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dea61d92 | 1 | /* Loop distribution. |
b03c3082 | 2 | Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 |
c75c517d | 3 | Free Software Foundation, Inc. |
dea61d92 SP |
4 | Contributed by Georges-Andre Silber <Georges-Andre.Silber@ensmp.fr> |
5 | and Sebastian Pop <sebastian.pop@amd.com>. | |
6 | ||
7 | This file is part of GCC. | |
b8698a0f | 8 | |
dea61d92 SP |
9 | GCC is free software; you can redistribute it and/or modify it |
10 | under the terms of the GNU General Public License as published by the | |
11 | Free Software Foundation; either version 3, or (at your option) any | |
12 | later version. | |
b8698a0f | 13 | |
dea61d92 SP |
14 | GCC is distributed in the hope that it will be useful, but WITHOUT |
15 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
16 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
17 | for more details. | |
b8698a0f | 18 | |
dea61d92 SP |
19 | You should have received a copy of the GNU General Public License |
20 | along with GCC; see the file COPYING3. If not see | |
21 | <http://www.gnu.org/licenses/>. */ | |
22 | ||
23 | /* This pass performs loop distribution: for example, the loop | |
24 | ||
25 | |DO I = 2, N | |
26 | | A(I) = B(I) + C | |
27 | | D(I) = A(I-1)*E | |
28 | |ENDDO | |
29 | ||
b8698a0f | 30 | is transformed to |
dea61d92 SP |
31 | |
32 | |DOALL I = 2, N | |
33 | | A(I) = B(I) + C | |
34 | |ENDDO | |
35 | | | |
36 | |DOALL I = 2, N | |
37 | | D(I) = A(I-1)*E | |
38 | |ENDDO | |
39 | ||
40 | This pass uses an RDG, Reduced Dependence Graph built on top of the | |
41 | data dependence relations. The RDG is then topologically sorted to | |
42 | obtain a map of information producers/consumers based on which it | |
43 | generates the new loops. */ | |
44 | ||
45 | #include "config.h" | |
46 | #include "system.h" | |
47 | #include "coretypes.h" | |
dea61d92 | 48 | #include "tree-flow.h" |
dea61d92 | 49 | #include "cfgloop.h" |
dea61d92 SP |
50 | #include "tree-chrec.h" |
51 | #include "tree-data-ref.h" | |
52 | #include "tree-scalar-evolution.h" | |
53 | #include "tree-pass.h" | |
dea61d92 | 54 | |
30d55936 RG |
55 | enum partition_kind { PKIND_NORMAL, PKIND_MEMSET }; |
56 | ||
c61f8985 RG |
57 | typedef struct partition_s |
58 | { | |
59 | bitmap stmts; | |
30d55936 RG |
60 | enum partition_kind kind; |
61 | /* Main statement a kind != PKIND_NORMAL partition is about. */ | |
62 | gimple main_stmt; | |
c61f8985 RG |
63 | } *partition_t; |
64 | ||
65 | DEF_VEC_P (partition_t); | |
66 | DEF_VEC_ALLOC_P (partition_t, heap); | |
67 | ||
68 | /* Allocate and initialize a partition from BITMAP. */ | |
69 | ||
70 | static partition_t | |
71 | partition_alloc (bitmap stmts) | |
72 | { | |
73 | partition_t partition = XCNEW (struct partition_s); | |
74 | partition->stmts = stmts ? stmts : BITMAP_ALLOC (NULL); | |
30d55936 | 75 | partition->kind = PKIND_NORMAL; |
c61f8985 RG |
76 | return partition; |
77 | } | |
78 | ||
79 | /* Free PARTITION. */ | |
80 | ||
81 | static void | |
82 | partition_free (partition_t partition) | |
83 | { | |
84 | BITMAP_FREE (partition->stmts); | |
85 | free (partition); | |
86 | } | |
87 | ||
30d55936 RG |
88 | /* Returns true if the partition can be generated as a builtin. */ |
89 | ||
90 | static bool | |
91 | partition_builtin_p (partition_t partition) | |
92 | { | |
93 | return partition->kind != PKIND_NORMAL; | |
94 | } | |
c61f8985 | 95 | |
dea61d92 SP |
96 | /* If bit I is not set, it means that this node represents an |
97 | operation that has already been performed, and that should not be | |
98 | performed again. This is the subgraph of remaining important | |
99 | computations that is passed to the DFS algorithm for avoiding to | |
100 | include several times the same stores in different loops. */ | |
101 | static bitmap remaining_stmts; | |
102 | ||
103 | /* A node of the RDG is marked in this bitmap when it has as a | |
104 | predecessor a node that writes to memory. */ | |
105 | static bitmap upstream_mem_writes; | |
106 | ||
c07a8cb3 RG |
107 | /* Returns true when DEF is an SSA_NAME defined in LOOP and used after |
108 | the LOOP. */ | |
109 | ||
110 | static bool | |
111 | ssa_name_has_uses_outside_loop_p (tree def, loop_p loop) | |
112 | { | |
113 | imm_use_iterator imm_iter; | |
114 | use_operand_p use_p; | |
115 | ||
116 | FOR_EACH_IMM_USE_FAST (use_p, imm_iter, def) | |
117 | if (loop != loop_containing_stmt (USE_STMT (use_p))) | |
118 | return true; | |
119 | ||
120 | return false; | |
121 | } | |
122 | ||
123 | /* Returns true when STMT defines a scalar variable used after the | |
88af7c1a | 124 | loop LOOP. */ |
c07a8cb3 RG |
125 | |
126 | static bool | |
88af7c1a | 127 | stmt_has_scalar_dependences_outside_loop (loop_p loop, gimple stmt) |
c07a8cb3 | 128 | { |
88af7c1a RG |
129 | def_operand_p def_p; |
130 | ssa_op_iter op_iter; | |
c07a8cb3 | 131 | |
9ca86fc3 RG |
132 | if (gimple_code (stmt) == GIMPLE_PHI) |
133 | return ssa_name_has_uses_outside_loop_p (gimple_phi_result (stmt), loop); | |
134 | ||
88af7c1a RG |
135 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, op_iter, SSA_OP_DEF) |
136 | if (ssa_name_has_uses_outside_loop_p (DEF_FROM_PTR (def_p), loop)) | |
137 | return true; | |
c07a8cb3 | 138 | |
88af7c1a | 139 | return false; |
c07a8cb3 RG |
140 | } |
141 | ||
dea61d92 SP |
142 | /* Update the PHI nodes of NEW_LOOP. NEW_LOOP is a duplicate of |
143 | ORIG_LOOP. */ | |
144 | ||
145 | static void | |
146 | update_phis_for_loop_copy (struct loop *orig_loop, struct loop *new_loop) | |
147 | { | |
148 | tree new_ssa_name; | |
726a989a | 149 | gimple_stmt_iterator si_new, si_orig; |
dea61d92 SP |
150 | edge orig_loop_latch = loop_latch_edge (orig_loop); |
151 | edge orig_entry_e = loop_preheader_edge (orig_loop); | |
152 | edge new_loop_entry_e = loop_preheader_edge (new_loop); | |
153 | ||
154 | /* Scan the phis in the headers of the old and new loops | |
155 | (they are organized in exactly the same order). */ | |
726a989a RB |
156 | for (si_new = gsi_start_phis (new_loop->header), |
157 | si_orig = gsi_start_phis (orig_loop->header); | |
158 | !gsi_end_p (si_new) && !gsi_end_p (si_orig); | |
159 | gsi_next (&si_new), gsi_next (&si_orig)) | |
dea61d92 | 160 | { |
726a989a | 161 | tree def; |
f5045c96 | 162 | source_location locus; |
726a989a RB |
163 | gimple phi_new = gsi_stmt (si_new); |
164 | gimple phi_orig = gsi_stmt (si_orig); | |
165 | ||
dea61d92 SP |
166 | /* Add the first phi argument for the phi in NEW_LOOP (the one |
167 | associated with the entry of NEW_LOOP) */ | |
726a989a | 168 | def = PHI_ARG_DEF_FROM_EDGE (phi_orig, orig_entry_e); |
f5045c96 AM |
169 | locus = gimple_phi_arg_location_from_edge (phi_orig, orig_entry_e); |
170 | add_phi_arg (phi_new, def, new_loop_entry_e, locus); | |
dea61d92 SP |
171 | |
172 | /* Add the second phi argument for the phi in NEW_LOOP (the one | |
173 | associated with the latch of NEW_LOOP) */ | |
174 | def = PHI_ARG_DEF_FROM_EDGE (phi_orig, orig_loop_latch); | |
f5045c96 | 175 | locus = gimple_phi_arg_location_from_edge (phi_orig, orig_loop_latch); |
dea61d92 SP |
176 | |
177 | if (TREE_CODE (def) == SSA_NAME) | |
178 | { | |
179 | new_ssa_name = get_current_def (def); | |
180 | ||
181 | if (!new_ssa_name) | |
182 | /* This only happens if there are no definitions inside the | |
61226dc8 SP |
183 | loop. Use the the invariant in the new loop as is. */ |
184 | new_ssa_name = def; | |
dea61d92 SP |
185 | } |
186 | else | |
187 | /* Could be an integer. */ | |
188 | new_ssa_name = def; | |
189 | ||
f5045c96 | 190 | add_phi_arg (phi_new, new_ssa_name, loop_latch_edge (new_loop), locus); |
dea61d92 SP |
191 | } |
192 | } | |
193 | ||
194 | /* Return a copy of LOOP placed before LOOP. */ | |
195 | ||
196 | static struct loop * | |
197 | copy_loop_before (struct loop *loop) | |
198 | { | |
199 | struct loop *res; | |
200 | edge preheader = loop_preheader_edge (loop); | |
201 | ||
dea61d92 SP |
202 | initialize_original_copy_tables (); |
203 | res = slpeel_tree_duplicate_loop_to_edge_cfg (loop, preheader); | |
30d55936 | 204 | gcc_assert (res != NULL); |
dea61d92 SP |
205 | free_original_copy_tables (); |
206 | ||
dea61d92 SP |
207 | update_phis_for_loop_copy (loop, res); |
208 | rename_variables_in_loop (res); | |
209 | ||
210 | return res; | |
211 | } | |
212 | ||
213 | /* Creates an empty basic block after LOOP. */ | |
214 | ||
215 | static void | |
216 | create_bb_after_loop (struct loop *loop) | |
217 | { | |
218 | edge exit = single_exit (loop); | |
219 | ||
220 | if (!exit) | |
221 | return; | |
222 | ||
223 | split_edge (exit); | |
224 | } | |
225 | ||
226 | /* Generate code for PARTITION from the code in LOOP. The loop is | |
227 | copied when COPY_P is true. All the statements not flagged in the | |
228 | PARTITION bitmap are removed from the loop or from its copy. The | |
229 | statements are indexed in sequence inside a basic block, and the | |
30d55936 | 230 | basic blocks of a loop are taken in dom order. */ |
dea61d92 | 231 | |
30d55936 | 232 | static void |
c61f8985 RG |
233 | generate_loops_for_partition (struct loop *loop, partition_t partition, |
234 | bool copy_p) | |
dea61d92 SP |
235 | { |
236 | unsigned i, x; | |
726a989a | 237 | gimple_stmt_iterator bsi; |
dea61d92 SP |
238 | basic_block *bbs; |
239 | ||
240 | if (copy_p) | |
241 | { | |
242 | loop = copy_loop_before (loop); | |
30d55936 | 243 | gcc_assert (loop != NULL); |
dea61d92 SP |
244 | create_preheader (loop, CP_SIMPLE_PREHEADERS); |
245 | create_bb_after_loop (loop); | |
246 | } | |
247 | ||
dea61d92 SP |
248 | /* Remove stmts not in the PARTITION bitmap. The order in which we |
249 | visit the phi nodes and the statements is exactly as in | |
250 | stmts_from_loop. */ | |
251 | bbs = get_loop_body_in_dom_order (loop); | |
252 | ||
b03c3082 JJ |
253 | if (MAY_HAVE_DEBUG_STMTS) |
254 | for (x = 0, i = 0; i < loop->num_nodes; i++) | |
255 | { | |
256 | basic_block bb = bbs[i]; | |
257 | ||
258 | for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi)) | |
c61f8985 | 259 | if (!bitmap_bit_p (partition->stmts, x++)) |
b03c3082 JJ |
260 | reset_debug_uses (gsi_stmt (bsi)); |
261 | ||
262 | for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) | |
263 | { | |
264 | gimple stmt = gsi_stmt (bsi); | |
265 | if (gimple_code (stmt) != GIMPLE_LABEL | |
266 | && !is_gimple_debug (stmt) | |
c61f8985 | 267 | && !bitmap_bit_p (partition->stmts, x++)) |
b03c3082 JJ |
268 | reset_debug_uses (stmt); |
269 | } | |
270 | } | |
271 | ||
dea61d92 SP |
272 | for (x = 0, i = 0; i < loop->num_nodes; i++) |
273 | { | |
274 | basic_block bb = bbs[i]; | |
dea61d92 | 275 | |
726a989a | 276 | for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi);) |
c61f8985 | 277 | if (!bitmap_bit_p (partition->stmts, x++)) |
2706a615 RG |
278 | { |
279 | gimple phi = gsi_stmt (bsi); | |
280 | if (!is_gimple_reg (gimple_phi_result (phi))) | |
281 | mark_virtual_phi_result_for_renaming (phi); | |
282 | remove_phi_node (&bsi, true); | |
283 | } | |
dea61d92 | 284 | else |
726a989a | 285 | gsi_next (&bsi); |
dea61d92 | 286 | |
726a989a | 287 | for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi);) |
2706a615 RG |
288 | { |
289 | gimple stmt = gsi_stmt (bsi); | |
b03c3082 JJ |
290 | if (gimple_code (stmt) != GIMPLE_LABEL |
291 | && !is_gimple_debug (stmt) | |
c61f8985 | 292 | && !bitmap_bit_p (partition->stmts, x++)) |
2706a615 RG |
293 | { |
294 | unlink_stmt_vdef (stmt); | |
295 | gsi_remove (&bsi, true); | |
296 | release_defs (stmt); | |
297 | } | |
298 | else | |
299 | gsi_next (&bsi); | |
300 | } | |
dea61d92 SP |
301 | } |
302 | ||
303 | free (bbs); | |
dea61d92 SP |
304 | } |
305 | ||
ada39f0b | 306 | /* Build the size argument for a memset call. */ |
3661e899 TB |
307 | |
308 | static inline tree | |
fc81a369 RH |
309 | build_size_arg_loc (location_t loc, tree nb_iter, tree op, |
310 | gimple_seq *stmt_list) | |
3661e899 | 311 | { |
fc81a369 | 312 | gimple_seq stmts; |
0d82a1c8 RG |
313 | tree x = fold_build2_loc (loc, MULT_EXPR, size_type_node, |
314 | fold_convert_loc (loc, size_type_node, nb_iter), | |
315 | fold_convert_loc (loc, size_type_node, | |
316 | TYPE_SIZE_UNIT (TREE_TYPE (op)))); | |
fc81a369 RH |
317 | x = force_gimple_operand (x, &stmts, true, NULL); |
318 | gimple_seq_add_seq (stmt_list, stmts); | |
3661e899 | 319 | |
fc81a369 | 320 | return x; |
3661e899 TB |
321 | } |
322 | ||
30d55936 | 323 | /* Generate a call to memset for PARTITION in LOOP. */ |
dea61d92 | 324 | |
cfee318d | 325 | static void |
30d55936 | 326 | generate_memset_builtin (struct loop *loop, partition_t partition) |
dea61d92 | 327 | { |
30d55936 RG |
328 | gimple_stmt_iterator gsi; |
329 | gimple stmt, fn_call; | |
330 | tree op0, nb_iter, mem, fn, addr_base, nb_bytes; | |
fc81a369 | 331 | gimple_seq stmt_list = NULL, stmts; |
dea61d92 | 332 | struct data_reference *dr = XCNEW (struct data_reference); |
30d55936 RG |
333 | location_t loc; |
334 | bool res; | |
335 | ||
336 | stmt = partition->main_stmt; | |
337 | loc = gimple_location (stmt); | |
338 | op0 = gimple_assign_lhs (stmt); | |
339 | if (gimple_bb (stmt) == loop->latch) | |
340 | nb_iter = number_of_latch_executions (loop); | |
341 | else | |
342 | nb_iter = number_of_exit_cond_executions (loop); | |
343 | ||
344 | /* The new statements will be placed before LOOP. */ | |
345 | gsi = gsi_last_bb (loop_preheader_edge (loop)->src); | |
dea61d92 | 346 | |
dea61d92 SP |
347 | DR_STMT (dr) = stmt; |
348 | DR_REF (dr) = op0; | |
4e4452b6 | 349 | res = dr_analyze_innermost (dr, loop_containing_stmt (stmt)); |
cfee318d | 350 | gcc_assert (res && stride_of_unit_type_p (DR_STEP (dr), TREE_TYPE (op0))); |
5e37ea0e SP |
351 | |
352 | nb_bytes = build_size_arg_loc (loc, nb_iter, op0, &stmt_list); | |
353 | addr_base = size_binop_loc (loc, PLUS_EXPR, DR_OFFSET (dr), DR_INIT (dr)); | |
354 | addr_base = fold_convert_loc (loc, sizetype, addr_base); | |
dea61d92 SP |
355 | |
356 | /* Test for a negative stride, iterating over every element. */ | |
0d82a1c8 | 357 | if (tree_int_cst_sgn (DR_STEP (dr)) == -1) |
dea61d92 | 358 | { |
fc81a369 RH |
359 | addr_base = size_binop_loc (loc, MINUS_EXPR, addr_base, |
360 | fold_convert_loc (loc, sizetype, nb_bytes)); | |
6edd8198 AM |
361 | addr_base = size_binop_loc (loc, PLUS_EXPR, addr_base, |
362 | TYPE_SIZE_UNIT (TREE_TYPE (op0))); | |
dea61d92 | 363 | } |
dea61d92 | 364 | |
5d49b6a7 RG |
365 | addr_base = fold_build_pointer_plus_loc (loc, |
366 | DR_BASE_ADDRESS (dr), addr_base); | |
dea61d92 | 367 | mem = force_gimple_operand (addr_base, &stmts, true, NULL); |
726a989a | 368 | gimple_seq_add_seq (&stmt_list, stmts); |
dea61d92 | 369 | |
e79983f4 | 370 | fn = build_fold_addr_expr (builtin_decl_implicit (BUILT_IN_MEMSET)); |
726a989a RB |
371 | fn_call = gimple_build_call (fn, 3, mem, integer_zero_node, nb_bytes); |
372 | gimple_seq_add_stmt (&stmt_list, fn_call); | |
30d55936 | 373 | gsi_insert_seq_after (&gsi, stmt_list, GSI_CONTINUE_LINKING); |
dea61d92 SP |
374 | |
375 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
376 | fprintf (dump_file, "generated memset zero\n"); | |
377 | ||
dea61d92 | 378 | free_data_ref (dr); |
dea61d92 SP |
379 | } |
380 | ||
30d55936 | 381 | /* Remove and destroy the loop LOOP. */ |
dea61d92 | 382 | |
30d55936 RG |
383 | static void |
384 | destroy_loop (struct loop *loop) | |
dea61d92 | 385 | { |
30d55936 RG |
386 | unsigned nbbs = loop->num_nodes; |
387 | edge exit = single_exit (loop); | |
388 | basic_block src = loop_preheader_edge (loop)->src, dest = exit->dest; | |
dea61d92 | 389 | basic_block *bbs; |
30d55936 | 390 | unsigned i; |
dea61d92 SP |
391 | |
392 | bbs = get_loop_body_in_dom_order (loop); | |
393 | ||
30d55936 RG |
394 | redirect_edge_pred (exit, src); |
395 | exit->flags &= ~(EDGE_TRUE_VALUE|EDGE_FALSE_VALUE); | |
396 | exit->flags |= EDGE_FALLTHRU; | |
397 | cancel_loop_tree (loop); | |
398 | rescan_loop_exit (exit, false, true); | |
dea61d92 | 399 | |
30d55936 | 400 | for (i = 0; i < nbbs; i++) |
c014f6f5 RG |
401 | { |
402 | /* We have made sure to not leave any dangling uses of SSA | |
403 | names defined in the loop. With the exception of virtuals. | |
404 | Make sure we replace all uses of virtual defs that will remain | |
405 | outside of the loop with the bare symbol as delete_basic_block | |
406 | will release them. */ | |
407 | gimple_stmt_iterator gsi; | |
408 | for (gsi = gsi_start_phis (bbs[i]); !gsi_end_p (gsi); gsi_next (&gsi)) | |
409 | { | |
410 | gimple phi = gsi_stmt (gsi); | |
411 | if (!is_gimple_reg (gimple_phi_result (phi))) | |
412 | mark_virtual_phi_result_for_renaming (phi); | |
413 | } | |
414 | for (gsi = gsi_start_bb (bbs[i]); !gsi_end_p (gsi); gsi_next (&gsi)) | |
415 | { | |
416 | gimple stmt = gsi_stmt (gsi); | |
417 | tree vdef = gimple_vdef (stmt); | |
418 | if (vdef && TREE_CODE (vdef) == SSA_NAME) | |
419 | mark_virtual_operand_for_renaming (vdef); | |
420 | } | |
421 | delete_basic_block (bbs[i]); | |
422 | } | |
dea61d92 | 423 | free (bbs); |
30d55936 RG |
424 | |
425 | set_immediate_dominator (CDI_DOMINATORS, dest, | |
426 | recompute_dominator (CDI_DOMINATORS, dest)); | |
dea61d92 SP |
427 | } |
428 | ||
30d55936 | 429 | /* Generates code for PARTITION. */ |
dea61d92 | 430 | |
30d55936 | 431 | static void |
c61f8985 RG |
432 | generate_code_for_partition (struct loop *loop, partition_t partition, |
433 | bool copy_p) | |
dea61d92 | 434 | { |
30d55936 RG |
435 | switch (partition->kind) |
436 | { | |
437 | case PKIND_MEMSET: | |
438 | generate_memset_builtin (loop, partition); | |
439 | /* If this is the last partition for which we generate code, we have | |
440 | to destroy the loop. */ | |
441 | if (!copy_p) | |
442 | destroy_loop (loop); | |
443 | break; | |
444 | ||
445 | case PKIND_NORMAL: | |
446 | generate_loops_for_partition (loop, partition, copy_p); | |
447 | break; | |
448 | ||
449 | default: | |
450 | gcc_unreachable (); | |
451 | } | |
dea61d92 SP |
452 | } |
453 | ||
454 | ||
455 | /* Returns true if the node V of RDG cannot be recomputed. */ | |
456 | ||
457 | static bool | |
458 | rdg_cannot_recompute_vertex_p (struct graph *rdg, int v) | |
459 | { | |
460 | if (RDG_MEM_WRITE_STMT (rdg, v)) | |
461 | return true; | |
462 | ||
463 | return false; | |
464 | } | |
465 | ||
466 | /* Returns true when the vertex V has already been generated in the | |
467 | current partition (V is in PROCESSED), or when V belongs to another | |
468 | partition and cannot be recomputed (V is not in REMAINING_STMTS). */ | |
469 | ||
470 | static inline bool | |
471 | already_processed_vertex_p (bitmap processed, int v) | |
472 | { | |
473 | return (bitmap_bit_p (processed, v) | |
474 | || !bitmap_bit_p (remaining_stmts, v)); | |
475 | } | |
476 | ||
477 | /* Returns NULL when there is no anti-dependence among the successors | |
478 | of vertex V, otherwise returns the edge with the anti-dep. */ | |
479 | ||
480 | static struct graph_edge * | |
481 | has_anti_dependence (struct vertex *v) | |
482 | { | |
483 | struct graph_edge *e; | |
484 | ||
485 | if (v->succ) | |
486 | for (e = v->succ; e; e = e->succ_next) | |
487 | if (RDGE_TYPE (e) == anti_dd) | |
488 | return e; | |
489 | ||
490 | return NULL; | |
491 | } | |
492 | ||
493 | /* Returns true when V has an anti-dependence edge among its successors. */ | |
494 | ||
495 | static bool | |
496 | predecessor_has_mem_write (struct graph *rdg, struct vertex *v) | |
497 | { | |
498 | struct graph_edge *e; | |
499 | ||
500 | if (v->pred) | |
501 | for (e = v->pred; e; e = e->pred_next) | |
502 | if (bitmap_bit_p (upstream_mem_writes, e->src) | |
503 | /* Don't consider flow channels: a write to memory followed | |
504 | by a read from memory. These channels allow the split of | |
505 | the RDG in different partitions. */ | |
506 | && !RDG_MEM_WRITE_STMT (rdg, e->src)) | |
507 | return true; | |
508 | ||
509 | return false; | |
510 | } | |
511 | ||
512 | /* Initializes the upstream_mem_writes bitmap following the | |
513 | information from RDG. */ | |
514 | ||
515 | static void | |
516 | mark_nodes_having_upstream_mem_writes (struct graph *rdg) | |
517 | { | |
518 | int v, x; | |
519 | bitmap seen = BITMAP_ALLOC (NULL); | |
520 | ||
521 | for (v = rdg->n_vertices - 1; v >= 0; v--) | |
522 | if (!bitmap_bit_p (seen, v)) | |
523 | { | |
524 | unsigned i; | |
525 | VEC (int, heap) *nodes = VEC_alloc (int, heap, 3); | |
dea61d92 SP |
526 | |
527 | graphds_dfs (rdg, &v, 1, &nodes, false, NULL); | |
528 | ||
ac47786e | 529 | FOR_EACH_VEC_ELT (int, nodes, i, x) |
dea61d92 | 530 | { |
fcaa4ca4 | 531 | if (!bitmap_set_bit (seen, x)) |
dea61d92 SP |
532 | continue; |
533 | ||
dea61d92 SP |
534 | if (RDG_MEM_WRITE_STMT (rdg, x) |
535 | || predecessor_has_mem_write (rdg, &(rdg->vertices[x])) | |
536 | /* In anti dependences the read should occur before | |
537 | the write, this is why both the read and the write | |
538 | should be placed in the same partition. */ | |
539 | || has_anti_dependence (&(rdg->vertices[x]))) | |
540 | { | |
dea61d92 SP |
541 | bitmap_set_bit (upstream_mem_writes, x); |
542 | } | |
543 | } | |
544 | ||
545 | VEC_free (int, heap, nodes); | |
546 | } | |
547 | } | |
548 | ||
549 | /* Returns true when vertex u has a memory write node as a predecessor | |
550 | in RDG. */ | |
551 | ||
552 | static bool | |
553 | has_upstream_mem_writes (int u) | |
554 | { | |
555 | return bitmap_bit_p (upstream_mem_writes, u); | |
556 | } | |
557 | ||
c61f8985 RG |
558 | static void rdg_flag_vertex_and_dependent (struct graph *, int, partition_t, |
559 | bitmap, bitmap, bool *); | |
dea61d92 | 560 | |
dea61d92 SP |
561 | /* Flag the uses of U stopping following the information from |
562 | upstream_mem_writes. */ | |
563 | ||
564 | static void | |
c61f8985 | 565 | rdg_flag_uses (struct graph *rdg, int u, partition_t partition, bitmap loops, |
dea61d92 SP |
566 | bitmap processed, bool *part_has_writes) |
567 | { | |
dea61d92 SP |
568 | use_operand_p use_p; |
569 | struct vertex *x = &(rdg->vertices[u]); | |
726a989a | 570 | gimple stmt = RDGV_STMT (x); |
dea61d92 SP |
571 | struct graph_edge *anti_dep = has_anti_dependence (x); |
572 | ||
573 | /* Keep in the same partition the destination of an antidependence, | |
574 | because this is a store to the exact same location. Putting this | |
575 | in another partition is bad for cache locality. */ | |
576 | if (anti_dep) | |
577 | { | |
578 | int v = anti_dep->dest; | |
579 | ||
580 | if (!already_processed_vertex_p (processed, v)) | |
581 | rdg_flag_vertex_and_dependent (rdg, v, partition, loops, | |
582 | processed, part_has_writes); | |
583 | } | |
584 | ||
726a989a | 585 | if (gimple_code (stmt) != GIMPLE_PHI) |
dea61d92 | 586 | { |
5006671f | 587 | if ((use_p = gimple_vuse_op (stmt)) != NULL_USE_OPERAND_P) |
dea61d92 SP |
588 | { |
589 | tree use = USE_FROM_PTR (use_p); | |
590 | ||
591 | if (TREE_CODE (use) == SSA_NAME) | |
592 | { | |
726a989a | 593 | gimple def_stmt = SSA_NAME_DEF_STMT (use); |
dea61d92 SP |
594 | int v = rdg_vertex_for_stmt (rdg, def_stmt); |
595 | ||
596 | if (v >= 0 | |
597 | && !already_processed_vertex_p (processed, v)) | |
598 | rdg_flag_vertex_and_dependent (rdg, v, partition, loops, | |
599 | processed, part_has_writes); | |
600 | } | |
601 | } | |
602 | } | |
603 | ||
726a989a | 604 | if (is_gimple_assign (stmt) && has_upstream_mem_writes (u)) |
dea61d92 | 605 | { |
726a989a | 606 | tree op0 = gimple_assign_lhs (stmt); |
dea61d92 SP |
607 | |
608 | /* Scalar channels don't have enough space for transmitting data | |
609 | between tasks, unless we add more storage by privatizing. */ | |
610 | if (is_gimple_reg (op0)) | |
611 | { | |
612 | use_operand_p use_p; | |
613 | imm_use_iterator iter; | |
614 | ||
615 | FOR_EACH_IMM_USE_FAST (use_p, iter, op0) | |
616 | { | |
617 | int v = rdg_vertex_for_stmt (rdg, USE_STMT (use_p)); | |
618 | ||
619 | if (!already_processed_vertex_p (processed, v)) | |
620 | rdg_flag_vertex_and_dependent (rdg, v, partition, loops, | |
621 | processed, part_has_writes); | |
622 | } | |
623 | } | |
624 | } | |
625 | } | |
626 | ||
627 | /* Flag V from RDG as part of PARTITION, and also flag its loop number | |
628 | in LOOPS. */ | |
629 | ||
630 | static void | |
c61f8985 | 631 | rdg_flag_vertex (struct graph *rdg, int v, partition_t partition, bitmap loops, |
dea61d92 SP |
632 | bool *part_has_writes) |
633 | { | |
634 | struct loop *loop; | |
635 | ||
c61f8985 | 636 | if (!bitmap_set_bit (partition->stmts, v)) |
dea61d92 SP |
637 | return; |
638 | ||
639 | loop = loop_containing_stmt (RDG_STMT (rdg, v)); | |
640 | bitmap_set_bit (loops, loop->num); | |
dea61d92 SP |
641 | |
642 | if (rdg_cannot_recompute_vertex_p (rdg, v)) | |
643 | { | |
644 | *part_has_writes = true; | |
645 | bitmap_clear_bit (remaining_stmts, v); | |
646 | } | |
647 | } | |
648 | ||
649 | /* Flag in the bitmap PARTITION the vertex V and all its predecessors. | |
fa10beec | 650 | Also flag their loop number in LOOPS. */ |
dea61d92 SP |
651 | |
652 | static void | |
c61f8985 | 653 | rdg_flag_vertex_and_dependent (struct graph *rdg, int v, partition_t partition, |
dea61d92 SP |
654 | bitmap loops, bitmap processed, |
655 | bool *part_has_writes) | |
656 | { | |
657 | unsigned i; | |
658 | VEC (int, heap) *nodes = VEC_alloc (int, heap, 3); | |
659 | int x; | |
660 | ||
661 | bitmap_set_bit (processed, v); | |
662 | rdg_flag_uses (rdg, v, partition, loops, processed, part_has_writes); | |
663 | graphds_dfs (rdg, &v, 1, &nodes, false, remaining_stmts); | |
664 | rdg_flag_vertex (rdg, v, partition, loops, part_has_writes); | |
665 | ||
ac47786e | 666 | FOR_EACH_VEC_ELT (int, nodes, i, x) |
dea61d92 SP |
667 | if (!already_processed_vertex_p (processed, x)) |
668 | rdg_flag_vertex_and_dependent (rdg, x, partition, loops, processed, | |
669 | part_has_writes); | |
670 | ||
671 | VEC_free (int, heap, nodes); | |
672 | } | |
673 | ||
674 | /* Initialize CONDS with all the condition statements from the basic | |
675 | blocks of LOOP. */ | |
676 | ||
677 | static void | |
726a989a | 678 | collect_condition_stmts (struct loop *loop, VEC (gimple, heap) **conds) |
dea61d92 SP |
679 | { |
680 | unsigned i; | |
681 | edge e; | |
682 | VEC (edge, heap) *exits = get_loop_exit_edges (loop); | |
683 | ||
ac47786e | 684 | FOR_EACH_VEC_ELT (edge, exits, i, e) |
dea61d92 | 685 | { |
726a989a | 686 | gimple cond = last_stmt (e->src); |
dea61d92 SP |
687 | |
688 | if (cond) | |
726a989a | 689 | VEC_safe_push (gimple, heap, *conds, cond); |
dea61d92 SP |
690 | } |
691 | ||
692 | VEC_free (edge, heap, exits); | |
693 | } | |
694 | ||
695 | /* Add to PARTITION all the exit condition statements for LOOPS | |
696 | together with all their dependent statements determined from | |
697 | RDG. */ | |
698 | ||
699 | static void | |
c61f8985 | 700 | rdg_flag_loop_exits (struct graph *rdg, bitmap loops, partition_t partition, |
dea61d92 SP |
701 | bitmap processed, bool *part_has_writes) |
702 | { | |
703 | unsigned i; | |
704 | bitmap_iterator bi; | |
726a989a | 705 | VEC (gimple, heap) *conds = VEC_alloc (gimple, heap, 3); |
dea61d92 SP |
706 | |
707 | EXECUTE_IF_SET_IN_BITMAP (loops, 0, i, bi) | |
708 | collect_condition_stmts (get_loop (i), &conds); | |
709 | ||
726a989a | 710 | while (!VEC_empty (gimple, conds)) |
dea61d92 | 711 | { |
726a989a | 712 | gimple cond = VEC_pop (gimple, conds); |
dea61d92 SP |
713 | int v = rdg_vertex_for_stmt (rdg, cond); |
714 | bitmap new_loops = BITMAP_ALLOC (NULL); | |
715 | ||
716 | if (!already_processed_vertex_p (processed, v)) | |
717 | rdg_flag_vertex_and_dependent (rdg, v, partition, new_loops, processed, | |
718 | part_has_writes); | |
719 | ||
720 | EXECUTE_IF_SET_IN_BITMAP (new_loops, 0, i, bi) | |
fcaa4ca4 NF |
721 | if (bitmap_set_bit (loops, i)) |
722 | collect_condition_stmts (get_loop (i), &conds); | |
dea61d92 SP |
723 | |
724 | BITMAP_FREE (new_loops); | |
725 | } | |
01be8516 SP |
726 | |
727 | VEC_free (gimple, heap, conds); | |
dea61d92 SP |
728 | } |
729 | ||
dea61d92 SP |
730 | /* Returns a bitmap in which all the statements needed for computing |
731 | the strongly connected component C of the RDG are flagged, also | |
732 | including the loop exit conditions. */ | |
733 | ||
c61f8985 | 734 | static partition_t |
dea61d92 | 735 | build_rdg_partition_for_component (struct graph *rdg, rdgc c, |
cfee318d | 736 | bool *part_has_writes) |
dea61d92 SP |
737 | { |
738 | int i, v; | |
c61f8985 | 739 | partition_t partition = partition_alloc (NULL); |
dea61d92 SP |
740 | bitmap loops = BITMAP_ALLOC (NULL); |
741 | bitmap processed = BITMAP_ALLOC (NULL); | |
742 | ||
ac47786e | 743 | FOR_EACH_VEC_ELT (int, c->vertices, i, v) |
dea61d92 SP |
744 | if (!already_processed_vertex_p (processed, v)) |
745 | rdg_flag_vertex_and_dependent (rdg, v, partition, loops, processed, | |
746 | part_has_writes); | |
747 | ||
dea61d92 SP |
748 | rdg_flag_loop_exits (rdg, loops, partition, processed, part_has_writes); |
749 | ||
750 | BITMAP_FREE (processed); | |
751 | BITMAP_FREE (loops); | |
752 | return partition; | |
753 | } | |
754 | ||
755 | /* Free memory for COMPONENTS. */ | |
756 | ||
757 | static void | |
758 | free_rdg_components (VEC (rdgc, heap) *components) | |
759 | { | |
760 | int i; | |
761 | rdgc x; | |
762 | ||
ac47786e | 763 | FOR_EACH_VEC_ELT (rdgc, components, i, x) |
dea61d92 SP |
764 | { |
765 | VEC_free (int, heap, x->vertices); | |
766 | free (x); | |
767 | } | |
01be8516 SP |
768 | |
769 | VEC_free (rdgc, heap, components); | |
dea61d92 SP |
770 | } |
771 | ||
772 | /* Build the COMPONENTS vector with the strongly connected components | |
773 | of RDG in which the STARTING_VERTICES occur. */ | |
774 | ||
775 | static void | |
b8698a0f | 776 | rdg_build_components (struct graph *rdg, VEC (int, heap) *starting_vertices, |
dea61d92 SP |
777 | VEC (rdgc, heap) **components) |
778 | { | |
779 | int i, v; | |
780 | bitmap saved_components = BITMAP_ALLOC (NULL); | |
781 | int n_components = graphds_scc (rdg, NULL); | |
782 | VEC (int, heap) **all_components = XNEWVEC (VEC (int, heap) *, n_components); | |
783 | ||
784 | for (i = 0; i < n_components; i++) | |
785 | all_components[i] = VEC_alloc (int, heap, 3); | |
786 | ||
787 | for (i = 0; i < rdg->n_vertices; i++) | |
788 | VEC_safe_push (int, heap, all_components[rdg->vertices[i].component], i); | |
789 | ||
ac47786e | 790 | FOR_EACH_VEC_ELT (int, starting_vertices, i, v) |
dea61d92 SP |
791 | { |
792 | int c = rdg->vertices[v].component; | |
793 | ||
fcaa4ca4 | 794 | if (bitmap_set_bit (saved_components, c)) |
dea61d92 SP |
795 | { |
796 | rdgc x = XCNEW (struct rdg_component); | |
797 | x->num = c; | |
798 | x->vertices = all_components[c]; | |
799 | ||
800 | VEC_safe_push (rdgc, heap, *components, x); | |
dea61d92 SP |
801 | } |
802 | } | |
803 | ||
804 | for (i = 0; i < n_components; i++) | |
805 | if (!bitmap_bit_p (saved_components, i)) | |
806 | VEC_free (int, heap, all_components[i]); | |
807 | ||
808 | free (all_components); | |
809 | BITMAP_FREE (saved_components); | |
810 | } | |
811 | ||
30d55936 RG |
812 | /* Classifies the builtin kind we can generate for PARTITION of RDG and LOOP. |
813 | For the moment we detect only the memset zero pattern. */ | |
cfee318d | 814 | |
30d55936 RG |
815 | static void |
816 | classify_partition (loop_p loop, struct graph *rdg, partition_t partition) | |
cfee318d | 817 | { |
cfee318d | 818 | bitmap_iterator bi; |
30d55936 RG |
819 | unsigned i; |
820 | tree nb_iter; | |
821 | ||
822 | partition->kind = PKIND_NORMAL; | |
823 | partition->main_stmt = NULL; | |
824 | ||
c014f6f5 RG |
825 | if (!flag_tree_loop_distribute_patterns) |
826 | return; | |
827 | ||
30d55936 RG |
828 | /* Perform general partition disqualification for builtins. */ |
829 | nb_iter = number_of_exit_cond_executions (loop); | |
830 | if (!nb_iter || nb_iter == chrec_dont_know) | |
831 | return; | |
cfee318d | 832 | |
c61f8985 | 833 | EXECUTE_IF_SET_IN_BITMAP (partition->stmts, 0, i, bi) |
30d55936 RG |
834 | { |
835 | gimple stmt = RDG_STMT (rdg, i); | |
836 | ||
837 | if (gimple_has_volatile_ops (stmt)) | |
838 | return; | |
cfee318d | 839 | |
30d55936 RG |
840 | /* If the stmt has uses outside of the loop fail. |
841 | ??? If the stmt is generated in another partition that | |
842 | is not created as builtin we can ignore this. */ | |
9ca86fc3 | 843 | if (stmt_has_scalar_dependences_outside_loop (loop, stmt)) |
30d55936 RG |
844 | { |
845 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
846 | fprintf (dump_file, "not generating builtin, partition has " | |
847 | "scalar uses outside of the loop\n"); | |
848 | return; | |
849 | } | |
850 | } | |
851 | ||
852 | /* Detect memset. */ | |
853 | EXECUTE_IF_SET_IN_BITMAP (partition->stmts, 0, i, bi) | |
854 | { | |
855 | gimple stmt = RDG_STMT (rdg, i); | |
856 | ||
857 | if (gimple_code (stmt) == GIMPLE_PHI) | |
858 | continue; | |
859 | ||
860 | /* Any scalar stmts are ok. */ | |
861 | if (!gimple_vuse (stmt)) | |
862 | continue; | |
863 | ||
864 | /* Exactly one store. */ | |
865 | if (gimple_assign_single_p (stmt) | |
866 | && !is_gimple_reg (gimple_assign_lhs (stmt))) | |
867 | { | |
868 | if (partition->main_stmt != NULL) | |
869 | return; | |
870 | partition->main_stmt = stmt; | |
871 | } | |
872 | else | |
873 | return; | |
874 | } | |
875 | ||
876 | if (partition->main_stmt != NULL | |
877 | && stmt_with_adjacent_zero_store_dr_p (partition->main_stmt)) | |
878 | partition->kind = PKIND_MEMSET; | |
cfee318d SP |
879 | } |
880 | ||
881 | /* Returns true when PARTITION1 and PARTITION2 have similar memory | |
882 | accesses in RDG. */ | |
883 | ||
884 | static bool | |
c61f8985 RG |
885 | similar_memory_accesses (struct graph *rdg, partition_t partition1, |
886 | partition_t partition2) | |
cfee318d SP |
887 | { |
888 | unsigned i, j; | |
889 | bitmap_iterator bi, bj; | |
890 | ||
c61f8985 | 891 | EXECUTE_IF_SET_IN_BITMAP (partition1->stmts, 0, i, bi) |
cfee318d SP |
892 | if (RDG_MEM_WRITE_STMT (rdg, i) |
893 | || RDG_MEM_READS_STMT (rdg, i)) | |
c61f8985 | 894 | EXECUTE_IF_SET_IN_BITMAP (partition2->stmts, 0, j, bj) |
cfee318d SP |
895 | if (RDG_MEM_WRITE_STMT (rdg, j) |
896 | || RDG_MEM_READS_STMT (rdg, j)) | |
897 | if (rdg_has_similar_memory_accesses (rdg, i, j)) | |
898 | return true; | |
899 | ||
900 | return false; | |
901 | } | |
902 | ||
dea61d92 SP |
903 | /* Aggregate several components into a useful partition that is |
904 | registered in the PARTITIONS vector. Partitions will be | |
905 | distributed in different loops. */ | |
906 | ||
907 | static void | |
908 | rdg_build_partitions (struct graph *rdg, VEC (rdgc, heap) *components, | |
909 | VEC (int, heap) **other_stores, | |
c61f8985 | 910 | VEC (partition_t, heap) **partitions, bitmap processed) |
dea61d92 SP |
911 | { |
912 | int i; | |
913 | rdgc x; | |
c61f8985 | 914 | partition_t partition = partition_alloc (NULL); |
dea61d92 | 915 | |
ac47786e | 916 | FOR_EACH_VEC_ELT (rdgc, components, i, x) |
dea61d92 | 917 | { |
c61f8985 | 918 | partition_t np; |
dea61d92 SP |
919 | bool part_has_writes = false; |
920 | int v = VEC_index (int, x->vertices, 0); | |
b8698a0f | 921 | |
dea61d92 SP |
922 | if (bitmap_bit_p (processed, v)) |
923 | continue; | |
b8698a0f | 924 | |
cfee318d | 925 | np = build_rdg_partition_for_component (rdg, x, &part_has_writes); |
c61f8985 RG |
926 | bitmap_ior_into (partition->stmts, np->stmts); |
927 | bitmap_ior_into (processed, np->stmts); | |
928 | partition_free (np); | |
dea61d92 SP |
929 | |
930 | if (part_has_writes) | |
931 | { | |
932 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
933 | { | |
934 | fprintf (dump_file, "ldist useful partition:\n"); | |
c61f8985 | 935 | dump_bitmap (dump_file, partition->stmts); |
dea61d92 SP |
936 | } |
937 | ||
c61f8985 RG |
938 | VEC_safe_push (partition_t, heap, *partitions, partition); |
939 | partition = partition_alloc (NULL); | |
dea61d92 SP |
940 | } |
941 | } | |
942 | ||
943 | /* Add the nodes from the RDG that were not marked as processed, and | |
944 | that are used outside the current loop. These are scalar | |
945 | computations that are not yet part of previous partitions. */ | |
946 | for (i = 0; i < rdg->n_vertices; i++) | |
947 | if (!bitmap_bit_p (processed, i) | |
948 | && rdg_defs_used_in_other_loops_p (rdg, i)) | |
949 | VEC_safe_push (int, heap, *other_stores, i); | |
950 | ||
951 | /* If there are still statements left in the OTHER_STORES array, | |
952 | create other components and partitions with these stores and | |
953 | their dependences. */ | |
954 | if (VEC_length (int, *other_stores) > 0) | |
955 | { | |
956 | VEC (rdgc, heap) *comps = VEC_alloc (rdgc, heap, 3); | |
957 | VEC (int, heap) *foo = VEC_alloc (int, heap, 3); | |
958 | ||
959 | rdg_build_components (rdg, *other_stores, &comps); | |
960 | rdg_build_partitions (rdg, comps, &foo, partitions, processed); | |
961 | ||
962 | VEC_free (int, heap, foo); | |
963 | free_rdg_components (comps); | |
964 | } | |
965 | ||
966 | /* If there is something left in the last partition, save it. */ | |
c61f8985 RG |
967 | if (bitmap_count_bits (partition->stmts) > 0) |
968 | VEC_safe_push (partition_t, heap, *partitions, partition); | |
dea61d92 | 969 | else |
c61f8985 | 970 | partition_free (partition); |
dea61d92 SP |
971 | } |
972 | ||
973 | /* Dump to FILE the PARTITIONS. */ | |
974 | ||
975 | static void | |
c61f8985 | 976 | dump_rdg_partitions (FILE *file, VEC (partition_t, heap) *partitions) |
dea61d92 SP |
977 | { |
978 | int i; | |
c61f8985 | 979 | partition_t partition; |
dea61d92 | 980 | |
c61f8985 RG |
981 | FOR_EACH_VEC_ELT (partition_t, partitions, i, partition) |
982 | debug_bitmap_file (file, partition->stmts); | |
dea61d92 SP |
983 | } |
984 | ||
985 | /* Debug PARTITIONS. */ | |
c61f8985 | 986 | extern void debug_rdg_partitions (VEC (partition_t, heap) *); |
dea61d92 | 987 | |
24e47c76 | 988 | DEBUG_FUNCTION void |
c61f8985 | 989 | debug_rdg_partitions (VEC (partition_t, heap) *partitions) |
dea61d92 SP |
990 | { |
991 | dump_rdg_partitions (stderr, partitions); | |
992 | } | |
993 | ||
2b8aee8e SP |
994 | /* Returns the number of read and write operations in the RDG. */ |
995 | ||
996 | static int | |
997 | number_of_rw_in_rdg (struct graph *rdg) | |
998 | { | |
999 | int i, res = 0; | |
1000 | ||
1001 | for (i = 0; i < rdg->n_vertices; i++) | |
1002 | { | |
1003 | if (RDG_MEM_WRITE_STMT (rdg, i)) | |
1004 | ++res; | |
1005 | ||
1006 | if (RDG_MEM_READS_STMT (rdg, i)) | |
1007 | ++res; | |
1008 | } | |
1009 | ||
1010 | return res; | |
1011 | } | |
1012 | ||
1013 | /* Returns the number of read and write operations in a PARTITION of | |
1014 | the RDG. */ | |
1015 | ||
1016 | static int | |
c61f8985 | 1017 | number_of_rw_in_partition (struct graph *rdg, partition_t partition) |
2b8aee8e SP |
1018 | { |
1019 | int res = 0; | |
1020 | unsigned i; | |
1021 | bitmap_iterator ii; | |
1022 | ||
c61f8985 | 1023 | EXECUTE_IF_SET_IN_BITMAP (partition->stmts, 0, i, ii) |
2b8aee8e SP |
1024 | { |
1025 | if (RDG_MEM_WRITE_STMT (rdg, i)) | |
1026 | ++res; | |
1027 | ||
1028 | if (RDG_MEM_READS_STMT (rdg, i)) | |
1029 | ++res; | |
1030 | } | |
1031 | ||
1032 | return res; | |
1033 | } | |
1034 | ||
1035 | /* Returns true when one of the PARTITIONS contains all the read or | |
1036 | write operations of RDG. */ | |
1037 | ||
1038 | static bool | |
c61f8985 | 1039 | partition_contains_all_rw (struct graph *rdg, VEC (partition_t, heap) *partitions) |
2b8aee8e SP |
1040 | { |
1041 | int i; | |
c61f8985 | 1042 | partition_t partition; |
2b8aee8e SP |
1043 | int nrw = number_of_rw_in_rdg (rdg); |
1044 | ||
c61f8985 | 1045 | FOR_EACH_VEC_ELT (partition_t, partitions, i, partition) |
2b8aee8e SP |
1046 | if (nrw == number_of_rw_in_partition (rdg, partition)) |
1047 | return true; | |
1048 | ||
1049 | return false; | |
1050 | } | |
1051 | ||
dea61d92 SP |
1052 | /* Generate code from STARTING_VERTICES in RDG. Returns the number of |
1053 | distributed loops. */ | |
1054 | ||
1055 | static int | |
1056 | ldist_gen (struct loop *loop, struct graph *rdg, | |
1057 | VEC (int, heap) *starting_vertices) | |
1058 | { | |
1059 | int i, nbp; | |
1060 | VEC (rdgc, heap) *components = VEC_alloc (rdgc, heap, 3); | |
c61f8985 | 1061 | VEC (partition_t, heap) *partitions = VEC_alloc (partition_t, heap, 3); |
dea61d92 | 1062 | VEC (int, heap) *other_stores = VEC_alloc (int, heap, 3); |
c61f8985 RG |
1063 | partition_t partition; |
1064 | bitmap processed = BITMAP_ALLOC (NULL); | |
dea61d92 SP |
1065 | |
1066 | remaining_stmts = BITMAP_ALLOC (NULL); | |
1067 | upstream_mem_writes = BITMAP_ALLOC (NULL); | |
1068 | ||
1069 | for (i = 0; i < rdg->n_vertices; i++) | |
1070 | { | |
1071 | bitmap_set_bit (remaining_stmts, i); | |
1072 | ||
1073 | /* Save in OTHER_STORES all the memory writes that are not in | |
1074 | STARTING_VERTICES. */ | |
1075 | if (RDG_MEM_WRITE_STMT (rdg, i)) | |
1076 | { | |
1077 | int v; | |
1078 | unsigned j; | |
1079 | bool found = false; | |
1080 | ||
ac47786e | 1081 | FOR_EACH_VEC_ELT (int, starting_vertices, j, v) |
dea61d92 SP |
1082 | if (i == v) |
1083 | { | |
1084 | found = true; | |
1085 | break; | |
1086 | } | |
1087 | ||
1088 | if (!found) | |
1089 | VEC_safe_push (int, heap, other_stores, i); | |
1090 | } | |
1091 | } | |
1092 | ||
1093 | mark_nodes_having_upstream_mem_writes (rdg); | |
1094 | rdg_build_components (rdg, starting_vertices, &components); | |
1095 | rdg_build_partitions (rdg, components, &other_stores, &partitions, | |
1096 | processed); | |
1097 | BITMAP_FREE (processed); | |
dea61d92 | 1098 | |
30d55936 RG |
1099 | FOR_EACH_VEC_ELT (partition_t, partitions, i, partition) |
1100 | classify_partition (loop, rdg, partition); | |
1101 | ||
c014f6f5 RG |
1102 | /* If we are only distributing patterns fuse all partitions that |
1103 | were not properly classified as builtins. Else fuse partitions | |
1104 | with similar memory accesses. */ | |
1105 | if (!flag_tree_loop_distribution) | |
1106 | { | |
1107 | partition_t into; | |
1108 | for (i = 0; VEC_iterate (partition_t, partitions, i, into); ++i) | |
1109 | if (!partition_builtin_p (into)) | |
1110 | break; | |
1111 | for (++i; VEC_iterate (partition_t, partitions, i, partition); ++i) | |
1112 | if (!partition_builtin_p (partition)) | |
1113 | { | |
1114 | bitmap_ior_into (into->stmts, partition->stmts); | |
1115 | VEC_ordered_remove (partition_t, partitions, i); | |
1116 | i--; | |
1117 | } | |
1118 | } | |
1119 | else | |
1120 | { | |
1121 | partition_t into; | |
1122 | int j; | |
1123 | for (i = 0; VEC_iterate (partition_t, partitions, i, into); ++i) | |
1124 | { | |
1125 | if (partition_builtin_p (into)) | |
1126 | continue; | |
1127 | for (j = i + 1; | |
1128 | VEC_iterate (partition_t, partitions, j, partition); ++j) | |
1129 | { | |
1130 | if (!partition_builtin_p (partition) | |
1131 | /* ??? The following is horribly inefficient, | |
1132 | we are re-computing and analyzing data-references | |
1133 | of the stmts in the partitions all the time. */ | |
1134 | && similar_memory_accesses (rdg, into, partition)) | |
1135 | { | |
1136 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1137 | { | |
1138 | fprintf (dump_file, "fusing partitions\n"); | |
1139 | dump_bitmap (dump_file, into->stmts); | |
1140 | dump_bitmap (dump_file, partition->stmts); | |
1141 | fprintf (dump_file, "because they have similar " | |
1142 | "memory accesses\n"); | |
1143 | } | |
1144 | bitmap_ior_into (into->stmts, partition->stmts); | |
1145 | VEC_ordered_remove (partition_t, partitions, j); | |
1146 | j--; | |
1147 | } | |
1148 | } | |
1149 | } | |
1150 | } | |
30d55936 | 1151 | |
c61f8985 | 1152 | nbp = VEC_length (partition_t, partitions); |
a4293fa6 RG |
1153 | if (nbp == 0 |
1154 | || (nbp == 1 | |
30d55936 | 1155 | && !partition_builtin_p (VEC_index (partition_t, partitions, 0))) |
a4293fa6 RG |
1156 | || (nbp > 1 |
1157 | && partition_contains_all_rw (rdg, partitions))) | |
c014f6f5 RG |
1158 | { |
1159 | nbp = 0; | |
1160 | goto ldist_done; | |
1161 | } | |
dea61d92 SP |
1162 | |
1163 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1164 | dump_rdg_partitions (dump_file, partitions); | |
1165 | ||
c61f8985 | 1166 | FOR_EACH_VEC_ELT (partition_t, partitions, i, partition) |
30d55936 | 1167 | generate_code_for_partition (loop, partition, i < nbp - 1); |
dea61d92 | 1168 | |
dea61d92 SP |
1169 | ldist_done: |
1170 | ||
1171 | BITMAP_FREE (remaining_stmts); | |
1172 | BITMAP_FREE (upstream_mem_writes); | |
1173 | ||
c61f8985 RG |
1174 | FOR_EACH_VEC_ELT (partition_t, partitions, i, partition) |
1175 | partition_free (partition); | |
dea61d92 SP |
1176 | |
1177 | VEC_free (int, heap, other_stores); | |
c61f8985 | 1178 | VEC_free (partition_t, heap, partitions); |
dea61d92 SP |
1179 | free_rdg_components (components); |
1180 | return nbp; | |
1181 | } | |
1182 | ||
1183 | /* Distributes the code from LOOP in such a way that producer | |
1184 | statements are placed before consumer statements. When STMTS is | |
1185 | NULL, performs the maximal distribution, if STMTS is not NULL, | |
1186 | tries to separate only these statements from the LOOP's body. | |
1187 | Returns the number of distributed loops. */ | |
1188 | ||
1189 | static int | |
726a989a | 1190 | distribute_loop (struct loop *loop, VEC (gimple, heap) *stmts) |
dea61d92 | 1191 | { |
e96d7dd7 | 1192 | int res = 0; |
dea61d92 | 1193 | struct graph *rdg; |
726a989a | 1194 | gimple s; |
dea61d92 SP |
1195 | unsigned i; |
1196 | VEC (int, heap) *vertices; | |
01be8516 SP |
1197 | VEC (ddr_p, heap) *dependence_relations; |
1198 | VEC (data_reference_p, heap) *datarefs; | |
1199 | VEC (loop_p, heap) *loop_nest; | |
dea61d92 | 1200 | |
01be8516 SP |
1201 | datarefs = VEC_alloc (data_reference_p, heap, 10); |
1202 | dependence_relations = VEC_alloc (ddr_p, heap, 100); | |
1203 | loop_nest = VEC_alloc (loop_p, heap, 3); | |
1204 | rdg = build_rdg (loop, &loop_nest, &dependence_relations, &datarefs); | |
dea61d92 SP |
1205 | |
1206 | if (!rdg) | |
1207 | { | |
1208 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1209 | fprintf (dump_file, | |
1210 | "FIXME: Loop %d not distributed: failed to build the RDG.\n", | |
1211 | loop->num); | |
1212 | ||
01be8516 SP |
1213 | free_dependence_relations (dependence_relations); |
1214 | free_data_refs (datarefs); | |
1215 | VEC_free (loop_p, heap, loop_nest); | |
dea61d92 SP |
1216 | return res; |
1217 | } | |
1218 | ||
1219 | vertices = VEC_alloc (int, heap, 3); | |
1220 | ||
1221 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1222 | dump_rdg (dump_file, rdg); | |
1223 | ||
ac47786e | 1224 | FOR_EACH_VEC_ELT (gimple, stmts, i, s) |
dea61d92 SP |
1225 | { |
1226 | int v = rdg_vertex_for_stmt (rdg, s); | |
1227 | ||
1228 | if (v >= 0) | |
1229 | { | |
1230 | VEC_safe_push (int, heap, vertices, v); | |
1231 | ||
1232 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1233 | fprintf (dump_file, | |
1234 | "ldist asked to generate code for vertex %d\n", v); | |
1235 | } | |
1236 | } | |
1237 | ||
1238 | res = ldist_gen (loop, rdg, vertices); | |
1239 | VEC_free (int, heap, vertices); | |
1240 | free_rdg (rdg); | |
01be8516 SP |
1241 | free_dependence_relations (dependence_relations); |
1242 | free_data_refs (datarefs); | |
1243 | VEC_free (loop_p, heap, loop_nest); | |
dea61d92 SP |
1244 | return res; |
1245 | } | |
1246 | ||
1247 | /* Distribute all loops in the current function. */ | |
1248 | ||
1249 | static unsigned int | |
1250 | tree_loop_distribution (void) | |
1251 | { | |
1252 | struct loop *loop; | |
1253 | loop_iterator li; | |
c014f6f5 | 1254 | bool changed = false; |
dea61d92 | 1255 | |
c014f6f5 RG |
1256 | /* We can at the moment only distribute non-nested loops, thus restrict |
1257 | walking to innermost loops. */ | |
1258 | FOR_EACH_LOOP (li, loop, LI_ONLY_INNERMOST) | |
dea61d92 | 1259 | { |
a3357f7d | 1260 | VEC (gimple, heap) *work_list = NULL; |
0e20c89f | 1261 | int num = loop->num; |
c014f6f5 | 1262 | int nb_generated_loops = 0; |
a3357f7d RG |
1263 | |
1264 | /* If the loop doesn't have a single exit we will fail anyway, | |
1265 | so do that early. */ | |
1266 | if (!single_exit (loop)) | |
1267 | continue; | |
dea61d92 | 1268 | |
c014f6f5 RG |
1269 | /* Only distribute loops with a header and latch for now. */ |
1270 | if (loop->num_nodes > 2) | |
1271 | continue; | |
1272 | ||
1273 | /* -ftree-loop-distribution strictly distributes more but also | |
1274 | enables pattern detection. For now simply distribute all stores | |
1275 | or memset like stores. */ | |
1276 | if (flag_tree_loop_distribution) | |
1277 | stores_from_loop (loop, &work_list); | |
1278 | else if (flag_tree_loop_distribute_patterns) | |
1279 | stores_zero_from_loop (loop, &work_list); | |
1280 | ||
1281 | if (VEC_length (gimple, work_list) > 0) | |
1282 | nb_generated_loops = distribute_loop (loop, work_list); | |
1283 | ||
1284 | if (nb_generated_loops > 0) | |
1285 | changed = true; | |
dea61d92 SP |
1286 | |
1287 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1288 | { | |
1289 | if (nb_generated_loops > 1) | |
1290 | fprintf (dump_file, "Loop %d distributed: split to %d loops.\n", | |
0e20c89f | 1291 | num, nb_generated_loops); |
dea61d92 | 1292 | else |
0e20c89f | 1293 | fprintf (dump_file, "Loop %d is the same.\n", num); |
dea61d92 SP |
1294 | } |
1295 | ||
726a989a | 1296 | VEC_free (gimple, heap, work_list); |
dea61d92 SP |
1297 | } |
1298 | ||
c014f6f5 RG |
1299 | if (changed) |
1300 | { | |
1301 | mark_sym_for_renaming (gimple_vop (cfun)); | |
1302 | rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa); | |
1303 | } | |
1304 | ||
1305 | #ifdef ENABLE_CHECKING | |
1306 | verify_loop_structure (); | |
1307 | #endif | |
1308 | ||
5006671f | 1309 | return 0; |
dea61d92 SP |
1310 | } |
1311 | ||
1312 | static bool | |
1313 | gate_tree_loop_distribution (void) | |
1314 | { | |
20769d5e SP |
1315 | return flag_tree_loop_distribution |
1316 | || flag_tree_loop_distribute_patterns; | |
dea61d92 SP |
1317 | } |
1318 | ||
8ddbbcae | 1319 | struct gimple_opt_pass pass_loop_distribution = |
dea61d92 | 1320 | { |
8ddbbcae JH |
1321 | { |
1322 | GIMPLE_PASS, | |
dea61d92 SP |
1323 | "ldist", /* name */ |
1324 | gate_tree_loop_distribution, /* gate */ | |
1325 | tree_loop_distribution, /* execute */ | |
1326 | NULL, /* sub */ | |
1327 | NULL, /* next */ | |
1328 | 0, /* static_pass_number */ | |
1329 | TV_TREE_LOOP_DISTRIBUTION, /* tv_id */ | |
1330 | PROP_cfg | PROP_ssa, /* properties_required */ | |
1331 | 0, /* properties_provided */ | |
1332 | 0, /* properties_destroyed */ | |
1333 | 0, /* todo_flags_start */ | |
c07a8cb3 RG |
1334 | TODO_ggc_collect |
1335 | | TODO_verify_ssa /* todo_flags_finish */ | |
8ddbbcae | 1336 | } |
dea61d92 | 1337 | }; |