1 /* 2 * Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "opto/loopnode.hpp" 27 #include "opto/addnode.hpp" 28 #include "opto/callnode.hpp" 29 #include "opto/connode.hpp" 30 #include "opto/convertnode.hpp" 31 #include "opto/loopnode.hpp" 32 #include "opto/matcher.hpp" 33 #include "opto/mulnode.hpp" 34 #include "opto/opaquenode.hpp" 35 #include "opto/rootnode.hpp" 36 #include "opto/subnode.hpp" 37 #include <fenv.h> 38 #include <math.h> 39 40 /* 41 * The general idea of Loop Predication is to insert a predicate on the entry 42 * path to a loop, and raise a uncommon trap if the check of the condition fails. 43 * The condition checks are promoted from inside the loop body, and thus 44 * the checks inside the loop could be eliminated. Currently, loop predication 45 * optimization has been applied to remove array range check and loop invariant 46 * checks (such as null checks). 47 */ 48 49 //-------------------------------register_control------------------------- 50 void PhaseIdealLoop::register_control(Node* n, IdealLoopTree *loop, Node* pred) { 51 assert(n->is_CFG(), "must be control node"); 52 _igvn.register_new_node_with_optimizer(n); 53 loop->_body.push(n); 54 set_loop(n, loop); 55 // When called from beautify_loops() idom is not constructed yet. 56 if (_idom != NULL) { 57 set_idom(n, pred, dom_depth(pred)); 58 } 59 } 60 61 //------------------------------create_new_if_for_predicate------------------------ 62 // create a new if above the uct_if_pattern for the predicate to be promoted. 63 // 64 // before after 65 // ---------- ---------- 66 // ctrl ctrl 67 // | | 68 // | | 69 // v v 70 // iff new_iff 71 // / \ / \ 72 // / \ / \ 73 // v v v v 74 // uncommon_proj cont_proj if_uct if_cont 75 // \ | | | | 76 // \ | | | | 77 // v v v | v 78 // rgn loop | iff 79 // | | / \ 80 // | | / \ 81 // v | v v 82 // uncommon_trap | uncommon_proj cont_proj 83 // \ \ | | 84 // \ \ | | 85 // v v v v 86 // rgn loop 87 // | 88 // | 89 // v 90 // uncommon_trap 91 // 92 // 93 // We will create a region to guard the uct call if there is no one there. 94 // The true projection (if_cont) of the new_iff is returned. 95 // This code is also used to clone predicates to cloned loops. 96 ProjNode* PhaseIdealLoop::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, 97 Deoptimization::DeoptReason reason, 98 int opcode) { 99 assert(cont_proj->is_uncommon_trap_if_pattern(reason), "must be a uct if pattern!"); 100 IfNode* iff = cont_proj->in(0)->as_If(); 101 102 ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); 103 Node *rgn = uncommon_proj->unique_ctrl_out(); 104 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); 105 106 uint proj_index = 1; // region's edge corresponding to uncommon_proj 107 if (!rgn->is_Region()) { // create a region to guard the call 108 assert(rgn->is_Call(), "must be call uct"); 109 CallNode* call = rgn->as_Call(); 110 IdealLoopTree* loop = get_loop(call); 111 rgn = new RegionNode(1); 112 rgn->add_req(uncommon_proj); 113 register_control(rgn, loop, uncommon_proj); 114 _igvn.replace_input_of(call, 0, rgn); 115 // When called from beautify_loops() idom is not constructed yet. 116 if (_idom != NULL) { 117 set_idom(call, rgn, dom_depth(rgn)); 118 } 119 for (DUIterator_Fast imax, i = uncommon_proj->fast_outs(imax); i < imax; i++) { 120 Node* n = uncommon_proj->fast_out(i); 121 if (n->is_Load() || n->is_Store()) { 122 _igvn.replace_input_of(n, 0, rgn); 123 --i; --imax; 124 } 125 } 126 } else { 127 // Find region's edge corresponding to uncommon_proj 128 for (; proj_index < rgn->req(); proj_index++) 129 if (rgn->in(proj_index) == uncommon_proj) break; 130 assert(proj_index < rgn->req(), "sanity"); 131 } 132 133 Node* entry = iff->in(0); 134 if (new_entry != NULL) { 135 // Clonning the predicate to new location. 136 entry = new_entry; 137 } 138 // Create new_iff 139 IdealLoopTree* lp = get_loop(entry); 140 IfNode* new_iff = NULL; 141 if (opcode == Op_If) { 142 new_iff = new IfNode(entry, iff->in(1), iff->_prob, iff->_fcnt); 143 } else { 144 assert(opcode == Op_RangeCheck, "no other if variant here"); 145 new_iff = new RangeCheckNode(entry, iff->in(1), iff->_prob, iff->_fcnt); 146 } 147 register_control(new_iff, lp, entry); 148 Node *if_cont = new IfTrueNode(new_iff); 149 Node *if_uct = new IfFalseNode(new_iff); 150 if (cont_proj->is_IfFalse()) { 151 // Swap 152 Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; 153 } 154 register_control(if_cont, lp, new_iff); 155 register_control(if_uct, get_loop(rgn), new_iff); 156 157 // if_uct to rgn 158 _igvn.hash_delete(rgn); 159 rgn->add_req(if_uct); 160 // When called from beautify_loops() idom is not constructed yet. 161 if (_idom != NULL) { 162 Node* ridom = idom(rgn); 163 Node* nrdom = dom_lca(ridom, new_iff); 164 set_idom(rgn, nrdom, dom_depth(rgn)); 165 } 166 167 // If rgn has phis add new edges which has the same 168 // value as on original uncommon_proj pass. 169 assert(rgn->in(rgn->req() -1) == if_uct, "new edge should be last"); 170 bool has_phi = false; 171 for (DUIterator_Fast imax, i = rgn->fast_outs(imax); i < imax; i++) { 172 Node* use = rgn->fast_out(i); 173 if (use->is_Phi() && use->outcnt() > 0) { 174 assert(use->in(0) == rgn, ""); 175 _igvn.rehash_node_delayed(use); 176 use->add_req(use->in(proj_index)); 177 has_phi = true; 178 } 179 } 180 assert(!has_phi || rgn->req() > 3, "no phis when region is created"); 181 182 if (new_entry == NULL) { 183 // Attach if_cont to iff 184 _igvn.replace_input_of(iff, 0, if_cont); 185 if (_idom != NULL) { 186 set_idom(iff, if_cont, dom_depth(iff)); 187 } 188 } 189 return if_cont->as_Proj(); 190 } 191 192 //------------------------------create_new_if_for_predicate------------------------ 193 // Create a new if below new_entry for the predicate to be cloned (IGVN optimization) 194 ProjNode* PhaseIterGVN::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, 195 Deoptimization::DeoptReason reason, 196 int opcode) { 197 assert(new_entry != 0, "only used for clone predicate"); 198 assert(cont_proj->is_uncommon_trap_if_pattern(reason), "must be a uct if pattern!"); 199 IfNode* iff = cont_proj->in(0)->as_If(); 200 201 ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); 202 Node *rgn = uncommon_proj->unique_ctrl_out(); 203 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); 204 205 uint proj_index = 1; // region's edge corresponding to uncommon_proj 206 if (!rgn->is_Region()) { // create a region to guard the call 207 assert(rgn->is_Call(), "must be call uct"); 208 CallNode* call = rgn->as_Call(); 209 rgn = new RegionNode(1); 210 register_new_node_with_optimizer(rgn); 211 rgn->add_req(uncommon_proj); 212 replace_input_of(call, 0, rgn); 213 } else { 214 // Find region's edge corresponding to uncommon_proj 215 for (; proj_index < rgn->req(); proj_index++) 216 if (rgn->in(proj_index) == uncommon_proj) break; 217 assert(proj_index < rgn->req(), "sanity"); 218 } 219 220 // Create new_iff in new location. 221 IfNode* new_iff = NULL; 222 if (opcode == Op_If) { 223 new_iff = new IfNode(new_entry, iff->in(1), iff->_prob, iff->_fcnt); 224 } else { 225 assert(opcode == Op_RangeCheck, "no other if variant here"); 226 new_iff = new RangeCheckNode(new_entry, iff->in(1), iff->_prob, iff->_fcnt); 227 } 228 229 register_new_node_with_optimizer(new_iff); 230 Node *if_cont = new IfTrueNode(new_iff); 231 Node *if_uct = new IfFalseNode(new_iff); 232 if (cont_proj->is_IfFalse()) { 233 // Swap 234 Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; 235 } 236 register_new_node_with_optimizer(if_cont); 237 register_new_node_with_optimizer(if_uct); 238 239 // if_uct to rgn 240 hash_delete(rgn); 241 rgn->add_req(if_uct); 242 243 // If rgn has phis add corresponding new edges which has the same 244 // value as on original uncommon_proj pass. 245 assert(rgn->in(rgn->req() -1) == if_uct, "new edge should be last"); 246 bool has_phi = false; 247 for (DUIterator_Fast imax, i = rgn->fast_outs(imax); i < imax; i++) { 248 Node* use = rgn->fast_out(i); 249 if (use->is_Phi() && use->outcnt() > 0) { 250 rehash_node_delayed(use); 251 use->add_req(use->in(proj_index)); 252 has_phi = true; 253 } 254 } 255 assert(!has_phi || rgn->req() > 3, "no phis when region is created"); 256 257 return if_cont->as_Proj(); 258 } 259 260 //--------------------------clone_predicate----------------------- 261 ProjNode* PhaseIdealLoop::clone_predicate(ProjNode* predicate_proj, Node* new_entry, 262 Deoptimization::DeoptReason reason, 263 PhaseIdealLoop* loop_phase, 264 PhaseIterGVN* igvn) { 265 ProjNode* new_predicate_proj; 266 if (loop_phase != NULL) { 267 new_predicate_proj = loop_phase->create_new_if_for_predicate(predicate_proj, new_entry, reason, Op_If); 268 } else { 269 new_predicate_proj = igvn->create_new_if_for_predicate(predicate_proj, new_entry, reason, Op_If); 270 } 271 IfNode* iff = new_predicate_proj->in(0)->as_If(); 272 Node* ctrl = iff->in(0); 273 274 // Match original condition since predicate's projections could be swapped. 275 assert(predicate_proj->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be"); 276 Node* opq = new Opaque1Node(igvn->C, predicate_proj->in(0)->in(1)->in(1)->in(1)); 277 igvn->C->add_predicate_opaq(opq); 278 279 Node* bol = new Conv2BNode(opq); 280 if (loop_phase != NULL) { 281 loop_phase->register_new_node(opq, ctrl); 282 loop_phase->register_new_node(bol, ctrl); 283 } else { 284 igvn->register_new_node_with_optimizer(opq); 285 igvn->register_new_node_with_optimizer(bol); 286 } 287 igvn->hash_delete(iff); 288 iff->set_req(1, bol); 289 return new_predicate_proj; 290 } 291 292 293 //--------------------------clone_loop_predicates----------------------- 294 // Interface from IGVN 295 Node* PhaseIterGVN::clone_loop_predicates(Node* old_entry, Node* new_entry, bool clone_limit_check) { 296 return PhaseIdealLoop::clone_loop_predicates(old_entry, new_entry, clone_limit_check, NULL, this); 297 } 298 299 // Interface from PhaseIdealLoop 300 Node* PhaseIdealLoop::clone_loop_predicates(Node* old_entry, Node* new_entry, bool clone_limit_check) { 301 return clone_loop_predicates(old_entry, new_entry, clone_limit_check, this, &this->_igvn); 302 } 303 304 void PhaseIdealLoop::clone_loop_predicates_fix_mem(ProjNode* dom_proj , ProjNode* proj, 305 PhaseIdealLoop* loop_phase, 306 PhaseIterGVN* igvn) { 307 Compile* C = NULL; 308 if (loop_phase != NULL) { 309 igvn = &loop_phase->igvn(); 310 } 311 C = igvn->C; 312 ProjNode* other_dom_proj = dom_proj->in(0)->as_Multi()->proj_out(1-dom_proj->_con); 313 Node* dom_r = other_dom_proj->unique_ctrl_out(); 314 if (dom_r->is_Region()) { 315 assert(dom_r->unique_ctrl_out()->is_Call(), "unc expected"); 316 ProjNode* other_proj = proj->in(0)->as_Multi()->proj_out(1-proj->_con); 317 Node* r = other_proj->unique_ctrl_out(); 318 assert(r->is_Region() && r->unique_ctrl_out()->is_Call(), "cloned predicate should have caused region to be added"); 319 for (DUIterator_Fast imax, i = dom_r->fast_outs(imax); i < imax; i++) { 320 Node* dom_use = dom_r->fast_out(i); 321 if (dom_use->is_Phi() && dom_use->bottom_type() == Type::MEMORY) { 322 assert(dom_use->in(0) == dom_r, ""); 323 Node* phi = NULL; 324 for (DUIterator_Fast jmax, j = r->fast_outs(jmax); j < jmax; j++) { 325 Node* use = r->fast_out(j); 326 if (use->is_Phi() && use->bottom_type() == Type::MEMORY && 327 use->adr_type() == dom_use->adr_type()) { 328 assert(use->in(0) == r, ""); 329 assert(phi == NULL, "only one phi"); 330 phi = use; 331 } 332 } 333 if (phi == NULL) { 334 const TypePtr* adr_type = dom_use->adr_type(); 335 int alias = C->get_alias_index(adr_type); 336 Node* call = r->unique_ctrl_out(); 337 Node* mem = call->in(TypeFunc::Memory); 338 MergeMemNode* mm = NULL; 339 if (mem->is_MergeMem()) { 340 mm = mem->clone()->as_MergeMem(); 341 if (adr_type == TypePtr::BOTTOM) { 342 mem = mem->as_MergeMem()->base_memory(); 343 } else { 344 mem = mem->as_MergeMem()->memory_at(alias); 345 } 346 } else { 347 mm = MergeMemNode::make(mem); 348 } 349 phi = PhiNode::make(r, mem, Type::MEMORY, adr_type); 350 if (adr_type == TypePtr::BOTTOM) { 351 mm->set_base_memory(phi); 352 } else { 353 mm->set_memory_at(alias, phi); 354 } 355 if (loop_phase != NULL) { 356 loop_phase->register_new_node(mm, r); 357 loop_phase->register_new_node(phi, r); 358 } else { 359 igvn->register_new_node_with_optimizer(mm); 360 igvn->register_new_node_with_optimizer(phi); 361 } 362 igvn->replace_input_of(call, TypeFunc::Memory, mm); 363 } 364 igvn->replace_input_of(phi, r->find_edge(other_proj), dom_use->in(dom_r->find_edge(other_dom_proj))); 365 } 366 } 367 } 368 } 369 370 371 // Clone loop predicates to cloned loops (peeled, unswitched, split_if). 372 Node* PhaseIdealLoop::clone_loop_predicates(Node* old_entry, Node* new_entry, 373 bool clone_limit_check, 374 PhaseIdealLoop* loop_phase, 375 PhaseIterGVN* igvn) { 376 #ifdef ASSERT 377 if (new_entry == NULL || !(new_entry->is_Proj() || new_entry->is_Region() || new_entry->is_SafePoint())) { 378 if (new_entry != NULL) 379 new_entry->dump(); 380 assert(false, "not IfTrue, IfFalse, Region or SafePoint"); 381 } 382 #endif 383 // Search original predicates 384 Node* entry = old_entry; 385 ProjNode* limit_check_proj = NULL; 386 limit_check_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); 387 if (limit_check_proj != NULL) { 388 entry = skip_loop_predicates(entry); 389 } 390 ProjNode* profile_predicate_proj = NULL; 391 ProjNode* predicate_proj = NULL; 392 if (UseProfiledLoopPredicate) { 393 profile_predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_profile_predicate); 394 if (profile_predicate_proj != NULL) { 395 entry = skip_loop_predicates(entry); 396 } 397 } 398 if (UseLoopPredicate) { 399 predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); 400 } 401 if (predicate_proj != NULL) { // right pattern that can be used by loop predication 402 // clone predicate 403 ProjNode* proj = clone_predicate(predicate_proj, new_entry, 404 Deoptimization::Reason_predicate, 405 loop_phase, igvn); 406 assert(proj != NULL, "IfTrue or IfFalse after clone predicate"); 407 new_entry = proj; 408 if (TraceLoopPredicate) { 409 tty->print("Loop Predicate cloned: "); 410 debug_only( new_entry->in(0)->dump(); ); 411 } 412 if (profile_predicate_proj != NULL) { 413 // A node that produces memory may be out of loop and depend on 414 // a profiled predicates. In that case the memory state at the 415 // end of profiled predicates and at the end of predicates are 416 // not the same. The cloned predicates are dominated by the 417 // profiled predicates but may have the wrong memory 418 // state. Update it. 419 clone_loop_predicates_fix_mem(profile_predicate_proj, proj, loop_phase, igvn); 420 } 421 } 422 if (profile_predicate_proj != NULL) { // right pattern that can be used by loop predication 423 // clone predicate 424 new_entry = clone_predicate(profile_predicate_proj, new_entry, 425 Deoptimization::Reason_profile_predicate, 426 loop_phase, igvn); 427 assert(new_entry != NULL && new_entry->is_Proj(), "IfTrue or IfFalse after clone predicate"); 428 if (TraceLoopPredicate) { 429 tty->print("Loop Predicate cloned: "); 430 debug_only( new_entry->in(0)->dump(); ); 431 } 432 } 433 if (limit_check_proj != NULL && clone_limit_check) { 434 // Clone loop limit check last to insert it before loop. 435 // Don't clone a limit check which was already finalized 436 // for this counted loop (only one limit check is needed). 437 new_entry = clone_predicate(limit_check_proj, new_entry, 438 Deoptimization::Reason_loop_limit_check, 439 loop_phase, igvn); 440 assert(new_entry != NULL && new_entry->is_Proj(), "IfTrue or IfFalse after clone limit check"); 441 if (TraceLoopLimitCheck) { 442 tty->print("Loop Limit Check cloned: "); 443 debug_only( new_entry->in(0)->dump(); ) 444 } 445 } 446 return new_entry; 447 } 448 449 //--------------------------skip_loop_predicates------------------------------ 450 // Skip related predicates. 451 Node* PhaseIdealLoop::skip_loop_predicates(Node* entry) { 452 IfNode* iff = entry->in(0)->as_If(); 453 ProjNode* uncommon_proj = iff->proj_out(1 - entry->as_Proj()->_con); 454 Node* rgn = uncommon_proj->unique_ctrl_out(); 455 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); 456 entry = entry->in(0)->in(0); 457 while (entry != NULL && entry->is_Proj() && entry->in(0)->is_If()) { 458 uncommon_proj = entry->in(0)->as_If()->proj_out(1 - entry->as_Proj()->_con); 459 if (uncommon_proj->unique_ctrl_out() != rgn) 460 break; 461 entry = entry->in(0)->in(0); 462 } 463 return entry; 464 } 465 466 Node* PhaseIdealLoop::skip_all_loop_predicates(Node* entry) { 467 Node* predicate = NULL; 468 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); 469 if (predicate != NULL) { 470 entry = skip_loop_predicates(entry); 471 } 472 if (UseProfiledLoopPredicate) { 473 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_profile_predicate); 474 if (predicate != NULL) { // right pattern that can be used by loop predication 475 entry = skip_loop_predicates(entry); 476 } 477 } 478 if (UseLoopPredicate) { 479 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); 480 if (predicate != NULL) { // right pattern that can be used by loop predication 481 entry = skip_loop_predicates(entry); 482 } 483 } 484 return entry; 485 } 486 487 //--------------------------find_predicate_insertion_point------------------- 488 // Find a good location to insert a predicate 489 ProjNode* PhaseIdealLoop::find_predicate_insertion_point(Node* start_c, Deoptimization::DeoptReason reason) { 490 if (start_c == NULL || !start_c->is_Proj()) 491 return NULL; 492 if (start_c->as_Proj()->is_uncommon_trap_if_pattern(reason)) { 493 return start_c->as_Proj(); 494 } 495 return NULL; 496 } 497 498 //--------------------------find_predicate------------------------------------ 499 // Find a predicate 500 Node* PhaseIdealLoop::find_predicate(Node* entry) { 501 Node* predicate = NULL; 502 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); 503 if (predicate != NULL) { // right pattern that can be used by loop predication 504 return entry; 505 } 506 if (UseLoopPredicate) { 507 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); 508 if (predicate != NULL) { // right pattern that can be used by loop predication 509 return entry; 510 } 511 } 512 if (UseProfiledLoopPredicate) { 513 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_profile_predicate); 514 if (predicate != NULL) { // right pattern that can be used by loop predication 515 return entry; 516 } 517 } 518 return NULL; 519 } 520 521 //------------------------------Invariance----------------------------------- 522 // Helper class for loop_predication_impl to compute invariance on the fly and 523 // clone invariants. 524 class Invariance : public StackObj { 525 VectorSet _visited, _invariant; 526 Node_Stack _stack; 527 VectorSet _clone_visited; 528 Node_List _old_new; // map of old to new (clone) 529 IdealLoopTree* _lpt; 530 PhaseIdealLoop* _phase; 531 532 // Helper function to set up the invariance for invariance computation 533 // If n is a known invariant, set up directly. Otherwise, look up the 534 // the possibility to push n onto the stack for further processing. 535 void visit(Node* use, Node* n) { 536 if (_lpt->is_invariant(n)) { // known invariant 537 _invariant.set(n->_idx); 538 } else if (!n->is_CFG()) { 539 Node *n_ctrl = _phase->ctrl_or_self(n); 540 Node *u_ctrl = _phase->ctrl_or_self(use); // self if use is a CFG 541 if (_phase->is_dominator(n_ctrl, u_ctrl)) { 542 _stack.push(n, n->in(0) == NULL ? 1 : 0); 543 } 544 } 545 } 546 547 // Compute invariance for "the_node" and (possibly) all its inputs recursively 548 // on the fly 549 void compute_invariance(Node* n) { 550 assert(_visited.test(n->_idx), "must be"); 551 visit(n, n); 552 while (_stack.is_nonempty()) { 553 Node* n = _stack.node(); 554 uint idx = _stack.index(); 555 if (idx == n->req()) { // all inputs are processed 556 _stack.pop(); 557 // n is invariant if it's inputs are all invariant 558 bool all_inputs_invariant = true; 559 for (uint i = 0; i < n->req(); i++) { 560 Node* in = n->in(i); 561 if (in == NULL) continue; 562 assert(_visited.test(in->_idx), "must have visited input"); 563 if (!_invariant.test(in->_idx)) { // bad guy 564 all_inputs_invariant = false; 565 break; 566 } 567 } 568 if (all_inputs_invariant) { 569 // If n's control is a predicate that was moved out of the 570 // loop, it was marked invariant but n is only invariant if 571 // it depends only on that test. Otherwise, unless that test 572 // is out of the loop, it's not invariant. 573 if (n->is_CFG() || n->depends_only_on_test() || n->in(0) == NULL || !_phase->is_member(_lpt, n->in(0))) { 574 _invariant.set(n->_idx); // I am a invariant too 575 } 576 } 577 } else { // process next input 578 _stack.set_index(idx + 1); 579 Node* m = n->in(idx); 580 if (m != NULL && !_visited.test_set(m->_idx)) { 581 visit(n, m); 582 } 583 } 584 } 585 } 586 587 // Helper function to set up _old_new map for clone_nodes. 588 // If n is a known invariant, set up directly ("clone" of n == n). 589 // Otherwise, push n onto the stack for real cloning. 590 void clone_visit(Node* n) { 591 assert(_invariant.test(n->_idx), "must be invariant"); 592 if (_lpt->is_invariant(n)) { // known invariant 593 _old_new.map(n->_idx, n); 594 } else { // to be cloned 595 assert(!n->is_CFG(), "should not see CFG here"); 596 _stack.push(n, n->in(0) == NULL ? 1 : 0); 597 } 598 } 599 600 // Clone "n" and (possibly) all its inputs recursively 601 void clone_nodes(Node* n, Node* ctrl) { 602 clone_visit(n); 603 while (_stack.is_nonempty()) { 604 Node* n = _stack.node(); 605 uint idx = _stack.index(); 606 if (idx == n->req()) { // all inputs processed, clone n! 607 _stack.pop(); 608 // clone invariant node 609 Node* n_cl = n->clone(); 610 _old_new.map(n->_idx, n_cl); 611 _phase->register_new_node(n_cl, ctrl); 612 for (uint i = 0; i < n->req(); i++) { 613 Node* in = n_cl->in(i); 614 if (in == NULL) continue; 615 n_cl->set_req(i, _old_new[in->_idx]); 616 } 617 } else { // process next input 618 _stack.set_index(idx + 1); 619 Node* m = n->in(idx); 620 if (m != NULL && !_clone_visited.test_set(m->_idx)) { 621 clone_visit(m); // visit the input 622 } 623 } 624 } 625 } 626 627 public: 628 Invariance(Arena* area, IdealLoopTree* lpt) : 629 _visited(area), _invariant(area), 630 _stack(area, 10 /* guess */), 631 _clone_visited(area), _old_new(area), 632 _lpt(lpt), _phase(lpt->_phase) 633 { 634 LoopNode* head = _lpt->_head->as_Loop(); 635 Node* entry = head->skip_strip_mined()->in(LoopNode::EntryControl); 636 if (entry->outcnt() != 1) { 637 // If a node is pinned between the predicates and the loop 638 // entry, we won't be able to move any node in the loop that 639 // depends on it above it in a predicate. Mark all those nodes 640 // as non loop invariatnt. 641 Unique_Node_List wq; 642 wq.push(entry); 643 for (uint next = 0; next < wq.size(); ++next) { 644 Node *n = wq.at(next); 645 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 646 Node* u = n->fast_out(i); 647 if (!u->is_CFG()) { 648 Node* c = _phase->get_ctrl(u); 649 if (_lpt->is_member(_phase->get_loop(c)) || _phase->is_dominator(c, head)) { 650 _visited.set(u->_idx); 651 wq.push(u); 652 } 653 } 654 } 655 } 656 } 657 } 658 659 // Map old to n for invariance computation and clone 660 void map_ctrl(Node* old, Node* n) { 661 assert(old->is_CFG() && n->is_CFG(), "must be"); 662 _old_new.map(old->_idx, n); // "clone" of old is n 663 _invariant.set(old->_idx); // old is invariant 664 _clone_visited.set(old->_idx); 665 } 666 667 // Driver function to compute invariance 668 bool is_invariant(Node* n) { 669 if (!_visited.test_set(n->_idx)) 670 compute_invariance(n); 671 return (_invariant.test(n->_idx) != 0); 672 } 673 674 // Driver function to clone invariant 675 Node* clone(Node* n, Node* ctrl) { 676 assert(ctrl->is_CFG(), "must be"); 677 assert(_invariant.test(n->_idx), "must be an invariant"); 678 if (!_clone_visited.test(n->_idx)) 679 clone_nodes(n, ctrl); 680 return _old_new[n->_idx]; 681 } 682 }; 683 684 //------------------------------is_range_check_if ----------------------------------- 685 // Returns true if the predicate of iff is in "scale*iv + offset u< load_range(ptr)" format 686 // Note: this function is particularly designed for loop predication. We require load_range 687 // and offset to be loop invariant computed on the fly by "invar" 688 bool IdealLoopTree::is_range_check_if(IfNode *iff, PhaseIdealLoop *phase, Invariance& invar) const { 689 if (!is_loop_exit(iff)) { 690 return false; 691 } 692 if (!iff->in(1)->is_Bool()) { 693 return false; 694 } 695 const BoolNode *bol = iff->in(1)->as_Bool(); 696 if (bol->_test._test != BoolTest::lt) { 697 return false; 698 } 699 if (!bol->in(1)->is_Cmp()) { 700 return false; 701 } 702 const CmpNode *cmp = bol->in(1)->as_Cmp(); 703 if (cmp->Opcode() != Op_CmpU) { 704 return false; 705 } 706 Node* range = cmp->in(2); 707 if (range->Opcode() != Op_LoadRange && !iff->is_RangeCheck()) { 708 const TypeInt* tint = phase->_igvn.type(range)->isa_int(); 709 if (tint == NULL || tint->empty() || tint->_lo < 0) { 710 // Allow predication on positive values that aren't LoadRanges. 711 // This allows optimization of loops where the length of the 712 // array is a known value and doesn't need to be loaded back 713 // from the array. 714 return false; 715 } 716 } 717 if (!invar.is_invariant(range)) { 718 return false; 719 } 720 Node *iv = _head->as_CountedLoop()->phi(); 721 int scale = 0; 722 Node *offset = NULL; 723 if (!phase->is_scaled_iv_plus_offset(cmp->in(1), iv, &scale, &offset)) { 724 return false; 725 } 726 if (offset && !invar.is_invariant(offset)) { // offset must be invariant 727 return false; 728 } 729 return true; 730 } 731 732 //------------------------------rc_predicate----------------------------------- 733 // Create a range check predicate 734 // 735 // for (i = init; i < limit; i += stride) { 736 // a[scale*i+offset] 737 // } 738 // 739 // Compute max(scale*i + offset) for init <= i < limit and build the predicate 740 // as "max(scale*i + offset) u< a.length". 741 // 742 // There are two cases for max(scale*i + offset): 743 // (1) stride*scale > 0 744 // max(scale*i + offset) = scale*(limit-stride) + offset 745 // (2) stride*scale < 0 746 // max(scale*i + offset) = scale*init + offset 747 BoolNode* PhaseIdealLoop::rc_predicate(IdealLoopTree *loop, Node* ctrl, 748 int scale, Node* offset, 749 Node* init, Node* limit, jint stride, 750 Node* range, bool upper, bool &overflow) { 751 jint con_limit = (limit != NULL && limit->is_Con()) ? limit->get_int() : 0; 752 jint con_init = init->is_Con() ? init->get_int() : 0; 753 jint con_offset = offset->is_Con() ? offset->get_int() : 0; 754 755 stringStream* predString = NULL; 756 if (TraceLoopPredicate) { 757 predString = new stringStream(); 758 predString->print("rc_predicate "); 759 } 760 761 overflow = false; 762 Node* max_idx_expr = NULL; 763 const TypeInt* idx_type = TypeInt::INT; 764 if ((stride > 0) == (scale > 0) == upper) { 765 guarantee(limit != NULL, "sanity"); 766 if (TraceLoopPredicate) { 767 if (limit->is_Con()) { 768 predString->print("(%d ", con_limit); 769 } else { 770 predString->print("(limit "); 771 } 772 predString->print("- %d) ", stride); 773 } 774 // Check if (limit - stride) may overflow 775 const TypeInt* limit_type = _igvn.type(limit)->isa_int(); 776 jint limit_lo = limit_type->_lo; 777 jint limit_hi = limit_type->_hi; 778 if ((stride > 0 && (java_subtract(limit_lo, stride) < limit_lo)) || 779 (stride < 0 && (java_subtract(limit_hi, stride) > limit_hi))) { 780 // No overflow possible 781 ConINode* con_stride = _igvn.intcon(stride); 782 set_ctrl(con_stride, C->root()); 783 max_idx_expr = new SubINode(limit, con_stride); 784 idx_type = TypeInt::make(limit_lo - stride, limit_hi - stride, limit_type->_widen); 785 } else { 786 // May overflow 787 overflow = true; 788 limit = new ConvI2LNode(limit); 789 register_new_node(limit, ctrl); 790 ConLNode* con_stride = _igvn.longcon(stride); 791 set_ctrl(con_stride, C->root()); 792 max_idx_expr = new SubLNode(limit, con_stride); 793 } 794 register_new_node(max_idx_expr, ctrl); 795 } else { 796 if (TraceLoopPredicate) { 797 if (init->is_Con()) { 798 predString->print("%d ", con_init); 799 } else { 800 predString->print("init "); 801 } 802 } 803 idx_type = _igvn.type(init)->isa_int(); 804 max_idx_expr = init; 805 } 806 807 if (scale != 1) { 808 ConNode* con_scale = _igvn.intcon(scale); 809 set_ctrl(con_scale, C->root()); 810 if (TraceLoopPredicate) { 811 predString->print("* %d ", scale); 812 } 813 // Check if (scale * max_idx_expr) may overflow 814 const TypeInt* scale_type = TypeInt::make(scale); 815 MulINode* mul = new MulINode(max_idx_expr, con_scale); 816 idx_type = (TypeInt*)mul->mul_ring(idx_type, scale_type); 817 if (overflow || TypeInt::INT->higher_equal(idx_type)) { 818 // May overflow 819 mul->destruct(); 820 if (!overflow) { 821 max_idx_expr = new ConvI2LNode(max_idx_expr); 822 register_new_node(max_idx_expr, ctrl); 823 } 824 overflow = true; 825 con_scale = _igvn.longcon(scale); 826 set_ctrl(con_scale, C->root()); 827 max_idx_expr = new MulLNode(max_idx_expr, con_scale); 828 } else { 829 // No overflow possible 830 max_idx_expr = mul; 831 } 832 register_new_node(max_idx_expr, ctrl); 833 } 834 835 if (offset && (!offset->is_Con() || con_offset != 0)){ 836 if (TraceLoopPredicate) { 837 if (offset->is_Con()) { 838 predString->print("+ %d ", con_offset); 839 } else { 840 predString->print("+ offset"); 841 } 842 } 843 // Check if (max_idx_expr + offset) may overflow 844 const TypeInt* offset_type = _igvn.type(offset)->isa_int(); 845 jint lo = java_add(idx_type->_lo, offset_type->_lo); 846 jint hi = java_add(idx_type->_hi, offset_type->_hi); 847 if (overflow || (lo > hi) || 848 ((idx_type->_lo & offset_type->_lo) < 0 && lo >= 0) || 849 ((~(idx_type->_hi | offset_type->_hi)) < 0 && hi < 0)) { 850 // May overflow 851 if (!overflow) { 852 max_idx_expr = new ConvI2LNode(max_idx_expr); 853 register_new_node(max_idx_expr, ctrl); 854 } 855 overflow = true; 856 offset = new ConvI2LNode(offset); 857 register_new_node(offset, ctrl); 858 max_idx_expr = new AddLNode(max_idx_expr, offset); 859 } else { 860 // No overflow possible 861 max_idx_expr = new AddINode(max_idx_expr, offset); 862 } 863 register_new_node(max_idx_expr, ctrl); 864 } 865 866 CmpNode* cmp = NULL; 867 if (overflow) { 868 // Integer expressions may overflow, do long comparison 869 range = new ConvI2LNode(range); 870 register_new_node(range, ctrl); 871 cmp = new CmpULNode(max_idx_expr, range); 872 } else { 873 cmp = new CmpUNode(max_idx_expr, range); 874 } 875 register_new_node(cmp, ctrl); 876 BoolNode* bol = new BoolNode(cmp, BoolTest::lt); 877 register_new_node(bol, ctrl); 878 879 if (TraceLoopPredicate) { 880 predString->print_cr("<u range"); 881 tty->print("%s", predString->as_string()); 882 } 883 return bol; 884 } 885 886 // Should loop predication look not only in the path from tail to head 887 // but also in branches of the loop body? 888 bool PhaseIdealLoop::loop_predication_should_follow_branches(IdealLoopTree *loop, ProjNode *predicate_proj, float& loop_trip_cnt) { 889 if (!UseProfiledLoopPredicate) { 890 return false; 891 } 892 893 if (predicate_proj == NULL) { 894 return false; 895 } 896 897 LoopNode* head = loop->_head->as_Loop(); 898 bool follow_branches = true; 899 IdealLoopTree* l = loop->_child; 900 // For leaf loops and loops with a single inner loop 901 while (l != NULL && follow_branches) { 902 IdealLoopTree* child = l; 903 if (child->_child != NULL && 904 child->_head->is_OuterStripMinedLoop()) { 905 assert(child->_child->_next == NULL, "only one inner loop for strip mined loop"); 906 assert(child->_child->_head->is_CountedLoop() && child->_child->_head->as_CountedLoop()->is_strip_mined(), "inner loop should be strip mined"); 907 child = child->_child; 908 } 909 if (child->_child != NULL || child->_irreducible) { 910 follow_branches = false; 911 } 912 l = l->_next; 913 } 914 if (follow_branches) { 915 loop->compute_profile_trip_cnt(this); 916 if (head->is_profile_trip_failed()) { 917 follow_branches = false; 918 } else { 919 loop_trip_cnt = head->profile_trip_cnt(); 920 if (head->is_CountedLoop()) { 921 CountedLoopNode* cl = head->as_CountedLoop(); 922 if (cl->phi() != NULL) { 923 const TypeInt* t = _igvn.type(cl->phi())->is_int(); 924 float worst_case_trip_cnt = ((float)t->_hi - t->_lo) / ABS(cl->stride_con()); 925 if (worst_case_trip_cnt < loop_trip_cnt) { 926 loop_trip_cnt = worst_case_trip_cnt; 927 } 928 } 929 } 930 } 931 } 932 return follow_branches; 933 } 934 935 // Compute probability of reaching some CFG node from a fixed 936 // dominating CFG node 937 class PathFrequency { 938 private: 939 Node* _dom; // frequencies are computed relative to this node 940 Node_Stack _stack; 941 GrowableArray<float> _freqs_stack; // keep track of intermediate result at regions 942 GrowableArray<float> _freqs; // cache frequencies 943 PhaseIdealLoop* _phase; 944 945 void set_rounding(int mode) { 946 // fesetround is broken on windows 947 NOT_WINDOWS(fesetround(mode);) 948 } 949 950 void check_frequency(float f) { 951 NOT_WINDOWS(assert(f <= 1 && f >= 0, "Incorrect frequency");) 952 } 953 954 public: 955 PathFrequency(Node* dom, PhaseIdealLoop* phase) 956 : _dom(dom), _stack(0), _phase(phase) { 957 } 958 959 float to(Node* n) { 960 // post order walk on the CFG graph from n to _dom 961 set_rounding(FE_TOWARDZERO); // make sure rounding doesn't push frequency above 1 962 IdealLoopTree* loop = _phase->get_loop(_dom); 963 Node* c = n; 964 for (;;) { 965 assert(_phase->get_loop(c) == loop, "have to be in the same loop"); 966 if (c == _dom || _freqs.at_grow(c->_idx, -1) >= 0) { 967 float f = c == _dom ? 1 : _freqs.at(c->_idx); 968 Node* prev = c; 969 while (_stack.size() > 0 && prev == c) { 970 Node* n = _stack.node(); 971 if (!n->is_Region()) { 972 if (_phase->get_loop(n) != _phase->get_loop(n->in(0))) { 973 // Found an inner loop: compute frequency of reaching this 974 // exit from the loop head by looking at the number of 975 // times each loop exit was taken 976 IdealLoopTree* inner_loop = _phase->get_loop(n->in(0)); 977 LoopNode* inner_head = inner_loop->_head->as_Loop(); 978 assert(_phase->get_loop(n) == loop, "only 1 inner loop"); 979 if (inner_head->is_OuterStripMinedLoop()) { 980 inner_head->verify_strip_mined(1); 981 if (n->in(0) == inner_head->in(LoopNode::LoopBackControl)->in(0)) { 982 n = n->in(0)->in(0)->in(0); 983 } 984 inner_loop = inner_loop->_child; 985 inner_head = inner_loop->_head->as_Loop(); 986 inner_head->verify_strip_mined(1); 987 } 988 set_rounding(FE_UPWARD); // make sure rounding doesn't push frequency above 1 989 float loop_exit_cnt = 0.0f; 990 for (uint i = 0; i < inner_loop->_body.size(); i++) { 991 Node *n = inner_loop->_body[i]; 992 float c = inner_loop->compute_profile_trip_cnt_helper(n); 993 loop_exit_cnt += c; 994 } 995 set_rounding(FE_TOWARDZERO); 996 float cnt = -1; 997 if (n->in(0)->is_If()) { 998 IfNode* iff = n->in(0)->as_If(); 999 float p = n->in(0)->as_If()->_prob; 1000 if (n->Opcode() == Op_IfFalse) { 1001 p = 1 - p; 1002 } 1003 if (p > PROB_MIN) { 1004 cnt = p * iff->_fcnt; 1005 } else { 1006 cnt = 0; 1007 } 1008 } else { 1009 assert(n->in(0)->is_Jump(), "unsupported node kind"); 1010 JumpNode* jmp = n->in(0)->as_Jump(); 1011 float p = n->in(0)->as_Jump()->_probs[n->as_JumpProj()->_con]; 1012 cnt = p * jmp->_fcnt; 1013 } 1014 float this_exit_f = cnt > 0 ? cnt / loop_exit_cnt : 0; 1015 check_frequency(this_exit_f); 1016 f = f * this_exit_f; 1017 check_frequency(f); 1018 } else { 1019 float p = -1; 1020 if (n->in(0)->is_If()) { 1021 p = n->in(0)->as_If()->_prob; 1022 if (n->Opcode() == Op_IfFalse) { 1023 p = 1 - p; 1024 } 1025 } else { 1026 assert(n->in(0)->is_Jump(), "unsupported node kind"); 1027 p = n->in(0)->as_Jump()->_probs[n->as_JumpProj()->_con]; 1028 } 1029 f = f * p; 1030 check_frequency(f); 1031 } 1032 _freqs.at_put_grow(n->_idx, (float)f, -1); 1033 _stack.pop(); 1034 } else { 1035 float prev_f = _freqs_stack.pop(); 1036 float new_f = f; 1037 f = new_f + prev_f; 1038 check_frequency(f); 1039 uint i = _stack.index(); 1040 if (i < n->req()) { 1041 c = n->in(i); 1042 _stack.set_index(i+1); 1043 _freqs_stack.push(f); 1044 } else { 1045 _freqs.at_put_grow(n->_idx, f, -1); 1046 _stack.pop(); 1047 } 1048 } 1049 } 1050 if (_stack.size() == 0) { 1051 set_rounding(FE_TONEAREST); 1052 check_frequency(f); 1053 return f; 1054 } 1055 } else if (c->is_Loop()) { 1056 ShouldNotReachHere(); 1057 c = c->in(LoopNode::EntryControl); 1058 } else if (c->is_Region()) { 1059 _freqs_stack.push(0); 1060 _stack.push(c, 2); 1061 c = c->in(1); 1062 } else { 1063 if (c->is_IfProj()) { 1064 IfNode* iff = c->in(0)->as_If(); 1065 if (iff->_prob == PROB_UNKNOWN) { 1066 // assume never taken 1067 _freqs.at_put_grow(c->_idx, 0, -1); 1068 } else if (_phase->get_loop(c) != _phase->get_loop(iff)) { 1069 if (iff->_fcnt == COUNT_UNKNOWN) { 1070 // assume never taken 1071 _freqs.at_put_grow(c->_idx, 0, -1); 1072 } else { 1073 // skip over loop 1074 _stack.push(c, 1); 1075 c = _phase->get_loop(c->in(0))->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl); 1076 } 1077 } else { 1078 _stack.push(c, 1); 1079 c = iff; 1080 } 1081 } else if (c->is_JumpProj()) { 1082 JumpNode* jmp = c->in(0)->as_Jump(); 1083 if (_phase->get_loop(c) != _phase->get_loop(jmp)) { 1084 if (jmp->_fcnt == COUNT_UNKNOWN) { 1085 // assume never taken 1086 _freqs.at_put_grow(c->_idx, 0, -1); 1087 } else { 1088 // skip over loop 1089 _stack.push(c, 1); 1090 c = _phase->get_loop(c->in(0))->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl); 1091 } 1092 } else { 1093 _stack.push(c, 1); 1094 c = jmp; 1095 } 1096 } else if (c->Opcode() == Op_CatchProj && 1097 c->in(0)->Opcode() == Op_Catch && 1098 c->in(0)->in(0)->is_Proj() && 1099 c->in(0)->in(0)->in(0)->is_Call()) { 1100 // assume exceptions are never thrown 1101 uint con = c->as_Proj()->_con; 1102 if (con == CatchProjNode::fall_through_index) { 1103 Node* call = c->in(0)->in(0)->in(0)->in(0); 1104 if (_phase->get_loop(call) != _phase->get_loop(c)) { 1105 _freqs.at_put_grow(c->_idx, 0, -1); 1106 } else { 1107 c = call; 1108 } 1109 } else { 1110 assert(con >= CatchProjNode::catch_all_index, "what else?"); 1111 _freqs.at_put_grow(c->_idx, 0, -1); 1112 } 1113 } else if (c->unique_ctrl_out() == NULL && !c->is_If() && !c->is_Jump()) { 1114 ShouldNotReachHere(); 1115 } else { 1116 c = c->in(0); 1117 } 1118 } 1119 } 1120 ShouldNotReachHere(); 1121 return -1; 1122 } 1123 }; 1124 1125 void PhaseIdealLoop::loop_predication_follow_branches(Node *n, IdealLoopTree *loop, float loop_trip_cnt, 1126 PathFrequency& pf, Node_Stack& stack, VectorSet& seen, 1127 Node_List& if_proj_list) { 1128 assert(n->is_Region(), "start from a region"); 1129 Node* tail = loop->tail(); 1130 stack.push(n, 1); 1131 do { 1132 Node* c = stack.node(); 1133 assert(c->is_Region() || c->is_IfProj(), "only region here"); 1134 uint i = stack.index(); 1135 1136 if (i < c->req()) { 1137 stack.set_index(i+1); 1138 Node* in = c->in(i); 1139 while (!is_dominator(in, tail) && !seen.test_set(in->_idx)) { 1140 IdealLoopTree* in_loop = get_loop(in); 1141 if (in_loop != loop) { 1142 in = in_loop->_head->in(LoopNode::EntryControl); 1143 } else if (in->is_Region()) { 1144 stack.push(in, 1); 1145 break; 1146 } else if (in->is_IfProj() && 1147 in->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none) && 1148 (in->in(0)->Opcode() == Op_If || 1149 in->in(0)->Opcode() == Op_RangeCheck)) { 1150 if (pf.to(in) * loop_trip_cnt >= 1) { 1151 stack.push(in, 1); 1152 } 1153 in = in->in(0); 1154 } else { 1155 in = in->in(0); 1156 } 1157 } 1158 } else { 1159 if (c->is_IfProj()) { 1160 if_proj_list.push(c); 1161 } 1162 stack.pop(); 1163 } 1164 1165 } while (stack.size() > 0); 1166 } 1167 1168 1169 bool PhaseIdealLoop::loop_predication_impl_helper(IdealLoopTree *loop, ProjNode* proj, ProjNode *predicate_proj, 1170 CountedLoopNode *cl, ConNode* zero, Invariance& invar, 1171 Deoptimization::DeoptReason reason) { 1172 // Following are changed to nonnull when a predicate can be hoisted 1173 ProjNode* new_predicate_proj = NULL; 1174 IfNode* iff = proj->in(0)->as_If(); 1175 Node* test = iff->in(1); 1176 if (!test->is_Bool()){ //Conv2B, ... 1177 return false; 1178 } 1179 BoolNode* bol = test->as_Bool(); 1180 if (invar.is_invariant(bol)) { 1181 // Invariant test 1182 new_predicate_proj = create_new_if_for_predicate(predicate_proj, NULL, 1183 reason, 1184 iff->Opcode()); 1185 Node* ctrl = new_predicate_proj->in(0)->as_If()->in(0); 1186 BoolNode* new_predicate_bol = invar.clone(bol, ctrl)->as_Bool(); 1187 1188 // Negate test if necessary 1189 bool negated = false; 1190 if (proj->_con != predicate_proj->_con) { 1191 new_predicate_bol = new BoolNode(new_predicate_bol->in(1), new_predicate_bol->_test.negate()); 1192 register_new_node(new_predicate_bol, ctrl); 1193 negated = true; 1194 } 1195 IfNode* new_predicate_iff = new_predicate_proj->in(0)->as_If(); 1196 _igvn.hash_delete(new_predicate_iff); 1197 new_predicate_iff->set_req(1, new_predicate_bol); 1198 #ifndef PRODUCT 1199 if (TraceLoopPredicate) { 1200 tty->print("Predicate invariant if%s: %d ", negated ? " negated" : "", new_predicate_iff->_idx); 1201 loop->dump_head(); 1202 } else if (TraceLoopOpts) { 1203 tty->print("Predicate IC "); 1204 loop->dump_head(); 1205 } 1206 #endif 1207 } else if (cl != NULL && loop->is_range_check_if(iff, this, invar)) { 1208 // Range check for counted loops 1209 const Node* cmp = bol->in(1)->as_Cmp(); 1210 Node* idx = cmp->in(1); 1211 assert(!invar.is_invariant(idx), "index is variant"); 1212 Node* rng = cmp->in(2); 1213 assert(rng->Opcode() == Op_LoadRange || iff->is_RangeCheck() || _igvn.type(rng)->is_int()->_lo >= 0, "must be"); 1214 assert(invar.is_invariant(rng), "range must be invariant"); 1215 int scale = 1; 1216 Node* offset = zero; 1217 bool ok = is_scaled_iv_plus_offset(idx, cl->phi(), &scale, &offset); 1218 assert(ok, "must be index expression"); 1219 1220 Node* init = cl->init_trip(); 1221 // Limit is not exact. 1222 // Calculate exact limit here. 1223 // Note, counted loop's test is '<' or '>'. 1224 Node* limit = exact_limit(loop); 1225 int stride = cl->stride()->get_int(); 1226 1227 // Build if's for the upper and lower bound tests. The 1228 // lower_bound test will dominate the upper bound test and all 1229 // cloned or created nodes will use the lower bound test as 1230 // their declared control. 1231 1232 // Perform cloning to keep Invariance state correct since the 1233 // late schedule will place invariant things in the loop. 1234 Node *ctrl = predicate_proj->in(0)->as_If()->in(0); 1235 rng = invar.clone(rng, ctrl); 1236 if (offset && offset != zero) { 1237 assert(invar.is_invariant(offset), "offset must be loop invariant"); 1238 offset = invar.clone(offset, ctrl); 1239 } 1240 // If predicate expressions may overflow in the integer range, longs are used. 1241 bool overflow = false; 1242 1243 // Test the lower bound 1244 BoolNode* lower_bound_bol = rc_predicate(loop, ctrl, scale, offset, init, limit, stride, rng, false, overflow); 1245 // Negate test if necessary 1246 bool negated = false; 1247 if (proj->_con != predicate_proj->_con) { 1248 lower_bound_bol = new BoolNode(lower_bound_bol->in(1), lower_bound_bol->_test.negate()); 1249 register_new_node(lower_bound_bol, ctrl); 1250 negated = true; 1251 } 1252 ProjNode* lower_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, reason, overflow ? Op_If : iff->Opcode()); 1253 IfNode* lower_bound_iff = lower_bound_proj->in(0)->as_If(); 1254 _igvn.hash_delete(lower_bound_iff); 1255 lower_bound_iff->set_req(1, lower_bound_bol); 1256 if (TraceLoopPredicate) tty->print_cr("lower bound check if: %s %d ", negated ? " negated" : "", lower_bound_iff->_idx); 1257 1258 // Test the upper bound 1259 BoolNode* upper_bound_bol = rc_predicate(loop, lower_bound_proj, scale, offset, init, limit, stride, rng, true, overflow); 1260 negated = false; 1261 if (proj->_con != predicate_proj->_con) { 1262 upper_bound_bol = new BoolNode(upper_bound_bol->in(1), upper_bound_bol->_test.negate()); 1263 register_new_node(upper_bound_bol, ctrl); 1264 negated = true; 1265 } 1266 ProjNode* upper_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, reason, overflow ? Op_If : iff->Opcode()); 1267 assert(upper_bound_proj->in(0)->as_If()->in(0) == lower_bound_proj, "should dominate"); 1268 IfNode* upper_bound_iff = upper_bound_proj->in(0)->as_If(); 1269 _igvn.hash_delete(upper_bound_iff); 1270 upper_bound_iff->set_req(1, upper_bound_bol); 1271 if (TraceLoopPredicate) tty->print_cr("upper bound check if: %s %d ", negated ? " negated" : "", lower_bound_iff->_idx); 1272 1273 // Fall through into rest of the clean up code which will move 1274 // any dependent nodes onto the upper bound test. 1275 new_predicate_proj = upper_bound_proj; 1276 1277 if (iff->is_RangeCheck()) { 1278 new_predicate_proj = insert_skeleton_predicate(iff, loop, proj, predicate_proj, upper_bound_proj, scale, offset, init, limit, stride, rng, overflow, reason); 1279 } 1280 1281 #ifndef PRODUCT 1282 if (TraceLoopOpts && !TraceLoopPredicate) { 1283 tty->print("Predicate RC "); 1284 loop->dump_head(); 1285 } 1286 #endif 1287 } else { 1288 // Loop variant check (for example, range check in non-counted loop) 1289 // with uncommon trap. 1290 return false; 1291 } 1292 assert(new_predicate_proj != NULL, "sanity"); 1293 // Success - attach condition (new_predicate_bol) to predicate if 1294 invar.map_ctrl(proj, new_predicate_proj); // so that invariance test can be appropriate 1295 1296 // Eliminate the old If in the loop body 1297 dominated_by( new_predicate_proj, iff, proj->_con != new_predicate_proj->_con ); 1298 1299 C->set_major_progress(); 1300 return true; 1301 } 1302 1303 1304 // After pre/main/post loops are created, we'll put a copy of some 1305 // range checks between the pre and main loop to validate the value 1306 // of the main loop induction variable. Make a copy of the predicates 1307 // here with an opaque node as a place holder for the value (will be 1308 // updated by PhaseIdealLoop::update_skeleton_predicate()). 1309 ProjNode* PhaseIdealLoop::insert_skeleton_predicate(IfNode* iff, IdealLoopTree *loop, 1310 ProjNode* proj, ProjNode *predicate_proj, 1311 ProjNode* upper_bound_proj, 1312 int scale, Node* offset, 1313 Node* init, Node* limit, jint stride, 1314 Node* rng, bool &overflow, 1315 Deoptimization::DeoptReason reason) { 1316 assert(proj->_con && predicate_proj->_con, "not a range check?"); 1317 Node* opaque_init = new Opaque1Node(C, init); 1318 register_new_node(opaque_init, upper_bound_proj); 1319 BoolNode* bol = rc_predicate(loop, upper_bound_proj, scale, offset, opaque_init, limit, stride, rng, (stride > 0) != (scale > 0), overflow); 1320 Node* opaque_bol = new Opaque4Node(C, bol, _igvn.intcon(1)); // This will go away once loop opts are over 1321 register_new_node(opaque_bol, upper_bound_proj); 1322 ProjNode* new_proj = create_new_if_for_predicate(predicate_proj, NULL, reason, overflow ? Op_If : iff->Opcode()); 1323 _igvn.replace_input_of(new_proj->in(0), 1, opaque_bol); 1324 assert(opaque_init->outcnt() > 0, "should be used"); 1325 return new_proj; 1326 } 1327 1328 //------------------------------ loop_predication_impl-------------------------- 1329 // Insert loop predicates for null checks and range checks 1330 bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree *loop) { 1331 if (!UseLoopPredicate) return false; 1332 1333 if (!loop->_head->is_Loop()) { 1334 // Could be a simple region when irreducible loops are present. 1335 return false; 1336 } 1337 LoopNode* head = loop->_head->as_Loop(); 1338 1339 if (head->unique_ctrl_out()->Opcode() == Op_NeverBranch) { 1340 // do nothing for infinite loops 1341 return false; 1342 } 1343 1344 if (head->is_OuterStripMinedLoop()) { 1345 return false; 1346 } 1347 1348 CountedLoopNode *cl = NULL; 1349 if (head->is_valid_counted_loop()) { 1350 cl = head->as_CountedLoop(); 1351 // do nothing for iteration-splitted loops 1352 if (!cl->is_normal_loop()) return false; 1353 // Avoid RCE if Counted loop's test is '!='. 1354 BoolTest::mask bt = cl->loopexit()->test_trip(); 1355 if (bt != BoolTest::lt && bt != BoolTest::gt) 1356 cl = NULL; 1357 } 1358 1359 Node* entry = head->skip_strip_mined()->in(LoopNode::EntryControl); 1360 ProjNode *loop_limit_proj = NULL; 1361 ProjNode *predicate_proj = NULL; 1362 ProjNode *profile_predicate_proj = NULL; 1363 // Loop limit check predicate should be near the loop. 1364 loop_limit_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); 1365 if (loop_limit_proj != NULL) { 1366 entry = skip_loop_predicates(loop_limit_proj); 1367 } 1368 bool has_profile_predicates = false; 1369 profile_predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_profile_predicate); 1370 if (profile_predicate_proj != NULL) { 1371 Node* n = skip_loop_predicates(entry); 1372 // Check if predicates were already added to the profile predicate 1373 // block 1374 if (n != entry->in(0)->in(0) || n->outcnt() != 1) { 1375 has_profile_predicates = true; 1376 } 1377 entry = n; 1378 } 1379 predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); 1380 1381 float loop_trip_cnt = -1; 1382 bool follow_branches = loop_predication_should_follow_branches(loop, profile_predicate_proj, loop_trip_cnt); 1383 assert(!follow_branches || loop_trip_cnt >= 0, "negative trip count?"); 1384 1385 if (predicate_proj == NULL && !follow_branches) { 1386 #ifndef PRODUCT 1387 if (TraceLoopPredicate) { 1388 tty->print("missing predicate:"); 1389 loop->dump_head(); 1390 head->dump(1); 1391 } 1392 #endif 1393 return false; 1394 } 1395 ConNode* zero = _igvn.intcon(0); 1396 set_ctrl(zero, C->root()); 1397 1398 ResourceArea *area = Thread::current()->resource_area(); 1399 Invariance invar(area, loop); 1400 1401 // Create list of if-projs such that a newer proj dominates all older 1402 // projs in the list, and they all dominate loop->tail() 1403 Node_List if_proj_list(area); 1404 Node_List regions(area); 1405 Node *current_proj = loop->tail(); //start from tail 1406 1407 1408 Node_List controls(area); 1409 while (current_proj != head) { 1410 if (loop == get_loop(current_proj) && // still in the loop ? 1411 current_proj->is_Proj() && // is a projection ? 1412 (current_proj->in(0)->Opcode() == Op_If || 1413 current_proj->in(0)->Opcode() == Op_RangeCheck)) { // is a if projection ? 1414 if_proj_list.push(current_proj); 1415 } 1416 if (follow_branches && 1417 current_proj->Opcode() == Op_Region && 1418 loop == get_loop(current_proj)) { 1419 regions.push(current_proj); 1420 } 1421 current_proj = idom(current_proj); 1422 } 1423 1424 bool hoisted = false; // true if at least one proj is promoted 1425 1426 if (!has_profile_predicates) { 1427 while (if_proj_list.size() > 0) { 1428 Node* n = if_proj_list.pop(); 1429 1430 ProjNode* proj = n->as_Proj(); 1431 IfNode* iff = proj->in(0)->as_If(); 1432 1433 CallStaticJavaNode* call = proj->is_uncommon_trap_if_pattern(Deoptimization::Reason_none); 1434 if (call == NULL) { 1435 if (loop->is_loop_exit(iff)) { 1436 // stop processing the remaining projs in the list because the execution of them 1437 // depends on the condition of "iff" (iff->in(1)). 1438 break; 1439 } else { 1440 // Both arms are inside the loop. There are two cases: 1441 // (1) there is one backward branch. In this case, any remaining proj 1442 // in the if_proj list post-dominates "iff". So, the condition of "iff" 1443 // does not determine the execution the remining projs directly, and we 1444 // can safely continue. 1445 // (2) both arms are forwarded, i.e. a diamond shape. In this case, "proj" 1446 // does not dominate loop->tail(), so it can not be in the if_proj list. 1447 continue; 1448 } 1449 } 1450 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(call->uncommon_trap_request()); 1451 if (reason == Deoptimization::Reason_predicate) { 1452 break; 1453 } 1454 1455 if (predicate_proj != NULL) { 1456 hoisted = loop_predication_impl_helper(loop, proj, predicate_proj, cl, zero, invar, Deoptimization::Reason_predicate) | hoisted; 1457 } 1458 } // end while 1459 } 1460 1461 Node_List if_proj_list_freq(area); 1462 if (follow_branches) { 1463 PathFrequency pf(loop->_head, this); 1464 1465 // Some projections were skipped by regular predicates because of 1466 // an early loop exit. Try them with profile data. 1467 while (if_proj_list.size() > 0) { 1468 Node* proj = if_proj_list.pop(); 1469 float f = pf.to(proj); 1470 if (proj->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none) && 1471 f * loop_trip_cnt >= 1) { 1472 hoisted = loop_predication_impl_helper(loop, proj->as_Proj(), profile_predicate_proj, cl, zero, invar, Deoptimization::Reason_profile_predicate) | hoisted; 1473 } 1474 } 1475 1476 // And look into all branches 1477 Node_Stack stack(0); 1478 VectorSet seen(Thread::current()->resource_area()); 1479 while (regions.size() > 0) { 1480 Node* c = regions.pop(); 1481 loop_predication_follow_branches(c, loop, loop_trip_cnt, pf, stack, seen, if_proj_list_freq); 1482 } 1483 1484 for (uint i = 0; i < if_proj_list_freq.size(); i++) { 1485 ProjNode* proj = if_proj_list_freq.at(i)->as_Proj(); 1486 hoisted = loop_predication_impl_helper(loop, proj, profile_predicate_proj, cl, zero, invar, Deoptimization::Reason_profile_predicate) | hoisted; 1487 } 1488 } 1489 1490 #ifndef PRODUCT 1491 // report that the loop predication has been actually performed 1492 // for this loop 1493 if (TraceLoopPredicate && hoisted) { 1494 tty->print("Loop Predication Performed:"); 1495 loop->dump_head(); 1496 } 1497 #endif 1498 1499 head->verify_strip_mined(1); 1500 1501 return hoisted; 1502 } 1503 1504 //------------------------------loop_predication-------------------------------- 1505 // driver routine for loop predication optimization 1506 bool IdealLoopTree::loop_predication( PhaseIdealLoop *phase) { 1507 bool hoisted = false; 1508 // Recursively promote predicates 1509 if (_child) { 1510 hoisted = _child->loop_predication( phase); 1511 } 1512 1513 // self 1514 if (!_irreducible && !tail()->is_top()) { 1515 hoisted |= phase->loop_predication_impl(this); 1516 } 1517 1518 if (_next) { //sibling 1519 hoisted |= _next->loop_predication( phase); 1520 } 1521 1522 return hoisted; 1523 }