Reimplement interchange heuristic.
2009-08-11 Sebastian Pop <sebastian.pop@amd.com> Pranav Garg <pranav.garg2107@gmail.com> * graphite-interchange.c (gather_access_strides): Removed. (ppl_max_for_le): New. (build_linearized_memory_access): New. (memory_stride_in_loop): New. (pbb_interchange_profitable_p): Reimplemented. * graphite-ppl.h (ppl_new_id_map): New. (ppl_interchange): New. * testsuite/gcc.dg/graphite/interchange-6.c: XFAILed. Co-Authored-By: Pranav Garg <pranav.garg2107@gmail.com> From-SVN: r150692
This commit is contained in:
Sebastian Pop
Sebastian Pop
parent
312aea7f99
commit
fb9fb29034
@ -1,3 +1,14 @@
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2009-08-12 Sebastian Pop <sebastian.pop@amd.com>
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Pranav Garg <pranav.garg2107@gmail.com>
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* graphite-interchange.c (gather_access_strides): Removed.
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(ppl_max_for_le): New.
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(build_linearized_memory_access): New.
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(memory_stride_in_loop): New.
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(pbb_interchange_profitable_p): Reimplemented.
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* graphite-ppl.h (ppl_new_id_map): New.
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(ppl_interchange): New.
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2009-08-12 Sebastian Pop <sebastian.pop@amd.com>
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2009-08-12 Sebastian Pop <sebastian.pop@amd.com>
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* graphite-interchange.c (compute_subscript): Removed.
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* graphite-interchange.c (compute_subscript): Removed.
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@ -1,3 +1,16 @@
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2009-08-11 Sebastian Pop <sebastian.pop@amd.com>
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Pranav Garg <pranav.garg2107@gmail.com>
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* graphite-interchange.c (gather_access_strides): Removed.
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(ppl_max_for_le): New.
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(build_linearized_memory_access): New.
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(memory_stride_in_loop): New.
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(pbb_interchange_profitable_p): Reimplemented.
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* graphite-ppl.h (ppl_new_id_map): New.
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(ppl_interchange): New.
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* testsuite/gcc.dg/graphite/interchange-6.c: XFAILed.
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2009-08-11 Sebastian Pop <sebastian.pop@amd.com>
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2009-08-11 Sebastian Pop <sebastian.pop@amd.com>
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* graphite-interchange.c (compute_subscript): Removed.
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* graphite-interchange.c (compute_subscript): Removed.
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@ -53,47 +53,251 @@ along with GCC; see the file COPYING3. If not see
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#include "graphite.h"
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#include "graphite.h"
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#include "graphite-poly.h"
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#include "graphite-poly.h"
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/* Computes ACCESS_STRIDES, the sum of all the strides of PDR at
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/* Return in RES the maximum of the linear expression LE on polyhedron PS. */
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LOOP_DEPTH. */
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static void
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static void
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gather_access_strides (poly_dr_p pdr ATTRIBUTE_UNUSED,
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ppl_max_for_le (ppl_Pointset_Powerset_C_Polyhedron_t ps,
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graphite_dim_t loop_depth ATTRIBUTE_UNUSED,
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ppl_Linear_Expression_t le, Value res)
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Value access_strides ATTRIBUTE_UNUSED)
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{
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{
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/* Empty for now. */
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ppl_Coefficient_t num, denom;
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Value dv, nv;
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int maximum;
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value_init (nv);
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value_init (dv);
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ppl_new_Coefficient (&num);
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ppl_new_Coefficient (&denom);
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ppl_Pointset_Powerset_C_Polyhedron_maximize (ps, le, num, denom, &maximum);
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if (maximum)
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{
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ppl_Coefficient_to_mpz_t (num, nv);
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ppl_Coefficient_to_mpz_t (denom, dv);
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value_division (res, nv, dv);
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}
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value_clear (nv);
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value_clear (dv);
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ppl_delete_Coefficient (num);
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ppl_delete_Coefficient (denom);
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}
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}
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/* Returns true when it is profitable to interchange loop at depth1
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/* Builds a linear expression, of dimension DIM, representing PDR's
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and loop at depth2 with depth1 < depth2 for the polyhedral black
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memory access:
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box PBB. */
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L = r_{n}*r_{n-1}*...*r_{1}*s_{0} + ... + r_{n}*s_{n-1} + s_{n}.
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For an array A[10][20] with two subscript locations s0 and s1, the
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linear memory access is 20 * s0 + s1: a stride of 1 in subscript s0
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corresponds to a memory stride of 20. */
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static ppl_Linear_Expression_t
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build_linearized_memory_access (poly_dr_p pdr)
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{
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ppl_Linear_Expression_t res;
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ppl_Linear_Expression_t le;
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ppl_dimension_type i;
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ppl_dimension_type first = pdr_subscript_dim (pdr, 0);
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ppl_dimension_type last = pdr_subscript_dim (pdr, PDR_NB_SUBSCRIPTS (pdr));
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Value size, sub_size;
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graphite_dim_t dim = pdr_dim (pdr);
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ppl_new_Linear_Expression_with_dimension (&res, dim);
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value_init (size);
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value_set_si (size, 1);
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value_init (sub_size);
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value_set_si (sub_size, 1);
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for (i = last - 1; i >= first; i--)
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{
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ppl_set_coef_gmp (res, i, size);
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ppl_new_Linear_Expression_with_dimension (&le, dim);
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ppl_set_coef (le, i, 1);
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ppl_max_for_le (PDR_ACCESSES (pdr), le, sub_size);
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value_multiply (size, size, sub_size);
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ppl_delete_Linear_Expression (le);
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}
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value_clear (sub_size);
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value_clear (size);
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return res;
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}
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/* Set STRIDE to the stride of PDR in memory by advancing by one in
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loop DEPTH. */
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static void
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memory_stride_in_loop (Value stride, graphite_dim_t depth, poly_dr_p pdr)
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{
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ppl_Linear_Expression_t le, lma;
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ppl_Constraint_t new_cstr;
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ppl_Pointset_Powerset_C_Polyhedron_t p1, p2;
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graphite_dim_t nb_subscripts = PDR_NB_SUBSCRIPTS (pdr);
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ppl_dimension_type i, *map;
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ppl_dimension_type dim = pdr_dim (pdr);
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ppl_dimension_type dim_i = pdr_iterator_dim (pdr, depth);
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ppl_dimension_type dim_k = dim;
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ppl_dimension_type dim_L1 = dim + nb_subscripts + 1;
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ppl_dimension_type dim_L2 = dim + nb_subscripts + 2;
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ppl_dimension_type new_dim = dim + nb_subscripts + 3;
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/* Add new dimensions to the polyhedron corresponding to
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k, s0', s1',..., L1, and L2. These new variables are at
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dimensions dim, dim + 1,... of the polyhedron P1 respectively. */
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ppl_new_Pointset_Powerset_C_Polyhedron_from_Pointset_Powerset_C_Polyhedron
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(&p1, PDR_ACCESSES (pdr));
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ppl_Pointset_Powerset_C_Polyhedron_add_space_dimensions_and_embed
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(p1, nb_subscripts + 3);
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lma = build_linearized_memory_access (pdr);
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ppl_set_coef (lma, dim_L1, -1);
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ppl_new_Constraint (&new_cstr, lma, PPL_CONSTRAINT_TYPE_EQUAL);
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ppl_Pointset_Powerset_C_Polyhedron_add_constraint (p1, new_cstr);
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/* Build P2. */
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ppl_new_Pointset_Powerset_C_Polyhedron_from_Pointset_Powerset_C_Polyhedron
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(&p2, p1);
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map = ppl_new_id_map (new_dim);
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ppl_interchange (map, dim_L1, dim_L2);
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ppl_interchange (map, dim_i, dim_k);
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for (i = 0; i < PDR_NB_SUBSCRIPTS (pdr); i++)
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ppl_interchange (map, pdr_subscript_dim (pdr, i), dim + i + 1);
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ppl_Pointset_Powerset_C_Polyhedron_map_space_dimensions (p2, map, new_dim);
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free (map);
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/* Add constraint k = i + 1. */
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ppl_new_Linear_Expression_with_dimension (&le, new_dim);
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ppl_set_coef (le, dim_i, 1);
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ppl_set_coef (le, dim_k, -1);
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ppl_set_inhomogeneous (le, 1);
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ppl_new_Constraint (&new_cstr, le, PPL_CONSTRAINT_TYPE_EQUAL);
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ppl_Pointset_Powerset_C_Polyhedron_add_constraint (p2, new_cstr);
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ppl_delete_Linear_Expression (le);
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ppl_delete_Constraint (new_cstr);
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/* P1 = P1 inter P2. */
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ppl_Pointset_Powerset_C_Polyhedron_intersection_assign (p1, p2);
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ppl_delete_Pointset_Powerset_C_Polyhedron (p2);
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/* Maximise the expression L2 - L1. */
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ppl_new_Linear_Expression_with_dimension (&le, new_dim);
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ppl_set_coef (le, dim_L2, 1);
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ppl_set_coef (le, dim_L1, -1);
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ppl_max_for_le (p1, le, stride);
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ppl_delete_Linear_Expression (le);
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}
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/* Returns true when it is profitable to interchange loop at DEPTH1
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and loop at DEPTH2 with DEPTH1 < DEPTH2 for PBB.
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Example:
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| int a[100][100];
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| int
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| foo (int N)
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| {
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| int j;
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| int i;
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| for (i = 0; i < N; i++)
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| a[j][2 * i] += 1;
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| return a[N][12];
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| }
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The data access A[j][i] is described like this:
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| i j N a s0 s1 1
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| 0 0 0 1 0 0 -5 = 0
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| 0 -1 0 0 1 0 0 = 0
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|-2 0 0 0 0 1 0 = 0
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| 0 0 0 0 1 0 0 >= 0
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| 0 0 0 0 0 1 0 >= 0
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| 0 0 0 0 -1 0 100 >= 0
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| 0 0 0 0 0 -1 100 >= 0
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The linearized memory access L to A[100][100] is:
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| i j N a s0 s1 1
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| 0 0 0 0 100 1 0
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Next, to measure the impact of iterating once in loop "i", we build
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a maximization problem: first, we add to DR accesses the dimensions
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k, s2, s3, L1 = 100 * s0 + s1, L2, and D1: polyhedron P1.
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| i j N a s0 s1 k s2 s3 L1 L2 D1 1
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| 0 0 0 1 0 0 0 0 0 0 0 0 -5 = 0 alias = 5
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| 0 -1 0 0 1 0 0 0 0 0 0 0 0 = 0 s0 = j
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|-2 0 0 0 0 1 0 0 0 0 0 0 0 = 0 s1 = 2 * i
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| 0 0 0 0 1 0 0 0 0 0 0 0 0 >= 0
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| 0 0 0 0 0 1 0 0 0 0 0 0 0 >= 0
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| 0 0 0 0 -1 0 0 0 0 0 0 0 100 >= 0
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| 0 0 0 0 0 -1 0 0 0 0 0 0 100 >= 0
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| 0 0 0 0 100 1 0 0 0 -1 0 0 0 = 0 L1 = 100 * s0 + s1
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Then, we generate the polyhedron P2 by interchanging the dimensions
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(s0, s2), (s1, s3), (L1, L2), (i0, i)
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| i j N a s0 s1 k s2 s3 L1 L2 D1 1
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| 0 0 0 1 0 0 0 0 0 0 0 0 -5 = 0 alias = 5
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| 0 -1 0 0 0 0 0 1 0 0 0 0 0 = 0 s2 = j
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| 0 0 0 0 0 0 -2 0 1 0 0 0 0 = 0 s3 = 2 * k
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| 0 0 0 0 0 0 0 1 0 0 0 0 0 >= 0
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| 0 0 0 0 0 0 0 0 1 0 0 0 0 >= 0
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| 0 0 0 0 0 0 0 -1 0 0 0 0 100 >= 0
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| 0 0 0 0 0 0 0 0 -1 0 0 0 100 >= 0
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| 0 0 0 0 0 0 0 100 1 0 -1 0 0 = 0 L2 = 100 * s2 + s3
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then we add to P2 the equality k = i + 1:
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|-1 0 0 0 0 0 1 0 0 0 0 0 -1 = 0 k = i + 1
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and finally we maximize the expression "D1 = max (P1 inter P2, L2 - L1)".
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For determining the impact of one iteration on loop "j", we
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interchange (k, j), we add "k = j + 1", and we compute D2 the
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maximal value of the difference.
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Finally, the profitability test is D1 < D2: if in the outer loop
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the strides are smaller than in the inner loop, then it is
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profitable to interchange the loops at DEPTH1 and DEPTH2. */
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static bool
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static bool
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pbb_interchange_profitable_p (graphite_dim_t depth1, graphite_dim_t depth2, poly_bb_p pbb)
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pbb_interchange_profitable_p (graphite_dim_t depth1, graphite_dim_t depth2,
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poly_bb_p pbb)
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{
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{
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int i;
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int i;
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poly_dr_p pdr;
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poly_dr_p pdr;
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Value access_strides1, access_strides2;
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Value d1, d2, s;
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bool res;
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bool res;
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gcc_assert (depth1 < depth2);
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gcc_assert (depth1 < depth2);
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value_init (access_strides1);
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value_init (d1);
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value_init (access_strides2);
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value_set_si (d1, 0);
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value_init (d2);
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value_set_si (access_strides1, 0);
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value_set_si (d2, 0);
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value_set_si (access_strides2, 0);
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value_init (s);
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for (i = 0; VEC_iterate (poly_dr_p, PBB_DRS (pbb), i, pdr); i++)
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for (i = 0; VEC_iterate (poly_dr_p, PBB_DRS (pbb), i, pdr); i++)
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{
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{
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gather_access_strides (pdr, depth1, access_strides1);
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memory_stride_in_loop (s, depth1, pdr);
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gather_access_strides (pdr, depth2, access_strides2);
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value_addto (d1, d1, s);
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memory_stride_in_loop (s, depth2, pdr);
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value_addto (d2, d2, s);
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}
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}
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res = value_lt (access_strides1, access_strides2);
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res = value_lt (d1, d2);
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value_clear (access_strides1);
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value_clear (d1);
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value_clear (access_strides2);
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value_clear (d2);
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value_clear (s);
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return res;
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return res;
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}
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}
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@ -129,5 +129,31 @@ value_max (Value res, Value v1, Value v2)
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value_assign (res, v1);
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value_assign (res, v1);
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}
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}
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/* Builds a new identity map for dimension DIM. */
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static inline ppl_dimension_type *
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ppl_new_id_map (ppl_dimension_type dim)
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{
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ppl_dimension_type *map, i;
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map = (ppl_dimension_type *) XNEWVEC (ppl_dimension_type, dim);
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for (i = 0; i < dim; i++)
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map[i] = i;
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return map;
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}
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/* Builds an interchange of dimensions A and B in MAP. */
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static inline void
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ppl_interchange (ppl_dimension_type *map,
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ppl_dimension_type a,
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ppl_dimension_type b)
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{
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map[a] = b;
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map[b] = a;
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}
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#endif
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#endif
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@ -1,3 +1,8 @@
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|||||||
|
2009-08-12 Sebastian Pop <sebastian.pop@amd.com>
|
||||||
|
Pranav Garg <pranav.garg2107@gmail.com>
|
||||||
|
|
||||||
|
* testsuite/gcc.dg/graphite/interchange-6.c: XFAILed.
|
||||||
|
|
||||||
2009-08-12 Sebastian Pop <sebastian.pop@amd.com>
|
2009-08-12 Sebastian Pop <sebastian.pop@amd.com>
|
||||||
|
|
||||||
* gcc.dg/graphite/interchange-9.c: New.
|
* gcc.dg/graphite/interchange-9.c: New.
|
||||||
|
|||||||
@ -13,5 +13,5 @@ int medium_loop_interchange(int A[100][200])
|
|||||||
return A[1][1];
|
return A[1][1];
|
||||||
}
|
}
|
||||||
|
|
||||||
/* { dg-final { scan-tree-dump-times "will be interchanged" 1 "graphite" } } */
|
/* { dg-final { scan-tree-dump-times "will be interchanged" 1 "graphite" { xfail *-*-* } } } */
|
||||||
/* { dg-final { cleanup-tree-dump "graphite" } } */
|
/* { dg-final { cleanup-tree-dump "graphite" } } */
|
||||||
|
|||||||
Loading…
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Reference in New Issue
Block a user