X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=isl_flow.c;h=68fa0d9ac1f688a0599b857068eb4d0834620c31;hb=7bc3560a92635b5dcf7eb9e7329992fc935a1ce2;hp=d5dcb487af37f1551e9513f3cd67504c31a171d4;hpb=fcba3621a2b9ef737f534b5a1f8eae1cf9ef23be;p=platform%2Fupstream%2Fisl.git

diff --git a/isl_flow.c b/isl_flow.c
index d5dcb48..68fa0d9 100644
--- a/isl_flow.c
+++ b/isl_flow.c
@@ -2,8 +2,9 @@
  * Copyright 2005-2007 Universiteit Leiden
  * Copyright 2008-2009 Katholieke Universiteit Leuven
  * Copyright 2010      INRIA Saclay
+ * Copyright 2012      Universiteit Leiden
  *
- * Use of this software is governed by the GNU LGPLv2.1 license
+ * Use of this software is governed by the MIT license
  *
  * Written by Sven Verdoolaege, Leiden Institute of Advanced Computer Science,
  * Universiteit Leiden, Niels Bohrweg 1, 2333 CA Leiden, The Netherlands
@@ -13,7 +14,134 @@
  * ZAC des vignes, 4 rue Jacques Monod, 91893 Orsay, France 
  */
 
-#include <isl_flow.h>
+#include <isl/set.h>
+#include <isl/map.h>
+#include <isl/flow.h>
+#include <isl_sort.h>
+
+enum isl_restriction_type {
+	isl_restriction_type_empty,
+	isl_restriction_type_none,
+	isl_restriction_type_input,
+	isl_restriction_type_output
+};
+
+struct isl_restriction {
+	enum isl_restriction_type type;
+
+	isl_set *source;
+	isl_set *sink;
+};
+
+/* Create a restriction of the given type.
+ */
+static __isl_give isl_restriction *isl_restriction_alloc(
+	__isl_take isl_map *source_map, enum isl_restriction_type type)
+{
+	isl_ctx *ctx;
+	isl_restriction *restr;
+
+	if (!source_map)
+		return NULL;
+
+	ctx = isl_map_get_ctx(source_map);
+	restr = isl_calloc_type(ctx, struct isl_restriction);
+	if (!restr)
+		goto error;
+
+	restr->type = type;
+
+	isl_map_free(source_map);
+	return restr;
+error:
+	isl_map_free(source_map);
+	return NULL;
+}
+
+/* Create a restriction that doesn't restrict anything.
+ */
+__isl_give isl_restriction *isl_restriction_none(__isl_take isl_map *source_map)
+{
+	return isl_restriction_alloc(source_map, isl_restriction_type_none);
+}
+
+/* Create a restriction that removes everything.
+ */
+__isl_give isl_restriction *isl_restriction_empty(
+	__isl_take isl_map *source_map)
+{
+	return isl_restriction_alloc(source_map, isl_restriction_type_empty);
+}
+
+/* Create a restriction on the input of the maximization problem
+ * based on the given source and sink restrictions.
+ */
+__isl_give isl_restriction *isl_restriction_input(
+	__isl_take isl_set *source_restr, __isl_take isl_set *sink_restr)
+{
+	isl_ctx *ctx;
+	isl_restriction *restr;
+
+	if (!source_restr || !sink_restr)
+		goto error;
+
+	ctx = isl_set_get_ctx(source_restr);
+	restr = isl_calloc_type(ctx, struct isl_restriction);
+	if (!restr)
+		goto error;
+
+	restr->type = isl_restriction_type_input;
+	restr->source = source_restr;
+	restr->sink = sink_restr;
+
+	return restr;
+error:
+	isl_set_free(source_restr);
+	isl_set_free(sink_restr);
+	return NULL;
+}
+
+/* Create a restriction on the output of the maximization problem
+ * based on the given source restriction.
+ */
+__isl_give isl_restriction *isl_restriction_output(
+	__isl_take isl_set *source_restr)
+{
+	isl_ctx *ctx;
+	isl_restriction *restr;
+
+	if (!source_restr)
+		return NULL;
+
+	ctx = isl_set_get_ctx(source_restr);
+	restr = isl_calloc_type(ctx, struct isl_restriction);
+	if (!restr)
+		goto error;
+
+	restr->type = isl_restriction_type_output;
+	restr->source = source_restr;
+
+	return restr;
+error:
+	isl_set_free(source_restr);
+	return NULL;
+}
+
+void *isl_restriction_free(__isl_take isl_restriction *restr)
+{
+	if (!restr)
+		return NULL;
+
+	isl_set_free(restr->source);
+	isl_set_free(restr->sink);
+	free(restr);
+	return NULL;
+}
+
+isl_ctx *isl_restriction_get_ctx(__isl_keep isl_restriction *restr)
+{
+	return restr ? isl_set_get_ctx(restr->source) : NULL;
+}
 
 /* A private structure to keep track of a mapping together with
  * a user-specified identifier and a boolean indicating whether
@@ -30,20 +158,31 @@ struct isl_labeled_map {
  * - n_must + n_may (<= max_source) sources
  * - a function for determining the relative order of sources and sink
  * The must sources are placed before the may sources.
+ *
+ * domain_map is an auxiliary map that maps the sink access relation
+ * to the domain of this access relation.
+ *
+ * restrict_fn is a callback that (if not NULL) will be called
+ * right before any lexicographical maximization.
  */
 struct isl_access_info {
-	struct isl_labeled_map	sink;
-	isl_access_level_before	level_before;
-	int		    	max_source;
-	int		    	n_must;
-	int		    	n_may;
-	struct isl_labeled_map	source[1];
+	isl_map				*domain_map;
+	struct isl_labeled_map		sink;
+	isl_access_level_before		level_before;
+
+	isl_access_restrict		restrict_fn;
+	void				*restrict_user;
+
+	int		    		max_source;
+	int		    		n_must;
+	int		    		n_may;
+	struct isl_labeled_map		source[1];
 };
 
 /* A structure containing the output of dependence analysis:
  * - n_source dependences
- * - a subset of the sink for which definitely no source could be found
- * - a subset of the sink for which possibly no source could be found
+ * - a wrapped subset of the sink for which definitely no source could be found
+ * - a wrapped subset of the sink for which possibly no source could be found
  */
 struct isl_flow {
 	isl_set			*must_no_source;
@@ -58,14 +197,16 @@ struct isl_flow {
 __isl_give isl_access_info *isl_access_info_alloc(__isl_take isl_map *sink,
 	void *sink_user, isl_access_level_before fn, int max_source)
 {
+	isl_ctx *ctx;
 	struct isl_access_info *acc;
 
 	if (!sink)
 		return NULL;
 
-	isl_assert(sink->ctx, max_source >= 0, goto error);
+	ctx = isl_map_get_ctx(sink);
+	isl_assert(ctx, max_source >= 0, goto error);
 
-	acc = isl_alloc(sink->ctx, struct isl_access_info,
+	acc = isl_calloc(ctx, struct isl_access_info,
 			sizeof(struct isl_access_info) +
 			(max_source - 1) * sizeof(struct isl_labeled_map));
 	if (!acc)
@@ -85,20 +226,34 @@ error:
 }
 
 /* Free the given isl_access_info structure.
- * This function is static because the user is expected to call
- * isl_access_info_compute_flow on any isl_access_info structure
- * he creates.
  */
-static void isl_access_info_free(__isl_take isl_access_info *acc)
+void *isl_access_info_free(__isl_take isl_access_info *acc)
 {
 	int i;
 
 	if (!acc)
-		return;
+		return NULL;
+	isl_map_free(acc->domain_map);
 	isl_map_free(acc->sink.map);
 	for (i = 0; i < acc->n_must + acc->n_may; ++i)
 		isl_map_free(acc->source[i].map);
 	free(acc);
+	return NULL;
+}
+
+isl_ctx *isl_access_info_get_ctx(__isl_keep isl_access_info *acc)
+{
+	return acc ? isl_map_get_ctx(acc->sink.map) : NULL;
+}
+
+__isl_give isl_access_info *isl_access_info_set_restrict(
+	__isl_take isl_access_info *acc, isl_access_restrict fn, void *user)
+{
+	if (!acc)
+		return NULL;
+	acc->restrict_fn = fn;
+	acc->restrict_user = user;
+	return acc;
 }
 
 /* Add another source to an isl_access_info structure, making
@@ -111,10 +266,12 @@ __isl_give isl_access_info *isl_access_info_add_source(
 	__isl_take isl_access_info *acc, __isl_take isl_map *source,
 	int must, void *source_user)
 {
+	isl_ctx *ctx;
+
 	if (!acc)
-		return NULL;
-	isl_assert(acc->sink.map->ctx,
-		    acc->n_must + acc->n_may < acc->max_source, goto error);
+		goto error;
+	ctx = isl_map_get_ctx(acc->sink.map);
+	isl_assert(ctx, acc->n_must + acc->n_may < acc->max_source, goto error);
 	
 	if (must) {
 		if (acc->n_may)
@@ -138,83 +295,70 @@ error:
 	return NULL;
 }
 
-/* A temporary structure used while sorting the accesses in an isl_access_info.
- */
-struct isl_access_sort_info {
-	struct isl_map		*source_map;
-	void			*source_data;
-	struct isl_access_info	*acc;
-};
-
 /* Return -n, 0 or n (with n a positive value), depending on whether
  * the source access identified by p1 should be sorted before, together
  * or after that identified by p2.
  *
- * If p1 and p2 share a different number of levels with the sink,
- * then the one with the lowest number of shared levels should be
- * sorted first.
- * If they both share no levels, then the order is irrelevant.
- * Otherwise, if p1 appears before p2, then it should be sorted first.
+ * If p1 appears before p2, then it should be sorted first.
+ * For more generic initial schedules, it is possible that neither
+ * p1 nor p2 appears before the other, or at least not in any obvious way.
+ * We therefore also check if p2 appears before p1, in which case p2
+ * should be sorted first.
+ * If not, we try to order the two statements based on the description
+ * of the iteration domains.  This results in an arbitrary, but fairly
+ * stable ordering.
  */
-static int access_sort_cmp(const void *p1, const void *p2)
+static int access_sort_cmp(const void *p1, const void *p2, void *user)
 {
-	const struct isl_access_sort_info *i1, *i2;
+	isl_access_info *acc = user;
+	const struct isl_labeled_map *i1, *i2;
 	int level1, level2;
-	i1 = (const struct isl_access_sort_info *) p1;
-	i2 = (const struct isl_access_sort_info *) p2;
+	uint32_t h1, h2;
+	i1 = (const struct isl_labeled_map *) p1;
+	i2 = (const struct isl_labeled_map *) p2;
 
-	level1 = i1->acc->level_before(i1->source_data, i1->acc->sink.data);
-	level2 = i2->acc->level_before(i2->source_data, i2->acc->sink.data);
-
-	if (level1 != level2 || !level1)
-		return level1 - level2;
+	level1 = acc->level_before(i1->data, i2->data);
+	if (level1 % 2)
+		return -1;
 
-	level1 = i1->acc->level_before(i1->source_data, i2->source_data);
+	level2 = acc->level_before(i2->data, i1->data);
+	if (level2 % 2)
+		return 1;
 
-	return (level1 % 2) ? -1 : 1;
+	h1 = isl_map_get_hash(i1->map);
+	h2 = isl_map_get_hash(i2->map);
+	return h1 > h2 ? 1 : h1 < h2 ? -1 : 0;
 }
 
-/* Sort the must source accesses in order of increasing number of shared
- * levels with the sink access.
- * Source accesses with the same number of shared levels are sorted
- * in their textual order.
+/* Sort the must source accesses in their textual order.
  */
 static __isl_give isl_access_info *isl_access_info_sort_sources(
 	__isl_take isl_access_info *acc)
 {
-	int i;
-	struct isl_access_sort_info *array;
-
 	if (!acc)
 		return NULL;
 	if (acc->n_must <= 1)
 		return acc;
 
-	array = isl_alloc_array(acc->sink.map->ctx,
-				struct isl_access_sort_info, acc->n_must);
-	if (!array)
-		goto error;
+	if (isl_sort(acc->source, acc->n_must, sizeof(struct isl_labeled_map),
+		    access_sort_cmp, acc) < 0)
+		return isl_access_info_free(acc);
 
-	for (i = 0; i < acc->n_must; ++i) {
-		array[i].source_map = acc->source[i].map;
-		array[i].source_data = acc->source[i].data;
-		array[i].acc = acc;
-	}
-
-	qsort(array, acc->n_must, sizeof(struct isl_access_sort_info),
-		access_sort_cmp);
-
-	for (i = 0; i < acc->n_must; ++i) {
-		acc->source[i].map = array[i].source_map;
-		acc->source[i].data = array[i].source_data;
-	}
+	return acc;
+}
 
-	free(array);
+/* Align the parameters of the two spaces if needed and then call
+ * isl_space_join.
+ */
+static __isl_give isl_space *space_align_and_join(__isl_take isl_space *left,
+	__isl_take isl_space *right)
+{
+	if (isl_space_match(left, isl_dim_param, right, isl_dim_param))
+		return isl_space_join(left, right);
 
-	return acc;
-error:
-	isl_access_info_free(acc);
-	return NULL;
+	left = isl_space_align_params(left, isl_space_copy(right));
+	right = isl_space_align_params(right, isl_space_copy(left));
+	return isl_space_join(left, right);
 }
 
 /* Initialize an empty isl_flow structure corresponding to a given
@@ -236,35 +380,41 @@ static __isl_give isl_flow *isl_flow_alloc(__isl_keep isl_access_info *acc)
 	if (!acc)
 		return NULL;
 
-	ctx = acc->sink.map->ctx;
+	ctx = isl_map_get_ctx(acc->sink.map);
 	dep = isl_calloc_type(ctx, struct isl_flow);
 	if (!dep)
 		return NULL;
 
-	dep->dep = isl_alloc_array(ctx, struct isl_labeled_map,
+	dep->dep = isl_calloc_array(ctx, struct isl_labeled_map,
 					2 * acc->n_must + acc->n_may);
 	if (!dep->dep)
 		goto error;
 
 	dep->n_source = 2 * acc->n_must + acc->n_may;
 	for (i = 0; i < acc->n_must; ++i) {
-		struct isl_dim *dim;
-		dim = isl_dim_join(isl_dim_copy(acc->source[i].map->dim),
-			    isl_dim_reverse(isl_dim_copy(acc->sink.map->dim)));
+		isl_space *dim;
+		dim = space_align_and_join(
+			isl_map_get_space(acc->source[i].map),
+			isl_space_reverse(isl_map_get_space(acc->sink.map)));
 		dep->dep[2 * i].map = isl_map_empty(dim);
 		dep->dep[2 * i + 1].map = isl_map_copy(dep->dep[2 * i].map);
 		dep->dep[2 * i].data = acc->source[i].data;
 		dep->dep[2 * i + 1].data = acc->source[i].data;
 		dep->dep[2 * i].must = 1;
 		dep->dep[2 * i + 1].must = 0;
+		if (!dep->dep[2 * i].map || !dep->dep[2 * i + 1].map)
+			goto error;
 	}
 	for (i = acc->n_must; i < acc->n_must + acc->n_may; ++i) {
-		struct isl_dim *dim;
-		dim = isl_dim_join(isl_dim_copy(acc->source[i].map->dim),
-			    isl_dim_reverse(isl_dim_copy(acc->sink.map->dim)));
+		isl_space *dim;
+		dim = space_align_and_join(
+			isl_map_get_space(acc->source[i].map),
+			isl_space_reverse(isl_map_get_space(acc->sink.map)));
 		dep->dep[acc->n_must + i].map = isl_map_empty(dim);
 		dep->dep[acc->n_must + i].data = acc->source[i].data;
 		dep->dep[acc->n_must + i].must = 0;
+		if (!dep->dep[acc->n_must + i].map)
+			goto error;
 	}
 
 	return dep;
@@ -289,7 +439,7 @@ int isl_flow_foreach(__isl_keep isl_flow *deps,
 		return -1;
 
 	for (i = 0; i < deps->n_source; ++i) {
-		if (isl_map_fast_is_empty(deps->dep[i].map))
+		if (isl_map_plain_is_empty(deps->dep[i].map))
 			continue;
 		if (fn(isl_map_copy(deps->dep[i].map), deps->dep[i].must,
 				deps->dep[i].data, user) < 0)
@@ -301,15 +451,15 @@ int isl_flow_foreach(__isl_keep isl_flow *deps,
 
 /* Return a copy of the subset of the sink for which no source could be found.
  */
-__isl_give isl_set *isl_flow_get_no_source(__isl_keep isl_flow *deps, int must)
+__isl_give isl_map *isl_flow_get_no_source(__isl_keep isl_flow *deps, int must)
 {
 	if (!deps)
 		return NULL;
 	
 	if (must)
-		return isl_set_copy(deps->must_no_source);
+		return isl_set_unwrap(isl_set_copy(deps->must_no_source));
 	else
-		return isl_set_copy(deps->may_no_source);
+		return isl_set_unwrap(isl_set_copy(deps->may_no_source));
 }
 
 void isl_flow_free(__isl_take isl_flow *deps)
@@ -328,6 +478,11 @@ void isl_flow_free(__isl_take isl_flow *deps)
 	free(deps);
 }
 
+isl_ctx *isl_flow_get_ctx(__isl_keep isl_flow *deps)
+{
+	return deps ? isl_set_get_ctx(deps->must_no_source) : NULL;
+}
+
 /* Return a map that enforces that the domain iteration occurs after
  * the range iteration at the given level.
  * If level is odd, then the domain iteration should occur after
@@ -338,7 +493,7 @@ void isl_flow_free(__isl_take isl_flow *deps)
  * be greater than the loop iterator of the range at the last
  * of the level/2 shared loops, i.e., loop level/2 - 1.
  */
-static __isl_give isl_map *after_at_level(struct isl_dim *dim, int level)
+static __isl_give isl_map *after_at_level(__isl_take isl_space *dim, int level)
 {
 	struct isl_basic_map *bmap;
 
@@ -350,6 +505,69 @@ static __isl_give isl_map *after_at_level(struct isl_dim *dim, int level)
 	return isl_map_from_basic_map(bmap);
 }
 
+/* Compute the partial lexicographic maximum of "dep" on domain "sink",
+ * but first check if the user has set acc->restrict_fn and if so
+ * update either the input or the output of the maximization problem
+ * with respect to the resulting restriction.
+ *
+ * Since the user expects a mapping from sink iterations to source iterations,
+ * whereas the domain of "dep" is a wrapped map, mapping sink iterations
+ * to accessed array elements, we first need to project out the accessed
+ * sink array elements by applying acc->domain_map.
+ * Similarly, the sink restriction specified by the user needs to be
+ * converted back to the wrapped map.
+ */
+static __isl_give isl_map *restricted_partial_lexmax(
+	__isl_keep isl_access_info *acc, __isl_take isl_map *dep,
+	int source, __isl_take isl_set *sink, __isl_give isl_set **empty)
+{
+	isl_map *source_map;
+	isl_restriction *restr;
+	isl_set *sink_domain;
+	isl_set *sink_restr;
+	isl_map *res;
+
+	if (!acc->restrict_fn)
+		return isl_map_partial_lexmax(dep, sink, empty);
+
+	source_map = isl_map_copy(dep);
+	source_map = isl_map_apply_domain(source_map,
+					    isl_map_copy(acc->domain_map));
+	sink_domain = isl_set_copy(sink);
+	sink_domain = isl_set_apply(sink_domain, isl_map_copy(acc->domain_map));
+	restr = acc->restrict_fn(source_map, sink_domain,
+				acc->source[source].data, acc->restrict_user);
+	isl_set_free(sink_domain);
+	isl_map_free(source_map);
+
+	if (!restr)
+		goto error;
+	if (restr->type == isl_restriction_type_input) {
+		dep = isl_map_intersect_range(dep, isl_set_copy(restr->source));
+		sink_restr = isl_set_copy(restr->sink);
+		sink_restr = isl_set_apply(sink_restr,
+				isl_map_reverse(isl_map_copy(acc->domain_map)));
+		sink = isl_set_intersect(sink, sink_restr);
+	} else if (restr->type == isl_restriction_type_empty) {
+		isl_space *space = isl_map_get_space(dep);
+		isl_map_free(dep);
+		dep = isl_map_empty(space);
+	}
+
+	res = isl_map_partial_lexmax(dep, sink, empty);
+
+	if (restr->type == isl_restriction_type_output)
+		res = isl_map_intersect_range(res, isl_set_copy(restr->source));
+
+	isl_restriction_free(restr);
+	return res;
+error:
+	isl_map_free(dep);
+	isl_set_free(sink);
+	*empty = NULL;
+	return NULL;
+}
+
 /* Compute the last iteration of must source j that precedes the sink
  * at the given level for sink iterations in set_C.
  * The subset of set_C for which no such iteration can be found is returned
@@ -369,9 +587,9 @@ static struct isl_map *last_source(struct isl_access_info *acc,
 	write_map = isl_map_copy(acc->source[j].map);
 	write_map = isl_map_reverse(write_map);
 	dep_map = isl_map_apply_range(read_map, write_map);
-	after = after_at_level(isl_dim_copy(dep_map->dim), level);
+	after = after_at_level(isl_map_get_space(dep_map), level);
 	dep_map = isl_map_intersect(dep_map, after);
-	result = isl_map_partial_lexmax(dep_map, set_C, empty);
+	result = restricted_partial_lexmax(acc, dep_map, j, set_C, empty);
 	result = isl_map_reverse(result);
 
 	return result;
@@ -389,7 +607,7 @@ static struct isl_map *last_later_source(struct isl_access_info *acc,
 					 int k, int after_level,
 					 struct isl_set **empty)
 {
-	struct isl_dim *dim;
+	isl_space *dim;
 	struct isl_set *set_C;
 	struct isl_map *read_map;
 	struct isl_map *write_map;
@@ -404,15 +622,15 @@ static struct isl_map *last_later_source(struct isl_access_info *acc,
 
 	write_map = isl_map_reverse(write_map);
 	dep_map = isl_map_apply_range(read_map, write_map);
-	dim = isl_dim_join(isl_dim_copy(acc->source[k].map->dim),
-		    isl_dim_reverse(isl_dim_copy(acc->source[j].map->dim)));
+	dim = space_align_and_join(isl_map_get_space(acc->source[k].map),
+		    isl_space_reverse(isl_map_get_space(acc->source[j].map)));
 	after_write = after_at_level(dim, after_level);
 	after_write = isl_map_apply_range(after_write, old_map);
 	after_write = isl_map_reverse(after_write);
 	dep_map = isl_map_intersect(dep_map, after_write);
-	before_read = after_at_level(isl_dim_copy(dep_map->dim), before_level);
+	before_read = after_at_level(isl_map_get_space(dep_map), before_level);
 	dep_map = isl_map_intersect(dep_map, before_read);
-	result = isl_map_partial_lexmax(dep_map, set_C, empty);
+	result = restricted_partial_lexmax(acc, dep_map, k, set_C, empty);
 	result = isl_map_reverse(result);
 
 	return result;
@@ -453,7 +671,7 @@ static int intermediate_sources(__isl_keep isl_access_info *acc,
 	int k, level;
 	int depth = 2 * isl_map_dim(acc->source[j].map, isl_dim_in) + 1;
 
-	if (isl_map_fast_is_empty(temp_rel[j]))
+	if (isl_map_plain_is_empty(temp_rel[j]))
 		return 0;
 
 	for (k = j - 1; k >= 0; --k) {
@@ -476,7 +694,7 @@ static int intermediate_sources(__isl_keep isl_access_info *acc,
 			copy = isl_map_copy(temp_rel[j]);
 			T = last_later_source(acc, copy, j, sink_level, k,
 					      level, &trest);
-			if (isl_map_fast_is_empty(T)) {
+			if (isl_map_plain_is_empty(T)) {
 				isl_set_free(trest);
 				isl_map_free(T);
 				continue;
@@ -505,7 +723,7 @@ static __isl_give isl_map *all_sources(__isl_keep isl_access_info *acc,
 	write_map = isl_map_copy(acc->source[acc->n_must + j].map);
 	write_map = isl_map_reverse(write_map);
 	dep_map = isl_map_apply_range(read_map, write_map);
-	after = after_at_level(isl_dim_copy(dep_map->dim), level);
+	after = after_at_level(isl_map_get_space(dep_map), level);
 	dep_map = isl_map_intersect(dep_map, after);
 
 	return isl_map_reverse(dep_map);
@@ -521,7 +739,7 @@ static __isl_give isl_map *all_later_sources(__isl_keep isl_access_info *acc,
 	__isl_keep isl_map *old_map,
 	int j, int before_level, int k, int after_level)
 {
-	isl_dim *dim;
+	isl_space *dim;
 	isl_set *set_C;
 	isl_map *read_map;
 	isl_map *write_map;
@@ -536,13 +754,13 @@ static __isl_give isl_map *all_later_sources(__isl_keep isl_access_info *acc,
 
 	write_map = isl_map_reverse(write_map);
 	dep_map = isl_map_apply_range(read_map, write_map);
-	dim = isl_dim_join(isl_dim_copy(acc->source[acc->n_must + j].map->dim),
-		    isl_dim_reverse(isl_dim_copy(acc->source[k].map->dim)));
+	dim = isl_space_join(isl_map_get_space(acc->source[acc->n_must + j].map),
+		    isl_space_reverse(isl_map_get_space(acc->source[k].map)));
 	after_write = after_at_level(dim, after_level);
 	after_write = isl_map_apply_range(after_write, old_map);
 	after_write = isl_map_reverse(after_write);
 	dep_map = isl_map_intersect(dep_map, after_write);
-	before_read = after_at_level(isl_dim_copy(dep_map->dim), before_level);
+	before_read = after_at_level(isl_map_get_space(dep_map), before_level);
 	dep_map = isl_map_intersect(dep_map, before_read);
 	return isl_map_reverse(dep_map);
 }
@@ -566,8 +784,8 @@ static __isl_give isl_map *all_intermediate_sources(
 	for (k = 0; k < acc->n_must; ++k) {
 		int plevel;
 
-		if (isl_map_fast_is_empty(may_rel[k]) &&
-		    isl_map_fast_is_empty(must_rel[k]))
+		if (isl_map_plain_is_empty(may_rel[k]) &&
+		    isl_map_plain_is_empty(must_rel[k]))
 			continue;
 
 		plevel = acc->level_before(acc->source[k].data,
@@ -594,7 +812,7 @@ static __isl_give isl_map *all_intermediate_sources(
 						    isl_set_copy(ran)));
 			T = isl_map_from_domain_and_range(
 			    isl_set_universe(
-				isl_dim_domain(isl_map_get_dim(must_rel[k]))),
+				isl_space_domain(isl_map_get_space(must_rel[k]))),
 			    ran);
 			must_rel[k] = isl_map_subtract(must_rel[k], T);
 		}
@@ -609,7 +827,7 @@ static __isl_give isl_map *all_intermediate_sources(
  * be overkill to use it.
  */
 static __isl_give isl_flow *compute_mem_based_dependences(
-	__isl_take isl_access_info *acc)
+	__isl_keep isl_access_info *acc)
 {
 	int i;
 	isl_set *mustdo;
@@ -618,7 +836,7 @@ static __isl_give isl_flow *compute_mem_based_dependences(
 
 	res = isl_flow_alloc(acc);
 	if (!res)
-		goto error;
+		return NULL;
 
 	mustdo = isl_map_domain(isl_map_copy(acc->sink.map));
 	maydo = isl_set_copy(mustdo);
@@ -626,7 +844,7 @@ static __isl_give isl_flow *compute_mem_based_dependences(
 	for (i = 0; i < acc->n_may; ++i) {
 		int plevel;
 		int is_before;
-		isl_dim *dim;
+		isl_space *dim;
 		isl_map *before;
 		isl_map *dep;
 
@@ -634,7 +852,7 @@ static __isl_give isl_flow *compute_mem_based_dependences(
 		is_before = plevel & 1;
 		plevel >>= 1;
 
-		dim = isl_map_get_dim(res->dep[i].map);
+		dim = isl_map_get_space(res->dep[i].map);
 		if (is_before)
 			before = isl_map_lex_le_first(dim, plevel);
 		else
@@ -650,12 +868,7 @@ static __isl_give isl_flow *compute_mem_based_dependences(
 	res->may_no_source = isl_set_subtract(maydo, isl_set_copy(mustdo));
 	res->must_no_source = mustdo;
 
-	isl_access_info_free(acc);
-
 	return res;
-error:
-	isl_access_info_free(acc);
-	return NULL;
 }
 
 /* Compute dependences for the case where there is at least one
@@ -694,34 +907,37 @@ error:
  * 
  */
 static __isl_give isl_flow *compute_val_based_dependences(
-	__isl_take isl_access_info *acc)
+	__isl_keep isl_access_info *acc)
 {
 	isl_ctx *ctx;
 	isl_flow *res;
-	isl_set *mustdo;
-	isl_set *maydo;
+	isl_set *mustdo = NULL;
+	isl_set *maydo = NULL;
 	int level, j;
 	int depth;
-	isl_map **must_rel;
-	isl_map **may_rel;
+	isl_map **must_rel = NULL;
+	isl_map **may_rel = NULL;
 
-	acc = isl_access_info_sort_sources(acc);
 	if (!acc)
 		return NULL;
 
 	res = isl_flow_alloc(acc);
 	if (!res)
 		goto error;
-	ctx = acc->sink.map->ctx;
+	ctx = isl_map_get_ctx(acc->sink.map);
 
 	depth = 2 * isl_map_dim(acc->sink.map, isl_dim_in) + 1;
 	mustdo = isl_map_domain(isl_map_copy(acc->sink.map));
 	maydo = isl_set_empty_like(mustdo);
-	if (isl_set_fast_is_empty(mustdo))
+	if (!mustdo || !maydo)
+		goto error;
+	if (isl_set_plain_is_empty(mustdo))
 		goto done;
 
 	must_rel = isl_alloc_array(ctx, struct isl_map *, acc->n_must);
 	may_rel = isl_alloc_array(ctx, struct isl_map *, acc->n_must);
+	if (!must_rel || !may_rel)
+		goto error;
 
 	for (level = depth; level >= 1; --level) {
 		for (j = acc->n_must-1; j >=0; --j) {
@@ -751,8 +967,8 @@ static __isl_give isl_flow *compute_val_based_dependences(
 
 			intermediate_sources(acc, may_rel, j, level);
 
-			if (isl_set_fast_is_empty(mustdo) &&
-			    isl_set_fast_is_empty(maydo))
+			if (isl_set_plain_is_empty(mustdo) &&
+			    isl_set_plain_is_empty(maydo))
 				break;
 		}
 		for (j = j - 1; j >= 0; --j) {
@@ -802,8 +1018,8 @@ static __isl_give isl_flow *compute_val_based_dependences(
 							     may_rel[j]);
 		}
 
-		if (isl_set_fast_is_empty(mustdo) &&
-		    isl_set_fast_is_empty(maydo))
+		if (isl_set_plain_is_empty(mustdo) &&
+		    isl_set_plain_is_empty(maydo))
 			break;
 	}
 
@@ -812,10 +1028,13 @@ static __isl_give isl_flow *compute_val_based_dependences(
 done:
 	res->must_no_source = mustdo;
 	res->may_no_source = maydo;
-	isl_access_info_free(acc);
 	return res;
 error:
-	isl_access_info_free(acc);
+	isl_flow_free(res);
+	isl_set_free(mustdo);
+	isl_set_free(maydo);
+	free(must_rel);
+	free(may_rel);
 	return NULL;
 }
 
@@ -839,39 +1058,436 @@ error:
 __isl_give isl_flow *isl_access_info_compute_flow(__isl_take isl_access_info *acc)
 {
 	int j;
-	struct isl_flow *res;
-	isl_dim *dim;
-	isl_map *id;
-	unsigned n_sink;
-	unsigned n_data;
+	struct isl_flow *res = NULL;
 
 	if (!acc)
 		return NULL;
 
-	n_sink = isl_map_dim(acc->sink.map, isl_dim_in);
-	n_data = isl_map_dim(acc->sink.map, isl_dim_out);
-	dim = isl_dim_range(isl_map_get_dim(acc->sink.map));
-	id = isl_map_identity(dim);
-	id = isl_map_insert(id, isl_dim_in, 0, n_sink);
-	acc->sink.map = isl_map_insert(acc->sink.map, isl_dim_in,
-					n_sink, n_data);
-	acc->sink.map = isl_map_intersect(acc->sink.map, id);
+	acc->domain_map = isl_map_domain_map(isl_map_copy(acc->sink.map));
+	acc->sink.map = isl_map_range_map(acc->sink.map);
 	if (!acc->sink.map)
 		goto error;
 
 	if (acc->n_must == 0)
 		res = compute_mem_based_dependences(acc);
-	else
+	else {
+		acc = isl_access_info_sort_sources(acc);
 		res = compute_val_based_dependences(acc);
+	}
+	if (!res)
+		goto error;
 
-	for (j = 0; j < res->n_source; ++j)
-		res->dep[j].map = isl_map_project_out(res->dep[j].map,
-					isl_dim_out, n_sink, n_data);
-	res->must_no_source = isl_set_project_out(res->must_no_source, isl_dim_set, n_sink, n_data);
-	res->may_no_source = isl_set_project_out(res->may_no_source, isl_dim_set, n_sink, n_data);
+	for (j = 0; j < res->n_source; ++j) {
+		res->dep[j].map = isl_map_apply_range(res->dep[j].map,
+					isl_map_copy(acc->domain_map));
+		if (!res->dep[j].map)
+			goto error;
+	}
+	if (!res->must_no_source || !res->may_no_source)
+		goto error;
 
+	isl_access_info_free(acc);
 	return res;
 error:
 	isl_access_info_free(acc);
+	isl_flow_free(res);
+	return NULL;
+}
+
+
+/* Keep track of some information about a schedule for a given
+ * access.  In particular, keep track of which dimensions
+ * have a constant value and of the actual constant values.
+ */
+struct isl_sched_info {
+	int *is_cst;
+	isl_vec *cst;
+};
+
+static void sched_info_free(__isl_take struct isl_sched_info *info)
+{
+	if (!info)
+		return;
+	isl_vec_free(info->cst);
+	free(info->is_cst);
+	free(info);
+}
+
+/* Extract information on the constant dimensions of the schedule
+ * for a given access.  The "map" is of the form
+ *
+ *	[S -> D] -> A
+ *
+ * with S the schedule domain, D the iteration domain and A the data domain.
+ */
+static __isl_give struct isl_sched_info *sched_info_alloc(
+	__isl_keep isl_map *map)
+{
+	isl_ctx *ctx;
+	isl_space *dim;
+	struct isl_sched_info *info;
+	int i, n;
+
+	if (!map)
+		return NULL;
+
+	dim = isl_space_unwrap(isl_space_domain(isl_map_get_space(map)));
+	if (!dim)
+		return NULL;
+	n = isl_space_dim(dim, isl_dim_in);
+	isl_space_free(dim);
+
+	ctx = isl_map_get_ctx(map);
+	info = isl_alloc_type(ctx, struct isl_sched_info);
+	if (!info)
+		return NULL;
+	info->is_cst = isl_alloc_array(ctx, int, n);
+	info->cst = isl_vec_alloc(ctx, n);
+	if (!info->is_cst || !info->cst)
+		goto error;
+
+	for (i = 0; i < n; ++i) {
+		isl_val *v;
+
+		v = isl_map_plain_get_val_if_fixed(map, isl_dim_in, i);
+		if (!v)
+			goto error;
+		info->is_cst[i] = !isl_val_is_nan(v);
+		if (info->is_cst[i])
+			info->cst = isl_vec_set_element_val(info->cst, i, v);
+		else
+			isl_val_free(v);
+	}
+
+	return info;
+error:
+	sched_info_free(info);
 	return NULL;
 }
+
+struct isl_compute_flow_data {
+	isl_union_map *must_source;
+	isl_union_map *may_source;
+	isl_union_map *must_dep;
+	isl_union_map *may_dep;
+	isl_union_map *must_no_source;
+	isl_union_map *may_no_source;
+
+	int count;
+	int must;
+	isl_space *dim;
+	struct isl_sched_info *sink_info;
+	struct isl_sched_info **source_info;
+	isl_access_info *accesses;
+};
+
+static int count_matching_array(__isl_take isl_map *map, void *user)
+{
+	int eq;
+	isl_space *dim;
+	struct isl_compute_flow_data *data;
+
+	data = (struct isl_compute_flow_data *)user;
+
+	dim = isl_space_range(isl_map_get_space(map));
+
+	eq = isl_space_is_equal(dim, data->dim);
+
+	isl_space_free(dim);
+	isl_map_free(map);
+
+	if (eq < 0)
+		return -1;
+	if (eq)
+		data->count++;
+
+	return 0;
+}
+
+static int collect_matching_array(__isl_take isl_map *map, void *user)
+{
+	int eq;
+	isl_space *dim;
+	struct isl_sched_info *info;
+	struct isl_compute_flow_data *data;
+
+	data = (struct isl_compute_flow_data *)user;
+
+	dim = isl_space_range(isl_map_get_space(map));
+
+	eq = isl_space_is_equal(dim, data->dim);
+
+	isl_space_free(dim);
+
+	if (eq < 0)
+		goto error;
+	if (!eq) {
+		isl_map_free(map);
+		return 0;
+	}
+
+	info = sched_info_alloc(map);
+	data->source_info[data->count] = info;
+
+	data->accesses = isl_access_info_add_source(data->accesses,
+						    map, data->must, info);
+
+	data->count++;
+
+	return 0;
+error:
+	isl_map_free(map);
+	return -1;
+}
+
+/* Determine the shared nesting level and the "textual order" of
+ * the given accesses.
+ *
+ * We first determine the minimal schedule dimension for both accesses.
+ *
+ * If among those dimensions, we can find one where both have a fixed
+ * value and if moreover those values are different, then the previous
+ * dimension is the last shared nesting level and the textual order
+ * is determined based on the order of the fixed values.
+ * If no such fixed values can be found, then we set the shared
+ * nesting level to the minimal schedule dimension, with no textual ordering.
+ */
+static int before(void *first, void *second)
+{
+	struct isl_sched_info *info1 = first;
+	struct isl_sched_info *info2 = second;
+	int n1, n2;
+	int i;
+
+	n1 = isl_vec_size(info1->cst);
+	n2 = isl_vec_size(info2->cst);
+
+	if (n2 < n1)
+		n1 = n2;
+
+	for (i = 0; i < n1; ++i) {
+		int r;
+		int cmp;
+
+		if (!info1->is_cst[i])
+			continue;
+		if (!info2->is_cst[i])
+			continue;
+		cmp = isl_vec_cmp_element(info1->cst, info2->cst, i);
+		if (cmp == 0)
+			continue;
+
+		r = 2 * i + (cmp < 0);
+
+		return r;
+	}
+
+	return 2 * n1;
+}
+
+/* Given a sink access, look for all the source accesses that access
+ * the same array and perform dataflow analysis on them using
+ * isl_access_info_compute_flow.
+ */
+static int compute_flow(__isl_take isl_map *map, void *user)
+{
+	int i;
+	isl_ctx *ctx;
+	struct isl_compute_flow_data *data;
+	isl_flow *flow;
+
+	data = (struct isl_compute_flow_data *)user;
+
+	ctx = isl_map_get_ctx(map);
+
+	data->accesses = NULL;
+	data->sink_info = NULL;
+	data->source_info = NULL;
+	data->count = 0;
+	data->dim = isl_space_range(isl_map_get_space(map));
+
+	if (isl_union_map_foreach_map(data->must_source,
+					&count_matching_array, data) < 0)
+		goto error;
+	if (isl_union_map_foreach_map(data->may_source,
+					&count_matching_array, data) < 0)
+		goto error;
+
+	data->sink_info = sched_info_alloc(map);
+	data->source_info = isl_calloc_array(ctx, struct isl_sched_info *,
+					     data->count);
+
+	data->accesses = isl_access_info_alloc(isl_map_copy(map),
+				data->sink_info, &before, data->count);
+	if (!data->sink_info || !data->source_info || !data->accesses)
+		goto error;
+	data->count = 0;
+	data->must = 1;
+	if (isl_union_map_foreach_map(data->must_source,
+					&collect_matching_array, data) < 0)
+		goto error;
+	data->must = 0;
+	if (isl_union_map_foreach_map(data->may_source,
+					&collect_matching_array, data) < 0)
+		goto error;
+
+	flow = isl_access_info_compute_flow(data->accesses);
+	data->accesses = NULL;
+
+	if (!flow)
+		goto error;
+
+	data->must_no_source = isl_union_map_union(data->must_no_source,
+		    isl_union_map_from_map(isl_flow_get_no_source(flow, 1)));
+	data->may_no_source = isl_union_map_union(data->may_no_source,
+		    isl_union_map_from_map(isl_flow_get_no_source(flow, 0)));
+
+	for (i = 0; i < flow->n_source; ++i) {
+		isl_union_map *dep;
+		dep = isl_union_map_from_map(isl_map_copy(flow->dep[i].map));
+		if (flow->dep[i].must)
+			data->must_dep = isl_union_map_union(data->must_dep, dep);
+		else
+			data->may_dep = isl_union_map_union(data->may_dep, dep);
+	}
+
+	isl_flow_free(flow);
+
+	sched_info_free(data->sink_info);
+	if (data->source_info) {
+		for (i = 0; i < data->count; ++i)
+			sched_info_free(data->source_info[i]);
+		free(data->source_info);
+	}
+	isl_space_free(data->dim);
+	isl_map_free(map);
+
+	return 0;
+error:
+	isl_access_info_free(data->accesses);
+	sched_info_free(data->sink_info);
+	if (data->source_info) {
+		for (i = 0; i < data->count; ++i)
+			sched_info_free(data->source_info[i]);
+		free(data->source_info);
+	}
+	isl_space_free(data->dim);
+	isl_map_free(map);
+
+	return -1;
+}
+
+/* Given a collection of "sink" and "source" accesses,
+ * compute for each iteration of a sink access
+ * and for each element accessed by that iteration,
+ * the source access in the list that last accessed the
+ * element accessed by the sink access before this sink access.
+ * Each access is given as a map from the loop iterators
+ * to the array indices.
+ * The result is a relations between source and sink
+ * iterations and a subset of the domain of the sink accesses,
+ * corresponding to those iterations that access an element
+ * not previously accessed.
+ *
+ * We first prepend the schedule dimensions to the domain
+ * of the accesses so that we can easily compare their relative order.
+ * Then we consider each sink access individually in compute_flow.
+ */
+int isl_union_map_compute_flow(__isl_take isl_union_map *sink,
+	__isl_take isl_union_map *must_source,
+	__isl_take isl_union_map *may_source,
+	__isl_take isl_union_map *schedule,
+	__isl_give isl_union_map **must_dep, __isl_give isl_union_map **may_dep,
+	__isl_give isl_union_map **must_no_source,
+	__isl_give isl_union_map **may_no_source)
+{
+	isl_space *dim;
+	isl_union_map *range_map = NULL;
+	struct isl_compute_flow_data data;
+
+	sink = isl_union_map_align_params(sink,
+					    isl_union_map_get_space(must_source));
+	sink = isl_union_map_align_params(sink,
+					    isl_union_map_get_space(may_source));
+	sink = isl_union_map_align_params(sink,
+					    isl_union_map_get_space(schedule));
+	dim = isl_union_map_get_space(sink);
+	must_source = isl_union_map_align_params(must_source, isl_space_copy(dim));
+	may_source = isl_union_map_align_params(may_source, isl_space_copy(dim));
+	schedule = isl_union_map_align_params(schedule, isl_space_copy(dim));
+
+	schedule = isl_union_map_reverse(schedule);
+	range_map = isl_union_map_range_map(schedule);
+	schedule = isl_union_map_reverse(isl_union_map_copy(range_map));
+	sink = isl_union_map_apply_domain(sink, isl_union_map_copy(schedule));
+	must_source = isl_union_map_apply_domain(must_source,
+						isl_union_map_copy(schedule));
+	may_source = isl_union_map_apply_domain(may_source, schedule);
+
+	data.must_source = must_source;
+	data.may_source = may_source;
+	data.must_dep = must_dep ?
+		isl_union_map_empty(isl_space_copy(dim)) : NULL;
+	data.may_dep = may_dep ? isl_union_map_empty(isl_space_copy(dim)) : NULL;
+	data.must_no_source = must_no_source ?
+		isl_union_map_empty(isl_space_copy(dim)) : NULL;
+	data.may_no_source = may_no_source ?
+		isl_union_map_empty(isl_space_copy(dim)) : NULL;
+
+	isl_space_free(dim);
+
+	if (isl_union_map_foreach_map(sink, &compute_flow, &data) < 0)
+		goto error;
+
+	isl_union_map_free(sink);
+	isl_union_map_free(must_source);
+	isl_union_map_free(may_source);
+
+	if (must_dep) {
+		data.must_dep = isl_union_map_apply_domain(data.must_dep,
+					isl_union_map_copy(range_map));
+		data.must_dep = isl_union_map_apply_range(data.must_dep,
+					isl_union_map_copy(range_map));
+		*must_dep = data.must_dep;
+	}
+	if (may_dep) {
+		data.may_dep = isl_union_map_apply_domain(data.may_dep,
+					isl_union_map_copy(range_map));
+		data.may_dep = isl_union_map_apply_range(data.may_dep,
+					isl_union_map_copy(range_map));
+		*may_dep = data.may_dep;
+	}
+	if (must_no_source) {
+		data.must_no_source = isl_union_map_apply_domain(
+			data.must_no_source, isl_union_map_copy(range_map));
+		*must_no_source = data.must_no_source;
+	}
+	if (may_no_source) {
+		data.may_no_source = isl_union_map_apply_domain(
+			data.may_no_source, isl_union_map_copy(range_map));
+		*may_no_source = data.may_no_source;
+	}
+
+	isl_union_map_free(range_map);
+
+	return 0;
+error:
+	isl_union_map_free(range_map);
+	isl_union_map_free(sink);
+	isl_union_map_free(must_source);
+	isl_union_map_free(may_source);
+	isl_union_map_free(data.must_dep);
+	isl_union_map_free(data.may_dep);
+	isl_union_map_free(data.must_no_source);
+	isl_union_map_free(data.may_no_source);
+
+	if (must_dep)
+		*must_dep = NULL;
+	if (may_dep)
+		*may_dep = NULL;
+	if (must_no_source)
+		*must_no_source = NULL;
+	if (may_no_source)
+		*may_no_source = NULL;
+	return -1;
+}