1 /* 2 * Copyright (c) 2000, 2025, 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 "ci/ciTypeFlow.hpp" 26 #include "memory/allocation.inline.hpp" 27 #include "memory/resourceArea.hpp" 28 #include "opto/addnode.hpp" 29 #include "opto/castnode.hpp" 30 #include "opto/cfgnode.hpp" 31 #include "opto/connode.hpp" 32 #include "opto/loopnode.hpp" 33 #include "opto/phaseX.hpp" 34 #include "opto/predicates.hpp" 35 #include "opto/runtime.hpp" 36 #include "opto/rootnode.hpp" 37 #include "opto/subnode.hpp" 38 #include "opto/subtypenode.hpp" 39 40 // Portions of code courtesy of Clifford Click 41 42 // Optimization - Graph Style 43 44 45 #ifndef PRODUCT 46 extern uint explicit_null_checks_elided; 47 #endif 48 49 IfNode::IfNode(Node* control, Node* bol, float p, float fcnt) 50 : MultiBranchNode(2), 51 _prob(p), 52 _fcnt(fcnt), 53 _assertion_predicate_type(AssertionPredicateType::None) { 54 init_node(control, bol); 55 } 56 57 IfNode::IfNode(Node* control, Node* bol, float p, float fcnt, AssertionPredicateType assertion_predicate_type) 58 : MultiBranchNode(2), 59 _prob(p), 60 _fcnt(fcnt), 61 _assertion_predicate_type(assertion_predicate_type) { 62 init_node(control, bol); 63 } 64 65 //============================================================================= 66 //------------------------------Value------------------------------------------ 67 // Return a tuple for whichever arm of the IF is reachable 68 const Type* IfNode::Value(PhaseGVN* phase) const { 69 if( !in(0) ) return Type::TOP; 70 if( phase->type(in(0)) == Type::TOP ) 71 return Type::TOP; 72 const Type *t = phase->type(in(1)); 73 if( t == Type::TOP ) // data is undefined 74 return TypeTuple::IFNEITHER; // unreachable altogether 75 if( t == TypeInt::ZERO ) // zero, or false 76 return TypeTuple::IFFALSE; // only false branch is reachable 77 if( t == TypeInt::ONE ) // 1, or true 78 return TypeTuple::IFTRUE; // only true branch is reachable 79 assert( t == TypeInt::BOOL, "expected boolean type" ); 80 81 return TypeTuple::IFBOTH; // No progress 82 } 83 84 const RegMask &IfNode::out_RegMask() const { 85 return RegMask::Empty; 86 } 87 88 //------------------------------split_if--------------------------------------- 89 // Look for places where we merge constants, then test on the merged value. 90 // If the IF test will be constant folded on the path with the constant, we 91 // win by splitting the IF to before the merge point. 92 static Node* split_if(IfNode *iff, PhaseIterGVN *igvn) { 93 // I could be a lot more general here, but I'm trying to squeeze this 94 // in before the Christmas '98 break so I'm gonna be kinda restrictive 95 // on the patterns I accept. CNC 96 97 // Look for a compare of a constant and a merged value 98 Node *i1 = iff->in(1); 99 if( !i1->is_Bool() ) return nullptr; 100 BoolNode *b = i1->as_Bool(); 101 Node *cmp = b->in(1); 102 if( !cmp->is_Cmp() ) return nullptr; 103 i1 = cmp->in(1); 104 if( i1 == nullptr || !i1->is_Phi() ) return nullptr; 105 PhiNode *phi = i1->as_Phi(); 106 Node *con2 = cmp->in(2); 107 if( !con2->is_Con() ) return nullptr; 108 // See that the merge point contains some constants 109 Node *con1=nullptr; 110 uint i4; 111 RegionNode* phi_region = phi->region(); 112 for (i4 = 1; i4 < phi->req(); i4++ ) { 113 con1 = phi->in(i4); 114 // Do not optimize partially collapsed merges 115 if (con1 == nullptr || phi_region->in(i4) == nullptr || igvn->type(phi_region->in(i4)) == Type::TOP) { 116 igvn->_worklist.push(iff); 117 return nullptr; 118 } 119 if( con1->is_Con() ) break; // Found a constant 120 // Also allow null-vs-not-null checks 121 const TypePtr *tp = igvn->type(con1)->isa_ptr(); 122 if( tp && tp->_ptr == TypePtr::NotNull ) 123 break; 124 } 125 if( i4 >= phi->req() ) return nullptr; // Found no constants 126 127 igvn->C->set_has_split_ifs(true); // Has chance for split-if 128 129 // Make sure that the compare can be constant folded away 130 Node *cmp2 = cmp->clone(); 131 cmp2->set_req(1,con1); 132 cmp2->set_req(2,con2); 133 const Type *t = cmp2->Value(igvn); 134 // This compare is dead, so whack it! 135 igvn->remove_dead_node(cmp2); 136 if( !t->singleton() ) return nullptr; 137 138 // No intervening control, like a simple Call 139 Node* r = iff->in(0); 140 if (!r->is_Region() || r->is_Loop() || phi_region != r || r->as_Region()->is_copy()) { 141 return nullptr; 142 } 143 144 // No other users of the cmp/bool 145 if (b->outcnt() != 1 || cmp->outcnt() != 1) { 146 //tty->print_cr("many users of cmp/bool"); 147 return nullptr; 148 } 149 150 // Make sure we can determine where all the uses of merged values go 151 for (DUIterator_Fast jmax, j = r->fast_outs(jmax); j < jmax; j++) { 152 Node* u = r->fast_out(j); 153 if( u == r ) continue; 154 if( u == iff ) continue; 155 if( u->outcnt() == 0 ) continue; // use is dead & ignorable 156 if( !u->is_Phi() ) { 157 /* 158 if( u->is_Start() ) { 159 tty->print_cr("Region has inlined start use"); 160 } else { 161 tty->print_cr("Region has odd use"); 162 u->dump(2); 163 }*/ 164 return nullptr; 165 } 166 if( u != phi ) { 167 // CNC - do not allow any other merged value 168 //tty->print_cr("Merging another value"); 169 //u->dump(2); 170 return nullptr; 171 } 172 // Make sure we can account for all Phi uses 173 for (DUIterator_Fast kmax, k = u->fast_outs(kmax); k < kmax; k++) { 174 Node* v = u->fast_out(k); // User of the phi 175 // CNC - Allow only really simple patterns. 176 // In particular I disallow AddP of the Phi, a fairly common pattern 177 if (v == cmp) continue; // The compare is OK 178 if (v->is_ConstraintCast()) { 179 // If the cast is derived from data flow edges, it may not have a control edge. 180 // If so, it should be safe to split. But follow-up code can not deal with 181 // this (l. 359). So skip. 182 if (v->in(0) == nullptr) { 183 return nullptr; 184 } 185 if (v->in(0)->in(0) == iff) { 186 continue; // CastPP/II of the IfNode is OK 187 } 188 } 189 // Disabled following code because I cannot tell if exactly one 190 // path dominates without a real dominator check. CNC 9/9/1999 191 //uint vop = v->Opcode(); 192 //if( vop == Op_Phi ) { // Phi from another merge point might be OK 193 // Node *r = v->in(0); // Get controlling point 194 // if( !r ) return nullptr; // Degraded to a copy 195 // // Find exactly one path in (either True or False doms, but not IFF) 196 // int cnt = 0; 197 // for( uint i = 1; i < r->req(); i++ ) 198 // if( r->in(i) && r->in(i)->in(0) == iff ) 199 // cnt++; 200 // if( cnt == 1 ) continue; // Exactly one of True or False guards Phi 201 //} 202 if( !v->is_Call() ) { 203 /* 204 if( v->Opcode() == Op_AddP ) { 205 tty->print_cr("Phi has AddP use"); 206 } else if( v->Opcode() == Op_CastPP ) { 207 tty->print_cr("Phi has CastPP use"); 208 } else if( v->Opcode() == Op_CastII ) { 209 tty->print_cr("Phi has CastII use"); 210 } else { 211 tty->print_cr("Phi has use I can't be bothered with"); 212 } 213 */ 214 } 215 return nullptr; 216 217 /* CNC - Cut out all the fancy acceptance tests 218 // Can we clone this use when doing the transformation? 219 // If all uses are from Phis at this merge or constants, then YES. 220 if( !v->in(0) && v != cmp ) { 221 tty->print_cr("Phi has free-floating use"); 222 v->dump(2); 223 return nullptr; 224 } 225 for( uint l = 1; l < v->req(); l++ ) { 226 if( (!v->in(l)->is_Phi() || v->in(l)->in(0) != r) && 227 !v->in(l)->is_Con() ) { 228 tty->print_cr("Phi has use"); 229 v->dump(2); 230 return nullptr; 231 } // End of if Phi-use input is neither Phi nor Constant 232 } // End of for all inputs to Phi-use 233 */ 234 } // End of for all uses of Phi 235 } // End of for all uses of Region 236 237 // Only do this if the IF node is in a sane state 238 if (iff->outcnt() != 2) 239 return nullptr; 240 241 // Got a hit! Do the Mondo Hack! 242 // 243 //ABC a1c def ghi B 1 e h A C a c d f g i 244 // R - Phi - Phi - Phi Rc - Phi - Phi - Phi Rx - Phi - Phi - Phi 245 // cmp - 2 cmp - 2 cmp - 2 246 // bool bool_c bool_x 247 // if if_c if_x 248 // T F T F T F 249 // ..s.. ..t .. ..s.. ..t.. ..s.. ..t.. 250 // 251 // Split the paths coming into the merge point into 2 separate groups of 252 // merges. On the left will be all the paths feeding constants into the 253 // Cmp's Phi. On the right will be the remaining paths. The Cmp's Phi 254 // will fold up into a constant; this will let the Cmp fold up as well as 255 // all the control flow. Below the original IF we have 2 control 256 // dependent regions, 's' and 't'. Now we will merge the two paths 257 // just prior to 's' and 't' from the two IFs. At least 1 path (and quite 258 // likely 2 or more) will promptly constant fold away. 259 PhaseGVN *phase = igvn; 260 261 // Make a region merging constants and a region merging the rest 262 uint req_c = 0; 263 for (uint ii = 1; ii < r->req(); ii++) { 264 if (phi->in(ii) == con1) { 265 req_c++; 266 } 267 if (Node::may_be_loop_entry(r->in(ii))) { 268 // Bail out if splitting through a region with a Parse Predicate input (could 269 // also be a loop header before loop opts creates a LoopNode for it). 270 return nullptr; 271 } 272 } 273 274 // If all the defs of the phi are the same constant, we already have the desired end state. 275 // Skip the split that would create empty phi and region nodes. 276 if ((r->req() - req_c) == 1) { 277 return nullptr; 278 } 279 280 // At this point we know that we can apply the split if optimization. If the region is still on the worklist, 281 // we should wait until it is processed. The region might be removed which makes this optimization redundant. 282 // This also avoids the creation of dead data loops when rewiring data nodes below when a region is dying. 283 if (igvn->_worklist.member(r)) { 284 igvn->_worklist.push(iff); // retry split if later again 285 return nullptr; 286 } 287 288 Node *region_c = new RegionNode(req_c + 1); 289 Node *phi_c = con1; 290 uint len = r->req(); 291 Node *region_x = new RegionNode(len - req_c); 292 Node *phi_x = PhiNode::make_blank(region_x, phi); 293 for (uint i = 1, i_c = 1, i_x = 1; i < len; i++) { 294 if (phi->in(i) == con1) { 295 region_c->init_req( i_c++, r ->in(i) ); 296 } else { 297 region_x->init_req( i_x, r ->in(i) ); 298 phi_x ->init_req( i_x++, phi->in(i) ); 299 } 300 } 301 302 // Register the new RegionNodes but do not transform them. Cannot 303 // transform until the entire Region/Phi conglomerate has been hacked 304 // as a single huge transform. 305 igvn->register_new_node_with_optimizer( region_c ); 306 igvn->register_new_node_with_optimizer( region_x ); 307 // Prevent the untimely death of phi_x. Currently he has no uses. He is 308 // about to get one. If this only use goes away, then phi_x will look dead. 309 // However, he will be picking up some more uses down below. 310 Node *hook = new Node(4); 311 hook->init_req(0, phi_x); 312 hook->init_req(1, phi_c); 313 phi_x = phase->transform( phi_x ); 314 315 // Make the compare 316 Node *cmp_c = phase->makecon(t); 317 Node *cmp_x = cmp->clone(); 318 cmp_x->set_req(1,phi_x); 319 cmp_x->set_req(2,con2); 320 cmp_x = phase->transform(cmp_x); 321 // Make the bool 322 Node *b_c = phase->transform(new BoolNode(cmp_c,b->_test._test)); 323 Node *b_x = phase->transform(new BoolNode(cmp_x,b->_test._test)); 324 // Make the IfNode 325 IfNode* iff_c = iff->clone()->as_If(); 326 iff_c->set_req(0, region_c); 327 iff_c->set_req(1, b_c); 328 igvn->set_type_bottom(iff_c); 329 igvn->_worklist.push(iff_c); 330 hook->init_req(2, iff_c); 331 332 IfNode* iff_x = iff->clone()->as_If(); 333 iff_x->set_req(0, region_x); 334 iff_x->set_req(1, b_x); 335 igvn->set_type_bottom(iff_x); 336 igvn->_worklist.push(iff_x); 337 hook->init_req(3, iff_x); 338 339 // Make the true/false arms 340 Node *iff_c_t = phase->transform(new IfTrueNode (iff_c)); 341 Node *iff_c_f = phase->transform(new IfFalseNode(iff_c)); 342 Node *iff_x_t = phase->transform(new IfTrueNode (iff_x)); 343 Node *iff_x_f = phase->transform(new IfFalseNode(iff_x)); 344 345 // Merge the TRUE paths 346 Node *region_s = new RegionNode(3); 347 igvn->_worklist.push(region_s); 348 region_s->init_req(1, iff_c_t); 349 region_s->init_req(2, iff_x_t); 350 igvn->register_new_node_with_optimizer( region_s ); 351 352 // Merge the FALSE paths 353 Node *region_f = new RegionNode(3); 354 igvn->_worklist.push(region_f); 355 region_f->init_req(1, iff_c_f); 356 region_f->init_req(2, iff_x_f); 357 igvn->register_new_node_with_optimizer( region_f ); 358 359 igvn->hash_delete(cmp);// Remove soon-to-be-dead node from hash table. 360 cmp->set_req(1,nullptr); // Whack the inputs to cmp because it will be dead 361 cmp->set_req(2,nullptr); 362 // Check for all uses of the Phi and give them a new home. 363 // The 'cmp' got cloned, but CastPP/IIs need to be moved. 364 Node *phi_s = nullptr; // do not construct unless needed 365 Node *phi_f = nullptr; // do not construct unless needed 366 for (DUIterator_Last i2min, i2 = phi->last_outs(i2min); i2 >= i2min; --i2) { 367 Node* v = phi->last_out(i2);// User of the phi 368 igvn->rehash_node_delayed(v); // Have to fixup other Phi users 369 uint vop = v->Opcode(); 370 Node *proj = nullptr; 371 if( vop == Op_Phi ) { // Remote merge point 372 Node *r = v->in(0); 373 for (uint i3 = 1; i3 < r->req(); i3++) 374 if (r->in(i3) && r->in(i3)->in(0) == iff) { 375 proj = r->in(i3); 376 break; 377 } 378 } else if( v->is_ConstraintCast() ) { 379 proj = v->in(0); // Controlling projection 380 } else { 381 assert( 0, "do not know how to handle this guy" ); 382 } 383 guarantee(proj != nullptr, "sanity"); 384 385 Node *proj_path_data, *proj_path_ctrl; 386 if( proj->Opcode() == Op_IfTrue ) { 387 if( phi_s == nullptr ) { 388 // Only construct phi_s if needed, otherwise provides 389 // interfering use. 390 phi_s = PhiNode::make_blank(region_s,phi); 391 phi_s->init_req( 1, phi_c ); 392 phi_s->init_req( 2, phi_x ); 393 hook->add_req(phi_s); 394 phi_s = phase->transform(phi_s); 395 } 396 proj_path_data = phi_s; 397 proj_path_ctrl = region_s; 398 } else { 399 if( phi_f == nullptr ) { 400 // Only construct phi_f if needed, otherwise provides 401 // interfering use. 402 phi_f = PhiNode::make_blank(region_f,phi); 403 phi_f->init_req( 1, phi_c ); 404 phi_f->init_req( 2, phi_x ); 405 hook->add_req(phi_f); 406 phi_f = phase->transform(phi_f); 407 } 408 proj_path_data = phi_f; 409 proj_path_ctrl = region_f; 410 } 411 412 // Fixup 'v' for for the split 413 if( vop == Op_Phi ) { // Remote merge point 414 uint i; 415 for( i = 1; i < v->req(); i++ ) 416 if( v->in(i) == phi ) 417 break; 418 v->set_req(i, proj_path_data ); 419 } else if( v->is_ConstraintCast() ) { 420 v->set_req(0, proj_path_ctrl ); 421 v->set_req(1, proj_path_data ); 422 } else 423 ShouldNotReachHere(); 424 } 425 426 // Now replace the original iff's True/False with region_s/region_t. 427 // This makes the original iff go dead. 428 for (DUIterator_Last i3min, i3 = iff->last_outs(i3min); i3 >= i3min; --i3) { 429 Node* p = iff->last_out(i3); 430 assert( p->Opcode() == Op_IfTrue || p->Opcode() == Op_IfFalse, "" ); 431 Node *u = (p->Opcode() == Op_IfTrue) ? region_s : region_f; 432 // Replace p with u 433 igvn->add_users_to_worklist(p); 434 for (DUIterator_Last lmin, l = p->last_outs(lmin); l >= lmin;) { 435 Node* x = p->last_out(l); 436 igvn->hash_delete(x); 437 uint uses_found = 0; 438 for( uint j = 0; j < x->req(); j++ ) { 439 if( x->in(j) == p ) { 440 x->set_req(j, u); 441 uses_found++; 442 } 443 } 444 l -= uses_found; // we deleted 1 or more copies of this edge 445 } 446 igvn->remove_dead_node(p); 447 } 448 449 // Force the original merge dead 450 igvn->hash_delete(r); 451 // First, remove region's dead users. 452 for (DUIterator_Last lmin, l = r->last_outs(lmin); l >= lmin;) { 453 Node* u = r->last_out(l); 454 if( u == r ) { 455 r->set_req(0, nullptr); 456 } else { 457 assert(u->outcnt() == 0, "only dead users"); 458 igvn->remove_dead_node(u); 459 } 460 l -= 1; 461 } 462 igvn->remove_dead_node(r); 463 464 // Now remove the bogus extra edges used to keep things alive 465 igvn->remove_dead_node( hook ); 466 467 // Must return either the original node (now dead) or a new node 468 // (Do not return a top here, since that would break the uniqueness of top.) 469 return new ConINode(TypeInt::ZERO); 470 } 471 472 IfNode* IfNode::make_with_same_profile(IfNode* if_node_profile, Node* ctrl, BoolNode* bol) { 473 // Assert here that we only try to create a clone from an If node with the same profiling if that actually makes sense. 474 // Some If node subtypes should not be cloned in this way. In theory, we should not clone BaseCountedLoopEndNodes. 475 // But they can end up being used as normal If nodes when peeling a loop - they serve as zero-trip guard. 476 // Allow them as well. 477 assert(if_node_profile->Opcode() == Op_If || if_node_profile->is_RangeCheck() 478 || if_node_profile->is_BaseCountedLoopEnd(), "should not clone other nodes"); 479 if (if_node_profile->is_RangeCheck()) { 480 // RangeCheck nodes could be further optimized. 481 return new RangeCheckNode(ctrl, bol, if_node_profile->_prob, if_node_profile->_fcnt); 482 } else { 483 // Not a RangeCheckNode? Fall back to IfNode. 484 return new IfNode(ctrl, bol, if_node_profile->_prob, if_node_profile->_fcnt); 485 } 486 } 487 488 // if this IfNode follows a range check pattern return the projection 489 // for the failed path 490 ProjNode* IfNode::range_check_trap_proj(int& flip_test, Node*& l, Node*& r) { 491 if (outcnt() != 2) { 492 return nullptr; 493 } 494 Node* b = in(1); 495 if (b == nullptr || !b->is_Bool()) return nullptr; 496 BoolNode* bn = b->as_Bool(); 497 Node* cmp = bn->in(1); 498 if (cmp == nullptr) return nullptr; 499 if (cmp->Opcode() != Op_CmpU) return nullptr; 500 501 l = cmp->in(1); 502 r = cmp->in(2); 503 flip_test = 1; 504 if (bn->_test._test == BoolTest::le) { 505 l = cmp->in(2); 506 r = cmp->in(1); 507 flip_test = 2; 508 } else if (bn->_test._test != BoolTest::lt) { 509 return nullptr; 510 } 511 if (l->is_top()) return nullptr; // Top input means dead test 512 if (r->Opcode() != Op_LoadRange && !is_RangeCheck()) return nullptr; 513 514 // We have recognized one of these forms: 515 // Flip 1: If (Bool[<] CmpU(l, LoadRange)) ... 516 // Flip 2: If (Bool[<=] CmpU(LoadRange, l)) ... 517 518 ProjNode* iftrap = proj_out_or_null(flip_test == 2 ? true : false); 519 return iftrap; 520 } 521 522 523 //------------------------------is_range_check--------------------------------- 524 // Return 0 if not a range check. Return 1 if a range check and set index and 525 // offset. Return 2 if we had to negate the test. Index is null if the check 526 // is versus a constant. 527 int RangeCheckNode::is_range_check(Node* &range, Node* &index, jint &offset) { 528 int flip_test = 0; 529 Node* l = nullptr; 530 Node* r = nullptr; 531 ProjNode* iftrap = range_check_trap_proj(flip_test, l, r); 532 533 if (iftrap == nullptr) { 534 return 0; 535 } 536 537 // Make sure it's a real range check by requiring an uncommon trap 538 // along the OOB path. Otherwise, it's possible that the user wrote 539 // something which optimized to look like a range check but behaves 540 // in some other way. 541 if (iftrap->is_uncommon_trap_proj(Deoptimization::Reason_range_check) == nullptr) { 542 return 0; 543 } 544 545 // Look for index+offset form 546 Node* ind = l; 547 jint off = 0; 548 if (l->is_top()) { 549 return 0; 550 } else if (l->Opcode() == Op_AddI) { 551 if ((off = l->in(1)->find_int_con(0)) != 0) { 552 ind = l->in(2)->uncast(); 553 } else if ((off = l->in(2)->find_int_con(0)) != 0) { 554 ind = l->in(1)->uncast(); 555 } 556 } else if ((off = l->find_int_con(-1)) >= 0) { 557 // constant offset with no variable index 558 ind = nullptr; 559 } else { 560 // variable index with no constant offset (or dead negative index) 561 off = 0; 562 } 563 564 // Return all the values: 565 index = ind; 566 offset = off; 567 range = r; 568 return flip_test; 569 } 570 571 //------------------------------adjust_check----------------------------------- 572 // Adjust (widen) a prior range check 573 static void adjust_check(IfProjNode* proj, Node* range, Node* index, 574 int flip, jint off_lo, PhaseIterGVN* igvn) { 575 PhaseGVN *gvn = igvn; 576 // Break apart the old check 577 Node *iff = proj->in(0); 578 Node *bol = iff->in(1); 579 if( bol->is_top() ) return; // In case a partially dead range check appears 580 // bail (or bomb[ASSERT/DEBUG]) if NOT projection-->IfNode-->BoolNode 581 DEBUG_ONLY( if (!bol->is_Bool()) { proj->dump(3); fatal("Expect projection-->IfNode-->BoolNode"); } ) 582 if (!bol->is_Bool()) return; 583 584 Node *cmp = bol->in(1); 585 // Compute a new check 586 Node *new_add = gvn->intcon(off_lo); 587 if (index) { 588 new_add = off_lo ? gvn->transform(new AddINode(index, new_add)) : index; 589 } 590 Node *new_cmp = (flip == 1) 591 ? new CmpUNode(new_add, range) 592 : new CmpUNode(range, new_add); 593 new_cmp = gvn->transform(new_cmp); 594 // See if no need to adjust the existing check 595 if (new_cmp == cmp) return; 596 // Else, adjust existing check 597 Node* new_bol = gvn->transform(new BoolNode(new_cmp, bol->as_Bool()->_test._test)); 598 igvn->rehash_node_delayed(iff); 599 iff->set_req_X(1, new_bol, igvn); 600 // As part of range check smearing, this range check is widened. Loads and range check Cast nodes that are control 601 // dependent on this range check now depend on multiple dominating range checks. These control dependent nodes end up 602 // at the lowest/nearest dominating check in the graph. To ensure that these Loads/Casts do not float above any of the 603 // dominating checks (even when the lowest dominating check is later replaced by yet another dominating check), we 604 // need to pin them at the lowest dominating check. 605 proj->pin_array_access_nodes(igvn); 606 } 607 608 //------------------------------up_one_dom------------------------------------- 609 // Walk up the dominator tree one step. Return null at root or true 610 // complex merges. Skips through small diamonds. 611 Node* IfNode::up_one_dom(Node *curr, bool linear_only) { 612 Node *dom = curr->in(0); 613 if( !dom ) // Found a Region degraded to a copy? 614 return curr->nonnull_req(); // Skip thru it 615 616 if( curr != dom ) // Normal walk up one step? 617 return dom; 618 619 // Use linear_only if we are still parsing, since we cannot 620 // trust the regions to be fully filled in. 621 if (linear_only) 622 return nullptr; 623 624 if( dom->is_Root() ) 625 return nullptr; 626 627 // Else hit a Region. Check for a loop header 628 if( dom->is_Loop() ) 629 return dom->in(1); // Skip up thru loops 630 631 // Check for small diamonds 632 Node *din1, *din2, *din3, *din4; 633 if( dom->req() == 3 && // 2-path merge point 634 (din1 = dom ->in(1)) && // Left path exists 635 (din2 = dom ->in(2)) && // Right path exists 636 (din3 = din1->in(0)) && // Left path up one 637 (din4 = din2->in(0)) ) { // Right path up one 638 if( din3->is_Call() && // Handle a slow-path call on either arm 639 (din3 = din3->in(0)) ) 640 din3 = din3->in(0); 641 if( din4->is_Call() && // Handle a slow-path call on either arm 642 (din4 = din4->in(0)) ) 643 din4 = din4->in(0); 644 if (din3 != nullptr && din3 == din4 && din3->is_If()) // Regions not degraded to a copy 645 return din3; // Skip around diamonds 646 } 647 648 // Give up the search at true merges 649 return nullptr; // Dead loop? Or hit root? 650 } 651 652 653 //------------------------------filtered_int_type-------------------------------- 654 // Return a possibly more restrictive type for val based on condition control flow for an if 655 const TypeInt* IfNode::filtered_int_type(PhaseGVN* gvn, Node* val, Node* if_proj) { 656 assert(if_proj && 657 (if_proj->Opcode() == Op_IfTrue || if_proj->Opcode() == Op_IfFalse), "expecting an if projection"); 658 if (if_proj->in(0) && if_proj->in(0)->is_If()) { 659 IfNode* iff = if_proj->in(0)->as_If(); 660 if (iff->in(1) && iff->in(1)->is_Bool()) { 661 BoolNode* bol = iff->in(1)->as_Bool(); 662 if (bol->in(1) && bol->in(1)->is_Cmp()) { 663 const CmpNode* cmp = bol->in(1)->as_Cmp(); 664 if (cmp->in(1) == val) { 665 const TypeInt* cmp2_t = gvn->type(cmp->in(2))->isa_int(); 666 if (cmp2_t != nullptr) { 667 jint lo = cmp2_t->_lo; 668 jint hi = cmp2_t->_hi; 669 BoolTest::mask msk = if_proj->Opcode() == Op_IfTrue ? bol->_test._test : bol->_test.negate(); 670 switch (msk) { 671 case BoolTest::ne: { 672 // If val is compared to its lower or upper bound, we can narrow the type 673 const TypeInt* val_t = gvn->type(val)->isa_int(); 674 if (val_t != nullptr && !val_t->singleton() && cmp2_t->is_con()) { 675 if (val_t->_lo == lo) { 676 return TypeInt::make(val_t->_lo + 1, val_t->_hi, val_t->_widen); 677 } else if (val_t->_hi == hi) { 678 return TypeInt::make(val_t->_lo, val_t->_hi - 1, val_t->_widen); 679 } 680 } 681 // Can't refine type 682 return nullptr; 683 } 684 case BoolTest::eq: 685 return cmp2_t; 686 case BoolTest::lt: 687 lo = TypeInt::INT->_lo; 688 if (hi != min_jint) { 689 hi = hi - 1; 690 } 691 break; 692 case BoolTest::le: 693 lo = TypeInt::INT->_lo; 694 break; 695 case BoolTest::gt: 696 if (lo != max_jint) { 697 lo = lo + 1; 698 } 699 hi = TypeInt::INT->_hi; 700 break; 701 case BoolTest::ge: 702 // lo unchanged 703 hi = TypeInt::INT->_hi; 704 break; 705 default: 706 break; 707 } 708 const TypeInt* rtn_t = TypeInt::make(lo, hi, cmp2_t->_widen); 709 return rtn_t; 710 } 711 } 712 } 713 } 714 } 715 return nullptr; 716 } 717 718 //------------------------------fold_compares---------------------------- 719 // See if a pair of CmpIs can be converted into a CmpU. In some cases 720 // the direction of this if is determined by the preceding if so it 721 // can be eliminate entirely. 722 // 723 // Given an if testing (CmpI n v) check for an immediately control 724 // dependent if that is testing (CmpI n v2) and has one projection 725 // leading to this if and the other projection leading to a region 726 // that merges one of this ifs control projections. 727 // 728 // If 729 // / | 730 // / | 731 // / | 732 // If | 733 // /\ | 734 // / \ | 735 // / \ | 736 // / Region 737 // 738 // Or given an if testing (CmpI n v) check for a dominating if that is 739 // testing (CmpI n v2), both having one projection leading to an 740 // uncommon trap. Allow Another independent guard in between to cover 741 // an explicit range check: 742 // if (index < 0 || index >= array.length) { 743 // which may need a null check to guard the LoadRange 744 // 745 // If 746 // / \ 747 // / \ 748 // / \ 749 // If unc 750 // /\ 751 // / \ 752 // / \ 753 // / unc 754 // 755 756 // Is the comparison for this If suitable for folding? 757 bool IfNode::cmpi_folds(PhaseIterGVN* igvn, bool fold_ne) { 758 return in(1) != nullptr && 759 in(1)->is_Bool() && 760 in(1)->in(1) != nullptr && 761 in(1)->in(1)->Opcode() == Op_CmpI && 762 in(1)->in(1)->in(2) != nullptr && 763 in(1)->in(1)->in(2) != igvn->C->top() && 764 (in(1)->as_Bool()->_test.is_less() || 765 in(1)->as_Bool()->_test.is_greater() || 766 (fold_ne && in(1)->as_Bool()->_test._test == BoolTest::ne)); 767 } 768 769 // Is a dominating control suitable for folding with this if? 770 bool IfNode::is_ctrl_folds(Node* ctrl, PhaseIterGVN* igvn) { 771 return ctrl != nullptr && 772 ctrl->is_Proj() && 773 ctrl->outcnt() == 1 && // No side-effects 774 ctrl->in(0) != nullptr && 775 ctrl->in(0)->Opcode() == Op_If && 776 ctrl->in(0)->outcnt() == 2 && 777 ctrl->in(0)->as_If()->cmpi_folds(igvn, true) && 778 // Must compare same value 779 ctrl->in(0)->in(1)->in(1)->in(1) != nullptr && 780 ctrl->in(0)->in(1)->in(1)->in(1) != igvn->C->top() && 781 ctrl->in(0)->in(1)->in(1)->in(1) == in(1)->in(1)->in(1); 782 } 783 784 // Do this If and the dominating If share a region? 785 bool IfNode::has_shared_region(ProjNode* proj, ProjNode*& success, ProjNode*& fail) { 786 ProjNode* otherproj = proj->other_if_proj(); 787 Node* otherproj_ctrl_use = otherproj->unique_ctrl_out_or_null(); 788 RegionNode* region = (otherproj_ctrl_use != nullptr && otherproj_ctrl_use->is_Region()) ? otherproj_ctrl_use->as_Region() : nullptr; 789 success = nullptr; 790 fail = nullptr; 791 792 if (otherproj->outcnt() == 1 && region != nullptr && !region->has_phi()) { 793 for (int i = 0; i < 2; i++) { 794 ProjNode* proj = proj_out(i); 795 if (success == nullptr && proj->outcnt() == 1 && proj->unique_out() == region) { 796 success = proj; 797 } else if (fail == nullptr) { 798 fail = proj; 799 } else { 800 success = fail = nullptr; 801 } 802 } 803 } 804 return success != nullptr && fail != nullptr; 805 } 806 807 bool IfNode::is_dominator_unc(CallStaticJavaNode* dom_unc, CallStaticJavaNode* unc) { 808 // Different methods and methods containing jsrs are not supported. 809 ciMethod* method = unc->jvms()->method(); 810 ciMethod* dom_method = dom_unc->jvms()->method(); 811 if (method != dom_method || method->has_jsrs()) { 812 return false; 813 } 814 // Check that both traps are in the same activation of the method (instead 815 // of two activations being inlined through different call sites) by verifying 816 // that the call stacks are equal for both JVMStates. 817 JVMState* dom_caller = dom_unc->jvms()->caller(); 818 JVMState* caller = unc->jvms()->caller(); 819 if ((dom_caller == nullptr) != (caller == nullptr)) { 820 // The current method must either be inlined into both dom_caller and 821 // caller or must not be inlined at all (top method). Bail out otherwise. 822 return false; 823 } else if (dom_caller != nullptr && !dom_caller->same_calls_as(caller)) { 824 return false; 825 } 826 // Check that the bci of the dominating uncommon trap dominates the bci 827 // of the dominated uncommon trap. Otherwise we may not re-execute 828 // the dominated check after deoptimization from the merged uncommon trap. 829 ciTypeFlow* flow = dom_method->get_flow_analysis(); 830 int bci = unc->jvms()->bci(); 831 int dom_bci = dom_unc->jvms()->bci(); 832 if (!flow->is_dominated_by(bci, dom_bci)) { 833 return false; 834 } 835 836 return true; 837 } 838 839 // Return projection that leads to an uncommon trap if any 840 ProjNode* IfNode::uncommon_trap_proj(CallStaticJavaNode*& call, Deoptimization::DeoptReason reason) const { 841 for (int i = 0; i < 2; i++) { 842 call = proj_out(i)->is_uncommon_trap_proj(reason); 843 if (call != nullptr) { 844 return proj_out(i); 845 } 846 } 847 return nullptr; 848 } 849 850 // Do this If and the dominating If both branch out to an uncommon trap 851 bool IfNode::has_only_uncommon_traps(ProjNode* proj, ProjNode*& success, ProjNode*& fail, PhaseIterGVN* igvn) { 852 ProjNode* otherproj = proj->other_if_proj(); 853 CallStaticJavaNode* dom_unc = otherproj->is_uncommon_trap_proj(); 854 855 if (otherproj->outcnt() == 1 && dom_unc != nullptr) { 856 // We need to re-execute the folded Ifs after deoptimization from the merged traps 857 if (!dom_unc->jvms()->should_reexecute()) { 858 return false; 859 } 860 861 CallStaticJavaNode* unc = nullptr; 862 ProjNode* unc_proj = uncommon_trap_proj(unc); 863 if (unc_proj != nullptr && unc_proj->outcnt() == 1) { 864 if (dom_unc == unc) { 865 // Allow the uncommon trap to be shared through a region 866 RegionNode* r = unc->in(0)->as_Region(); 867 if (r->outcnt() != 2 || r->req() != 3 || r->find_edge(otherproj) == -1 || r->find_edge(unc_proj) == -1) { 868 return false; 869 } 870 assert(r->has_phi() == nullptr, "simple region shouldn't have a phi"); 871 } else if (dom_unc->in(0) != otherproj || unc->in(0) != unc_proj) { 872 return false; 873 } 874 875 if (!is_dominator_unc(dom_unc, unc)) { 876 return false; 877 } 878 879 // See merge_uncommon_traps: the reason of the uncommon trap 880 // will be changed and the state of the dominating If will be 881 // used. Checked that we didn't apply this transformation in a 882 // previous compilation and it didn't cause too many traps 883 ciMethod* dom_method = dom_unc->jvms()->method(); 884 int dom_bci = dom_unc->jvms()->bci(); 885 if (!igvn->C->too_many_traps(dom_method, dom_bci, Deoptimization::Reason_unstable_fused_if) && 886 !igvn->C->too_many_traps(dom_method, dom_bci, Deoptimization::Reason_range_check) && 887 // Return true if c2 manages to reconcile with UnstableIf optimization. See the comments for it. 888 igvn->C->remove_unstable_if_trap(dom_unc, true/*yield*/)) { 889 success = unc_proj; 890 fail = unc_proj->other_if_proj(); 891 return true; 892 } 893 } 894 } 895 return false; 896 } 897 898 // Check that the 2 CmpI can be folded into as single CmpU and proceed with the folding 899 bool IfNode::fold_compares_helper(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn) { 900 Node* this_cmp = in(1)->in(1); 901 BoolNode* this_bool = in(1)->as_Bool(); 902 IfNode* dom_iff = proj->in(0)->as_If(); 903 BoolNode* dom_bool = dom_iff->in(1)->as_Bool(); 904 Node* lo = dom_iff->in(1)->in(1)->in(2); 905 Node* hi = this_cmp->in(2); 906 Node* n = this_cmp->in(1); 907 ProjNode* otherproj = proj->other_if_proj(); 908 909 const TypeInt* lo_type = IfNode::filtered_int_type(igvn, n, otherproj); 910 const TypeInt* hi_type = IfNode::filtered_int_type(igvn, n, success); 911 912 BoolTest::mask lo_test = dom_bool->_test._test; 913 BoolTest::mask hi_test = this_bool->_test._test; 914 BoolTest::mask cond = hi_test; 915 916 // convert: 917 // 918 // dom_bool = x {<,<=,>,>=} a 919 // / \ 920 // proj = {True,False} / \ otherproj = {False,True} 921 // / 922 // this_bool = x {<,<=} b 923 // / \ 924 // fail = {True,False} / \ success = {False,True} 925 // / 926 // 927 // (Second test guaranteed canonicalized, first one may not have 928 // been canonicalized yet) 929 // 930 // into: 931 // 932 // cond = (x - lo) {<u,<=u,>u,>=u} adjusted_lim 933 // / \ 934 // fail / \ success 935 // / 936 // 937 938 // Figure out which of the two tests sets the upper bound and which 939 // sets the lower bound if any. 940 Node* adjusted_lim = nullptr; 941 if (lo_type != nullptr && hi_type != nullptr && hi_type->_lo > lo_type->_hi && 942 hi_type->_hi == max_jint && lo_type->_lo == min_jint && lo_test != BoolTest::ne) { 943 assert((dom_bool->_test.is_less() && !proj->_con) || 944 (dom_bool->_test.is_greater() && proj->_con), "incorrect test"); 945 946 // this_bool = < 947 // dom_bool = >= (proj = True) or dom_bool = < (proj = False) 948 // x in [a, b[ on the fail (= True) projection, b > a-1 (because of hi_type->_lo > lo_type->_hi test above): 949 // lo = a, hi = b, adjusted_lim = b-a, cond = <u 950 // dom_bool = > (proj = True) or dom_bool = <= (proj = False) 951 // x in ]a, b[ on the fail (= True) projection, b > a: 952 // lo = a+1, hi = b, adjusted_lim = b-a-1, cond = <u 953 // this_bool = <= 954 // dom_bool = >= (proj = True) or dom_bool = < (proj = False) 955 // x in [a, b] on the fail (= True) projection, b+1 > a-1: 956 // lo = a, hi = b, adjusted_lim = b-a+1, cond = <u 957 // lo = a, hi = b, adjusted_lim = b-a, cond = <=u doesn't work because b = a - 1 is possible, then b-a = -1 958 // dom_bool = > (proj = True) or dom_bool = <= (proj = False) 959 // x in ]a, b] on the fail (= True) projection b+1 > a: 960 // lo = a+1, hi = b, adjusted_lim = b-a, cond = <u 961 // lo = a+1, hi = b, adjusted_lim = b-a-1, cond = <=u doesn't work because a = b is possible, then b-a-1 = -1 962 963 if (hi_test == BoolTest::lt) { 964 if (lo_test == BoolTest::gt || lo_test == BoolTest::le) { 965 lo = igvn->transform(new AddINode(lo, igvn->intcon(1))); 966 } 967 } else if (hi_test == BoolTest::le) { 968 if (lo_test == BoolTest::ge || lo_test == BoolTest::lt) { 969 adjusted_lim = igvn->transform(new SubINode(hi, lo)); 970 adjusted_lim = igvn->transform(new AddINode(adjusted_lim, igvn->intcon(1))); 971 cond = BoolTest::lt; 972 } else if (lo_test == BoolTest::gt || lo_test == BoolTest::le) { 973 adjusted_lim = igvn->transform(new SubINode(hi, lo)); 974 lo = igvn->transform(new AddINode(lo, igvn->intcon(1))); 975 cond = BoolTest::lt; 976 } else { 977 assert(false, "unhandled lo_test: %d", lo_test); 978 return false; 979 } 980 } else { 981 assert(igvn->_worklist.member(in(1)) && in(1)->Value(igvn) != igvn->type(in(1)), "unhandled hi_test: %d", hi_test); 982 return false; 983 } 984 // this test was canonicalized 985 assert(this_bool->_test.is_less() && fail->_con, "incorrect test"); 986 } else if (lo_type != nullptr && hi_type != nullptr && lo_type->_lo > hi_type->_hi && 987 lo_type->_hi == max_jint && hi_type->_lo == min_jint && lo_test != BoolTest::ne) { 988 989 // this_bool = < 990 // dom_bool = < (proj = True) or dom_bool = >= (proj = False) 991 // x in [b, a[ on the fail (= False) projection, a > b-1 (because of lo_type->_lo > hi_type->_hi above): 992 // lo = b, hi = a, adjusted_lim = a-b, cond = >=u 993 // dom_bool = <= (proj = True) or dom_bool = > (proj = False) 994 // x in [b, a] on the fail (= False) projection, a+1 > b-1: 995 // lo = b, hi = a, adjusted_lim = a-b+1, cond = >=u 996 // lo = b, hi = a, adjusted_lim = a-b, cond = >u doesn't work because a = b - 1 is possible, then b-a = -1 997 // this_bool = <= 998 // dom_bool = < (proj = True) or dom_bool = >= (proj = False) 999 // x in ]b, a[ on the fail (= False) projection, a > b: 1000 // lo = b+1, hi = a, adjusted_lim = a-b-1, cond = >=u 1001 // dom_bool = <= (proj = True) or dom_bool = > (proj = False) 1002 // x in ]b, a] on the fail (= False) projection, a+1 > b: 1003 // lo = b+1, hi = a, adjusted_lim = a-b, cond = >=u 1004 // lo = b+1, hi = a, adjusted_lim = a-b-1, cond = >u doesn't work because a = b is possible, then b-a-1 = -1 1005 1006 swap(lo, hi); 1007 swap(lo_type, hi_type); 1008 swap(lo_test, hi_test); 1009 1010 assert((dom_bool->_test.is_less() && proj->_con) || 1011 (dom_bool->_test.is_greater() && !proj->_con), "incorrect test"); 1012 1013 cond = (hi_test == BoolTest::le || hi_test == BoolTest::gt) ? BoolTest::gt : BoolTest::ge; 1014 1015 if (lo_test == BoolTest::lt) { 1016 if (hi_test == BoolTest::lt || hi_test == BoolTest::ge) { 1017 cond = BoolTest::ge; 1018 } else if (hi_test == BoolTest::le || hi_test == BoolTest::gt) { 1019 adjusted_lim = igvn->transform(new SubINode(hi, lo)); 1020 adjusted_lim = igvn->transform(new AddINode(adjusted_lim, igvn->intcon(1))); 1021 cond = BoolTest::ge; 1022 } else { 1023 assert(false, "unhandled hi_test: %d", hi_test); 1024 return false; 1025 } 1026 } else if (lo_test == BoolTest::le) { 1027 if (hi_test == BoolTest::lt || hi_test == BoolTest::ge) { 1028 lo = igvn->transform(new AddINode(lo, igvn->intcon(1))); 1029 cond = BoolTest::ge; 1030 } else if (hi_test == BoolTest::le || hi_test == BoolTest::gt) { 1031 adjusted_lim = igvn->transform(new SubINode(hi, lo)); 1032 lo = igvn->transform(new AddINode(lo, igvn->intcon(1))); 1033 cond = BoolTest::ge; 1034 } else { 1035 assert(false, "unhandled hi_test: %d", hi_test); 1036 return false; 1037 } 1038 } else { 1039 assert(igvn->_worklist.member(in(1)) && in(1)->Value(igvn) != igvn->type(in(1)), "unhandled lo_test: %d", lo_test); 1040 return false; 1041 } 1042 // this test was canonicalized 1043 assert(this_bool->_test.is_less() && !fail->_con, "incorrect test"); 1044 } else { 1045 const TypeInt* failtype = filtered_int_type(igvn, n, proj); 1046 if (failtype != nullptr) { 1047 const TypeInt* type2 = filtered_int_type(igvn, n, fail); 1048 if (type2 != nullptr) { 1049 failtype = failtype->join(type2)->is_int(); 1050 if (failtype->empty()) { 1051 // previous if determines the result of this if so 1052 // replace Bool with constant 1053 igvn->replace_input_of(this, 1, igvn->intcon(success->_con)); 1054 return true; 1055 } 1056 } 1057 } 1058 return false; 1059 } 1060 1061 assert(lo != nullptr && hi != nullptr, "sanity"); 1062 Node* hook = new Node(lo); // Add a use to lo to prevent him from dying 1063 // Merge the two compares into a single unsigned compare by building (CmpU (n - lo) (hi - lo)) 1064 Node* adjusted_val = igvn->transform(new SubINode(n, lo)); 1065 if (adjusted_lim == nullptr) { 1066 adjusted_lim = igvn->transform(new SubINode(hi, lo)); 1067 } 1068 hook->destruct(igvn); 1069 1070 if (adjusted_val->is_top() || adjusted_lim->is_top()) { 1071 return false; 1072 } 1073 1074 if (igvn->type(adjusted_lim)->is_int()->_lo < 0 && 1075 !igvn->C->post_loop_opts_phase()) { 1076 // If range check elimination applies to this comparison, it includes code to protect from overflows that may 1077 // cause the main loop to be skipped entirely. Delay this transformation. 1078 // Example: 1079 // for (int i = 0; i < limit; i++) { 1080 // if (i < max_jint && i > min_jint) {... 1081 // } 1082 // Comparisons folded as: 1083 // i - min_jint - 1 <u -2 1084 // when RC applies, main loop limit becomes: 1085 // min(limit, max(-2 + min_jint + 1, min_jint)) 1086 // = min(limit, min_jint) 1087 // = min_jint 1088 if (adjusted_val->outcnt() == 0) { 1089 igvn->remove_dead_node(adjusted_val); 1090 } 1091 if (adjusted_lim->outcnt() == 0) { 1092 igvn->remove_dead_node(adjusted_lim); 1093 } 1094 igvn->C->record_for_post_loop_opts_igvn(this); 1095 return false; 1096 } 1097 1098 Node* newcmp = igvn->transform(new CmpUNode(adjusted_val, adjusted_lim)); 1099 Node* newbool = igvn->transform(new BoolNode(newcmp, cond)); 1100 1101 igvn->replace_input_of(dom_iff, 1, igvn->intcon(proj->_con)); 1102 igvn->replace_input_of(this, 1, newbool); 1103 1104 return true; 1105 } 1106 1107 // Merge the branches that trap for this If and the dominating If into 1108 // a single region that branches to the uncommon trap for the 1109 // dominating If 1110 Node* IfNode::merge_uncommon_traps(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn) { 1111 Node* res = this; 1112 assert(success->in(0) == this, "bad projection"); 1113 1114 ProjNode* otherproj = proj->other_if_proj(); 1115 1116 CallStaticJavaNode* unc = success->is_uncommon_trap_proj(); 1117 CallStaticJavaNode* dom_unc = otherproj->is_uncommon_trap_proj(); 1118 1119 if (unc != dom_unc) { 1120 Node* r = new RegionNode(3); 1121 1122 r->set_req(1, otherproj); 1123 r->set_req(2, success); 1124 r = igvn->transform(r); 1125 assert(r->is_Region(), "can't go away"); 1126 1127 // Make both If trap at the state of the first If: once the CmpI 1128 // nodes are merged, if we trap we don't know which of the CmpI 1129 // nodes would have caused the trap so we have to restart 1130 // execution at the first one 1131 igvn->replace_input_of(dom_unc, 0, r); 1132 igvn->replace_input_of(unc, 0, igvn->C->top()); 1133 } 1134 int trap_request = dom_unc->uncommon_trap_request(); 1135 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(trap_request); 1136 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(trap_request); 1137 1138 int flip_test = 0; 1139 Node* l = nullptr; 1140 Node* r = nullptr; 1141 1142 if (success->in(0)->as_If()->range_check_trap_proj(flip_test, l, r) != nullptr) { 1143 // If this looks like a range check, change the trap to 1144 // Reason_range_check so the compiler recognizes it as a range 1145 // check and applies the corresponding optimizations 1146 trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_range_check, action); 1147 1148 improve_address_types(l, r, fail, igvn); 1149 1150 res = igvn->transform(new RangeCheckNode(in(0), in(1), _prob, _fcnt)); 1151 } else if (unc != dom_unc) { 1152 // If we trap we won't know what CmpI would have caused the trap 1153 // so use a special trap reason to mark this pair of CmpI nodes as 1154 // bad candidate for folding. On recompilation we won't fold them 1155 // and we may trap again but this time we'll know what branch 1156 // traps 1157 trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_unstable_fused_if, action); 1158 } 1159 igvn->replace_input_of(dom_unc, TypeFunc::Parms, igvn->intcon(trap_request)); 1160 return res; 1161 } 1162 1163 // If we are turning 2 CmpI nodes into a CmpU that follows the pattern 1164 // of a rangecheck on index i, on 64 bit the compares may be followed 1165 // by memory accesses using i as index. In that case, the CmpU tells 1166 // us something about the values taken by i that can help the compiler 1167 // (see Compile::conv_I2X_index()) 1168 void IfNode::improve_address_types(Node* l, Node* r, ProjNode* fail, PhaseIterGVN* igvn) { 1169 #ifdef _LP64 1170 ResourceMark rm; 1171 Node_Stack stack(2); 1172 1173 assert(r->Opcode() == Op_LoadRange, "unexpected range check"); 1174 const TypeInt* array_size = igvn->type(r)->is_int(); 1175 1176 stack.push(l, 0); 1177 1178 while(stack.size() > 0) { 1179 Node* n = stack.node(); 1180 uint start = stack.index(); 1181 1182 uint i = start; 1183 for (; i < n->outcnt(); i++) { 1184 Node* use = n->raw_out(i); 1185 if (stack.size() == 1) { 1186 if (use->Opcode() == Op_ConvI2L) { 1187 const TypeLong* bounds = use->as_Type()->type()->is_long(); 1188 if (bounds->_lo <= array_size->_lo && bounds->_hi >= array_size->_hi && 1189 (bounds->_lo != array_size->_lo || bounds->_hi != array_size->_hi)) { 1190 stack.set_index(i+1); 1191 stack.push(use, 0); 1192 break; 1193 } 1194 } 1195 } else if (use->is_Mem()) { 1196 Node* ctrl = use->in(0); 1197 for (int i = 0; i < 10 && ctrl != nullptr && ctrl != fail; i++) { 1198 ctrl = up_one_dom(ctrl); 1199 } 1200 if (ctrl == fail) { 1201 Node* init_n = stack.node_at(1); 1202 assert(init_n->Opcode() == Op_ConvI2L, "unexpected first node"); 1203 // Create a new narrow ConvI2L node that is dependent on the range check 1204 Node* new_n = igvn->C->conv_I2X_index(igvn, l, array_size, fail); 1205 1206 // The type of the ConvI2L may be widen and so the new 1207 // ConvI2L may not be better than an existing ConvI2L 1208 if (new_n != init_n) { 1209 for (uint j = 2; j < stack.size(); j++) { 1210 Node* n = stack.node_at(j); 1211 Node* clone = n->clone(); 1212 int rep = clone->replace_edge(init_n, new_n, igvn); 1213 assert(rep > 0, "can't find expected node?"); 1214 clone = igvn->transform(clone); 1215 init_n = n; 1216 new_n = clone; 1217 } 1218 igvn->hash_delete(use); 1219 int rep = use->replace_edge(init_n, new_n, igvn); 1220 assert(rep > 0, "can't find expected node?"); 1221 igvn->transform(use); 1222 if (init_n->outcnt() == 0) { 1223 igvn->_worklist.push(init_n); 1224 } 1225 } 1226 } 1227 } else if (use->in(0) == nullptr && (igvn->type(use)->isa_long() || 1228 igvn->type(use)->isa_ptr())) { 1229 stack.set_index(i+1); 1230 stack.push(use, 0); 1231 break; 1232 } 1233 } 1234 if (i == n->outcnt()) { 1235 stack.pop(); 1236 } 1237 } 1238 #endif 1239 } 1240 1241 bool IfNode::is_cmp_with_loadrange(ProjNode* proj) { 1242 if (in(1) != nullptr && 1243 in(1)->in(1) != nullptr && 1244 in(1)->in(1)->in(2) != nullptr) { 1245 Node* other = in(1)->in(1)->in(2); 1246 if (other->Opcode() == Op_LoadRange && 1247 ((other->in(0) != nullptr && other->in(0) == proj) || 1248 (other->in(0) == nullptr && 1249 other->in(2) != nullptr && 1250 other->in(2)->is_AddP() && 1251 other->in(2)->in(1) != nullptr && 1252 other->in(2)->in(1)->Opcode() == Op_CastPP && 1253 other->in(2)->in(1)->in(0) == proj))) { 1254 return true; 1255 } 1256 } 1257 return false; 1258 } 1259 1260 bool IfNode::is_null_check(ProjNode* proj, PhaseIterGVN* igvn) { 1261 Node* other = in(1)->in(1)->in(2); 1262 if (other->in(MemNode::Address) != nullptr && 1263 proj->in(0)->in(1) != nullptr && 1264 proj->in(0)->in(1)->is_Bool() && 1265 proj->in(0)->in(1)->in(1) != nullptr && 1266 proj->in(0)->in(1)->in(1)->Opcode() == Op_CmpP && 1267 proj->in(0)->in(1)->in(1)->in(2) != nullptr && 1268 proj->in(0)->in(1)->in(1)->in(1) == other->in(MemNode::Address)->in(AddPNode::Address)->uncast() && 1269 igvn->type(proj->in(0)->in(1)->in(1)->in(2)) == TypePtr::NULL_PTR) { 1270 return true; 1271 } 1272 return false; 1273 } 1274 1275 // Returns true if this IfNode belongs to a flat array check 1276 // and returns the corresponding array in the 'array' parameter. 1277 bool IfNode::is_flat_array_check(PhaseTransform* phase, Node** array) { 1278 Node* bol = in(1); 1279 if (!bol->is_Bool()) { 1280 return false; 1281 } 1282 Node* cmp = bol->in(1); 1283 if (cmp->isa_FlatArrayCheck()) { 1284 if (array != nullptr) { 1285 *array = cmp->in(FlatArrayCheckNode::ArrayOrKlass); 1286 } 1287 return true; 1288 } 1289 return false; 1290 } 1291 1292 // Check that the If that is in between the 2 integer comparisons has 1293 // no side effect 1294 bool IfNode::is_side_effect_free_test(ProjNode* proj, PhaseIterGVN* igvn) { 1295 if (proj == nullptr) { 1296 return false; 1297 } 1298 CallStaticJavaNode* unc = proj->is_uncommon_trap_if_pattern(); 1299 if (unc != nullptr && proj->outcnt() <= 2) { 1300 if (proj->outcnt() == 1 || 1301 // Allow simple null check from LoadRange 1302 (is_cmp_with_loadrange(proj) && is_null_check(proj, igvn))) { 1303 CallStaticJavaNode* unc = proj->is_uncommon_trap_if_pattern(); 1304 CallStaticJavaNode* dom_unc = proj->in(0)->in(0)->as_Proj()->is_uncommon_trap_if_pattern(); 1305 assert(dom_unc != nullptr, "is_uncommon_trap_if_pattern returned null"); 1306 1307 // reroute_side_effect_free_unc changes the state of this 1308 // uncommon trap to restart execution at the previous 1309 // CmpI. Check that this change in a previous compilation didn't 1310 // cause too many traps. 1311 int trap_request = unc->uncommon_trap_request(); 1312 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(trap_request); 1313 1314 if (igvn->C->too_many_traps(dom_unc->jvms()->method(), dom_unc->jvms()->bci(), reason)) { 1315 return false; 1316 } 1317 1318 if (!is_dominator_unc(dom_unc, unc)) { 1319 return false; 1320 } 1321 1322 return true; 1323 } 1324 } 1325 return false; 1326 } 1327 1328 // Make the If between the 2 integer comparisons trap at the state of 1329 // the first If: the last CmpI is the one replaced by a CmpU and the 1330 // first CmpI is eliminated, so the test between the 2 CmpI nodes 1331 // won't be guarded by the first CmpI anymore. It can trap in cases 1332 // where the first CmpI would have prevented it from executing: on a 1333 // trap, we need to restart execution at the state of the first CmpI 1334 void IfNode::reroute_side_effect_free_unc(ProjNode* proj, ProjNode* dom_proj, PhaseIterGVN* igvn) { 1335 CallStaticJavaNode* dom_unc = dom_proj->is_uncommon_trap_if_pattern(); 1336 ProjNode* otherproj = proj->other_if_proj(); 1337 CallStaticJavaNode* unc = proj->is_uncommon_trap_if_pattern(); 1338 Node* call_proj = dom_unc->unique_ctrl_out(); 1339 Node* halt = call_proj->unique_ctrl_out(); 1340 1341 Node* new_unc = dom_unc->clone(); 1342 call_proj = call_proj->clone(); 1343 halt = halt->clone(); 1344 Node* c = otherproj->clone(); 1345 1346 c = igvn->transform(c); 1347 new_unc->set_req(TypeFunc::Parms, unc->in(TypeFunc::Parms)); 1348 new_unc->set_req(0, c); 1349 new_unc = igvn->transform(new_unc); 1350 call_proj->set_req(0, new_unc); 1351 call_proj = igvn->transform(call_proj); 1352 halt->set_req(0, call_proj); 1353 halt = igvn->transform(halt); 1354 1355 igvn->replace_node(otherproj, igvn->C->top()); 1356 igvn->C->root()->add_req(halt); 1357 } 1358 1359 Node* IfNode::fold_compares(PhaseIterGVN* igvn) { 1360 if (Opcode() != Op_If) return nullptr; 1361 1362 if (cmpi_folds(igvn)) { 1363 Node* ctrl = in(0); 1364 if (is_ctrl_folds(ctrl, igvn)) { 1365 // A integer comparison immediately dominated by another integer 1366 // comparison 1367 ProjNode* success = nullptr; 1368 ProjNode* fail = nullptr; 1369 ProjNode* dom_cmp = ctrl->as_Proj(); 1370 if (has_shared_region(dom_cmp, success, fail) && 1371 // Next call modifies graph so must be last 1372 fold_compares_helper(dom_cmp, success, fail, igvn)) { 1373 return this; 1374 } 1375 if (has_only_uncommon_traps(dom_cmp, success, fail, igvn) && 1376 // Next call modifies graph so must be last 1377 fold_compares_helper(dom_cmp, success, fail, igvn)) { 1378 return merge_uncommon_traps(dom_cmp, success, fail, igvn); 1379 } 1380 return nullptr; 1381 } else if (ctrl->in(0) != nullptr && 1382 ctrl->in(0)->in(0) != nullptr) { 1383 ProjNode* success = nullptr; 1384 ProjNode* fail = nullptr; 1385 Node* dom = ctrl->in(0)->in(0); 1386 ProjNode* dom_cmp = dom->isa_Proj(); 1387 ProjNode* other_cmp = ctrl->isa_Proj(); 1388 1389 // Check if it's an integer comparison dominated by another 1390 // integer comparison with another test in between 1391 if (is_ctrl_folds(dom, igvn) && 1392 has_only_uncommon_traps(dom_cmp, success, fail, igvn) && 1393 is_side_effect_free_test(other_cmp, igvn) && 1394 // Next call modifies graph so must be last 1395 fold_compares_helper(dom_cmp, success, fail, igvn)) { 1396 reroute_side_effect_free_unc(other_cmp, dom_cmp, igvn); 1397 return merge_uncommon_traps(dom_cmp, success, fail, igvn); 1398 } 1399 } 1400 } 1401 return nullptr; 1402 } 1403 1404 //------------------------------remove_useless_bool---------------------------- 1405 // Check for people making a useless boolean: things like 1406 // if( (x < y ? true : false) ) { ... } 1407 // Replace with if( x < y ) { ... } 1408 static Node *remove_useless_bool(IfNode *iff, PhaseGVN *phase) { 1409 Node *i1 = iff->in(1); 1410 if( !i1->is_Bool() ) return nullptr; 1411 BoolNode *bol = i1->as_Bool(); 1412 1413 Node *cmp = bol->in(1); 1414 if( cmp->Opcode() != Op_CmpI ) return nullptr; 1415 1416 // Must be comparing against a bool 1417 const Type *cmp2_t = phase->type( cmp->in(2) ); 1418 if( cmp2_t != TypeInt::ZERO && 1419 cmp2_t != TypeInt::ONE ) 1420 return nullptr; 1421 1422 // Find a prior merge point merging the boolean 1423 i1 = cmp->in(1); 1424 if( !i1->is_Phi() ) return nullptr; 1425 PhiNode *phi = i1->as_Phi(); 1426 if( phase->type( phi ) != TypeInt::BOOL ) 1427 return nullptr; 1428 1429 // Check for diamond pattern 1430 int true_path = phi->is_diamond_phi(); 1431 if( true_path == 0 ) return nullptr; 1432 1433 // Make sure that iff and the control of the phi are different. This 1434 // should really only happen for dead control flow since it requires 1435 // an illegal cycle. 1436 if (phi->in(0)->in(1)->in(0) == iff) return nullptr; 1437 1438 // phi->region->if_proj->ifnode->bool->cmp 1439 BoolNode *bol2 = phi->in(0)->in(1)->in(0)->in(1)->as_Bool(); 1440 1441 // Now get the 'sense' of the test correct so we can plug in 1442 // either iff2->in(1) or its complement. 1443 int flip = 0; 1444 if( bol->_test._test == BoolTest::ne ) flip = 1-flip; 1445 else if( bol->_test._test != BoolTest::eq ) return nullptr; 1446 if( cmp2_t == TypeInt::ZERO ) flip = 1-flip; 1447 1448 const Type *phi1_t = phase->type( phi->in(1) ); 1449 const Type *phi2_t = phase->type( phi->in(2) ); 1450 // Check for Phi(0,1) and flip 1451 if( phi1_t == TypeInt::ZERO ) { 1452 if( phi2_t != TypeInt::ONE ) return nullptr; 1453 flip = 1-flip; 1454 } else { 1455 // Check for Phi(1,0) 1456 if( phi1_t != TypeInt::ONE ) return nullptr; 1457 if( phi2_t != TypeInt::ZERO ) return nullptr; 1458 } 1459 if( true_path == 2 ) { 1460 flip = 1-flip; 1461 } 1462 1463 Node* new_bol = (flip ? phase->transform( bol2->negate(phase) ) : bol2); 1464 assert(new_bol != iff->in(1), "must make progress"); 1465 iff->set_req_X(1, new_bol, phase); 1466 // Intervening diamond probably goes dead 1467 phase->C->set_major_progress(); 1468 return iff; 1469 } 1470 1471 static IfNode* idealize_test(PhaseGVN* phase, IfNode* iff); 1472 1473 struct RangeCheck { 1474 IfProjNode* ctl; 1475 jint off; 1476 }; 1477 1478 Node* IfNode::Ideal_common(PhaseGVN *phase, bool can_reshape) { 1479 if (remove_dead_region(phase, can_reshape)) return this; 1480 // No Def-Use info? 1481 if (!can_reshape) return nullptr; 1482 1483 // Don't bother trying to transform a dead if 1484 if (in(0)->is_top()) return nullptr; 1485 // Don't bother trying to transform an if with a dead test 1486 if (in(1)->is_top()) return nullptr; 1487 // Another variation of a dead test 1488 if (in(1)->is_Con()) return nullptr; 1489 // Another variation of a dead if 1490 if (outcnt() < 2) return nullptr; 1491 1492 // Canonicalize the test. 1493 Node* idt_if = idealize_test(phase, this); 1494 if (idt_if != nullptr) return idt_if; 1495 1496 // Try to split the IF 1497 PhaseIterGVN *igvn = phase->is_IterGVN(); 1498 Node *s = split_if(this, igvn); 1499 if (s != nullptr) return s; 1500 1501 return NodeSentinel; 1502 } 1503 1504 //------------------------------Ideal------------------------------------------ 1505 // Return a node which is more "ideal" than the current node. Strip out 1506 // control copies 1507 Node* IfNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1508 Node* res = Ideal_common(phase, can_reshape); 1509 if (res != NodeSentinel) { 1510 return res; 1511 } 1512 1513 // Check for people making a useless boolean: things like 1514 // if( (x < y ? true : false) ) { ... } 1515 // Replace with if( x < y ) { ... } 1516 Node* bol2 = remove_useless_bool(this, phase); 1517 if (bol2) return bol2; 1518 1519 if (in(0) == nullptr) return nullptr; // Dead loop? 1520 1521 PhaseIterGVN* igvn = phase->is_IterGVN(); 1522 Node* result = fold_compares(igvn); 1523 if (result != nullptr) { 1524 return result; 1525 } 1526 1527 // Scan for an equivalent test 1528 int dist = 4; // Cutoff limit for search 1529 if (is_If() && in(1)->is_Bool()) { 1530 Node* cmp = in(1)->in(1); 1531 if (cmp->Opcode() == Op_CmpP && 1532 cmp->in(2) != nullptr && // make sure cmp is not already dead 1533 cmp->in(2)->bottom_type() == TypePtr::NULL_PTR) { 1534 dist = 64; // Limit for null-pointer scans 1535 } 1536 } 1537 1538 Node* prev_dom = search_identical(dist, igvn); 1539 1540 if (prev_dom != nullptr) { 1541 // Dominating CountedLoopEnd (left over from some now dead loop) will become the new loop exit. Outer strip mined 1542 // loop will go away. Mark this loop as no longer strip mined. 1543 if (is_CountedLoopEnd()) { 1544 CountedLoopNode* counted_loop_node = as_CountedLoopEnd()->loopnode(); 1545 if (counted_loop_node != nullptr) { 1546 counted_loop_node->clear_strip_mined(); 1547 } 1548 } 1549 // Replace dominated IfNode 1550 return dominated_by(prev_dom, igvn, false); 1551 } 1552 1553 return simple_subsuming(igvn); 1554 } 1555 1556 //------------------------------dominated_by----------------------------------- 1557 Node* IfNode::dominated_by(Node* prev_dom, PhaseIterGVN* igvn, bool pin_array_access_nodes) { 1558 #ifndef PRODUCT 1559 if (TraceIterativeGVN) { 1560 tty->print(" Removing IfNode: "); this->dump(); 1561 } 1562 #endif 1563 1564 igvn->hash_delete(this); // Remove self to prevent spurious V-N 1565 Node *idom = in(0); 1566 // Need opcode to decide which way 'this' test goes 1567 int prev_op = prev_dom->Opcode(); 1568 Node *top = igvn->C->top(); // Shortcut to top 1569 1570 // Now walk the current IfNode's projections. 1571 // Loop ends when 'this' has no more uses. 1572 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) { 1573 Node *ifp = last_out(i); // Get IfTrue/IfFalse 1574 igvn->add_users_to_worklist(ifp); 1575 // Check which projection it is and set target. 1576 // Data-target is either the dominating projection of the same type 1577 // or TOP if the dominating projection is of opposite type. 1578 // Data-target will be used as the new control edge for the non-CFG 1579 // nodes like Casts and Loads. 1580 Node *data_target = (ifp->Opcode() == prev_op) ? prev_dom : top; 1581 // Control-target is just the If's immediate dominator or TOP. 1582 Node *ctrl_target = (ifp->Opcode() == prev_op) ? idom : top; 1583 1584 // For each child of an IfTrue/IfFalse projection, reroute. 1585 // Loop ends when projection has no more uses. 1586 for (DUIterator_Last jmin, j = ifp->last_outs(jmin); j >= jmin; --j) { 1587 Node* s = ifp->last_out(j); // Get child of IfTrue/IfFalse 1588 if (s->depends_only_on_test() && igvn->no_dependent_zero_check(s)) { 1589 // For control producers. 1590 // Do not rewire Div and Mod nodes which could have a zero divisor to avoid skipping their zero check. 1591 igvn->replace_input_of(s, 0, data_target); // Move child to data-target 1592 if (pin_array_access_nodes && data_target != top) { 1593 // As a result of range check smearing, Loads and range check Cast nodes that are control dependent on this 1594 // range check (that is about to be removed) now depend on multiple dominating range checks. After the removal 1595 // of this range check, these control dependent nodes end up at the lowest/nearest dominating check in the 1596 // graph. To ensure that these Loads/Casts do not float above any of the dominating checks (even when the 1597 // lowest dominating check is later replaced by yet another dominating check), we need to pin them at the 1598 // lowest dominating check. 1599 Node* clone = s->pin_array_access_node(); 1600 if (clone != nullptr) { 1601 clone = igvn->transform(clone); 1602 igvn->replace_node(s, clone); 1603 } 1604 } 1605 } else { 1606 // Find the control input matching this def-use edge. 1607 // For Regions it may not be in slot 0. 1608 uint l; 1609 for (l = 0; s->in(l) != ifp; l++) { } 1610 igvn->replace_input_of(s, l, ctrl_target); 1611 } 1612 } // End for each child of a projection 1613 1614 igvn->remove_dead_node(ifp); 1615 } // End for each IfTrue/IfFalse child of If 1616 1617 // Kill the IfNode 1618 igvn->remove_dead_node(this); 1619 1620 // Must return either the original node (now dead) or a new node 1621 // (Do not return a top here, since that would break the uniqueness of top.) 1622 return new ConINode(TypeInt::ZERO); 1623 } 1624 1625 Node* IfNode::search_identical(int dist, PhaseIterGVN* igvn) { 1626 // Setup to scan up the CFG looking for a dominating test 1627 Node* dom = in(0); 1628 Node* prev_dom = this; 1629 int op = Opcode(); 1630 // Search up the dominator tree for an If with an identical test 1631 while (dom->Opcode() != op || // Not same opcode? 1632 !same_condition(dom, igvn) || // Not same input 1? 1633 prev_dom->in(0) != dom) { // One path of test does not dominate? 1634 if (dist < 0) return nullptr; 1635 1636 dist--; 1637 prev_dom = dom; 1638 dom = up_one_dom(dom); 1639 if (!dom) return nullptr; 1640 } 1641 1642 // Check that we did not follow a loop back to ourselves 1643 if (this == dom) { 1644 return nullptr; 1645 } 1646 1647 #ifndef PRODUCT 1648 if (dist > 2) { // Add to count of null checks elided 1649 explicit_null_checks_elided++; 1650 } 1651 #endif 1652 1653 return prev_dom; 1654 } 1655 1656 bool IfNode::same_condition(const Node* dom, PhaseIterGVN* igvn) const { 1657 Node* dom_bool = dom->in(1); 1658 Node* this_bool = in(1); 1659 if (dom_bool == this_bool) { 1660 return true; 1661 } 1662 1663 if (dom_bool == nullptr || !dom_bool->is_Bool() || 1664 this_bool == nullptr || !this_bool->is_Bool()) { 1665 return false; 1666 } 1667 Node* dom_cmp = dom_bool->in(1); 1668 Node* this_cmp = this_bool->in(1); 1669 1670 // If the comparison is a subtype check, then SubTypeCheck nodes may have profile data attached to them and may be 1671 // different nodes even-though they perform the same subtype check 1672 if (dom_cmp == nullptr || !dom_cmp->is_SubTypeCheck() || 1673 this_cmp == nullptr || !this_cmp->is_SubTypeCheck()) { 1674 return false; 1675 } 1676 1677 if (dom_cmp->in(1) != this_cmp->in(1) || 1678 dom_cmp->in(2) != this_cmp->in(2) || 1679 dom_bool->as_Bool()->_test._test != this_bool->as_Bool()->_test._test) { 1680 return false; 1681 } 1682 1683 return true; 1684 } 1685 1686 1687 static int subsuming_bool_test_encode(Node*); 1688 1689 // Check if dominating test is subsuming 'this' one. 1690 // 1691 // cmp 1692 // / \ 1693 // (r1) bool \ 1694 // / bool (r2) 1695 // (dom) if \ 1696 // \ ) 1697 // (pre) if[TF] / 1698 // \ / 1699 // if (this) 1700 // \r1 1701 // r2\ eqT eqF neT neF ltT ltF leT leF gtT gtF geT geF 1702 // eq t f f t f - - f f - - f 1703 // ne f t t f t - - t t - - t 1704 // lt f - - f t f - f f - f t 1705 // le t - - t t - t f f t - t 1706 // gt f - - f f - f t t f - f 1707 // ge t - - t f t - t t - t f 1708 // 1709 Node* IfNode::simple_subsuming(PhaseIterGVN* igvn) { 1710 // Table encoding: N/A (na), True-branch (tb), False-branch (fb). 1711 static enum { na, tb, fb } s_short_circuit_map[6][12] = { 1712 /*rel: eq+T eq+F ne+T ne+F lt+T lt+F le+T le+F gt+T gt+F ge+T ge+F*/ 1713 /*eq*/{ tb, fb, fb, tb, fb, na, na, fb, fb, na, na, fb }, 1714 /*ne*/{ fb, tb, tb, fb, tb, na, na, tb, tb, na, na, tb }, 1715 /*lt*/{ fb, na, na, fb, tb, fb, na, fb, fb, na, fb, tb }, 1716 /*le*/{ tb, na, na, tb, tb, na, tb, fb, fb, tb, na, tb }, 1717 /*gt*/{ fb, na, na, fb, fb, na, fb, tb, tb, fb, na, fb }, 1718 /*ge*/{ tb, na, na, tb, fb, tb, na, tb, tb, na, tb, fb }}; 1719 1720 Node* pre = in(0); 1721 if (!pre->is_IfTrue() && !pre->is_IfFalse()) { 1722 return nullptr; 1723 } 1724 Node* dom = pre->in(0); 1725 if (!dom->is_If()) { 1726 return nullptr; 1727 } 1728 Node* bol = in(1); 1729 if (!bol->is_Bool()) { 1730 return nullptr; 1731 } 1732 Node* cmp = in(1)->in(1); 1733 if (!cmp->is_Cmp()) { 1734 return nullptr; 1735 } 1736 1737 if (!dom->in(1)->is_Bool()) { 1738 return nullptr; 1739 } 1740 if (dom->in(1)->in(1) != cmp) { // Not same cond? 1741 return nullptr; 1742 } 1743 1744 int drel = subsuming_bool_test_encode(dom->in(1)); 1745 int trel = subsuming_bool_test_encode(bol); 1746 int bout = pre->is_IfFalse() ? 1 : 0; 1747 1748 if (drel < 0 || trel < 0) { 1749 return nullptr; 1750 } 1751 int br = s_short_circuit_map[trel][2*drel+bout]; 1752 if (br == na) { 1753 return nullptr; 1754 } 1755 #ifndef PRODUCT 1756 if (TraceIterativeGVN) { 1757 tty->print(" Subsumed IfNode: "); dump(); 1758 } 1759 #endif 1760 // Replace condition with constant True(1)/False(0). 1761 bool is_always_true = br == tb; 1762 set_req(1, igvn->intcon(is_always_true ? 1 : 0)); 1763 1764 // Update any data dependencies to the directly dominating test. This subsumed test is not immediately removed by igvn 1765 // and therefore subsequent optimizations might miss these data dependencies otherwise. There might be a dead loop 1766 // ('always_taken_proj' == 'pre') that is cleaned up later. Skip this case to make the iterator work properly. 1767 Node* always_taken_proj = proj_out(is_always_true); 1768 if (always_taken_proj != pre) { 1769 for (DUIterator_Fast imax, i = always_taken_proj->fast_outs(imax); i < imax; i++) { 1770 Node* u = always_taken_proj->fast_out(i); 1771 if (!u->is_CFG()) { 1772 igvn->replace_input_of(u, 0, pre); 1773 --i; 1774 --imax; 1775 } 1776 } 1777 } 1778 1779 if (bol->outcnt() == 0) { 1780 igvn->remove_dead_node(bol); // Kill the BoolNode. 1781 } 1782 return this; 1783 } 1784 1785 // Map BoolTest to local table encoding. The BoolTest (e)numerals 1786 // { eq = 0, ne = 4, le = 5, ge = 7, lt = 3, gt = 1 } 1787 // are mapped to table indices, while the remaining (e)numerals in BoolTest 1788 // { overflow = 2, no_overflow = 6, never = 8, illegal = 9 } 1789 // are ignored (these are not modeled in the table). 1790 // 1791 static int subsuming_bool_test_encode(Node* node) { 1792 precond(node->is_Bool()); 1793 BoolTest::mask x = node->as_Bool()->_test._test; 1794 switch (x) { 1795 case BoolTest::eq: return 0; 1796 case BoolTest::ne: return 1; 1797 case BoolTest::lt: return 2; 1798 case BoolTest::le: return 3; 1799 case BoolTest::gt: return 4; 1800 case BoolTest::ge: return 5; 1801 case BoolTest::overflow: 1802 case BoolTest::no_overflow: 1803 case BoolTest::never: 1804 case BoolTest::illegal: 1805 default: 1806 return -1; 1807 } 1808 } 1809 1810 //------------------------------Identity--------------------------------------- 1811 // If the test is constant & we match, then we are the input Control 1812 Node* IfProjNode::Identity(PhaseGVN* phase) { 1813 // Can only optimize if cannot go the other way 1814 const TypeTuple *t = phase->type(in(0))->is_tuple(); 1815 if (t == TypeTuple::IFNEITHER || (always_taken(t) && 1816 // During parsing (GVN) we don't remove dead code aggressively. 1817 // Cut off dead branch and let PhaseRemoveUseless take care of it. 1818 (!phase->is_IterGVN() || 1819 // During IGVN, first wait for the dead branch to be killed. 1820 // Otherwise, the IfNode's control will have two control uses (the IfNode 1821 // that doesn't go away because it still has uses and this branch of the 1822 // If) which breaks other optimizations. Node::has_special_unique_user() 1823 // will cause this node to be reprocessed once the dead branch is killed. 1824 in(0)->outcnt() == 1))) { 1825 // IfNode control 1826 if (in(0)->is_BaseCountedLoopEnd()) { 1827 // CountedLoopEndNode may be eliminated by if subsuming, replace CountedLoopNode with LoopNode to 1828 // avoid mismatching between CountedLoopNode and CountedLoopEndNode in the following optimization. 1829 Node* head = unique_ctrl_out_or_null(); 1830 if (head != nullptr && head->is_BaseCountedLoop() && head->in(LoopNode::LoopBackControl) == this) { 1831 Node* new_head = new LoopNode(head->in(LoopNode::EntryControl), this); 1832 phase->is_IterGVN()->register_new_node_with_optimizer(new_head); 1833 phase->is_IterGVN()->replace_node(head, new_head); 1834 } 1835 } 1836 return in(0)->in(0); 1837 } 1838 // no progress 1839 return this; 1840 } 1841 1842 bool IfNode::is_zero_trip_guard() const { 1843 if (in(1)->is_Bool() && in(1)->in(1)->is_Cmp()) { 1844 return in(1)->in(1)->in(1)->Opcode() == Op_OpaqueZeroTripGuard; 1845 } 1846 return false; 1847 } 1848 1849 void IfProjNode::pin_array_access_nodes(PhaseIterGVN* igvn) { 1850 for (DUIterator i = outs(); has_out(i); i++) { 1851 Node* u = out(i); 1852 if (!u->depends_only_on_test()) { 1853 continue; 1854 } 1855 Node* clone = u->pin_array_access_node(); 1856 if (clone != nullptr) { 1857 clone = igvn->transform(clone); 1858 assert(clone != u, "shouldn't common"); 1859 igvn->replace_node(u, clone); 1860 --i; 1861 } 1862 } 1863 } 1864 1865 #ifndef PRODUCT 1866 void IfNode::dump_spec(outputStream* st) const { 1867 switch (_assertion_predicate_type) { 1868 case AssertionPredicateType::InitValue: 1869 st->print("#Init Value Assertion Predicate "); 1870 break; 1871 case AssertionPredicateType::LastValue: 1872 st->print("#Last Value Assertion Predicate "); 1873 break; 1874 case AssertionPredicateType::FinalIv: 1875 st->print("#Final IV Assertion Predicate "); 1876 break; 1877 case AssertionPredicateType::None: 1878 // No Assertion Predicate 1879 break; 1880 default: 1881 fatal("Unknown Assertion Predicate type"); 1882 } 1883 st->print("P=%f, C=%f", _prob, _fcnt); 1884 } 1885 #endif // NOT PRODUCT 1886 1887 //------------------------------idealize_test---------------------------------- 1888 // Try to canonicalize tests better. Peek at the Cmp/Bool/If sequence and 1889 // come up with a canonical sequence. Bools getting 'eq', 'gt' and 'ge' forms 1890 // converted to 'ne', 'le' and 'lt' forms. IfTrue/IfFalse get swapped as 1891 // needed. 1892 static IfNode* idealize_test(PhaseGVN* phase, IfNode* iff) { 1893 assert(iff->in(0) != nullptr, "If must be live"); 1894 1895 if (iff->outcnt() != 2) return nullptr; // Malformed projections. 1896 Node* old_if_f = iff->proj_out(false); 1897 Node* old_if_t = iff->proj_out(true); 1898 1899 // CountedLoopEnds want the back-control test to be TRUE, regardless of 1900 // whether they are testing a 'gt' or 'lt' condition. The 'gt' condition 1901 // happens in count-down loops 1902 if (iff->is_BaseCountedLoopEnd()) return nullptr; 1903 if (!iff->in(1)->is_Bool()) return nullptr; // Happens for partially optimized IF tests 1904 BoolNode *b = iff->in(1)->as_Bool(); 1905 BoolTest bt = b->_test; 1906 // Test already in good order? 1907 if( bt.is_canonical() ) 1908 return nullptr; 1909 1910 // Flip test to be canonical. Requires flipping the IfFalse/IfTrue and 1911 // cloning the IfNode. 1912 Node* new_b = phase->transform( new BoolNode(b->in(1), bt.negate()) ); 1913 if( !new_b->is_Bool() ) return nullptr; 1914 b = new_b->as_Bool(); 1915 1916 PhaseIterGVN *igvn = phase->is_IterGVN(); 1917 assert( igvn, "Test is not canonical in parser?" ); 1918 1919 // The IF node never really changes, but it needs to be cloned 1920 iff = iff->clone()->as_If(); 1921 iff->set_req(1, b); 1922 iff->_prob = 1.0-iff->_prob; 1923 1924 Node *prior = igvn->hash_find_insert(iff); 1925 if( prior ) { 1926 igvn->remove_dead_node(iff); 1927 iff = (IfNode*)prior; 1928 } else { 1929 // Cannot call transform on it just yet 1930 igvn->set_type_bottom(iff); 1931 } 1932 igvn->_worklist.push(iff); 1933 1934 // Now handle projections. Cloning not required. 1935 Node* new_if_f = (Node*)(new IfFalseNode( iff )); 1936 Node* new_if_t = (Node*)(new IfTrueNode ( iff )); 1937 1938 igvn->register_new_node_with_optimizer(new_if_f); 1939 igvn->register_new_node_with_optimizer(new_if_t); 1940 // Flip test, so flip trailing control 1941 igvn->replace_node(old_if_f, new_if_t); 1942 igvn->replace_node(old_if_t, new_if_f); 1943 1944 // Progress 1945 return iff; 1946 } 1947 1948 Node* RangeCheckNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1949 Node* res = Ideal_common(phase, can_reshape); 1950 if (res != NodeSentinel) { 1951 return res; 1952 } 1953 1954 PhaseIterGVN *igvn = phase->is_IterGVN(); 1955 // Setup to scan up the CFG looking for a dominating test 1956 Node* prev_dom = this; 1957 1958 // Check for range-check vs other kinds of tests 1959 Node* index1; 1960 Node* range1; 1961 jint offset1; 1962 int flip1 = is_range_check(range1, index1, offset1); 1963 if (flip1) { 1964 Node* dom = in(0); 1965 // Try to remove extra range checks. All 'up_one_dom' gives up at merges 1966 // so all checks we inspect post-dominate the top-most check we find. 1967 // If we are going to fail the current check and we reach the top check 1968 // then we are guaranteed to fail, so just start interpreting there. 1969 // We 'expand' the top 3 range checks to include all post-dominating 1970 // checks. 1971 // 1972 // Example: 1973 // a[i+x] // (1) 1 < x < 6 1974 // a[i+3] // (2) 1975 // a[i+4] // (3) 1976 // a[i+6] // max = max of all constants 1977 // a[i+2] 1978 // a[i+1] // min = min of all constants 1979 // 1980 // If x < 3: 1981 // (1) a[i+x]: Leave unchanged 1982 // (2) a[i+3]: Replace with a[i+max] = a[i+6]: i+x < i+3 <= i+6 -> (2) is covered 1983 // (3) a[i+4]: Replace with a[i+min] = a[i+1]: i+1 < i+4 <= i+6 -> (3) and all following checks are covered 1984 // Remove all other a[i+c] checks 1985 // 1986 // If x >= 3: 1987 // (1) a[i+x]: Leave unchanged 1988 // (2) a[i+3]: Replace with a[i+min] = a[i+1]: i+1 < i+3 <= i+x -> (2) is covered 1989 // (3) a[i+4]: Replace with a[i+max] = a[i+6]: i+1 < i+4 <= i+6 -> (3) and all following checks are covered 1990 // Remove all other a[i+c] checks 1991 // 1992 // We only need the top 2 range checks if x is the min or max of all constants. 1993 // 1994 // This, however, only works if the interval [i+min,i+max] is not larger than max_int (i.e. abs(max - min) < max_int): 1995 // The theoretical max size of an array is max_int with: 1996 // - Valid index space: [0,max_int-1] 1997 // - Invalid index space: [max_int,-1] // max_int, min_int, min_int - 1 ..., -1 1998 // 1999 // The size of the consecutive valid index space is smaller than the size of the consecutive invalid index space. 2000 // If we choose min and max in such a way that: 2001 // - abs(max - min) < max_int 2002 // - i+max and i+min are inside the valid index space 2003 // then all indices [i+min,i+max] must be in the valid index space. Otherwise, the invalid index space must be 2004 // smaller than the valid index space which is never the case for any array size. 2005 // 2006 // Choosing a smaller array size only makes the valid index space smaller and the invalid index space larger and 2007 // the argument above still holds. 2008 // 2009 // Note that the same optimization with the same maximal accepted interval size can also be found in C1. 2010 const jlong maximum_number_of_min_max_interval_indices = (jlong)max_jint; 2011 2012 // The top 3 range checks seen 2013 const int NRC = 3; 2014 RangeCheck prev_checks[NRC]; 2015 int nb_checks = 0; 2016 2017 // Low and high offsets seen so far 2018 jint off_lo = offset1; 2019 jint off_hi = offset1; 2020 2021 bool found_immediate_dominator = false; 2022 2023 // Scan for the top checks and collect range of offsets 2024 for (int dist = 0; dist < 999; dist++) { // Range-Check scan limit 2025 if (dom->Opcode() == Op_RangeCheck && // Not same opcode? 2026 prev_dom->in(0) == dom) { // One path of test does dominate? 2027 if (dom == this) return nullptr; // dead loop 2028 // See if this is a range check 2029 Node* index2; 2030 Node* range2; 2031 jint offset2; 2032 int flip2 = dom->as_RangeCheck()->is_range_check(range2, index2, offset2); 2033 // See if this is a _matching_ range check, checking against 2034 // the same array bounds. 2035 if (flip2 == flip1 && range2 == range1 && index2 == index1 && 2036 dom->outcnt() == 2) { 2037 if (nb_checks == 0 && dom->in(1) == in(1)) { 2038 // Found an immediately dominating test at the same offset. 2039 // This kind of back-to-back test can be eliminated locally, 2040 // and there is no need to search further for dominating tests. 2041 assert(offset2 == offset1, "Same test but different offsets"); 2042 found_immediate_dominator = true; 2043 break; 2044 } 2045 2046 // "x - y" -> must add one to the difference for number of elements in [x,y] 2047 const jlong diff = (jlong)MIN2(offset2, off_lo) - (jlong)MAX2(offset2, off_hi); 2048 if (ABS(diff) < maximum_number_of_min_max_interval_indices) { 2049 // Gather expanded bounds 2050 off_lo = MIN2(off_lo, offset2); 2051 off_hi = MAX2(off_hi, offset2); 2052 // Record top NRC range checks 2053 prev_checks[nb_checks % NRC].ctl = prev_dom->as_IfProj(); 2054 prev_checks[nb_checks % NRC].off = offset2; 2055 nb_checks++; 2056 } 2057 } 2058 } 2059 prev_dom = dom; 2060 dom = up_one_dom(dom); 2061 if (!dom) break; 2062 } 2063 2064 if (!found_immediate_dominator) { 2065 // Attempt to widen the dominating range check to cover some later 2066 // ones. Since range checks "fail" by uncommon-trapping to the 2067 // interpreter, widening a check can make us speculatively enter 2068 // the interpreter. If we see range-check deopt's, do not widen! 2069 if (!phase->C->allow_range_check_smearing()) return nullptr; 2070 2071 if (can_reshape && !phase->C->post_loop_opts_phase()) { 2072 // We are about to perform range check smearing (i.e. remove this RangeCheck if it is dominated by 2073 // a series of RangeChecks which have a range that covers this RangeCheck). This can cause array access nodes to 2074 // be pinned. We want to avoid that and first allow range check elimination a chance to remove the RangeChecks 2075 // from loops. Hence, we delay range check smearing until after loop opts. 2076 phase->C->record_for_post_loop_opts_igvn(this); 2077 return nullptr; 2078 } 2079 2080 // Didn't find prior covering check, so cannot remove anything. 2081 if (nb_checks == 0) { 2082 return nullptr; 2083 } 2084 // Constant indices only need to check the upper bound. 2085 // Non-constant indices must check both low and high. 2086 int chk0 = (nb_checks - 1) % NRC; 2087 if (index1) { 2088 if (nb_checks == 1) { 2089 return nullptr; 2090 } else { 2091 // If the top range check's constant is the min or max of 2092 // all constants we widen the next one to cover the whole 2093 // range of constants. 2094 RangeCheck rc0 = prev_checks[chk0]; 2095 int chk1 = (nb_checks - 2) % NRC; 2096 RangeCheck rc1 = prev_checks[chk1]; 2097 if (rc0.off == off_lo) { 2098 adjust_check(rc1.ctl, range1, index1, flip1, off_hi, igvn); 2099 prev_dom = rc1.ctl; 2100 } else if (rc0.off == off_hi) { 2101 adjust_check(rc1.ctl, range1, index1, flip1, off_lo, igvn); 2102 prev_dom = rc1.ctl; 2103 } else { 2104 // If the top test's constant is not the min or max of all 2105 // constants, we need 3 range checks. We must leave the 2106 // top test unchanged because widening it would allow the 2107 // accesses it protects to successfully read/write out of 2108 // bounds. 2109 if (nb_checks == 2) { 2110 return nullptr; 2111 } 2112 int chk2 = (nb_checks - 3) % NRC; 2113 RangeCheck rc2 = prev_checks[chk2]; 2114 // The top range check a+i covers interval: -a <= i < length-a 2115 // The second range check b+i covers interval: -b <= i < length-b 2116 if (rc1.off <= rc0.off) { 2117 // if b <= a, we change the second range check to: 2118 // -min_of_all_constants <= i < length-min_of_all_constants 2119 // Together top and second range checks now cover: 2120 // -min_of_all_constants <= i < length-a 2121 // which is more restrictive than -b <= i < length-b: 2122 // -b <= -min_of_all_constants <= i < length-a <= length-b 2123 // The third check is then changed to: 2124 // -max_of_all_constants <= i < length-max_of_all_constants 2125 // so 2nd and 3rd checks restrict allowed values of i to: 2126 // -min_of_all_constants <= i < length-max_of_all_constants 2127 adjust_check(rc1.ctl, range1, index1, flip1, off_lo, igvn); 2128 adjust_check(rc2.ctl, range1, index1, flip1, off_hi, igvn); 2129 } else { 2130 // if b > a, we change the second range check to: 2131 // -max_of_all_constants <= i < length-max_of_all_constants 2132 // Together top and second range checks now cover: 2133 // -a <= i < length-max_of_all_constants 2134 // which is more restrictive than -b <= i < length-b: 2135 // -b < -a <= i < length-max_of_all_constants <= length-b 2136 // The third check is then changed to: 2137 // -max_of_all_constants <= i < length-max_of_all_constants 2138 // so 2nd and 3rd checks restrict allowed values of i to: 2139 // -min_of_all_constants <= i < length-max_of_all_constants 2140 adjust_check(rc1.ctl, range1, index1, flip1, off_hi, igvn); 2141 adjust_check(rc2.ctl, range1, index1, flip1, off_lo, igvn); 2142 } 2143 prev_dom = rc2.ctl; 2144 } 2145 } 2146 } else { 2147 RangeCheck rc0 = prev_checks[chk0]; 2148 // 'Widen' the offset of the 1st and only covering check 2149 adjust_check(rc0.ctl, range1, index1, flip1, off_hi, igvn); 2150 // Test is now covered by prior checks, dominate it out 2151 prev_dom = rc0.ctl; 2152 } 2153 // The last RangeCheck is found to be redundant with a sequence of n (n >= 2) preceding RangeChecks. 2154 // If an array load is control dependent on the eliminated range check, the array load nodes (CastII and Load) 2155 // become control dependent on the last range check of the sequence, but they are really dependent on the entire 2156 // sequence of RangeChecks. If RangeCheck#n is later replaced by a dominating identical check, the array load 2157 // nodes must not float above the n-1 other RangeCheck in the sequence. We pin the array load nodes here to 2158 // guarantee it doesn't happen. 2159 // 2160 // RangeCheck#1 RangeCheck#1 2161 // | \ | \ 2162 // | uncommon trap | uncommon trap 2163 // .. .. 2164 // RangeCheck#n -> RangeCheck#n 2165 // | \ | \ 2166 // | uncommon trap CastII uncommon trap 2167 // RangeCheck Load 2168 // | \ 2169 // CastII uncommon trap 2170 // Load 2171 2172 return dominated_by(prev_dom, igvn, true); 2173 } 2174 } else { 2175 prev_dom = search_identical(4, igvn); 2176 2177 if (prev_dom == nullptr) { 2178 return nullptr; 2179 } 2180 } 2181 2182 // Replace dominated IfNode 2183 return dominated_by(prev_dom, igvn, false); 2184 } 2185 2186 ParsePredicateNode::ParsePredicateNode(Node* control, Deoptimization::DeoptReason deopt_reason, PhaseGVN* gvn) 2187 : IfNode(control, gvn->intcon(1), PROB_MAX, COUNT_UNKNOWN), 2188 _deopt_reason(deopt_reason), 2189 _useless(false) { 2190 init_class_id(Class_ParsePredicate); 2191 gvn->C->add_parse_predicate(this); 2192 gvn->C->record_for_post_loop_opts_igvn(this); 2193 #ifdef ASSERT 2194 switch (deopt_reason) { 2195 case Deoptimization::Reason_predicate: 2196 case Deoptimization::Reason_profile_predicate: 2197 case Deoptimization::Reason_loop_limit_check: 2198 break; 2199 default: 2200 assert(false, "unsupported deoptimization reason for Parse Predicate"); 2201 } 2202 #endif // ASSERT 2203 } 2204 2205 Node* ParsePredicateNode::uncommon_trap() const { 2206 ParsePredicateUncommonProj* uncommon_proj = proj_out(0)->as_IfFalse(); 2207 Node* uct_region_or_call = uncommon_proj->unique_ctrl_out(); 2208 assert(uct_region_or_call->is_Region() || uct_region_or_call->is_Call(), "must be a region or call uct"); 2209 return uct_region_or_call; 2210 } 2211 2212 // Fold this node away once it becomes useless or at latest in post loop opts IGVN. 2213 const Type* ParsePredicateNode::Value(PhaseGVN* phase) const { 2214 if (phase->type(in(0)) == Type::TOP) { 2215 return Type::TOP; 2216 } 2217 if (_useless || phase->C->post_loop_opts_phase()) { 2218 return TypeTuple::IFTRUE; 2219 } else { 2220 return bottom_type(); 2221 } 2222 } 2223 2224 #ifndef PRODUCT 2225 void ParsePredicateNode::dump_spec(outputStream* st) const { 2226 st->print(" #"); 2227 switch (_deopt_reason) { 2228 case Deoptimization::DeoptReason::Reason_predicate: 2229 st->print("Loop "); 2230 break; 2231 case Deoptimization::DeoptReason::Reason_profile_predicate: 2232 st->print("Profiled Loop "); 2233 break; 2234 case Deoptimization::DeoptReason::Reason_loop_limit_check: 2235 st->print("Loop Limit Check "); 2236 break; 2237 default: 2238 fatal("unknown kind"); 2239 } 2240 if (_useless) { 2241 st->print("#useless "); 2242 } 2243 } 2244 #endif // NOT PRODUCT