/* Linear Loop transforms
- Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
Contributed by Daniel Berlin <dberlin@dberlin.org>.
This file is part of GCC.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
-#include "errors.h"
#include "ggc.h"
#include "tree.h"
#include "target.h"
#include "tree-data-ref.h"
#include "tree-scalar-evolution.h"
#include "tree-pass.h"
-#include "varray.h"
#include "lambda.h"
/* Linear loop transforms include any composition of interchange,
transform matrix for locality purposes.
TODO: Completion of partial transforms. */
-/* Gather statistics for loop interchange. LOOP_NUMBER is a relative
- index in the considered loop nest. The first loop in the
- considered loop nest is FIRST_LOOP, and consequently the index of
- the considered loop is obtained by FIRST_LOOP + LOOP_NUMBER.
+/* Gather statistics for loop interchange. LOOP is the loop being
+ considered. The first loop in the considered loop nest is
+ FIRST_LOOP, and consequently, the index of the considered loop is
+ obtained by LOOP->DEPTH - FIRST_LOOP->DEPTH
Initializes:
- DEPENDENCE_STEPS the sum of all the data dependence distances
- carried by loop LOOP_NUMBER,
+ carried by loop LOOP,
- NB_DEPS_NOT_CARRIED_BY_LOOP the number of dependence relations
- for which the loop LOOP_NUMBER is not carrying any dependence,
+ for which the loop LOOP is not carrying any dependence,
- - ACCESS_STRIDES the sum of all the strides in LOOP_NUMBER.
+ - ACCESS_STRIDES the sum of all the strides in LOOP.
Example: for the following loop,
DEPENDENCE_STEPS = 3000
NB_DEPS_NOT_CARRIED_BY_LOOP = 7
ACCESS_STRIDES = 8010
- */
+*/
static void
-gather_interchange_stats (varray_type dependence_relations,
- varray_type datarefs,
- unsigned int loop_number,
- unsigned int first_loop,
+gather_interchange_stats (VEC (ddr_p, heap) *dependence_relations,
+ VEC (data_reference_p, heap) *datarefs,
+ struct loop *loop,
+ struct loop *first_loop,
unsigned int *dependence_steps,
unsigned int *nb_deps_not_carried_by_loop,
unsigned int *access_strides)
{
- unsigned int i;
+ unsigned int i, j;
+ struct data_dependence_relation *ddr;
+ struct data_reference *dr;
*dependence_steps = 0;
*nb_deps_not_carried_by_loop = 0;
*access_strides = 0;
- for (i = 0; i < VARRAY_ACTIVE_SIZE (dependence_relations); i++)
+ for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
{
- int dist;
- struct data_dependence_relation *ddr =
- (struct data_dependence_relation *)
- VARRAY_GENERIC_PTR (dependence_relations, i);
-
- /* Compute the dependence strides. */
+ /* If we don't know anything about this dependence, or the distance
+ vector is NULL, or there is no dependence, then there is no reuse of
+ data. */
+ if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know
+ || DDR_ARE_DEPENDENT (ddr) == chrec_known
+ || DDR_NUM_DIST_VECTS (ddr) == 0)
+ continue;
- if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
+ for (j = 0; j < DDR_NUM_DIST_VECTS (ddr); j++)
{
- (*dependence_steps) += 0;
- continue;
- }
+ int dist = DDR_DIST_VECT (ddr, j)[loop->depth - first_loop->depth];
- /* When we know that there is no dependence, we know that there
- is no reuse of the data. */
- if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
- {
- (*dependence_steps) += 0;
- continue;
- }
+ if (dist == 0)
+ (*nb_deps_not_carried_by_loop) += 1;
+
+ else if (dist < 0)
+ (*dependence_steps) += -dist;
- dist = DDR_DIST_VECT (ddr)[loop_number];
- if (dist == 0)
- (*nb_deps_not_carried_by_loop) += 1;
- else if (dist < 0)
- (*dependence_steps) += -dist;
- else
- (*dependence_steps) += dist;
+ else
+ (*dependence_steps) += dist;
+ }
}
/* Compute the access strides. */
- for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++)
+ for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
{
unsigned int it;
- struct data_reference *dr = VARRAY_GENERIC_PTR (datarefs, i);
tree stmt = DR_STMT (dr);
struct loop *stmt_loop = loop_containing_stmt (stmt);
- struct loop *inner_loop = current_loops->parray[first_loop + 1];
-
- if (!flow_loop_nested_p (inner_loop, stmt_loop)
- && inner_loop->num != stmt_loop->num)
+ struct loop *inner_loop = first_loop->inner;
+
+ if (inner_loop != stmt_loop
+ && !flow_loop_nested_p (inner_loop, stmt_loop))
continue;
-
for (it = 0; it < DR_NUM_DIMENSIONS (dr); it++)
{
tree chrec = DR_ACCESS_FN (dr, it);
tree tstride = evolution_part_in_loop_num
- (chrec, first_loop + loop_number);
+ (chrec, loop->num);
if (tstride == NULL_TREE
|| TREE_CODE (tstride) != INTEGER_CST)
}
}
-/* Apply to TRANS any loop interchange that minimize inner loop steps.
+/* Attempt to apply interchange transformations to TRANS to maximize the
+ spatial and temporal locality of the loop.
Returns the new transform matrix. The smaller the reuse vector
distances in the inner loops, the fewer the cache misses.
FIRST_LOOP is the loop->num of the first loop in the analyzed loop
static lambda_trans_matrix
try_interchange_loops (lambda_trans_matrix trans,
unsigned int depth,
- varray_type dependence_relations,
- varray_type datarefs,
- unsigned int first_loop)
+ VEC (ddr_p, heap) *dependence_relations,
+ VEC (data_reference_p, heap) *datarefs,
+ struct loop *first_loop)
{
- unsigned int loop_i, loop_j;
+ struct loop *loop_i;
+ struct loop *loop_j;
unsigned int dependence_steps_i, dependence_steps_j;
unsigned int access_strides_i, access_strides_j;
unsigned int nb_deps_not_carried_by_i, nb_deps_not_carried_by_j;
struct data_dependence_relation *ddr;
+ if (VEC_length (ddr_p, dependence_relations) == 0)
+ return trans;
+
/* When there is an unknown relation in the dependence_relations, we
know that it is no worth looking at this loop nest: give up. */
- ddr = (struct data_dependence_relation *)
- VARRAY_GENERIC_PTR (dependence_relations, 0);
+ ddr = VEC_index (ddr_p, dependence_relations, 0);
if (ddr == NULL || DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
return trans;
/* LOOP_I is always the outer loop. */
- for (loop_j = 1; loop_j < depth; loop_j++)
- for (loop_i = 0; loop_i < loop_j; loop_i++)
+ for (loop_j = first_loop->inner;
+ loop_j;
+ loop_j = loop_j->inner)
+ for (loop_i = first_loop;
+ loop_i->depth < loop_j->depth;
+ loop_i = loop_i->inner)
{
gather_interchange_stats (dependence_relations, datarefs,
loop_i, first_loop,
|| nb_deps_not_carried_by_i > nb_deps_not_carried_by_j
|| access_strides_i < access_strides_j)
{
- lambda_matrix_row_exchange (LTM_MATRIX (trans), loop_i, loop_j);
+ lambda_matrix_row_exchange (LTM_MATRIX (trans),
+ loop_i->depth - first_loop->depth,
+ loop_j->depth - first_loop->depth);
/* Validate the resulting matrix. When the transformation
is not valid, reverse to the previous transformation. */
if (!lambda_transform_legal_p (trans, depth, dependence_relations))
- lambda_matrix_row_exchange (LTM_MATRIX (trans), loop_i, loop_j);
+ lambda_matrix_row_exchange (LTM_MATRIX (trans),
+ loop_i->depth - first_loop->depth,
+ loop_j->depth - first_loop->depth);
}
}
return trans;
}
-/* Perform a set of linear transforms on LOOPS. */
+/* Perform a set of linear transforms on loops. */
void
-linear_transform_loops (struct loops *loops)
+linear_transform_loops (void)
{
- unsigned int i;
-
- for (i = 1; i < loops->num; i++)
+ bool modified = false;
+ loop_iterator li;
+ VEC(tree,heap) *oldivs = NULL;
+ VEC(tree,heap) *invariants = NULL;
+ struct loop *loop_nest;
+
+ FOR_EACH_LOOP (li, loop_nest, 0)
{
unsigned int depth = 0;
- varray_type datarefs;
- varray_type dependence_relations;
- struct loop *loop_nest = loops->parray[i];
+ VEC (ddr_p, heap) *dependence_relations;
+ VEC (data_reference_p, heap) *datarefs;
struct loop *temp;
- VEC (tree) *oldivs;
- VEC (tree) *invariants;
lambda_loopnest before, after;
lambda_trans_matrix trans;
bool problem = false;
- bool need_perfect_nest = false;
/* If it's not a loop nest, we don't want it.
We also don't handle sibling loops properly,
which are loops of the following form:
{
...
}
- for (j = 0; j < 50; j++)
+ for (j = 0; j < 50; j++)
{
...
}
} */
- if (!loop_nest->inner)
+ if (!loop_nest->inner || !single_exit (loop_nest))
continue;
+ VEC_truncate (tree, oldivs, 0);
+ VEC_truncate (tree, invariants, 0);
depth = 1;
for (temp = loop_nest->inner; temp; temp = temp->inner)
{
- flow_loop_scan (temp, LOOP_ALL);
/* If we have a sibling loop or multiple exit edges, jump ship. */
- if (temp->next || temp->num_exits != 1)
+ if (temp->next || !single_exit (temp))
{
problem = true;
break;
/* Analyze data references and dependence relations using scev. */
- VARRAY_GENERIC_PTR_INIT (datarefs, 10, "datarefs");
- VARRAY_GENERIC_PTR_INIT (dependence_relations, 10,
- "dependence_relations");
-
-
- compute_data_dependences_for_loop (depth, loop_nest,
- &datarefs, &dependence_relations);
+ datarefs = VEC_alloc (data_reference_p, heap, 10);
+ dependence_relations = VEC_alloc (ddr_p, heap, 10 * 10);
+ compute_data_dependences_for_loop (loop_nest, true, &datarefs,
+ &dependence_relations);
+
if (dump_file && (dump_flags & TDF_DETAILS))
- {
- unsigned int j;
- for (j = 0; j < VARRAY_ACTIVE_SIZE (dependence_relations); j++)
- {
- struct data_dependence_relation *ddr =
- (struct data_dependence_relation *)
- VARRAY_GENERIC_PTR (dependence_relations, j);
-
- if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
- {
- fprintf (dump_file, "DISTANCE_V (");
- print_lambda_vector (dump_file, DDR_DIST_VECT (ddr),
- loops->num);
- fprintf (dump_file, ")\n");
- fprintf (dump_file, "DIRECTION_V (");
- print_lambda_vector (dump_file, DDR_DIR_VECT (ddr),
- loops->num);
- fprintf (dump_file, ")\n");
- }
- }
- fprintf (dump_file, "\n\n");
- }
+ dump_ddrs (dump_file, dependence_relations);
+
/* Build the transformation matrix. */
trans = lambda_trans_matrix_new (depth, depth);
lambda_matrix_id (LTM_MATRIX (trans), depth);
trans = try_interchange_loops (trans, depth, dependence_relations,
- datarefs, loop_nest->num);
+ datarefs, loop_nest);
if (lambda_trans_matrix_id_p (trans))
{
if (dump_file)
fprintf (dump_file, "Won't transform loop. Optimal transform is the identity transform\n");
- continue;
+ goto free_and_continue;
}
/* Check whether the transformation is legal. */
{
if (dump_file)
fprintf (dump_file, "Can't transform loop, transform is illegal:\n");
- continue;
+ goto free_and_continue;
}
- if (!perfect_nest_p (loop_nest))
- need_perfect_nest = true;
- before = gcc_loopnest_to_lambda_loopnest (loops,
- loop_nest, &oldivs,
- &invariants,
- need_perfect_nest);
+
+ before = gcc_loopnest_to_lambda_loopnest (loop_nest, &oldivs,
+ &invariants);
+
if (!before)
- continue;
-
+ goto free_and_continue;
+
if (dump_file)
{
fprintf (dump_file, "Before:\n");
}
after = lambda_loopnest_transform (before, trans);
+
if (dump_file)
{
fprintf (dump_file, "After:\n");
print_lambda_loopnest (dump_file, after, 'u');
}
+
lambda_loopnest_to_gcc_loopnest (loop_nest, oldivs, invariants,
after, trans);
- oldivs = NULL;
- invariants = NULL;
+ modified = true;
+
+ if (dump_file)
+ fprintf (dump_file, "Successfully transformed loop.\n");
+
+ free_and_continue:
free_dependence_relations (dependence_relations);
free_data_refs (datarefs);
}
- rewrite_into_loop_closed_ssa ();
- free_df ();
+
+ VEC_free (tree, heap, oldivs);
+ VEC_free (tree, heap, invariants);
+ scev_reset ();
+
+ if (modified)
+ rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa_full_phi);
}
OSDN Git Service
