/* Data dependence analysis for Graphite. Copyright (C) 2009-2014 Free Software Foundation, Inc. Contributed by Sebastian Pop and Konrad Trifunovic . This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see . */ #include "config.h" #ifdef HAVE_isl #include #include #include #include #include #ifdef HAVE_cloog #include #include #endif #endif #include "system.h" #include "coretypes.h" #include "tree.h" #include "predict.h" #include "vec.h" #include "hashtab.h" #include "hash-set.h" #include "machmode.h" #include "tm.h" #include "hard-reg-set.h" #include "input.h" #include "function.h" #include "dominance.h" #include "cfg.h" #include "basic-block.h" #include "tree-ssa-alias.h" #include "internal-fn.h" #include "gimple-expr.h" #include "is-a.h" #include "gimple.h" #include "gimple-iterator.h" #include "tree-ssa-loop.h" #include "tree-pass.h" #include "cfgloop.h" #include "tree-chrec.h" #include "tree-data-ref.h" #include "tree-scalar-evolution.h" #include "sese.h" #ifdef HAVE_isl #include "graphite-poly.h" #include "graphite-htab.h" isl_union_map * scop_get_dependences (scop_p scop) { isl_union_map *dependences; if (!scop->must_raw) compute_deps (scop, SCOP_BBS (scop), &scop->must_raw, &scop->may_raw, &scop->must_raw_no_source, &scop->may_raw_no_source, &scop->must_war, &scop->may_war, &scop->must_war_no_source, &scop->may_war_no_source, &scop->must_waw, &scop->may_waw, &scop->must_waw_no_source, &scop->may_waw_no_source); dependences = isl_union_map_copy (scop->must_raw); dependences = isl_union_map_union (dependences, isl_union_map_copy (scop->must_war)); dependences = isl_union_map_union (dependences, isl_union_map_copy (scop->must_waw)); dependences = isl_union_map_union (dependences, isl_union_map_copy (scop->may_raw)); dependences = isl_union_map_union (dependences, isl_union_map_copy (scop->may_war)); dependences = isl_union_map_union (dependences, isl_union_map_copy (scop->may_waw)); return dependences; } /* Add the constraints from the set S to the domain of MAP. */ static isl_map * constrain_domain (isl_map *map, isl_set *s) { isl_space *d = isl_map_get_space (map); isl_id *id = isl_space_get_tuple_id (d, isl_dim_in); s = isl_set_set_tuple_id (s, id); isl_space_free (d); return isl_map_intersect_domain (map, s); } /* Constrain pdr->accesses with pdr->extent and pbb->domain. */ static isl_map * add_pdr_constraints (poly_dr_p pdr, poly_bb_p pbb) { isl_map *x = isl_map_intersect_range (isl_map_copy (pdr->accesses), isl_set_copy (pdr->extent)); x = constrain_domain (x, isl_set_copy (pbb->domain)); return x; } /* Returns all the memory reads in SCOP. */ static isl_union_map * scop_get_reads (scop_p scop, vec pbbs) { int i, j; poly_bb_p pbb; poly_dr_p pdr; isl_space *space = isl_set_get_space (scop->context); isl_union_map *res = isl_union_map_empty (space); FOR_EACH_VEC_ELT (pbbs, i, pbb) { FOR_EACH_VEC_ELT (PBB_DRS (pbb), j, pdr) if (pdr_read_p (pdr)) res = isl_union_map_add_map (res, add_pdr_constraints (pdr, pbb)); } return res; } /* Returns all the memory must writes in SCOP. */ static isl_union_map * scop_get_must_writes (scop_p scop, vec pbbs) { int i, j; poly_bb_p pbb; poly_dr_p pdr; isl_space *space = isl_set_get_space (scop->context); isl_union_map *res = isl_union_map_empty (space); FOR_EACH_VEC_ELT (pbbs, i, pbb) { FOR_EACH_VEC_ELT (PBB_DRS (pbb), j, pdr) if (pdr_write_p (pdr)) res = isl_union_map_add_map (res, add_pdr_constraints (pdr, pbb)); } return res; } /* Returns all the memory may writes in SCOP. */ static isl_union_map * scop_get_may_writes (scop_p scop, vec pbbs) { int i, j; poly_bb_p pbb; poly_dr_p pdr; isl_space *space = isl_set_get_space (scop->context); isl_union_map *res = isl_union_map_empty (space); FOR_EACH_VEC_ELT (pbbs, i, pbb) { FOR_EACH_VEC_ELT (PBB_DRS (pbb), j, pdr) if (pdr_may_write_p (pdr)) res = isl_union_map_add_map (res, add_pdr_constraints (pdr, pbb)); } return res; } /* Returns all the original schedules in SCOP. */ static isl_union_map * scop_get_original_schedule (scop_p scop, vec pbbs) { int i; poly_bb_p pbb; isl_space *space = isl_set_get_space (scop->context); isl_union_map *res = isl_union_map_empty (space); FOR_EACH_VEC_ELT (pbbs, i, pbb) { res = isl_union_map_add_map (res, constrain_domain (isl_map_copy (pbb->schedule), isl_set_copy (pbb->domain))); } return res; } /* Returns all the transformed schedules in SCOP. */ static isl_union_map * scop_get_transformed_schedule (scop_p scop, vec pbbs) { int i; poly_bb_p pbb; isl_space *space = isl_set_get_space (scop->context); isl_union_map *res = isl_union_map_empty (space); FOR_EACH_VEC_ELT (pbbs, i, pbb) { res = isl_union_map_add_map (res, constrain_domain (isl_map_copy (pbb->transformed), isl_set_copy (pbb->domain))); } return res; } /* Helper function used on each MAP of a isl_union_map. Computes the maximal output dimension. */ static int max_number_of_out_dimensions (__isl_take isl_map *map, void *user) { int global_max = *((int *) user); isl_space *space = isl_map_get_space (map); int nb_out = isl_space_dim (space, isl_dim_out); if (global_max < nb_out) *((int *) user) = nb_out; isl_map_free (map); isl_space_free (space); return 0; } /* Extends the output dimension of MAP to MAX dimensions. */ static __isl_give isl_map * extend_map (__isl_take isl_map *map, int max) { isl_space *space = isl_map_get_space (map); int n = isl_space_dim (space, isl_dim_out); isl_space_free (space); return isl_map_add_dims (map, isl_dim_out, max - n); } /* Structure used to pass parameters to extend_schedule_1. */ struct extend_schedule_str { int max; isl_union_map *umap; }; /* Helper function for extend_schedule. */ static int extend_schedule_1 (__isl_take isl_map *map, void *user) { struct extend_schedule_str *str = (struct extend_schedule_str *) user; str->umap = isl_union_map_add_map (str->umap, extend_map (map, str->max)); return 0; } /* Return a relation that has uniform output dimensions. */ __isl_give isl_union_map * extend_schedule (__isl_take isl_union_map *x) { int max = 0; int res; struct extend_schedule_str str; res = isl_union_map_foreach_map (x, max_number_of_out_dimensions, (void *) &max); gcc_assert (res == 0); str.max = max; str.umap = isl_union_map_empty (isl_union_map_get_space (x)); res = isl_union_map_foreach_map (x, extend_schedule_1, (void *) &str); gcc_assert (res == 0); isl_union_map_free (x); return str.umap; } /* Applies SCHEDULE to the in and out dimensions of the dependences DEPS and return the resulting relation. */ static isl_map * apply_schedule_on_deps (__isl_keep isl_union_map *schedule, __isl_keep isl_union_map *deps) { isl_map *x; isl_union_map *ux, *trans; trans = isl_union_map_copy (schedule); trans = extend_schedule (trans); ux = isl_union_map_copy (deps); ux = isl_union_map_apply_domain (ux, isl_union_map_copy (trans)); ux = isl_union_map_apply_range (ux, trans); if (isl_union_map_is_empty (ux)) { isl_union_map_free (ux); return NULL; } x = isl_map_from_union_map (ux); return x; } /* Return true when SCHEDULE does not violate the data DEPS: that is when the intersection of LEX with the DEPS transformed by SCHEDULE is empty. LEX is the relation in which the outputs occur before the inputs. */ static bool no_violations (__isl_keep isl_union_map *schedule, __isl_keep isl_union_map *deps) { bool res; isl_space *space; isl_map *lex, *x; if (isl_union_map_is_empty (deps)) return true; x = apply_schedule_on_deps (schedule, deps); space = isl_map_get_space (x); space = isl_space_range (space); lex = isl_map_lex_ge (space); x = isl_map_intersect (x, lex); res = isl_map_is_empty (x); isl_map_free (x); return res; } /* Return true when DEPS is non empty and the intersection of LEX with the DEPS transformed by SCHEDULE is non empty. LEX is the relation in which all the inputs before DEPTH occur at the same time as the output, and the input at DEPTH occurs before output. */ bool carries_deps (__isl_keep isl_union_map *schedule, __isl_keep isl_union_map *deps, int depth) { bool res; int i; isl_space *space; isl_map *lex, *x; isl_constraint *ineq; if (isl_union_map_is_empty (deps)) return false; x = apply_schedule_on_deps (schedule, deps); if (x == NULL) return false; space = isl_map_get_space (x); space = isl_space_range (space); lex = isl_map_lex_le (space); space = isl_map_get_space (x); ineq = isl_inequality_alloc (isl_local_space_from_space (space)); for (i = 0; i < depth - 1; i++) lex = isl_map_equate (lex, isl_dim_in, i, isl_dim_out, i); /* in + 1 <= out */ ineq = isl_constraint_set_coefficient_si (ineq, isl_dim_out, depth - 1, 1); ineq = isl_constraint_set_coefficient_si (ineq, isl_dim_in, depth - 1, -1); ineq = isl_constraint_set_constant_si (ineq, -1); lex = isl_map_add_constraint (lex, ineq); x = isl_map_intersect (x, lex); res = !isl_map_is_empty (x); isl_map_free (x); return res; } /* Subtract from the RAW, WAR, and WAW dependences those relations that have been marked as belonging to an associative commutative reduction. */ static void subtract_commutative_associative_deps (scop_p scop, vec pbbs, isl_union_map *original, isl_union_map **must_raw, isl_union_map **may_raw, isl_union_map **must_raw_no_source, isl_union_map **may_raw_no_source, isl_union_map **must_war, isl_union_map **may_war, isl_union_map **must_war_no_source, isl_union_map **may_war_no_source, isl_union_map **must_waw, isl_union_map **may_waw, isl_union_map **must_waw_no_source, isl_union_map **may_waw_no_source) { int i, j; poly_bb_p pbb; poly_dr_p pdr; isl_space *space = isl_set_get_space (scop->context); FOR_EACH_VEC_ELT (pbbs, i, pbb) if (PBB_IS_REDUCTION (pbb)) { int res; isl_union_map *r = isl_union_map_empty (isl_space_copy (space)); isl_union_map *must_w = isl_union_map_empty (isl_space_copy (space)); isl_union_map *may_w = isl_union_map_empty (isl_space_copy (space)); isl_union_map *all_w; isl_union_map *empty; isl_union_map *x_must_raw; isl_union_map *x_may_raw; isl_union_map *x_must_raw_no_source; isl_union_map *x_may_raw_no_source; isl_union_map *x_must_war; isl_union_map *x_may_war; isl_union_map *x_must_war_no_source; isl_union_map *x_may_war_no_source; isl_union_map *x_must_waw; isl_union_map *x_may_waw; isl_union_map *x_must_waw_no_source; isl_union_map *x_may_waw_no_source; FOR_EACH_VEC_ELT (PBB_DRS (pbb), j, pdr) if (pdr_read_p (pdr)) r = isl_union_map_add_map (r, add_pdr_constraints (pdr, pbb)); FOR_EACH_VEC_ELT (PBB_DRS (pbb), j, pdr) if (pdr_write_p (pdr)) must_w = isl_union_map_add_map (must_w, add_pdr_constraints (pdr, pbb)); FOR_EACH_VEC_ELT (PBB_DRS (pbb), j, pdr) if (pdr_may_write_p (pdr)) may_w = isl_union_map_add_map (may_w, add_pdr_constraints (pdr, pbb)); all_w = isl_union_map_union (isl_union_map_copy (must_w), isl_union_map_copy (may_w)); empty = isl_union_map_empty (isl_union_map_get_space (all_w)); res = isl_union_map_compute_flow (isl_union_map_copy (r), isl_union_map_copy (must_w), isl_union_map_copy (may_w), isl_union_map_copy (original), &x_must_raw, &x_may_raw, &x_must_raw_no_source, &x_may_raw_no_source); gcc_assert (res == 0); res = isl_union_map_compute_flow (isl_union_map_copy (all_w), r, empty, isl_union_map_copy (original), &x_must_war, &x_may_war, &x_must_war_no_source, &x_may_war_no_source); gcc_assert (res == 0); res = isl_union_map_compute_flow (all_w, must_w, may_w, isl_union_map_copy (original), &x_must_waw, &x_may_waw, &x_must_waw_no_source, &x_may_waw_no_source); gcc_assert (res == 0); if (must_raw) *must_raw = isl_union_map_subtract (*must_raw, x_must_raw); else isl_union_map_free (x_must_raw); if (may_raw) *may_raw = isl_union_map_subtract (*may_raw, x_may_raw); else isl_union_map_free (x_may_raw); if (must_raw_no_source) *must_raw_no_source = isl_union_map_subtract (*must_raw_no_source, x_must_raw_no_source); else isl_union_map_free (x_must_raw_no_source); if (may_raw_no_source) *may_raw_no_source = isl_union_map_subtract (*may_raw_no_source, x_may_raw_no_source); else isl_union_map_free (x_may_raw_no_source); if (must_war) *must_war = isl_union_map_subtract (*must_war, x_must_war); else isl_union_map_free (x_must_war); if (may_war) *may_war = isl_union_map_subtract (*may_war, x_may_war); else isl_union_map_free (x_may_war); if (must_war_no_source) *must_war_no_source = isl_union_map_subtract (*must_war_no_source, x_must_war_no_source); else isl_union_map_free (x_must_war_no_source); if (may_war_no_source) *may_war_no_source = isl_union_map_subtract (*may_war_no_source, x_may_war_no_source); else isl_union_map_free (x_may_war_no_source); if (must_waw) *must_waw = isl_union_map_subtract (*must_waw, x_must_waw); else isl_union_map_free (x_must_waw); if (may_waw) *may_waw = isl_union_map_subtract (*may_waw, x_may_waw); else isl_union_map_free (x_may_waw); if (must_waw_no_source) *must_waw_no_source = isl_union_map_subtract (*must_waw_no_source, x_must_waw_no_source); else isl_union_map_free (x_must_waw_no_source); if (may_waw_no_source) *may_waw_no_source = isl_union_map_subtract (*may_waw_no_source, x_may_waw_no_source); else isl_union_map_free (x_may_waw_no_source); } isl_union_map_free (original); isl_space_free (space); } /* Compute the original data dependences in SCOP for all the reads and writes in PBBS. */ void compute_deps (scop_p scop, vec pbbs, isl_union_map **must_raw, isl_union_map **may_raw, isl_union_map **must_raw_no_source, isl_union_map **may_raw_no_source, isl_union_map **must_war, isl_union_map **may_war, isl_union_map **must_war_no_source, isl_union_map **may_war_no_source, isl_union_map **must_waw, isl_union_map **may_waw, isl_union_map **must_waw_no_source, isl_union_map **may_waw_no_source) { isl_union_map *reads = scop_get_reads (scop, pbbs); isl_union_map *must_writes = scop_get_must_writes (scop, pbbs); isl_union_map *may_writes = scop_get_may_writes (scop, pbbs); isl_union_map *all_writes = isl_union_map_union (isl_union_map_copy (must_writes), isl_union_map_copy (may_writes)); isl_space *space = isl_union_map_get_space (all_writes); isl_union_map *empty = isl_union_map_empty (space); isl_union_map *original = scop_get_original_schedule (scop, pbbs); int res; res = isl_union_map_compute_flow (isl_union_map_copy (reads), isl_union_map_copy (must_writes), isl_union_map_copy (may_writes), isl_union_map_copy (original), must_raw, may_raw, must_raw_no_source, may_raw_no_source); gcc_assert (res == 0); res = isl_union_map_compute_flow (isl_union_map_copy (all_writes), reads, empty, isl_union_map_copy (original), must_war, may_war, must_war_no_source, may_war_no_source); gcc_assert (res == 0); res = isl_union_map_compute_flow (all_writes, must_writes, may_writes, isl_union_map_copy (original), must_waw, may_waw, must_waw_no_source, may_waw_no_source); gcc_assert (res == 0); subtract_commutative_associative_deps (scop, pbbs, original, must_raw, may_raw, must_raw_no_source, may_raw_no_source, must_war, may_war, must_war_no_source, may_war_no_source, must_waw, may_waw, must_waw_no_source, may_waw_no_source); } /* Given a TRANSFORM, check whether it respects the original dependences in SCOP. Returns true when TRANSFORM is a safe transformation. */ static bool transform_is_safe (scop_p scop, isl_union_map *transform) { bool res; if (!scop->must_raw) compute_deps (scop, SCOP_BBS (scop), &scop->must_raw, &scop->may_raw, &scop->must_raw_no_source, &scop->may_raw_no_source, &scop->must_war, &scop->may_war, &scop->must_war_no_source, &scop->may_war_no_source, &scop->must_waw, &scop->may_waw, &scop->must_waw_no_source, &scop->may_waw_no_source); res = (no_violations (transform, scop->must_raw) && no_violations (transform, scop->may_raw) && no_violations (transform, scop->must_war) && no_violations (transform, scop->may_war) && no_violations (transform, scop->must_waw) && no_violations (transform, scop->may_waw)); isl_union_map_free (transform); return res; } /* Return true when the SCOP transformed schedule is correct. */ bool graphite_legal_transform (scop_p scop) { int res; isl_union_map *transform; timevar_push (TV_GRAPHITE_DATA_DEPS); transform = scop_get_transformed_schedule (scop, SCOP_BBS (scop)); res = transform_is_safe (scop, transform); timevar_pop (TV_GRAPHITE_DATA_DEPS); return res; } #ifdef HAVE_cloog /* Return true when the loop at DEPTH carries dependences. BODY is the body of the loop. */ static bool loop_level_carries_dependences (scop_p scop, vec body, int depth) { isl_union_map *transform = scop_get_transformed_schedule (scop, body); isl_union_map *must_raw, *may_raw; isl_union_map *must_war, *may_war; isl_union_map *must_waw, *may_waw; int res; compute_deps (scop, body, &must_raw, &may_raw, NULL, NULL, &must_war, &may_war, NULL, NULL, &must_waw, &may_waw, NULL, NULL); res = (carries_deps (transform, must_raw, depth) || carries_deps (transform, may_raw, depth) || carries_deps (transform, must_war, depth) || carries_deps (transform, may_war, depth) || carries_deps (transform, must_waw, depth) || carries_deps (transform, may_waw, depth)); isl_union_map_free (transform); isl_union_map_free (must_raw); isl_union_map_free (may_raw); isl_union_map_free (must_war); isl_union_map_free (may_war); isl_union_map_free (must_waw); isl_union_map_free (may_waw); return res; } /* Returns true when the loop L at level DEPTH is parallel. BB_PBB_MAPPING is a map between a basic_block and its related poly_bb_p. */ bool loop_is_parallel_p (loop_p loop, bb_pbb_htab_type *bb_pbb_mapping, int depth) { bool dependences; scop_p scop; timevar_push (TV_GRAPHITE_DATA_DEPS); auto_vec body; scop = get_loop_body_pbbs (loop, bb_pbb_mapping, &body); dependences = loop_level_carries_dependences (scop, body, depth); timevar_pop (TV_GRAPHITE_DATA_DEPS); return !dependences; } #endif #endif