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c913f08a | 1 | /* High-level loop manipulation functions. |
6ac01510 | 2 | Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc. |
c913f08a ZD |
3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU General Public License as published by the | |
9dcd6f09 | 8 | Free Software Foundation; either version 3, or (at your option) any |
c913f08a ZD |
9 | later version. |
10 | ||
11 | GCC is distributed in the hope that it will be useful, but WITHOUT | |
12 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 | for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
c913f08a ZD |
19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
22 | #include "coretypes.h" | |
23 | #include "tm.h" | |
24 | #include "tree.h" | |
25 | #include "rtl.h" | |
26 | #include "tm_p.h" | |
27 | #include "hard-reg-set.h" | |
28 | #include "basic-block.h" | |
29 | #include "output.h" | |
30 | #include "diagnostic.h" | |
31 | #include "tree-flow.h" | |
32 | #include "tree-dump.h" | |
33 | #include "timevar.h" | |
34 | #include "cfgloop.h" | |
35 | #include "tree-pass.h" | |
36 | #include "cfglayout.h" | |
37 | #include "tree-scalar-evolution.h" | |
17684618 | 38 | #include "params.h" |
7f9bc51b | 39 | #include "tree-inline.h" |
c913f08a | 40 | |
82b85a85 ZD |
41 | /* Creates an induction variable with value BASE + STEP * iteration in LOOP. |
42 | It is expected that neither BASE nor STEP are shared with other expressions | |
43 | (unless the sharing rules allow this). Use VAR as a base var_decl for it | |
44 | (if NULL, a new temporary will be created). The increment will occur at | |
92d2b330 SP |
45 | INCR_POS (after it if AFTER is true, before it otherwise). INCR_POS and |
46 | AFTER can be computed using standard_iv_increment_position. The ssa versions | |
82b85a85 ZD |
47 | of the variable before and after increment will be stored in VAR_BEFORE and |
48 | VAR_AFTER (unless they are NULL). */ | |
49 | ||
50 | void | |
51 | create_iv (tree base, tree step, tree var, struct loop *loop, | |
52 | block_stmt_iterator *incr_pos, bool after, | |
53 | tree *var_before, tree *var_after) | |
54 | { | |
8b11a64c | 55 | tree stmt, initial, step1, stmts; |
82b85a85 ZD |
56 | tree vb, va; |
57 | enum tree_code incr_op = PLUS_EXPR; | |
9be872b7 | 58 | edge pe = loop_preheader_edge (loop); |
82b85a85 ZD |
59 | |
60 | if (!var) | |
61 | { | |
62 | var = create_tmp_var (TREE_TYPE (base), "ivtmp"); | |
f004ab02 | 63 | add_referenced_var (var); |
82b85a85 ZD |
64 | } |
65 | ||
66 | vb = make_ssa_name (var, NULL_TREE); | |
67 | if (var_before) | |
68 | *var_before = vb; | |
69 | va = make_ssa_name (var, NULL_TREE); | |
70 | if (var_after) | |
71 | *var_after = va; | |
72 | ||
73 | /* For easier readability of the created code, produce MINUS_EXPRs | |
74 | when suitable. */ | |
75 | if (TREE_CODE (step) == INTEGER_CST) | |
76 | { | |
77 | if (TYPE_UNSIGNED (TREE_TYPE (step))) | |
78 | { | |
987b67bc | 79 | step1 = fold_build1 (NEGATE_EXPR, TREE_TYPE (step), step); |
82b85a85 ZD |
80 | if (tree_int_cst_lt (step1, step)) |
81 | { | |
82 | incr_op = MINUS_EXPR; | |
83 | step = step1; | |
84 | } | |
85 | } | |
86 | else | |
87 | { | |
6ac01510 ILT |
88 | bool ovf; |
89 | ||
90 | if (!tree_expr_nonnegative_warnv_p (step, &ovf) | |
82b85a85 ZD |
91 | && may_negate_without_overflow_p (step)) |
92 | { | |
93 | incr_op = MINUS_EXPR; | |
987b67bc | 94 | step = fold_build1 (NEGATE_EXPR, TREE_TYPE (step), step); |
82b85a85 ZD |
95 | } |
96 | } | |
97 | } | |
5be014d5 AP |
98 | if (POINTER_TYPE_P (TREE_TYPE (base))) |
99 | { | |
100 | step = fold_convert (sizetype, step); | |
101 | if (incr_op == MINUS_EXPR) | |
102 | step = fold_build1 (NEGATE_EXPR, sizetype, step); | |
103 | incr_op = POINTER_PLUS_EXPR; | |
104 | } | |
9be872b7 ZD |
105 | /* Gimplify the step if necessary. We put the computations in front of the |
106 | loop (i.e. the step should be loop invariant). */ | |
107 | step = force_gimple_operand (step, &stmts, true, var); | |
108 | if (stmts) | |
598ec7bd | 109 | bsi_insert_on_edge_immediate (pe, stmts); |
9be872b7 | 110 | |
939409af RS |
111 | stmt = build_gimple_modify_stmt (va, |
112 | build2 (incr_op, TREE_TYPE (base), | |
113 | vb, step)); | |
82b85a85 ZD |
114 | SSA_NAME_DEF_STMT (va) = stmt; |
115 | if (after) | |
116 | bsi_insert_after (incr_pos, stmt, BSI_NEW_STMT); | |
117 | else | |
118 | bsi_insert_before (incr_pos, stmt, BSI_NEW_STMT); | |
119 | ||
8b11a64c ZD |
120 | initial = force_gimple_operand (base, &stmts, true, var); |
121 | if (stmts) | |
598ec7bd | 122 | bsi_insert_on_edge_immediate (pe, stmts); |
82b85a85 ZD |
123 | |
124 | stmt = create_phi_node (vb, loop->header); | |
125 | SSA_NAME_DEF_STMT (vb) = stmt; | |
d2e398df KH |
126 | add_phi_arg (stmt, initial, loop_preheader_edge (loop)); |
127 | add_phi_arg (stmt, va, loop_latch_edge (loop)); | |
82b85a85 ZD |
128 | } |
129 | ||
c913f08a ZD |
130 | /* Add exit phis for the USE on EXIT. */ |
131 | ||
132 | static void | |
133 | add_exit_phis_edge (basic_block exit, tree use) | |
134 | { | |
135 | tree phi, def_stmt = SSA_NAME_DEF_STMT (use); | |
136 | basic_block def_bb = bb_for_stmt (def_stmt); | |
137 | struct loop *def_loop; | |
138 | edge e; | |
628f6a4e | 139 | edge_iterator ei; |
c913f08a ZD |
140 | |
141 | /* Check that some of the edges entering the EXIT block exits a loop in | |
142 | that USE is defined. */ | |
628f6a4e | 143 | FOR_EACH_EDGE (e, ei, exit->preds) |
c913f08a ZD |
144 | { |
145 | def_loop = find_common_loop (def_bb->loop_father, e->src->loop_father); | |
146 | if (!flow_bb_inside_loop_p (def_loop, e->dest)) | |
147 | break; | |
148 | } | |
149 | ||
150 | if (!e) | |
151 | return; | |
152 | ||
153 | phi = create_phi_node (use, exit); | |
84d65814 | 154 | create_new_def_for (PHI_RESULT (phi), phi, PHI_RESULT_PTR (phi)); |
628f6a4e | 155 | FOR_EACH_EDGE (e, ei, exit->preds) |
d2e398df | 156 | add_phi_arg (phi, use, e); |
c913f08a ZD |
157 | } |
158 | ||
159 | /* Add exit phis for VAR that is used in LIVEIN. | |
160 | Exits of the loops are stored in EXITS. */ | |
161 | ||
162 | static void | |
163 | add_exit_phis_var (tree var, bitmap livein, bitmap exits) | |
164 | { | |
165 | bitmap def; | |
3cd8c58a | 166 | unsigned index; |
c913f08a | 167 | basic_block def_bb = bb_for_stmt (SSA_NAME_DEF_STMT (var)); |
87c476a2 | 168 | bitmap_iterator bi; |
c913f08a | 169 | |
0bca51f0 DN |
170 | if (is_gimple_reg (var)) |
171 | bitmap_clear_bit (livein, def_bb->index); | |
172 | else | |
173 | bitmap_set_bit (livein, def_bb->index); | |
c913f08a | 174 | |
8bdbfff5 | 175 | def = BITMAP_ALLOC (NULL); |
c913f08a ZD |
176 | bitmap_set_bit (def, def_bb->index); |
177 | compute_global_livein (livein, def); | |
8bdbfff5 | 178 | BITMAP_FREE (def); |
c913f08a | 179 | |
87c476a2 ZD |
180 | EXECUTE_IF_AND_IN_BITMAP (exits, livein, 0, index, bi) |
181 | { | |
182 | add_exit_phis_edge (BASIC_BLOCK (index), var); | |
183 | } | |
c913f08a ZD |
184 | } |
185 | ||
186 | /* Add exit phis for the names marked in NAMES_TO_RENAME. | |
187 | Exits of the loops are stored in EXITS. Sets of blocks where the ssa | |
188 | names are used are stored in USE_BLOCKS. */ | |
189 | ||
190 | static void | |
191 | add_exit_phis (bitmap names_to_rename, bitmap *use_blocks, bitmap loop_exits) | |
192 | { | |
193 | unsigned i; | |
87c476a2 | 194 | bitmap_iterator bi; |
c913f08a | 195 | |
87c476a2 | 196 | EXECUTE_IF_SET_IN_BITMAP (names_to_rename, 0, i, bi) |
c913f08a ZD |
197 | { |
198 | add_exit_phis_var (ssa_name (i), use_blocks[i], loop_exits); | |
87c476a2 | 199 | } |
c913f08a ZD |
200 | } |
201 | ||
202 | /* Returns a bitmap of all loop exit edge targets. */ | |
203 | ||
204 | static bitmap | |
205 | get_loops_exits (void) | |
206 | { | |
8bdbfff5 | 207 | bitmap exits = BITMAP_ALLOC (NULL); |
c913f08a ZD |
208 | basic_block bb; |
209 | edge e; | |
628f6a4e | 210 | edge_iterator ei; |
c913f08a ZD |
211 | |
212 | FOR_EACH_BB (bb) | |
213 | { | |
628f6a4e | 214 | FOR_EACH_EDGE (e, ei, bb->preds) |
c913f08a ZD |
215 | if (e->src != ENTRY_BLOCK_PTR |
216 | && !flow_bb_inside_loop_p (e->src->loop_father, bb)) | |
217 | { | |
218 | bitmap_set_bit (exits, bb->index); | |
219 | break; | |
220 | } | |
221 | } | |
222 | ||
223 | return exits; | |
224 | } | |
225 | ||
226 | /* For USE in BB, if it is used outside of the loop it is defined in, | |
227 | mark it for rewrite. Record basic block BB where it is used | |
84d65814 | 228 | to USE_BLOCKS. Record the ssa name index to NEED_PHIS bitmap. */ |
c913f08a ZD |
229 | |
230 | static void | |
84d65814 DN |
231 | find_uses_to_rename_use (basic_block bb, tree use, bitmap *use_blocks, |
232 | bitmap need_phis) | |
c913f08a ZD |
233 | { |
234 | unsigned ver; | |
235 | basic_block def_bb; | |
236 | struct loop *def_loop; | |
237 | ||
238 | if (TREE_CODE (use) != SSA_NAME) | |
239 | return; | |
240 | ||
84d65814 DN |
241 | /* We don't need to keep virtual operands in loop-closed form. */ |
242 | if (!is_gimple_reg (use)) | |
243 | return; | |
244 | ||
c913f08a ZD |
245 | ver = SSA_NAME_VERSION (use); |
246 | def_bb = bb_for_stmt (SSA_NAME_DEF_STMT (use)); | |
247 | if (!def_bb) | |
248 | return; | |
249 | def_loop = def_bb->loop_father; | |
250 | ||
251 | /* If the definition is not inside loop, it is not interesting. */ | |
9ba025a2 | 252 | if (!loop_outer (def_loop)) |
c913f08a ZD |
253 | return; |
254 | ||
255 | if (!use_blocks[ver]) | |
8bdbfff5 | 256 | use_blocks[ver] = BITMAP_ALLOC (NULL); |
c913f08a ZD |
257 | bitmap_set_bit (use_blocks[ver], bb->index); |
258 | ||
84d65814 | 259 | bitmap_set_bit (need_phis, ver); |
c913f08a ZD |
260 | } |
261 | ||
262 | /* For uses in STMT, mark names that are used outside of the loop they are | |
263 | defined to rewrite. Record the set of blocks in that the ssa | |
84d65814 DN |
264 | names are defined to USE_BLOCKS and the ssa names themselves to |
265 | NEED_PHIS. */ | |
c913f08a ZD |
266 | |
267 | static void | |
84d65814 | 268 | find_uses_to_rename_stmt (tree stmt, bitmap *use_blocks, bitmap need_phis) |
c913f08a | 269 | { |
4c124b4c AM |
270 | ssa_op_iter iter; |
271 | tree var; | |
c913f08a ZD |
272 | basic_block bb = bb_for_stmt (stmt); |
273 | ||
38635499 | 274 | FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_USES) |
84d65814 | 275 | find_uses_to_rename_use (bb, var, use_blocks, need_phis); |
c913f08a ZD |
276 | } |
277 | ||
2b271002 ZD |
278 | /* Marks names that are used in BB and outside of the loop they are |
279 | defined in for rewrite. Records the set of blocks in that the ssa | |
84d65814 DN |
280 | names are defined to USE_BLOCKS. Record the SSA names that will |
281 | need exit PHIs in NEED_PHIS. */ | |
c913f08a ZD |
282 | |
283 | static void | |
84d65814 | 284 | find_uses_to_rename_bb (basic_block bb, bitmap *use_blocks, bitmap need_phis) |
c913f08a | 285 | { |
c913f08a | 286 | block_stmt_iterator bsi; |
2b271002 ZD |
287 | edge e; |
288 | edge_iterator ei; | |
c913f08a | 289 | tree phi; |
c913f08a | 290 | |
2b271002 ZD |
291 | FOR_EACH_EDGE (e, ei, bb->succs) |
292 | for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi)) | |
293 | find_uses_to_rename_use (bb, PHI_ARG_DEF_FROM_EDGE (phi, e), | |
84d65814 | 294 | use_blocks, need_phis); |
2b271002 ZD |
295 | |
296 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
84d65814 | 297 | find_uses_to_rename_stmt (bsi_stmt (bsi), use_blocks, need_phis); |
2b271002 ZD |
298 | } |
299 | ||
300 | /* Marks names that are used outside of the loop they are defined in | |
301 | for rewrite. Records the set of blocks in that the ssa | |
302 | names are defined to USE_BLOCKS. If CHANGED_BBS is not NULL, | |
303 | scan only blocks in this set. */ | |
304 | ||
305 | static void | |
84d65814 | 306 | find_uses_to_rename (bitmap changed_bbs, bitmap *use_blocks, bitmap need_phis) |
2b271002 ZD |
307 | { |
308 | basic_block bb; | |
309 | unsigned index; | |
310 | bitmap_iterator bi; | |
c913f08a | 311 | |
84d65814 | 312 | if (changed_bbs && !bitmap_empty_p (changed_bbs)) |
2b271002 ZD |
313 | { |
314 | EXECUTE_IF_SET_IN_BITMAP (changed_bbs, 0, index, bi) | |
315 | { | |
84d65814 | 316 | find_uses_to_rename_bb (BASIC_BLOCK (index), use_blocks, need_phis); |
2b271002 ZD |
317 | } |
318 | } | |
319 | else | |
320 | { | |
321 | FOR_EACH_BB (bb) | |
322 | { | |
84d65814 | 323 | find_uses_to_rename_bb (bb, use_blocks, need_phis); |
2b271002 | 324 | } |
c913f08a ZD |
325 | } |
326 | } | |
327 | ||
328 | /* Rewrites the program into a loop closed ssa form -- i.e. inserts extra | |
329 | phi nodes to ensure that no variable is used outside the loop it is | |
330 | defined in. | |
331 | ||
332 | This strengthening of the basic ssa form has several advantages: | |
333 | ||
334 | 1) Updating it during unrolling/peeling/versioning is trivial, since | |
335 | we do not need to care about the uses outside of the loop. | |
336 | 2) The behavior of all uses of an induction variable is the same. | |
337 | Without this, you need to distinguish the case when the variable | |
338 | is used outside of the loop it is defined in, for example | |
339 | ||
340 | for (i = 0; i < 100; i++) | |
341 | { | |
342 | for (j = 0; j < 100; j++) | |
343 | { | |
344 | k = i + j; | |
345 | use1 (k); | |
346 | } | |
347 | use2 (k); | |
348 | } | |
349 | ||
350 | Looking from the outer loop with the normal SSA form, the first use of k | |
351 | is not well-behaved, while the second one is an induction variable with | |
2b271002 ZD |
352 | base 99 and step 1. |
353 | ||
354 | If CHANGED_BBS is not NULL, we look for uses outside loops only in | |
84d65814 DN |
355 | the basic blocks in this set. |
356 | ||
357 | UPDATE_FLAG is used in the call to update_ssa. See | |
358 | TODO_update_ssa* for documentation. */ | |
c913f08a ZD |
359 | |
360 | void | |
84d65814 | 361 | rewrite_into_loop_closed_ssa (bitmap changed_bbs, unsigned update_flag) |
c913f08a | 362 | { |
c7b852c8 | 363 | bitmap loop_exits; |
c913f08a | 364 | bitmap *use_blocks; |
84d65814 | 365 | unsigned i, old_num_ssa_names; |
c7b852c8 ZD |
366 | bitmap names_to_rename; |
367 | ||
d51157de ZD |
368 | current_loops->state |= LOOP_CLOSED_SSA; |
369 | if (number_of_loops () <= 1) | |
c7b852c8 ZD |
370 | return; |
371 | ||
372 | loop_exits = get_loops_exits (); | |
373 | names_to_rename = BITMAP_ALLOC (NULL); | |
c913f08a | 374 | |
84d65814 DN |
375 | /* If the pass has caused the SSA form to be out-of-date, update it |
376 | now. */ | |
377 | update_ssa (update_flag); | |
c913f08a | 378 | |
84d65814 | 379 | old_num_ssa_names = num_ssa_names; |
5ed6ace5 | 380 | use_blocks = XCNEWVEC (bitmap, old_num_ssa_names); |
c913f08a ZD |
381 | |
382 | /* Find the uses outside loops. */ | |
84d65814 | 383 | find_uses_to_rename (changed_bbs, use_blocks, names_to_rename); |
2b271002 | 384 | |
84d65814 | 385 | /* Add the PHI nodes on exits of the loops for the names we need to |
c913f08a | 386 | rewrite. */ |
c913f08a ZD |
387 | add_exit_phis (names_to_rename, use_blocks, loop_exits); |
388 | ||
84d65814 | 389 | for (i = 0; i < old_num_ssa_names; i++) |
8bdbfff5 | 390 | BITMAP_FREE (use_blocks[i]); |
c913f08a | 391 | free (use_blocks); |
8bdbfff5 NS |
392 | BITMAP_FREE (loop_exits); |
393 | BITMAP_FREE (names_to_rename); | |
c913f08a | 394 | |
84d65814 DN |
395 | /* Fix up all the names found to be used outside their original |
396 | loops. */ | |
397 | update_ssa (TODO_update_ssa); | |
c913f08a ZD |
398 | } |
399 | ||
400 | /* Check invariants of the loop closed ssa form for the USE in BB. */ | |
401 | ||
402 | static void | |
403 | check_loop_closed_ssa_use (basic_block bb, tree use) | |
404 | { | |
405 | tree def; | |
406 | basic_block def_bb; | |
407 | ||
84d65814 | 408 | if (TREE_CODE (use) != SSA_NAME || !is_gimple_reg (use)) |
c913f08a ZD |
409 | return; |
410 | ||
411 | def = SSA_NAME_DEF_STMT (use); | |
412 | def_bb = bb_for_stmt (def); | |
1e128c5f GB |
413 | gcc_assert (!def_bb |
414 | || flow_bb_inside_loop_p (def_bb->loop_father, bb)); | |
c913f08a ZD |
415 | } |
416 | ||
417 | /* Checks invariants of loop closed ssa form in statement STMT in BB. */ | |
418 | ||
419 | static void | |
420 | check_loop_closed_ssa_stmt (basic_block bb, tree stmt) | |
421 | { | |
4c124b4c AM |
422 | ssa_op_iter iter; |
423 | tree var; | |
c913f08a | 424 | |
38635499 | 425 | FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_USES) |
4c124b4c | 426 | check_loop_closed_ssa_use (bb, var); |
c913f08a ZD |
427 | } |
428 | ||
429 | /* Checks that invariants of the loop closed ssa form are preserved. */ | |
430 | ||
431 | void | |
432 | verify_loop_closed_ssa (void) | |
433 | { | |
434 | basic_block bb; | |
435 | block_stmt_iterator bsi; | |
436 | tree phi; | |
437 | unsigned i; | |
438 | ||
d51157de | 439 | if (number_of_loops () <= 1) |
84d65814 DN |
440 | return; |
441 | ||
f430bae8 | 442 | verify_ssa (false); |
c913f08a ZD |
443 | |
444 | FOR_EACH_BB (bb) | |
445 | { | |
bb29d951 | 446 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
c913f08a ZD |
447 | for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++) |
448 | check_loop_closed_ssa_use (PHI_ARG_EDGE (phi, i)->src, | |
449 | PHI_ARG_DEF (phi, i)); | |
450 | ||
451 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
452 | check_loop_closed_ssa_stmt (bb, bsi_stmt (bsi)); | |
453 | } | |
454 | } | |
8b11a64c ZD |
455 | |
456 | /* Split loop exit edge EXIT. The things are a bit complicated by a need to | |
457 | preserve the loop closed ssa form. */ | |
458 | ||
459 | void | |
460 | split_loop_exit_edge (edge exit) | |
461 | { | |
462 | basic_block dest = exit->dest; | |
598ec7bd | 463 | basic_block bb = split_edge (exit); |
7fac6722 | 464 | tree phi, new_phi, new_name, name; |
8b11a64c ZD |
465 | use_operand_p op_p; |
466 | ||
bb29d951 | 467 | for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi)) |
8b11a64c | 468 | { |
c5cbcccf | 469 | op_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, single_succ_edge (bb)); |
8b11a64c | 470 | |
7fac6722 ZD |
471 | name = USE_FROM_PTR (op_p); |
472 | ||
38635499 | 473 | /* If the argument of the PHI node is a constant, we do not need |
7fac6722 ZD |
474 | to keep it inside loop. */ |
475 | if (TREE_CODE (name) != SSA_NAME) | |
476 | continue; | |
477 | ||
478 | /* Otherwise create an auxiliary phi node that will copy the value | |
38635499 | 479 | of the SSA name out of the loop. */ |
7fac6722 | 480 | new_name = duplicate_ssa_name (name, NULL); |
8b11a64c ZD |
481 | new_phi = create_phi_node (new_name, bb); |
482 | SSA_NAME_DEF_STMT (new_name) = new_phi; | |
d2e398df | 483 | add_phi_arg (new_phi, name, exit); |
8b11a64c ZD |
484 | SET_USE (op_p, new_name); |
485 | } | |
486 | } | |
487 | ||
8b11a64c ZD |
488 | /* Returns the basic block in that statements should be emitted for induction |
489 | variables incremented at the end of the LOOP. */ | |
490 | ||
491 | basic_block | |
492 | ip_end_pos (struct loop *loop) | |
493 | { | |
494 | return loop->latch; | |
495 | } | |
496 | ||
497 | /* Returns the basic block in that statements should be emitted for induction | |
498 | variables incremented just before exit condition of a LOOP. */ | |
499 | ||
500 | basic_block | |
501 | ip_normal_pos (struct loop *loop) | |
502 | { | |
503 | tree last; | |
504 | basic_block bb; | |
505 | edge exit; | |
506 | ||
c5cbcccf | 507 | if (!single_pred_p (loop->latch)) |
8b11a64c ZD |
508 | return NULL; |
509 | ||
c5cbcccf | 510 | bb = single_pred (loop->latch); |
8b11a64c | 511 | last = last_stmt (bb); |
ae2cf11b RG |
512 | if (!last |
513 | || TREE_CODE (last) != COND_EXPR) | |
8b11a64c ZD |
514 | return NULL; |
515 | ||
628f6a4e | 516 | exit = EDGE_SUCC (bb, 0); |
8b11a64c | 517 | if (exit->dest == loop->latch) |
628f6a4e | 518 | exit = EDGE_SUCC (bb, 1); |
8b11a64c ZD |
519 | |
520 | if (flow_bb_inside_loop_p (loop, exit->dest)) | |
521 | return NULL; | |
522 | ||
523 | return bb; | |
524 | } | |
525 | ||
526 | /* Stores the standard position for induction variable increment in LOOP | |
527 | (just before the exit condition if it is available and latch block is empty, | |
528 | end of the latch block otherwise) to BSI. INSERT_AFTER is set to true if | |
529 | the increment should be inserted after *BSI. */ | |
530 | ||
531 | void | |
532 | standard_iv_increment_position (struct loop *loop, block_stmt_iterator *bsi, | |
533 | bool *insert_after) | |
534 | { | |
535 | basic_block bb = ip_normal_pos (loop), latch = ip_end_pos (loop); | |
536 | tree last = last_stmt (latch); | |
537 | ||
538 | if (!bb | |
539 | || (last && TREE_CODE (last) != LABEL_EXPR)) | |
540 | { | |
541 | *bsi = bsi_last (latch); | |
542 | *insert_after = true; | |
543 | } | |
544 | else | |
545 | { | |
546 | *bsi = bsi_last (bb); | |
547 | *insert_after = false; | |
548 | } | |
549 | } | |
92fc4a2f ZD |
550 | |
551 | /* Copies phi node arguments for duplicated blocks. The index of the first | |
552 | duplicated block is FIRST_NEW_BLOCK. */ | |
553 | ||
554 | static void | |
555 | copy_phi_node_args (unsigned first_new_block) | |
556 | { | |
557 | unsigned i; | |
558 | ||
559 | for (i = first_new_block; i < (unsigned) last_basic_block; i++) | |
6580ee77 | 560 | BASIC_BLOCK (i)->flags |= BB_DUPLICATED; |
92fc4a2f ZD |
561 | |
562 | for (i = first_new_block; i < (unsigned) last_basic_block; i++) | |
563 | add_phi_args_after_copy_bb (BASIC_BLOCK (i)); | |
564 | ||
565 | for (i = first_new_block; i < (unsigned) last_basic_block; i++) | |
6580ee77 | 566 | BASIC_BLOCK (i)->flags &= ~BB_DUPLICATED; |
92fc4a2f ZD |
567 | } |
568 | ||
92fc4a2f | 569 | |
84d65814 DN |
570 | /* The same as cfgloopmanip.c:duplicate_loop_to_header_edge, but also |
571 | updates the PHI nodes at start of the copied region. In order to | |
572 | achieve this, only loops whose exits all lead to the same location | |
573 | are handled. | |
92fc4a2f | 574 | |
84d65814 DN |
575 | Notice that we do not completely update the SSA web after |
576 | duplication. The caller is responsible for calling update_ssa | |
577 | after the loop has been duplicated. */ | |
92fc4a2f ZD |
578 | |
579 | bool | |
580 | tree_duplicate_loop_to_header_edge (struct loop *loop, edge e, | |
92fc4a2f | 581 | unsigned int ndupl, sbitmap wont_exit, |
ee8c1b05 ZD |
582 | edge orig, VEC (edge, heap) **to_remove, |
583 | int flags) | |
92fc4a2f ZD |
584 | { |
585 | unsigned first_new_block; | |
92fc4a2f | 586 | |
d73be268 | 587 | if (!(current_loops->state & LOOPS_HAVE_SIMPLE_LATCHES)) |
92fc4a2f | 588 | return false; |
d73be268 | 589 | if (!(current_loops->state & LOOPS_HAVE_PREHEADERS)) |
92fc4a2f ZD |
590 | return false; |
591 | ||
592 | #ifdef ENABLE_CHECKING | |
593 | verify_loop_closed_ssa (); | |
594 | #endif | |
595 | ||
92fc4a2f | 596 | first_new_block = last_basic_block; |
d73be268 | 597 | if (!duplicate_loop_to_header_edge (loop, e, ndupl, wont_exit, |
ee8c1b05 | 598 | orig, to_remove, flags)) |
92fc4a2f ZD |
599 | return false; |
600 | ||
601 | /* Readd the removed phi args for e. */ | |
71882046 | 602 | flush_pending_stmts (e); |
92fc4a2f ZD |
603 | |
604 | /* Copy the phi node arguments. */ | |
605 | copy_phi_node_args (first_new_block); | |
606 | ||
92fc4a2f | 607 | scev_reset (); |
92fc4a2f ZD |
608 | |
609 | return true; | |
610 | } | |
17684618 | 611 | |
17684618 ZD |
612 | /* Returns true if we can unroll LOOP FACTOR times. Number |
613 | of iterations of the loop is returned in NITER. */ | |
614 | ||
615 | bool | |
616 | can_unroll_loop_p (struct loop *loop, unsigned factor, | |
617 | struct tree_niter_desc *niter) | |
618 | { | |
619 | edge exit; | |
620 | ||
621 | /* Check whether unrolling is possible. We only want to unroll loops | |
622 | for that we are able to determine number of iterations. We also | |
623 | want to split the extra iterations of the loop from its end, | |
624 | therefore we require that the loop has precisely one | |
625 | exit. */ | |
626 | ||
627 | exit = single_dom_exit (loop); | |
628 | if (!exit) | |
629 | return false; | |
630 | ||
631 | if (!number_of_iterations_exit (loop, exit, niter, false) | |
bf8dbe38 ZD |
632 | || niter->cmp == ERROR_MARK |
633 | /* Scalar evolutions analysis might have copy propagated | |
634 | the abnormal ssa names into these expressions, hence | |
2f8e468b | 635 | emitting the computations based on them during loop |
bf8dbe38 ZD |
636 | unrolling might create overlapping life ranges for |
637 | them, and failures in out-of-ssa. */ | |
638 | || contains_abnormal_ssa_name_p (niter->may_be_zero) | |
639 | || contains_abnormal_ssa_name_p (niter->control.base) | |
640 | || contains_abnormal_ssa_name_p (niter->control.step) | |
641 | || contains_abnormal_ssa_name_p (niter->bound)) | |
17684618 ZD |
642 | return false; |
643 | ||
644 | /* And of course, we must be able to duplicate the loop. */ | |
645 | if (!can_duplicate_loop_p (loop)) | |
646 | return false; | |
647 | ||
648 | /* The final loop should be small enough. */ | |
7f9bc51b | 649 | if (tree_num_loop_insns (loop, &eni_size_weights) * factor |
17684618 ZD |
650 | > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS)) |
651 | return false; | |
652 | ||
653 | return true; | |
654 | } | |
655 | ||
656 | /* Determines the conditions that control execution of LOOP unrolled FACTOR | |
657 | times. DESC is number of iterations of LOOP. ENTER_COND is set to | |
658 | condition that must be true if the main loop can be entered. | |
659 | EXIT_BASE, EXIT_STEP, EXIT_CMP and EXIT_BOUND are set to values describing | |
660 | how the exit from the unrolled loop should be controlled. */ | |
661 | ||
662 | static void | |
663 | determine_exit_conditions (struct loop *loop, struct tree_niter_desc *desc, | |
664 | unsigned factor, tree *enter_cond, | |
665 | tree *exit_base, tree *exit_step, | |
666 | enum tree_code *exit_cmp, tree *exit_bound) | |
667 | { | |
668 | tree stmts; | |
669 | tree base = desc->control.base; | |
670 | tree step = desc->control.step; | |
671 | tree bound = desc->bound; | |
d24a32a1 | 672 | tree type = TREE_TYPE (step); |
17684618 ZD |
673 | tree bigstep, delta; |
674 | tree min = lower_bound_in_type (type, type); | |
675 | tree max = upper_bound_in_type (type, type); | |
676 | enum tree_code cmp = desc->cmp; | |
677 | tree cond = boolean_true_node, assum; | |
678 | ||
d24a32a1 ZD |
679 | /* For pointers, do the arithmetics in the type of step (sizetype). */ |
680 | base = fold_convert (type, base); | |
681 | bound = fold_convert (type, bound); | |
682 | ||
17684618 ZD |
683 | *enter_cond = boolean_false_node; |
684 | *exit_base = NULL_TREE; | |
685 | *exit_step = NULL_TREE; | |
686 | *exit_cmp = ERROR_MARK; | |
687 | *exit_bound = NULL_TREE; | |
688 | gcc_assert (cmp != ERROR_MARK); | |
689 | ||
690 | /* We only need to be correct when we answer question | |
691 | "Do at least FACTOR more iterations remain?" in the unrolled loop. | |
692 | Thus, transforming BASE + STEP * i <> BOUND to | |
693 | BASE + STEP * i < BOUND is ok. */ | |
694 | if (cmp == NE_EXPR) | |
695 | { | |
696 | if (tree_int_cst_sign_bit (step)) | |
697 | cmp = GT_EXPR; | |
698 | else | |
699 | cmp = LT_EXPR; | |
700 | } | |
701 | else if (cmp == LT_EXPR) | |
702 | { | |
703 | gcc_assert (!tree_int_cst_sign_bit (step)); | |
704 | } | |
705 | else if (cmp == GT_EXPR) | |
706 | { | |
707 | gcc_assert (tree_int_cst_sign_bit (step)); | |
708 | } | |
709 | else | |
710 | gcc_unreachable (); | |
711 | ||
712 | /* The main body of the loop may be entered iff: | |
713 | ||
714 | 1) desc->may_be_zero is false. | |
715 | 2) it is possible to check that there are at least FACTOR iterations | |
716 | of the loop, i.e., BOUND - step * FACTOR does not overflow. | |
717 | 3) # of iterations is at least FACTOR */ | |
718 | ||
6e682d7e | 719 | if (!integer_zerop (desc->may_be_zero)) |
17684618 ZD |
720 | cond = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, |
721 | invert_truthvalue (desc->may_be_zero), | |
722 | cond); | |
723 | ||
724 | bigstep = fold_build2 (MULT_EXPR, type, step, | |
725 | build_int_cst_type (type, factor)); | |
726 | delta = fold_build2 (MINUS_EXPR, type, bigstep, step); | |
727 | if (cmp == LT_EXPR) | |
728 | assum = fold_build2 (GE_EXPR, boolean_type_node, | |
729 | bound, | |
730 | fold_build2 (PLUS_EXPR, type, min, delta)); | |
731 | else | |
732 | assum = fold_build2 (LE_EXPR, boolean_type_node, | |
733 | bound, | |
734 | fold_build2 (PLUS_EXPR, type, max, delta)); | |
735 | cond = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, assum, cond); | |
736 | ||
737 | bound = fold_build2 (MINUS_EXPR, type, bound, delta); | |
738 | assum = fold_build2 (cmp, boolean_type_node, base, bound); | |
739 | cond = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, assum, cond); | |
740 | ||
741 | cond = force_gimple_operand (unshare_expr (cond), &stmts, false, NULL_TREE); | |
742 | if (stmts) | |
598ec7bd | 743 | bsi_insert_on_edge_immediate (loop_preheader_edge (loop), stmts); |
17684618 ZD |
744 | /* cond now may be a gimple comparison, which would be OK, but also any |
745 | other gimple rhs (say a && b). In this case we need to force it to | |
746 | operand. */ | |
747 | if (!is_gimple_condexpr (cond)) | |
748 | { | |
749 | cond = force_gimple_operand (cond, &stmts, true, NULL_TREE); | |
750 | if (stmts) | |
598ec7bd | 751 | bsi_insert_on_edge_immediate (loop_preheader_edge (loop), stmts); |
17684618 ZD |
752 | } |
753 | *enter_cond = cond; | |
754 | ||
755 | base = force_gimple_operand (unshare_expr (base), &stmts, true, NULL_TREE); | |
756 | if (stmts) | |
598ec7bd | 757 | bsi_insert_on_edge_immediate (loop_preheader_edge (loop), stmts); |
17684618 ZD |
758 | bound = force_gimple_operand (unshare_expr (bound), &stmts, true, NULL_TREE); |
759 | if (stmts) | |
598ec7bd | 760 | bsi_insert_on_edge_immediate (loop_preheader_edge (loop), stmts); |
17684618 ZD |
761 | |
762 | *exit_base = base; | |
763 | *exit_step = bigstep; | |
764 | *exit_cmp = cmp; | |
765 | *exit_bound = bound; | |
766 | } | |
767 | ||
14fa2cc0 ZD |
768 | /* Scales the frequencies of all basic blocks in LOOP that are strictly |
769 | dominated by BB by NUM/DEN. */ | |
770 | ||
771 | static void | |
772 | scale_dominated_blocks_in_loop (struct loop *loop, basic_block bb, | |
773 | int num, int den) | |
774 | { | |
775 | basic_block son; | |
776 | ||
777 | if (den == 0) | |
778 | return; | |
779 | ||
780 | for (son = first_dom_son (CDI_DOMINATORS, bb); | |
781 | son; | |
782 | son = next_dom_son (CDI_DOMINATORS, son)) | |
783 | { | |
784 | if (!flow_bb_inside_loop_p (loop, son)) | |
785 | continue; | |
786 | scale_bbs_frequencies_int (&son, 1, num, den); | |
787 | scale_dominated_blocks_in_loop (loop, son, num, den); | |
788 | } | |
789 | } | |
790 | ||
d73be268 ZD |
791 | /* Unroll LOOP FACTOR times. DESC describes number of iterations of LOOP. |
792 | EXIT is the exit of the loop to that DESC corresponds. | |
793 | ||
17684618 ZD |
794 | If N is number of iterations of the loop and MAY_BE_ZERO is the condition |
795 | under that loop exits in the first iteration even if N != 0, | |
796 | ||
797 | while (1) | |
798 | { | |
799 | x = phi (init, next); | |
800 | ||
801 | pre; | |
802 | if (st) | |
803 | break; | |
804 | post; | |
805 | } | |
806 | ||
807 | becomes (with possibly the exit conditions formulated a bit differently, | |
808 | avoiding the need to create a new iv): | |
809 | ||
810 | if (MAY_BE_ZERO || N < FACTOR) | |
811 | goto rest; | |
812 | ||
813 | do | |
814 | { | |
815 | x = phi (init, next); | |
816 | ||
817 | pre; | |
818 | post; | |
819 | pre; | |
820 | post; | |
821 | ... | |
822 | pre; | |
823 | post; | |
824 | N -= FACTOR; | |
825 | ||
826 | } while (N >= FACTOR); | |
827 | ||
828 | rest: | |
829 | init' = phi (init, x); | |
830 | ||
831 | while (1) | |
832 | { | |
833 | x = phi (init', next); | |
834 | ||
835 | pre; | |
836 | if (st) | |
837 | break; | |
838 | post; | |
567b96ed ZD |
839 | } |
840 | ||
841 | Before the loop is unrolled, TRANSFORM is called for it (only for the | |
842 | unrolled loop, but not for its versioned copy). DATA is passed to | |
843 | TRANSFORM. */ | |
17684618 | 844 | |
03cb2019 ZD |
845 | /* Probability in % that the unrolled loop is entered. Just a guess. */ |
846 | #define PROB_UNROLLED_LOOP_ENTERED 90 | |
847 | ||
17684618 | 848 | void |
567b96ed ZD |
849 | tree_transform_and_unroll_loop (struct loop *loop, unsigned factor, |
850 | edge exit, struct tree_niter_desc *desc, | |
851 | transform_callback transform, | |
852 | void *data) | |
17684618 | 853 | { |
14fa2cc0 | 854 | tree exit_if, ctr_before, ctr_after; |
17684618 ZD |
855 | tree enter_main_cond, exit_base, exit_step, exit_bound; |
856 | enum tree_code exit_cmp; | |
857 | tree phi_old_loop, phi_new_loop, phi_rest, init, next, new_init, var; | |
858 | struct loop *new_loop; | |
859 | basic_block rest, exit_bb; | |
860 | edge old_entry, new_entry, old_latch, precond_edge, new_exit; | |
14fa2cc0 | 861 | edge new_nonexit, e; |
17684618 ZD |
862 | block_stmt_iterator bsi; |
863 | use_operand_p op; | |
864 | bool ok; | |
03cb2019 | 865 | unsigned est_niter, prob_entry, scale_unrolled, scale_rest, freq_e, freq_h; |
14fa2cc0 | 866 | unsigned new_est_niter, i, prob; |
8e08deeb | 867 | unsigned irr = loop_preheader_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP; |
17684618 | 868 | sbitmap wont_exit; |
14fa2cc0 | 869 | VEC (edge, heap) *to_remove = NULL; |
17684618 ZD |
870 | |
871 | est_niter = expected_loop_iterations (loop); | |
872 | determine_exit_conditions (loop, desc, factor, | |
873 | &enter_main_cond, &exit_base, &exit_step, | |
874 | &exit_cmp, &exit_bound); | |
875 | ||
03cb2019 ZD |
876 | /* Let us assume that the unrolled loop is quite likely to be entered. */ |
877 | if (integer_nonzerop (enter_main_cond)) | |
878 | prob_entry = REG_BR_PROB_BASE; | |
879 | else | |
880 | prob_entry = PROB_UNROLLED_LOOP_ENTERED * REG_BR_PROB_BASE / 100; | |
881 | ||
882 | /* The values for scales should keep profile consistent, and somewhat close | |
883 | to correct. | |
884 | ||
885 | TODO: The current value of SCALE_REST makes it appear that the loop that | |
886 | is created by splitting the remaining iterations of the unrolled loop is | |
887 | executed the same number of times as the original loop, and with the same | |
888 | frequencies, which is obviously wrong. This does not appear to cause | |
889 | problems, so we do not bother with fixing it for now. To make the profile | |
890 | correct, we would need to change the probability of the exit edge of the | |
891 | loop, and recompute the distribution of frequencies in its body because | |
892 | of this change (scale the frequencies of blocks before and after the exit | |
893 | by appropriate factors). */ | |
894 | scale_unrolled = prob_entry; | |
895 | scale_rest = REG_BR_PROB_BASE; | |
896 | ||
897 | new_loop = loop_version (loop, enter_main_cond, NULL, | |
898 | prob_entry, scale_unrolled, scale_rest, true); | |
17684618 ZD |
899 | gcc_assert (new_loop != NULL); |
900 | update_ssa (TODO_update_ssa); | |
901 | ||
567b96ed | 902 | /* Determine the probability of the exit edge of the unrolled loop. */ |
03cb2019 ZD |
903 | new_est_niter = est_niter / factor; |
904 | ||
905 | /* Without profile feedback, loops for that we do not know a better estimate | |
906 | are assumed to roll 10 times. When we unroll such loop, it appears to | |
907 | roll too little, and it may even seem to be cold. To avoid this, we | |
908 | ensure that the created loop appears to roll at least 5 times (but at | |
909 | most as many times as before unrolling). */ | |
910 | if (new_est_niter < 5) | |
911 | { | |
912 | if (est_niter < 5) | |
913 | new_est_niter = est_niter; | |
914 | else | |
915 | new_est_niter = 5; | |
916 | } | |
917 | ||
14fa2cc0 ZD |
918 | /* Prepare the cfg and update the phi nodes. Move the loop exit to the |
919 | loop latch (and make its condition dummy, for the moment). */ | |
17684618 ZD |
920 | rest = loop_preheader_edge (new_loop)->src; |
921 | precond_edge = single_pred_edge (rest); | |
598ec7bd | 922 | split_edge (loop_latch_edge (loop)); |
17684618 ZD |
923 | exit_bb = single_pred (loop->latch); |
924 | ||
14fa2cc0 ZD |
925 | /* Since the exit edge will be removed, the frequency of all the blocks |
926 | in the loop that are dominated by it must be scaled by | |
927 | 1 / (1 - exit->probability). */ | |
928 | scale_dominated_blocks_in_loop (loop, exit->src, | |
929 | REG_BR_PROB_BASE, | |
930 | REG_BR_PROB_BASE - exit->probability); | |
931 | ||
567b96ed | 932 | bsi = bsi_last (exit_bb); |
a9b77cd1 ZD |
933 | exit_if = build3 (COND_EXPR, void_type_node, boolean_true_node, |
934 | NULL_TREE, NULL_TREE); | |
935 | ||
567b96ed | 936 | bsi_insert_after (&bsi, exit_if, BSI_NEW_STMT); |
8e08deeb | 937 | new_exit = make_edge (exit_bb, rest, EDGE_FALSE_VALUE | irr); |
6270df4c | 938 | rescan_loop_exit (new_exit, true, false); |
14fa2cc0 ZD |
939 | |
940 | /* Set the probability of new exit to the same of the old one. Fix | |
941 | the frequency of the latch block, by scaling it back by | |
942 | 1 - exit->probability. */ | |
943 | new_exit->count = exit->count; | |
944 | new_exit->probability = exit->probability; | |
17684618 | 945 | new_nonexit = single_pred_edge (loop->latch); |
14fa2cc0 | 946 | new_nonexit->probability = REG_BR_PROB_BASE - exit->probability; |
17684618 | 947 | new_nonexit->flags = EDGE_TRUE_VALUE; |
14fa2cc0 ZD |
948 | new_nonexit->count -= exit->count; |
949 | if (new_nonexit->count < 0) | |
950 | new_nonexit->count = 0; | |
951 | scale_bbs_frequencies_int (&loop->latch, 1, new_nonexit->probability, | |
952 | REG_BR_PROB_BASE); | |
17684618 ZD |
953 | |
954 | old_entry = loop_preheader_edge (loop); | |
955 | new_entry = loop_preheader_edge (new_loop); | |
956 | old_latch = loop_latch_edge (loop); | |
957 | for (phi_old_loop = phi_nodes (loop->header), | |
958 | phi_new_loop = phi_nodes (new_loop->header); | |
959 | phi_old_loop; | |
960 | phi_old_loop = PHI_CHAIN (phi_old_loop), | |
961 | phi_new_loop = PHI_CHAIN (phi_new_loop)) | |
962 | { | |
963 | init = PHI_ARG_DEF_FROM_EDGE (phi_old_loop, old_entry); | |
964 | op = PHI_ARG_DEF_PTR_FROM_EDGE (phi_new_loop, new_entry); | |
965 | gcc_assert (operand_equal_for_phi_arg_p (init, USE_FROM_PTR (op))); | |
966 | next = PHI_ARG_DEF_FROM_EDGE (phi_old_loop, old_latch); | |
967 | ||
968 | /* Prefer using original variable as a base for the new ssa name. | |
969 | This is necessary for virtual ops, and useful in order to avoid | |
970 | losing debug info for real ops. */ | |
971 | if (TREE_CODE (next) == SSA_NAME) | |
972 | var = SSA_NAME_VAR (next); | |
973 | else if (TREE_CODE (init) == SSA_NAME) | |
974 | var = SSA_NAME_VAR (init); | |
975 | else | |
976 | { | |
977 | var = create_tmp_var (TREE_TYPE (init), "unrinittmp"); | |
f004ab02 | 978 | add_referenced_var (var); |
17684618 ZD |
979 | } |
980 | ||
981 | new_init = make_ssa_name (var, NULL_TREE); | |
982 | phi_rest = create_phi_node (new_init, rest); | |
983 | SSA_NAME_DEF_STMT (new_init) = phi_rest; | |
984 | ||
985 | add_phi_arg (phi_rest, init, precond_edge); | |
986 | add_phi_arg (phi_rest, next, new_exit); | |
987 | SET_USE (op, new_init); | |
988 | } | |
989 | ||
14fa2cc0 ZD |
990 | remove_path (exit); |
991 | ||
567b96ed ZD |
992 | /* Transform the loop. */ |
993 | if (transform) | |
994 | (*transform) (loop, data); | |
995 | ||
14fa2cc0 ZD |
996 | /* Unroll the loop and remove the exits in all iterations except for the |
997 | last one. */ | |
567b96ed ZD |
998 | wont_exit = sbitmap_alloc (factor); |
999 | sbitmap_ones (wont_exit); | |
14fa2cc0 ZD |
1000 | RESET_BIT (wont_exit, factor - 1); |
1001 | ||
567b96ed ZD |
1002 | ok = tree_duplicate_loop_to_header_edge |
1003 | (loop, loop_latch_edge (loop), factor - 1, | |
14fa2cc0 | 1004 | wont_exit, new_exit, &to_remove, DLTHE_FLAG_UPDATE_FREQ); |
567b96ed ZD |
1005 | free (wont_exit); |
1006 | gcc_assert (ok); | |
14fa2cc0 ZD |
1007 | |
1008 | for (i = 0; VEC_iterate (edge, to_remove, i, e); i++) | |
1009 | { | |
1010 | ok = remove_path (e); | |
1011 | gcc_assert (ok); | |
1012 | } | |
1013 | VEC_free (edge, heap, to_remove); | |
567b96ed ZD |
1014 | update_ssa (TODO_update_ssa); |
1015 | ||
1016 | /* Ensure that the frequencies in the loop match the new estimated | |
1017 | number of iterations, and change the probability of the new | |
1018 | exit edge. */ | |
1019 | freq_h = loop->header->frequency; | |
1020 | freq_e = EDGE_FREQUENCY (loop_preheader_edge (loop)); | |
1021 | if (freq_h != 0) | |
1022 | scale_loop_frequencies (loop, freq_e * (new_est_niter + 1), freq_h); | |
1023 | ||
1024 | exit_bb = single_pred (loop->latch); | |
1025 | new_exit = find_edge (exit_bb, rest); | |
1026 | new_exit->count = loop_preheader_edge (loop)->count; | |
1027 | new_exit->probability = REG_BR_PROB_BASE / (new_est_niter + 1); | |
1028 | ||
1029 | rest->count += new_exit->count; | |
1030 | rest->frequency += EDGE_FREQUENCY (new_exit); | |
1031 | ||
1032 | new_nonexit = single_pred_edge (loop->latch); | |
14fa2cc0 | 1033 | prob = new_nonexit->probability; |
567b96ed | 1034 | new_nonexit->probability = REG_BR_PROB_BASE - new_exit->probability; |
14fa2cc0 ZD |
1035 | new_nonexit->count = exit_bb->count - new_exit->count; |
1036 | if (new_nonexit->count < 0) | |
1037 | new_nonexit->count = 0; | |
567b96ed | 1038 | scale_bbs_frequencies_int (&loop->latch, 1, new_nonexit->probability, |
14fa2cc0 | 1039 | prob); |
567b96ed | 1040 | |
17684618 ZD |
1041 | /* Finally create the new counter for number of iterations and add the new |
1042 | exit instruction. */ | |
1043 | bsi = bsi_last (exit_bb); | |
567b96ed | 1044 | exit_if = bsi_stmt (bsi); |
17684618 | 1045 | create_iv (exit_base, exit_step, NULL_TREE, loop, |
567b96ed ZD |
1046 | &bsi, false, &ctr_before, &ctr_after); |
1047 | COND_EXPR_COND (exit_if) = build2 (exit_cmp, boolean_type_node, ctr_after, | |
1048 | exit_bound); | |
1049 | update_stmt (exit_if); | |
17684618 | 1050 | |
c0493b13 | 1051 | #ifdef ENABLE_CHECKING |
17684618 ZD |
1052 | verify_flow_info (); |
1053 | verify_dominators (CDI_DOMINATORS); | |
d73be268 | 1054 | verify_loop_structure (); |
17684618 | 1055 | verify_loop_closed_ssa (); |
c0493b13 | 1056 | #endif |
17684618 | 1057 | } |
567b96ed ZD |
1058 | |
1059 | /* Wrapper over tree_transform_and_unroll_loop for case we do not | |
1060 | want to transform the loop before unrolling. The meaning | |
1061 | of the arguments is the same as for tree_transform_and_unroll_loop. */ | |
1062 | ||
1063 | void | |
1064 | tree_unroll_loop (struct loop *loop, unsigned factor, | |
1065 | edge exit, struct tree_niter_desc *desc) | |
1066 | { | |
1067 | tree_transform_and_unroll_loop (loop, factor, exit, desc, | |
1068 | NULL, NULL); | |
1069 | } |