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graphite-interchange.c (build_partial_difference): New. 

2009-11-04  Konrad Trifunovic  <konrad.trifunovic@inria.fr>

        * graphite-interchange.c (build_partial_difference): New.
        (memory_stride_in_loop): Refactored the computation of
        equality constraints into build_partial_difference function.
        Added support for debugging stride computations.

From-SVN: r154634
This commit is contained in:
Konrad Trifunovic 2009-11-25 06:29:01 +01:00 committed by Sebastian Pop
parent 8c54631db7
commit 2bc529bf7d
2 changed files with 103 additions and 38 deletions
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7
gcc/ChangeLog.graphite
View File

@ -1,3 +1,10 @@
2009-11-04 Konrad Trifunovic <konrad.trifunovic@inria.fr>
* graphite-interchange.c (build_partial_difference): New.
(memory_stride_in_loop): Refactored the computation of
equality constraints into build_partial_difference function.
Added support for debugging stride computations.
2009-11-03 Sebastian Pop <sebastian.pop@amd.com>
* graphite-clast-to-gimple.c (gloog): Free if_region,

134
gcc/graphite-interchange.c
View File

@ -104,6 +104,94 @@ build_linearized_memory_access (ppl_dimension_type offset, poly_dr_p pdr)
return res;
}
/* Builds a partial difference equations and inserts them
into pointset powerset polyhedron P. Polyhedron is assumed
to have the format: T|I|T'|I'|G|S|S'|l1|l2.
TIME_DEPTH is the time dimension w.r.t. which we are
differentiating.
OFFSET represents the number of dimensions between
columns t_{time_depth} and t'_{time_depth}.
DIM_SCTR is the number of scattering dimensions. It is
essentially the dimensionality of the T vector.
The following equations are inserted into the polyhedron P:
| t_1 = t_1'
| ...
| t_{time_depth-1} = t'_{time_depth-1}
| t_{time_depth} = t'_{time_depth} + 1
| t_{time_depth+1} = t'_{time_depth + 1}
| ...
| t_{dim_sctr} = t'_{dim_sctr}. */
static void
build_partial_difference (ppl_Pointset_Powerset_C_Polyhedron_t *p,
ppl_dimension_type time_depth,
ppl_dimension_type offset,
ppl_dimension_type dim_sctr)
{
ppl_Constraint_t new_cstr;
ppl_Linear_Expression_t le;
ppl_dimension_type i;
ppl_dimension_type dim;
ppl_Pointset_Powerset_C_Polyhedron_t temp;
/* Add the equality: t_{time_depth} = t'_{time_depth} + 1.
This is the core part of this alogrithm, since this
constraint asks for the memory access stride (difference)
between two consecutive points in time dimensions. */
ppl_Pointset_Powerset_C_Polyhedron_space_dimension (*p, &dim);
ppl_new_Linear_Expression_with_dimension (&le, dim);
ppl_set_coef (le, time_depth, 1);
ppl_set_coef (le, time_depth + offset, -1);
ppl_set_inhomogeneous (le, 1);
ppl_new_Constraint (&new_cstr, le, PPL_CONSTRAINT_TYPE_EQUAL);
ppl_Pointset_Powerset_C_Polyhedron_add_constraint (*p, new_cstr);
ppl_delete_Linear_Expression (le);
ppl_delete_Constraint (new_cstr);
/* Add equalities:
| t1 = t1'
| ...
| t_{time_depth-1} = t'_{time_depth-1}
| t_{time_depth+1} = t'_{time_depth+1}
| ...
| t_{dim_sctr} = t'_{dim_sctr}
This means that all the time dimensions are equal except for
time_depth, where the constraint is t_{depth} = t'_{depth} + 1
step. More to this: we should be carefull not to add equalities
to the 'coupled' dimensions, which happens when the one dimension
is stripmined dimension, and the other dimension corresponds
to the point loop inside stripmined dimension. */
ppl_new_Pointset_Powerset_C_Polyhedron_from_Pointset_Powerset_C_Polyhedron (&temp, *p);
for (i = 0; i < dim_sctr; i++)
if (i != time_depth)
{
ppl_new_Linear_Expression_with_dimension (&le, dim);
ppl_set_coef (le, i, 1);
ppl_set_coef (le, i + offset, -1);
ppl_new_Constraint (&new_cstr, le, PPL_CONSTRAINT_TYPE_EQUAL);
ppl_Pointset_Powerset_C_Polyhedron_add_constraint (temp, new_cstr);
if (ppl_Pointset_Powerset_C_Polyhedron_is_empty (temp))
{
ppl_delete_Pointset_Powerset_C_Polyhedron (temp);
ppl_new_Pointset_Powerset_C_Polyhedron_from_Pointset_Powerset_C_Polyhedron (&temp, *p);
}
else
ppl_Pointset_Powerset_C_Polyhedron_add_constraint (*p, new_cstr);
ppl_delete_Linear_Expression (le);
ppl_delete_Constraint (new_cstr);
}
ppl_delete_Pointset_Powerset_C_Polyhedron (temp);
}
/* Set STRIDE to the stride of PDR in memory by advancing by one in
time dimension DEPTH. */
@ -215,48 +303,11 @@ memory_stride_in_loop (Value stride, graphite_dim_t depth, poly_dr_p pdr)
free (map);
}
/* Add equalities:
| t1 = t1'
| ...
| t_{depth-1} = t'_{depth-1}
| t_{depth+1} = t'_{depth+1}
| ...
| t_{dim_sctr} = t'_{dim_sctr}
This means that all the time dimensions are equal except for
depth, where we will add t_{depth} = t'_{depth} + 1 in the next
step. */
time_depth = psct_dynamic_dim (pbb, depth);
for (i = 0; i < dim_sctr; i++)
if (i != time_depth)
{
ppl_new_Linear_Expression_with_dimension (&le, new_dim);
ppl_set_coef (le, i, 1);
ppl_set_coef (le, i + offset, -1);
ppl_new_Constraint (&new_cstr, le, PPL_CONSTRAINT_TYPE_EQUAL);
ppl_Pointset_Powerset_C_Polyhedron_add_constraint (p2, new_cstr);
ppl_delete_Linear_Expression (le);
ppl_delete_Constraint (new_cstr);
}
/* Add equality : t_{depth} = t'_{depth} + 1.
This is the core part of this alogrithm, since this
constraint asks for the memory access stride (difference)
between two consecutive points in time dimensions. */
{
ppl_new_Linear_Expression_with_dimension (&le, new_dim);
ppl_set_coef (le, time_depth, 1);
ppl_set_coef (le, time_depth + offset, -1);
ppl_set_inhomogeneous (le, 1);
ppl_new_Constraint (&new_cstr, le, PPL_CONSTRAINT_TYPE_EQUAL);
ppl_Pointset_Powerset_C_Polyhedron_add_constraint (p2, new_cstr);
ppl_delete_Linear_Expression (le);
ppl_delete_Constraint (new_cstr);
}
/* P1 = P1 inter P2. */
ppl_Pointset_Powerset_C_Polyhedron_intersection_assign (p1, p2);
build_partial_difference (&p1, time_depth, offset, dim_sctr);
/* Maximise the expression L2 - L1. */
{
@ -266,6 +317,13 @@ memory_stride_in_loop (Value stride, graphite_dim_t depth, poly_dr_p pdr)
ppl_max_for_le_pointset (p1, le, stride);
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "\nStride in BB_%d, DR_%d, depth %d:",
pbb_index (pbb), PDR_ID (pdr), (int) depth);
value_print (dump_file, " %s ", stride);
}
ppl_delete_Pointset_Powerset_C_Polyhedron (p1);
ppl_delete_Pointset_Powerset_C_Polyhedron (p2);
ppl_delete_Linear_Expression (le);