/*
* Copyright 2011 INRIA Saclay
*
- * 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, INRIA Saclay - Ile-de-France,
* Parc Club Orsay Universite, ZAC des vignes, 4 rue Jacques Monod,
#include <isl_tab.h>
#include <isl_dim_map.h>
#include <isl_hmap_map_basic_set.h>
-#include <isl_qsort.h>
+#include <isl_sort.h>
#include <isl_schedule_private.h>
#include <isl_band_private.h>
#include <isl_list_private.h>
#include <isl_options_private.h>
+#include <isl_tarjan.h>
/*
* The scheduling algorithm implemented in this file was inspired by
* indicating whether the corresponding scheduling dimension results
* in zero dependence distances within its band and with respect
* to the proximity edges.
- *
- * index, min_index and on_stack are used during the SCC detection
- * index represents the order in which nodes are visited.
- * min_index is the index of the root of a (sub)component.
- * on_stack indicates whether the node is currently on the stack.
*/
struct isl_sched_node {
isl_space *dim;
int *band;
int *band_id;
int *zero;
-
- /* scc detection */
- int index;
- int min_index;
- int on_stack;
};
static int node_has_dim(const void *entry, const void *val)
enum isl_edge_type {
isl_edge_validity = 0,
+ isl_edge_first = isl_edge_validity,
isl_edge_proximity,
isl_edge_last = isl_edge_proximity
};
* n is the number of nodes
* node is the list of nodes
* maxvar is the maximal number of variables over all nodes
+ * max_row is the allocated number of rows in the schedule
* n_row is the current (maximal) number of linearly independent
* rows in the node schedules
* n_total_row is the current number of rows in the node schedules
* src_scc and dst_scc are the source and sink SCCs of an edge with
* conflicting constraints
*
- * scc, sp, index and stack are used during the detection of SCCs
- * scc is the number of the next SCC
- * stack contains the nodes on the path from the root to the current node
- * sp is the stack pointer
- * index is the index of the last node visited
+ * scc represents the number of components
*/
struct isl_sched_graph {
isl_hmap_map_basic_set *intra_hmap;
struct isl_sched_node *node;
int n;
int maxvar;
+ int max_row;
int n_row;
int *sorted;
int src_scc;
int dst_scc;
- /* scc detection */
int scc;
- int sp;
- int index;
- int *stack;
};
/* Initialize node_table based on the list of nodes.
static struct isl_sched_edge *graph_find_any_edge(struct isl_sched_graph *graph,
struct isl_sched_node *src, struct isl_sched_node *dst)
{
- int i;
+ enum isl_edge_type i;
struct isl_sched_edge *edge;
- for (i = 0; i <= isl_edge_last; ++i) {
+ for (i = isl_edge_first; i <= isl_edge_last; ++i) {
edge = graph_find_edge(graph, i, src, dst);
if (edge)
return edge;
struct isl_sched_edge *edge)
{
isl_ctx *ctx = isl_map_get_ctx(edge->map);
- int i;
+ enum isl_edge_type i;
- for (i = 0; i <= isl_edge_last; ++i) {
+ for (i = isl_edge_first; i <= isl_edge_last; ++i) {
struct isl_hash_table_entry *entry;
entry = graph_find_edge_entry(graph, i, edge->src, edge->dst);
static int graph_has_any_edge(struct isl_sched_graph *graph,
struct isl_sched_node *src, struct isl_sched_node *dst)
{
- int i;
+ enum isl_edge_type i;
int r;
- for (i = 0; i <= isl_edge_last; ++i) {
+ for (i = isl_edge_first; i <= isl_edge_last; ++i) {
r = graph_has_edge(graph, i, src, dst);
if (r < 0 || r)
return r;
graph->node = isl_calloc_array(ctx, struct isl_sched_node, graph->n);
graph->sorted = isl_calloc_array(ctx, int, graph->n);
graph->region = isl_alloc_array(ctx, struct isl_region, graph->n);
- graph->stack = isl_alloc_array(ctx, int, graph->n);
graph->edge = isl_calloc_array(ctx,
struct isl_sched_edge, graph->n_edge);
graph->intra_hmap = isl_hmap_map_basic_set_alloc(ctx, 2 * n_edge);
graph->inter_hmap = isl_hmap_map_basic_set_alloc(ctx, 2 * n_edge);
- if (!graph->node || !graph->region || !graph->stack || !graph->edge ||
- !graph->sorted)
+ if (!graph->node || !graph->region || !graph->edge || !graph->sorted)
return -1;
for(i = 0; i < graph->n; ++i)
isl_map_free(graph->edge[i].map);
free(graph->edge);
free(graph->region);
- free(graph->stack);
for (i = 0; i <= isl_edge_last; ++i)
isl_hash_table_free(ctx, graph->edge_table[i]);
isl_hash_table_free(ctx, graph->node_table);
isl_basic_set_free(graph->lp);
}
+/* For each "set" on which this function is called, increment
+ * graph->n by one and update graph->maxvar.
+ */
+static int init_n_maxvar(__isl_take isl_set *set, void *user)
+{
+ struct isl_sched_graph *graph = user;
+ int nvar = isl_set_dim(set, isl_dim_set);
+
+ graph->n++;
+ if (nvar > graph->maxvar)
+ graph->maxvar = nvar;
+
+ isl_set_free(set);
+
+ return 0;
+}
+
+/* Compute the number of rows that should be allocated for the schedule.
+ * The graph can be split at most "n - 1" times, there can be at most
+ * two rows for each dimension in the iteration domains (in particular,
+ * we usually have one row, but it may be split by split_scaled),
+ * and there can be one extra row for ordering the statements.
+ * Note that if we have actually split "n - 1" times, then no ordering
+ * is needed, so in principle we could use "graph->n + 2 * graph->maxvar - 1".
+ */
+static int compute_max_row(struct isl_sched_graph *graph,
+ __isl_keep isl_union_set *domain)
+{
+ graph->n = 0;
+ graph->maxvar = 0;
+ if (isl_union_set_foreach_set(domain, &init_n_maxvar, graph) < 0)
+ return -1;
+ graph->max_row = graph->n + 2 * graph->maxvar;
+
+ return 0;
+}
+
/* Add a new node to the graph representing the given set.
*/
static int extract_node(__isl_take isl_set *set, void *user)
graph->node[graph->n].nparam = nparam;
graph->node[graph->n].sched = sched;
graph->node[graph->n].sched_map = NULL;
- band = isl_alloc_array(ctx, int, graph->n_edge + nvar);
+ band = isl_alloc_array(ctx, int, graph->max_row);
graph->node[graph->n].band = band;
- band_id = isl_calloc_array(ctx, int, graph->n_edge + nvar);
+ band_id = isl_calloc_array(ctx, int, graph->max_row);
graph->node[graph->n].band_id = band_id;
- zero = isl_calloc_array(ctx, int, graph->n_edge + nvar);
+ zero = isl_calloc_array(ctx, int, graph->max_row);
graph->node[graph->n].zero = zero;
graph->n++;
return graph_edge_table_add(ctx, graph, data->type, edge);
}
-/* Check whether there is a validity dependence from src to dst,
- * forcing dst to follow src (if weak is not set).
- * If weak is set, then check if there is any dependence from src to dst.
+/* Check whether there is any dependence from node[j] to node[i]
+ * or from node[i] to node[j].
*/
-static int node_follows(struct isl_sched_graph *graph,
- struct isl_sched_node *dst, struct isl_sched_node *src, int weak)
+static int node_follows_weak(int i, int j, void *user)
{
- if (weak)
- return graph_has_any_edge(graph, src, dst);
- else
- return graph_has_validity_edge(graph, src, dst);
+ int f;
+ struct isl_sched_graph *graph = user;
+
+ f = graph_has_any_edge(graph, &graph->node[j], &graph->node[i]);
+ if (f < 0 || f)
+ return f;
+ return graph_has_any_edge(graph, &graph->node[i], &graph->node[j]);
+}
+
+/* Check whether there is a validity dependence from node[j] to node[i],
+ * forcing node[i] to follow node[j].
+ */
+static int node_follows_strong(int i, int j, void *user)
+{
+ struct isl_sched_graph *graph = user;
+
+ return graph_has_validity_edge(graph, &graph->node[j], &graph->node[i]);
}
-/* Perform Tarjan's algorithm for computing the strongly connected components
+/* Use Tarjan's algorithm for computing the strongly connected components
* in the dependence graph (only validity edges).
* If weak is set, we consider the graph to be undirected and
* we effectively compute the (weakly) connected components.
* Additionally, we also consider other edges when weak is set.
*/
-static int detect_sccs_tarjan(struct isl_sched_graph *g, int i, int weak)
+static int detect_ccs(isl_ctx *ctx, struct isl_sched_graph *graph, int weak)
{
- int j;
-
- g->node[i].index = g->index;
- g->node[i].min_index = g->index;
- g->node[i].on_stack = 1;
- g->index++;
- g->stack[g->sp++] = i;
+ int i, n;
+ struct isl_tarjan_graph *g = NULL;
- for (j = g->n - 1; j >= 0; --j) {
- int f;
+ g = isl_tarjan_graph_init(ctx, graph->n,
+ weak ? &node_follows_weak : &node_follows_strong, graph);
+ if (!g)
+ return -1;
- if (j == i)
- continue;
- if (g->node[j].index >= 0 &&
- (!g->node[j].on_stack ||
- g->node[j].index > g->node[i].min_index))
- continue;
-
- f = node_follows(g, &g->node[i], &g->node[j], weak);
- if (f < 0)
- return -1;
- if (!f && weak) {
- f = node_follows(g, &g->node[j], &g->node[i], weak);
- if (f < 0)
- return -1;
+ graph->scc = 0;
+ i = 0;
+ n = graph->n;
+ while (n) {
+ while (g->order[i] != -1) {
+ graph->node[g->order[i]].scc = graph->scc;
+ --n;
+ ++i;
}
- if (!f)
- continue;
- if (g->node[j].index < 0) {
- detect_sccs_tarjan(g, j, weak);
- if (g->node[j].min_index < g->node[i].min_index)
- g->node[i].min_index = g->node[j].min_index;
- } else if (g->node[j].index < g->node[i].min_index)
- g->node[i].min_index = g->node[j].index;
+ ++i;
+ graph->scc++;
}
- if (g->node[i].index != g->node[i].min_index)
- return 0;
-
- do {
- j = g->stack[--g->sp];
- g->node[j].on_stack = 0;
- g->node[j].scc = g->scc;
- } while (j != i);
- g->scc++;
-
- return 0;
-}
-
-static int detect_ccs(struct isl_sched_graph *graph, int weak)
-{
- int i;
-
- graph->index = 0;
- graph->sp = 0;
- graph->scc = 0;
- for (i = graph->n - 1; i >= 0; --i)
- graph->node[i].index = -1;
-
- for (i = graph->n - 1; i >= 0; --i) {
- if (graph->node[i].index >= 0)
- continue;
- if (detect_sccs_tarjan(graph, i, weak) < 0)
- return -1;
- }
+ isl_tarjan_graph_free(g);
return 0;
}
/* Apply Tarjan's algorithm to detect the strongly connected components
* in the dependence graph.
*/
-static int detect_sccs(struct isl_sched_graph *graph)
+static int detect_sccs(isl_ctx *ctx, struct isl_sched_graph *graph)
{
- return detect_ccs(graph, 0);
+ return detect_ccs(ctx, graph, 0);
}
/* Apply Tarjan's algorithm to detect the (weakly) connected components
* in the dependence graph.
*/
-static int detect_wccs(struct isl_sched_graph *graph)
+static int detect_wccs(isl_ctx *ctx, struct isl_sched_graph *graph)
{
- return detect_ccs(graph, 1);
+ return detect_ccs(ctx, graph, 1);
}
static int cmp_scc(const void *a, const void *b, void *data)
/* Sort the elements of graph->sorted according to the corresponding SCCs.
*/
-static void sort_sccs(struct isl_sched_graph *graph)
+static int sort_sccs(struct isl_sched_graph *graph)
{
- isl_quicksort(graph->sorted, graph->n, sizeof(int), &cmp_scc, graph);
+ return isl_sort(graph->sorted, graph->n, sizeof(int), &cmp_scc, graph);
}
/* Given a dependence relation R from a node to itself,
if (sol->size == 0)
isl_die(sol->ctx, isl_error_internal,
"no solution found", goto error);
+ if (graph->n_total_row >= graph->max_row)
+ isl_die(sol->ctx, isl_error_internal,
+ "too many schedule rows", goto error);
if (check_zero)
zero = isl_int_is_zero(sol->el[1]) &&
if (graph->n_edge == 0)
return 0;
- if (detect_sccs(graph) < 0)
+ if (detect_sccs(ctx, graph) < 0)
return -1;
+ if (graph->n_total_row >= graph->max_row)
+ isl_die(ctx, isl_error_internal,
+ "too many schedule rows", return -1);
+
for (i = 0; i < graph->n; ++i) {
struct isl_sched_node *node = &graph->node[i];
int row = isl_mat_rows(node->sched);
int r, b;
int *band_end, *band_id, *zero;
+ sched->node[i].sched =
+ node_extract_schedule_multi_aff(&graph->node[i]);
+ if (!sched->node[i].sched)
+ goto error;
+
+ sched->node[i].n_band = graph->n_band;
+ if (graph->n_band == 0)
+ continue;
+
band_end = isl_alloc_array(ctx, int, graph->n_band);
band_id = isl_alloc_array(ctx, int, graph->n_band);
zero = isl_alloc_array(ctx, int, graph->n_total_row);
- sched->node[i].sched =
- node_extract_schedule_multi_aff(&graph->node[i]);
sched->node[i].band_end = band_end;
sched->node[i].band_id = band_id;
sched->node[i].zero = zero;
int (*edge_pred)(struct isl_sched_edge *edge, int data), int data)
{
int i;
- int t;
+ enum isl_edge_type t;
dst->n_edge = 0;
for (i = 0; i < src->n_edge; ++i) {
dst->edge[dst->n_edge].proximity = edge->proximity;
dst->n_edge++;
- for (t = 0; t <= isl_edge_last; ++t) {
+ for (t = isl_edge_first; t <= isl_edge_last; ++t) {
if (edge !=
graph_find_edge(src, t, edge->src, edge->dst))
continue;
src->n++;
}
+ dst->max_row = src->max_row;
dst->n_total_row = src->n_total_row;
dst->n_band = src->n_band;
if (copy_edges(ctx, &split, graph, edge_pred, data) < 0)
goto error;
split.n_row = graph->n_row;
+ split.max_row = graph->max_row;
split.n_total_row = graph->n_total_row;
split.n_band = graph->n_band;
split.band_start = graph->band_start;
int n_band, orig_band;
int drop;
+ if (graph->n_total_row >= graph->max_row)
+ isl_die(ctx, isl_error_internal,
+ "too many schedule rows", return -1);
+
drop = graph->n_total_row - graph->band_start;
graph->n_total_row -= drop;
graph->n_row -= drop;
if (graph->n <= 1)
return 0;
+ if (graph->n_total_row >= graph->max_row)
+ isl_die(ctx, isl_error_internal,
+ "too many schedule rows", return -1);
+
isl_int_init(gcd);
isl_int_init(gcd_i);
return -1;
}
+static int compute_component_schedule(isl_ctx *ctx,
+ struct isl_sched_graph *graph);
+
+/* Is the schedule row "sol" trivial on node "node"?
+ * That is, is the solution zero on the dimensions orthogonal to
+ * the previously found solutions?
+ * Each coefficient is represented as the difference between
+ * two non-negative values in "sol". The coefficient is then
+ * zero if those two values are equal to each other.
+ */
+static int is_trivial(struct isl_sched_node *node, __isl_keep isl_vec *sol)
+{
+ int i;
+ int pos;
+ int len;
+
+ pos = 1 + node->start + 1 + 2 * (node->nparam + node->rank);
+ len = 2 * (node->nvar - node->rank);
+
+ if (len == 0)
+ return 0;
+
+ for (i = 0; i < len; i += 2)
+ if (isl_int_ne(sol->el[pos + i], sol->el[pos + i + 1]))
+ return 0;
+
+ return 1;
+}
+
+/* Is the schedule row "sol" trivial on any node where it should
+ * not be trivial?
+ */
+static int is_any_trivial(struct isl_sched_graph *graph,
+ __isl_keep isl_vec *sol)
+{
+ int i;
+
+ for (i = 0; i < graph->n; ++i) {
+ struct isl_sched_node *node = &graph->node[i];
+
+ if (!needs_row(graph, node))
+ continue;
+ if (is_trivial(node, sol))
+ return 1;
+ }
+
+ return 0;
+}
+
/* Construct a schedule row for each node such that as many dependences
* as possible are carried and then continue with the next band.
+ *
+ * If the computed schedule row turns out to be trivial on one or
+ * more nodes where it should not be trivial, then we throw it away
+ * and try again on each component separately.
*/
static int carry_dependences(isl_ctx *ctx, struct isl_sched_graph *graph)
{
"unable to carry dependences", return -1);
}
+ if (is_any_trivial(graph, sol)) {
+ isl_vec_free(sol);
+ if (graph->scc > 1)
+ return compute_component_schedule(ctx, graph);
+ isl_die(ctx, isl_error_unknown,
+ "unable to construct non-trivial solution", return -1);
+ }
+
if (update_schedule(graph, sol, 0, 0) < 0)
return -1;
{
int force_zero = 0;
- if (detect_sccs(graph) < 0)
+ if (detect_sccs(ctx, graph) < 0)
+ return -1;
+ if (sort_sccs(graph) < 0)
return -1;
- sort_sccs(graph);
if (compute_maxvar(graph) < 0)
return -1;
/* Add a row to the schedules that separates the SCCs and move
* to the next band.
*/
-static int split_on_scc(struct isl_sched_graph *graph)
+static int split_on_scc(isl_ctx *ctx, struct isl_sched_graph *graph)
{
int i;
+ if (graph->n_total_row >= graph->max_row)
+ isl_die(ctx, isl_error_internal,
+ "too many schedule rows", return -1);
+
for (i = 0; i < graph->n; ++i) {
struct isl_sched_node *node = &graph->node[i];
int row = isl_mat_rows(node->sched);
if (ctx->opt->schedule_fuse == ISL_SCHEDULE_FUSE_MIN ||
ctx->opt->schedule_separate_components)
- split_on_scc(graph);
+ if (split_on_scc(ctx, graph) < 0)
+ return -1;
n_total_row = 0;
orig_total_row = graph->n_total_row;
static int compute_schedule(isl_ctx *ctx, struct isl_sched_graph *graph)
{
if (ctx->opt->schedule_fuse == ISL_SCHEDULE_FUSE_MIN) {
- if (detect_sccs(graph) < 0)
+ if (detect_sccs(ctx, graph) < 0)
return -1;
} else {
- if (detect_wccs(graph) < 0)
+ if (detect_wccs(ctx, graph) < 0)
return -1;
}
if (graph_alloc(ctx, &graph, graph.n,
isl_union_map_n_map(validity) + isl_union_map_n_map(proximity)) < 0)
goto error;
+ if (compute_max_row(&graph, domain) < 0)
+ goto error;
graph.root = 1;
graph.n = 0;
if (isl_union_set_foreach_set(domain, &extract_node, &graph) < 0)
projects / platform / upstream / isl.git / blobdiff