1 /* 2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/systemDictionary.hpp" 27 #include "gc/shared/barrierSet.hpp" 28 #include "gc/shared/c2/barrierSetC2.hpp" 29 #include "memory/allocation.inline.hpp" 30 #include "memory/resourceArea.hpp" 31 #include "oops/objArrayKlass.hpp" 32 #include "opto/addnode.hpp" 33 #include "opto/castnode.hpp" 34 #include "opto/cfgnode.hpp" 35 #include "opto/connode.hpp" 36 #include "opto/convertnode.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/regmask.hpp" 44 #include "opto/runtime.hpp" 45 #include "opto/subnode.hpp" 46 #include "utilities/vmError.hpp" 47 48 // Portions of code courtesy of Clifford Click 49 50 // Optimization - Graph Style 51 52 //============================================================================= 53 //------------------------------Value------------------------------------------ 54 // Compute the type of the RegionNode. 55 const Type* RegionNode::Value(PhaseGVN* phase) const { 56 for( uint i=1; i<req(); ++i ) { // For all paths in 57 Node *n = in(i); // Get Control source 58 if( !n ) continue; // Missing inputs are TOP 59 if( phase->type(n) == Type::CONTROL ) 60 return Type::CONTROL; 61 } 62 return Type::TOP; // All paths dead? Then so are we 63 } 64 65 //------------------------------Identity--------------------------------------- 66 // Check for Region being Identity. 67 Node* RegionNode::Identity(PhaseGVN* phase) { 68 // Cannot have Region be an identity, even if it has only 1 input. 69 // Phi users cannot have their Region input folded away for them, 70 // since they need to select the proper data input 71 return this; 72 } 73 74 //------------------------------merge_region----------------------------------- 75 // If a Region flows into a Region, merge into one big happy merge. This is 76 // hard to do if there is stuff that has to happen 77 static Node *merge_region(RegionNode *region, PhaseGVN *phase) { 78 if( region->Opcode() != Op_Region ) // Do not do to LoopNodes 79 return NULL; 80 Node *progress = NULL; // Progress flag 81 PhaseIterGVN *igvn = phase->is_IterGVN(); 82 83 uint rreq = region->req(); 84 for( uint i = 1; i < rreq; i++ ) { 85 Node *r = region->in(i); 86 if( r && r->Opcode() == Op_Region && // Found a region? 87 r->in(0) == r && // Not already collapsed? 88 r != region && // Avoid stupid situations 89 r->outcnt() == 2 ) { // Self user and 'region' user only? 90 assert(!r->as_Region()->has_phi(), "no phi users"); 91 if( !progress ) { // No progress 92 if (region->has_phi()) { 93 return NULL; // Only flatten if no Phi users 94 // igvn->hash_delete( phi ); 95 } 96 igvn->hash_delete( region ); 97 progress = region; // Making progress 98 } 99 igvn->hash_delete( r ); 100 101 // Append inputs to 'r' onto 'region' 102 for( uint j = 1; j < r->req(); j++ ) { 103 // Move an input from 'r' to 'region' 104 region->add_req(r->in(j)); 105 r->set_req(j, phase->C->top()); 106 // Update phis of 'region' 107 //for( uint k = 0; k < max; k++ ) { 108 // Node *phi = region->out(k); 109 // if( phi->is_Phi() ) { 110 // phi->add_req(phi->in(i)); 111 // } 112 //} 113 114 rreq++; // One more input to Region 115 } // Found a region to merge into Region 116 igvn->_worklist.push(r); 117 // Clobber pointer to the now dead 'r' 118 region->set_req(i, phase->C->top()); 119 } 120 } 121 122 return progress; 123 } 124 125 126 127 //--------------------------------has_phi-------------------------------------- 128 // Helper function: Return any PhiNode that uses this region or NULL 129 PhiNode* RegionNode::has_phi() const { 130 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 131 Node* phi = fast_out(i); 132 if (phi->is_Phi()) { // Check for Phi users 133 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); 134 return phi->as_Phi(); // this one is good enough 135 } 136 } 137 138 return NULL; 139 } 140 141 142 //-----------------------------has_unique_phi---------------------------------- 143 // Helper function: Return the only PhiNode that uses this region or NULL 144 PhiNode* RegionNode::has_unique_phi() const { 145 // Check that only one use is a Phi 146 PhiNode* only_phi = NULL; 147 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 148 Node* phi = fast_out(i); 149 if (phi->is_Phi()) { // Check for Phi users 150 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); 151 if (only_phi == NULL) { 152 only_phi = phi->as_Phi(); 153 } else { 154 return NULL; // multiple phis 155 } 156 } 157 } 158 159 return only_phi; 160 } 161 162 163 //------------------------------check_phi_clipping----------------------------- 164 // Helper function for RegionNode's identification of FP clipping 165 // Check inputs to the Phi 166 static bool check_phi_clipping( PhiNode *phi, ConNode * &min, uint &min_idx, ConNode * &max, uint &max_idx, Node * &val, uint &val_idx ) { 167 min = NULL; 168 max = NULL; 169 val = NULL; 170 min_idx = 0; 171 max_idx = 0; 172 val_idx = 0; 173 uint phi_max = phi->req(); 174 if( phi_max == 4 ) { 175 for( uint j = 1; j < phi_max; ++j ) { 176 Node *n = phi->in(j); 177 int opcode = n->Opcode(); 178 switch( opcode ) { 179 case Op_ConI: 180 { 181 if( min == NULL ) { 182 min = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; 183 min_idx = j; 184 } else { 185 max = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; 186 max_idx = j; 187 if( min->get_int() > max->get_int() ) { 188 // Swap min and max 189 ConNode *temp; 190 uint temp_idx; 191 temp = min; min = max; max = temp; 192 temp_idx = min_idx; min_idx = max_idx; max_idx = temp_idx; 193 } 194 } 195 } 196 break; 197 default: 198 { 199 val = n; 200 val_idx = j; 201 } 202 break; 203 } 204 } 205 } 206 return ( min && max && val && (min->get_int() <= 0) && (max->get_int() >=0) ); 207 } 208 209 210 //------------------------------check_if_clipping------------------------------ 211 // Helper function for RegionNode's identification of FP clipping 212 // Check that inputs to Region come from two IfNodes, 213 // 214 // If 215 // False True 216 // If | 217 // False True | 218 // | | | 219 // RegionNode_inputs 220 // 221 static bool check_if_clipping( const RegionNode *region, IfNode * &bot_if, IfNode * &top_if ) { 222 top_if = NULL; 223 bot_if = NULL; 224 225 // Check control structure above RegionNode for (if ( if ) ) 226 Node *in1 = region->in(1); 227 Node *in2 = region->in(2); 228 Node *in3 = region->in(3); 229 // Check that all inputs are projections 230 if( in1->is_Proj() && in2->is_Proj() && in3->is_Proj() ) { 231 Node *in10 = in1->in(0); 232 Node *in20 = in2->in(0); 233 Node *in30 = in3->in(0); 234 // Check that #1 and #2 are ifTrue and ifFalse from same If 235 if( in10 != NULL && in10->is_If() && 236 in20 != NULL && in20->is_If() && 237 in30 != NULL && in30->is_If() && in10 == in20 && 238 (in1->Opcode() != in2->Opcode()) ) { 239 Node *in100 = in10->in(0); 240 Node *in1000 = (in100 != NULL && in100->is_Proj()) ? in100->in(0) : NULL; 241 // Check that control for in10 comes from other branch of IF from in3 242 if( in1000 != NULL && in1000->is_If() && 243 in30 == in1000 && (in3->Opcode() != in100->Opcode()) ) { 244 // Control pattern checks 245 top_if = (IfNode*)in1000; 246 bot_if = (IfNode*)in10; 247 } 248 } 249 } 250 251 return (top_if != NULL); 252 } 253 254 255 //------------------------------check_convf2i_clipping------------------------- 256 // Helper function for RegionNode's identification of FP clipping 257 // Verify that the value input to the phi comes from "ConvF2I; LShift; RShift" 258 static bool check_convf2i_clipping( PhiNode *phi, uint idx, ConvF2INode * &convf2i, Node *min, Node *max) { 259 convf2i = NULL; 260 261 // Check for the RShiftNode 262 Node *rshift = phi->in(idx); 263 assert( rshift, "Previous checks ensure phi input is present"); 264 if( rshift->Opcode() != Op_RShiftI ) { return false; } 265 266 // Check for the LShiftNode 267 Node *lshift = rshift->in(1); 268 assert( lshift, "Previous checks ensure phi input is present"); 269 if( lshift->Opcode() != Op_LShiftI ) { return false; } 270 271 // Check for the ConvF2INode 272 Node *conv = lshift->in(1); 273 if( conv->Opcode() != Op_ConvF2I ) { return false; } 274 275 // Check that shift amounts are only to get sign bits set after F2I 276 jint max_cutoff = max->get_int(); 277 jint min_cutoff = min->get_int(); 278 jint left_shift = lshift->in(2)->get_int(); 279 jint right_shift = rshift->in(2)->get_int(); 280 jint max_post_shift = nth_bit(BitsPerJavaInteger - left_shift - 1); 281 if( left_shift != right_shift || 282 0 > left_shift || left_shift >= BitsPerJavaInteger || 283 max_post_shift < max_cutoff || 284 max_post_shift < -min_cutoff ) { 285 // Shifts are necessary but current transformation eliminates them 286 return false; 287 } 288 289 // OK to return the result of ConvF2I without shifting 290 convf2i = (ConvF2INode*)conv; 291 return true; 292 } 293 294 295 //------------------------------check_compare_clipping------------------------- 296 // Helper function for RegionNode's identification of FP clipping 297 static bool check_compare_clipping( bool less_than, IfNode *iff, ConNode *limit, Node * & input ) { 298 Node *i1 = iff->in(1); 299 if ( !i1->is_Bool() ) { return false; } 300 BoolNode *bool1 = i1->as_Bool(); 301 if( less_than && bool1->_test._test != BoolTest::le ) { return false; } 302 else if( !less_than && bool1->_test._test != BoolTest::lt ) { return false; } 303 const Node *cmpF = bool1->in(1); 304 if( cmpF->Opcode() != Op_CmpF ) { return false; } 305 // Test that the float value being compared against 306 // is equivalent to the int value used as a limit 307 Node *nodef = cmpF->in(2); 308 if( nodef->Opcode() != Op_ConF ) { return false; } 309 jfloat conf = nodef->getf(); 310 jint coni = limit->get_int(); 311 if( ((int)conf) != coni ) { return false; } 312 input = cmpF->in(1); 313 return true; 314 } 315 316 //------------------------------is_unreachable_region-------------------------- 317 // Find if the Region node is reachable from the root. 318 bool RegionNode::is_unreachable_region(PhaseGVN *phase) const { 319 assert(req() == 2, ""); 320 321 // First, cut the simple case of fallthrough region when NONE of 322 // region's phis references itself directly or through a data node. 323 uint max = outcnt(); 324 uint i; 325 for (i = 0; i < max; i++) { 326 Node* phi = raw_out(i); 327 if (phi != NULL && phi->is_Phi()) { 328 assert(phase->eqv(phi->in(0), this) && phi->req() == 2, ""); 329 if (phi->outcnt() == 0) 330 continue; // Safe case - no loops 331 if (phi->outcnt() == 1) { 332 Node* u = phi->raw_out(0); 333 // Skip if only one use is an other Phi or Call or Uncommon trap. 334 // It is safe to consider this case as fallthrough. 335 if (u != NULL && (u->is_Phi() || u->is_CFG())) 336 continue; 337 } 338 // Check when phi references itself directly or through an other node. 339 if (phi->as_Phi()->simple_data_loop_check(phi->in(1)) >= PhiNode::Unsafe) 340 break; // Found possible unsafe data loop. 341 } 342 } 343 if (i >= max) 344 return false; // An unsafe case was NOT found - don't need graph walk. 345 346 // Unsafe case - check if the Region node is reachable from root. 347 ResourceMark rm; 348 349 Arena *a = Thread::current()->resource_area(); 350 Node_List nstack(a); 351 VectorSet visited(a); 352 353 // Mark all control nodes reachable from root outputs 354 Node *n = (Node*)phase->C->root(); 355 nstack.push(n); 356 visited.set(n->_idx); 357 while (nstack.size() != 0) { 358 n = nstack.pop(); 359 uint max = n->outcnt(); 360 for (uint i = 0; i < max; i++) { 361 Node* m = n->raw_out(i); 362 if (m != NULL && m->is_CFG()) { 363 if (phase->eqv(m, this)) { 364 return false; // We reached the Region node - it is not dead. 365 } 366 if (!visited.test_set(m->_idx)) 367 nstack.push(m); 368 } 369 } 370 } 371 372 return true; // The Region node is unreachable - it is dead. 373 } 374 375 bool RegionNode::try_clean_mem_phi(PhaseGVN *phase) { 376 // Incremental inlining + PhaseStringOpts sometimes produce: 377 // 378 // cmpP with 1 top input 379 // | 380 // If 381 // / \ 382 // IfFalse IfTrue /- Some Node 383 // \ / / / 384 // Region / /-MergeMem 385 // \---Phi 386 // 387 // 388 // It's expected by PhaseStringOpts that the Region goes away and is 389 // replaced by If's control input but because there's still a Phi, 390 // the Region stays in the graph. The top input from the cmpP is 391 // propagated forward and a subgraph that is useful goes away. The 392 // code below replaces the Phi with the MergeMem so that the Region 393 // is simplified. 394 395 PhiNode* phi = has_unique_phi(); 396 if (phi && phi->type() == Type::MEMORY && req() == 3 && phi->is_diamond_phi(true)) { 397 MergeMemNode* m = NULL; 398 assert(phi->req() == 3, "same as region"); 399 for (uint i = 1; i < 3; ++i) { 400 Node *mem = phi->in(i); 401 if (mem && mem->is_MergeMem() && in(i)->outcnt() == 1) { 402 // Nothing is control-dependent on path #i except the region itself. 403 m = mem->as_MergeMem(); 404 uint j = 3 - i; 405 Node* other = phi->in(j); 406 if (other && other == m->base_memory()) { 407 // m is a successor memory to other, and is not pinned inside the diamond, so push it out. 408 // This will allow the diamond to collapse completely. 409 phase->is_IterGVN()->replace_node(phi, m); 410 return true; 411 } 412 } 413 } 414 } 415 return false; 416 } 417 418 //------------------------------Ideal------------------------------------------ 419 // Return a node which is more "ideal" than the current node. Must preserve 420 // the CFG, but we can still strip out dead paths. 421 Node *RegionNode::Ideal(PhaseGVN *phase, bool can_reshape) { 422 if( !can_reshape && !in(0) ) return NULL; // Already degraded to a Copy 423 assert(!in(0) || !in(0)->is_Root(), "not a specially hidden merge"); 424 425 // Check for RegionNode with no Phi users and both inputs come from either 426 // arm of the same IF. If found, then the control-flow split is useless. 427 bool has_phis = false; 428 if (can_reshape) { // Need DU info to check for Phi users 429 has_phis = (has_phi() != NULL); // Cache result 430 if (has_phis && try_clean_mem_phi(phase)) { 431 has_phis = false; 432 } 433 434 if (!has_phis) { // No Phi users? Nothing merging? 435 for (uint i = 1; i < req()-1; i++) { 436 Node *if1 = in(i); 437 if( !if1 ) continue; 438 Node *iff = if1->in(0); 439 if( !iff || !iff->is_If() ) continue; 440 for( uint j=i+1; j<req(); j++ ) { 441 if( in(j) && in(j)->in(0) == iff && 442 if1->Opcode() != in(j)->Opcode() ) { 443 // Add the IF Projections to the worklist. They (and the IF itself) 444 // will be eliminated if dead. 445 phase->is_IterGVN()->add_users_to_worklist(iff); 446 set_req(i, iff->in(0));// Skip around the useless IF diamond 447 set_req(j, NULL); 448 return this; // Record progress 449 } 450 } 451 } 452 } 453 } 454 455 // Remove TOP or NULL input paths. If only 1 input path remains, this Region 456 // degrades to a copy. 457 bool add_to_worklist = false; 458 bool modified = false; 459 int cnt = 0; // Count of values merging 460 DEBUG_ONLY( int cnt_orig = req(); ) // Save original inputs count 461 int del_it = 0; // The last input path we delete 462 // For all inputs... 463 for( uint i=1; i<req(); ++i ){// For all paths in 464 Node *n = in(i); // Get the input 465 if( n != NULL ) { 466 // Remove useless control copy inputs 467 if( n->is_Region() && n->as_Region()->is_copy() ) { 468 set_req(i, n->nonnull_req()); 469 modified = true; 470 i--; 471 continue; 472 } 473 if( n->is_Proj() ) { // Remove useless rethrows 474 Node *call = n->in(0); 475 if (call->is_Call() && call->as_Call()->entry_point() == OptoRuntime::rethrow_stub()) { 476 set_req(i, call->in(0)); 477 modified = true; 478 i--; 479 continue; 480 } 481 } 482 if( phase->type(n) == Type::TOP ) { 483 set_req(i, NULL); // Ignore TOP inputs 484 modified = true; 485 i--; 486 continue; 487 } 488 cnt++; // One more value merging 489 490 } else if (can_reshape) { // Else found dead path with DU info 491 PhaseIterGVN *igvn = phase->is_IterGVN(); 492 del_req(i); // Yank path from self 493 del_it = i; 494 uint max = outcnt(); 495 DUIterator j; 496 bool progress = true; 497 while(progress) { // Need to establish property over all users 498 progress = false; 499 for (j = outs(); has_out(j); j++) { 500 Node *n = out(j); 501 if( n->req() != req() && n->is_Phi() ) { 502 assert( n->in(0) == this, "" ); 503 igvn->hash_delete(n); // Yank from hash before hacking edges 504 n->set_req_X(i,NULL,igvn);// Correct DU info 505 n->del_req(i); // Yank path from Phis 506 if( max != outcnt() ) { 507 progress = true; 508 j = refresh_out_pos(j); 509 max = outcnt(); 510 } 511 } 512 } 513 } 514 add_to_worklist = true; 515 i--; 516 } 517 } 518 519 if (can_reshape && cnt == 1) { 520 // Is it dead loop? 521 // If it is LoopNopde it had 2 (+1 itself) inputs and 522 // one of them was cut. The loop is dead if it was EntryContol. 523 // Loop node may have only one input because entry path 524 // is removed in PhaseIdealLoop::Dominators(). 525 assert(!this->is_Loop() || cnt_orig <= 3, "Loop node should have 3 or less inputs"); 526 if ((this->is_Loop() && (del_it == LoopNode::EntryControl || 527 (del_it == 0 && is_unreachable_region(phase)))) || 528 (!this->is_Loop() && has_phis && is_unreachable_region(phase))) { 529 // Yes, the region will be removed during the next step below. 530 // Cut the backedge input and remove phis since no data paths left. 531 // We don't cut outputs to other nodes here since we need to put them 532 // on the worklist. 533 PhaseIterGVN *igvn = phase->is_IterGVN(); 534 if (in(1)->outcnt() == 1) { 535 igvn->_worklist.push(in(1)); 536 } 537 del_req(1); 538 cnt = 0; 539 assert( req() == 1, "no more inputs expected" ); 540 uint max = outcnt(); 541 bool progress = true; 542 Node *top = phase->C->top(); 543 DUIterator j; 544 while(progress) { 545 progress = false; 546 for (j = outs(); has_out(j); j++) { 547 Node *n = out(j); 548 if( n->is_Phi() ) { 549 assert( igvn->eqv(n->in(0), this), "" ); 550 assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" ); 551 // Break dead loop data path. 552 // Eagerly replace phis with top to avoid phis copies generation. 553 igvn->replace_node(n, top); 554 if( max != outcnt() ) { 555 progress = true; 556 j = refresh_out_pos(j); 557 max = outcnt(); 558 } 559 } 560 } 561 } 562 add_to_worklist = true; 563 } 564 } 565 if (add_to_worklist) { 566 phase->is_IterGVN()->add_users_to_worklist(this); // Revisit collapsed Phis 567 } 568 569 if( cnt <= 1 ) { // Only 1 path in? 570 set_req(0, NULL); // Null control input for region copy 571 if( cnt == 0 && !can_reshape) { // Parse phase - leave the node as it is. 572 // No inputs or all inputs are NULL. 573 return NULL; 574 } else if (can_reshape) { // Optimization phase - remove the node 575 PhaseIterGVN *igvn = phase->is_IterGVN(); 576 // Strip mined (inner) loop is going away, remove outer loop. 577 if (is_CountedLoop() && 578 as_Loop()->is_strip_mined()) { 579 Node* outer_sfpt = as_CountedLoop()->outer_safepoint(); 580 Node* outer_out = as_CountedLoop()->outer_loop_exit(); 581 if (outer_sfpt != NULL && outer_out != NULL) { 582 Node* in = outer_sfpt->in(0); 583 igvn->replace_node(outer_out, in); 584 LoopNode* outer = as_CountedLoop()->outer_loop(); 585 igvn->replace_input_of(outer, LoopNode::LoopBackControl, igvn->C->top()); 586 } 587 } 588 Node *parent_ctrl; 589 if( cnt == 0 ) { 590 assert( req() == 1, "no inputs expected" ); 591 // During IGVN phase such region will be subsumed by TOP node 592 // so region's phis will have TOP as control node. 593 // Kill phis here to avoid it. PhiNode::is_copy() will be always false. 594 // Also set other user's input to top. 595 parent_ctrl = phase->C->top(); 596 } else { 597 // The fallthrough case since we already checked dead loops above. 598 parent_ctrl = in(1); 599 assert(parent_ctrl != NULL, "Region is a copy of some non-null control"); 600 assert(!igvn->eqv(parent_ctrl, this), "Close dead loop"); 601 } 602 if (!add_to_worklist) 603 igvn->add_users_to_worklist(this); // Check for further allowed opts 604 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) { 605 Node* n = last_out(i); 606 igvn->hash_delete(n); // Remove from worklist before modifying edges 607 if( n->is_Phi() ) { // Collapse all Phis 608 // Eagerly replace phis to avoid copies generation. 609 Node* in; 610 if( cnt == 0 ) { 611 assert( n->req() == 1, "No data inputs expected" ); 612 in = parent_ctrl; // replaced by top 613 } else { 614 assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" ); 615 in = n->in(1); // replaced by unique input 616 if( n->as_Phi()->is_unsafe_data_reference(in) ) 617 in = phase->C->top(); // replaced by top 618 } 619 igvn->replace_node(n, in); 620 } 621 else if( n->is_Region() ) { // Update all incoming edges 622 assert( !igvn->eqv(n, this), "Must be removed from DefUse edges"); 623 uint uses_found = 0; 624 for( uint k=1; k < n->req(); k++ ) { 625 if( n->in(k) == this ) { 626 n->set_req(k, parent_ctrl); 627 uses_found++; 628 } 629 } 630 if( uses_found > 1 ) { // (--i) done at the end of the loop. 631 i -= (uses_found - 1); 632 } 633 } 634 else { 635 assert( igvn->eqv(n->in(0), this), "Expect RegionNode to be control parent"); 636 n->set_req(0, parent_ctrl); 637 } 638 #ifdef ASSERT 639 for( uint k=0; k < n->req(); k++ ) { 640 assert( !igvn->eqv(n->in(k), this), "All uses of RegionNode should be gone"); 641 } 642 #endif 643 } 644 // Remove the RegionNode itself from DefUse info 645 igvn->remove_dead_node(this); 646 return NULL; 647 } 648 return this; // Record progress 649 } 650 651 652 // If a Region flows into a Region, merge into one big happy merge. 653 if (can_reshape) { 654 Node *m = merge_region(this, phase); 655 if (m != NULL) return m; 656 } 657 658 // Check if this region is the root of a clipping idiom on floats 659 if( ConvertFloat2IntClipping && can_reshape && req() == 4 ) { 660 // Check that only one use is a Phi and that it simplifies to two constants + 661 PhiNode* phi = has_unique_phi(); 662 if (phi != NULL) { // One Phi user 663 // Check inputs to the Phi 664 ConNode *min; 665 ConNode *max; 666 Node *val; 667 uint min_idx; 668 uint max_idx; 669 uint val_idx; 670 if( check_phi_clipping( phi, min, min_idx, max, max_idx, val, val_idx ) ) { 671 IfNode *top_if; 672 IfNode *bot_if; 673 if( check_if_clipping( this, bot_if, top_if ) ) { 674 // Control pattern checks, now verify compares 675 Node *top_in = NULL; // value being compared against 676 Node *bot_in = NULL; 677 if( check_compare_clipping( true, bot_if, min, bot_in ) && 678 check_compare_clipping( false, top_if, max, top_in ) ) { 679 if( bot_in == top_in ) { 680 PhaseIterGVN *gvn = phase->is_IterGVN(); 681 assert( gvn != NULL, "Only had DefUse info in IterGVN"); 682 // Only remaining check is that bot_in == top_in == (Phi's val + mods) 683 684 // Check for the ConvF2INode 685 ConvF2INode *convf2i; 686 if( check_convf2i_clipping( phi, val_idx, convf2i, min, max ) && 687 convf2i->in(1) == bot_in ) { 688 // Matched pattern, including LShiftI; RShiftI, replace with integer compares 689 // max test 690 Node *cmp = gvn->register_new_node_with_optimizer(new CmpINode( convf2i, min )); 691 Node *boo = gvn->register_new_node_with_optimizer(new BoolNode( cmp, BoolTest::lt )); 692 IfNode *iff = (IfNode*)gvn->register_new_node_with_optimizer(new IfNode( top_if->in(0), boo, PROB_UNLIKELY_MAG(5), top_if->_fcnt )); 693 Node *if_min= gvn->register_new_node_with_optimizer(new IfTrueNode (iff)); 694 Node *ifF = gvn->register_new_node_with_optimizer(new IfFalseNode(iff)); 695 // min test 696 cmp = gvn->register_new_node_with_optimizer(new CmpINode( convf2i, max )); 697 boo = gvn->register_new_node_with_optimizer(new BoolNode( cmp, BoolTest::gt )); 698 iff = (IfNode*)gvn->register_new_node_with_optimizer(new IfNode( ifF, boo, PROB_UNLIKELY_MAG(5), bot_if->_fcnt )); 699 Node *if_max= gvn->register_new_node_with_optimizer(new IfTrueNode (iff)); 700 ifF = gvn->register_new_node_with_optimizer(new IfFalseNode(iff)); 701 // update input edges to region node 702 set_req_X( min_idx, if_min, gvn ); 703 set_req_X( max_idx, if_max, gvn ); 704 set_req_X( val_idx, ifF, gvn ); 705 // remove unnecessary 'LShiftI; RShiftI' idiom 706 gvn->hash_delete(phi); 707 phi->set_req_X( val_idx, convf2i, gvn ); 708 gvn->hash_find_insert(phi); 709 // Return transformed region node 710 return this; 711 } 712 } 713 } 714 } 715 } 716 } 717 } 718 719 if (can_reshape) { 720 modified |= optimize_trichotomy(phase->is_IterGVN()); 721 } 722 723 return modified ? this : NULL; 724 } 725 726 //------------------------------optimize_trichotomy-------------------------- 727 // Optimize nested comparisons of the following kind: 728 // 729 // int compare(int a, int b) { 730 // return (a < b) ? -1 : (a == b) ? 0 : 1; 731 // } 732 // 733 // Shape 1: 734 // if (compare(a, b) == 1) { ... } -> if (a > b) { ... } 735 // 736 // Shape 2: 737 // if (compare(a, b) == 0) { ... } -> if (a == b) { ... } 738 // 739 // Above code leads to the following IR shapes where both Ifs compare the 740 // same value and two out of three region inputs idx1 and idx2 map to 741 // the same value and control flow. 742 // 743 // (1) If (2) If 744 // / \ / \ 745 // Proj Proj Proj Proj 746 // | \ | \ 747 // | If | If If 748 // | / \ | / \ / \ 749 // | Proj Proj | Proj Proj ==> Proj Proj 750 // | / / \ | / | / 751 // Region / \ | / | / 752 // \ / \ | / | / 753 // Region Region Region 754 // 755 // The method returns true if 'this' is modified and false otherwise. 756 bool RegionNode::optimize_trichotomy(PhaseIterGVN* igvn) { 757 int idx1 = 1, idx2 = 2; 758 Node* region = NULL; 759 if (req() == 3 && in(1) != NULL && in(2) != NULL) { 760 // Shape 1: Check if one of the inputs is a region that merges two control 761 // inputs and has no other users (especially no Phi users). 762 region = in(1)->isa_Region() ? in(1) : in(2)->isa_Region(); 763 if (region == NULL || region->outcnt() != 2 || region->req() != 3) { 764 return false; // No suitable region input found 765 } 766 } else if (req() == 4) { 767 // Shape 2: Check if two control inputs map to the same value of the unique phi 768 // user and treat these as if they would come from another region (shape (1)). 769 PhiNode* phi = has_unique_phi(); 770 if (phi == NULL) { 771 return false; // No unique phi user 772 } 773 if (phi->in(idx1) != phi->in(idx2)) { 774 idx2 = 3; 775 if (phi->in(idx1) != phi->in(idx2)) { 776 idx1 = 2; 777 if (phi->in(idx1) != phi->in(idx2)) { 778 return false; // No equal phi inputs found 779 } 780 } 781 } 782 assert(phi->in(idx1) == phi->in(idx2), "must be"); // Region is merging same value 783 region = this; 784 } 785 if (region == NULL || region->in(idx1) == NULL || region->in(idx2) == NULL) { 786 return false; // Region does not merge two control inputs 787 } 788 // At this point we know that region->in(idx1) and region->(idx2) map to the same 789 // value and control flow. Now search for ifs that feed into these region inputs. 790 ProjNode* proj1 = region->in(idx1)->isa_Proj(); 791 ProjNode* proj2 = region->in(idx2)->isa_Proj(); 792 if (proj1 == NULL || proj1->outcnt() != 1 || 793 proj2 == NULL || proj2->outcnt() != 1) { 794 return false; // No projection inputs with region as unique user found 795 } 796 assert(proj1 != proj2, "should be different projections"); 797 IfNode* iff1 = proj1->in(0)->isa_If(); 798 IfNode* iff2 = proj2->in(0)->isa_If(); 799 if (iff1 == NULL || iff1->outcnt() != 2 || 800 iff2 == NULL || iff2->outcnt() != 2) { 801 return false; // No ifs found 802 } 803 if (iff1 == iff2) { 804 igvn->add_users_to_worklist(iff1); // Make sure dead if is eliminated 805 igvn->replace_input_of(region, idx1, iff1->in(0)); 806 igvn->replace_input_of(region, idx2, igvn->C->top()); 807 return (region == this); // Remove useless if (both projections map to the same control/value) 808 } 809 BoolNode* bol1 = iff1->in(1)->isa_Bool(); 810 BoolNode* bol2 = iff2->in(1)->isa_Bool(); 811 if (bol1 == NULL || bol2 == NULL) { 812 return false; // No bool inputs found 813 } 814 Node* cmp1 = bol1->in(1); 815 Node* cmp2 = bol2->in(1); 816 bool commute = false; 817 if (!cmp1->is_Cmp() || !cmp2->is_Cmp()) { 818 return false; // No comparison 819 } else if (cmp1->Opcode() == Op_CmpF || cmp1->Opcode() == Op_CmpD || 820 cmp2->Opcode() == Op_CmpF || cmp2->Opcode() == Op_CmpD || 821 cmp1->Opcode() == Op_CmpP || cmp1->Opcode() == Op_CmpN || 822 cmp2->Opcode() == Op_CmpP || cmp2->Opcode() == Op_CmpN) { 823 // Floats and pointers don't exactly obey trichotomy. To be on the safe side, don't transform their tests. 824 return false; 825 } else if (cmp1 != cmp2) { 826 if (cmp1->in(1) == cmp2->in(2) && 827 cmp1->in(2) == cmp2->in(1)) { 828 commute = true; // Same but swapped inputs, commute the test 829 } else { 830 return false; // Ifs are not comparing the same values 831 } 832 } 833 proj1 = proj1->other_if_proj(); 834 proj2 = proj2->other_if_proj(); 835 if (!((proj1->unique_ctrl_out() == iff2 && 836 proj2->unique_ctrl_out() == this) || 837 (proj2->unique_ctrl_out() == iff1 && 838 proj1->unique_ctrl_out() == this))) { 839 return false; // Ifs are not connected through other projs 840 } 841 // Found 'iff -> proj -> iff -> proj -> this' shape where all other projs are merged 842 // through 'region' and map to the same value. Merge the boolean tests and replace 843 // the ifs by a single comparison. 844 BoolTest test1 = (proj1->_con == 1) ? bol1->_test : bol1->_test.negate(); 845 BoolTest test2 = (proj2->_con == 1) ? bol2->_test : bol2->_test.negate(); 846 test1 = commute ? test1.commute() : test1; 847 // After possibly commuting test1, if we can merge test1 & test2, then proj2/iff2/bol2 are the nodes to refine. 848 BoolTest::mask res = test1.merge(test2); 849 if (res == BoolTest::illegal) { 850 return false; // Unable to merge tests 851 } 852 // Adjust iff1 to always pass (only iff2 will remain) 853 igvn->replace_input_of(iff1, 1, igvn->intcon(proj1->_con)); 854 if (res == BoolTest::never) { 855 // Merged test is always false, adjust iff2 to always fail 856 igvn->replace_input_of(iff2, 1, igvn->intcon(1 - proj2->_con)); 857 } else { 858 // Replace bool input of iff2 with merged test 859 BoolNode* new_bol = new BoolNode(bol2->in(1), res); 860 igvn->replace_input_of(iff2, 1, igvn->transform((proj2->_con == 1) ? new_bol : new_bol->negate(igvn))); 861 } 862 return false; 863 } 864 865 const RegMask &RegionNode::out_RegMask() const { 866 return RegMask::Empty; 867 } 868 869 // Find the one non-null required input. RegionNode only 870 Node *Node::nonnull_req() const { 871 assert( is_Region(), "" ); 872 for( uint i = 1; i < _cnt; i++ ) 873 if( in(i) ) 874 return in(i); 875 ShouldNotReachHere(); 876 return NULL; 877 } 878 879 880 //============================================================================= 881 // note that these functions assume that the _adr_type field is flattened 882 uint PhiNode::hash() const { 883 const Type* at = _adr_type; 884 return TypeNode::hash() + (at ? at->hash() : 0); 885 } 886 uint PhiNode::cmp( const Node &n ) const { 887 return TypeNode::cmp(n) && _adr_type == ((PhiNode&)n)._adr_type; 888 } 889 static inline 890 const TypePtr* flatten_phi_adr_type(const TypePtr* at) { 891 if (at == NULL || at == TypePtr::BOTTOM) return at; 892 return Compile::current()->alias_type(at)->adr_type(); 893 } 894 895 //----------------------------make--------------------------------------------- 896 // create a new phi with edges matching r and set (initially) to x 897 PhiNode* PhiNode::make(Node* r, Node* x, const Type *t, const TypePtr* at) { 898 uint preds = r->req(); // Number of predecessor paths 899 assert(t != Type::MEMORY || at == flatten_phi_adr_type(at), "flatten at"); 900 PhiNode* p = new PhiNode(r, t, at); 901 for (uint j = 1; j < preds; j++) { 902 // Fill in all inputs, except those which the region does not yet have 903 if (r->in(j) != NULL) 904 p->init_req(j, x); 905 } 906 return p; 907 } 908 PhiNode* PhiNode::make(Node* r, Node* x) { 909 const Type* t = x->bottom_type(); 910 const TypePtr* at = NULL; 911 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); 912 return make(r, x, t, at); 913 } 914 PhiNode* PhiNode::make_blank(Node* r, Node* x) { 915 const Type* t = x->bottom_type(); 916 const TypePtr* at = NULL; 917 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); 918 return new PhiNode(r, t, at); 919 } 920 921 922 //------------------------slice_memory----------------------------------------- 923 // create a new phi with narrowed memory type 924 PhiNode* PhiNode::slice_memory(const TypePtr* adr_type) const { 925 PhiNode* mem = (PhiNode*) clone(); 926 *(const TypePtr**)&mem->_adr_type = adr_type; 927 // convert self-loops, or else we get a bad graph 928 for (uint i = 1; i < req(); i++) { 929 if ((const Node*)in(i) == this) mem->set_req(i, mem); 930 } 931 mem->verify_adr_type(); 932 return mem; 933 } 934 935 //------------------------split_out_instance----------------------------------- 936 // Split out an instance type from a bottom phi. 937 PhiNode* PhiNode::split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const { 938 const TypeOopPtr *t_oop = at->isa_oopptr(); 939 assert(t_oop != NULL && t_oop->is_known_instance(), "expecting instance oopptr"); 940 const TypePtr *t = adr_type(); 941 assert(type() == Type::MEMORY && 942 (t == TypePtr::BOTTOM || t == TypeRawPtr::BOTTOM || 943 t->isa_oopptr() && !t->is_oopptr()->is_known_instance() && 944 t->is_oopptr()->cast_to_exactness(true) 945 ->is_oopptr()->cast_to_ptr_type(t_oop->ptr()) 946 ->is_oopptr()->cast_to_instance_id(t_oop->instance_id()) == t_oop), 947 "bottom or raw memory required"); 948 949 // Check if an appropriate node already exists. 950 Node *region = in(0); 951 for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) { 952 Node* use = region->fast_out(k); 953 if( use->is_Phi()) { 954 PhiNode *phi2 = use->as_Phi(); 955 if (phi2->type() == Type::MEMORY && phi2->adr_type() == at) { 956 return phi2; 957 } 958 } 959 } 960 Compile *C = igvn->C; 961 Arena *a = Thread::current()->resource_area(); 962 Node_Array node_map = new Node_Array(a); 963 Node_Stack stack(a, C->live_nodes() >> 4); 964 PhiNode *nphi = slice_memory(at); 965 igvn->register_new_node_with_optimizer( nphi ); 966 node_map.map(_idx, nphi); 967 stack.push((Node *)this, 1); 968 while(!stack.is_empty()) { 969 PhiNode *ophi = stack.node()->as_Phi(); 970 uint i = stack.index(); 971 assert(i >= 1, "not control edge"); 972 stack.pop(); 973 nphi = node_map[ophi->_idx]->as_Phi(); 974 for (; i < ophi->req(); i++) { 975 Node *in = ophi->in(i); 976 if (in == NULL || igvn->type(in) == Type::TOP) 977 continue; 978 Node *opt = MemNode::optimize_simple_memory_chain(in, t_oop, NULL, igvn); 979 PhiNode *optphi = opt->is_Phi() ? opt->as_Phi() : NULL; 980 if (optphi != NULL && optphi->adr_type() == TypePtr::BOTTOM) { 981 opt = node_map[optphi->_idx]; 982 if (opt == NULL) { 983 stack.push(ophi, i); 984 nphi = optphi->slice_memory(at); 985 igvn->register_new_node_with_optimizer( nphi ); 986 node_map.map(optphi->_idx, nphi); 987 ophi = optphi; 988 i = 0; // will get incremented at top of loop 989 continue; 990 } 991 } 992 nphi->set_req(i, opt); 993 } 994 } 995 return nphi; 996 } 997 998 //------------------------verify_adr_type-------------------------------------- 999 #ifdef ASSERT 1000 void PhiNode::verify_adr_type(VectorSet& visited, const TypePtr* at) const { 1001 if (visited.test_set(_idx)) return; //already visited 1002 1003 // recheck constructor invariants: 1004 verify_adr_type(false); 1005 1006 // recheck local phi/phi consistency: 1007 assert(_adr_type == at || _adr_type == TypePtr::BOTTOM, 1008 "adr_type must be consistent across phi nest"); 1009 1010 // walk around 1011 for (uint i = 1; i < req(); i++) { 1012 Node* n = in(i); 1013 if (n == NULL) continue; 1014 const Node* np = in(i); 1015 if (np->is_Phi()) { 1016 np->as_Phi()->verify_adr_type(visited, at); 1017 } else if (n->bottom_type() == Type::TOP 1018 || (n->is_Mem() && n->in(MemNode::Address)->bottom_type() == Type::TOP)) { 1019 // ignore top inputs 1020 } else { 1021 const TypePtr* nat = flatten_phi_adr_type(n->adr_type()); 1022 // recheck phi/non-phi consistency at leaves: 1023 assert((nat != NULL) == (at != NULL), ""); 1024 assert(nat == at || nat == TypePtr::BOTTOM, 1025 "adr_type must be consistent at leaves of phi nest"); 1026 } 1027 } 1028 } 1029 1030 // Verify a whole nest of phis rooted at this one. 1031 void PhiNode::verify_adr_type(bool recursive) const { 1032 if (VMError::is_error_reported()) return; // muzzle asserts when debugging an error 1033 if (Node::in_dump()) return; // muzzle asserts when printing 1034 1035 assert((_type == Type::MEMORY) == (_adr_type != NULL), "adr_type for memory phis only"); 1036 1037 if (!VerifyAliases) return; // verify thoroughly only if requested 1038 1039 assert(_adr_type == flatten_phi_adr_type(_adr_type), 1040 "Phi::adr_type must be pre-normalized"); 1041 1042 if (recursive) { 1043 VectorSet visited(Thread::current()->resource_area()); 1044 verify_adr_type(visited, _adr_type); 1045 } 1046 } 1047 #endif 1048 1049 1050 //------------------------------Value------------------------------------------ 1051 // Compute the type of the PhiNode 1052 const Type* PhiNode::Value(PhaseGVN* phase) const { 1053 Node *r = in(0); // RegionNode 1054 if( !r ) // Copy or dead 1055 return in(1) ? phase->type(in(1)) : Type::TOP; 1056 1057 // Note: During parsing, phis are often transformed before their regions. 1058 // This means we have to use type_or_null to defend against untyped regions. 1059 if( phase->type_or_null(r) == Type::TOP ) // Dead code? 1060 return Type::TOP; 1061 1062 // Check for trip-counted loop. If so, be smarter. 1063 CountedLoopNode* l = r->is_CountedLoop() ? r->as_CountedLoop() : NULL; 1064 if (l && ((const Node*)l->phi() == this)) { // Trip counted loop! 1065 // protect against init_trip() or limit() returning NULL 1066 if (l->can_be_counted_loop(phase)) { 1067 const Node *init = l->init_trip(); 1068 const Node *limit = l->limit(); 1069 const Node* stride = l->stride(); 1070 if (init != NULL && limit != NULL && stride != NULL) { 1071 const TypeInt* lo = phase->type(init)->isa_int(); 1072 const TypeInt* hi = phase->type(limit)->isa_int(); 1073 const TypeInt* stride_t = phase->type(stride)->isa_int(); 1074 if (lo != NULL && hi != NULL && stride_t != NULL) { // Dying loops might have TOP here 1075 assert(stride_t->_hi >= stride_t->_lo, "bad stride type"); 1076 BoolTest::mask bt = l->loopexit()->test_trip(); 1077 // If the loop exit condition is "not equal", the condition 1078 // would not trigger if init > limit (if stride > 0) or if 1079 // init < limit if (stride > 0) so we can't deduce bounds 1080 // for the iv from the exit condition. 1081 if (bt != BoolTest::ne) { 1082 if (stride_t->_hi < 0) { // Down-counter loop 1083 swap(lo, hi); 1084 return TypeInt::make(MIN2(lo->_lo, hi->_lo) , hi->_hi, 3); 1085 } else if (stride_t->_lo >= 0) { 1086 return TypeInt::make(lo->_lo, MAX2(lo->_hi, hi->_hi), 3); 1087 } 1088 } 1089 } 1090 } 1091 } else if (l->in(LoopNode::LoopBackControl) != NULL && 1092 in(LoopNode::EntryControl) != NULL && 1093 phase->type(l->in(LoopNode::LoopBackControl)) == Type::TOP) { 1094 // During CCP, if we saturate the type of a counted loop's Phi 1095 // before the special code for counted loop above has a chance 1096 // to run (that is as long as the type of the backedge's control 1097 // is top), we might end up with non monotonic types 1098 return phase->type(in(LoopNode::EntryControl))->filter_speculative(_type); 1099 } 1100 } 1101 1102 // Until we have harmony between classes and interfaces in the type 1103 // lattice, we must tread carefully around phis which implicitly 1104 // convert the one to the other. 1105 const TypePtr* ttp = _type->make_ptr(); 1106 const TypeInstPtr* ttip = (ttp != NULL) ? ttp->isa_instptr() : NULL; 1107 const TypeKlassPtr* ttkp = (ttp != NULL) ? ttp->isa_klassptr() : NULL; 1108 bool is_intf = false; 1109 if (ttip != NULL) { 1110 ciKlass* k = ttip->klass(); 1111 if (k->is_loaded() && k->is_interface()) 1112 is_intf = true; 1113 } 1114 if (ttkp != NULL) { 1115 ciKlass* k = ttkp->klass(); 1116 if (k->is_loaded() && k->is_interface()) 1117 is_intf = true; 1118 } 1119 1120 // Default case: merge all inputs 1121 const Type *t = Type::TOP; // Merged type starting value 1122 for (uint i = 1; i < req(); ++i) {// For all paths in 1123 // Reachable control path? 1124 if (r->in(i) && phase->type(r->in(i)) == Type::CONTROL) { 1125 const Type* ti = phase->type(in(i)); 1126 // We assume that each input of an interface-valued Phi is a true 1127 // subtype of that interface. This might not be true of the meet 1128 // of all the input types. The lattice is not distributive in 1129 // such cases. Ward off asserts in type.cpp by refusing to do 1130 // meets between interfaces and proper classes. 1131 const TypePtr* tip = ti->make_ptr(); 1132 const TypeInstPtr* tiip = (tip != NULL) ? tip->isa_instptr() : NULL; 1133 if (tiip) { 1134 bool ti_is_intf = false; 1135 ciKlass* k = tiip->klass(); 1136 if (k->is_loaded() && k->is_interface()) 1137 ti_is_intf = true; 1138 if (is_intf != ti_is_intf) 1139 { t = _type; break; } 1140 } 1141 t = t->meet_speculative(ti); 1142 } 1143 } 1144 1145 // The worst-case type (from ciTypeFlow) should be consistent with "t". 1146 // That is, we expect that "t->higher_equal(_type)" holds true. 1147 // There are various exceptions: 1148 // - Inputs which are phis might in fact be widened unnecessarily. 1149 // For example, an input might be a widened int while the phi is a short. 1150 // - Inputs might be BotPtrs but this phi is dependent on a null check, 1151 // and postCCP has removed the cast which encodes the result of the check. 1152 // - The type of this phi is an interface, and the inputs are classes. 1153 // - Value calls on inputs might produce fuzzy results. 1154 // (Occurrences of this case suggest improvements to Value methods.) 1155 // 1156 // It is not possible to see Type::BOTTOM values as phi inputs, 1157 // because the ciTypeFlow pre-pass produces verifier-quality types. 1158 const Type* ft = t->filter_speculative(_type); // Worst case type 1159 1160 #ifdef ASSERT 1161 // The following logic has been moved into TypeOopPtr::filter. 1162 const Type* jt = t->join_speculative(_type); 1163 if (jt->empty()) { // Emptied out??? 1164 1165 // Check for evil case of 't' being a class and '_type' expecting an 1166 // interface. This can happen because the bytecodes do not contain 1167 // enough type info to distinguish a Java-level interface variable 1168 // from a Java-level object variable. If we meet 2 classes which 1169 // both implement interface I, but their meet is at 'j/l/O' which 1170 // doesn't implement I, we have no way to tell if the result should 1171 // be 'I' or 'j/l/O'. Thus we'll pick 'j/l/O'. If this then flows 1172 // into a Phi which "knows" it's an Interface type we'll have to 1173 // uplift the type. 1174 if (!t->empty() && ttip && ttip->is_loaded() && ttip->klass()->is_interface()) { 1175 assert(ft == _type, ""); // Uplift to interface 1176 } else if (!t->empty() && ttkp && ttkp->is_loaded() && ttkp->klass()->is_interface()) { 1177 assert(ft == _type, ""); // Uplift to interface 1178 } else { 1179 // We also have to handle 'evil cases' of interface- vs. class-arrays 1180 Type::get_arrays_base_elements(jt, _type, NULL, &ttip); 1181 if (!t->empty() && ttip != NULL && ttip->is_loaded() && ttip->klass()->is_interface()) { 1182 assert(ft == _type, ""); // Uplift to array of interface 1183 } else { 1184 // Otherwise it's something stupid like non-overlapping int ranges 1185 // found on dying counted loops. 1186 assert(ft == Type::TOP, ""); // Canonical empty value 1187 } 1188 } 1189 } 1190 1191 else { 1192 1193 // If we have an interface-typed Phi and we narrow to a class type, the join 1194 // should report back the class. However, if we have a J/L/Object 1195 // class-typed Phi and an interface flows in, it's possible that the meet & 1196 // join report an interface back out. This isn't possible but happens 1197 // because the type system doesn't interact well with interfaces. 1198 const TypePtr *jtp = jt->make_ptr(); 1199 const TypeInstPtr *jtip = (jtp != NULL) ? jtp->isa_instptr() : NULL; 1200 const TypeKlassPtr *jtkp = (jtp != NULL) ? jtp->isa_klassptr() : NULL; 1201 if( jtip && ttip ) { 1202 if( jtip->is_loaded() && jtip->klass()->is_interface() && 1203 ttip->is_loaded() && !ttip->klass()->is_interface() ) { 1204 assert(ft == ttip->cast_to_ptr_type(jtip->ptr()) || 1205 ft->isa_narrowoop() && ft->make_ptr() == ttip->cast_to_ptr_type(jtip->ptr()), ""); 1206 jt = ft; 1207 } 1208 } 1209 if( jtkp && ttkp ) { 1210 if( jtkp->is_loaded() && jtkp->klass()->is_interface() && 1211 !jtkp->klass_is_exact() && // Keep exact interface klass (6894807) 1212 ttkp->is_loaded() && !ttkp->klass()->is_interface() ) { 1213 assert(ft == ttkp->cast_to_ptr_type(jtkp->ptr()) || 1214 ft->isa_narrowklass() && ft->make_ptr() == ttkp->cast_to_ptr_type(jtkp->ptr()), ""); 1215 jt = ft; 1216 } 1217 } 1218 if (jt != ft && jt->base() == ft->base()) { 1219 if (jt->isa_int() && 1220 jt->is_int()->_lo == ft->is_int()->_lo && 1221 jt->is_int()->_hi == ft->is_int()->_hi) 1222 jt = ft; 1223 if (jt->isa_long() && 1224 jt->is_long()->_lo == ft->is_long()->_lo && 1225 jt->is_long()->_hi == ft->is_long()->_hi) 1226 jt = ft; 1227 } 1228 if (jt != ft) { 1229 tty->print("merge type: "); t->dump(); tty->cr(); 1230 tty->print("kill type: "); _type->dump(); tty->cr(); 1231 tty->print("join type: "); jt->dump(); tty->cr(); 1232 tty->print("filter type: "); ft->dump(); tty->cr(); 1233 } 1234 assert(jt == ft, ""); 1235 } 1236 #endif //ASSERT 1237 1238 // Deal with conversion problems found in data loops. 1239 ft = phase->saturate(ft, phase->type_or_null(this), _type); 1240 1241 return ft; 1242 } 1243 1244 1245 //------------------------------is_diamond_phi--------------------------------- 1246 // Does this Phi represent a simple well-shaped diamond merge? Return the 1247 // index of the true path or 0 otherwise. 1248 // If check_control_only is true, do not inspect the If node at the 1249 // top, and return -1 (not an edge number) on success. 1250 int PhiNode::is_diamond_phi(bool check_control_only) const { 1251 // Check for a 2-path merge 1252 Node *region = in(0); 1253 if( !region ) return 0; 1254 if( region->req() != 3 ) return 0; 1255 if( req() != 3 ) return 0; 1256 // Check that both paths come from the same If 1257 Node *ifp1 = region->in(1); 1258 Node *ifp2 = region->in(2); 1259 if( !ifp1 || !ifp2 ) return 0; 1260 Node *iff = ifp1->in(0); 1261 if( !iff || !iff->is_If() ) return 0; 1262 if( iff != ifp2->in(0) ) return 0; 1263 if (check_control_only) return -1; 1264 // Check for a proper bool/cmp 1265 const Node *b = iff->in(1); 1266 if( !b->is_Bool() ) return 0; 1267 const Node *cmp = b->in(1); 1268 if( !cmp->is_Cmp() ) return 0; 1269 1270 // Check for branching opposite expected 1271 if( ifp2->Opcode() == Op_IfTrue ) { 1272 assert( ifp1->Opcode() == Op_IfFalse, "" ); 1273 return 2; 1274 } else { 1275 assert( ifp1->Opcode() == Op_IfTrue, "" ); 1276 return 1; 1277 } 1278 } 1279 1280 //----------------------------check_cmove_id----------------------------------- 1281 // Check for CMove'ing a constant after comparing against the constant. 1282 // Happens all the time now, since if we compare equality vs a constant in 1283 // the parser, we "know" the variable is constant on one path and we force 1284 // it. Thus code like "if( x==0 ) {/*EMPTY*/}" ends up inserting a 1285 // conditional move: "x = (x==0)?0:x;". Yucko. This fix is slightly more 1286 // general in that we don't need constants. Since CMove's are only inserted 1287 // in very special circumstances, we do it here on generic Phi's. 1288 Node* PhiNode::is_cmove_id(PhaseTransform* phase, int true_path) { 1289 assert(true_path !=0, "only diamond shape graph expected"); 1290 1291 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1292 // phi->region->if_proj->ifnode->bool->cmp 1293 Node* region = in(0); 1294 Node* iff = region->in(1)->in(0); 1295 BoolNode* b = iff->in(1)->as_Bool(); 1296 Node* cmp = b->in(1); 1297 Node* tval = in(true_path); 1298 Node* fval = in(3-true_path); 1299 Node* id = CMoveNode::is_cmove_id(phase, cmp, tval, fval, b); 1300 if (id == NULL) 1301 return NULL; 1302 1303 // Either value might be a cast that depends on a branch of 'iff'. 1304 // Since the 'id' value will float free of the diamond, either 1305 // decast or return failure. 1306 Node* ctl = id->in(0); 1307 if (ctl != NULL && ctl->in(0) == iff) { 1308 if (id->is_ConstraintCast()) { 1309 return id->in(1); 1310 } else { 1311 // Don't know how to disentangle this value. 1312 return NULL; 1313 } 1314 } 1315 1316 return id; 1317 } 1318 1319 //------------------------------Identity--------------------------------------- 1320 // Check for Region being Identity. 1321 Node* PhiNode::Identity(PhaseGVN* phase) { 1322 // Check for no merging going on 1323 // (There used to be special-case code here when this->region->is_Loop. 1324 // It would check for a tributary phi on the backedge that the main phi 1325 // trivially, perhaps with a single cast. The unique_input method 1326 // does all this and more, by reducing such tributaries to 'this'.) 1327 Node* uin = unique_input(phase, false); 1328 if (uin != NULL) { 1329 return uin; 1330 } 1331 1332 int true_path = is_diamond_phi(); 1333 if (true_path != 0) { 1334 Node* id = is_cmove_id(phase, true_path); 1335 if (id != NULL) return id; 1336 } 1337 1338 return this; // No identity 1339 } 1340 1341 //-----------------------------unique_input------------------------------------ 1342 // Find the unique value, discounting top, self-loops, and casts. 1343 // Return top if there are no inputs, and self if there are multiple. 1344 Node* PhiNode::unique_input(PhaseTransform* phase, bool uncast) { 1345 // 1) One unique direct input, 1346 // or if uncast is true: 1347 // 2) some of the inputs have an intervening ConstraintCast 1348 // 3) an input is a self loop 1349 // 1350 // 1) input or 2) input or 3) input __ 1351 // / \ / \ \ / \ 1352 // \ / | cast phi cast 1353 // phi \ / / \ / 1354 // phi / -- 1355 1356 Node* r = in(0); // RegionNode 1357 if (r == NULL) return in(1); // Already degraded to a Copy 1358 Node* input = NULL; // The unique direct input (maybe uncasted = ConstraintCasts removed) 1359 1360 for (uint i = 1, cnt = req(); i < cnt; ++i) { 1361 Node* rc = r->in(i); 1362 if (rc == NULL || phase->type(rc) == Type::TOP) 1363 continue; // ignore unreachable control path 1364 Node* n = in(i); 1365 if (n == NULL) 1366 continue; 1367 Node* un = n; 1368 if (uncast) { 1369 #ifdef ASSERT 1370 Node* m = un->uncast(); 1371 #endif 1372 while (un != NULL && un->req() == 2 && un->is_ConstraintCast()) { 1373 Node* next = un->in(1); 1374 if (phase->type(next)->isa_rawptr() && phase->type(un)->isa_oopptr()) { 1375 // risk exposing raw ptr at safepoint 1376 break; 1377 } 1378 un = next; 1379 } 1380 assert(m == un || un->in(1) == m, "Only expected at CheckCastPP from allocation"); 1381 } 1382 if (un == NULL || un == this || phase->type(un) == Type::TOP) { 1383 continue; // ignore if top, or in(i) and "this" are in a data cycle 1384 } 1385 // Check for a unique input (maybe uncasted) 1386 if (input == NULL) { 1387 input = un; 1388 } else if (input != un) { 1389 input = NodeSentinel; // no unique input 1390 } 1391 } 1392 if (input == NULL) { 1393 return phase->C->top(); // no inputs 1394 } 1395 1396 if (input != NodeSentinel) { 1397 return input; // one unique direct input 1398 } 1399 1400 // Nothing. 1401 return NULL; 1402 } 1403 1404 //------------------------------is_x2logic------------------------------------- 1405 // Check for simple convert-to-boolean pattern 1406 // If:(C Bool) Region:(IfF IfT) Phi:(Region 0 1) 1407 // Convert Phi to an ConvIB. 1408 static Node *is_x2logic( PhaseGVN *phase, PhiNode *phi, int true_path ) { 1409 assert(true_path !=0, "only diamond shape graph expected"); 1410 // Convert the true/false index into an expected 0/1 return. 1411 // Map 2->0 and 1->1. 1412 int flipped = 2-true_path; 1413 1414 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1415 // phi->region->if_proj->ifnode->bool->cmp 1416 Node *region = phi->in(0); 1417 Node *iff = region->in(1)->in(0); 1418 BoolNode *b = (BoolNode*)iff->in(1); 1419 const CmpNode *cmp = (CmpNode*)b->in(1); 1420 1421 Node *zero = phi->in(1); 1422 Node *one = phi->in(2); 1423 const Type *tzero = phase->type( zero ); 1424 const Type *tone = phase->type( one ); 1425 1426 // Check for compare vs 0 1427 const Type *tcmp = phase->type(cmp->in(2)); 1428 if( tcmp != TypeInt::ZERO && tcmp != TypePtr::NULL_PTR ) { 1429 // Allow cmp-vs-1 if the other input is bounded by 0-1 1430 if( !(tcmp == TypeInt::ONE && phase->type(cmp->in(1)) == TypeInt::BOOL) ) 1431 return NULL; 1432 flipped = 1-flipped; // Test is vs 1 instead of 0! 1433 } 1434 1435 // Check for setting zero/one opposite expected 1436 if( tzero == TypeInt::ZERO ) { 1437 if( tone == TypeInt::ONE ) { 1438 } else return NULL; 1439 } else if( tzero == TypeInt::ONE ) { 1440 if( tone == TypeInt::ZERO ) { 1441 flipped = 1-flipped; 1442 } else return NULL; 1443 } else return NULL; 1444 1445 // Check for boolean test backwards 1446 if( b->_test._test == BoolTest::ne ) { 1447 } else if( b->_test._test == BoolTest::eq ) { 1448 flipped = 1-flipped; 1449 } else return NULL; 1450 1451 // Build int->bool conversion 1452 Node *in1 = cmp->in(1); 1453 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2(); 1454 in1 = bs->step_over_gc_barrier(in1); 1455 Node *n = new Conv2BNode(in1); 1456 if( flipped ) 1457 n = new XorINode( phase->transform(n), phase->intcon(1) ); 1458 1459 return n; 1460 } 1461 1462 //------------------------------is_cond_add------------------------------------ 1463 // Check for simple conditional add pattern: "(P < Q) ? X+Y : X;" 1464 // To be profitable the control flow has to disappear; there can be no other 1465 // values merging here. We replace the test-and-branch with: 1466 // "(sgn(P-Q))&Y) + X". Basically, convert "(P < Q)" into 0 or -1 by 1467 // moving the carry bit from (P-Q) into a register with 'sbb EAX,EAX'. 1468 // Then convert Y to 0-or-Y and finally add. 1469 // This is a key transform for SpecJava _201_compress. 1470 static Node* is_cond_add(PhaseGVN *phase, PhiNode *phi, int true_path) { 1471 assert(true_path !=0, "only diamond shape graph expected"); 1472 1473 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1474 // phi->region->if_proj->ifnode->bool->cmp 1475 RegionNode *region = (RegionNode*)phi->in(0); 1476 Node *iff = region->in(1)->in(0); 1477 BoolNode* b = iff->in(1)->as_Bool(); 1478 const CmpNode *cmp = (CmpNode*)b->in(1); 1479 1480 // Make sure only merging this one phi here 1481 if (region->has_unique_phi() != phi) return NULL; 1482 1483 // Make sure each arm of the diamond has exactly one output, which we assume 1484 // is the region. Otherwise, the control flow won't disappear. 1485 if (region->in(1)->outcnt() != 1) return NULL; 1486 if (region->in(2)->outcnt() != 1) return NULL; 1487 1488 // Check for "(P < Q)" of type signed int 1489 if (b->_test._test != BoolTest::lt) return NULL; 1490 if (cmp->Opcode() != Op_CmpI) return NULL; 1491 1492 Node *p = cmp->in(1); 1493 Node *q = cmp->in(2); 1494 Node *n1 = phi->in( true_path); 1495 Node *n2 = phi->in(3-true_path); 1496 1497 int op = n1->Opcode(); 1498 if( op != Op_AddI // Need zero as additive identity 1499 /*&&op != Op_SubI && 1500 op != Op_AddP && 1501 op != Op_XorI && 1502 op != Op_OrI*/ ) 1503 return NULL; 1504 1505 Node *x = n2; 1506 Node *y = NULL; 1507 if( x == n1->in(1) ) { 1508 y = n1->in(2); 1509 } else if( x == n1->in(2) ) { 1510 y = n1->in(1); 1511 } else return NULL; 1512 1513 // Not so profitable if compare and add are constants 1514 if( q->is_Con() && phase->type(q) != TypeInt::ZERO && y->is_Con() ) 1515 return NULL; 1516 1517 Node *cmplt = phase->transform( new CmpLTMaskNode(p,q) ); 1518 Node *j_and = phase->transform( new AndINode(cmplt,y) ); 1519 return new AddINode(j_and,x); 1520 } 1521 1522 //------------------------------is_absolute------------------------------------ 1523 // Check for absolute value. 1524 static Node* is_absolute( PhaseGVN *phase, PhiNode *phi_root, int true_path) { 1525 assert(true_path !=0, "only diamond shape graph expected"); 1526 1527 int cmp_zero_idx = 0; // Index of compare input where to look for zero 1528 int phi_x_idx = 0; // Index of phi input where to find naked x 1529 1530 // ABS ends with the merge of 2 control flow paths. 1531 // Find the false path from the true path. With only 2 inputs, 3 - x works nicely. 1532 int false_path = 3 - true_path; 1533 1534 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1535 // phi->region->if_proj->ifnode->bool->cmp 1536 BoolNode *bol = phi_root->in(0)->in(1)->in(0)->in(1)->as_Bool(); 1537 1538 // Check bool sense 1539 switch( bol->_test._test ) { 1540 case BoolTest::lt: cmp_zero_idx = 1; phi_x_idx = true_path; break; 1541 case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break; 1542 case BoolTest::gt: cmp_zero_idx = 2; phi_x_idx = true_path; break; 1543 case BoolTest::ge: cmp_zero_idx = 1; phi_x_idx = false_path; break; 1544 default: return NULL; break; 1545 } 1546 1547 // Test is next 1548 Node *cmp = bol->in(1); 1549 const Type *tzero = NULL; 1550 switch( cmp->Opcode() ) { 1551 case Op_CmpF: tzero = TypeF::ZERO; break; // Float ABS 1552 case Op_CmpD: tzero = TypeD::ZERO; break; // Double ABS 1553 default: return NULL; 1554 } 1555 1556 // Find zero input of compare; the other input is being abs'd 1557 Node *x = NULL; 1558 bool flip = false; 1559 if( phase->type(cmp->in(cmp_zero_idx)) == tzero ) { 1560 x = cmp->in(3 - cmp_zero_idx); 1561 } else if( phase->type(cmp->in(3 - cmp_zero_idx)) == tzero ) { 1562 // The test is inverted, we should invert the result... 1563 x = cmp->in(cmp_zero_idx); 1564 flip = true; 1565 } else { 1566 return NULL; 1567 } 1568 1569 // Next get the 2 pieces being selected, one is the original value 1570 // and the other is the negated value. 1571 if( phi_root->in(phi_x_idx) != x ) return NULL; 1572 1573 // Check other phi input for subtract node 1574 Node *sub = phi_root->in(3 - phi_x_idx); 1575 1576 // Allow only Sub(0,X) and fail out for all others; Neg is not OK 1577 if( tzero == TypeF::ZERO ) { 1578 if( sub->Opcode() != Op_SubF || 1579 sub->in(2) != x || 1580 phase->type(sub->in(1)) != tzero ) return NULL; 1581 x = new AbsFNode(x); 1582 if (flip) { 1583 x = new SubFNode(sub->in(1), phase->transform(x)); 1584 } 1585 } else { 1586 if( sub->Opcode() != Op_SubD || 1587 sub->in(2) != x || 1588 phase->type(sub->in(1)) != tzero ) return NULL; 1589 x = new AbsDNode(x); 1590 if (flip) { 1591 x = new SubDNode(sub->in(1), phase->transform(x)); 1592 } 1593 } 1594 1595 return x; 1596 } 1597 1598 //------------------------------split_once------------------------------------- 1599 // Helper for split_flow_path 1600 static void split_once(PhaseIterGVN *igvn, Node *phi, Node *val, Node *n, Node *newn) { 1601 igvn->hash_delete(n); // Remove from hash before hacking edges 1602 1603 uint j = 1; 1604 for (uint i = phi->req()-1; i > 0; i--) { 1605 if (phi->in(i) == val) { // Found a path with val? 1606 // Add to NEW Region/Phi, no DU info 1607 newn->set_req( j++, n->in(i) ); 1608 // Remove from OLD Region/Phi 1609 n->del_req(i); 1610 } 1611 } 1612 1613 // Register the new node but do not transform it. Cannot transform until the 1614 // entire Region/Phi conglomerate has been hacked as a single huge transform. 1615 igvn->register_new_node_with_optimizer( newn ); 1616 1617 // Now I can point to the new node. 1618 n->add_req(newn); 1619 igvn->_worklist.push(n); 1620 } 1621 1622 //------------------------------split_flow_path-------------------------------- 1623 // Check for merging identical values and split flow paths 1624 static Node* split_flow_path(PhaseGVN *phase, PhiNode *phi) { 1625 BasicType bt = phi->type()->basic_type(); 1626 if( bt == T_ILLEGAL || type2size[bt] <= 0 ) 1627 return NULL; // Bail out on funny non-value stuff 1628 if( phi->req() <= 3 ) // Need at least 2 matched inputs and a 1629 return NULL; // third unequal input to be worth doing 1630 1631 // Scan for a constant 1632 uint i; 1633 for( i = 1; i < phi->req()-1; i++ ) { 1634 Node *n = phi->in(i); 1635 if( !n ) return NULL; 1636 if( phase->type(n) == Type::TOP ) return NULL; 1637 if( n->Opcode() == Op_ConP || n->Opcode() == Op_ConN || n->Opcode() == Op_ConNKlass ) 1638 break; 1639 } 1640 if( i >= phi->req() ) // Only split for constants 1641 return NULL; 1642 1643 Node *val = phi->in(i); // Constant to split for 1644 uint hit = 0; // Number of times it occurs 1645 Node *r = phi->region(); 1646 1647 for( ; i < phi->req(); i++ ){ // Count occurrences of constant 1648 Node *n = phi->in(i); 1649 if( !n ) return NULL; 1650 if( phase->type(n) == Type::TOP ) return NULL; 1651 if( phi->in(i) == val ) { 1652 hit++; 1653 if (PhaseIdealLoop::find_predicate(r->in(i)) != NULL) { 1654 return NULL; // don't split loop entry path 1655 } 1656 } 1657 } 1658 1659 if( hit <= 1 || // Make sure we find 2 or more 1660 hit == phi->req()-1 ) // and not ALL the same value 1661 return NULL; 1662 1663 // Now start splitting out the flow paths that merge the same value. 1664 // Split first the RegionNode. 1665 PhaseIterGVN *igvn = phase->is_IterGVN(); 1666 RegionNode *newr = new RegionNode(hit+1); 1667 split_once(igvn, phi, val, r, newr); 1668 1669 // Now split all other Phis than this one 1670 for (DUIterator_Fast kmax, k = r->fast_outs(kmax); k < kmax; k++) { 1671 Node* phi2 = r->fast_out(k); 1672 if( phi2->is_Phi() && phi2->as_Phi() != phi ) { 1673 PhiNode *newphi = PhiNode::make_blank(newr, phi2); 1674 split_once(igvn, phi, val, phi2, newphi); 1675 } 1676 } 1677 1678 // Clean up this guy 1679 igvn->hash_delete(phi); 1680 for( i = phi->req()-1; i > 0; i-- ) { 1681 if( phi->in(i) == val ) { 1682 phi->del_req(i); 1683 } 1684 } 1685 phi->add_req(val); 1686 1687 return phi; 1688 } 1689 1690 //============================================================================= 1691 //------------------------------simple_data_loop_check------------------------- 1692 // Try to determining if the phi node in a simple safe/unsafe data loop. 1693 // Returns: 1694 // enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop }; 1695 // Safe - safe case when the phi and it's inputs reference only safe data 1696 // nodes; 1697 // Unsafe - the phi and it's inputs reference unsafe data nodes but there 1698 // is no reference back to the phi - need a graph walk 1699 // to determine if it is in a loop; 1700 // UnsafeLoop - unsafe case when the phi references itself directly or through 1701 // unsafe data node. 1702 // Note: a safe data node is a node which could/never reference itself during 1703 // GVN transformations. For now it is Con, Proj, Phi, CastPP, CheckCastPP. 1704 // I mark Phi nodes as safe node not only because they can reference itself 1705 // but also to prevent mistaking the fallthrough case inside an outer loop 1706 // as dead loop when the phi references itselfs through an other phi. 1707 PhiNode::LoopSafety PhiNode::simple_data_loop_check(Node *in) const { 1708 // It is unsafe loop if the phi node references itself directly. 1709 if (in == (Node*)this) 1710 return UnsafeLoop; // Unsafe loop 1711 // Unsafe loop if the phi node references itself through an unsafe data node. 1712 // Exclude cases with null inputs or data nodes which could reference 1713 // itself (safe for dead loops). 1714 if (in != NULL && !in->is_dead_loop_safe()) { 1715 // Check inputs of phi's inputs also. 1716 // It is much less expensive then full graph walk. 1717 uint cnt = in->req(); 1718 uint i = (in->is_Proj() && !in->is_CFG()) ? 0 : 1; 1719 for (; i < cnt; ++i) { 1720 Node* m = in->in(i); 1721 if (m == (Node*)this) 1722 return UnsafeLoop; // Unsafe loop 1723 if (m != NULL && !m->is_dead_loop_safe()) { 1724 // Check the most common case (about 30% of all cases): 1725 // phi->Load/Store->AddP->(ConP ConP Con)/(Parm Parm Con). 1726 Node *m1 = (m->is_AddP() && m->req() > 3) ? m->in(1) : NULL; 1727 if (m1 == (Node*)this) 1728 return UnsafeLoop; // Unsafe loop 1729 if (m1 != NULL && m1 == m->in(2) && 1730 m1->is_dead_loop_safe() && m->in(3)->is_Con()) { 1731 continue; // Safe case 1732 } 1733 // The phi references an unsafe node - need full analysis. 1734 return Unsafe; 1735 } 1736 } 1737 } 1738 return Safe; // Safe case - we can optimize the phi node. 1739 } 1740 1741 //------------------------------is_unsafe_data_reference----------------------- 1742 // If phi can be reached through the data input - it is data loop. 1743 bool PhiNode::is_unsafe_data_reference(Node *in) const { 1744 assert(req() > 1, ""); 1745 // First, check simple cases when phi references itself directly or 1746 // through an other node. 1747 LoopSafety safety = simple_data_loop_check(in); 1748 if (safety == UnsafeLoop) 1749 return true; // phi references itself - unsafe loop 1750 else if (safety == Safe) 1751 return false; // Safe case - phi could be replaced with the unique input. 1752 1753 // Unsafe case when we should go through data graph to determine 1754 // if the phi references itself. 1755 1756 ResourceMark rm; 1757 1758 Arena *a = Thread::current()->resource_area(); 1759 Node_List nstack(a); 1760 VectorSet visited(a); 1761 1762 nstack.push(in); // Start with unique input. 1763 visited.set(in->_idx); 1764 while (nstack.size() != 0) { 1765 Node* n = nstack.pop(); 1766 uint cnt = n->req(); 1767 uint i = (n->is_Proj() && !n->is_CFG()) ? 0 : 1; 1768 for (; i < cnt; i++) { 1769 Node* m = n->in(i); 1770 if (m == (Node*)this) { 1771 return true; // Data loop 1772 } 1773 if (m != NULL && !m->is_dead_loop_safe()) { // Only look for unsafe cases. 1774 if (!visited.test_set(m->_idx)) 1775 nstack.push(m); 1776 } 1777 } 1778 } 1779 return false; // The phi is not reachable from its inputs 1780 } 1781 1782 1783 //------------------------------Ideal------------------------------------------ 1784 // Return a node which is more "ideal" than the current node. Must preserve 1785 // the CFG, but we can still strip out dead paths. 1786 Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1787 // The next should never happen after 6297035 fix. 1788 if( is_copy() ) // Already degraded to a Copy ? 1789 return NULL; // No change 1790 1791 Node *r = in(0); // RegionNode 1792 assert(r->in(0) == NULL || !r->in(0)->is_Root(), "not a specially hidden merge"); 1793 1794 // Note: During parsing, phis are often transformed before their regions. 1795 // This means we have to use type_or_null to defend against untyped regions. 1796 if( phase->type_or_null(r) == Type::TOP ) // Dead code? 1797 return NULL; // No change 1798 1799 Node *top = phase->C->top(); 1800 bool new_phi = (outcnt() == 0); // transforming new Phi 1801 // No change for igvn if new phi is not hooked 1802 if (new_phi && can_reshape) 1803 return NULL; 1804 1805 // The are 2 situations when only one valid phi's input is left 1806 // (in addition to Region input). 1807 // One: region is not loop - replace phi with this input. 1808 // Two: region is loop - replace phi with top since this data path is dead 1809 // and we need to break the dead data loop. 1810 Node* progress = NULL; // Record if any progress made 1811 for( uint j = 1; j < req(); ++j ){ // For all paths in 1812 // Check unreachable control paths 1813 Node* rc = r->in(j); 1814 Node* n = in(j); // Get the input 1815 if (rc == NULL || phase->type(rc) == Type::TOP) { 1816 if (n != top) { // Not already top? 1817 PhaseIterGVN *igvn = phase->is_IterGVN(); 1818 if (can_reshape && igvn != NULL) { 1819 igvn->_worklist.push(r); 1820 } 1821 // Nuke it down 1822 if (can_reshape) { 1823 set_req_X(j, top, igvn); 1824 } else { 1825 set_req(j, top); 1826 } 1827 progress = this; // Record progress 1828 } 1829 } 1830 } 1831 1832 if (can_reshape && outcnt() == 0) { 1833 // set_req() above may kill outputs if Phi is referenced 1834 // only by itself on the dead (top) control path. 1835 return top; 1836 } 1837 1838 bool uncasted = false; 1839 Node* uin = unique_input(phase, false); 1840 if (uin == NULL && can_reshape) { 1841 uncasted = true; 1842 uin = unique_input(phase, true); 1843 } 1844 if (uin == top) { // Simplest case: no alive inputs. 1845 if (can_reshape) // IGVN transformation 1846 return top; 1847 else 1848 return NULL; // Identity will return TOP 1849 } else if (uin != NULL) { 1850 // Only one not-NULL unique input path is left. 1851 // Determine if this input is backedge of a loop. 1852 // (Skip new phis which have no uses and dead regions). 1853 if (outcnt() > 0 && r->in(0) != NULL) { 1854 // First, take the short cut when we know it is a loop and 1855 // the EntryControl data path is dead. 1856 // Loop node may have only one input because entry path 1857 // is removed in PhaseIdealLoop::Dominators(). 1858 assert(!r->is_Loop() || r->req() <= 3, "Loop node should have 3 or less inputs"); 1859 bool is_loop = (r->is_Loop() && r->req() == 3); 1860 // Then, check if there is a data loop when phi references itself directly 1861 // or through other data nodes. 1862 if ((is_loop && !uin->eqv_uncast(in(LoopNode::EntryControl))) || 1863 (!is_loop && is_unsafe_data_reference(uin))) { 1864 // Break this data loop to avoid creation of a dead loop. 1865 if (can_reshape) { 1866 return top; 1867 } else { 1868 // We can't return top if we are in Parse phase - cut inputs only 1869 // let Identity to handle the case. 1870 replace_edge(uin, top); 1871 return NULL; 1872 } 1873 } 1874 } 1875 1876 if (uncasted) { 1877 // Add cast nodes between the phi to be removed and its unique input. 1878 // Wait until after parsing for the type information to propagate from the casts. 1879 assert(can_reshape, "Invalid during parsing"); 1880 const Type* phi_type = bottom_type(); 1881 assert(phi_type->isa_int() || phi_type->isa_ptr(), "bad phi type"); 1882 // Add casts to carry the control dependency of the Phi that is 1883 // going away 1884 Node* cast = NULL; 1885 if (phi_type->isa_int()) { 1886 cast = ConstraintCastNode::make_cast(Op_CastII, r, uin, phi_type, true); 1887 } else { 1888 const Type* uin_type = phase->type(uin); 1889 if (!phi_type->isa_oopptr() && !uin_type->isa_oopptr()) { 1890 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, phi_type, true); 1891 } else { 1892 // Use a CastPP for a cast to not null and a CheckCastPP for 1893 // a cast to a new klass (and both if both null-ness and 1894 // klass change). 1895 1896 // If the type of phi is not null but the type of uin may be 1897 // null, uin's type must be casted to not null 1898 if (phi_type->join(TypePtr::NOTNULL) == phi_type->remove_speculative() && 1899 uin_type->join(TypePtr::NOTNULL) != uin_type->remove_speculative()) { 1900 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, TypePtr::NOTNULL, true); 1901 } 1902 1903 // If the type of phi and uin, both casted to not null, 1904 // differ the klass of uin must be (check)cast'ed to match 1905 // that of phi 1906 if (phi_type->join_speculative(TypePtr::NOTNULL) != uin_type->join_speculative(TypePtr::NOTNULL)) { 1907 Node* n = uin; 1908 if (cast != NULL) { 1909 cast = phase->transform(cast); 1910 n = cast; 1911 } 1912 cast = ConstraintCastNode::make_cast(Op_CheckCastPP, r, n, phi_type, true); 1913 } 1914 if (cast == NULL) { 1915 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, phi_type, true); 1916 } 1917 } 1918 } 1919 assert(cast != NULL, "cast should be set"); 1920 cast = phase->transform(cast); 1921 // set all inputs to the new cast(s) so the Phi is removed by Identity 1922 PhaseIterGVN* igvn = phase->is_IterGVN(); 1923 for (uint i = 1; i < req(); i++) { 1924 set_req_X(i, cast, igvn); 1925 } 1926 uin = cast; 1927 } 1928 1929 // One unique input. 1930 debug_only(Node* ident = Identity(phase)); 1931 // The unique input must eventually be detected by the Identity call. 1932 #ifdef ASSERT 1933 if (ident != uin && !ident->is_top()) { 1934 // print this output before failing assert 1935 r->dump(3); 1936 this->dump(3); 1937 ident->dump(); 1938 uin->dump(); 1939 } 1940 #endif 1941 assert(ident == uin || ident->is_top(), "Identity must clean this up"); 1942 return NULL; 1943 } 1944 1945 Node* opt = NULL; 1946 int true_path = is_diamond_phi(); 1947 if( true_path != 0 ) { 1948 // Check for CMove'ing identity. If it would be unsafe, 1949 // handle it here. In the safe case, let Identity handle it. 1950 Node* unsafe_id = is_cmove_id(phase, true_path); 1951 if( unsafe_id != NULL && is_unsafe_data_reference(unsafe_id) ) 1952 opt = unsafe_id; 1953 1954 // Check for simple convert-to-boolean pattern 1955 if( opt == NULL ) 1956 opt = is_x2logic(phase, this, true_path); 1957 1958 // Check for absolute value 1959 if( opt == NULL ) 1960 opt = is_absolute(phase, this, true_path); 1961 1962 // Check for conditional add 1963 if( opt == NULL && can_reshape ) 1964 opt = is_cond_add(phase, this, true_path); 1965 1966 // These 4 optimizations could subsume the phi: 1967 // have to check for a dead data loop creation. 1968 if( opt != NULL ) { 1969 if( opt == unsafe_id || is_unsafe_data_reference(opt) ) { 1970 // Found dead loop. 1971 if( can_reshape ) 1972 return top; 1973 // We can't return top if we are in Parse phase - cut inputs only 1974 // to stop further optimizations for this phi. Identity will return TOP. 1975 assert(req() == 3, "only diamond merge phi here"); 1976 set_req(1, top); 1977 set_req(2, top); 1978 return NULL; 1979 } else { 1980 return opt; 1981 } 1982 } 1983 } 1984 1985 // Check for merging identical values and split flow paths 1986 if (can_reshape) { 1987 opt = split_flow_path(phase, this); 1988 // This optimization only modifies phi - don't need to check for dead loop. 1989 assert(opt == NULL || phase->eqv(opt, this), "do not elide phi"); 1990 if (opt != NULL) return opt; 1991 } 1992 1993 if (in(1) != NULL && in(1)->Opcode() == Op_AddP && can_reshape) { 1994 // Try to undo Phi of AddP: 1995 // (Phi (AddP base base y) (AddP base2 base2 y)) 1996 // becomes: 1997 // newbase := (Phi base base2) 1998 // (AddP newbase newbase y) 1999 // 2000 // This occurs as a result of unsuccessful split_thru_phi and 2001 // interferes with taking advantage of addressing modes. See the 2002 // clone_shift_expressions code in matcher.cpp 2003 Node* addp = in(1); 2004 const Type* type = addp->in(AddPNode::Base)->bottom_type(); 2005 Node* y = addp->in(AddPNode::Offset); 2006 if (y != NULL && addp->in(AddPNode::Base) == addp->in(AddPNode::Address)) { 2007 // make sure that all the inputs are similar to the first one, 2008 // i.e. AddP with base == address and same offset as first AddP 2009 bool doit = true; 2010 for (uint i = 2; i < req(); i++) { 2011 if (in(i) == NULL || 2012 in(i)->Opcode() != Op_AddP || 2013 in(i)->in(AddPNode::Base) != in(i)->in(AddPNode::Address) || 2014 in(i)->in(AddPNode::Offset) != y) { 2015 doit = false; 2016 break; 2017 } 2018 // Accumulate type for resulting Phi 2019 type = type->meet_speculative(in(i)->in(AddPNode::Base)->bottom_type()); 2020 } 2021 Node* base = NULL; 2022 if (doit) { 2023 // Check for neighboring AddP nodes in a tree. 2024 // If they have a base, use that it. 2025 for (DUIterator_Fast kmax, k = this->fast_outs(kmax); k < kmax; k++) { 2026 Node* u = this->fast_out(k); 2027 if (u->is_AddP()) { 2028 Node* base2 = u->in(AddPNode::Base); 2029 if (base2 != NULL && !base2->is_top()) { 2030 if (base == NULL) 2031 base = base2; 2032 else if (base != base2) 2033 { doit = false; break; } 2034 } 2035 } 2036 } 2037 } 2038 if (doit) { 2039 if (base == NULL) { 2040 base = new PhiNode(in(0), type, NULL); 2041 for (uint i = 1; i < req(); i++) { 2042 base->init_req(i, in(i)->in(AddPNode::Base)); 2043 } 2044 phase->is_IterGVN()->register_new_node_with_optimizer(base); 2045 } 2046 return new AddPNode(base, base, y); 2047 } 2048 } 2049 } 2050 2051 // Split phis through memory merges, so that the memory merges will go away. 2052 // Piggy-back this transformation on the search for a unique input.... 2053 // It will be as if the merged memory is the unique value of the phi. 2054 // (Do not attempt this optimization unless parsing is complete. 2055 // It would make the parser's memory-merge logic sick.) 2056 // (MergeMemNode is not dead_loop_safe - need to check for dead loop.) 2057 if (progress == NULL && can_reshape && type() == Type::MEMORY) { 2058 // see if this phi should be sliced 2059 uint merge_width = 0; 2060 bool saw_self = false; 2061 for( uint i=1; i<req(); ++i ) {// For all paths in 2062 Node *ii = in(i); 2063 // TOP inputs should not be counted as safe inputs because if the 2064 // Phi references itself through all other inputs then splitting the 2065 // Phi through memory merges would create dead loop at later stage. 2066 if (ii == top) { 2067 return NULL; // Delay optimization until graph is cleaned. 2068 } 2069 if (ii->is_MergeMem()) { 2070 MergeMemNode* n = ii->as_MergeMem(); 2071 merge_width = MAX2(merge_width, n->req()); 2072 saw_self = saw_self || phase->eqv(n->base_memory(), this); 2073 } 2074 } 2075 2076 // This restriction is temporarily necessary to ensure termination: 2077 if (!saw_self && adr_type() == TypePtr::BOTTOM) merge_width = 0; 2078 2079 if (merge_width > Compile::AliasIdxRaw) { 2080 // found at least one non-empty MergeMem 2081 const TypePtr* at = adr_type(); 2082 if (at != TypePtr::BOTTOM) { 2083 // Patch the existing phi to select an input from the merge: 2084 // Phi:AT1(...MergeMem(m0, m1, m2)...) into 2085 // Phi:AT1(...m1...) 2086 int alias_idx = phase->C->get_alias_index(at); 2087 for (uint i=1; i<req(); ++i) { 2088 Node *ii = in(i); 2089 if (ii->is_MergeMem()) { 2090 MergeMemNode* n = ii->as_MergeMem(); 2091 // compress paths and change unreachable cycles to TOP 2092 // If not, we can update the input infinitely along a MergeMem cycle 2093 // Equivalent code is in MemNode::Ideal_common 2094 Node *m = phase->transform(n); 2095 if (outcnt() == 0) { // Above transform() may kill us! 2096 return top; 2097 } 2098 // If transformed to a MergeMem, get the desired slice 2099 // Otherwise the returned node represents memory for every slice 2100 Node *new_mem = (m->is_MergeMem()) ? 2101 m->as_MergeMem()->memory_at(alias_idx) : m; 2102 // Update input if it is progress over what we have now 2103 if (new_mem != ii) { 2104 set_req(i, new_mem); 2105 progress = this; 2106 } 2107 } 2108 } 2109 } else { 2110 // We know that at least one MergeMem->base_memory() == this 2111 // (saw_self == true). If all other inputs also references this phi 2112 // (directly or through data nodes) - it is dead loop. 2113 bool saw_safe_input = false; 2114 for (uint j = 1; j < req(); ++j) { 2115 Node *n = in(j); 2116 if (n->is_MergeMem() && n->as_MergeMem()->base_memory() == this) 2117 continue; // skip known cases 2118 if (!is_unsafe_data_reference(n)) { 2119 saw_safe_input = true; // found safe input 2120 break; 2121 } 2122 } 2123 if (!saw_safe_input) 2124 return top; // all inputs reference back to this phi - dead loop 2125 2126 // Phi(...MergeMem(m0, m1:AT1, m2:AT2)...) into 2127 // MergeMem(Phi(...m0...), Phi:AT1(...m1...), Phi:AT2(...m2...)) 2128 PhaseIterGVN *igvn = phase->is_IterGVN(); 2129 Node* hook = new Node(1); 2130 PhiNode* new_base = (PhiNode*) clone(); 2131 // Must eagerly register phis, since they participate in loops. 2132 if (igvn) { 2133 igvn->register_new_node_with_optimizer(new_base); 2134 hook->add_req(new_base); 2135 } 2136 MergeMemNode* result = MergeMemNode::make(new_base); 2137 for (uint i = 1; i < req(); ++i) { 2138 Node *ii = in(i); 2139 if (ii->is_MergeMem()) { 2140 MergeMemNode* n = ii->as_MergeMem(); 2141 for (MergeMemStream mms(result, n); mms.next_non_empty2(); ) { 2142 // If we have not seen this slice yet, make a phi for it. 2143 bool made_new_phi = false; 2144 if (mms.is_empty()) { 2145 Node* new_phi = new_base->slice_memory(mms.adr_type(phase->C)); 2146 made_new_phi = true; 2147 if (igvn) { 2148 igvn->register_new_node_with_optimizer(new_phi); 2149 hook->add_req(new_phi); 2150 } 2151 mms.set_memory(new_phi); 2152 } 2153 Node* phi = mms.memory(); 2154 assert(made_new_phi || phi->in(i) == n, "replace the i-th merge by a slice"); 2155 phi->set_req(i, mms.memory2()); 2156 } 2157 } 2158 } 2159 // Distribute all self-loops. 2160 { // (Extra braces to hide mms.) 2161 for (MergeMemStream mms(result); mms.next_non_empty(); ) { 2162 Node* phi = mms.memory(); 2163 for (uint i = 1; i < req(); ++i) { 2164 if (phi->in(i) == this) phi->set_req(i, phi); 2165 } 2166 } 2167 } 2168 // now transform the new nodes, and return the mergemem 2169 for (MergeMemStream mms(result); mms.next_non_empty(); ) { 2170 Node* phi = mms.memory(); 2171 mms.set_memory(phase->transform(phi)); 2172 } 2173 if (igvn) { // Unhook. 2174 igvn->hash_delete(hook); 2175 for (uint i = 1; i < hook->req(); i++) { 2176 hook->set_req(i, NULL); 2177 } 2178 } 2179 // Replace self with the result. 2180 return result; 2181 } 2182 } 2183 // 2184 // Other optimizations on the memory chain 2185 // 2186 const TypePtr* at = adr_type(); 2187 for( uint i=1; i<req(); ++i ) {// For all paths in 2188 Node *ii = in(i); 2189 Node *new_in = MemNode::optimize_memory_chain(ii, at, NULL, phase); 2190 if (ii != new_in ) { 2191 set_req(i, new_in); 2192 progress = this; 2193 } 2194 } 2195 } 2196 2197 #ifdef _LP64 2198 // Push DecodeN/DecodeNKlass down through phi. 2199 // The rest of phi graph will transform by split EncodeP node though phis up. 2200 if ((UseCompressedOops || UseCompressedClassPointers) && can_reshape && progress == NULL) { 2201 bool may_push = true; 2202 bool has_decodeN = false; 2203 bool is_decodeN = false; 2204 for (uint i=1; i<req(); ++i) {// For all paths in 2205 Node *ii = in(i); 2206 if (ii->is_DecodeNarrowPtr() && ii->bottom_type() == bottom_type()) { 2207 // Do optimization if a non dead path exist. 2208 if (ii->in(1)->bottom_type() != Type::TOP) { 2209 has_decodeN = true; 2210 is_decodeN = ii->is_DecodeN(); 2211 } 2212 } else if (!ii->is_Phi()) { 2213 may_push = false; 2214 } 2215 } 2216 2217 if (has_decodeN && may_push) { 2218 PhaseIterGVN *igvn = phase->is_IterGVN(); 2219 // Make narrow type for new phi. 2220 const Type* narrow_t; 2221 if (is_decodeN) { 2222 narrow_t = TypeNarrowOop::make(this->bottom_type()->is_ptr()); 2223 } else { 2224 narrow_t = TypeNarrowKlass::make(this->bottom_type()->is_ptr()); 2225 } 2226 PhiNode* new_phi = new PhiNode(r, narrow_t); 2227 uint orig_cnt = req(); 2228 for (uint i=1; i<req(); ++i) {// For all paths in 2229 Node *ii = in(i); 2230 Node* new_ii = NULL; 2231 if (ii->is_DecodeNarrowPtr()) { 2232 assert(ii->bottom_type() == bottom_type(), "sanity"); 2233 new_ii = ii->in(1); 2234 } else { 2235 assert(ii->is_Phi(), "sanity"); 2236 if (ii->as_Phi() == this) { 2237 new_ii = new_phi; 2238 } else { 2239 if (is_decodeN) { 2240 new_ii = new EncodePNode(ii, narrow_t); 2241 } else { 2242 new_ii = new EncodePKlassNode(ii, narrow_t); 2243 } 2244 igvn->register_new_node_with_optimizer(new_ii); 2245 } 2246 } 2247 new_phi->set_req(i, new_ii); 2248 } 2249 igvn->register_new_node_with_optimizer(new_phi, this); 2250 if (is_decodeN) { 2251 progress = new DecodeNNode(new_phi, bottom_type()); 2252 } else { 2253 progress = new DecodeNKlassNode(new_phi, bottom_type()); 2254 } 2255 } 2256 } 2257 #endif 2258 2259 return progress; // Return any progress 2260 } 2261 2262 //------------------------------is_tripcount----------------------------------- 2263 bool PhiNode::is_tripcount() const { 2264 return (in(0) != NULL && in(0)->is_CountedLoop() && 2265 in(0)->as_CountedLoop()->phi() == this); 2266 } 2267 2268 //------------------------------out_RegMask------------------------------------ 2269 const RegMask &PhiNode::in_RegMask(uint i) const { 2270 return i ? out_RegMask() : RegMask::Empty; 2271 } 2272 2273 const RegMask &PhiNode::out_RegMask() const { 2274 uint ideal_reg = _type->ideal_reg(); 2275 assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" ); 2276 if( ideal_reg == 0 ) return RegMask::Empty; 2277 assert(ideal_reg != Op_RegFlags, "flags register is not spillable"); 2278 return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]); 2279 } 2280 2281 #ifndef PRODUCT 2282 void PhiNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { 2283 // For a PhiNode, the set of related nodes includes all inputs till level 2, 2284 // and all outputs till level 1. In compact mode, inputs till level 1 are 2285 // collected. 2286 this->collect_nodes(in_rel, compact ? 1 : 2, false, false); 2287 this->collect_nodes(out_rel, -1, false, false); 2288 } 2289 2290 void PhiNode::dump_spec(outputStream *st) const { 2291 TypeNode::dump_spec(st); 2292 if (is_tripcount()) { 2293 st->print(" #tripcount"); 2294 } 2295 } 2296 #endif 2297 2298 2299 //============================================================================= 2300 const Type* GotoNode::Value(PhaseGVN* phase) const { 2301 // If the input is reachable, then we are executed. 2302 // If the input is not reachable, then we are not executed. 2303 return phase->type(in(0)); 2304 } 2305 2306 Node* GotoNode::Identity(PhaseGVN* phase) { 2307 return in(0); // Simple copy of incoming control 2308 } 2309 2310 const RegMask &GotoNode::out_RegMask() const { 2311 return RegMask::Empty; 2312 } 2313 2314 #ifndef PRODUCT 2315 //-----------------------------related----------------------------------------- 2316 // The related nodes of a GotoNode are all inputs at level 1, as well as the 2317 // outputs at level 1. This is regardless of compact mode. 2318 void GotoNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { 2319 this->collect_nodes(in_rel, 1, false, false); 2320 this->collect_nodes(out_rel, -1, false, false); 2321 } 2322 #endif 2323 2324 2325 //============================================================================= 2326 const RegMask &JumpNode::out_RegMask() const { 2327 return RegMask::Empty; 2328 } 2329 2330 #ifndef PRODUCT 2331 //-----------------------------related----------------------------------------- 2332 // The related nodes of a JumpNode are all inputs at level 1, as well as the 2333 // outputs at level 2 (to include actual jump targets beyond projection nodes). 2334 // This is regardless of compact mode. 2335 void JumpNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { 2336 this->collect_nodes(in_rel, 1, false, false); 2337 this->collect_nodes(out_rel, -2, false, false); 2338 } 2339 #endif 2340 2341 //============================================================================= 2342 const RegMask &JProjNode::out_RegMask() const { 2343 return RegMask::Empty; 2344 } 2345 2346 //============================================================================= 2347 const RegMask &CProjNode::out_RegMask() const { 2348 return RegMask::Empty; 2349 } 2350 2351 2352 2353 //============================================================================= 2354 2355 uint PCTableNode::hash() const { return Node::hash() + _size; } 2356 uint PCTableNode::cmp( const Node &n ) const 2357 { return _size == ((PCTableNode&)n)._size; } 2358 2359 const Type *PCTableNode::bottom_type() const { 2360 const Type** f = TypeTuple::fields(_size); 2361 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; 2362 return TypeTuple::make(_size, f); 2363 } 2364 2365 //------------------------------Value------------------------------------------ 2366 // Compute the type of the PCTableNode. If reachable it is a tuple of 2367 // Control, otherwise the table targets are not reachable 2368 const Type* PCTableNode::Value(PhaseGVN* phase) const { 2369 if( phase->type(in(0)) == Type::CONTROL ) 2370 return bottom_type(); 2371 return Type::TOP; // All paths dead? Then so are we 2372 } 2373 2374 //------------------------------Ideal------------------------------------------ 2375 // Return a node which is more "ideal" than the current node. Strip out 2376 // control copies 2377 Node *PCTableNode::Ideal(PhaseGVN *phase, bool can_reshape) { 2378 return remove_dead_region(phase, can_reshape) ? this : NULL; 2379 } 2380 2381 //============================================================================= 2382 uint JumpProjNode::hash() const { 2383 return Node::hash() + _dest_bci; 2384 } 2385 2386 uint JumpProjNode::cmp( const Node &n ) const { 2387 return ProjNode::cmp(n) && 2388 _dest_bci == ((JumpProjNode&)n)._dest_bci; 2389 } 2390 2391 #ifndef PRODUCT 2392 void JumpProjNode::dump_spec(outputStream *st) const { 2393 ProjNode::dump_spec(st); 2394 st->print("@bci %d ",_dest_bci); 2395 } 2396 2397 void JumpProjNode::dump_compact_spec(outputStream *st) const { 2398 ProjNode::dump_compact_spec(st); 2399 st->print("(%d)%d@%d", _switch_val, _proj_no, _dest_bci); 2400 } 2401 2402 void JumpProjNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { 2403 // The related nodes of a JumpProjNode are its inputs and outputs at level 1. 2404 this->collect_nodes(in_rel, 1, false, false); 2405 this->collect_nodes(out_rel, -1, false, false); 2406 } 2407 #endif 2408 2409 //============================================================================= 2410 //------------------------------Value------------------------------------------ 2411 // Check for being unreachable, or for coming from a Rethrow. Rethrow's cannot 2412 // have the default "fall_through_index" path. 2413 const Type* CatchNode::Value(PhaseGVN* phase) const { 2414 // Unreachable? Then so are all paths from here. 2415 if( phase->type(in(0)) == Type::TOP ) return Type::TOP; 2416 // First assume all paths are reachable 2417 const Type** f = TypeTuple::fields(_size); 2418 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; 2419 // Identify cases that will always throw an exception 2420 // () rethrow call 2421 // () virtual or interface call with NULL receiver 2422 // () call is a check cast with incompatible arguments 2423 if( in(1)->is_Proj() ) { 2424 Node *i10 = in(1)->in(0); 2425 if( i10->is_Call() ) { 2426 CallNode *call = i10->as_Call(); 2427 // Rethrows always throw exceptions, never return 2428 if (call->entry_point() == OptoRuntime::rethrow_stub()) { 2429 f[CatchProjNode::fall_through_index] = Type::TOP; 2430 } else if( call->req() > TypeFunc::Parms ) { 2431 const Type *arg0 = phase->type( call->in(TypeFunc::Parms) ); 2432 // Check for null receiver to virtual or interface calls 2433 if( call->is_CallDynamicJava() && 2434 arg0->higher_equal(TypePtr::NULL_PTR) ) { 2435 f[CatchProjNode::fall_through_index] = Type::TOP; 2436 } 2437 } // End of if not a runtime stub 2438 } // End of if have call above me 2439 } // End of slot 1 is not a projection 2440 return TypeTuple::make(_size, f); 2441 } 2442 2443 //============================================================================= 2444 uint CatchProjNode::hash() const { 2445 return Node::hash() + _handler_bci; 2446 } 2447 2448 2449 uint CatchProjNode::cmp( const Node &n ) const { 2450 return ProjNode::cmp(n) && 2451 _handler_bci == ((CatchProjNode&)n)._handler_bci; 2452 } 2453 2454 2455 //------------------------------Identity--------------------------------------- 2456 // If only 1 target is possible, choose it if it is the main control 2457 Node* CatchProjNode::Identity(PhaseGVN* phase) { 2458 // If my value is control and no other value is, then treat as ID 2459 const TypeTuple *t = phase->type(in(0))->is_tuple(); 2460 if (t->field_at(_con) != Type::CONTROL) return this; 2461 // If we remove the last CatchProj and elide the Catch/CatchProj, then we 2462 // also remove any exception table entry. Thus we must know the call 2463 // feeding the Catch will not really throw an exception. This is ok for 2464 // the main fall-thru control (happens when we know a call can never throw 2465 // an exception) or for "rethrow", because a further optimization will 2466 // yank the rethrow (happens when we inline a function that can throw an 2467 // exception and the caller has no handler). Not legal, e.g., for passing 2468 // a NULL receiver to a v-call, or passing bad types to a slow-check-cast. 2469 // These cases MUST throw an exception via the runtime system, so the VM 2470 // will be looking for a table entry. 2471 Node *proj = in(0)->in(1); // Expect a proj feeding CatchNode 2472 CallNode *call; 2473 if (_con != TypeFunc::Control && // Bail out if not the main control. 2474 !(proj->is_Proj() && // AND NOT a rethrow 2475 proj->in(0)->is_Call() && 2476 (call = proj->in(0)->as_Call()) && 2477 call->entry_point() == OptoRuntime::rethrow_stub())) 2478 return this; 2479 2480 // Search for any other path being control 2481 for (uint i = 0; i < t->cnt(); i++) { 2482 if (i != _con && t->field_at(i) == Type::CONTROL) 2483 return this; 2484 } 2485 // Only my path is possible; I am identity on control to the jump 2486 return in(0)->in(0); 2487 } 2488 2489 2490 #ifndef PRODUCT 2491 void CatchProjNode::dump_spec(outputStream *st) const { 2492 ProjNode::dump_spec(st); 2493 st->print("@bci %d ",_handler_bci); 2494 } 2495 #endif 2496 2497 //============================================================================= 2498 //------------------------------Identity--------------------------------------- 2499 // Check for CreateEx being Identity. 2500 Node* CreateExNode::Identity(PhaseGVN* phase) { 2501 if( phase->type(in(1)) == Type::TOP ) return in(1); 2502 if( phase->type(in(0)) == Type::TOP ) return in(0); 2503 // We only come from CatchProj, unless the CatchProj goes away. 2504 // If the CatchProj is optimized away, then we just carry the 2505 // exception oop through. 2506 CallNode *call = in(1)->in(0)->as_Call(); 2507 2508 return ( in(0)->is_CatchProj() && in(0)->in(0)->in(1) == in(1) ) 2509 ? this 2510 : call->in(TypeFunc::Parms); 2511 } 2512 2513 //============================================================================= 2514 //------------------------------Value------------------------------------------ 2515 // Check for being unreachable. 2516 const Type* NeverBranchNode::Value(PhaseGVN* phase) const { 2517 if (!in(0) || in(0)->is_top()) return Type::TOP; 2518 return bottom_type(); 2519 } 2520 2521 //------------------------------Ideal------------------------------------------ 2522 // Check for no longer being part of a loop 2523 Node *NeverBranchNode::Ideal(PhaseGVN *phase, bool can_reshape) { 2524 if (can_reshape && !in(0)->is_Loop()) { 2525 // Dead code elimination can sometimes delete this projection so 2526 // if it's not there, there's nothing to do. 2527 Node* fallthru = proj_out_or_null(0); 2528 if (fallthru != NULL) { 2529 phase->is_IterGVN()->replace_node(fallthru, in(0)); 2530 } 2531 return phase->C->top(); 2532 } 2533 return NULL; 2534 } 2535 2536 #ifndef PRODUCT 2537 void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const { 2538 st->print("%s", Name()); 2539 } 2540 #endif