lambda_trans_matrix
lambda_trans_matrix_inverse (lambda_trans_matrix mat)
{
lambda_trans_matrix inverse;
int determinant;
inverse = lambda_trans_matrix_new (LTM_ROWSIZE (mat), LTM_COLSIZE (mat));
determinant = lambda_matrix_inverse (LTM_MATRIX (mat), LTM_MATRIX (inverse),
LTM_ROWSIZE (mat));
LTM_DENOMINATOR (inverse) = determinant;
return inverse;
}
bool
lambda_trans_matrix_id_p (lambda_trans_matrix mat)
{
if (LTM_ROWSIZE (mat) != LTM_COLSIZE (mat))
return false;
return lambda_matrix_id_p (LTM_MATRIX (mat), LTM_ROWSIZE (mat));
}
lambda_trans_matrix
lambda_trans_matrix_new (int colsize, int rowsize)
{
lambda_trans_matrix ret;
ret = GGC_NEW (struct lambda_trans_matrix_s);
LTM_MATRIX (ret) = lambda_matrix_new (rowsize, colsize);
LTM_ROWSIZE (ret) = rowsize;
LTM_COLSIZE (ret) = colsize;
LTM_DENOMINATOR (ret) = 1;
return ret;
}
lambda_trans_matrix
lambda_trans_matrix_new (int colsize, int rowsize)
{
lambda_trans_matrix ret;
ret = ggc_alloc (sizeof (*ret));
LTM_MATRIX (ret) = lambda_matrix_new (rowsize, colsize);
LTM_ROWSIZE (ret) = rowsize;
LTM_COLSIZE (ret) = colsize;
LTM_DENOMINATOR (ret) = 1;
return ret;
}
void
print_lambda_trans_matrix (FILE *outfile, lambda_trans_matrix mat)
{
print_lambda_matrix (outfile, LTM_MATRIX (mat), LTM_ROWSIZE (mat),
LTM_COLSIZE (mat));
}
void
linear_transform_loops (struct loops *loops)
{
unsigned int i;
compute_immediate_uses (TDFA_USE_OPS | TDFA_USE_VOPS, NULL);
for (i = 1; i < loops->num; i++)
{
unsigned int depth = 0;
varray_type datarefs;
varray_type dependence_relations;
struct loop *loop_nest = loops->parray[i];
struct loop *temp;
VEC (tree) *oldivs = NULL;
VEC (tree) *invariants = NULL;
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 (i = 0; i < 50; i++)
{
for (j = 0; j < 50; j++)
{
...
}
for (j = 0; j < 50; j++)
{
...
}
} */
if (!loop_nest->inner)
continue;
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)
{
problem = true;
break;
}
depth ++;
}
if (problem)
continue;
/* 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);
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),
DDR_SIZE_VECT (ddr));
fprintf (dump_file, ")\n");
fprintf (dump_file, "DIRECTION_V (");
print_lambda_vector (dump_file, DDR_DIR_VECT (ddr),
DDR_SIZE_VECT (ddr));
fprintf (dump_file, ")\n");
}
}
fprintf (dump_file, "\n\n");
}
/* 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);
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;
}
/* Check whether the transformation is legal. */
if (!lambda_transform_legal_p (trans, depth, dependence_relations))
{
if (dump_file)
fprintf (dump_file, "Can't transform loop, transform is illegal:\n");
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);
if (!before)
continue;
if (dump_file)
{
fprintf (dump_file, "Before:\n");
print_lambda_loopnest (dump_file, before, 'i');
}
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);
if (dump_file)
fprintf (dump_file, "Successfully transformed loop.\n");
oldivs = NULL;
invariants = NULL;
free_dependence_relations (dependence_relations);
free_data_refs (datarefs);
}
free_df ();
scev_reset ();
rewrite_into_loop_closed_ssa ();
#ifdef ENABLE_CHECKING
verify_loop_closed_ssa ();
#endif
}
static lambda_trans_matrix
try_interchange_loops (lambda_trans_matrix trans,
unsigned int depth,
varray_type dependence_relations,
varray_type datarefs,
struct loop *first_loop)
{
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;
/* 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);
if (ddr == NULL || DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
return trans;
/* LOOP_I is always the outer loop. */
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,
&dependence_steps_i,
&nb_deps_not_carried_by_i,
&access_strides_i);
gather_interchange_stats (dependence_relations, datarefs,
loop_j, first_loop,
&dependence_steps_j,
&nb_deps_not_carried_by_j,
&access_strides_j);
/* Heuristics for loop interchange profitability:
1. (spatial locality) Inner loops should have smallest
dependence steps.
2. (spatial locality) Inner loops should contain more
dependence relations not carried by the loop.
3. (temporal locality) Inner loops should have smallest
array access strides.
*/
if (dependence_steps_i < dependence_steps_j
|| 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->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->depth - first_loop->depth,
loop_j->depth - first_loop->depth);
}
}
return trans;
}
