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