1 /* 2 * Copyright (c) 1997, 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 "gc/shared/barrierSet.hpp" 27 #include "gc/shared/c2/barrierSetC2.hpp" 28 #include "memory/allocation.inline.hpp" 29 #include "memory/resourceArea.hpp" 30 #include "oops/objArrayKlass.hpp" 31 #include "opto/addnode.hpp" 32 #include "opto/castnode.hpp" 33 #include "opto/cfgnode.hpp" 34 #include "opto/connode.hpp" 35 #include "opto/convertnode.hpp" 36 #include "opto/inlinetypenode.hpp" 37 #include "opto/loopnode.hpp" 38 #include "opto/machnode.hpp" 39 #include "opto/movenode.hpp" 40 #include "opto/narrowptrnode.hpp" 41 #include "opto/mulnode.hpp" 42 #include "opto/phaseX.hpp" 43 #include "opto/regalloc.hpp" 44 #include "opto/regmask.hpp" 45 #include "opto/runtime.hpp" 46 #include "opto/subnode.hpp" 47 #include "opto/vectornode.hpp" 48 #include "utilities/vmError.hpp" 49 50 // Portions of code courtesy of Clifford Click 51 52 // Optimization - Graph Style 53 54 //============================================================================= 55 //------------------------------Value------------------------------------------ 56 // Compute the type of the RegionNode. 57 const Type* RegionNode::Value(PhaseGVN* phase) const { 58 for( uint i=1; i<req(); ++i ) { // For all paths in 59 Node *n = in(i); // Get Control source 60 if( !n ) continue; // Missing inputs are TOP 61 if( phase->type(n) == Type::CONTROL ) 62 return Type::CONTROL; 63 } 64 return Type::TOP; // All paths dead? Then so are we 65 } 66 67 //------------------------------Identity--------------------------------------- 68 // Check for Region being Identity. 69 Node* RegionNode::Identity(PhaseGVN* phase) { 70 // Cannot have Region be an identity, even if it has only 1 input. 71 // Phi users cannot have their Region input folded away for them, 72 // since they need to select the proper data input 73 return this; 74 } 75 76 //------------------------------merge_region----------------------------------- 77 // If a Region flows into a Region, merge into one big happy merge. This is 78 // hard to do if there is stuff that has to happen 79 static Node *merge_region(RegionNode *region, PhaseGVN *phase) { 80 if( region->Opcode() != Op_Region ) // Do not do to LoopNodes 81 return NULL; 82 Node *progress = NULL; // Progress flag 83 PhaseIterGVN *igvn = phase->is_IterGVN(); 84 85 uint rreq = region->req(); 86 for( uint i = 1; i < rreq; i++ ) { 87 Node *r = region->in(i); 88 if( r && r->Opcode() == Op_Region && // Found a region? 89 r->in(0) == r && // Not already collapsed? 90 r != region && // Avoid stupid situations 91 r->outcnt() == 2 ) { // Self user and 'region' user only? 92 assert(!r->as_Region()->has_phi(), "no phi users"); 93 if( !progress ) { // No progress 94 if (region->has_phi()) { 95 return NULL; // Only flatten if no Phi users 96 // igvn->hash_delete( phi ); 97 } 98 igvn->hash_delete( region ); 99 progress = region; // Making progress 100 } 101 igvn->hash_delete( r ); 102 103 // Append inputs to 'r' onto 'region' 104 for( uint j = 1; j < r->req(); j++ ) { 105 // Move an input from 'r' to 'region' 106 region->add_req(r->in(j)); 107 r->set_req(j, phase->C->top()); 108 // Update phis of 'region' 109 //for( uint k = 0; k < max; k++ ) { 110 // Node *phi = region->out(k); 111 // if( phi->is_Phi() ) { 112 // phi->add_req(phi->in(i)); 113 // } 114 //} 115 116 rreq++; // One more input to Region 117 } // Found a region to merge into Region 118 igvn->_worklist.push(r); 119 // Clobber pointer to the now dead 'r' 120 region->set_req(i, phase->C->top()); 121 } 122 } 123 124 return progress; 125 } 126 127 128 129 //--------------------------------has_phi-------------------------------------- 130 // Helper function: Return any PhiNode that uses this region or NULL 131 PhiNode* RegionNode::has_phi() const { 132 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 133 Node* phi = fast_out(i); 134 if (phi->is_Phi()) { // Check for Phi users 135 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); 136 return phi->as_Phi(); // this one is good enough 137 } 138 } 139 140 return NULL; 141 } 142 143 144 //-----------------------------has_unique_phi---------------------------------- 145 // Helper function: Return the only PhiNode that uses this region or NULL 146 PhiNode* RegionNode::has_unique_phi() const { 147 // Check that only one use is a Phi 148 PhiNode* only_phi = NULL; 149 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 150 Node* phi = fast_out(i); 151 if (phi->is_Phi()) { // Check for Phi users 152 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); 153 if (only_phi == NULL) { 154 only_phi = phi->as_Phi(); 155 } else { 156 return NULL; // multiple phis 157 } 158 } 159 } 160 161 return only_phi; 162 } 163 164 165 //------------------------------check_phi_clipping----------------------------- 166 // Helper function for RegionNode's identification of FP clipping 167 // Check inputs to the Phi 168 static bool check_phi_clipping( PhiNode *phi, ConNode * &min, uint &min_idx, ConNode * &max, uint &max_idx, Node * &val, uint &val_idx ) { 169 min = NULL; 170 max = NULL; 171 val = NULL; 172 min_idx = 0; 173 max_idx = 0; 174 val_idx = 0; 175 uint phi_max = phi->req(); 176 if( phi_max == 4 ) { 177 for( uint j = 1; j < phi_max; ++j ) { 178 Node *n = phi->in(j); 179 int opcode = n->Opcode(); 180 switch( opcode ) { 181 case Op_ConI: 182 { 183 if( min == NULL ) { 184 min = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; 185 min_idx = j; 186 } else { 187 max = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; 188 max_idx = j; 189 if( min->get_int() > max->get_int() ) { 190 // Swap min and max 191 ConNode *temp; 192 uint temp_idx; 193 temp = min; min = max; max = temp; 194 temp_idx = min_idx; min_idx = max_idx; max_idx = temp_idx; 195 } 196 } 197 } 198 break; 199 default: 200 { 201 val = n; 202 val_idx = j; 203 } 204 break; 205 } 206 } 207 } 208 return ( min && max && val && (min->get_int() <= 0) && (max->get_int() >=0) ); 209 } 210 211 212 //------------------------------check_if_clipping------------------------------ 213 // Helper function for RegionNode's identification of FP clipping 214 // Check that inputs to Region come from two IfNodes, 215 // 216 // If 217 // False True 218 // If | 219 // False True | 220 // | | | 221 // RegionNode_inputs 222 // 223 static bool check_if_clipping( const RegionNode *region, IfNode * &bot_if, IfNode * &top_if ) { 224 top_if = NULL; 225 bot_if = NULL; 226 227 // Check control structure above RegionNode for (if ( if ) ) 228 Node *in1 = region->in(1); 229 Node *in2 = region->in(2); 230 Node *in3 = region->in(3); 231 // Check that all inputs are projections 232 if( in1->is_Proj() && in2->is_Proj() && in3->is_Proj() ) { 233 Node *in10 = in1->in(0); 234 Node *in20 = in2->in(0); 235 Node *in30 = in3->in(0); 236 // Check that #1 and #2 are ifTrue and ifFalse from same If 237 if( in10 != NULL && in10->is_If() && 238 in20 != NULL && in20->is_If() && 239 in30 != NULL && in30->is_If() && in10 == in20 && 240 (in1->Opcode() != in2->Opcode()) ) { 241 Node *in100 = in10->in(0); 242 Node *in1000 = (in100 != NULL && in100->is_Proj()) ? in100->in(0) : NULL; 243 // Check that control for in10 comes from other branch of IF from in3 244 if( in1000 != NULL && in1000->is_If() && 245 in30 == in1000 && (in3->Opcode() != in100->Opcode()) ) { 246 // Control pattern checks 247 top_if = (IfNode*)in1000; 248 bot_if = (IfNode*)in10; 249 } 250 } 251 } 252 253 return (top_if != NULL); 254 } 255 256 257 //------------------------------check_convf2i_clipping------------------------- 258 // Helper function for RegionNode's identification of FP clipping 259 // Verify that the value input to the phi comes from "ConvF2I; LShift; RShift" 260 static bool check_convf2i_clipping( PhiNode *phi, uint idx, ConvF2INode * &convf2i, Node *min, Node *max) { 261 convf2i = NULL; 262 263 // Check for the RShiftNode 264 Node *rshift = phi->in(idx); 265 assert( rshift, "Previous checks ensure phi input is present"); 266 if( rshift->Opcode() != Op_RShiftI ) { return false; } 267 268 // Check for the LShiftNode 269 Node *lshift = rshift->in(1); 270 assert( lshift, "Previous checks ensure phi input is present"); 271 if( lshift->Opcode() != Op_LShiftI ) { return false; } 272 273 // Check for the ConvF2INode 274 Node *conv = lshift->in(1); 275 if( conv->Opcode() != Op_ConvF2I ) { return false; } 276 277 // Check that shift amounts are only to get sign bits set after F2I 278 jint max_cutoff = max->get_int(); 279 jint min_cutoff = min->get_int(); 280 jint left_shift = lshift->in(2)->get_int(); 281 jint right_shift = rshift->in(2)->get_int(); 282 jint max_post_shift = nth_bit(BitsPerJavaInteger - left_shift - 1); 283 if( left_shift != right_shift || 284 0 > left_shift || left_shift >= BitsPerJavaInteger || 285 max_post_shift < max_cutoff || 286 max_post_shift < -min_cutoff ) { 287 // Shifts are necessary but current transformation eliminates them 288 return false; 289 } 290 291 // OK to return the result of ConvF2I without shifting 292 convf2i = (ConvF2INode*)conv; 293 return true; 294 } 295 296 297 //------------------------------check_compare_clipping------------------------- 298 // Helper function for RegionNode's identification of FP clipping 299 static bool check_compare_clipping( bool less_than, IfNode *iff, ConNode *limit, Node * & input ) { 300 Node *i1 = iff->in(1); 301 if ( !i1->is_Bool() ) { return false; } 302 BoolNode *bool1 = i1->as_Bool(); 303 if( less_than && bool1->_test._test != BoolTest::le ) { return false; } 304 else if( !less_than && bool1->_test._test != BoolTest::lt ) { return false; } 305 const Node *cmpF = bool1->in(1); 306 if( cmpF->Opcode() != Op_CmpF ) { return false; } 307 // Test that the float value being compared against 308 // is equivalent to the int value used as a limit 309 Node *nodef = cmpF->in(2); 310 if( nodef->Opcode() != Op_ConF ) { return false; } 311 jfloat conf = nodef->getf(); 312 jint coni = limit->get_int(); 313 if( ((int)conf) != coni ) { return false; } 314 input = cmpF->in(1); 315 return true; 316 } 317 318 //------------------------------is_unreachable_region-------------------------- 319 // Check if the RegionNode is part of an unsafe loop and unreachable from root. 320 bool RegionNode::is_unreachable_region(const PhaseGVN* phase) { 321 Node* top = phase->C->top(); 322 assert(req() == 2 || (req() == 3 && in(1) != NULL && in(2) == top), "sanity check arguments"); 323 if (_is_unreachable_region) { 324 // Return cached result from previous evaluation which should still be valid 325 assert(is_unreachable_from_root(phase), "walk the graph again and check if its indeed unreachable"); 326 return true; 327 } 328 329 // First, cut the simple case of fallthrough region when NONE of 330 // region's phis references itself directly or through a data node. 331 if (is_possible_unsafe_loop(phase)) { 332 // If we have a possible unsafe loop, check if the region node is actually unreachable from root. 333 if (is_unreachable_from_root(phase)) { 334 _is_unreachable_region = true; 335 return true; 336 } 337 } 338 return false; 339 } 340 341 bool RegionNode::is_possible_unsafe_loop(const PhaseGVN* phase) const { 342 uint max = outcnt(); 343 uint i; 344 for (i = 0; i < max; i++) { 345 Node* n = raw_out(i); 346 if (n != NULL && n->is_Phi()) { 347 PhiNode* phi = n->as_Phi(); 348 assert(phi->in(0) == this, "sanity check phi"); 349 if (phi->outcnt() == 0) { 350 continue; // Safe case - no loops 351 } 352 if (phi->outcnt() == 1) { 353 Node* u = phi->raw_out(0); 354 // Skip if only one use is an other Phi or Call or Uncommon trap. 355 // It is safe to consider this case as fallthrough. 356 if (u != NULL && (u->is_Phi() || u->is_CFG())) { 357 continue; 358 } 359 } 360 // Check when phi references itself directly or through an other node. 361 if (phi->as_Phi()->simple_data_loop_check(phi->in(1)) >= PhiNode::Unsafe) { 362 break; // Found possible unsafe data loop. 363 } 364 } 365 } 366 if (i >= max) { 367 return false; // An unsafe case was NOT found - don't need graph walk. 368 } 369 return true; 370 } 371 372 bool RegionNode::is_unreachable_from_root(const PhaseGVN* phase) const { 373 ResourceMark rm; 374 Node_List nstack; 375 VectorSet visited; 376 377 // Mark all control nodes reachable from root outputs 378 Node* n = (Node*)phase->C->root(); 379 nstack.push(n); 380 visited.set(n->_idx); 381 while (nstack.size() != 0) { 382 n = nstack.pop(); 383 uint max = n->outcnt(); 384 for (uint i = 0; i < max; i++) { 385 Node* m = n->raw_out(i); 386 if (m != NULL && m->is_CFG()) { 387 if (m == this) { 388 return false; // We reached the Region node - it is not dead. 389 } 390 if (!visited.test_set(m->_idx)) 391 nstack.push(m); 392 } 393 } 394 } 395 return true; // The Region node is unreachable - it is dead. 396 } 397 398 #ifdef ASSERT 399 // Is this region in an infinite subgraph? 400 // (no path to root except through false NeverBranch exit) 401 bool RegionNode::is_in_infinite_subgraph() { 402 ResourceMark rm; 403 Unique_Node_List worklist; 404 worklist.push(this); 405 return RegionNode::are_all_nodes_in_infinite_subgraph(worklist); 406 } 407 408 // Are all nodes in worklist in infinite subgraph? 409 // (no path to root except through false NeverBranch exit) 410 // worklist is directly used for the traversal 411 bool RegionNode::are_all_nodes_in_infinite_subgraph(Unique_Node_List& worklist) { 412 // BFS traversal down the CFG, except through NeverBranch exits 413 for (uint i = 0; i < worklist.size(); ++i) { 414 Node* n = worklist.at(i); 415 assert(n->is_CFG(), "only traverse CFG"); 416 if (n->is_Root()) { 417 // Found root -> there was an exit! 418 return false; 419 } else if (n->is_NeverBranch()) { 420 // Only follow the loop-internal projection, not the NeverBranch exit 421 ProjNode* proj = n->as_NeverBranch()->proj_out_or_null(0); 422 assert(proj != nullptr, "must find loop-internal projection of NeverBranch"); 423 worklist.push(proj); 424 } else { 425 // Traverse all CFG outputs 426 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 427 Node* use = n->fast_out(i); 428 if (use->is_CFG()) { 429 worklist.push(use); 430 } 431 } 432 } 433 } 434 // No exit found for any loop -> all are infinite 435 return true; 436 } 437 #endif //ASSERT 438 439 Node* PhiNode::try_clean_mem_phi(PhaseGVN *phase) { 440 // Incremental inlining + PhaseStringOpts sometimes produce: 441 // 442 // cmpP with 1 top input 443 // | 444 // If 445 // / \ 446 // IfFalse IfTrue /- Some Node 447 // \ / / / 448 // Region / /-MergeMem 449 // \---Phi 450 // 451 // 452 // It's expected by PhaseStringOpts that the Region goes away and is 453 // replaced by If's control input but because there's still a Phi, 454 // the Region stays in the graph. The top input from the cmpP is 455 // propagated forward and a subgraph that is useful goes away. The 456 // code below replaces the Phi with the MergeMem so that the Region 457 // is simplified. 458 459 if (type() == Type::MEMORY && is_diamond_phi(true)) { 460 MergeMemNode* m = NULL; 461 assert(req() == 3, "same as region"); 462 Node* r = in(0); 463 for (uint i = 1; i < 3; ++i) { 464 Node *mem = in(i); 465 if (mem && mem->is_MergeMem() && r->in(i)->outcnt() == 1) { 466 // Nothing is control-dependent on path #i except the region itself. 467 m = mem->as_MergeMem(); 468 uint j = 3 - i; 469 Node* other = in(j); 470 if (other && other == m->base_memory()) { 471 // m is a successor memory to other, and is not pinned inside the diamond, so push it out. 472 // This will allow the diamond to collapse completely. 473 return m; 474 } 475 } 476 } 477 } 478 return NULL; 479 } 480 481 //------------------------------Ideal------------------------------------------ 482 // Return a node which is more "ideal" than the current node. Must preserve 483 // the CFG, but we can still strip out dead paths. 484 Node *RegionNode::Ideal(PhaseGVN *phase, bool can_reshape) { 485 if( !can_reshape && !in(0) ) return NULL; // Already degraded to a Copy 486 assert(!in(0) || !in(0)->is_Root(), "not a specially hidden merge"); 487 488 // Check for RegionNode with no Phi users and both inputs come from either 489 // arm of the same IF. If found, then the control-flow split is useless. 490 bool has_phis = false; 491 if (can_reshape) { // Need DU info to check for Phi users 492 has_phis = (has_phi() != NULL); // Cache result 493 if (has_phis) { 494 PhiNode* phi = has_unique_phi(); 495 if (phi != NULL) { 496 Node* m = phi->try_clean_mem_phi(phase); 497 if (m != NULL) { 498 phase->is_IterGVN()->replace_node(phi, m); 499 has_phis = false; 500 } 501 } 502 } 503 504 if (!has_phis) { // No Phi users? Nothing merging? 505 for (uint i = 1; i < req()-1; i++) { 506 Node *if1 = in(i); 507 if( !if1 ) continue; 508 Node *iff = if1->in(0); 509 if( !iff || !iff->is_If() ) continue; 510 for( uint j=i+1; j<req(); j++ ) { 511 if( in(j) && in(j)->in(0) == iff && 512 if1->Opcode() != in(j)->Opcode() ) { 513 // Add the IF Projections to the worklist. They (and the IF itself) 514 // will be eliminated if dead. 515 phase->is_IterGVN()->add_users_to_worklist(iff); 516 set_req(i, iff->in(0));// Skip around the useless IF diamond 517 set_req(j, NULL); 518 return this; // Record progress 519 } 520 } 521 } 522 } 523 } 524 525 // Remove TOP or NULL input paths. If only 1 input path remains, this Region 526 // degrades to a copy. 527 bool add_to_worklist = true; 528 bool modified = false; 529 int cnt = 0; // Count of values merging 530 DEBUG_ONLY( int cnt_orig = req(); ) // Save original inputs count 531 int del_it = 0; // The last input path we delete 532 // For all inputs... 533 for( uint i=1; i<req(); ++i ){// For all paths in 534 Node *n = in(i); // Get the input 535 if( n != NULL ) { 536 // Remove useless control copy inputs 537 if( n->is_Region() && n->as_Region()->is_copy() ) { 538 set_req(i, n->nonnull_req()); 539 modified = true; 540 i--; 541 continue; 542 } 543 if( n->is_Proj() ) { // Remove useless rethrows 544 Node *call = n->in(0); 545 if (call->is_Call() && call->as_Call()->entry_point() == OptoRuntime::rethrow_stub()) { 546 set_req(i, call->in(0)); 547 modified = true; 548 i--; 549 continue; 550 } 551 } 552 if( phase->type(n) == Type::TOP ) { 553 set_req_X(i, NULL, phase); // Ignore TOP inputs 554 modified = true; 555 i--; 556 continue; 557 } 558 cnt++; // One more value merging 559 560 } else if (can_reshape) { // Else found dead path with DU info 561 PhaseIterGVN *igvn = phase->is_IterGVN(); 562 del_req(i); // Yank path from self 563 del_it = i; 564 uint max = outcnt(); 565 DUIterator j; 566 bool progress = true; 567 while(progress) { // Need to establish property over all users 568 progress = false; 569 for (j = outs(); has_out(j); j++) { 570 Node *n = out(j); 571 if( n->req() != req() && n->is_Phi() ) { 572 assert( n->in(0) == this, "" ); 573 igvn->hash_delete(n); // Yank from hash before hacking edges 574 n->set_req_X(i,NULL,igvn);// Correct DU info 575 n->del_req(i); // Yank path from Phis 576 if( max != outcnt() ) { 577 progress = true; 578 j = refresh_out_pos(j); 579 max = outcnt(); 580 } 581 } 582 } 583 } 584 add_to_worklist = false; 585 phase->is_IterGVN()->add_users_to_worklist(this); 586 i--; 587 } 588 } 589 590 if (can_reshape && cnt == 1) { 591 // Is it dead loop? 592 // If it is LoopNopde it had 2 (+1 itself) inputs and 593 // one of them was cut. The loop is dead if it was EntryContol. 594 // Loop node may have only one input because entry path 595 // is removed in PhaseIdealLoop::Dominators(). 596 assert(!this->is_Loop() || cnt_orig <= 3, "Loop node should have 3 or less inputs"); 597 if ((this->is_Loop() && (del_it == LoopNode::EntryControl || 598 (del_it == 0 && is_unreachable_region(phase)))) || 599 (!this->is_Loop() && has_phis && is_unreachable_region(phase))) { 600 // This region and therefore all nodes on the input control path(s) are unreachable 601 // from root. To avoid incomplete removal of unreachable subgraphs, walk up the CFG 602 // and aggressively replace all nodes by top. 603 PhaseIterGVN* igvn = phase->is_IterGVN(); 604 Node* top = phase->C->top(); 605 ResourceMark rm; 606 Node_List nstack; 607 VectorSet visited; 608 nstack.push(this); 609 visited.set(_idx); 610 while (nstack.size() != 0) { 611 Node* n = nstack.pop(); 612 for (uint i = 0; i < n->req(); ++i) { 613 Node* m = n->in(i); 614 assert(m != (Node*)phase->C->root(), "Should be unreachable from root"); 615 if (m != NULL && m->is_CFG() && !visited.test_set(m->_idx)) { 616 nstack.push(m); 617 } 618 } 619 if (n->is_Region()) { 620 // Eagerly replace phis with top to avoid regionless phis. 621 n->set_req(0, NULL); 622 bool progress = true; 623 uint max = n->outcnt(); 624 DUIterator j; 625 while (progress) { 626 progress = false; 627 for (j = n->outs(); n->has_out(j); j++) { 628 Node* u = n->out(j); 629 if (u->is_Phi()) { 630 igvn->replace_node(u, top); 631 if (max != n->outcnt()) { 632 progress = true; 633 j = n->refresh_out_pos(j); 634 max = n->outcnt(); 635 } 636 } 637 } 638 } 639 } 640 igvn->replace_node(n, top); 641 } 642 return NULL; 643 } 644 } 645 646 if( cnt <= 1 ) { // Only 1 path in? 647 set_req(0, NULL); // Null control input for region copy 648 if( cnt == 0 && !can_reshape) { // Parse phase - leave the node as it is. 649 // No inputs or all inputs are NULL. 650 return NULL; 651 } else if (can_reshape) { // Optimization phase - remove the node 652 PhaseIterGVN *igvn = phase->is_IterGVN(); 653 // Strip mined (inner) loop is going away, remove outer loop. 654 if (is_CountedLoop() && 655 as_Loop()->is_strip_mined()) { 656 Node* outer_sfpt = as_CountedLoop()->outer_safepoint(); 657 Node* outer_out = as_CountedLoop()->outer_loop_exit(); 658 if (outer_sfpt != NULL && outer_out != NULL) { 659 Node* in = outer_sfpt->in(0); 660 igvn->replace_node(outer_out, in); 661 LoopNode* outer = as_CountedLoop()->outer_loop(); 662 igvn->replace_input_of(outer, LoopNode::LoopBackControl, igvn->C->top()); 663 } 664 } 665 if (is_CountedLoop()) { 666 Node* opaq = as_CountedLoop()->is_canonical_loop_entry(); 667 if (opaq != NULL) { 668 // This is not a loop anymore. No need to keep the Opaque1 node on the test that guards the loop as it won't be 669 // subject to further loop opts. 670 assert(opaq->Opcode() == Op_OpaqueZeroTripGuard, ""); 671 igvn->replace_node(opaq, opaq->in(1)); 672 } 673 } 674 Node *parent_ctrl; 675 if( cnt == 0 ) { 676 assert( req() == 1, "no inputs expected" ); 677 // During IGVN phase such region will be subsumed by TOP node 678 // so region's phis will have TOP as control node. 679 // Kill phis here to avoid it. 680 // Also set other user's input to top. 681 parent_ctrl = phase->C->top(); 682 } else { 683 // The fallthrough case since we already checked dead loops above. 684 parent_ctrl = in(1); 685 assert(parent_ctrl != NULL, "Region is a copy of some non-null control"); 686 assert(parent_ctrl != this, "Close dead loop"); 687 } 688 if (add_to_worklist) { 689 igvn->add_users_to_worklist(this); // Check for further allowed opts 690 } 691 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) { 692 Node* n = last_out(i); 693 igvn->hash_delete(n); // Remove from worklist before modifying edges 694 if (n->outcnt() == 0) { 695 int uses_found = n->replace_edge(this, phase->C->top(), igvn); 696 if (uses_found > 1) { // (--i) done at the end of the loop. 697 i -= (uses_found - 1); 698 } 699 continue; 700 } 701 if( n->is_Phi() ) { // Collapse all Phis 702 // Eagerly replace phis to avoid regionless phis. 703 Node* in; 704 if( cnt == 0 ) { 705 assert( n->req() == 1, "No data inputs expected" ); 706 in = parent_ctrl; // replaced by top 707 } else { 708 assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" ); 709 in = n->in(1); // replaced by unique input 710 if( n->as_Phi()->is_unsafe_data_reference(in) ) 711 in = phase->C->top(); // replaced by top 712 } 713 igvn->replace_node(n, in); 714 } 715 else if( n->is_Region() ) { // Update all incoming edges 716 assert(n != this, "Must be removed from DefUse edges"); 717 int uses_found = n->replace_edge(this, parent_ctrl, igvn); 718 if (uses_found > 1) { // (--i) done at the end of the loop. 719 i -= (uses_found - 1); 720 } 721 } 722 else { 723 assert(n->in(0) == this, "Expect RegionNode to be control parent"); 724 n->set_req(0, parent_ctrl); 725 } 726 #ifdef ASSERT 727 for( uint k=0; k < n->req(); k++ ) { 728 assert(n->in(k) != this, "All uses of RegionNode should be gone"); 729 } 730 #endif 731 } 732 // Remove the RegionNode itself from DefUse info 733 igvn->remove_dead_node(this); 734 return NULL; 735 } 736 return this; // Record progress 737 } 738 739 740 // If a Region flows into a Region, merge into one big happy merge. 741 if (can_reshape) { 742 Node *m = merge_region(this, phase); 743 if (m != NULL) return m; 744 } 745 746 // Check if this region is the root of a clipping idiom on floats 747 if( ConvertFloat2IntClipping && can_reshape && req() == 4 ) { 748 // Check that only one use is a Phi and that it simplifies to two constants + 749 PhiNode* phi = has_unique_phi(); 750 if (phi != NULL) { // One Phi user 751 // Check inputs to the Phi 752 ConNode *min; 753 ConNode *max; 754 Node *val; 755 uint min_idx; 756 uint max_idx; 757 uint val_idx; 758 if( check_phi_clipping( phi, min, min_idx, max, max_idx, val, val_idx ) ) { 759 IfNode *top_if; 760 IfNode *bot_if; 761 if( check_if_clipping( this, bot_if, top_if ) ) { 762 // Control pattern checks, now verify compares 763 Node *top_in = NULL; // value being compared against 764 Node *bot_in = NULL; 765 if( check_compare_clipping( true, bot_if, min, bot_in ) && 766 check_compare_clipping( false, top_if, max, top_in ) ) { 767 if( bot_in == top_in ) { 768 PhaseIterGVN *gvn = phase->is_IterGVN(); 769 assert( gvn != NULL, "Only had DefUse info in IterGVN"); 770 // Only remaining check is that bot_in == top_in == (Phi's val + mods) 771 772 // Check for the ConvF2INode 773 ConvF2INode *convf2i; 774 if( check_convf2i_clipping( phi, val_idx, convf2i, min, max ) && 775 convf2i->in(1) == bot_in ) { 776 // Matched pattern, including LShiftI; RShiftI, replace with integer compares 777 // max test 778 Node *cmp = gvn->register_new_node_with_optimizer(new CmpINode( convf2i, min )); 779 Node *boo = gvn->register_new_node_with_optimizer(new BoolNode( cmp, BoolTest::lt )); 780 IfNode *iff = (IfNode*)gvn->register_new_node_with_optimizer(new IfNode( top_if->in(0), boo, PROB_UNLIKELY_MAG(5), top_if->_fcnt )); 781 Node *if_min= gvn->register_new_node_with_optimizer(new IfTrueNode (iff)); 782 Node *ifF = gvn->register_new_node_with_optimizer(new IfFalseNode(iff)); 783 // min test 784 cmp = gvn->register_new_node_with_optimizer(new CmpINode( convf2i, max )); 785 boo = gvn->register_new_node_with_optimizer(new BoolNode( cmp, BoolTest::gt )); 786 iff = (IfNode*)gvn->register_new_node_with_optimizer(new IfNode( ifF, boo, PROB_UNLIKELY_MAG(5), bot_if->_fcnt )); 787 Node *if_max= gvn->register_new_node_with_optimizer(new IfTrueNode (iff)); 788 ifF = gvn->register_new_node_with_optimizer(new IfFalseNode(iff)); 789 // update input edges to region node 790 set_req_X( min_idx, if_min, gvn ); 791 set_req_X( max_idx, if_max, gvn ); 792 set_req_X( val_idx, ifF, gvn ); 793 // remove unnecessary 'LShiftI; RShiftI' idiom 794 gvn->hash_delete(phi); 795 phi->set_req_X( val_idx, convf2i, gvn ); 796 gvn->hash_find_insert(phi); 797 // Return transformed region node 798 return this; 799 } 800 } 801 } 802 } 803 } 804 } 805 } 806 807 if (can_reshape) { 808 modified |= optimize_trichotomy(phase->is_IterGVN()); 809 } 810 811 return modified ? this : NULL; 812 } 813 814 //------------------------------optimize_trichotomy-------------------------- 815 // Optimize nested comparisons of the following kind: 816 // 817 // int compare(int a, int b) { 818 // return (a < b) ? -1 : (a == b) ? 0 : 1; 819 // } 820 // 821 // Shape 1: 822 // if (compare(a, b) == 1) { ... } -> if (a > b) { ... } 823 // 824 // Shape 2: 825 // if (compare(a, b) == 0) { ... } -> if (a == b) { ... } 826 // 827 // Above code leads to the following IR shapes where both Ifs compare the 828 // same value and two out of three region inputs idx1 and idx2 map to 829 // the same value and control flow. 830 // 831 // (1) If (2) If 832 // / \ / \ 833 // Proj Proj Proj Proj 834 // | \ | \ 835 // | If | If If 836 // | / \ | / \ / \ 837 // | Proj Proj | Proj Proj ==> Proj Proj 838 // | / / \ | / | / 839 // Region / \ | / | / 840 // \ / \ | / | / 841 // Region Region Region 842 // 843 // The method returns true if 'this' is modified and false otherwise. 844 bool RegionNode::optimize_trichotomy(PhaseIterGVN* igvn) { 845 int idx1 = 1, idx2 = 2; 846 Node* region = NULL; 847 if (req() == 3 && in(1) != NULL && in(2) != NULL) { 848 // Shape 1: Check if one of the inputs is a region that merges two control 849 // inputs and has no other users (especially no Phi users). 850 region = in(1)->isa_Region() ? in(1) : in(2)->isa_Region(); 851 if (region == NULL || region->outcnt() != 2 || region->req() != 3) { 852 return false; // No suitable region input found 853 } 854 } else if (req() == 4) { 855 // Shape 2: Check if two control inputs map to the same value of the unique phi 856 // user and treat these as if they would come from another region (shape (1)). 857 PhiNode* phi = has_unique_phi(); 858 if (phi == NULL) { 859 return false; // No unique phi user 860 } 861 if (phi->in(idx1) != phi->in(idx2)) { 862 idx2 = 3; 863 if (phi->in(idx1) != phi->in(idx2)) { 864 idx1 = 2; 865 if (phi->in(idx1) != phi->in(idx2)) { 866 return false; // No equal phi inputs found 867 } 868 } 869 } 870 assert(phi->in(idx1) == phi->in(idx2), "must be"); // Region is merging same value 871 region = this; 872 } 873 if (region == NULL || region->in(idx1) == NULL || region->in(idx2) == NULL) { 874 return false; // Region does not merge two control inputs 875 } 876 // At this point we know that region->in(idx1) and region->(idx2) map to the same 877 // value and control flow. Now search for ifs that feed into these region inputs. 878 ProjNode* proj1 = region->in(idx1)->isa_Proj(); 879 ProjNode* proj2 = region->in(idx2)->isa_Proj(); 880 if (proj1 == NULL || proj1->outcnt() != 1 || 881 proj2 == NULL || proj2->outcnt() != 1) { 882 return false; // No projection inputs with region as unique user found 883 } 884 assert(proj1 != proj2, "should be different projections"); 885 IfNode* iff1 = proj1->in(0)->isa_If(); 886 IfNode* iff2 = proj2->in(0)->isa_If(); 887 if (iff1 == NULL || iff1->outcnt() != 2 || 888 iff2 == NULL || iff2->outcnt() != 2) { 889 return false; // No ifs found 890 } 891 if (iff1 == iff2) { 892 igvn->add_users_to_worklist(iff1); // Make sure dead if is eliminated 893 igvn->replace_input_of(region, idx1, iff1->in(0)); 894 igvn->replace_input_of(region, idx2, igvn->C->top()); 895 return (region == this); // Remove useless if (both projections map to the same control/value) 896 } 897 BoolNode* bol1 = iff1->in(1)->isa_Bool(); 898 BoolNode* bol2 = iff2->in(1)->isa_Bool(); 899 if (bol1 == NULL || bol2 == NULL) { 900 return false; // No bool inputs found 901 } 902 Node* cmp1 = bol1->in(1); 903 Node* cmp2 = bol2->in(1); 904 bool commute = false; 905 if (!cmp1->is_Cmp() || !cmp2->is_Cmp()) { 906 return false; // No comparison 907 } else if (cmp1->Opcode() == Op_CmpF || cmp1->Opcode() == Op_CmpD || 908 cmp2->Opcode() == Op_CmpF || cmp2->Opcode() == Op_CmpD || 909 cmp1->Opcode() == Op_CmpP || cmp1->Opcode() == Op_CmpN || 910 cmp2->Opcode() == Op_CmpP || cmp2->Opcode() == Op_CmpN || 911 cmp1->is_SubTypeCheck() || cmp2->is_SubTypeCheck() || 912 cmp1->is_FlatArrayCheck() || cmp2->is_FlatArrayCheck()) { 913 // Floats and pointers don't exactly obey trichotomy. To be on the safe side, don't transform their tests. 914 // SubTypeCheck is not commutative 915 return false; 916 } else if (cmp1 != cmp2) { 917 if (cmp1->in(1) == cmp2->in(2) && 918 cmp1->in(2) == cmp2->in(1)) { 919 commute = true; // Same but swapped inputs, commute the test 920 } else { 921 return false; // Ifs are not comparing the same values 922 } 923 } 924 proj1 = proj1->other_if_proj(); 925 proj2 = proj2->other_if_proj(); 926 if (!((proj1->unique_ctrl_out_or_null() == iff2 && 927 proj2->unique_ctrl_out_or_null() == this) || 928 (proj2->unique_ctrl_out_or_null() == iff1 && 929 proj1->unique_ctrl_out_or_null() == this))) { 930 return false; // Ifs are not connected through other projs 931 } 932 // Found 'iff -> proj -> iff -> proj -> this' shape where all other projs are merged 933 // through 'region' and map to the same value. Merge the boolean tests and replace 934 // the ifs by a single comparison. 935 BoolTest test1 = (proj1->_con == 1) ? bol1->_test : bol1->_test.negate(); 936 BoolTest test2 = (proj2->_con == 1) ? bol2->_test : bol2->_test.negate(); 937 test1 = commute ? test1.commute() : test1; 938 // After possibly commuting test1, if we can merge test1 & test2, then proj2/iff2/bol2 are the nodes to refine. 939 BoolTest::mask res = test1.merge(test2); 940 if (res == BoolTest::illegal) { 941 return false; // Unable to merge tests 942 } 943 // Adjust iff1 to always pass (only iff2 will remain) 944 igvn->replace_input_of(iff1, 1, igvn->intcon(proj1->_con)); 945 if (res == BoolTest::never) { 946 // Merged test is always false, adjust iff2 to always fail 947 igvn->replace_input_of(iff2, 1, igvn->intcon(1 - proj2->_con)); 948 } else { 949 // Replace bool input of iff2 with merged test 950 BoolNode* new_bol = new BoolNode(bol2->in(1), res); 951 igvn->replace_input_of(iff2, 1, igvn->transform((proj2->_con == 1) ? new_bol : new_bol->negate(igvn))); 952 if (new_bol->outcnt() == 0) { 953 igvn->remove_dead_node(new_bol); 954 } 955 } 956 return false; 957 } 958 959 const RegMask &RegionNode::out_RegMask() const { 960 return RegMask::Empty; 961 } 962 963 // Find the one non-null required input. RegionNode only 964 Node *Node::nonnull_req() const { 965 assert( is_Region(), "" ); 966 for( uint i = 1; i < _cnt; i++ ) 967 if( in(i) ) 968 return in(i); 969 ShouldNotReachHere(); 970 return NULL; 971 } 972 973 974 //============================================================================= 975 // note that these functions assume that the _adr_type field is flattened 976 uint PhiNode::hash() const { 977 const Type* at = _adr_type; 978 return TypeNode::hash() + (at ? at->hash() : 0); 979 } 980 bool PhiNode::cmp( const Node &n ) const { 981 return TypeNode::cmp(n) && _adr_type == ((PhiNode&)n)._adr_type; 982 } 983 static inline 984 const TypePtr* flatten_phi_adr_type(const TypePtr* at) { 985 if (at == NULL || at == TypePtr::BOTTOM) return at; 986 return Compile::current()->alias_type(at)->adr_type(); 987 } 988 989 //----------------------------make--------------------------------------------- 990 // create a new phi with edges matching r and set (initially) to x 991 PhiNode* PhiNode::make(Node* r, Node* x, const Type *t, const TypePtr* at) { 992 uint preds = r->req(); // Number of predecessor paths 993 assert(t != Type::MEMORY || at == flatten_phi_adr_type(at) || (flatten_phi_adr_type(at) == TypeAryPtr::INLINES && Compile::current()->flattened_accesses_share_alias()), "flatten at"); 994 PhiNode* p = new PhiNode(r, t, at); 995 for (uint j = 1; j < preds; j++) { 996 // Fill in all inputs, except those which the region does not yet have 997 if (r->in(j) != NULL) 998 p->init_req(j, x); 999 } 1000 return p; 1001 } 1002 PhiNode* PhiNode::make(Node* r, Node* x) { 1003 const Type* t = x->bottom_type(); 1004 const TypePtr* at = NULL; 1005 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); 1006 return make(r, x, t, at); 1007 } 1008 PhiNode* PhiNode::make_blank(Node* r, Node* x) { 1009 const Type* t = x->bottom_type(); 1010 const TypePtr* at = NULL; 1011 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); 1012 return new PhiNode(r, t, at); 1013 } 1014 1015 1016 //------------------------slice_memory----------------------------------------- 1017 // create a new phi with narrowed memory type 1018 PhiNode* PhiNode::slice_memory(const TypePtr* adr_type) const { 1019 PhiNode* mem = (PhiNode*) clone(); 1020 *(const TypePtr**)&mem->_adr_type = adr_type; 1021 // convert self-loops, or else we get a bad graph 1022 for (uint i = 1; i < req(); i++) { 1023 if ((const Node*)in(i) == this) mem->set_req(i, mem); 1024 } 1025 mem->verify_adr_type(); 1026 return mem; 1027 } 1028 1029 //------------------------split_out_instance----------------------------------- 1030 // Split out an instance type from a bottom phi. 1031 PhiNode* PhiNode::split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const { 1032 const TypeOopPtr *t_oop = at->isa_oopptr(); 1033 assert(t_oop != NULL && t_oop->is_known_instance(), "expecting instance oopptr"); 1034 1035 // Check if an appropriate node already exists. 1036 Node *region = in(0); 1037 for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) { 1038 Node* use = region->fast_out(k); 1039 if( use->is_Phi()) { 1040 PhiNode *phi2 = use->as_Phi(); 1041 if (phi2->type() == Type::MEMORY && phi2->adr_type() == at) { 1042 return phi2; 1043 } 1044 } 1045 } 1046 Compile *C = igvn->C; 1047 Arena *a = Thread::current()->resource_area(); 1048 Node_Array node_map = new Node_Array(a); 1049 Node_Stack stack(a, C->live_nodes() >> 4); 1050 PhiNode *nphi = slice_memory(at); 1051 igvn->register_new_node_with_optimizer( nphi ); 1052 node_map.map(_idx, nphi); 1053 stack.push((Node *)this, 1); 1054 while(!stack.is_empty()) { 1055 PhiNode *ophi = stack.node()->as_Phi(); 1056 uint i = stack.index(); 1057 assert(i >= 1, "not control edge"); 1058 stack.pop(); 1059 nphi = node_map[ophi->_idx]->as_Phi(); 1060 for (; i < ophi->req(); i++) { 1061 Node *in = ophi->in(i); 1062 if (in == NULL || igvn->type(in) == Type::TOP) 1063 continue; 1064 Node *opt = MemNode::optimize_simple_memory_chain(in, t_oop, NULL, igvn); 1065 PhiNode *optphi = opt->is_Phi() ? opt->as_Phi() : NULL; 1066 if (optphi != NULL && optphi->adr_type() == TypePtr::BOTTOM) { 1067 opt = node_map[optphi->_idx]; 1068 if (opt == NULL) { 1069 stack.push(ophi, i); 1070 nphi = optphi->slice_memory(at); 1071 igvn->register_new_node_with_optimizer( nphi ); 1072 node_map.map(optphi->_idx, nphi); 1073 ophi = optphi; 1074 i = 0; // will get incremented at top of loop 1075 continue; 1076 } 1077 } 1078 nphi->set_req(i, opt); 1079 } 1080 } 1081 return nphi; 1082 } 1083 1084 //------------------------verify_adr_type-------------------------------------- 1085 #ifdef ASSERT 1086 void PhiNode::verify_adr_type(VectorSet& visited, const TypePtr* at) const { 1087 if (visited.test_set(_idx)) return; //already visited 1088 1089 // recheck constructor invariants: 1090 verify_adr_type(false); 1091 1092 // recheck local phi/phi consistency: 1093 assert(_adr_type == at || _adr_type == TypePtr::BOTTOM, 1094 "adr_type must be consistent across phi nest"); 1095 1096 // walk around 1097 for (uint i = 1; i < req(); i++) { 1098 Node* n = in(i); 1099 if (n == NULL) continue; 1100 const Node* np = in(i); 1101 if (np->is_Phi()) { 1102 np->as_Phi()->verify_adr_type(visited, at); 1103 } else if (n->bottom_type() == Type::TOP 1104 || (n->is_Mem() && n->in(MemNode::Address)->bottom_type() == Type::TOP)) { 1105 // ignore top inputs 1106 } else { 1107 const TypePtr* nat = flatten_phi_adr_type(n->adr_type()); 1108 // recheck phi/non-phi consistency at leaves: 1109 assert((nat != NULL) == (at != NULL), ""); 1110 assert(nat == at || nat == TypePtr::BOTTOM, 1111 "adr_type must be consistent at leaves of phi nest"); 1112 } 1113 } 1114 } 1115 1116 // Verify a whole nest of phis rooted at this one. 1117 void PhiNode::verify_adr_type(bool recursive) const { 1118 if (VMError::is_error_reported()) return; // muzzle asserts when debugging an error 1119 if (Node::in_dump()) return; // muzzle asserts when printing 1120 1121 assert((_type == Type::MEMORY) == (_adr_type != NULL), "adr_type for memory phis only"); 1122 // Flat array element shouldn't get their own memory slice until flattened_accesses_share_alias is cleared. 1123 // It could be the graph has no loads/stores and flattened_accesses_share_alias is never cleared. EA could still 1124 // creates per element Phis but that wouldn't be a problem as there are no memory accesses for that array. 1125 assert(_adr_type == NULL || _adr_type->isa_aryptr() == NULL || 1126 _adr_type->is_aryptr()->is_known_instance() || 1127 !_adr_type->is_aryptr()->is_flat() || 1128 !Compile::current()->flattened_accesses_share_alias() || 1129 _adr_type == TypeAryPtr::INLINES, "flat array element shouldn't get its own slice yet"); 1130 1131 if (!VerifyAliases) return; // verify thoroughly only if requested 1132 1133 assert(_adr_type == flatten_phi_adr_type(_adr_type), 1134 "Phi::adr_type must be pre-normalized"); 1135 1136 if (recursive) { 1137 VectorSet visited; 1138 verify_adr_type(visited, _adr_type); 1139 } 1140 } 1141 #endif 1142 1143 1144 //------------------------------Value------------------------------------------ 1145 // Compute the type of the PhiNode 1146 const Type* PhiNode::Value(PhaseGVN* phase) const { 1147 Node *r = in(0); // RegionNode 1148 if( !r ) // Copy or dead 1149 return in(1) ? phase->type(in(1)) : Type::TOP; 1150 1151 // Note: During parsing, phis are often transformed before their regions. 1152 // This means we have to use type_or_null to defend against untyped regions. 1153 if( phase->type_or_null(r) == Type::TOP ) // Dead code? 1154 return Type::TOP; 1155 1156 // Check for trip-counted loop. If so, be smarter. 1157 BaseCountedLoopNode* l = r->is_BaseCountedLoop() ? r->as_BaseCountedLoop() : NULL; 1158 if (l && ((const Node*)l->phi() == this)) { // Trip counted loop! 1159 // protect against init_trip() or limit() returning NULL 1160 if (l->can_be_counted_loop(phase)) { 1161 const Node* init = l->init_trip(); 1162 const Node* limit = l->limit(); 1163 const Node* stride = l->stride(); 1164 if (init != NULL && limit != NULL && stride != NULL) { 1165 const TypeInteger* lo = phase->type(init)->isa_integer(l->bt()); 1166 const TypeInteger* hi = phase->type(limit)->isa_integer(l->bt()); 1167 const TypeInteger* stride_t = phase->type(stride)->isa_integer(l->bt()); 1168 if (lo != NULL && hi != NULL && stride_t != NULL) { // Dying loops might have TOP here 1169 assert(stride_t->is_con(), "bad stride type"); 1170 BoolTest::mask bt = l->loopexit()->test_trip(); 1171 // If the loop exit condition is "not equal", the condition 1172 // would not trigger if init > limit (if stride > 0) or if 1173 // init < limit if (stride > 0) so we can't deduce bounds 1174 // for the iv from the exit condition. 1175 if (bt != BoolTest::ne) { 1176 jlong stride_con = stride_t->get_con_as_long(l->bt()); 1177 if (stride_con < 0) { // Down-counter loop 1178 swap(lo, hi); 1179 jlong iv_range_lower_limit = lo->lo_as_long(); 1180 // Prevent overflow when adding one below 1181 if (iv_range_lower_limit < max_signed_integer(l->bt())) { 1182 // The loop exit condition is: iv + stride > limit (iv is this Phi). So the loop iterates until 1183 // iv + stride <= limit 1184 // We know that: limit >= lo->lo_as_long() and stride <= -1 1185 // So when the loop exits, iv has to be at most lo->lo_as_long() + 1 1186 iv_range_lower_limit += 1; // lo is after decrement 1187 // Exact bounds for the phi can be computed when ABS(stride) greater than 1 if bounds are constant. 1188 if (lo->is_con() && hi->is_con() && hi->lo_as_long() > lo->hi_as_long() && stride_con != -1) { 1189 julong uhi = static_cast<julong>(hi->lo_as_long()); 1190 julong ulo = static_cast<julong>(lo->hi_as_long()); 1191 julong diff = ((uhi - ulo - 1) / (-stride_con)) * (-stride_con); 1192 julong ufirst = hi->lo_as_long() - diff; 1193 iv_range_lower_limit = reinterpret_cast<jlong &>(ufirst); 1194 assert(iv_range_lower_limit >= lo->lo_as_long() + 1, "should end up with narrower range"); 1195 } 1196 } 1197 return TypeInteger::make(MIN2(iv_range_lower_limit, hi->lo_as_long()), hi->hi_as_long(), 3, l->bt())->filter_speculative(_type); 1198 } else if (stride_con >= 0) { 1199 jlong iv_range_upper_limit = hi->hi_as_long(); 1200 // Prevent overflow when subtracting one below 1201 if (iv_range_upper_limit > min_signed_integer(l->bt())) { 1202 // The loop exit condition is: iv + stride < limit (iv is this Phi). So the loop iterates until 1203 // iv + stride >= limit 1204 // We know that: limit <= hi->hi_as_long() and stride >= 1 1205 // So when the loop exits, iv has to be at most hi->hi_as_long() - 1 1206 iv_range_upper_limit -= 1; 1207 // Exact bounds for the phi can be computed when ABS(stride) greater than 1 if bounds are constant. 1208 if (lo->is_con() && hi->is_con() && hi->lo_as_long() > lo->hi_as_long() && stride_con != 1) { 1209 julong uhi = static_cast<julong>(hi->lo_as_long()); 1210 julong ulo = static_cast<julong>(lo->hi_as_long()); 1211 julong diff = ((uhi - ulo - 1) / stride_con) * stride_con; 1212 julong ulast = lo->hi_as_long() + diff; 1213 iv_range_upper_limit = reinterpret_cast<jlong &>(ulast); 1214 assert(iv_range_upper_limit <= hi->hi_as_long() - 1, "should end up with narrower range"); 1215 } 1216 } 1217 return TypeInteger::make(lo->lo_as_long(), MAX2(lo->hi_as_long(), iv_range_upper_limit), 3, l->bt())->filter_speculative(_type); 1218 } 1219 } 1220 } 1221 } 1222 } else if (l->in(LoopNode::LoopBackControl) != NULL && 1223 in(LoopNode::EntryControl) != NULL && 1224 phase->type(l->in(LoopNode::LoopBackControl)) == Type::TOP) { 1225 // During CCP, if we saturate the type of a counted loop's Phi 1226 // before the special code for counted loop above has a chance 1227 // to run (that is as long as the type of the backedge's control 1228 // is top), we might end up with non monotonic types 1229 return phase->type(in(LoopNode::EntryControl))->filter_speculative(_type); 1230 } 1231 } 1232 1233 // Default case: merge all inputs 1234 const Type *t = Type::TOP; // Merged type starting value 1235 for (uint i = 1; i < req(); ++i) {// For all paths in 1236 // Reachable control path? 1237 if (r->in(i) && phase->type(r->in(i)) == Type::CONTROL) { 1238 const Type* ti = phase->type(in(i)); 1239 t = t->meet_speculative(ti); 1240 } 1241 } 1242 1243 // The worst-case type (from ciTypeFlow) should be consistent with "t". 1244 // That is, we expect that "t->higher_equal(_type)" holds true. 1245 // There are various exceptions: 1246 // - Inputs which are phis might in fact be widened unnecessarily. 1247 // For example, an input might be a widened int while the phi is a short. 1248 // - Inputs might be BotPtrs but this phi is dependent on a null check, 1249 // and postCCP has removed the cast which encodes the result of the check. 1250 // - The type of this phi is an interface, and the inputs are classes. 1251 // - Value calls on inputs might produce fuzzy results. 1252 // (Occurrences of this case suggest improvements to Value methods.) 1253 // 1254 // It is not possible to see Type::BOTTOM values as phi inputs, 1255 // because the ciTypeFlow pre-pass produces verifier-quality types. 1256 const Type* ft = t->filter_speculative(_type); // Worst case type 1257 1258 #ifdef ASSERT 1259 // The following logic has been moved into TypeOopPtr::filter. 1260 const Type* jt = t->join_speculative(_type); 1261 if (jt->empty()) { // Emptied out??? 1262 // Otherwise it's something stupid like non-overlapping int ranges 1263 // found on dying counted loops. 1264 assert(ft == Type::TOP, ""); // Canonical empty value 1265 } 1266 1267 else { 1268 1269 if (jt != ft && jt->base() == ft->base()) { 1270 if (jt->isa_int() && 1271 jt->is_int()->_lo == ft->is_int()->_lo && 1272 jt->is_int()->_hi == ft->is_int()->_hi) 1273 jt = ft; 1274 if (jt->isa_long() && 1275 jt->is_long()->_lo == ft->is_long()->_lo && 1276 jt->is_long()->_hi == ft->is_long()->_hi) 1277 jt = ft; 1278 } 1279 if (jt != ft) { 1280 tty->print("merge type: "); t->dump(); tty->cr(); 1281 tty->print("kill type: "); _type->dump(); tty->cr(); 1282 tty->print("join type: "); jt->dump(); tty->cr(); 1283 tty->print("filter type: "); ft->dump(); tty->cr(); 1284 } 1285 assert(jt == ft, ""); 1286 } 1287 #endif //ASSERT 1288 1289 // Deal with conversion problems found in data loops. 1290 ft = phase->saturate(ft, phase->type_or_null(this), _type); 1291 1292 return ft; 1293 } 1294 1295 1296 //------------------------------is_diamond_phi--------------------------------- 1297 // Does this Phi represent a simple well-shaped diamond merge? Return the 1298 // index of the true path or 0 otherwise. 1299 // If check_control_only is true, do not inspect the If node at the 1300 // top, and return -1 (not an edge number) on success. 1301 int PhiNode::is_diamond_phi(bool check_control_only) const { 1302 // Check for a 2-path merge 1303 Node *region = in(0); 1304 if( !region ) return 0; 1305 if( region->req() != 3 ) return 0; 1306 if( req() != 3 ) return 0; 1307 // Check that both paths come from the same If 1308 Node *ifp1 = region->in(1); 1309 Node *ifp2 = region->in(2); 1310 if( !ifp1 || !ifp2 ) return 0; 1311 Node *iff = ifp1->in(0); 1312 if( !iff || !iff->is_If() ) return 0; 1313 if( iff != ifp2->in(0) ) return 0; 1314 if (check_control_only) return -1; 1315 // Check for a proper bool/cmp 1316 const Node *b = iff->in(1); 1317 if( !b->is_Bool() ) return 0; 1318 const Node *cmp = b->in(1); 1319 if( !cmp->is_Cmp() ) return 0; 1320 1321 // Check for branching opposite expected 1322 if( ifp2->Opcode() == Op_IfTrue ) { 1323 assert( ifp1->Opcode() == Op_IfFalse, "" ); 1324 return 2; 1325 } else { 1326 assert( ifp1->Opcode() == Op_IfTrue, "" ); 1327 return 1; 1328 } 1329 } 1330 1331 //----------------------------check_cmove_id----------------------------------- 1332 // Check for CMove'ing a constant after comparing against the constant. 1333 // Happens all the time now, since if we compare equality vs a constant in 1334 // the parser, we "know" the variable is constant on one path and we force 1335 // it. Thus code like "if( x==0 ) {/*EMPTY*/}" ends up inserting a 1336 // conditional move: "x = (x==0)?0:x;". Yucko. This fix is slightly more 1337 // general in that we don't need constants. Since CMove's are only inserted 1338 // in very special circumstances, we do it here on generic Phi's. 1339 Node* PhiNode::is_cmove_id(PhaseTransform* phase, int true_path) { 1340 assert(true_path !=0, "only diamond shape graph expected"); 1341 1342 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1343 // phi->region->if_proj->ifnode->bool->cmp 1344 Node* region = in(0); 1345 Node* iff = region->in(1)->in(0); 1346 BoolNode* b = iff->in(1)->as_Bool(); 1347 Node* cmp = b->in(1); 1348 Node* tval = in(true_path); 1349 Node* fval = in(3-true_path); 1350 Node* id = CMoveNode::is_cmove_id(phase, cmp, tval, fval, b); 1351 if (id == NULL) 1352 return NULL; 1353 1354 // Either value might be a cast that depends on a branch of 'iff'. 1355 // Since the 'id' value will float free of the diamond, either 1356 // decast or return failure. 1357 Node* ctl = id->in(0); 1358 if (ctl != NULL && ctl->in(0) == iff) { 1359 if (id->is_ConstraintCast()) { 1360 return id->in(1); 1361 } else { 1362 // Don't know how to disentangle this value. 1363 return NULL; 1364 } 1365 } 1366 1367 return id; 1368 } 1369 1370 //------------------------------Identity--------------------------------------- 1371 // Check for Region being Identity. 1372 Node* PhiNode::Identity(PhaseGVN* phase) { 1373 // Check for no merging going on 1374 // (There used to be special-case code here when this->region->is_Loop. 1375 // It would check for a tributary phi on the backedge that the main phi 1376 // trivially, perhaps with a single cast. The unique_input method 1377 // does all this and more, by reducing such tributaries to 'this'.) 1378 Node* uin = unique_input(phase, false); 1379 if (uin != NULL) { 1380 return uin; 1381 } 1382 1383 int true_path = is_diamond_phi(); 1384 // Delay CMove'ing identity if Ideal has not had the chance to handle unsafe cases, yet. 1385 if (true_path != 0 && !(phase->is_IterGVN() && wait_for_region_igvn(phase))) { 1386 Node* id = is_cmove_id(phase, true_path); 1387 if (id != NULL) { 1388 return id; 1389 } 1390 } 1391 1392 if (phase->is_IterGVN()) { 1393 Node* m = try_clean_mem_phi(phase); 1394 if (m != NULL) { 1395 return m; 1396 } 1397 } 1398 1399 1400 // Looking for phis with identical inputs. If we find one that has 1401 // type TypePtr::BOTTOM, replace the current phi with the bottom phi. 1402 if (phase->is_IterGVN() && type() == Type::MEMORY && adr_type() != 1403 TypePtr::BOTTOM && !adr_type()->is_known_instance()) { 1404 uint phi_len = req(); 1405 Node* phi_reg = region(); 1406 for (DUIterator_Fast imax, i = phi_reg->fast_outs(imax); i < imax; i++) { 1407 Node* u = phi_reg->fast_out(i); 1408 if (u->is_Phi() && u->as_Phi()->type() == Type::MEMORY && 1409 u->adr_type() == TypePtr::BOTTOM && u->in(0) == phi_reg && 1410 u->req() == phi_len) { 1411 for (uint j = 1; j < phi_len; j++) { 1412 if (in(j) != u->in(j)) { 1413 u = NULL; 1414 break; 1415 } 1416 } 1417 if (u != NULL) { 1418 return u; 1419 } 1420 } 1421 } 1422 } 1423 1424 return this; // No identity 1425 } 1426 1427 //-----------------------------unique_input------------------------------------ 1428 // Find the unique value, discounting top, self-loops, and casts. 1429 // Return top if there are no inputs, and self if there are multiple. 1430 Node* PhiNode::unique_input(PhaseTransform* phase, bool uncast) { 1431 // 1) One unique direct input, 1432 // or if uncast is true: 1433 // 2) some of the inputs have an intervening ConstraintCast 1434 // 3) an input is a self loop 1435 // 1436 // 1) input or 2) input or 3) input __ 1437 // / \ / \ \ / \ 1438 // \ / | cast phi cast 1439 // phi \ / / \ / 1440 // phi / -- 1441 1442 Node* r = in(0); // RegionNode 1443 Node* input = NULL; // The unique direct input (maybe uncasted = ConstraintCasts removed) 1444 1445 for (uint i = 1, cnt = req(); i < cnt; ++i) { 1446 Node* rc = r->in(i); 1447 if (rc == NULL || phase->type(rc) == Type::TOP) 1448 continue; // ignore unreachable control path 1449 Node* n = in(i); 1450 if (n == NULL) 1451 continue; 1452 Node* un = n; 1453 if (uncast) { 1454 #ifdef ASSERT 1455 Node* m = un->uncast(); 1456 #endif 1457 while (un != NULL && un->req() == 2 && un->is_ConstraintCast()) { 1458 Node* next = un->in(1); 1459 if (phase->type(next)->isa_rawptr() && phase->type(un)->isa_oopptr()) { 1460 // risk exposing raw ptr at safepoint 1461 break; 1462 } 1463 un = next; 1464 } 1465 assert(m == un || un->in(1) == m, "Only expected at CheckCastPP from allocation"); 1466 } 1467 if (un == NULL || un == this || phase->type(un) == Type::TOP) { 1468 continue; // ignore if top, or in(i) and "this" are in a data cycle 1469 } 1470 // Check for a unique input (maybe uncasted) 1471 if (input == NULL) { 1472 input = un; 1473 } else if (input != un) { 1474 input = NodeSentinel; // no unique input 1475 } 1476 } 1477 if (input == NULL) { 1478 return phase->C->top(); // no inputs 1479 } 1480 1481 if (input != NodeSentinel) { 1482 return input; // one unique direct input 1483 } 1484 1485 // Nothing. 1486 return NULL; 1487 } 1488 1489 //------------------------------is_x2logic------------------------------------- 1490 // Check for simple convert-to-boolean pattern 1491 // If:(C Bool) Region:(IfF IfT) Phi:(Region 0 1) 1492 // Convert Phi to an ConvIB. 1493 static Node *is_x2logic( PhaseGVN *phase, PhiNode *phi, int true_path ) { 1494 assert(true_path !=0, "only diamond shape graph expected"); 1495 // Convert the true/false index into an expected 0/1 return. 1496 // Map 2->0 and 1->1. 1497 int flipped = 2-true_path; 1498 1499 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1500 // phi->region->if_proj->ifnode->bool->cmp 1501 Node *region = phi->in(0); 1502 Node *iff = region->in(1)->in(0); 1503 BoolNode *b = (BoolNode*)iff->in(1); 1504 const CmpNode *cmp = (CmpNode*)b->in(1); 1505 1506 Node *zero = phi->in(1); 1507 Node *one = phi->in(2); 1508 const Type *tzero = phase->type( zero ); 1509 const Type *tone = phase->type( one ); 1510 1511 // Check for compare vs 0 1512 const Type *tcmp = phase->type(cmp->in(2)); 1513 if( tcmp != TypeInt::ZERO && tcmp != TypePtr::NULL_PTR ) { 1514 // Allow cmp-vs-1 if the other input is bounded by 0-1 1515 if( !(tcmp == TypeInt::ONE && phase->type(cmp->in(1)) == TypeInt::BOOL) ) 1516 return NULL; 1517 flipped = 1-flipped; // Test is vs 1 instead of 0! 1518 } 1519 1520 // Check for setting zero/one opposite expected 1521 if( tzero == TypeInt::ZERO ) { 1522 if( tone == TypeInt::ONE ) { 1523 } else return NULL; 1524 } else if( tzero == TypeInt::ONE ) { 1525 if( tone == TypeInt::ZERO ) { 1526 flipped = 1-flipped; 1527 } else return NULL; 1528 } else return NULL; 1529 1530 // Check for boolean test backwards 1531 if( b->_test._test == BoolTest::ne ) { 1532 } else if( b->_test._test == BoolTest::eq ) { 1533 flipped = 1-flipped; 1534 } else return NULL; 1535 1536 // Build int->bool conversion 1537 Node *n = new Conv2BNode(cmp->in(1)); 1538 if( flipped ) 1539 n = new XorINode( phase->transform(n), phase->intcon(1) ); 1540 1541 return n; 1542 } 1543 1544 //------------------------------is_cond_add------------------------------------ 1545 // Check for simple conditional add pattern: "(P < Q) ? X+Y : X;" 1546 // To be profitable the control flow has to disappear; there can be no other 1547 // values merging here. We replace the test-and-branch with: 1548 // "(sgn(P-Q))&Y) + X". Basically, convert "(P < Q)" into 0 or -1 by 1549 // moving the carry bit from (P-Q) into a register with 'sbb EAX,EAX'. 1550 // Then convert Y to 0-or-Y and finally add. 1551 // This is a key transform for SpecJava _201_compress. 1552 static Node* is_cond_add(PhaseGVN *phase, PhiNode *phi, int true_path) { 1553 assert(true_path !=0, "only diamond shape graph expected"); 1554 1555 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1556 // phi->region->if_proj->ifnode->bool->cmp 1557 RegionNode *region = (RegionNode*)phi->in(0); 1558 Node *iff = region->in(1)->in(0); 1559 BoolNode* b = iff->in(1)->as_Bool(); 1560 const CmpNode *cmp = (CmpNode*)b->in(1); 1561 1562 // Make sure only merging this one phi here 1563 if (region->has_unique_phi() != phi) return NULL; 1564 1565 // Make sure each arm of the diamond has exactly one output, which we assume 1566 // is the region. Otherwise, the control flow won't disappear. 1567 if (region->in(1)->outcnt() != 1) return NULL; 1568 if (region->in(2)->outcnt() != 1) return NULL; 1569 1570 // Check for "(P < Q)" of type signed int 1571 if (b->_test._test != BoolTest::lt) return NULL; 1572 if (cmp->Opcode() != Op_CmpI) return NULL; 1573 1574 Node *p = cmp->in(1); 1575 Node *q = cmp->in(2); 1576 Node *n1 = phi->in( true_path); 1577 Node *n2 = phi->in(3-true_path); 1578 1579 int op = n1->Opcode(); 1580 if( op != Op_AddI // Need zero as additive identity 1581 /*&&op != Op_SubI && 1582 op != Op_AddP && 1583 op != Op_XorI && 1584 op != Op_OrI*/ ) 1585 return NULL; 1586 1587 Node *x = n2; 1588 Node *y = NULL; 1589 if( x == n1->in(1) ) { 1590 y = n1->in(2); 1591 } else if( x == n1->in(2) ) { 1592 y = n1->in(1); 1593 } else return NULL; 1594 1595 // Not so profitable if compare and add are constants 1596 if( q->is_Con() && phase->type(q) != TypeInt::ZERO && y->is_Con() ) 1597 return NULL; 1598 1599 Node *cmplt = phase->transform( new CmpLTMaskNode(p,q) ); 1600 Node *j_and = phase->transform( new AndINode(cmplt,y) ); 1601 return new AddINode(j_and,x); 1602 } 1603 1604 //------------------------------is_absolute------------------------------------ 1605 // Check for absolute value. 1606 static Node* is_absolute( PhaseGVN *phase, PhiNode *phi_root, int true_path) { 1607 assert(true_path !=0, "only diamond shape graph expected"); 1608 1609 int cmp_zero_idx = 0; // Index of compare input where to look for zero 1610 int phi_x_idx = 0; // Index of phi input where to find naked x 1611 1612 // ABS ends with the merge of 2 control flow paths. 1613 // Find the false path from the true path. With only 2 inputs, 3 - x works nicely. 1614 int false_path = 3 - true_path; 1615 1616 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1617 // phi->region->if_proj->ifnode->bool->cmp 1618 BoolNode *bol = phi_root->in(0)->in(1)->in(0)->in(1)->as_Bool(); 1619 Node *cmp = bol->in(1); 1620 1621 // Check bool sense 1622 if (cmp->Opcode() == Op_CmpF || cmp->Opcode() == Op_CmpD) { 1623 switch (bol->_test._test) { 1624 case BoolTest::lt: cmp_zero_idx = 1; phi_x_idx = true_path; break; 1625 case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break; 1626 case BoolTest::gt: cmp_zero_idx = 2; phi_x_idx = true_path; break; 1627 case BoolTest::ge: cmp_zero_idx = 1; phi_x_idx = false_path; break; 1628 default: return NULL; break; 1629 } 1630 } else if (cmp->Opcode() == Op_CmpI || cmp->Opcode() == Op_CmpL) { 1631 switch (bol->_test._test) { 1632 case BoolTest::lt: 1633 case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break; 1634 case BoolTest::gt: 1635 case BoolTest::ge: cmp_zero_idx = 2; phi_x_idx = true_path; break; 1636 default: return NULL; break; 1637 } 1638 } 1639 1640 // Test is next 1641 const Type *tzero = NULL; 1642 switch (cmp->Opcode()) { 1643 case Op_CmpI: tzero = TypeInt::ZERO; break; // Integer ABS 1644 case Op_CmpL: tzero = TypeLong::ZERO; break; // Long ABS 1645 case Op_CmpF: tzero = TypeF::ZERO; break; // Float ABS 1646 case Op_CmpD: tzero = TypeD::ZERO; break; // Double ABS 1647 default: return NULL; 1648 } 1649 1650 // Find zero input of compare; the other input is being abs'd 1651 Node *x = NULL; 1652 bool flip = false; 1653 if( phase->type(cmp->in(cmp_zero_idx)) == tzero ) { 1654 x = cmp->in(3 - cmp_zero_idx); 1655 } else if( phase->type(cmp->in(3 - cmp_zero_idx)) == tzero ) { 1656 // The test is inverted, we should invert the result... 1657 x = cmp->in(cmp_zero_idx); 1658 flip = true; 1659 } else { 1660 return NULL; 1661 } 1662 1663 // Next get the 2 pieces being selected, one is the original value 1664 // and the other is the negated value. 1665 if( phi_root->in(phi_x_idx) != x ) return NULL; 1666 1667 // Check other phi input for subtract node 1668 Node *sub = phi_root->in(3 - phi_x_idx); 1669 1670 bool is_sub = sub->Opcode() == Op_SubF || sub->Opcode() == Op_SubD || 1671 sub->Opcode() == Op_SubI || sub->Opcode() == Op_SubL; 1672 1673 // Allow only Sub(0,X) and fail out for all others; Neg is not OK 1674 if (!is_sub || phase->type(sub->in(1)) != tzero || sub->in(2) != x) return NULL; 1675 1676 if (tzero == TypeF::ZERO) { 1677 x = new AbsFNode(x); 1678 if (flip) { 1679 x = new SubFNode(sub->in(1), phase->transform(x)); 1680 } 1681 } else if (tzero == TypeD::ZERO) { 1682 x = new AbsDNode(x); 1683 if (flip) { 1684 x = new SubDNode(sub->in(1), phase->transform(x)); 1685 } 1686 } else if (tzero == TypeInt::ZERO && Matcher::match_rule_supported(Op_AbsI)) { 1687 x = new AbsINode(x); 1688 if (flip) { 1689 x = new SubINode(sub->in(1), phase->transform(x)); 1690 } 1691 } else if (tzero == TypeLong::ZERO && Matcher::match_rule_supported(Op_AbsL)) { 1692 x = new AbsLNode(x); 1693 if (flip) { 1694 x = new SubLNode(sub->in(1), phase->transform(x)); 1695 } 1696 } else return NULL; 1697 1698 return x; 1699 } 1700 1701 //------------------------------split_once------------------------------------- 1702 // Helper for split_flow_path 1703 static void split_once(PhaseIterGVN *igvn, Node *phi, Node *val, Node *n, Node *newn) { 1704 igvn->hash_delete(n); // Remove from hash before hacking edges 1705 1706 uint j = 1; 1707 for (uint i = phi->req()-1; i > 0; i--) { 1708 if (phi->in(i) == val) { // Found a path with val? 1709 // Add to NEW Region/Phi, no DU info 1710 newn->set_req( j++, n->in(i) ); 1711 // Remove from OLD Region/Phi 1712 n->del_req(i); 1713 } 1714 } 1715 1716 // Register the new node but do not transform it. Cannot transform until the 1717 // entire Region/Phi conglomerate has been hacked as a single huge transform. 1718 igvn->register_new_node_with_optimizer( newn ); 1719 1720 // Now I can point to the new node. 1721 n->add_req(newn); 1722 igvn->_worklist.push(n); 1723 } 1724 1725 //------------------------------split_flow_path-------------------------------- 1726 // Check for merging identical values and split flow paths 1727 static Node* split_flow_path(PhaseGVN *phase, PhiNode *phi) { 1728 BasicType bt = phi->type()->basic_type(); 1729 if( bt == T_ILLEGAL || type2size[bt] <= 0 ) 1730 return NULL; // Bail out on funny non-value stuff 1731 if( phi->req() <= 3 ) // Need at least 2 matched inputs and a 1732 return NULL; // third unequal input to be worth doing 1733 1734 // Scan for a constant 1735 uint i; 1736 for( i = 1; i < phi->req()-1; i++ ) { 1737 Node *n = phi->in(i); 1738 if( !n ) return NULL; 1739 if( phase->type(n) == Type::TOP ) return NULL; 1740 if( n->Opcode() == Op_ConP || n->Opcode() == Op_ConN || n->Opcode() == Op_ConNKlass ) 1741 break; 1742 } 1743 if( i >= phi->req() ) // Only split for constants 1744 return NULL; 1745 1746 Node *val = phi->in(i); // Constant to split for 1747 uint hit = 0; // Number of times it occurs 1748 Node *r = phi->region(); 1749 1750 for( ; i < phi->req(); i++ ){ // Count occurrences of constant 1751 Node *n = phi->in(i); 1752 if( !n ) return NULL; 1753 if( phase->type(n) == Type::TOP ) return NULL; 1754 if( phi->in(i) == val ) { 1755 hit++; 1756 if (PhaseIdealLoop::find_predicate(r->in(i)) != NULL) { 1757 return NULL; // don't split loop entry path 1758 } 1759 } 1760 } 1761 1762 if( hit <= 1 || // Make sure we find 2 or more 1763 hit == phi->req()-1 ) // and not ALL the same value 1764 return NULL; 1765 1766 // Now start splitting out the flow paths that merge the same value. 1767 // Split first the RegionNode. 1768 PhaseIterGVN *igvn = phase->is_IterGVN(); 1769 RegionNode *newr = new RegionNode(hit+1); 1770 split_once(igvn, phi, val, r, newr); 1771 1772 // Now split all other Phis than this one 1773 for (DUIterator_Fast kmax, k = r->fast_outs(kmax); k < kmax; k++) { 1774 Node* phi2 = r->fast_out(k); 1775 if( phi2->is_Phi() && phi2->as_Phi() != phi ) { 1776 PhiNode *newphi = PhiNode::make_blank(newr, phi2); 1777 split_once(igvn, phi, val, phi2, newphi); 1778 } 1779 } 1780 1781 // Clean up this guy 1782 igvn->hash_delete(phi); 1783 for( i = phi->req()-1; i > 0; i-- ) { 1784 if( phi->in(i) == val ) { 1785 phi->del_req(i); 1786 } 1787 } 1788 phi->add_req(val); 1789 1790 return phi; 1791 } 1792 1793 //============================================================================= 1794 //------------------------------simple_data_loop_check------------------------- 1795 // Try to determining if the phi node in a simple safe/unsafe data loop. 1796 // Returns: 1797 // enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop }; 1798 // Safe - safe case when the phi and it's inputs reference only safe data 1799 // nodes; 1800 // Unsafe - the phi and it's inputs reference unsafe data nodes but there 1801 // is no reference back to the phi - need a graph walk 1802 // to determine if it is in a loop; 1803 // UnsafeLoop - unsafe case when the phi references itself directly or through 1804 // unsafe data node. 1805 // Note: a safe data node is a node which could/never reference itself during 1806 // GVN transformations. For now it is Con, Proj, Phi, CastPP, CheckCastPP. 1807 // I mark Phi nodes as safe node not only because they can reference itself 1808 // but also to prevent mistaking the fallthrough case inside an outer loop 1809 // as dead loop when the phi references itself through an other phi. 1810 PhiNode::LoopSafety PhiNode::simple_data_loop_check(Node *in) const { 1811 // It is unsafe loop if the phi node references itself directly. 1812 if (in == (Node*)this) 1813 return UnsafeLoop; // Unsafe loop 1814 // Unsafe loop if the phi node references itself through an unsafe data node. 1815 // Exclude cases with null inputs or data nodes which could reference 1816 // itself (safe for dead loops). 1817 if (in != NULL && !in->is_dead_loop_safe()) { 1818 // Check inputs of phi's inputs also. 1819 // It is much less expensive then full graph walk. 1820 uint cnt = in->req(); 1821 uint i = (in->is_Proj() && !in->is_CFG()) ? 0 : 1; 1822 for (; i < cnt; ++i) { 1823 Node* m = in->in(i); 1824 if (m == (Node*)this) 1825 return UnsafeLoop; // Unsafe loop 1826 if (m != NULL && !m->is_dead_loop_safe()) { 1827 // Check the most common case (about 30% of all cases): 1828 // phi->Load/Store->AddP->(ConP ConP Con)/(Parm Parm Con). 1829 Node *m1 = (m->is_AddP() && m->req() > 3) ? m->in(1) : NULL; 1830 if (m1 == (Node*)this) 1831 return UnsafeLoop; // Unsafe loop 1832 if (m1 != NULL && m1 == m->in(2) && 1833 m1->is_dead_loop_safe() && m->in(3)->is_Con()) { 1834 continue; // Safe case 1835 } 1836 // The phi references an unsafe node - need full analysis. 1837 return Unsafe; 1838 } 1839 } 1840 } 1841 return Safe; // Safe case - we can optimize the phi node. 1842 } 1843 1844 //------------------------------is_unsafe_data_reference----------------------- 1845 // If phi can be reached through the data input - it is data loop. 1846 bool PhiNode::is_unsafe_data_reference(Node *in) const { 1847 assert(req() > 1, ""); 1848 // First, check simple cases when phi references itself directly or 1849 // through an other node. 1850 LoopSafety safety = simple_data_loop_check(in); 1851 if (safety == UnsafeLoop) 1852 return true; // phi references itself - unsafe loop 1853 else if (safety == Safe) 1854 return false; // Safe case - phi could be replaced with the unique input. 1855 1856 // Unsafe case when we should go through data graph to determine 1857 // if the phi references itself. 1858 1859 ResourceMark rm; 1860 1861 Node_List nstack; 1862 VectorSet visited; 1863 1864 nstack.push(in); // Start with unique input. 1865 visited.set(in->_idx); 1866 while (nstack.size() != 0) { 1867 Node* n = nstack.pop(); 1868 uint cnt = n->req(); 1869 uint i = (n->is_Proj() && !n->is_CFG()) ? 0 : 1; 1870 for (; i < cnt; i++) { 1871 Node* m = n->in(i); 1872 if (m == (Node*)this) { 1873 return true; // Data loop 1874 } 1875 if (m != NULL && !m->is_dead_loop_safe()) { // Only look for unsafe cases. 1876 if (!visited.test_set(m->_idx)) 1877 nstack.push(m); 1878 } 1879 } 1880 } 1881 return false; // The phi is not reachable from its inputs 1882 } 1883 1884 // Is this Phi's region or some inputs to the region enqueued for IGVN 1885 // and so could cause the region to be optimized out? 1886 bool PhiNode::wait_for_region_igvn(PhaseGVN* phase) { 1887 PhaseIterGVN* igvn = phase->is_IterGVN(); 1888 Unique_Node_List& worklist = igvn->_worklist; 1889 bool delay = false; 1890 Node* r = in(0); 1891 for (uint j = 1; j < req(); j++) { 1892 Node* rc = r->in(j); 1893 Node* n = in(j); 1894 if (rc != NULL && 1895 rc->is_Proj()) { 1896 if (worklist.member(rc)) { 1897 delay = true; 1898 } else if (rc->in(0) != NULL && 1899 rc->in(0)->is_If()) { 1900 if (worklist.member(rc->in(0))) { 1901 delay = true; 1902 } else if (rc->in(0)->in(1) != NULL && 1903 rc->in(0)->in(1)->is_Bool()) { 1904 if (worklist.member(rc->in(0)->in(1))) { 1905 delay = true; 1906 } else if (rc->in(0)->in(1)->in(1) != NULL && 1907 rc->in(0)->in(1)->in(1)->is_Cmp()) { 1908 if (worklist.member(rc->in(0)->in(1)->in(1))) { 1909 delay = true; 1910 } 1911 } 1912 } 1913 } 1914 } 1915 } 1916 if (delay) { 1917 worklist.push(this); 1918 } 1919 return delay; 1920 } 1921 1922 // Push inline type input nodes (and null) down through the phi recursively (can handle data loops). 1923 InlineTypeNode* PhiNode::push_inline_types_through(PhaseGVN* phase, bool can_reshape, ciInlineKlass* vk, bool is_init) { 1924 InlineTypeNode* vt = InlineTypeNode::make_null(*phase, vk)->clone_with_phis(phase, in(0), is_init); 1925 if (can_reshape) { 1926 // Replace phi right away to be able to use the inline 1927 // type node when reaching the phi again through data loops. 1928 PhaseIterGVN* igvn = phase->is_IterGVN(); 1929 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 1930 Node* u = fast_out(i); 1931 igvn->rehash_node_delayed(u); 1932 imax -= u->replace_edge(this, vt); 1933 --i; 1934 } 1935 igvn->rehash_node_delayed(this); 1936 assert(outcnt() == 0, "should be dead now"); 1937 } 1938 ResourceMark rm; 1939 Node_List casts; 1940 for (uint i = 1; i < req(); ++i) { 1941 Node* n = in(i); 1942 while (n->is_ConstraintCast()) { 1943 casts.push(n); 1944 n = n->in(1); 1945 } 1946 if (phase->type(n)->is_zero_type()) { 1947 n = InlineTypeNode::make_null(*phase, vk); 1948 } else if (n->is_Phi()) { 1949 assert(can_reshape, "can only handle phis during IGVN"); 1950 n = phase->transform(n->as_Phi()->push_inline_types_through(phase, can_reshape, vk, is_init)); 1951 } 1952 while (casts.size() != 0) { 1953 // Push the cast(s) through the InlineTypeNode 1954 Node* cast = casts.pop()->clone(); 1955 cast->set_req_X(1, n->as_InlineType()->get_oop(), phase); 1956 n = n->clone(); 1957 n->as_InlineType()->set_oop(phase->transform(cast)); 1958 n = phase->transform(n); 1959 } 1960 bool transform = !can_reshape && (i == (req()-1)); // Transform phis on last merge 1961 vt->merge_with(phase, n->as_InlineType(), i, transform); 1962 } 1963 return vt; 1964 } 1965 1966 //------------------------------Ideal------------------------------------------ 1967 // Return a node which is more "ideal" than the current node. Must preserve 1968 // the CFG, but we can still strip out dead paths. 1969 Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1970 Node *r = in(0); // RegionNode 1971 assert(r != NULL && r->is_Region(), "this phi must have a region"); 1972 assert(r->in(0) == NULL || !r->in(0)->is_Root(), "not a specially hidden merge"); 1973 1974 // Note: During parsing, phis are often transformed before their regions. 1975 // This means we have to use type_or_null to defend against untyped regions. 1976 if( phase->type_or_null(r) == Type::TOP ) // Dead code? 1977 return NULL; // No change 1978 1979 Node *top = phase->C->top(); 1980 bool new_phi = (outcnt() == 0); // transforming new Phi 1981 // No change for igvn if new phi is not hooked 1982 if (new_phi && can_reshape) 1983 return NULL; 1984 1985 // The are 2 situations when only one valid phi's input is left 1986 // (in addition to Region input). 1987 // One: region is not loop - replace phi with this input. 1988 // Two: region is loop - replace phi with top since this data path is dead 1989 // and we need to break the dead data loop. 1990 Node* progress = NULL; // Record if any progress made 1991 for( uint j = 1; j < req(); ++j ){ // For all paths in 1992 // Check unreachable control paths 1993 Node* rc = r->in(j); 1994 Node* n = in(j); // Get the input 1995 if (rc == NULL || phase->type(rc) == Type::TOP) { 1996 if (n != top) { // Not already top? 1997 PhaseIterGVN *igvn = phase->is_IterGVN(); 1998 if (can_reshape && igvn != NULL) { 1999 igvn->_worklist.push(r); 2000 } 2001 // Nuke it down 2002 set_req_X(j, top, phase); 2003 progress = this; // Record progress 2004 } 2005 } 2006 } 2007 2008 if (can_reshape && outcnt() == 0) { 2009 // set_req() above may kill outputs if Phi is referenced 2010 // only by itself on the dead (top) control path. 2011 return top; 2012 } 2013 2014 bool uncasted = false; 2015 Node* uin = unique_input(phase, false); 2016 if (uin == NULL && can_reshape && 2017 // If there is a chance that the region can be optimized out do 2018 // not add a cast node that we can't remove yet. 2019 !wait_for_region_igvn(phase)) { 2020 uncasted = true; 2021 uin = unique_input(phase, true); 2022 } 2023 if (uin == top) { // Simplest case: no alive inputs. 2024 if (can_reshape) // IGVN transformation 2025 return top; 2026 else 2027 return NULL; // Identity will return TOP 2028 } else if (uin != NULL) { 2029 // Only one not-NULL unique input path is left. 2030 // Determine if this input is backedge of a loop. 2031 // (Skip new phis which have no uses and dead regions). 2032 if (outcnt() > 0 && r->in(0) != NULL) { 2033 if (is_data_loop(r->as_Region(), uin, phase)) { 2034 // Break this data loop to avoid creation of a dead loop. 2035 if (can_reshape) { 2036 return top; 2037 } else { 2038 // We can't return top if we are in Parse phase - cut inputs only 2039 // let Identity to handle the case. 2040 replace_edge(uin, top, phase); 2041 return NULL; 2042 } 2043 } 2044 } 2045 2046 if (uncasted) { 2047 // Add cast nodes between the phi to be removed and its unique input. 2048 // Wait until after parsing for the type information to propagate from the casts. 2049 assert(can_reshape, "Invalid during parsing"); 2050 const Type* phi_type = bottom_type(); 2051 // Add casts to carry the control dependency of the Phi that is 2052 // going away 2053 Node* cast = NULL; 2054 if (phi_type->isa_ptr()) { 2055 const Type* uin_type = phase->type(uin); 2056 if (!phi_type->isa_oopptr() && !uin_type->isa_oopptr()) { 2057 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, phi_type, ConstraintCastNode::StrongDependency); 2058 } else { 2059 // Use a CastPP for a cast to not null and a CheckCastPP for 2060 // a cast to a new klass (and both if both null-ness and 2061 // klass change). 2062 2063 // If the type of phi is not null but the type of uin may be 2064 // null, uin's type must be casted to not null 2065 if (phi_type->join(TypePtr::NOTNULL) == phi_type->remove_speculative() && 2066 uin_type->join(TypePtr::NOTNULL) != uin_type->remove_speculative()) { 2067 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, TypePtr::NOTNULL, ConstraintCastNode::StrongDependency); 2068 } 2069 2070 // If the type of phi and uin, both casted to not null, 2071 // differ the klass of uin must be (check)cast'ed to match 2072 // that of phi 2073 if (phi_type->join_speculative(TypePtr::NOTNULL) != uin_type->join_speculative(TypePtr::NOTNULL)) { 2074 Node* n = uin; 2075 if (cast != NULL) { 2076 cast = phase->transform(cast); 2077 n = cast; 2078 } 2079 cast = ConstraintCastNode::make_cast(Op_CheckCastPP, r, n, phi_type, ConstraintCastNode::StrongDependency); 2080 } 2081 if (cast == NULL) { 2082 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, phi_type, ConstraintCastNode::StrongDependency); 2083 } 2084 } 2085 } else { 2086 cast = ConstraintCastNode::make_cast_for_type(r, uin, phi_type, ConstraintCastNode::StrongDependency); 2087 } 2088 assert(cast != NULL, "cast should be set"); 2089 cast = phase->transform(cast); 2090 // set all inputs to the new cast(s) so the Phi is removed by Identity 2091 PhaseIterGVN* igvn = phase->is_IterGVN(); 2092 for (uint i = 1; i < req(); i++) { 2093 set_req_X(i, cast, igvn); 2094 } 2095 uin = cast; 2096 } 2097 2098 // One unique input. 2099 debug_only(Node* ident = Identity(phase)); 2100 // The unique input must eventually be detected by the Identity call. 2101 #ifdef ASSERT 2102 if (ident != uin && !ident->is_top()) { 2103 // print this output before failing assert 2104 r->dump(3); 2105 this->dump(3); 2106 ident->dump(); 2107 uin->dump(); 2108 } 2109 #endif 2110 assert(ident == uin || ident->is_top(), "Identity must clean this up"); 2111 return NULL; 2112 } 2113 2114 Node* opt = NULL; 2115 int true_path = is_diamond_phi(); 2116 if (true_path != 0 && 2117 // If one of the diamond's branch is in the process of dying then, the Phi's input for that branch might transform 2118 // to top. If that happens replacing the Phi with an operation that consumes the Phi's inputs will cause the Phi 2119 // to be replaced by top. To prevent that, delay the transformation until the branch has a chance to be removed. 2120 !(can_reshape && wait_for_region_igvn(phase))) { 2121 // Check for CMove'ing identity. If it would be unsafe, 2122 // handle it here. In the safe case, let Identity handle it. 2123 Node* unsafe_id = is_cmove_id(phase, true_path); 2124 if( unsafe_id != NULL && is_unsafe_data_reference(unsafe_id) ) 2125 opt = unsafe_id; 2126 2127 // Check for simple convert-to-boolean pattern 2128 if( opt == NULL ) 2129 opt = is_x2logic(phase, this, true_path); 2130 2131 // Check for absolute value 2132 if( opt == NULL ) 2133 opt = is_absolute(phase, this, true_path); 2134 2135 // Check for conditional add 2136 if( opt == NULL && can_reshape ) 2137 opt = is_cond_add(phase, this, true_path); 2138 2139 // These 4 optimizations could subsume the phi: 2140 // have to check for a dead data loop creation. 2141 if( opt != NULL ) { 2142 if( opt == unsafe_id || is_unsafe_data_reference(opt) ) { 2143 // Found dead loop. 2144 if( can_reshape ) 2145 return top; 2146 // We can't return top if we are in Parse phase - cut inputs only 2147 // to stop further optimizations for this phi. Identity will return TOP. 2148 assert(req() == 3, "only diamond merge phi here"); 2149 set_req(1, top); 2150 set_req(2, top); 2151 return NULL; 2152 } else { 2153 return opt; 2154 } 2155 } 2156 } 2157 2158 // Check for merging identical values and split flow paths 2159 if (can_reshape) { 2160 opt = split_flow_path(phase, this); 2161 // This optimization only modifies phi - don't need to check for dead loop. 2162 assert(opt == NULL || opt == this, "do not elide phi"); 2163 if (opt != NULL) return opt; 2164 } 2165 2166 if (in(1) != NULL && in(1)->Opcode() == Op_AddP && can_reshape) { 2167 // Try to undo Phi of AddP: 2168 // (Phi (AddP base address offset) (AddP base2 address2 offset2)) 2169 // becomes: 2170 // newbase := (Phi base base2) 2171 // newaddress := (Phi address address2) 2172 // newoffset := (Phi offset offset2) 2173 // (AddP newbase newaddress newoffset) 2174 // 2175 // This occurs as a result of unsuccessful split_thru_phi and 2176 // interferes with taking advantage of addressing modes. See the 2177 // clone_shift_expressions code in matcher.cpp 2178 Node* addp = in(1); 2179 Node* base = addp->in(AddPNode::Base); 2180 Node* address = addp->in(AddPNode::Address); 2181 Node* offset = addp->in(AddPNode::Offset); 2182 if (base != NULL && address != NULL && offset != NULL && 2183 !base->is_top() && !address->is_top() && !offset->is_top()) { 2184 const Type* base_type = base->bottom_type(); 2185 const Type* address_type = address->bottom_type(); 2186 // make sure that all the inputs are similar to the first one, 2187 // i.e. AddP with base == address and same offset as first AddP 2188 bool doit = true; 2189 for (uint i = 2; i < req(); i++) { 2190 if (in(i) == NULL || 2191 in(i)->Opcode() != Op_AddP || 2192 in(i)->in(AddPNode::Base) == NULL || 2193 in(i)->in(AddPNode::Address) == NULL || 2194 in(i)->in(AddPNode::Offset) == NULL || 2195 in(i)->in(AddPNode::Base)->is_top() || 2196 in(i)->in(AddPNode::Address)->is_top() || 2197 in(i)->in(AddPNode::Offset)->is_top()) { 2198 doit = false; 2199 break; 2200 } 2201 if (in(i)->in(AddPNode::Base) != base) { 2202 base = NULL; 2203 } 2204 if (in(i)->in(AddPNode::Offset) != offset) { 2205 offset = NULL; 2206 } 2207 if (in(i)->in(AddPNode::Address) != address) { 2208 address = NULL; 2209 } 2210 // Accumulate type for resulting Phi 2211 base_type = base_type->meet_speculative(in(i)->in(AddPNode::Base)->bottom_type()); 2212 address_type = address_type->meet_speculative(in(i)->in(AddPNode::Address)->bottom_type()); 2213 } 2214 if (doit && base == NULL) { 2215 // Check for neighboring AddP nodes in a tree. 2216 // If they have a base, use that it. 2217 for (DUIterator_Fast kmax, k = this->fast_outs(kmax); k < kmax; k++) { 2218 Node* u = this->fast_out(k); 2219 if (u->is_AddP()) { 2220 Node* base2 = u->in(AddPNode::Base); 2221 if (base2 != NULL && !base2->is_top()) { 2222 if (base == NULL) 2223 base = base2; 2224 else if (base != base2) 2225 { doit = false; break; } 2226 } 2227 } 2228 } 2229 } 2230 if (doit) { 2231 if (base == NULL) { 2232 base = new PhiNode(in(0), base_type, NULL); 2233 for (uint i = 1; i < req(); i++) { 2234 base->init_req(i, in(i)->in(AddPNode::Base)); 2235 } 2236 phase->is_IterGVN()->register_new_node_with_optimizer(base); 2237 } 2238 if (address == NULL) { 2239 address = new PhiNode(in(0), address_type, NULL); 2240 for (uint i = 1; i < req(); i++) { 2241 address->init_req(i, in(i)->in(AddPNode::Address)); 2242 } 2243 phase->is_IterGVN()->register_new_node_with_optimizer(address); 2244 } 2245 if (offset == NULL) { 2246 offset = new PhiNode(in(0), TypeX_X, NULL); 2247 for (uint i = 1; i < req(); i++) { 2248 offset->init_req(i, in(i)->in(AddPNode::Offset)); 2249 } 2250 phase->is_IterGVN()->register_new_node_with_optimizer(offset); 2251 } 2252 return new AddPNode(base, address, offset); 2253 } 2254 } 2255 } 2256 2257 // Split phis through memory merges, so that the memory merges will go away. 2258 // Piggy-back this transformation on the search for a unique input.... 2259 // It will be as if the merged memory is the unique value of the phi. 2260 // (Do not attempt this optimization unless parsing is complete. 2261 // It would make the parser's memory-merge logic sick.) 2262 // (MergeMemNode is not dead_loop_safe - need to check for dead loop.) 2263 if (progress == NULL && can_reshape && type() == Type::MEMORY) { 2264 // see if this phi should be sliced 2265 uint merge_width = 0; 2266 bool saw_self = false; 2267 // TODO revisit this with JDK-8247216 2268 bool mergemem_only = true; 2269 for( uint i=1; i<req(); ++i ) {// For all paths in 2270 Node *ii = in(i); 2271 // TOP inputs should not be counted as safe inputs because if the 2272 // Phi references itself through all other inputs then splitting the 2273 // Phi through memory merges would create dead loop at later stage. 2274 if (ii == top) { 2275 return NULL; // Delay optimization until graph is cleaned. 2276 } 2277 if (ii->is_MergeMem()) { 2278 MergeMemNode* n = ii->as_MergeMem(); 2279 merge_width = MAX2(merge_width, n->req()); 2280 saw_self = saw_self || (n->base_memory() == this); 2281 } else { 2282 mergemem_only = false; 2283 } 2284 } 2285 2286 // This restriction is temporarily necessary to ensure termination: 2287 if (!mergemem_only && !saw_self && adr_type() == TypePtr::BOTTOM) merge_width = 0; 2288 2289 if (merge_width > Compile::AliasIdxRaw) { 2290 // found at least one non-empty MergeMem 2291 const TypePtr* at = adr_type(); 2292 if (at != TypePtr::BOTTOM) { 2293 // Patch the existing phi to select an input from the merge: 2294 // Phi:AT1(...MergeMem(m0, m1, m2)...) into 2295 // Phi:AT1(...m1...) 2296 int alias_idx = phase->C->get_alias_index(at); 2297 for (uint i=1; i<req(); ++i) { 2298 Node *ii = in(i); 2299 if (ii->is_MergeMem()) { 2300 MergeMemNode* n = ii->as_MergeMem(); 2301 // compress paths and change unreachable cycles to TOP 2302 // If not, we can update the input infinitely along a MergeMem cycle 2303 // Equivalent code is in MemNode::Ideal_common 2304 Node *m = phase->transform(n); 2305 if (outcnt() == 0) { // Above transform() may kill us! 2306 return top; 2307 } 2308 // If transformed to a MergeMem, get the desired slice 2309 // Otherwise the returned node represents memory for every slice 2310 Node *new_mem = (m->is_MergeMem()) ? 2311 m->as_MergeMem()->memory_at(alias_idx) : m; 2312 // Update input if it is progress over what we have now 2313 if (new_mem != ii) { 2314 set_req_X(i, new_mem, phase->is_IterGVN()); 2315 progress = this; 2316 } 2317 } 2318 } 2319 } else { 2320 // We know that at least one MergeMem->base_memory() == this 2321 // (saw_self == true). If all other inputs also references this phi 2322 // (directly or through data nodes) - it is a dead loop. 2323 bool saw_safe_input = false; 2324 for (uint j = 1; j < req(); ++j) { 2325 Node* n = in(j); 2326 if (n->is_MergeMem()) { 2327 MergeMemNode* mm = n->as_MergeMem(); 2328 if (mm->base_memory() == this || mm->base_memory() == mm->empty_memory()) { 2329 // Skip this input if it references back to this phi or if the memory path is dead 2330 continue; 2331 } 2332 } 2333 if (!is_unsafe_data_reference(n)) { 2334 saw_safe_input = true; // found safe input 2335 break; 2336 } 2337 } 2338 if (!saw_safe_input) { 2339 // There is a dead loop: All inputs are either dead or reference back to this phi 2340 return top; 2341 } 2342 2343 // Phi(...MergeMem(m0, m1:AT1, m2:AT2)...) into 2344 // MergeMem(Phi(...m0...), Phi:AT1(...m1...), Phi:AT2(...m2...)) 2345 PhaseIterGVN* igvn = phase->is_IterGVN(); 2346 assert(igvn != NULL, "sanity check"); 2347 Node* hook = new Node(1); 2348 PhiNode* new_base = (PhiNode*) clone(); 2349 // Must eagerly register phis, since they participate in loops. 2350 igvn->register_new_node_with_optimizer(new_base); 2351 hook->add_req(new_base); 2352 2353 MergeMemNode* result = MergeMemNode::make(new_base); 2354 for (uint i = 1; i < req(); ++i) { 2355 Node *ii = in(i); 2356 if (ii->is_MergeMem()) { 2357 MergeMemNode* n = ii->as_MergeMem(); 2358 if (igvn) { 2359 // TODO revisit this with JDK-8247216 2360 // Put 'n' on the worklist because it might be modified by MergeMemStream::iteration_setup 2361 igvn->_worklist.push(n); 2362 } 2363 for (MergeMemStream mms(result, n); mms.next_non_empty2(); ) { 2364 // If we have not seen this slice yet, make a phi for it. 2365 bool made_new_phi = false; 2366 if (mms.is_empty()) { 2367 Node* new_phi = new_base->slice_memory(mms.adr_type(phase->C)); 2368 made_new_phi = true; 2369 igvn->register_new_node_with_optimizer(new_phi); 2370 hook->add_req(new_phi); 2371 mms.set_memory(new_phi); 2372 } 2373 Node* phi = mms.memory(); 2374 assert(made_new_phi || phi->in(i) == n, "replace the i-th merge by a slice"); 2375 phi->set_req(i, mms.memory2()); 2376 } 2377 } 2378 } 2379 // Distribute all self-loops. 2380 { // (Extra braces to hide mms.) 2381 for (MergeMemStream mms(result); mms.next_non_empty(); ) { 2382 Node* phi = mms.memory(); 2383 for (uint i = 1; i < req(); ++i) { 2384 if (phi->in(i) == this) phi->set_req(i, phi); 2385 } 2386 } 2387 } 2388 // Already replace this phi node to cut it off from the graph to not interfere in dead loop checks during the 2389 // transformations of the new phi nodes below. Otherwise, we could wrongly conclude that there is no dead loop 2390 // because we are finding this phi node again. Also set the type of the new MergeMem node in case we are also 2391 // visiting it in the transformations below. 2392 igvn->replace_node(this, result); 2393 igvn->set_type(result, result->bottom_type()); 2394 2395 // now transform the new nodes, and return the mergemem 2396 for (MergeMemStream mms(result); mms.next_non_empty(); ) { 2397 Node* phi = mms.memory(); 2398 mms.set_memory(phase->transform(phi)); 2399 } 2400 hook->destruct(igvn); 2401 // Replace self with the result. 2402 return result; 2403 } 2404 } 2405 // 2406 // Other optimizations on the memory chain 2407 // 2408 const TypePtr* at = adr_type(); 2409 for( uint i=1; i<req(); ++i ) {// For all paths in 2410 Node *ii = in(i); 2411 Node *new_in = MemNode::optimize_memory_chain(ii, at, NULL, phase); 2412 if (ii != new_in ) { 2413 set_req(i, new_in); 2414 progress = this; 2415 } 2416 } 2417 } 2418 2419 #ifdef _LP64 2420 // Push DecodeN/DecodeNKlass down through phi. 2421 // The rest of phi graph will transform by split EncodeP node though phis up. 2422 if ((UseCompressedOops || UseCompressedClassPointers) && can_reshape && progress == NULL) { 2423 bool may_push = true; 2424 bool has_decodeN = false; 2425 bool is_decodeN = false; 2426 for (uint i=1; i<req(); ++i) {// For all paths in 2427 Node *ii = in(i); 2428 if (ii->is_DecodeNarrowPtr() && ii->bottom_type() == bottom_type()) { 2429 // Do optimization if a non dead path exist. 2430 if (ii->in(1)->bottom_type() != Type::TOP) { 2431 has_decodeN = true; 2432 is_decodeN = ii->is_DecodeN(); 2433 } 2434 } else if (!ii->is_Phi()) { 2435 may_push = false; 2436 } 2437 } 2438 2439 if (has_decodeN && may_push) { 2440 PhaseIterGVN *igvn = phase->is_IterGVN(); 2441 // Make narrow type for new phi. 2442 const Type* narrow_t; 2443 if (is_decodeN) { 2444 narrow_t = TypeNarrowOop::make(this->bottom_type()->is_ptr()); 2445 } else { 2446 narrow_t = TypeNarrowKlass::make(this->bottom_type()->is_ptr()); 2447 } 2448 PhiNode* new_phi = new PhiNode(r, narrow_t); 2449 uint orig_cnt = req(); 2450 for (uint i=1; i<req(); ++i) {// For all paths in 2451 Node *ii = in(i); 2452 Node* new_ii = NULL; 2453 if (ii->is_DecodeNarrowPtr()) { 2454 assert(ii->bottom_type() == bottom_type(), "sanity"); 2455 new_ii = ii->in(1); 2456 } else { 2457 assert(ii->is_Phi(), "sanity"); 2458 if (ii->as_Phi() == this) { 2459 new_ii = new_phi; 2460 } else { 2461 if (is_decodeN) { 2462 new_ii = new EncodePNode(ii, narrow_t); 2463 } else { 2464 new_ii = new EncodePKlassNode(ii, narrow_t); 2465 } 2466 igvn->register_new_node_with_optimizer(new_ii); 2467 } 2468 } 2469 new_phi->set_req(i, new_ii); 2470 } 2471 igvn->register_new_node_with_optimizer(new_phi, this); 2472 if (is_decodeN) { 2473 progress = new DecodeNNode(new_phi, bottom_type()); 2474 } else { 2475 progress = new DecodeNKlassNode(new_phi, bottom_type()); 2476 } 2477 } 2478 } 2479 #endif 2480 2481 // Check recursively if inputs are either an inline type, constant null 2482 // or another Phi (including self references through data loops). If so, 2483 // push the inline types down through the phis to enable folding of loads. 2484 if (EnableValhalla && _type->isa_ptr() && req() > 2) { 2485 ResourceMark rm; 2486 Unique_Node_List worklist; 2487 worklist.push(this); 2488 bool can_optimize = true; 2489 ciInlineKlass* vk = NULL; 2490 // true if all IsInit inputs of all InlineType* nodes are true 2491 bool is_init = true; 2492 Node_List casts; 2493 2494 // TODO 8302217 We need to prevent endless pushing through 2495 bool only_phi = (outcnt() != 0); 2496 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 2497 Node* n = fast_out(i); 2498 if (n->is_InlineType() && n->in(1) == this) { 2499 can_optimize = false; 2500 break; 2501 } 2502 if (!n->is_Phi()) { 2503 only_phi = false; 2504 } 2505 } 2506 if (only_phi) { 2507 can_optimize = false; 2508 } 2509 for (uint next = 0; next < worklist.size() && can_optimize; next++) { 2510 Node* phi = worklist.at(next); 2511 for (uint i = 1; i < phi->req() && can_optimize; i++) { 2512 Node* n = phi->in(i); 2513 if (n == NULL) { 2514 can_optimize = false; 2515 break; 2516 } 2517 while (n->is_ConstraintCast()) { 2518 if (n->in(0) != NULL && n->in(0)->is_top()) { 2519 // Will die, don't optimize 2520 can_optimize = false; 2521 break; 2522 } 2523 casts.push(n); 2524 n = n->in(1); 2525 } 2526 const Type* t = phase->type(n); 2527 if (n->is_InlineType() && (vk == NULL || vk == t->inline_klass())) { 2528 vk = (vk == NULL) ? t->inline_klass() : vk; 2529 if (phase->find_int_con(n->as_InlineType()->get_is_init(), 0) != 1) { 2530 is_init = false; 2531 } 2532 } else if (n->is_Phi() && can_reshape && n->bottom_type()->isa_ptr()) { 2533 worklist.push(n); 2534 } else if (t->is_zero_type()) { 2535 is_init = false; 2536 } else { 2537 can_optimize = false; 2538 } 2539 } 2540 } 2541 // Check if cast nodes can be pushed through 2542 const Type* t = Type::get_const_type(vk); 2543 while (casts.size() != 0 && can_optimize && t != NULL) { 2544 Node* cast = casts.pop(); 2545 if (t->filter(cast->bottom_type()) == Type::TOP) { 2546 can_optimize = false; 2547 } 2548 } 2549 if (can_optimize && vk != NULL) { 2550 // TODO 8302217 2551 // assert(!_type->isa_ptr() || _type->maybe_null() || is_init, "Phi not null but a possible null was seen"); 2552 return push_inline_types_through(phase, can_reshape, vk, is_init); 2553 } 2554 } 2555 2556 // Phi (VB ... VB) => VB (Phi ...) (Phi ...) 2557 if (EnableVectorReboxing && can_reshape && progress == NULL && type()->isa_oopptr()) { 2558 progress = merge_through_phi(this, phase->is_IterGVN()); 2559 } 2560 2561 return progress; // Return any progress 2562 } 2563 2564 Node* PhiNode::clone_through_phi(Node* root_phi, const Type* t, uint c, PhaseIterGVN* igvn) { 2565 Node_Stack stack(1); 2566 VectorSet visited; 2567 Node_List node_map; 2568 2569 stack.push(root_phi, 1); // ignore control 2570 visited.set(root_phi->_idx); 2571 2572 Node* new_phi = new PhiNode(root_phi->in(0), t); 2573 node_map.map(root_phi->_idx, new_phi); 2574 2575 while (stack.is_nonempty()) { 2576 Node* n = stack.node(); 2577 uint idx = stack.index(); 2578 assert(n->is_Phi(), "not a phi"); 2579 if (idx < n->req()) { 2580 stack.set_index(idx + 1); 2581 Node* def = n->in(idx); 2582 if (def == NULL) { 2583 continue; // ignore dead path 2584 } else if (def->is_Phi()) { // inner node 2585 Node* new_phi = node_map[n->_idx]; 2586 if (!visited.test_set(def->_idx)) { // not visited yet 2587 node_map.map(def->_idx, new PhiNode(def->in(0), t)); 2588 stack.push(def, 1); // ignore control 2589 } 2590 Node* new_in = node_map[def->_idx]; 2591 new_phi->set_req(idx, new_in); 2592 } else if (def->Opcode() == Op_VectorBox) { // leaf 2593 assert(n->is_Phi(), "not a phi"); 2594 Node* new_phi = node_map[n->_idx]; 2595 new_phi->set_req(idx, def->in(c)); 2596 } else { 2597 assert(false, "not optimizeable"); 2598 return NULL; 2599 } 2600 } else { 2601 Node* new_phi = node_map[n->_idx]; 2602 igvn->register_new_node_with_optimizer(new_phi, n); 2603 stack.pop(); 2604 } 2605 } 2606 return new_phi; 2607 } 2608 2609 Node* PhiNode::merge_through_phi(Node* root_phi, PhaseIterGVN* igvn) { 2610 Node_Stack stack(1); 2611 VectorSet visited; 2612 2613 stack.push(root_phi, 1); // ignore control 2614 visited.set(root_phi->_idx); 2615 2616 VectorBoxNode* cached_vbox = NULL; 2617 while (stack.is_nonempty()) { 2618 Node* n = stack.node(); 2619 uint idx = stack.index(); 2620 if (idx < n->req()) { 2621 stack.set_index(idx + 1); 2622 Node* in = n->in(idx); 2623 if (in == NULL) { 2624 continue; // ignore dead path 2625 } else if (in->isa_Phi()) { 2626 if (!visited.test_set(in->_idx)) { 2627 stack.push(in, 1); // ignore control 2628 } 2629 } else if (in->Opcode() == Op_VectorBox) { 2630 VectorBoxNode* vbox = static_cast<VectorBoxNode*>(in); 2631 if (cached_vbox == NULL) { 2632 cached_vbox = vbox; 2633 } else if (vbox->vec_type() != cached_vbox->vec_type()) { 2634 // TODO: vector type mismatch can be handled with additional reinterpret casts 2635 assert(Type::cmp(vbox->vec_type(), cached_vbox->vec_type()) != 0, "inconsistent"); 2636 return NULL; // not optimizable: vector type mismatch 2637 } else if (vbox->box_type() != cached_vbox->box_type()) { 2638 assert(Type::cmp(vbox->box_type(), cached_vbox->box_type()) != 0, "inconsistent"); 2639 return NULL; // not optimizable: box type mismatch 2640 } 2641 } else { 2642 return NULL; // not optimizable: neither Phi nor VectorBox 2643 } 2644 } else { 2645 stack.pop(); 2646 } 2647 } 2648 2649 assert(cached_vbox != NULL, "sanity"); 2650 const TypeInstPtr* btype = cached_vbox->box_type(); 2651 const TypeVect* vtype = cached_vbox->vec_type(); 2652 Node* new_vbox_phi = clone_through_phi(root_phi, btype, VectorBoxNode::Box, igvn); 2653 Node* new_vect_phi = clone_through_phi(root_phi, vtype, VectorBoxNode::Value, igvn); 2654 return new VectorBoxNode(igvn->C, new_vbox_phi, new_vect_phi, btype, vtype); 2655 } 2656 2657 bool PhiNode::is_data_loop(RegionNode* r, Node* uin, const PhaseGVN* phase) { 2658 // First, take the short cut when we know it is a loop and the EntryControl data path is dead. 2659 // The loop node may only have one input because the entry path was removed in PhaseIdealLoop::Dominators(). 2660 // Then, check if there is a data loop when the phi references itself directly or through other data nodes. 2661 assert(!r->is_Loop() || r->req() <= 3, "Loop node should have 3 or less inputs"); 2662 const bool is_loop = (r->is_Loop() && r->req() == 3); 2663 const Node* top = phase->C->top(); 2664 if (is_loop) { 2665 return !uin->eqv_uncast(in(LoopNode::EntryControl)); 2666 } else { 2667 // We have a data loop either with an unsafe data reference or if a region is unreachable. 2668 return is_unsafe_data_reference(uin) 2669 || (r->req() == 3 && (r->in(1) != top && r->in(2) == top && r->is_unreachable_region(phase))); 2670 } 2671 } 2672 2673 //------------------------------is_tripcount----------------------------------- 2674 bool PhiNode::is_tripcount(BasicType bt) const { 2675 return (in(0) != NULL && in(0)->is_BaseCountedLoop() && 2676 in(0)->as_BaseCountedLoop()->bt() == bt && 2677 in(0)->as_BaseCountedLoop()->phi() == this); 2678 } 2679 2680 //------------------------------out_RegMask------------------------------------ 2681 const RegMask &PhiNode::in_RegMask(uint i) const { 2682 return i ? out_RegMask() : RegMask::Empty; 2683 } 2684 2685 const RegMask &PhiNode::out_RegMask() const { 2686 uint ideal_reg = _type->ideal_reg(); 2687 assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" ); 2688 if( ideal_reg == 0 ) return RegMask::Empty; 2689 assert(ideal_reg != Op_RegFlags, "flags register is not spillable"); 2690 return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]); 2691 } 2692 2693 #ifndef PRODUCT 2694 void PhiNode::dump_spec(outputStream *st) const { 2695 TypeNode::dump_spec(st); 2696 if (is_tripcount(T_INT) || is_tripcount(T_LONG)) { 2697 st->print(" #tripcount"); 2698 } 2699 } 2700 #endif 2701 2702 2703 //============================================================================= 2704 const Type* GotoNode::Value(PhaseGVN* phase) const { 2705 // If the input is reachable, then we are executed. 2706 // If the input is not reachable, then we are not executed. 2707 return phase->type(in(0)); 2708 } 2709 2710 Node* GotoNode::Identity(PhaseGVN* phase) { 2711 return in(0); // Simple copy of incoming control 2712 } 2713 2714 const RegMask &GotoNode::out_RegMask() const { 2715 return RegMask::Empty; 2716 } 2717 2718 //============================================================================= 2719 const RegMask &JumpNode::out_RegMask() const { 2720 return RegMask::Empty; 2721 } 2722 2723 //============================================================================= 2724 const RegMask &JProjNode::out_RegMask() const { 2725 return RegMask::Empty; 2726 } 2727 2728 //============================================================================= 2729 const RegMask &CProjNode::out_RegMask() const { 2730 return RegMask::Empty; 2731 } 2732 2733 2734 2735 //============================================================================= 2736 2737 uint PCTableNode::hash() const { return Node::hash() + _size; } 2738 bool PCTableNode::cmp( const Node &n ) const 2739 { return _size == ((PCTableNode&)n)._size; } 2740 2741 const Type *PCTableNode::bottom_type() const { 2742 const Type** f = TypeTuple::fields(_size); 2743 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; 2744 return TypeTuple::make(_size, f); 2745 } 2746 2747 //------------------------------Value------------------------------------------ 2748 // Compute the type of the PCTableNode. If reachable it is a tuple of 2749 // Control, otherwise the table targets are not reachable 2750 const Type* PCTableNode::Value(PhaseGVN* phase) const { 2751 if( phase->type(in(0)) == Type::CONTROL ) 2752 return bottom_type(); 2753 return Type::TOP; // All paths dead? Then so are we 2754 } 2755 2756 //------------------------------Ideal------------------------------------------ 2757 // Return a node which is more "ideal" than the current node. Strip out 2758 // control copies 2759 Node *PCTableNode::Ideal(PhaseGVN *phase, bool can_reshape) { 2760 return remove_dead_region(phase, can_reshape) ? this : NULL; 2761 } 2762 2763 //============================================================================= 2764 uint JumpProjNode::hash() const { 2765 return Node::hash() + _dest_bci; 2766 } 2767 2768 bool JumpProjNode::cmp( const Node &n ) const { 2769 return ProjNode::cmp(n) && 2770 _dest_bci == ((JumpProjNode&)n)._dest_bci; 2771 } 2772 2773 #ifndef PRODUCT 2774 void JumpProjNode::dump_spec(outputStream *st) const { 2775 ProjNode::dump_spec(st); 2776 st->print("@bci %d ",_dest_bci); 2777 } 2778 2779 void JumpProjNode::dump_compact_spec(outputStream *st) const { 2780 ProjNode::dump_compact_spec(st); 2781 st->print("(%d)%d@%d", _switch_val, _proj_no, _dest_bci); 2782 } 2783 #endif 2784 2785 //============================================================================= 2786 //------------------------------Value------------------------------------------ 2787 // Check for being unreachable, or for coming from a Rethrow. Rethrow's cannot 2788 // have the default "fall_through_index" path. 2789 const Type* CatchNode::Value(PhaseGVN* phase) const { 2790 // Unreachable? Then so are all paths from here. 2791 if( phase->type(in(0)) == Type::TOP ) return Type::TOP; 2792 // First assume all paths are reachable 2793 const Type** f = TypeTuple::fields(_size); 2794 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; 2795 // Identify cases that will always throw an exception 2796 // () rethrow call 2797 // () virtual or interface call with NULL receiver 2798 // () call is a check cast with incompatible arguments 2799 if( in(1)->is_Proj() ) { 2800 Node *i10 = in(1)->in(0); 2801 if( i10->is_Call() ) { 2802 CallNode *call = i10->as_Call(); 2803 // Rethrows always throw exceptions, never return 2804 if (call->entry_point() == OptoRuntime::rethrow_stub()) { 2805 f[CatchProjNode::fall_through_index] = Type::TOP; 2806 } else if (call->is_AllocateArray()) { 2807 Node* klass_node = call->in(AllocateNode::KlassNode); 2808 Node* length = call->in(AllocateNode::ALength); 2809 const Type* length_type = phase->type(length); 2810 const Type* klass_type = phase->type(klass_node); 2811 Node* valid_length_test = call->in(AllocateNode::ValidLengthTest); 2812 const Type* valid_length_test_t = phase->type(valid_length_test); 2813 if (length_type == Type::TOP || klass_type == Type::TOP || valid_length_test_t == Type::TOP || 2814 valid_length_test_t->is_int()->is_con(0)) { 2815 f[CatchProjNode::fall_through_index] = Type::TOP; 2816 } 2817 } else if( call->req() > TypeFunc::Parms ) { 2818 const Type *arg0 = phase->type( call->in(TypeFunc::Parms) ); 2819 // Check for null receiver to virtual or interface calls 2820 if( call->is_CallDynamicJava() && 2821 arg0->higher_equal(TypePtr::NULL_PTR) ) { 2822 f[CatchProjNode::fall_through_index] = Type::TOP; 2823 } 2824 } // End of if not a runtime stub 2825 } // End of if have call above me 2826 } // End of slot 1 is not a projection 2827 return TypeTuple::make(_size, f); 2828 } 2829 2830 //============================================================================= 2831 uint CatchProjNode::hash() const { 2832 return Node::hash() + _handler_bci; 2833 } 2834 2835 2836 bool CatchProjNode::cmp( const Node &n ) const { 2837 return ProjNode::cmp(n) && 2838 _handler_bci == ((CatchProjNode&)n)._handler_bci; 2839 } 2840 2841 2842 //------------------------------Identity--------------------------------------- 2843 // If only 1 target is possible, choose it if it is the main control 2844 Node* CatchProjNode::Identity(PhaseGVN* phase) { 2845 // If my value is control and no other value is, then treat as ID 2846 const TypeTuple *t = phase->type(in(0))->is_tuple(); 2847 if (t->field_at(_con) != Type::CONTROL) return this; 2848 // If we remove the last CatchProj and elide the Catch/CatchProj, then we 2849 // also remove any exception table entry. Thus we must know the call 2850 // feeding the Catch will not really throw an exception. This is ok for 2851 // the main fall-thru control (happens when we know a call can never throw 2852 // an exception) or for "rethrow", because a further optimization will 2853 // yank the rethrow (happens when we inline a function that can throw an 2854 // exception and the caller has no handler). Not legal, e.g., for passing 2855 // a NULL receiver to a v-call, or passing bad types to a slow-check-cast. 2856 // These cases MUST throw an exception via the runtime system, so the VM 2857 // will be looking for a table entry. 2858 Node *proj = in(0)->in(1); // Expect a proj feeding CatchNode 2859 CallNode *call; 2860 if (_con != TypeFunc::Control && // Bail out if not the main control. 2861 !(proj->is_Proj() && // AND NOT a rethrow 2862 proj->in(0)->is_Call() && 2863 (call = proj->in(0)->as_Call()) && 2864 call->entry_point() == OptoRuntime::rethrow_stub())) 2865 return this; 2866 2867 // Search for any other path being control 2868 for (uint i = 0; i < t->cnt(); i++) { 2869 if (i != _con && t->field_at(i) == Type::CONTROL) 2870 return this; 2871 } 2872 // Only my path is possible; I am identity on control to the jump 2873 return in(0)->in(0); 2874 } 2875 2876 2877 #ifndef PRODUCT 2878 void CatchProjNode::dump_spec(outputStream *st) const { 2879 ProjNode::dump_spec(st); 2880 st->print("@bci %d ",_handler_bci); 2881 } 2882 #endif 2883 2884 //============================================================================= 2885 //------------------------------Identity--------------------------------------- 2886 // Check for CreateEx being Identity. 2887 Node* CreateExNode::Identity(PhaseGVN* phase) { 2888 if( phase->type(in(1)) == Type::TOP ) return in(1); 2889 if( phase->type(in(0)) == Type::TOP ) return in(0); 2890 // We only come from CatchProj, unless the CatchProj goes away. 2891 // If the CatchProj is optimized away, then we just carry the 2892 // exception oop through. 2893 2894 // CheckCastPPNode::Ideal() for inline types reuses the exception 2895 // paths of a call to perform an allocation: we can see a Phi here. 2896 if (in(1)->is_Phi()) { 2897 return this; 2898 } 2899 CallNode *call = in(1)->in(0)->as_Call(); 2900 2901 return (in(0)->is_CatchProj() && in(0)->in(0)->is_Catch() && 2902 in(0)->in(0)->in(1) == in(1)) ? this : call->in(TypeFunc::Parms); 2903 } 2904 2905 //============================================================================= 2906 //------------------------------Value------------------------------------------ 2907 // Check for being unreachable. 2908 const Type* NeverBranchNode::Value(PhaseGVN* phase) const { 2909 if (!in(0) || in(0)->is_top()) return Type::TOP; 2910 return bottom_type(); 2911 } 2912 2913 //------------------------------Ideal------------------------------------------ 2914 // Check for no longer being part of a loop 2915 Node *NeverBranchNode::Ideal(PhaseGVN *phase, bool can_reshape) { 2916 if (can_reshape && !in(0)->is_Region()) { 2917 // Dead code elimination can sometimes delete this projection so 2918 // if it's not there, there's nothing to do. 2919 Node* fallthru = proj_out_or_null(0); 2920 if (fallthru != NULL) { 2921 phase->is_IterGVN()->replace_node(fallthru, in(0)); 2922 } 2923 return phase->C->top(); 2924 } 2925 return NULL; 2926 } 2927 2928 #ifndef PRODUCT 2929 void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const { 2930 st->print("%s", Name()); 2931 } 2932 #endif 2933 2934 #ifndef PRODUCT 2935 void BlackholeNode::format(PhaseRegAlloc* ra, outputStream* st) const { 2936 st->print("blackhole "); 2937 bool first = true; 2938 for (uint i = 0; i < req(); i++) { 2939 Node* n = in(i); 2940 if (n != NULL && OptoReg::is_valid(ra->get_reg_first(n))) { 2941 if (first) { 2942 first = false; 2943 } else { 2944 st->print(", "); 2945 } 2946 char buf[128]; 2947 ra->dump_register(n, buf); 2948 st->print("%s", buf); 2949 } 2950 } 2951 st->cr(); 2952 } 2953 #endif 2954