreach_basic_set(set
, &collect_basic_set
, &list
) < 0)
1599 list
= isl_basic_set_list_free(list
);
1605 /* Generate code for the schedule domain "bounds"
1606 * and add the result to "list".
1608 * We mainly detect strides and additional equalities here
1609 * and then pass over control to create_node.
1611 * "bounds" reflects the bounds on the current dimension and possibly
1612 * some extra conditions on outer dimensions.
1613 * It does not, however, include any divs involving the current dimension,
1614 * so it does not capture any stride constraints.
1615 * We therefore need to compute that part of the schedule domain that
1616 * intersects with "bounds" and derive the strides from the result.
1618 static __isl_give isl_ast_graft_list
*add_node(
1619 __isl_take isl_ast_graft_list
*list
, __isl_take isl_union_map
*executed
,
1620 __isl_take isl_basic_set
*bounds
, __isl_take isl_ast_build
*build
)
1622 isl_ast_graft
*graft
;
1623 isl_set
*domain
= NULL
;
1624 isl_union_set
*uset
;
1627 uset
= isl_union_set_from_basic_set(isl_basic_set_copy(bounds
));
1628 executed
= isl_union_map_intersect_domain(executed
, uset
);
1629 empty
= isl_union_map_is_empty(executed
);
1635 uset
= isl_union_map_domain(isl_union_map_copy(executed
));
1636 domain
= isl_set_from_union_set(uset
);
1637 domain
= isl_ast_build_compute_gist(build
, domain
);
1638 empty
= isl_set_is_empty(domain
);
1644 domain
= isl_ast_build_eliminate_inner(build
, domain
);
1645 build
= isl_ast_build_detect_strides(build
, isl_set_copy(domain
));
1647 graft
= create_node(executed
, bounds
, domain
,
1648 isl_ast_build_copy(build
));
1649 list
= isl_ast_graft_list_add(list
, graft
);
1650 isl_ast_build_free(build
);
1653 list
= isl_ast_graft_list_free(list
);
1655 isl_set_free(domain
);
1656 isl_basic_set_free(bounds
);
1657 isl_union_map_free(executed
);
1658 isl_ast_build_free(build
);
1662 /* Does any element of i follow or coincide with any element of j
1663 * at the current depth for equal values of the outer dimensions?
1665 static int domain_follows_at_depth(__isl_keep isl_basic_set
*i
,
1666 __isl_keep isl_basic_set
*j
, void *user
)
1668 int depth
= *(int *) user
;
1669 isl_basic_map
*test
;
1673 test
= isl_basic_map_from_domain_and_range(isl_basic_set_copy(i
),
1674 isl_basic_set_copy(j
));
1675 for (l
= 0; l
< depth
; ++l
)
1676 test
= isl_basic_map_equate(test
, isl_dim_in
, l
,
1678 test
= isl_basic_map_order_ge(test
, isl_dim_in
, depth
,
1679 isl_dim_out
, depth
);
1680 empty
= isl_basic_map_is_empty(test
);
1681 isl_basic_map_free(test
);
1683 return empty
< 0 ? -1 : !empty
;
1686 /* Split up each element of "list" into a part that is related to "bset"
1687 * according to "gt" and a part that is not.
1688 * Return a list that consist of "bset" and all the pieces.
1690 static __isl_give isl_basic_set_list
*add_split_on(
1691 __isl_take isl_basic_set_list
*list
, __isl_take isl_basic_set
*bset
,
1692 __isl_keep isl_basic_map
*gt
)
1695 isl_basic_set_list
*res
;
1698 bset
= isl_basic_set_free(bset
);
1700 gt
= isl_basic_map_copy(gt
);
1701 gt
= isl_basic_map_intersect_domain(gt
, isl_basic_set_copy(bset
));
1702 n
= isl_basic_set_list_n_basic_set(list
);
1703 res
= isl_basic_set_list_from_basic_set(bset
);
1704 for (i
= 0; res
&& i
< n
; ++i
) {
1705 isl_basic_set
*bset
;
1706 isl_set
*set1
, *set2
;
1707 isl_basic_map
*bmap
;
1710 bset
= isl_basic_set_list_get_basic_set(list
, i
);
1711 bmap
= isl_basic_map_copy(gt
);
1712 bmap
= isl_basic_map_intersect_range(bmap
, bset
);
1713 bset
= isl_basic_map_range(bmap
);
1714 empty
= isl_basic_set_is_empty(bset
);
1716 res
= isl_basic_set_list_free(res
);
1718 isl_basic_set_free(bset
);
1719 bset
= isl_basic_set_list_get_basic_set(list
, i
);
1720 res
= isl_basic_set_list_add(res
, bset
);
1724 res
= isl_basic_set_list_add(res
, isl_basic_set_copy(bset
));
1725 set1
= isl_set_from_basic_set(bset
);
1726 bset
= isl_basic_set_list_get_basic_set(list
, i
);
1727 set2
= isl_set_from_basic_set(bset
);
1728 set1
= isl_set_subtract(set2
, set1
);
1729 set1
= isl_set_make_disjoint(set1
);
1731 res
= isl_basic_set_list_concat(res
,
1732 isl_basic_set_list_from_set(set1
));
1734 isl_basic_map_free(gt
);
1735 isl_basic_set_list_free(list
);
1739 static __isl_give isl_ast_graft_list
*generate_sorted_domains(
1740 __isl_keep isl_basic_set_list
*domain_list
,
1741 __isl_keep isl_union_map
*executed
,
1742 __isl_keep isl_ast_build
*build
);
1744 /* Internal data structure for add_nodes.
1746 * "executed" and "build" are extra arguments to be passed to add_node.
1747 * "list" collects the results.
1749 struct isl_add_nodes_data
{
1750 isl_union_map
*executed
;
1751 isl_ast_build
*build
;
1753 isl_ast_graft_list
*list
;
1756 /* Generate code for the schedule domains in "scc"
1757 * and add the results to "list".
1759 * The domains in "scc" form a strongly connected component in the ordering.
1760 * If the number of domains in "scc" is larger than 1, then this means
1761 * that we cannot determine a valid ordering for the domains in the component.
1762 * This should be fairly rare because the individual domains
1763 * have been made disjoint first.
1764 * The problem is that the domains may be integrally disjoint but not
1765 * rationally disjoint. For example, we may have domains
1767 * { [i,i] : 0 <= i <= 1 } and { [i,1-i] : 0 <= i <= 1 }
1769 * These two domains have an empty intersection, but their rational
1770 * relaxations do intersect. It is impossible to order these domains
1771 * in the second dimension because the first should be ordered before
1772 * the second for outer dimension equal to 0, while it should be ordered
1773 * after for outer dimension equal to 1.
1775 * This may happen in particular in case of unrolling since the domain
1776 * of each slice is replaced by its simple hull.
1778 * For each basic set i in "scc" and for each of the following basic sets j,
1779 * we split off that part of the basic set i that shares the outer dimensions
1780 * with j and lies before j in the current dimension.
1781 * We collect all the pieces in a new list that replaces "scc".
1783 * While the elements in "scc" should be disjoint, we double-check
1784 * this property to avoid running into an infinite recursion in case
1785 * they intersect due to some internal error.
1787 static int add_nodes(__isl_take isl_basic_set_list
*scc
, void *user
)
1789 struct isl_add_nodes_data
*data
= user
;
1791 isl_basic_set
*bset
, *first
;
1792 isl_basic_set_list
*list
;
1796 n
= isl_basic_set_list_n_basic_set(scc
);
1797 bset
= isl_basic_set_list_get_basic_set(scc
, 0);
1799 isl_basic_set_list_free(scc
);
1800 data
->list
= add_node(data
->list
,
1801 isl_union_map_copy(data
->executed
), bset
,
1802 isl_ast_build_copy(data
->build
));
1803 return data
->list
? 0 : -1;
1806 depth
= isl_ast_build_get_depth(data
->build
);
1807 space
= isl_basic_set_get_space(bset
);
1808 space
= isl_space_map_from_set(space
);
1809 gt
= isl_basic_map_universe(space
);
1810 for (i
= 0; i
< depth
; ++i
)
1811 gt
= isl_basic_map_equate(gt
, isl_dim_in
, i
, isl_dim_out
, i
);
1812 gt
= isl_basic_map_order_gt(gt
, isl_dim_in
, depth
, isl_dim_out
, depth
);
1814 first
= isl_basic_set_copy(bset
);
1815 list
= isl_basic_set_list_from_basic_set(bset
);
1816 for (i
= 1; i
< n
; ++i
) {
1819 bset
= isl_basic_set_list_get_basic_set(scc
, i
);
1821 disjoint
= isl_basic_set_is_disjoint(bset
, first
);
1823 list
= isl_basic_set_list_free(list
);
1825 isl_die(isl_basic_set_list_get_ctx(scc
),
1827 "basic sets in scc are assumed to be disjoint",
1828 list
= isl_basic_set_list_free(list
));
1830 list
= add_split_on(list
, bset
, gt
);
1832 isl_basic_set_free(first
);
1833 isl_basic_map_free(gt
);
1834 isl_basic_set_list_free(scc
);
1836 data
->list
= isl_ast_graft_list_concat(data
->list
,
1837 generate_sorted_domains(scc
, data
->executed
, data
->build
));
1838 isl_basic_set_list_free(scc
);
1840 return data
->list
? 0 : -1;
1843 /* Sort the domains in "domain_list" according to the execution order
1844 * at the current depth (for equal values of the outer dimensions),
1845 * generate code for each of them, collecting the results in a list.
1846 * If no code is generated (because the intersection of the inverse schedule
1847 * with the domains turns out to be empty), then an empty list is returned.
1849 * The caller is responsible for ensuring that the basic sets in "domain_list"
1850 * are pair-wise disjoint. It can, however, in principle happen that
1851 * two basic sets should be ordered one way for one value of the outer
1852 * dimensions and the other way for some other value of the outer dimensions.
1853 * We therefore play safe and look for strongly connected components.
1854 * The function add_nodes takes care of handling non-trivial components.
1856 static __isl_give isl_ast_graft_list
*generate_sorted_domains(
1857 __isl_keep isl_basic_set_list
*domain_list
,
1858 __isl_keep isl_union_map
*executed
, __isl_keep isl_ast_build
*build
)
1861 struct isl_add_nodes_data data
;
1868 ctx
= isl_basic_set_list_get_ctx(domain_list
);
1869 n
= isl_basic_set_list_n_basic_set(domain_list
);
1870 data
.list
= isl_ast_graft_list_alloc(ctx
, n
);
1874 return add_node(data
.list
, isl_union_map_copy(executed
),
1875 isl_basic_set_list_get_basic_set(domain_list
, 0),
1876 isl_ast_build_copy(build
));
1878 depth
= isl_ast_build_get_depth(build
);
1879 data
.executed
= executed
;
1881 if (isl_basic_set_list_foreach_scc(domain_list
,
1882 &domain_follows_at_depth
, &depth
,
1883 &add_nodes
, &data
) < 0)
1884 data
.list
= isl_ast_graft_list_free(data
.list
);
1889 /* Do i and j share any values for the outer dimensions?
1891 static int shared_outer(__isl_keep isl_basic_set
*i
,
1892 __isl_keep isl_basic_set
*j
, void *user
)
1894 int depth
= *(int *) user
;
1895 isl_basic_map
*test
;
1899 test
= isl_basic_map_from_domain_and_range(isl_basic_set_copy(i
),
1900 isl_basic_set_copy(j
));
1901 for (l
= 0; l
< depth
; ++l
)
1902 test
= isl_basic_map_equate(test
, isl_dim_in
, l
,
1904 empty
= isl_basic_map_is_empty(test
);
1905 isl_basic_map_free(test
);
1907 return empty
< 0 ? -1 : !empty
;
1910 /* Internal data structure for generate_sorted_domains_wrap.
1912 * "n" is the total number of basic sets
1913 * "executed" and "build" are extra arguments to be passed
1914 * to generate_sorted_domains.
1916 * "single" is set to 1 by generate_sorted_domains_wrap if there
1917 * is only a single component.
1918 * "list" collects the results.
1920 struct isl_ast_generate_parallel_domains_data
{
1922 isl_union_map
*executed
;
1923 isl_ast_build
*build
;
1926 isl_ast_graft_list
*list
;
1929 /* Call generate_sorted_domains on "scc", fuse the result into a list
1930 * with either zero or one graft and collect the these single element
1931 * lists into data->list.
1933 * If there is only one component, i.e., if the number of basic sets
1934 * in the current component is equal to the total number of basic sets,
1935 * then data->single is set to 1 and the result of generate_sorted_domains
1938 static int generate_sorted_domains_wrap(__isl_take isl_basic_set_list
*scc
,
1941 struct isl_ast_generate_parallel_domains_data
*data
= user
;
1942 isl_ast_graft_list
*list
;
1944 list
= generate_sorted_domains(scc
, data
->executed
, data
->build
);
1945 data
->single
= isl_basic_set_list_n_basic_set(scc
) == data
->n
;
1947 list
= isl_ast_graft_list_fuse(list
, data
->build
);
1951 data
->list
= isl_ast_graft_list_concat(data
->list
, list
);
1953 isl_basic_set_list_free(scc
);
1960 /* Look for any (weakly connected) components in the "domain_list"
1961 * of domains that share some values of the outer dimensions.
1962 * That is, domains in different components do not share any values
1963 * of the outer dimensions. This means that these components
1964 * can be freely reordered.
1965 * Within each of the components, we sort the domains according
1966 * to the execution order at the current depth.
1968 * If there is more than one component, then generate_sorted_domains_wrap
1969 * fuses the result of each call to generate_sorted_domains
1970 * into a list with either zero or one graft and collects these (at most)
1971 * single element lists into a bigger list. This means that the elements of the
1972 * final list can be freely reordered. In particular, we sort them
1973 * according to an arbitrary but fixed ordering to ease merging of
1974 * graft lists from different components.
1976 static __isl_give isl_ast_graft_list
*generate_parallel_domains(
1977 __isl_keep isl_basic_set_list
*domain_list
,
1978 __isl_keep isl_union_map
*executed
, __isl_keep isl_ast_build
*build
)
1981 struct isl_ast_generate_parallel_domains_data data
;
1986 data
.n
= isl_basic_set_list_n_basic_set(domain_list
);
1988 return generate_sorted_domains(domain_list
, executed
, build
);
1990 depth
= isl_ast_build_get_depth(build
);
1992 data
.executed
= executed
;
1995 if (isl_basic_set_list_foreach_scc(domain_list
, &shared_outer
, &depth
,
1996 &generate_sorted_domains_wrap
,
1998 data
.list
= isl_ast_graft_list_free(data
.list
);
2001 data
.list
= isl_ast_graft_list_sort_guard(data
.list
);
2006 /* Internal data for separate_domain.
2008 * "explicit" is set if we only want to use explicit bounds.
2010 * "domain" collects the separated domains.
2012 struct isl_separate_domain_data
{
2013 isl_ast_build
*build
;
2018 /* Extract implicit bounds on the current dimension for the executed "map".
2020 * The domain of "map" may involve inner dimensions, so we
2021 * need to eliminate them.
2023 static __isl_give isl_set
*implicit_bounds(__isl_take isl_map
*map
,
2024 __isl_keep isl_ast_build
*build
)
2028 domain
= isl_map_domain(map
);
2029 domain
= isl_ast_build_eliminate(build
, domain
);
2034 /* Extract explicit bounds on the current dimension for the executed "map".
2036 * Rather than eliminating the inner dimensions as in implicit_bounds,
2037 * we simply drop any constraints involving those inner dimensions.
2038 * The idea is that most bounds that are implied by constraints on the
2039 * inner dimensions will be enforced by for loops and not by explicit guards.
2040 * There is then no need to separate along those bounds.
2042 static __isl_give isl_set
*explicit_bounds(__isl_take isl_map
*map
,
2043 __isl_keep isl_ast_build
*build
)
2048 dim
= isl_map_dim(map
, isl_dim_out
);
2049 map
= isl_map_drop_constraints_involving_dims(map
, isl_dim_out
, 0, dim
);
2051 domain
= isl_map_domain(map
);
2052 depth
= isl_ast_build_get_depth(build
);
2053 dim
= isl_set_dim(domain
, isl_dim_set
);
2054 domain
= isl_set_detect_equalities(domain
);
2055 domain
= isl_set_drop_constraints_involving_dims(domain
,
2056 isl_dim_set
, depth
+ 1, dim
- (depth
+ 1));
2057 domain
= isl_set_remove_divs_involving_dims(domain
,
2058 isl_dim_set
, depth
, 1);
2059 domain
= isl_set_remove_unknown_divs(domain
);
2064 /* Split data->domain into pieces that intersect with the range of "map"
2065 * and pieces that do not intersect with the range of "map"
2066 * and then add that part of the range of "map" that does not intersect
2067 * with data->domain.
2069 static int separate_domain(__isl_take isl_map
*map
, void *user
)
2071 struct isl_separate_domain_data
*data
= user
;
2076 domain
= explicit_bounds(map
, data
->build
);
2078 domain
= implicit_bounds(map
, data
->build
);
2080 domain
= isl_set_coalesce(domain
);
2081 domain
= isl_set_make_disjoint(domain
);
2082 d1
= isl_set_subtract(isl_set_copy(domain
), isl_set_copy(data
->domain
));
2083 d2
= isl_set_subtract(isl_set_copy(data
->domain
), isl_set_copy(domain
));
2084 data
->domain
= isl_set_intersect(data
->domain
, domain
);
2085 data
->domain
= isl_set_union(data
->domain
, d1
);
2086 data
->domain
= isl_set_union(data
->domain
, d2
);
2091 /* Separate the schedule domains of "executed".
2093 * That is, break up the domain of "executed" into basic sets,
2094 * such that for each basic set S, every element in S is associated with
2095 * the same domain spaces.
2097 * "space" is the (single) domain space of "executed".
2099 static __isl_give isl_set
*separate_schedule_domains(
2100 __isl_take isl_space
*space
, __isl_take isl_union_map
*executed
,
2101 __isl_keep isl_ast_build
*build
)
2103 struct isl_separate_domain_data data
= { build
};
2106 ctx
= isl_ast_build_get_ctx(build
);
2107 data
.explicit = isl_options_get_ast_build_separation_bounds(ctx
) ==
2108 ISL_AST_BUILD_SEPARATION_BOUNDS_EXPLICIT
;
2109 data
.domain
= isl_set_empty(space
);
2110 if (isl_union_map_foreach_map(executed
, &separate_domain
, &data
) < 0)
2111 data
.domain
= isl_set_free(data
.domain
);
2113 isl_union_map_free(executed
);
2117 /* Temporary data used during the search for a lower bound for unrolling.
2119 * "domain" is the original set for which to find a lower bound
2120 * "depth" is the dimension for which to find a lower boudn
2122 * "lower" is the best lower bound found so far. It is NULL if we have not
2124 * "n" is the corresponding size. If lower is NULL, then the value of n
2127 struct isl_find_unroll_data
{
2135 /* Check if we can use "c" as a lower bound and if it is better than
2136 * any previously found lower bound.
2138 * If "c" does not involve the dimension at the current depth,
2139 * then we cannot use it.
2140 * Otherwise, let "c" be of the form
2144 * We compute the maximal value of
2146 * -ceil(f(j)/a)) + i + 1
2148 * over the domain. If there is such a value "n", then we know
2150 * -ceil(f(j)/a)) + i + 1 <= n
2154 * i < ceil(f(j)/a)) + n
2156 * meaning that we can use ceil(f(j)/a)) as a lower bound for unrolling.
2157 * We just need to check if we have found any lower bound before and
2158 * if the new lower bound is better (smaller n) than the previously found
2161 static int update_unrolling_lower_bound(struct isl_find_unroll_data
*data
,
2162 __isl_keep isl_constraint
*c
)
2164 isl_aff
*aff
, *lower
;
2167 if (!isl_constraint_is_lower_bound(c
, isl_dim_set
, data
->depth
))
2170 lower
= isl_constraint_get_bound(c
, isl_dim_set
, data
->depth
);
2171 lower
= isl_aff_ceil(lower
);
2172 aff
= isl_aff_copy(lower
);
2173 aff
= isl_aff_neg(aff
);
2174 aff
= isl_aff_add_coefficient_si(aff
, isl_dim_in
, data
->depth
, 1);
2175 aff
= isl_aff_add_constant_si(aff
, 1);
2176 max
= isl_set_max_val(data
->domain
, aff
);
2181 if (isl_val_is_infty(max
)) {
2183 isl_aff_free(lower
);
2187 if (isl_val_cmp_si(max
, INT_MAX
) <= 0 &&
2188 (!data
->lower
|| isl_val_cmp_si(max
, *data
->n
) < 0)) {
2189 isl_aff_free(data
->lower
);
2190 data
->lower
= lower
;
2191 *data
->n
= isl_val_get_num_si(max
);
2193 isl_aff_free(lower
);
2198 isl_aff_free(lower
);
2202 /* Check if we can use "c" as a lower bound and if it is better than
2203 * any previously found lower bound.
2205 static int constraint_find_unroll(__isl_take isl_constraint
*c
, void *user
)
2207 struct isl_find_unroll_data
*data
;
2210 data
= (struct isl_find_unroll_data
*) user
;
2211 r
= update_unrolling_lower_bound(data
, c
);
2212 isl_constraint_free(c
);
2217 /* Look for a lower bound l(i) on the dimension at "depth"
2218 * and a size n such that "domain" is a subset of
2220 * { [i] : l(i) <= i_d < l(i) + n }
2222 * where d is "depth" and l(i) depends only on earlier dimensions.
2223 * Furthermore, try and find a lower bound such that n is as small as possible.
2224 * In particular, "n" needs to be finite.
2226 * Inner dimensions have been eliminated from "domain" by the caller.
2228 * We first construct a collection of lower bounds on the input set
2229 * by computing its simple hull. We then iterate through them,
2230 * discarding those that we cannot use (either because they do not
2231 * involve the dimension at "depth" or because they have no corresponding
2232 * upper bound, meaning that "n" would be unbounded) and pick out the
2233 * best from the remaining ones.
2235 * If we cannot find a suitable lower bound, then we consider that
2238 static __isl_give isl_aff
*find_unroll_lower_bound(__isl_keep isl_set
*domain
,
2241 struct isl_find_unroll_data data
= { domain
, depth
, NULL
, n
};
2242 isl_basic_set
*hull
;
2244 hull
= isl_set_simple_hull(isl_set_copy(domain
));
2246 if (isl_basic_set_foreach_constraint(hull
,
2247 &constraint_find_unroll
, &data
) < 0)
2250 isl_basic_set_free(hull
);
2253 isl_die(isl_set_get_ctx(domain
), isl_error_invalid
,
2254 "cannot find lower bound for unrolling", return NULL
);
2258 isl_basic_set_free(hull
);
2259 return isl_aff_free(data
.lower
);
2262 /* Return the constraint
2264 * i_"depth" = aff + offset
2266 static __isl_give isl_constraint
*at_offset(int depth
, __isl_keep isl_aff
*aff
,
2269 aff
= isl_aff_copy(aff
);
2270 aff
= isl_aff_add_coefficient_si(aff
, isl_dim_in
, depth
, -1);
2271 aff
= isl_aff_add_constant_si(aff
, offset
);
2272 return isl_equality_from_aff(aff
);
2275 /* Return a list of basic sets, one for each value of the current dimension
2277 * The divs that involve the current dimension have not been projected out
2280 * Since we are going to be iterating over the individual values,
2281 * we first check if there are any strides on the current dimension.
2282 * If there is, we rewrite the current dimension i as
2284 * i = stride i' + offset
2286 * and then iterate over individual values of i' instead.
2288 * We then look for a lower bound on i' and a size such that the domain
2291 * { [j,i'] : l(j) <= i' < l(j) + n }
2293 * and then take slices of the domain at values of i'
2294 * between l(j) and l(j) + n - 1.
2296 * We compute the unshifted simple hull of each slice to ensure that
2297 * we have a single basic set per offset. The slicing constraint
2298 * may get simplified away before the unshifted simple hull is taken
2299 * and may therefore in some rare cases disappear from the result.
2300 * We therefore explicitly add the constraint back after computing
2301 * the unshifted simple hull to ensure that the basic sets
2302 * remain disjoint. The constraints that are dropped by taking the hull
2303 * will be taken into account at the next level, as in the case of the
2306 * Finally, we map i' back to i and add each basic set to the list.
2308 static __isl_give isl_basic_set_list
*do_unroll(__isl_take isl_set
*domain
,
2309 __isl_keep isl_ast_build
*build
)
2315 isl_basic_set_list
*list
;
2316 isl_multi_aff
*expansion
;
2317 isl_basic_map
*bmap
;
2322 ctx
= isl_set_get_ctx(domain
);
2323 depth
= isl_ast_build_get_depth(build
);
2324 build
= isl_ast_build_copy(build
);
2325 domain
= isl_ast_build_eliminate_inner(build
, domain
);
2326 build
= isl_ast_build_detect_strides(build
, isl_set_copy(domain
));
2327 expansion
= isl_ast_build_get_stride_expansion(build
);
2329 domain
= isl_set_preimage_multi_aff(domain
,
2330 isl_multi_aff_copy(expansion
));
2331 domain
= isl_ast_build_eliminate_divs(build
, domain
);
2333 isl_ast_build_free(build
);
2335 list
= isl_basic_set_list_alloc(ctx
, 0);
2337 lower
= find_unroll_lower_bound(domain
, depth
, &n
);
2339 list
= isl_basic_set_list_free(list
);
2341 bmap
= isl_basic_map_from_multi_aff(expansion
);
2343 for (i
= 0; list
&& i
< n
; ++i
) {
2345 isl_basic_set
*bset
;
2346 isl_constraint
*slice
;
2348 slice
= at_offset(depth
, lower
, i
);
2349 set
= isl_set_copy(domain
);
2350 set
= isl_set_add_constraint(set
, isl_constraint_copy(slice
));
2351 bset
= isl_set_unshifted_simple_hull(set
);
2352 bset
= isl_basic_set_add_constraint(bset
, slice
);
2353 bset
= isl_basic_set_apply(bset
, isl_basic_map_copy(bmap
));
2354 list
= isl_basic_set_list_add(list
, bset
);
2357 isl_aff_free(lower
);
2358 isl_set_free(domain
);
2359 isl_basic_map_free(bmap
);
2364 /* Data structure for storing the results and the intermediate objects
2365 * of compute_domains.
2367 * "list" is the main result of the function and contains a list
2368 * of disjoint basic sets for which code should be generated.
2370 * "executed" and "build" are inputs to compute_domains.
2371 * "schedule_domain" is the domain of "executed".
2373 * "option" constains the domains at the current depth that should by
2374 * atomic, separated or unrolled. These domains are as specified by
2375 * the user, except that inner dimensions have been eliminated and
2376 * that they have been made pair-wise disjoint.
2378 * "sep_class" contains the user-specified split into separation classes
2379 * specialized to the current depth.
2380 * "done" contains the union of the separation domains that have already
2382 * "atomic" contains the domain that has effectively been made atomic.
2383 * This domain may be larger than the intersection of option[atomic]
2384 * and the schedule domain.
2386 struct isl_codegen_domains
{
2387 isl_basic_set_list
*list
;
2389 isl_union_map
*executed
;
2390 isl_ast_build
*build
;
2391 isl_set
*schedule_domain
;
2400 /* Add domains to domains->list for each individual value of the current
2401 * dimension, for that part of the schedule domain that lies in the
2402 * intersection of the option domain and the class domain.
2404 * "domain" is the intersection of the class domain and the schedule domain.
2405 * The divs that involve the current dimension have not been projected out
2408 * We first break up the unroll option domain into individual pieces
2409 * and then handle each of them separately. The unroll option domain
2410 * has been made disjoint in compute_domains_init_options,
2412 * Note that we actively want to combine different pieces of the
2413 * schedule domain that have the same value at the current dimension.
2414 * We therefore need to break up the unroll option domain before
2415 * intersecting with class and schedule domain, hoping that the
2416 * unroll option domain specified by the user is relatively simple.
2418 static int compute_unroll_domains(struct isl_codegen_domains
*domains
,
2419 __isl_keep isl_set
*domain
)
2421 isl_set
*unroll_domain
;
2422 isl_basic_set_list
*unroll_list
;
2426 empty
= isl_set_is_empty(domains
->option
[unroll
]);
2432 unroll_domain
= isl_set_copy(domains
->option
[unroll
]);
2433 unroll_list
= isl_basic_set_list_from_set(unroll_domain
);
2435 n
= isl_basic_set_list_n_basic_set(unroll_list
);
2436 for (i
= 0; i
< n
; ++i
) {
2437 isl_basic_set
*bset
;
2438 isl_basic_set_list
*list
;
2440 bset
= isl_basic_set_list_get_basic_set(unroll_list
, i
);
2441 unroll_domain
= isl_set_from_basic_set(bset
);
2442 unroll_domain
= isl_set_intersect(unroll_domain
,
2443 isl_set_copy(domain
));
2445 empty
= isl_set_is_empty(unroll_domain
);
2446 if (empty
>= 0 && empty
) {
2447 isl_set_free(unroll_domain
);
2451 list
= do_unroll(unroll_domain
, domains
->build
);
2452 domains
->list
= isl_basic_set_list_concat(domains
->list
, list
);
2455 isl_basic_set_list_free(unroll_list
);
2460 /* Try and construct a single basic set that includes the intersection of
2461 * the schedule domain, the atomic option domain and the class domain.
2462 * Add the resulting basic set(s) to domains->list and save a copy
2463 * in domains->atomic for use in compute_partial_domains.
2465 * We construct a single domain rather than trying to combine
2466 * the schedule domains of individual domains because we are working
2467 * within a single component so that non-overlapping schedule domains
2468 * should already have been separated.
2469 * We do however need to make sure that this single domains is a subset
2470 * of the class domain so that it would not intersect with any other
2471 * class domains. This means that we may end up splitting up the atomic
2472 * domain in case separation classes are being used.
2474 * "domain" is the intersection of the schedule domain and the class domain,
2475 * with inner dimensions projected out.
2477 static int compute_atomic_domain(struct isl_codegen_domains
*domains
,
2478 __isl_keep isl_set
*class_domain
)
2480 isl_basic_set
*bset
;
2481 isl_basic_set_list
*list
;
2485 domain
= isl_set_copy(domains
->option
[atomic
]);
2486 domain
= isl_set_intersect(domain
, isl_set_copy(class_domain
));
2487 domain
= isl_set_intersect(domain
,
2488 isl_set_copy(domains
->schedule_domain
));
2489 empty
= isl_set_is_empty(domain
);
2490 if (empty
< 0 || empty
) {
2491 domains
->atomic
= domain
;
2492 return empty
< 0 ? -1 : 0;
2495 domain
= isl_ast_build_eliminate(domains
->build
, domain
);
2496 domain
= isl_set_coalesce(domain
);
2497 bset
= isl_set_unshifted_simple_hull(domain
);
2498 domain
= isl_set_from_basic_set(bset
);
2499 domains
->atomic
= isl_set_copy(domain
);
2500 domain
= isl_set_intersect(domain
, isl_set_copy(class_domain
));
2501 domain
= isl_set_make_disjoint(domain
);
2502 list
= isl_basic_set_list_from_set(domain
);
2503 domains
->list
= isl_basic_set_list_concat(domains
->list
, list
);
2508 /* Split up the schedule domain into uniform basic sets,
2509 * in the sense that each element in a basic set is associated to
2510 * elements of the same domains, and add the result to domains->list.
2511 * Do this for that part of the schedule domain that lies in the
2512 * intersection of "class_domain" and the separate option domain.
2514 * "class_domain" may or may not include the constraints
2515 * of the schedule domain, but this does not make a difference
2516 * since we are going to intersect it with the domain of the inverse schedule.
2517 * If it includes schedule domain constraints, then they may involve
2518 * inner dimensions, but we will eliminate them in separation_domain.
2520 static int compute_separate_domain(struct isl_codegen_domains
*domains
,
2521 __isl_keep isl_set
*class_domain
)
2525 isl_union_map
*executed
;
2526 isl_basic_set_list
*list
;
2529 domain
= isl_set_copy(domains
->option
[separate
]);
2530 domain
= isl_set_intersect(domain
, isl_set_copy(class_domain
));
2531 executed
= isl_union_map_copy(domains
->executed
);
2532 executed
= isl_union_map_intersect_domain(executed
,
2533 isl_union_set_from_set(domain
));
2534 empty
= isl_union_map_is_empty(executed
);
2535 if (empty
< 0 || empty
) {
2536 isl_union_map_free(executed
);
2537 return empty
< 0 ? -1 : 0;
2540 space
= isl_set_get_space(class_domain
);
2541 domain
= separate_schedule_domains(space
, executed
, domains
->build
);
2543 list
= isl_basic_set_list_from_set(domain
);
2544 domains
->list
= isl_basic_set_list_concat(domains
->list
, list
);
2549 /* Split up the domain at the current depth into disjoint
2550 * basic sets for which code should be generated separately
2551 * for the given separation class domain.
2553 * If any separation classes have been defined, then "class_domain"
2554 * is the domain of the current class and does not refer to inner dimensions.
2555 * Otherwise, "class_domain" is the universe domain.
2557 * We first make sure that the class domain is disjoint from
2558 * previously considered class domains.
2560 * The separate domains can be computed directly from the "class_domain".
2562 * The unroll, atomic and remainder domains need the constraints
2563 * from the schedule domain.
2565 * For unrolling, the actual schedule domain is needed (with divs that
2566 * may refer to the current dimension) so that stride detection can be
2569 * For atomic and remainder domains, inner dimensions and divs involving
2570 * the current dimensions should be eliminated.
2571 * In case we are working within a separation class, we need to intersect
2572 * the result with the current "class_domain" to ensure that the domains
2573 * are disjoint from those generated from other class domains.
2575 * The domain that has been made atomic may be larger than specified
2576 * by the user since it needs to be representable as a single basic set.
2577 * This possibly larger domain is stored in domains->atomic by
2578 * compute_atomic_domain. It is computed first so that the extended domain
2579 * would not overlap with any domains computed before.
2581 * If anything is left after handling separate, unroll and atomic,
2582 * we split it up into basic sets and append the basic sets to domains->list.
2584 static int compute_partial_domains(struct isl_codegen_domains
*domains
,
2585 __isl_take isl_set
*class_domain
)
2587 isl_basic_set_list
*list
;
2590 class_domain
= isl_set_subtract(class_domain
,
2591 isl_set_copy(domains
->done
));
2592 domains
->done
= isl_set_union(domains
->done
,
2593 isl_set_copy(class_domain
));
2595 domain
= isl_set_copy(class_domain
);
2597 if (compute_atomic_domain(domains
, class_domain
) < 0)
2598 domain
= isl_set_free(domain
);
2599 domain
= isl_set_subtract(domain
, domains
->atomic
);
2601 if (compute_separate_domain(domains
, domain
) < 0)
2603 domain
= isl_set_subtract(domain
,
2604 isl_set_copy(domains
->option
[separate
]));
2606 domain
= isl_set_intersect(domain
,
2607 isl_set_copy(domains
->schedule_domain
));
2609 if (compute_unroll_domains(domains
, domain
) < 0)
2611 domain
= isl_set_subtract(domain
,
2612 isl_set_copy(domains
->option
[unroll
]));
2614 domain
= isl_ast_build_eliminate(domains
->build
, domain
);
2615 domain
= isl_set_intersect(domain
, isl_set_copy(class_domain
));
2617 domain
= isl_set_coalesce(domain
);
2618 domain
= isl_set_make_disjoint(domain
);
2620 list
= isl_basic_set_list_from_set(domain
);
2621 domains
->list
= isl_basic_set_list_concat(domains
->list
, list
);
2623 isl_set_free(class_domain
);
2627 isl_set_free(domain
);
2628 isl_set_free(class_domain
);
2632 /* Split up the domain at the current depth into disjoint
2633 * basic sets for which code should be generated separately
2634 * for the separation class identified by "pnt".
2636 * We extract the corresponding class domain from domains->sep_class,
2637 * eliminate inner dimensions and pass control to compute_partial_domains.
2639 static int compute_class_domains(__isl_take isl_point
*pnt
, void *user
)
2641 struct isl_codegen_domains
*domains
= user
;
2646 class_set
= isl_set_from_point(pnt
);
2647 domain
= isl_map_domain(isl_map_intersect_range(
2648 isl_map_copy(domains
->sep_class
), class_set
));
2649 domain
= isl_ast_build_compute_gist(domains
->build
, domain
);
2650 domain
= isl_ast_build_eliminate(domains
->build
, domain
);
2652 disjoint
= isl_set_plain_is_disjoint(domain
, domains
->schedule_domain
);
2656 isl_set_free(domain
);
2660 return compute_partial_domains(domains
, domain
);
2663 /* Extract the domains at the current depth that should be atomic,
2664 * separated or unrolled and store them in option.
2666 * The domains specified by the user might overlap, so we make
2667 * them disjoint by subtracting earlier domains from later domains.
2669 static void compute_domains_init_options(isl_set
*option
[3],
2670 __isl_keep isl_ast_build
*build
)
2672 enum isl_ast_build_domain_type type
, type2
;
2674 for (type
= atomic
; type
<= separate
; ++type
) {
2675 option
[type
] = isl_ast_build_get_option_domain(build
, type
);
2676 for (type2
= atomic
; type2
< type
; ++type2
)
2677 option
[type
] = isl_set_subtract(option
[type
],
2678 isl_set_copy(option
[type2
]));
2681 option
[unroll
] = isl_set_coalesce(option
[unroll
]);
2682 option
[unroll
] = isl_set_make_disjoint(option
[unroll
]);
2685 /* Split up the domain at the current depth into disjoint
2686 * basic sets for which code should be generated separately,
2687 * based on the user-specified options.
2688 * Return the list of disjoint basic sets.
2690 * There are three kinds of domains that we need to keep track of.
2691 * - the "schedule domain" is the domain of "executed"
2692 * - the "class domain" is the domain corresponding to the currrent
2694 * - the "option domain" is the domain corresponding to one of the options
2695 * atomic, unroll or separate
2697 * We first consider the individial values of the separation classes
2698 * and split up the domain for each of them separately.
2699 * Finally, we consider the remainder. If no separation classes were
2700 * specified, then we call compute_partial_domains with the universe
2701 * "class_domain". Otherwise, we take the "schedule_domain" as "class_domain",
2702 * with inner dimensions removed. We do this because we want to
2703 * avoid computing the complement of the class domains (i.e., the difference
2704 * between the universe and domains->done).
2706 static __isl_give isl_basic_set_list
*compute_domains(
2707 __isl_keep isl_union_map
*executed
, __isl_keep isl_ast_build
*build
)
2709 struct isl_codegen_domains domains
;
2712 isl_union_set
*schedule_domain
;
2716 enum isl_ast_build_domain_type type
;
2722 ctx
= isl_union_map_get_ctx(executed
);
2723 domains
.list
= isl_basic_set_list_alloc(ctx
, 0);
2725 schedule_domain
= isl_union_map_domain(isl_union_map_copy(executed
));
2726 domain
= isl_set_from_union_set(schedule_domain
);
2728 compute_domains_init_options(domains
.option
, build
);
2730 domains
.sep_class
= isl_ast_build_get_separation_class(build
);
2731 classes
= isl_map_range(isl_map_copy(domains
.sep_class
));
2732 n_param
= isl_set_dim(classes
, isl_dim_param
);
2733 classes
= isl_set_project_out(classes
, isl_dim_param
, 0, n_param
);
2735 space
= isl_set_get_space(domain
);
2736 domains
.build
= build
;
2737 domains
.schedule_domain
= isl_set_copy(domain
);
2738 domains
.executed
= executed
;
2739 domains
.done
= isl_set_empty(space
);
2741 if (isl_set_foreach_point(classes
, &compute_class_domains
, &domains
) < 0)
2742 domains
.list
= isl_basic_set_list_free(domains
.list
);
2743 isl_set_free(classes
);
2745 empty
= isl_set_is_empty(domains
.done
);
2747 domains
.list
= isl_basic_set_list_free(domains
.list
);
2748 domain
= isl_set_free(domain
);
2750 isl_set_free(domain
);
2751 domain
= isl_set_universe(isl_set_get_space(domains
.done
));
2753 domain
= isl_ast_build_eliminate(build
, domain
);
2755 if (compute_partial_domains(&domains
, domain
) < 0)
2756 domains
.list
= isl_basic_set_list_free(domains
.list
);
2758 isl_set_free(domains
.schedule_domain
);
2759 isl_set_free(domains
.done
);
2760 isl_map_free(domains
.sep_class
);
2761 for (type
= atomic
; type
<= separate
; ++type
)
2762 isl_set_free(domains
.option
[type
]);
2764 return domains
.list
;
2767 /* Generate code for a single component, after shifting (if any)
2770 * We first split up the domain at the current depth into disjoint
2771 * basic sets based on the user-specified options.
2772 * Then we generated code for each of them and concatenate the results.
2774 static __isl_give isl_ast_graft_list
*generate_shifted_component(
2775 __isl_take isl_union_map
*executed
, __isl_take isl_ast_build
*build
)
2777 isl_basic_set_list
*domain_list
;
2778 isl_ast_graft_list
*list
= NULL
;
2780 domain_list
= compute_domains(executed
, build
);
2781 list
= generate_parallel_domains(domain_list
, executed
, build
);
2783 isl_basic_set_list_free(domain_list
);
2784 isl_union_map_free(executed
);
2785 isl_ast_build_free(build
);
2790 struct isl_set_map_pair
{
2795 /* Given an array "domain" of isl_set_map_pairs and an array "order"
2796 * of indices into the "domain" array,
2797 * return the union of the "map" fields of the elements
2798 * indexed by the first "n" elements of "order".
2800 static __isl_give isl_union_map
*construct_component_executed(
2801 struct isl_set_map_pair
*domain
, int *order
, int n
)
2805 isl_union_map
*executed
;
2807 map
= isl_map_copy(domain
[order
[0]].map
);
2808 executed
= isl_union_map_from_map(map
);
2809 for (i
= 1; i
< n
; ++i
) {
2810 map
= isl_map_copy(domain
[order
[i
]].map
);
2811 executed
= isl_union_map_add_map(executed
, map
);
2817 /* Generate code for a single component, after shifting (if any)
2820 * The component inverse schedule is specified as the "map" fields
2821 * of the elements of "domain" indexed by the first "n" elements of "order".
2823 static __isl_give isl_ast_graft_list
*generate_shifted_component_from_list(
2824 struct isl_set_map_pair
*domain
, int *order
, int n
,
2825 __isl_take isl_ast_build
*build
)
2827 isl_union_map
*executed
;
2829 executed
= construct_component_executed(domain
, order
, n
);
2830 return generate_shifted_component(executed
, build
);
2833 /* Does set dimension "pos" of "set" have an obviously fixed value?
2835 static int dim_is_fixed(__isl_keep isl_set
*set
, int pos
)
2840 v
= isl_set_plain_get_val_if_fixed(set
, isl_dim_set
, pos
);
2843 fixed
= !isl_val_is_nan(v
);
2849 /* Given an array "domain" of isl_set_map_pairs and an array "order"
2850 * of indices into the "domain" array,
2851 * do all (except for at most one) of the "set" field of the elements
2852 * indexed by the first "n" elements of "order" have a fixed value
2853 * at position "depth"?
2855 static int at_most_one_non_fixed(struct isl_set_map_pair
*domain
,
2856 int *order
, int n
, int depth
)
2861 for (i
= 0; i
< n
; ++i
) {
2864 f
= dim_is_fixed(domain
[order
[i
]].set
, depth
);
2877 /* Given an array "domain" of isl_set_map_pairs and an array "order"
2878 * of indices into the "domain" array,
2879 * eliminate the inner dimensions from the "set" field of the elements
2880 * indexed by the first "n" elements of "order", provided the current
2881 * dimension does not have a fixed value.
2883 * Return the index of the first element in "order" with a corresponding
2884 * "set" field that does not have an (obviously) fixed value.
2886 static int eliminate_non_fixed(struct isl_set_map_pair
*domain
,
2887 int *order
, int n
, int depth
, __isl_keep isl_ast_build
*build
)
2892 for (i
= n
- 1; i
>= 0; --i
) {
2894 f
= dim_is_fixed(domain
[order
[i
]].set
, depth
);
2899 domain
[order
[i
]].set
= isl_ast_build_eliminate_inner(build
,
2900 domain
[order
[i
]].set
);
2907 /* Given an array "domain" of isl_set_map_pairs and an array "order"
2908 * of indices into the "domain" array,
2909 * find the element of "domain" (amongst those indexed by the first "n"
2910 * elements of "order") with the "set" field that has the smallest
2911 * value for the current iterator.
2913 * Note that the domain with the smallest value may depend on the parameters
2914 * and/or outer loop dimension. Since the result of this function is only
2915 * used as heuristic, we only make a reasonable attempt at finding the best
2916 * domain, one that should work in case a single domain provides the smallest
2917 * value for the current dimension over all values of the parameters
2918 * and outer dimensions.
2920 * In particular, we compute the smallest value of the first domain
2921 * and replace it by that of any later domain if that later domain
2922 * has a smallest value that is smaller for at least some value
2923 * of the parameters and outer dimensions.
2925 static int first_offset(struct isl_set_map_pair
*domain
, int *order
, int n
,
2926 __isl_keep isl_ast_build
*build
)
2932 min_first
= isl_ast_build_map_to_iterator(build
,
2933 isl_set_copy(domain
[order
[0]].set
));
2934 min_first
= isl_map_lexmin(min_first
);
2936 for (i
= 1; i
< n
; ++i
) {
2937 isl_map
*min
, *test
;
2940 min
= isl_ast_build_map_to_iterator(build
,
2941 isl_set_copy(domain
[order
[i
]].set
));
2942 min
= isl_map_lexmin(min
);
2943 test
= isl_map_copy(min
);
2944 test
= isl_map_apply_domain(isl_map_copy(min_first
), test
);
2945 test
= isl_map_order_lt(test
, isl_dim_in
, 0, isl_dim_out
, 0);
2946 empty
= isl_map_is_empty(test
);
2948 if (empty
>= 0 && !empty
) {
2949 isl_map_free(min_first
);
2959 isl_map_free(min_first
);
2961 return i
< n
? -1 : first
;
2964 /* Construct a shifted inverse schedule based on the original inverse schedule,
2965 * the stride and the offset.
2967 * The original inverse schedule is specified as the "map" fields
2968 * of the elements of "domain" indexed by the first "n" elements of "order".
2970 * "stride" and "offset" are such that the difference
2971 * between the values of the current dimension of domain "i"
2972 * and the values of the current dimension for some reference domain are
2975 * stride * integer + offset[i]
2977 * Moreover, 0 <= offset[i] < stride.
2979 * For each domain, we create a map
2981 * { [..., j, ...] -> [..., j - offset[i], offset[i], ....] }
2983 * where j refers to the current dimension and the other dimensions are
2984 * unchanged, and apply this map to the original schedule domain.
2986 * For example, for the original schedule
2988 * { A[i] -> [2i]: 0 <= i < 10; B[i] -> [2i+1] : 0 <= i < 10 }
2990 * and assuming the offset is 0 for the A domain and 1 for the B domain,
2991 * we apply the mapping
2995 * to the schedule of the "A" domain and the mapping
2997 * { [j - 1] -> [j, 1] }
2999 * to the schedule of the "B" domain.
3002 * Note that after the transformation, the differences between pairs
3003 * of values of the current dimension over all domains are multiples
3004 * of stride and that we have therefore exposed the stride.
3007 * To see that the mapping preserves the lexicographic order,
3008 * first note that each of the individual maps above preserves the order.
3009 * If the value of the current iterator is j1 in one domain and j2 in another,
3010 * then if j1 = j2, we know that the same map is applied to both domains
3011 * and the order is preserved.
3012 * Otherwise, let us assume, without loss of generality, that j1 < j2.
3013 * If c1 >= c2 (with c1 and c2 the corresponding offsets), then
3017 * and the order is preserved.
3018 * If c1 < c2, then we know
3024 * j2 - j1 = n * s + r
3026 * with n >= 0 and 0 <= r < s.
3027 * In other words, r = c2 - c1.
3038 * (j1 - c1, c1) << (j2 - c2, c2)
3040 * with "<<" the lexicographic order, proving that the order is preserved
3043 static __isl_give isl_union_map
*contruct_shifted_executed(
3044 struct isl_set_map_pair
*domain
, int *order
, int n
,
3045 __isl_keep isl_val
*stride
, __isl_keep isl_multi_val
*offset
,
3046 __isl_take isl_ast_build
*build
)
3049 isl_union_map
*executed
;
3055 depth
= isl_ast_build_get_depth(build
);
3056 space
= isl_ast_build_get_space(build
, 1);
3057 executed
= isl_union_map_empty(isl_space_copy(space
));
3058 space
= isl_space_map_from_set(space
);
3059 map
= isl_map_identity(isl_space_copy(space
));
3060 map
= isl_map_eliminate(map
, isl_dim_out
, depth
, 1);
3061 map
= isl_map_insert_dims(map
, isl_dim_out
, depth
+ 1, 1);
3062 space
= isl_space_insert_dims(space
, isl_dim_out
, depth
+ 1, 1);
3064 c
= isl_equality_alloc(isl_local_space_from_space(space
));
3065 c
= isl_constraint_set_coefficient_si(c
, isl_dim_in
, depth
, 1);
3066 c
= isl_constraint_set_coefficient_si(c
, isl_dim_out
, depth
, -1);
3068 for (i
= 0; i
< n
; ++i
) {
3072 v
= isl_multi_val_get_val(offset
, i
);
3075 map_i
= isl_map_copy(map
);
3076 map_i
= isl_map_fix_val(map_i
, isl_dim_out
, depth
+ 1,
3079 c
= isl_constraint_set_constant_val(c
, v
);
3080 map_i
= isl_map_add_constraint(map_i
, isl_constraint_copy(c
));
3082 map_i
= isl_map_apply_domain(isl_map_copy(domain
[order
[i
]].map
),
3084 executed
= isl_union_map_add_map(executed
, map_i
);
3087 isl_constraint_free(c
);
3091 executed
= isl_union_map_free(executed
);
3096 /* Generate code for a single component, after exposing the stride,
3097 * given that the schedule domain is "shifted strided".
3099 * The component inverse schedule is specified as the "map" fields
3100 * of the elements of "domain" indexed by the first "n" elements of "order".
3102 * The schedule domain being "shifted strided" means that the differences
3103 * between the values of the current dimension of domain "i"
3104 * and the values of the current dimension for some reference domain are
3107 * stride * integer + offset[i]
3109 * We first look for the domain with the "smallest" value for the current
3110 * dimension and adjust the offsets such that the offset of the "smallest"
3111 * domain is equal to zero. The other offsets are reduced modulo stride.
3113 * Based on this information, we construct a new inverse schedule in
3114 * contruct_shifted_executed that exposes the stride.
3115 * Since this involves the introduction of a new schedule dimension,
3116 * the build needs to be changed accodingly.
3117 * After computing the AST, the newly introduced dimension needs
3118 * to be removed again from the list of grafts. We do this by plugging
3119 * in a mapping that represents the new schedule domain in terms of the
3120 * old schedule domain.
3122 static __isl_give isl_ast_graft_list
*generate_shift_component(
3123 struct isl_set_map_pair
*domain
, int *order
, int n
,
3124 __isl_keep isl_val
*stride
, __isl_keep isl_multi_val
*offset
,
3125 __isl_take isl_ast_build
*build
)
3127 isl_ast_graft_list
*list
;
3134 isl_multi_aff
*ma
, *zero
;
3135 isl_union_map
*executed
;
3137 ctx
= isl_ast_build_get_ctx(build
);
3138 depth
= isl_ast_build_get_depth(build
);
3140 first
= first_offset(domain
, order
, n
, build
);
3142 return isl_ast_build_free(build
);
3144 mv
= isl_multi_val_copy(offset
);
3145 val
= isl_multi_val_get_val(offset
, first
);
3146 val
= isl_val_neg(val
);
3147 mv
= isl_multi_val_add_val(mv
, val
);
3148 mv
= isl_multi_val_mod_val(mv
, isl_val_copy(stride
));
3150 executed
= contruct_shifted_executed(domain
, order
, n
, stride
, mv
,
3152 space
= isl_ast_build_get_space(build
, 1);
3153 space
= isl_space_map_from_set(space
);
3154 ma
= isl_multi_aff_identity(isl_space_copy(space
));
3155 space
= isl_space_from_domain(isl_space_domain(space
));
3156 space
= isl_space_add_dims(space
, isl_dim_out
, 1);
3157 zero
= isl_multi_aff_zero(space
);
3158 ma
= isl_multi_aff_range_splice(ma
, depth
+ 1, zero
);
3159 build
= isl_ast_build_insert_dim(build
, depth
+ 1);
3160 list
= generate_shifted_component(executed
, build
);
3162 list
= isl_ast_graft_list_preimage_multi_aff(list
, ma
);
3164 isl_multi_val_free(mv
);
3169 /* Generate code for a single component.
3171 * The component inverse schedule is specified as the "map" fields
3172 * of the elements of "domain" indexed by the first "n" elements of "order".
3174 * This function may modify the "set" fields of "domain".
3176 * Before proceeding with the actual code generation for the component,
3177 * we first check if there are any "shifted" strides, meaning that
3178 * the schedule domains of the individual domains are all strided,
3179 * but that they have different offsets, resulting in the union
3180 * of schedule domains not being strided anymore.
3182 * The simplest example is the schedule
3184 * { A[i] -> [2i]: 0 <= i < 10; B[i] -> [2i+1] : 0 <= i < 10 }
3186 * Both schedule domains are strided, but their union is not.
3187 * This function detects such cases and then rewrites the schedule to
3189 * { A[i] -> [2i, 0]: 0 <= i < 10; B[i] -> [2i, 1] : 0 <= i < 10 }
3191 * In the new schedule, the schedule domains have the same offset (modulo
3192 * the stride), ensuring that the union of schedule domains is also strided.
3195 * If there is only a single domain in the component, then there is
3196 * nothing to do. Similarly, if the current schedule dimension has
3197 * a fixed value for almost all domains then there is nothing to be done.
3198 * In particular, we need at least two domains where the current schedule
3199 * dimension does not have a fixed value.
3200 * Finally, if any of the options refer to the current schedule dimension,
3201 * then we bail out as well. It would be possible to reformulate the options
3202 * in terms of the new schedule domain, but that would introduce constraints
3203 * that separate the domains in the options and that is something we would
3207 * To see if there is any shifted stride, we look at the differences
3208 * between the values of the current dimension in pairs of domains
3209 * for equal values of outer dimensions. These differences should be
3214 * with "m" the stride and "r" a constant. Note that we cannot perform
3215 * this analysis on individual domains as the lower bound in each domain
3216 * may depend on parameters or outer dimensions and so the current dimension
3217 * itself may not have a fixed remainder on division by the stride.
3219 * In particular, we compare the first domain that does not have an
3220 * obviously fixed value for the current dimension to itself and all
3221 * other domains and collect the offsets and the gcd of the strides.
3222 * If the gcd becomes one, then we failed to find shifted strides.
3223 * If the gcd is zero, then the differences were all fixed, meaning
3224 * that some domains had non-obviously fixed values for the current dimension.
3225 * If all the offsets are the same (for those domains that do not have
3226 * an obviously fixed value for the current dimension), then we do not
3227 * apply the transformation.
3228 * If none of the domains were skipped, then there is nothing to do.
3229 * If some of them were skipped, then if we apply separation, the schedule
3230 * domain should get split in pieces with a (non-shifted) stride.
3232 * Otherwise, we apply a shift to expose the stride in
3233 * generate_shift_component.
3235 static __isl_give isl_ast_graft_list
*generate_component(
3236 struct isl_set_map_pair
*domain
, int *order
, int n
,
3237 __isl_take isl_ast_build
*build
)
3244 isl_val
*gcd
= NULL
;
3248 isl_ast_graft_list
*list
;
3251 depth
= isl_ast_build_get_depth(build
);
3254 if (skip
>= 0 && !skip
)
3255 skip
= at_most_one_non_fixed(domain
, order
, n
, depth
);
3256 if (skip
>= 0 && !skip
)
3257 skip
= isl_ast_build_options_involve_depth(build
);
3259 return isl_ast_build_free(build
);
3261 return generate_shifted_component_from_list(domain
,
3264 base
= eliminate_non_fixed(domain
, order
, n
, depth
, build
);
3266 return isl_ast_build_free(build
);
3268 ctx
= isl_ast_build_get_ctx(build
);
3270 mv
= isl_multi_val_zero(isl_space_set_alloc(ctx
, 0, n
));
3273 for (i
= 0; i
< n
; ++i
) {
3276 map
= isl_map_from_domain_and_range(
3277 isl_set_copy(domain
[order
[base
]].set
),
3278 isl_set_copy(domain
[order
[i
]].set
));
3279 for (d
= 0; d
< depth
; ++d
)
3280 map
= isl_map_equate(map
, isl_dim_in
, d
,
3282 deltas
= isl_map_deltas(map
);
3283 res
= isl_set_dim_residue_class_val(deltas
, depth
, &m
, &r
);
3284 isl_set_free(deltas
);
3291 gcd
= isl_val_gcd(gcd
, m
);
3292 if (isl_val_is_one(gcd
)) {
3296 mv
= isl_multi_val_set_val(mv
, i
, r
);
3298 res
= dim_is_fixed(domain
[order
[i
]].set
, depth
);
3304 if (fixed
&& i
> base
) {
3306 a
= isl_multi_val_get_val(mv
, i
);
3307 b
= isl_multi_val_get_val(mv
, base
);
3308 if (isl_val_ne(a
, b
))
3315 if (res
< 0 || !gcd
) {
3316 isl_ast_build_free(build
);
3318 } else if (i
< n
|| fixed
|| isl_val_is_zero(gcd
)) {
3319 list
= generate_shifted_component_from_list(domain
,
3322 list
= generate_shift_component(domain
, order
, n
, gcd
, mv
,
3327 isl_multi_val_free(mv
);
3332 /* Store both "map" itself and its domain in the
3333 * structure pointed to by *next and advance to the next array element.
3335 static int extract_domain(__isl_take isl_map
*map
, void *user
)
3337 struct isl_set_map_pair
**next
= user
;
3339 (*next
)->map
= isl_map_copy(map
);
3340 (*next
)->set
= isl_map_domain(map
);
3346 /* Internal data for any_scheduled_after.
3348 * "depth" is the number of loops that have already been generated
3349 * "group_coscheduled" is a local copy of options->ast_build_group_coscheduled
3350 * "domain" is an array of set-map pairs corresponding to the different
3351 * iteration domains. The set is the schedule domain, i.e., the domain
3352 * of the inverse schedule, while the map is the inverse schedule itself.
3354 struct isl_any_scheduled_after_data
{
3356 int group_coscheduled
;
3357 struct isl_set_map_pair
*domain
;
3360 /* Is any element of domain "i" scheduled after any element of domain "j"
3361 * (for a common iteration of the first data->depth loops)?
3363 * data->domain[i].set contains the domain of the inverse schedule
3364 * for domain "i", i.e., elements in the schedule domain.
3366 * If data->group_coscheduled is set, then we also return 1 if there
3367 * is any pair of elements in the two domains that are scheduled together.
3369 static int any_scheduled_after(int i
, int j
, void *user
)
3371 struct isl_any_scheduled_after_data
*data
= user
;
3372 int dim
= isl_set_dim(data
->domain
[i
].set
, isl_dim_set
);
3375 for (pos
= data
->depth
; pos
< dim
; ++pos
) {
3378 follows
= isl_set_follows_at(data
->domain
[i
].set
,
3379 data
->domain
[j
].set
, pos
);
3389 return data
->group_coscheduled
;
3392 /* Look for independent components at the current depth and generate code
3393 * for each component separately. The resulting lists of grafts are
3394 * merged in an attempt to combine grafts with identical guards.
3396 * Code for two domains can be generated separately if all the elements
3397 * of one domain are scheduled before (or together with) all the elements
3398 * of the other domain. We therefore consider the graph with as nodes
3399 * the domains and an edge between two nodes if any element of the first
3400 * node is scheduled after any element of the second node.
3401 * If the ast_build_group_coscheduled is set, then we also add an edge if
3402 * there is any pair of elements in the two domains that are scheduled
3404 * Code is then generated (by generate_component)
3405 * for each of the strongly connected components in this graph
3406 * in their topological order.
3408 * Since the test is performed on the domain of the inverse schedules of
3409 * the different domains, we precompute these domains and store
3410 * them in data.domain.
3412 static __isl_give isl_ast_graft_list
*generate_components(
3413 __isl_take isl_union_map
*executed
, __isl_take isl_ast_build
*build
)
3416 isl_ctx
*ctx
= isl_ast_build_get_ctx(build
);
3417 int n
= isl_union_map_n_map(executed
);
3418 struct isl_any_scheduled_after_data data
;
3419 struct isl_set_map_pair
*next
;
3420 struct isl_tarjan_graph
*g
= NULL
;
3421 isl_ast_graft_list
*list
= NULL
;
3424 data
.domain
= isl_calloc_array(ctx
, struct isl_set_map_pair
, n
);
3430 if (isl_union_map_foreach_map(executed
, &extract_domain
, &next
) < 0)
3435 data
.depth
= isl_ast_build_get_depth(build
);
3436 data
.group_coscheduled
= isl_options_get_ast_build_group_coscheduled(ctx
);
3437 g
= isl_tarjan_graph_init(ctx
, n
, &any_scheduled_after
, &data
);
3439 list
= isl_ast_graft_list_alloc(ctx
, 0);
3443 isl_ast_graft_list
*list_c
;
3446 if (g
->order
[i
] == -1)
3447 isl_die(ctx
, isl_error_internal
, "cannot happen",
3450 while (g
->order
[i
] != -1) {
3454 list_c
= generate_component(data
.domain
,
3455 g
->order
+ first
, i
- first
,
3456 isl_ast_build_copy(build
));
3457 list
= isl_ast_graft_list_merge(list
, list_c
, build
);
3463 error
: list
= isl_ast_graft_list_free(list
);
3464 isl_tarjan_graph_free(g
);
3465 for (i
= 0; i
< n_domain
; ++i
) {
3466 isl_map_free(data
.domain
[i
].map
);
3467 isl_set_free(data
.domain
[i
].set
);
3470 isl_union_map_free(executed
);
3471 isl_ast_build_free(build
);
3476 /* Generate code for the next level (and all inner levels).
3478 * If "executed" is empty, i.e., no code needs to be generated,
3479 * then we return an empty list.
3481 * If we have already generated code for all loop levels, then we pass
3482 * control to generate_inner_level.
3484 * If "executed" lives in a single space, i.e., if code needs to be
3485 * generated for a single domain, then there can only be a single
3486 * component and we go directly to generate_shifted_component.
3487 * Otherwise, we call generate_components to detect the components
3488 * and to call generate_component on each of them separately.
3490 static __isl_give isl_ast_graft_list
*generate_next_level(
3491 __isl_take isl_union_map
*executed
, __isl_take isl_ast_build
*build
)
3495 if (!build
|| !executed
)
3498 if (isl_union_map_is_empty(executed
)) {
3499 isl_ctx
*ctx
= isl_ast_build_get_ctx(build
);
3500 isl_union_map_free(executed
);
3501 isl_ast_build_free(build
);
3502 return isl_ast_graft_list_alloc(ctx
, 0);
3505 depth
= isl_ast_build_get_depth(build
);
3506 if (depth
>= isl_set_dim(build
->domain
, isl_dim_set
))
3507 return generate_inner_level(executed
, build
);
3509 if (isl_union_map_n_map(executed
) == 1)
3510 return generate_shifted_component(executed
, build
);
3512 return generate_components(executed
, build
);
3514 isl_union_map_free(executed
);
3515 isl_ast_build_free(build
);
3519 /* Internal data structure used by isl_ast_build_ast_from_schedule.
3520 * internal, executed and build are the inputs to generate_code.
3521 * list collects the output.
3523 struct isl_generate_code_data
{
3525 isl_union_map
*executed
;
3526 isl_ast_build
*build
;
3528 isl_ast_graft_list
*list
;
3531 /* Given an inverse schedule in terms of the external build schedule, i.e.,
3535 * with E the external build schedule and S the additional schedule "space",
3536 * reformulate the inverse schedule in terms of the internal schedule domain,
3541 * We first obtain a mapping
3545 * take the inverse and the product with S -> S, resulting in
3547 * [I -> S] -> [E -> S]
3549 * Applying the map to the input produces the desired result.
3551 static __isl_give isl_union_map
*internal_executed(
3552 __isl_take isl_union_map
*executed
, __isl_keep isl_space
*space
,
3553 __isl_keep isl_ast_build
*build
)
3557 proj
= isl_ast_build_get_schedule_map(build
);
3558 proj
= isl_map_reverse(proj
);
3559 space
= isl_space_map_from_set(isl_space_copy(space
));
3560 id
= isl_map_identity(space
);
3561 proj
= isl_map_product(proj
, id
);
3562 executed
= isl_union_map_apply_domain(executed
,
3563 isl_union_map_from_map(proj
));
3567 /* Generate an AST that visits the elements in the range of data->executed
3568 * in the relative order specified by the corresponding image element(s)
3569 * for those image elements that belong to "set".
3570 * Add the result to data->list.
3572 * The caller ensures that "set" is a universe domain.
3573 * "space" is the space of the additional part of the schedule.
3574 * It is equal to the space of "set" if build->domain is parametric.
3575 * Otherwise, it is equal to the range of the wrapped space of "set".
3577 * If the build space is not parametric and if isl_ast_build_ast_from_schedule
3578 * was called from an outside user (data->internal not set), then
3579 * the (inverse) schedule refers to the external build domain and needs to
3580 * be transformed to refer to the internal build domain.
3582 * The build is extended to include the additional part of the schedule.
3583 * If the original build space was not parametric, then the options
3584 * in data->build refer only to the additional part of the schedule
3585 * and they need to be adjusted to refer to the complete AST build
3588 * After having adjusted inverse schedule and build, we start generating
3589 * code with the outer loop of the current code generation
3590 * in generate_next_level.
3592 * If the original build space was not parametric, we undo the embedding
3593 * on the resulting isl_ast_node_list so that it can be used within
3594 * the outer AST build.
3596 static int generate_code_in_space(struct isl_generate_code_data
*data
,
3597 __isl_take isl_set
*set
, __isl_take isl_space
*space
)
3599 isl_union_map
*executed
;
3600 isl_ast_build
*build
;
3601 isl_ast_graft_list
*list
;
3604 executed
= isl_union_map_copy(data
->executed
);
3605 executed
= isl_union_map_intersect_domain(executed
,
3606 isl_union_set_from_set(set
));
3608 embed
= !isl_set_is_params(data
->build
->domain
);
3609 if (embed
&& !data
->internal
)
3610 executed
= internal_executed(executed
, space
, data
->build
);
3612 build
= isl_ast_build_copy(data
->build
);
3613 build
= isl_ast_build_product(build
, space
);
3615 list
= generate_next_level(executed
, build
);
3617 list
= isl_ast_graft_list_unembed(list
, embed
);
3619 data
->list
= isl_ast_graft_list_concat(data
->list
, list
);
3624 /* Generate an AST that visits the elements in the range of data->executed
3625 * in the relative order specified by the corresponding domain element(s)
3626 * for those domain elements that belong to "set".
3627 * Add the result to data->list.
3629 * The caller ensures that "set" is a universe domain.
3631 * If the build space S is not parametric, then the space of "set"
3632 * need to be a wrapped relation with S as domain. That is, it needs
3637 * Check this property and pass control to generate_code_in_space
3639 * If the build space is not parametric, then T is the space of "set".
3641 static int generate_code_set(__isl_take isl_set
*set
, void *user
)
3643 struct isl_generate_code_data
*data
= user
;
3644 isl_space
*space
, *build_space
;
3647 space
= isl_set_get_space(set
);
3649 if (isl_set_is_params(data
->build
->domain
))
3650 return generate_code_in_space(data
, set
, space
);
3652 build_space
= isl_ast_build_get_space(data
->build
, data
->internal
);
3653 space
= isl_space_unwrap(space
);
3654 is_domain
= isl_space_is_domain(build_space
, space
);
3655 isl_space_free(build_space
);
3656 space
= isl_space_range(space
);
3661 isl_die(isl_set_get_ctx(set
), isl_error_invalid
,
3662 "invalid nested schedule space", goto error
);
3664 return generate_code_in_space(data
, set
, space
);
3667 isl_space_free(space
);
3671 /* Generate an AST that visits the elements in the range of "executed"
3672 * in the relative order specified by the corresponding domain element(s).
3674 * "build" is an isl_ast_build that has either been constructed by
3675 * isl_ast_build_from_context or passed to a callback set by
3676 * isl_ast_build_set_create_leaf.
3677 * In the first case, the space of the isl_ast_build is typically
3678 * a parametric space, although this is currently not enforced.
3679 * In the second case, the space is never a parametric space.
3680 * If the space S is not parametric, then the domain space(s) of "executed"
3681 * need to be wrapped relations with S as domain.
3683 * If the domain of "executed" consists of several spaces, then an AST
3684 * is generated for each of them (in arbitrary order) and the results
3687 * If "internal" is set, then the domain "S" above refers to the internal
3688 * schedule domain representation. Otherwise, it refers to the external
3689 * representation, as returned by isl_ast_build_get_schedule_space.
3691 * We essentially run over all the spaces in the domain of "executed"
3692 * and call generate_code_set on each of them.
3694 static __isl_give isl_ast_graft_list
*generate_code(
3695 __isl_take isl_union_map
*executed
, __isl_take isl_ast_build
*build
,
3699 struct isl_generate_code_data data
= { 0 };
3701 isl_union_set
*schedule_domain
;
3702 isl_union_map
*universe
;
3706 space
= isl_ast_build_get_space(build
, 1);
3707 space
= isl_space_align_params(space
,
3708 isl_union_map_get_space(executed
));
3709 space
= isl_space_align_params(space
,
3710 isl_union_map_get_space(build
->options
));
3711 build
= isl_ast_build_align_params(build
, isl_space_copy(space
));
3712 executed
= isl_union_map_align_params(executed
, space
);
3713 if (!executed
|| !build
)
3716 ctx
= isl_ast_build_get_ctx(build
);
3718 data
.internal
= internal
;
3719 data
.executed
= executed
;
3721 data
.list
= isl_ast_graft_list_alloc(ctx
, 0);
3723 universe
= isl_union_map_universe(isl_union_map_copy(executed
));
3724 schedule_domain
= isl_union_map_domain(universe
);
3725 if (isl_union_set_foreach_set(schedule_domain
, &generate_code_set
,
3727 data
.list
= isl_ast_graft_list_free(data
.list
);
3729 isl_union_set_free(schedule_domain
);
3730 isl_union_map_free(executed
);
3732 isl_ast_build_free(build
);
3735 isl_union_map_free(executed
);
3736 isl_ast_build_free(build
);
3740 /* Generate an AST that visits the elements in the domain of "schedule"
3741 * in the relative order specified by the corresponding image element(s).
3743 * "build" is an isl_ast_build that has either been constructed by
3744 * isl_ast_build_from_context or passed to a callback set by
3745 * isl_ast_build_set_create_leaf.
3746 * In the first case, the space of the isl_ast_build is typically
3747 * a parametric space, although this is currently not enforced.
3748 * In the second case, the space is never a parametric space.
3749 * If the space S is not parametric, then the range space(s) of "schedule"
3750 * need to be wrapped relations with S as domain.
3752 * If the range of "schedule" consists of several spaces, then an AST
3753 * is generated for each of them (in arbitrary order) and the results
3756 * We first initialize the local copies of the relevant options.
3757 * We do this here rather than when the isl_ast_build is created
3758 * because the options may have changed between the construction
3759 * of the isl_ast_build and the call to isl_generate_code.
3761 * The main computation is performed on an inverse schedule (with
3762 * the schedule domain in the domain and the elements to be executed
3763 * in the range) called "executed".
3765 __isl_give isl_ast_node
*isl_ast_build_ast_from_schedule(
3766 __isl_keep isl_ast_build
*build
, __isl_take isl_union_map
*schedule
)
3768 isl_ast_graft_list
*list
;
3770 isl_union_map
*executed
;
3772 build
= isl_ast_build_copy(build
);
3773 build
= isl_ast_build_set_single_valued(build
, 0);
3774 executed
= isl_union_map_reverse(schedule
);
3775 list
= generate_code(executed
, isl_ast_build_copy(build
), 0);
3776 node
= isl_ast_node_from_graft_list(list
, build
);
3777 isl_ast_build_free(build
);