1 /* 2 * Copyright (c) 1997, 2020, 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 "opto/vectornode.hpp" 47 #include "utilities/vmError.hpp" 48 49 // Portions of code courtesy of Clifford Click 50 51 // Optimization - Graph Style 52 53 //============================================================================= 54 //------------------------------Value------------------------------------------ 55 // Compute the type of the RegionNode. 56 const Type* RegionNode::Value(PhaseGVN* phase) const { 57 for( uint i=1; i<req(); ++i ) { // For all paths in 58 Node *n = in(i); // Get Control source 59 if( !n ) continue; // Missing inputs are TOP 60 if( phase->type(n) == Type::CONTROL ) 61 return Type::CONTROL; 62 } 63 return Type::TOP; // All paths dead? Then so are we 64 } 65 66 //------------------------------Identity--------------------------------------- 67 // Check for Region being Identity. 68 Node* RegionNode::Identity(PhaseGVN* phase) { 69 // Cannot have Region be an identity, even if it has only 1 input. 70 // Phi users cannot have their Region input folded away for them, 71 // since they need to select the proper data input 72 return this; 73 } 74 75 //------------------------------merge_region----------------------------------- 76 // If a Region flows into a Region, merge into one big happy merge. This is 77 // hard to do if there is stuff that has to happen 78 static Node *merge_region(RegionNode *region, PhaseGVN *phase) { 79 if( region->Opcode() != Op_Region ) // Do not do to LoopNodes 80 return NULL; 81 Node *progress = NULL; // Progress flag 82 PhaseIterGVN *igvn = phase->is_IterGVN(); 83 84 uint rreq = region->req(); 85 for( uint i = 1; i < rreq; i++ ) { 86 Node *r = region->in(i); 87 if( r && r->Opcode() == Op_Region && // Found a region? 88 r->in(0) == r && // Not already collapsed? 89 r != region && // Avoid stupid situations 90 r->outcnt() == 2 ) { // Self user and 'region' user only? 91 assert(!r->as_Region()->has_phi(), "no phi users"); 92 if( !progress ) { // No progress 93 if (region->has_phi()) { 94 return NULL; // Only flatten if no Phi users 95 // igvn->hash_delete( phi ); 96 } 97 igvn->hash_delete( region ); 98 progress = region; // Making progress 99 } 100 igvn->hash_delete( r ); 101 102 // Append inputs to 'r' onto 'region' 103 for( uint j = 1; j < r->req(); j++ ) { 104 // Move an input from 'r' to 'region' 105 region->add_req(r->in(j)); 106 r->set_req(j, phase->C->top()); 107 // Update phis of 'region' 108 //for( uint k = 0; k < max; k++ ) { 109 // Node *phi = region->out(k); 110 // if( phi->is_Phi() ) { 111 // phi->add_req(phi->in(i)); 112 // } 113 //} 114 115 rreq++; // One more input to Region 116 } // Found a region to merge into Region 117 igvn->_worklist.push(r); 118 // Clobber pointer to the now dead 'r' 119 region->set_req(i, phase->C->top()); 120 } 121 } 122 123 return progress; 124 } 125 126 127 128 //--------------------------------has_phi-------------------------------------- 129 // Helper function: Return any PhiNode that uses this region or NULL 130 PhiNode* RegionNode::has_phi() const { 131 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 132 Node* phi = fast_out(i); 133 if (phi->is_Phi()) { // Check for Phi users 134 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); 135 return phi->as_Phi(); // this one is good enough 136 } 137 } 138 139 return NULL; 140 } 141 142 143 //-----------------------------has_unique_phi---------------------------------- 144 // Helper function: Return the only PhiNode that uses this region or NULL 145 PhiNode* RegionNode::has_unique_phi() const { 146 // Check that only one use is a Phi 147 PhiNode* only_phi = NULL; 148 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 149 Node* phi = fast_out(i); 150 if (phi->is_Phi()) { // Check for Phi users 151 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); 152 if (only_phi == NULL) { 153 only_phi = phi->as_Phi(); 154 } else { 155 return NULL; // multiple phis 156 } 157 } 158 } 159 160 return only_phi; 161 } 162 163 164 //------------------------------check_phi_clipping----------------------------- 165 // Helper function for RegionNode's identification of FP clipping 166 // Check inputs to the Phi 167 static bool check_phi_clipping( PhiNode *phi, ConNode * &min, uint &min_idx, ConNode * &max, uint &max_idx, Node * &val, uint &val_idx ) { 168 min = NULL; 169 max = NULL; 170 val = NULL; 171 min_idx = 0; 172 max_idx = 0; 173 val_idx = 0; 174 uint phi_max = phi->req(); 175 if( phi_max == 4 ) { 176 for( uint j = 1; j < phi_max; ++j ) { 177 Node *n = phi->in(j); 178 int opcode = n->Opcode(); 179 switch( opcode ) { 180 case Op_ConI: 181 { 182 if( min == NULL ) { 183 min = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; 184 min_idx = j; 185 } else { 186 max = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; 187 max_idx = j; 188 if( min->get_int() > max->get_int() ) { 189 // Swap min and max 190 ConNode *temp; 191 uint temp_idx; 192 temp = min; min = max; max = temp; 193 temp_idx = min_idx; min_idx = max_idx; max_idx = temp_idx; 194 } 195 } 196 } 197 break; 198 default: 199 { 200 val = n; 201 val_idx = j; 202 } 203 break; 204 } 205 } 206 } 207 return ( min && max && val && (min->get_int() <= 0) && (max->get_int() >=0) ); 208 } 209 210 211 //------------------------------check_if_clipping------------------------------ 212 // Helper function for RegionNode's identification of FP clipping 213 // Check that inputs to Region come from two IfNodes, 214 // 215 // If 216 // False True 217 // If | 218 // False True | 219 // | | | 220 // RegionNode_inputs 221 // 222 static bool check_if_clipping( const RegionNode *region, IfNode * &bot_if, IfNode * &top_if ) { 223 top_if = NULL; 224 bot_if = NULL; 225 226 // Check control structure above RegionNode for (if ( if ) ) 227 Node *in1 = region->in(1); 228 Node *in2 = region->in(2); 229 Node *in3 = region->in(3); 230 // Check that all inputs are projections 231 if( in1->is_Proj() && in2->is_Proj() && in3->is_Proj() ) { 232 Node *in10 = in1->in(0); 233 Node *in20 = in2->in(0); 234 Node *in30 = in3->in(0); 235 // Check that #1 and #2 are ifTrue and ifFalse from same If 236 if( in10 != NULL && in10->is_If() && 237 in20 != NULL && in20->is_If() && 238 in30 != NULL && in30->is_If() && in10 == in20 && 239 (in1->Opcode() != in2->Opcode()) ) { 240 Node *in100 = in10->in(0); 241 Node *in1000 = (in100 != NULL && in100->is_Proj()) ? in100->in(0) : NULL; 242 // Check that control for in10 comes from other branch of IF from in3 243 if( in1000 != NULL && in1000->is_If() && 244 in30 == in1000 && (in3->Opcode() != in100->Opcode()) ) { 245 // Control pattern checks 246 top_if = (IfNode*)in1000; 247 bot_if = (IfNode*)in10; 248 } 249 } 250 } 251 252 return (top_if != NULL); 253 } 254 255 256 //------------------------------check_convf2i_clipping------------------------- 257 // Helper function for RegionNode's identification of FP clipping 258 // Verify that the value input to the phi comes from "ConvF2I; LShift; RShift" 259 static bool check_convf2i_clipping( PhiNode *phi, uint idx, ConvF2INode * &convf2i, Node *min, Node *max) { 260 convf2i = NULL; 261 262 // Check for the RShiftNode 263 Node *rshift = phi->in(idx); 264 assert( rshift, "Previous checks ensure phi input is present"); 265 if( rshift->Opcode() != Op_RShiftI ) { return false; } 266 267 // Check for the LShiftNode 268 Node *lshift = rshift->in(1); 269 assert( lshift, "Previous checks ensure phi input is present"); 270 if( lshift->Opcode() != Op_LShiftI ) { return false; } 271 272 // Check for the ConvF2INode 273 Node *conv = lshift->in(1); 274 if( conv->Opcode() != Op_ConvF2I ) { return false; } 275 276 // Check that shift amounts are only to get sign bits set after F2I 277 jint max_cutoff = max->get_int(); 278 jint min_cutoff = min->get_int(); 279 jint left_shift = lshift->in(2)->get_int(); 280 jint right_shift = rshift->in(2)->get_int(); 281 jint max_post_shift = nth_bit(BitsPerJavaInteger - left_shift - 1); 282 if( left_shift != right_shift || 283 0 > left_shift || left_shift >= BitsPerJavaInteger || 284 max_post_shift < max_cutoff || 285 max_post_shift < -min_cutoff ) { 286 // Shifts are necessary but current transformation eliminates them 287 return false; 288 } 289 290 // OK to return the result of ConvF2I without shifting 291 convf2i = (ConvF2INode*)conv; 292 return true; 293 } 294 295 296 //------------------------------check_compare_clipping------------------------- 297 // Helper function for RegionNode's identification of FP clipping 298 static bool check_compare_clipping( bool less_than, IfNode *iff, ConNode *limit, Node * & input ) { 299 Node *i1 = iff->in(1); 300 if ( !i1->is_Bool() ) { return false; } 301 BoolNode *bool1 = i1->as_Bool(); 302 if( less_than && bool1->_test._test != BoolTest::le ) { return false; } 303 else if( !less_than && bool1->_test._test != BoolTest::lt ) { return false; } 304 const Node *cmpF = bool1->in(1); 305 if( cmpF->Opcode() != Op_CmpF ) { return false; } 306 // Test that the float value being compared against 307 // is equivalent to the int value used as a limit 308 Node *nodef = cmpF->in(2); 309 if( nodef->Opcode() != Op_ConF ) { return false; } 310 jfloat conf = nodef->getf(); 311 jint coni = limit->get_int(); 312 if( ((int)conf) != coni ) { return false; } 313 input = cmpF->in(1); 314 return true; 315 } 316 317 //------------------------------is_unreachable_region-------------------------- 318 // Find if the Region node is reachable from the root. 319 bool RegionNode::is_unreachable_region(PhaseGVN *phase) const { 320 assert(req() == 2, ""); 321 322 // First, cut the simple case of fallthrough region when NONE of 323 // region's phis references itself directly or through a data node. 324 uint max = outcnt(); 325 uint i; 326 for (i = 0; i < max; i++) { 327 Node* phi = raw_out(i); 328 if (phi != NULL && phi->is_Phi()) { 329 assert(phase->eqv(phi->in(0), this) && phi->req() == 2, ""); 330 if (phi->outcnt() == 0) 331 continue; // Safe case - no loops 332 if (phi->outcnt() == 1) { 333 Node* u = phi->raw_out(0); 334 // Skip if only one use is an other Phi or Call or Uncommon trap. 335 // It is safe to consider this case as fallthrough. 336 if (u != NULL && (u->is_Phi() || u->is_CFG())) 337 continue; 338 } 339 // Check when phi references itself directly or through an other node. 340 if (phi->as_Phi()->simple_data_loop_check(phi->in(1)) >= PhiNode::Unsafe) 341 break; // Found possible unsafe data loop. 342 } 343 } 344 if (i >= max) 345 return false; // An unsafe case was NOT found - don't need graph walk. 346 347 // Unsafe case - check if the Region node is reachable from root. 348 ResourceMark rm; 349 350 Node_List nstack; 351 VectorSet visited; 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 bool 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; 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 // Looking for phis with identical inputs. If we find one that has 1339 // type TypePtr::BOTTOM, replace the current phi with the bottom phi. 1340 if (phase->is_IterGVN() && type() == Type::MEMORY && adr_type() != 1341 TypePtr::BOTTOM && !adr_type()->is_known_instance()) { 1342 uint phi_len = req(); 1343 Node* phi_reg = region(); 1344 for (DUIterator_Fast imax, i = phi_reg->fast_outs(imax); i < imax; i++) { 1345 Node* u = phi_reg->fast_out(i); 1346 if (u->is_Phi() && u->as_Phi()->type() == Type::MEMORY && 1347 u->adr_type() == TypePtr::BOTTOM && u->in(0) == phi_reg && 1348 u->req() == phi_len) { 1349 for (uint j = 1; j < phi_len; j++) { 1350 if (in(j) != u->in(j)) { 1351 u = NULL; 1352 break; 1353 } 1354 } 1355 if (u != NULL) { 1356 return u; 1357 } 1358 } 1359 } 1360 } 1361 1362 return this; // No identity 1363 } 1364 1365 //-----------------------------unique_input------------------------------------ 1366 // Find the unique value, discounting top, self-loops, and casts. 1367 // Return top if there are no inputs, and self if there are multiple. 1368 Node* PhiNode::unique_input(PhaseTransform* phase, bool uncast) { 1369 // 1) One unique direct input, 1370 // or if uncast is true: 1371 // 2) some of the inputs have an intervening ConstraintCast 1372 // 3) an input is a self loop 1373 // 1374 // 1) input or 2) input or 3) input __ 1375 // / \ / \ \ / \ 1376 // \ / | cast phi cast 1377 // phi \ / / \ / 1378 // phi / -- 1379 1380 Node* r = in(0); // RegionNode 1381 if (r == NULL) return in(1); // Already degraded to a Copy 1382 Node* input = NULL; // The unique direct input (maybe uncasted = ConstraintCasts removed) 1383 1384 for (uint i = 1, cnt = req(); i < cnt; ++i) { 1385 Node* rc = r->in(i); 1386 if (rc == NULL || phase->type(rc) == Type::TOP) 1387 continue; // ignore unreachable control path 1388 Node* n = in(i); 1389 if (n == NULL) 1390 continue; 1391 Node* un = n; 1392 if (uncast) { 1393 #ifdef ASSERT 1394 Node* m = un->uncast(); 1395 #endif 1396 while (un != NULL && un->req() == 2 && un->is_ConstraintCast()) { 1397 Node* next = un->in(1); 1398 if (phase->type(next)->isa_rawptr() && phase->type(un)->isa_oopptr()) { 1399 // risk exposing raw ptr at safepoint 1400 break; 1401 } 1402 un = next; 1403 } 1404 assert(m == un || un->in(1) == m, "Only expected at CheckCastPP from allocation"); 1405 } 1406 if (un == NULL || un == this || phase->type(un) == Type::TOP) { 1407 continue; // ignore if top, or in(i) and "this" are in a data cycle 1408 } 1409 // Check for a unique input (maybe uncasted) 1410 if (input == NULL) { 1411 input = un; 1412 } else if (input != un) { 1413 input = NodeSentinel; // no unique input 1414 } 1415 } 1416 if (input == NULL) { 1417 return phase->C->top(); // no inputs 1418 } 1419 1420 if (input != NodeSentinel) { 1421 return input; // one unique direct input 1422 } 1423 1424 // Nothing. 1425 return NULL; 1426 } 1427 1428 //------------------------------is_x2logic------------------------------------- 1429 // Check for simple convert-to-boolean pattern 1430 // If:(C Bool) Region:(IfF IfT) Phi:(Region 0 1) 1431 // Convert Phi to an ConvIB. 1432 static Node *is_x2logic( PhaseGVN *phase, PhiNode *phi, int true_path ) { 1433 assert(true_path !=0, "only diamond shape graph expected"); 1434 // Convert the true/false index into an expected 0/1 return. 1435 // Map 2->0 and 1->1. 1436 int flipped = 2-true_path; 1437 1438 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1439 // phi->region->if_proj->ifnode->bool->cmp 1440 Node *region = phi->in(0); 1441 Node *iff = region->in(1)->in(0); 1442 BoolNode *b = (BoolNode*)iff->in(1); 1443 const CmpNode *cmp = (CmpNode*)b->in(1); 1444 1445 Node *zero = phi->in(1); 1446 Node *one = phi->in(2); 1447 const Type *tzero = phase->type( zero ); 1448 const Type *tone = phase->type( one ); 1449 1450 // Check for compare vs 0 1451 const Type *tcmp = phase->type(cmp->in(2)); 1452 if( tcmp != TypeInt::ZERO && tcmp != TypePtr::NULL_PTR ) { 1453 // Allow cmp-vs-1 if the other input is bounded by 0-1 1454 if( !(tcmp == TypeInt::ONE && phase->type(cmp->in(1)) == TypeInt::BOOL) ) 1455 return NULL; 1456 flipped = 1-flipped; // Test is vs 1 instead of 0! 1457 } 1458 1459 // Check for setting zero/one opposite expected 1460 if( tzero == TypeInt::ZERO ) { 1461 if( tone == TypeInt::ONE ) { 1462 } else return NULL; 1463 } else if( tzero == TypeInt::ONE ) { 1464 if( tone == TypeInt::ZERO ) { 1465 flipped = 1-flipped; 1466 } else return NULL; 1467 } else return NULL; 1468 1469 // Check for boolean test backwards 1470 if( b->_test._test == BoolTest::ne ) { 1471 } else if( b->_test._test == BoolTest::eq ) { 1472 flipped = 1-flipped; 1473 } else return NULL; 1474 1475 // Build int->bool conversion 1476 Node *n = new Conv2BNode(cmp->in(1)); 1477 if( flipped ) 1478 n = new XorINode( phase->transform(n), phase->intcon(1) ); 1479 1480 return n; 1481 } 1482 1483 //------------------------------is_cond_add------------------------------------ 1484 // Check for simple conditional add pattern: "(P < Q) ? X+Y : X;" 1485 // To be profitable the control flow has to disappear; there can be no other 1486 // values merging here. We replace the test-and-branch with: 1487 // "(sgn(P-Q))&Y) + X". Basically, convert "(P < Q)" into 0 or -1 by 1488 // moving the carry bit from (P-Q) into a register with 'sbb EAX,EAX'. 1489 // Then convert Y to 0-or-Y and finally add. 1490 // This is a key transform for SpecJava _201_compress. 1491 static Node* is_cond_add(PhaseGVN *phase, PhiNode *phi, int true_path) { 1492 assert(true_path !=0, "only diamond shape graph expected"); 1493 1494 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1495 // phi->region->if_proj->ifnode->bool->cmp 1496 RegionNode *region = (RegionNode*)phi->in(0); 1497 Node *iff = region->in(1)->in(0); 1498 BoolNode* b = iff->in(1)->as_Bool(); 1499 const CmpNode *cmp = (CmpNode*)b->in(1); 1500 1501 // Make sure only merging this one phi here 1502 if (region->has_unique_phi() != phi) return NULL; 1503 1504 // Make sure each arm of the diamond has exactly one output, which we assume 1505 // is the region. Otherwise, the control flow won't disappear. 1506 if (region->in(1)->outcnt() != 1) return NULL; 1507 if (region->in(2)->outcnt() != 1) return NULL; 1508 1509 // Check for "(P < Q)" of type signed int 1510 if (b->_test._test != BoolTest::lt) return NULL; 1511 if (cmp->Opcode() != Op_CmpI) return NULL; 1512 1513 Node *p = cmp->in(1); 1514 Node *q = cmp->in(2); 1515 Node *n1 = phi->in( true_path); 1516 Node *n2 = phi->in(3-true_path); 1517 1518 int op = n1->Opcode(); 1519 if( op != Op_AddI // Need zero as additive identity 1520 /*&&op != Op_SubI && 1521 op != Op_AddP && 1522 op != Op_XorI && 1523 op != Op_OrI*/ ) 1524 return NULL; 1525 1526 Node *x = n2; 1527 Node *y = NULL; 1528 if( x == n1->in(1) ) { 1529 y = n1->in(2); 1530 } else if( x == n1->in(2) ) { 1531 y = n1->in(1); 1532 } else return NULL; 1533 1534 // Not so profitable if compare and add are constants 1535 if( q->is_Con() && phase->type(q) != TypeInt::ZERO && y->is_Con() ) 1536 return NULL; 1537 1538 Node *cmplt = phase->transform( new CmpLTMaskNode(p,q) ); 1539 Node *j_and = phase->transform( new AndINode(cmplt,y) ); 1540 return new AddINode(j_and,x); 1541 } 1542 1543 //------------------------------is_absolute------------------------------------ 1544 // Check for absolute value. 1545 static Node* is_absolute( PhaseGVN *phase, PhiNode *phi_root, int true_path) { 1546 assert(true_path !=0, "only diamond shape graph expected"); 1547 1548 int cmp_zero_idx = 0; // Index of compare input where to look for zero 1549 int phi_x_idx = 0; // Index of phi input where to find naked x 1550 1551 // ABS ends with the merge of 2 control flow paths. 1552 // Find the false path from the true path. With only 2 inputs, 3 - x works nicely. 1553 int false_path = 3 - true_path; 1554 1555 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1556 // phi->region->if_proj->ifnode->bool->cmp 1557 BoolNode *bol = phi_root->in(0)->in(1)->in(0)->in(1)->as_Bool(); 1558 Node *cmp = bol->in(1); 1559 1560 // Check bool sense 1561 if (cmp->Opcode() == Op_CmpF || cmp->Opcode() == Op_CmpD) { 1562 switch (bol->_test._test) { 1563 case BoolTest::lt: cmp_zero_idx = 1; phi_x_idx = true_path; break; 1564 case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break; 1565 case BoolTest::gt: cmp_zero_idx = 2; phi_x_idx = true_path; break; 1566 case BoolTest::ge: cmp_zero_idx = 1; phi_x_idx = false_path; break; 1567 default: return NULL; break; 1568 } 1569 } else if (cmp->Opcode() == Op_CmpI || cmp->Opcode() == Op_CmpL) { 1570 switch (bol->_test._test) { 1571 case BoolTest::lt: 1572 case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break; 1573 case BoolTest::gt: 1574 case BoolTest::ge: cmp_zero_idx = 2; phi_x_idx = true_path; break; 1575 default: return NULL; break; 1576 } 1577 } 1578 1579 // Test is next 1580 const Type *tzero = NULL; 1581 switch (cmp->Opcode()) { 1582 case Op_CmpI: tzero = TypeInt::ZERO; break; // Integer ABS 1583 case Op_CmpL: tzero = TypeLong::ZERO; break; // Long ABS 1584 case Op_CmpF: tzero = TypeF::ZERO; break; // Float ABS 1585 case Op_CmpD: tzero = TypeD::ZERO; break; // Double ABS 1586 default: return NULL; 1587 } 1588 1589 // Find zero input of compare; the other input is being abs'd 1590 Node *x = NULL; 1591 bool flip = false; 1592 if( phase->type(cmp->in(cmp_zero_idx)) == tzero ) { 1593 x = cmp->in(3 - cmp_zero_idx); 1594 } else if( phase->type(cmp->in(3 - cmp_zero_idx)) == tzero ) { 1595 // The test is inverted, we should invert the result... 1596 x = cmp->in(cmp_zero_idx); 1597 flip = true; 1598 } else { 1599 return NULL; 1600 } 1601 1602 // Next get the 2 pieces being selected, one is the original value 1603 // and the other is the negated value. 1604 if( phi_root->in(phi_x_idx) != x ) return NULL; 1605 1606 // Check other phi input for subtract node 1607 Node *sub = phi_root->in(3 - phi_x_idx); 1608 1609 bool is_sub = sub->Opcode() == Op_SubF || sub->Opcode() == Op_SubD || 1610 sub->Opcode() == Op_SubI || sub->Opcode() == Op_SubL; 1611 1612 // Allow only Sub(0,X) and fail out for all others; Neg is not OK 1613 if (!is_sub || phase->type(sub->in(1)) != tzero || sub->in(2) != x) return NULL; 1614 1615 if (tzero == TypeF::ZERO) { 1616 x = new AbsFNode(x); 1617 if (flip) { 1618 x = new SubFNode(sub->in(1), phase->transform(x)); 1619 } 1620 } else if (tzero == TypeD::ZERO) { 1621 x = new AbsDNode(x); 1622 if (flip) { 1623 x = new SubDNode(sub->in(1), phase->transform(x)); 1624 } 1625 } else if (tzero == TypeInt::ZERO && Matcher::match_rule_supported(Op_AbsI)) { 1626 x = new AbsINode(x); 1627 if (flip) { 1628 x = new SubINode(sub->in(1), phase->transform(x)); 1629 } 1630 } else if (tzero == TypeLong::ZERO && Matcher::match_rule_supported(Op_AbsL)) { 1631 x = new AbsLNode(x); 1632 if (flip) { 1633 x = new SubLNode(sub->in(1), phase->transform(x)); 1634 } 1635 } else return NULL; 1636 1637 return x; 1638 } 1639 1640 //------------------------------split_once------------------------------------- 1641 // Helper for split_flow_path 1642 static void split_once(PhaseIterGVN *igvn, Node *phi, Node *val, Node *n, Node *newn) { 1643 igvn->hash_delete(n); // Remove from hash before hacking edges 1644 1645 uint j = 1; 1646 for (uint i = phi->req()-1; i > 0; i--) { 1647 if (phi->in(i) == val) { // Found a path with val? 1648 // Add to NEW Region/Phi, no DU info 1649 newn->set_req( j++, n->in(i) ); 1650 // Remove from OLD Region/Phi 1651 n->del_req(i); 1652 } 1653 } 1654 1655 // Register the new node but do not transform it. Cannot transform until the 1656 // entire Region/Phi conglomerate has been hacked as a single huge transform. 1657 igvn->register_new_node_with_optimizer( newn ); 1658 1659 // Now I can point to the new node. 1660 n->add_req(newn); 1661 igvn->_worklist.push(n); 1662 } 1663 1664 //------------------------------split_flow_path-------------------------------- 1665 // Check for merging identical values and split flow paths 1666 static Node* split_flow_path(PhaseGVN *phase, PhiNode *phi) { 1667 BasicType bt = phi->type()->basic_type(); 1668 if( bt == T_ILLEGAL || type2size[bt] <= 0 ) 1669 return NULL; // Bail out on funny non-value stuff 1670 if( phi->req() <= 3 ) // Need at least 2 matched inputs and a 1671 return NULL; // third unequal input to be worth doing 1672 1673 // Scan for a constant 1674 uint i; 1675 for( i = 1; i < phi->req()-1; i++ ) { 1676 Node *n = phi->in(i); 1677 if( !n ) return NULL; 1678 if( phase->type(n) == Type::TOP ) return NULL; 1679 if( n->Opcode() == Op_ConP || n->Opcode() == Op_ConN || n->Opcode() == Op_ConNKlass ) 1680 break; 1681 } 1682 if( i >= phi->req() ) // Only split for constants 1683 return NULL; 1684 1685 Node *val = phi->in(i); // Constant to split for 1686 uint hit = 0; // Number of times it occurs 1687 Node *r = phi->region(); 1688 1689 for( ; i < phi->req(); i++ ){ // Count occurrences of constant 1690 Node *n = phi->in(i); 1691 if( !n ) return NULL; 1692 if( phase->type(n) == Type::TOP ) return NULL; 1693 if( phi->in(i) == val ) { 1694 hit++; 1695 if (PhaseIdealLoop::find_predicate(r->in(i)) != NULL) { 1696 return NULL; // don't split loop entry path 1697 } 1698 } 1699 } 1700 1701 if( hit <= 1 || // Make sure we find 2 or more 1702 hit == phi->req()-1 ) // and not ALL the same value 1703 return NULL; 1704 1705 // Now start splitting out the flow paths that merge the same value. 1706 // Split first the RegionNode. 1707 PhaseIterGVN *igvn = phase->is_IterGVN(); 1708 RegionNode *newr = new RegionNode(hit+1); 1709 split_once(igvn, phi, val, r, newr); 1710 1711 // Now split all other Phis than this one 1712 for (DUIterator_Fast kmax, k = r->fast_outs(kmax); k < kmax; k++) { 1713 Node* phi2 = r->fast_out(k); 1714 if( phi2->is_Phi() && phi2->as_Phi() != phi ) { 1715 PhiNode *newphi = PhiNode::make_blank(newr, phi2); 1716 split_once(igvn, phi, val, phi2, newphi); 1717 } 1718 } 1719 1720 // Clean up this guy 1721 igvn->hash_delete(phi); 1722 for( i = phi->req()-1; i > 0; i-- ) { 1723 if( phi->in(i) == val ) { 1724 phi->del_req(i); 1725 } 1726 } 1727 phi->add_req(val); 1728 1729 return phi; 1730 } 1731 1732 //============================================================================= 1733 //------------------------------simple_data_loop_check------------------------- 1734 // Try to determining if the phi node in a simple safe/unsafe data loop. 1735 // Returns: 1736 // enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop }; 1737 // Safe - safe case when the phi and it's inputs reference only safe data 1738 // nodes; 1739 // Unsafe - the phi and it's inputs reference unsafe data nodes but there 1740 // is no reference back to the phi - need a graph walk 1741 // to determine if it is in a loop; 1742 // UnsafeLoop - unsafe case when the phi references itself directly or through 1743 // unsafe data node. 1744 // Note: a safe data node is a node which could/never reference itself during 1745 // GVN transformations. For now it is Con, Proj, Phi, CastPP, CheckCastPP. 1746 // I mark Phi nodes as safe node not only because they can reference itself 1747 // but also to prevent mistaking the fallthrough case inside an outer loop 1748 // as dead loop when the phi references itselfs through an other phi. 1749 PhiNode::LoopSafety PhiNode::simple_data_loop_check(Node *in) const { 1750 // It is unsafe loop if the phi node references itself directly. 1751 if (in == (Node*)this) 1752 return UnsafeLoop; // Unsafe loop 1753 // Unsafe loop if the phi node references itself through an unsafe data node. 1754 // Exclude cases with null inputs or data nodes which could reference 1755 // itself (safe for dead loops). 1756 if (in != NULL && !in->is_dead_loop_safe()) { 1757 // Check inputs of phi's inputs also. 1758 // It is much less expensive then full graph walk. 1759 uint cnt = in->req(); 1760 uint i = (in->is_Proj() && !in->is_CFG()) ? 0 : 1; 1761 for (; i < cnt; ++i) { 1762 Node* m = in->in(i); 1763 if (m == (Node*)this) 1764 return UnsafeLoop; // Unsafe loop 1765 if (m != NULL && !m->is_dead_loop_safe()) { 1766 // Check the most common case (about 30% of all cases): 1767 // phi->Load/Store->AddP->(ConP ConP Con)/(Parm Parm Con). 1768 Node *m1 = (m->is_AddP() && m->req() > 3) ? m->in(1) : NULL; 1769 if (m1 == (Node*)this) 1770 return UnsafeLoop; // Unsafe loop 1771 if (m1 != NULL && m1 == m->in(2) && 1772 m1->is_dead_loop_safe() && m->in(3)->is_Con()) { 1773 continue; // Safe case 1774 } 1775 // The phi references an unsafe node - need full analysis. 1776 return Unsafe; 1777 } 1778 } 1779 } 1780 return Safe; // Safe case - we can optimize the phi node. 1781 } 1782 1783 //------------------------------is_unsafe_data_reference----------------------- 1784 // If phi can be reached through the data input - it is data loop. 1785 bool PhiNode::is_unsafe_data_reference(Node *in) const { 1786 assert(req() > 1, ""); 1787 // First, check simple cases when phi references itself directly or 1788 // through an other node. 1789 LoopSafety safety = simple_data_loop_check(in); 1790 if (safety == UnsafeLoop) 1791 return true; // phi references itself - unsafe loop 1792 else if (safety == Safe) 1793 return false; // Safe case - phi could be replaced with the unique input. 1794 1795 // Unsafe case when we should go through data graph to determine 1796 // if the phi references itself. 1797 1798 ResourceMark rm; 1799 1800 Node_List nstack; 1801 VectorSet visited; 1802 1803 nstack.push(in); // Start with unique input. 1804 visited.set(in->_idx); 1805 while (nstack.size() != 0) { 1806 Node* n = nstack.pop(); 1807 uint cnt = n->req(); 1808 uint i = (n->is_Proj() && !n->is_CFG()) ? 0 : 1; 1809 for (; i < cnt; i++) { 1810 Node* m = n->in(i); 1811 if (m == (Node*)this) { 1812 return true; // Data loop 1813 } 1814 if (m != NULL && !m->is_dead_loop_safe()) { // Only look for unsafe cases. 1815 if (!visited.test_set(m->_idx)) 1816 nstack.push(m); 1817 } 1818 } 1819 } 1820 return false; // The phi is not reachable from its inputs 1821 } 1822 1823 // Is this Phi's region or some inputs to the region enqueued for IGVN 1824 // and so could cause the region to be optimized out? 1825 bool PhiNode::wait_for_region_igvn(PhaseGVN* phase) { 1826 PhaseIterGVN* igvn = phase->is_IterGVN(); 1827 Unique_Node_List& worklist = igvn->_worklist; 1828 bool delay = false; 1829 Node* r = in(0); 1830 for (uint j = 1; j < req(); j++) { 1831 Node* rc = r->in(j); 1832 Node* n = in(j); 1833 if (rc != NULL && 1834 rc->is_Proj()) { 1835 if (worklist.member(rc)) { 1836 delay = true; 1837 } else if (rc->in(0) != NULL && 1838 rc->in(0)->is_If()) { 1839 if (worklist.member(rc->in(0))) { 1840 delay = true; 1841 } else if (rc->in(0)->in(1) != NULL && 1842 rc->in(0)->in(1)->is_Bool()) { 1843 if (worklist.member(rc->in(0)->in(1))) { 1844 delay = true; 1845 } else if (rc->in(0)->in(1)->in(1) != NULL && 1846 rc->in(0)->in(1)->in(1)->is_Cmp()) { 1847 if (worklist.member(rc->in(0)->in(1)->in(1))) { 1848 delay = true; 1849 } 1850 } 1851 } 1852 } 1853 } 1854 } 1855 if (delay) { 1856 worklist.push(this); 1857 } 1858 return delay; 1859 } 1860 1861 //------------------------------Ideal------------------------------------------ 1862 // Return a node which is more "ideal" than the current node. Must preserve 1863 // the CFG, but we can still strip out dead paths. 1864 Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1865 // The next should never happen after 6297035 fix. 1866 if( is_copy() ) // Already degraded to a Copy ? 1867 return NULL; // No change 1868 1869 Node *r = in(0); // RegionNode 1870 assert(r->in(0) == NULL || !r->in(0)->is_Root(), "not a specially hidden merge"); 1871 1872 // Note: During parsing, phis are often transformed before their regions. 1873 // This means we have to use type_or_null to defend against untyped regions. 1874 if( phase->type_or_null(r) == Type::TOP ) // Dead code? 1875 return NULL; // No change 1876 1877 Node *top = phase->C->top(); 1878 bool new_phi = (outcnt() == 0); // transforming new Phi 1879 // No change for igvn if new phi is not hooked 1880 if (new_phi && can_reshape) 1881 return NULL; 1882 1883 // The are 2 situations when only one valid phi's input is left 1884 // (in addition to Region input). 1885 // One: region is not loop - replace phi with this input. 1886 // Two: region is loop - replace phi with top since this data path is dead 1887 // and we need to break the dead data loop. 1888 Node* progress = NULL; // Record if any progress made 1889 for( uint j = 1; j < req(); ++j ){ // For all paths in 1890 // Check unreachable control paths 1891 Node* rc = r->in(j); 1892 Node* n = in(j); // Get the input 1893 if (rc == NULL || phase->type(rc) == Type::TOP) { 1894 if (n != top) { // Not already top? 1895 PhaseIterGVN *igvn = phase->is_IterGVN(); 1896 if (can_reshape && igvn != NULL) { 1897 igvn->_worklist.push(r); 1898 } 1899 // Nuke it down 1900 if (can_reshape) { 1901 set_req_X(j, top, igvn); 1902 } else { 1903 set_req(j, top); 1904 } 1905 progress = this; // Record progress 1906 } 1907 } 1908 } 1909 1910 if (can_reshape && outcnt() == 0) { 1911 // set_req() above may kill outputs if Phi is referenced 1912 // only by itself on the dead (top) control path. 1913 return top; 1914 } 1915 1916 bool uncasted = false; 1917 Node* uin = unique_input(phase, false); 1918 if (uin == NULL && can_reshape && 1919 // If there is a chance that the region can be optimized out do 1920 // not add a cast node that we can't remove yet. 1921 !wait_for_region_igvn(phase)) { 1922 uncasted = true; 1923 uin = unique_input(phase, true); 1924 } 1925 if (uin == top) { // Simplest case: no alive inputs. 1926 if (can_reshape) // IGVN transformation 1927 return top; 1928 else 1929 return NULL; // Identity will return TOP 1930 } else if (uin != NULL) { 1931 // Only one not-NULL unique input path is left. 1932 // Determine if this input is backedge of a loop. 1933 // (Skip new phis which have no uses and dead regions). 1934 if (outcnt() > 0 && r->in(0) != NULL) { 1935 // First, take the short cut when we know it is a loop and 1936 // the EntryControl data path is dead. 1937 // Loop node may have only one input because entry path 1938 // is removed in PhaseIdealLoop::Dominators(). 1939 assert(!r->is_Loop() || r->req() <= 3, "Loop node should have 3 or less inputs"); 1940 bool is_loop = (r->is_Loop() && r->req() == 3); 1941 // Then, check if there is a data loop when phi references itself directly 1942 // or through other data nodes. 1943 if ((is_loop && !uin->eqv_uncast(in(LoopNode::EntryControl))) || 1944 (!is_loop && is_unsafe_data_reference(uin))) { 1945 // Break this data loop to avoid creation of a dead loop. 1946 if (can_reshape) { 1947 return top; 1948 } else { 1949 // We can't return top if we are in Parse phase - cut inputs only 1950 // let Identity to handle the case. 1951 replace_edge(uin, top); 1952 return NULL; 1953 } 1954 } 1955 } 1956 1957 if (uncasted) { 1958 // Add cast nodes between the phi to be removed and its unique input. 1959 // Wait until after parsing for the type information to propagate from the casts. 1960 assert(can_reshape, "Invalid during parsing"); 1961 const Type* phi_type = bottom_type(); 1962 assert(phi_type->isa_int() || phi_type->isa_ptr(), "bad phi type"); 1963 // Add casts to carry the control dependency of the Phi that is 1964 // going away 1965 Node* cast = NULL; 1966 if (phi_type->isa_int()) { 1967 cast = ConstraintCastNode::make_cast(Op_CastII, r, uin, phi_type, true); 1968 } else { 1969 const Type* uin_type = phase->type(uin); 1970 if (!phi_type->isa_oopptr() && !uin_type->isa_oopptr()) { 1971 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, phi_type, true); 1972 } else { 1973 // Use a CastPP for a cast to not null and a CheckCastPP for 1974 // a cast to a new klass (and both if both null-ness and 1975 // klass change). 1976 1977 // If the type of phi is not null but the type of uin may be 1978 // null, uin's type must be casted to not null 1979 if (phi_type->join(TypePtr::NOTNULL) == phi_type->remove_speculative() && 1980 uin_type->join(TypePtr::NOTNULL) != uin_type->remove_speculative()) { 1981 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, TypePtr::NOTNULL, true); 1982 } 1983 1984 // If the type of phi and uin, both casted to not null, 1985 // differ the klass of uin must be (check)cast'ed to match 1986 // that of phi 1987 if (phi_type->join_speculative(TypePtr::NOTNULL) != uin_type->join_speculative(TypePtr::NOTNULL)) { 1988 Node* n = uin; 1989 if (cast != NULL) { 1990 cast = phase->transform(cast); 1991 n = cast; 1992 } 1993 cast = ConstraintCastNode::make_cast(Op_CheckCastPP, r, n, phi_type, true); 1994 } 1995 if (cast == NULL) { 1996 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, phi_type, true); 1997 } 1998 } 1999 } 2000 assert(cast != NULL, "cast should be set"); 2001 cast = phase->transform(cast); 2002 // set all inputs to the new cast(s) so the Phi is removed by Identity 2003 PhaseIterGVN* igvn = phase->is_IterGVN(); 2004 for (uint i = 1; i < req(); i++) { 2005 set_req_X(i, cast, igvn); 2006 } 2007 uin = cast; 2008 } 2009 2010 // One unique input. 2011 debug_only(Node* ident = Identity(phase)); 2012 // The unique input must eventually be detected by the Identity call. 2013 #ifdef ASSERT 2014 if (ident != uin && !ident->is_top()) { 2015 // print this output before failing assert 2016 r->dump(3); 2017 this->dump(3); 2018 ident->dump(); 2019 uin->dump(); 2020 } 2021 #endif 2022 assert(ident == uin || ident->is_top(), "Identity must clean this up"); 2023 return NULL; 2024 } 2025 2026 Node* opt = NULL; 2027 int true_path = is_diamond_phi(); 2028 if( true_path != 0 ) { 2029 // Check for CMove'ing identity. If it would be unsafe, 2030 // handle it here. In the safe case, let Identity handle it. 2031 Node* unsafe_id = is_cmove_id(phase, true_path); 2032 if( unsafe_id != NULL && is_unsafe_data_reference(unsafe_id) ) 2033 opt = unsafe_id; 2034 2035 // Check for simple convert-to-boolean pattern 2036 if( opt == NULL ) 2037 opt = is_x2logic(phase, this, true_path); 2038 2039 // Check for absolute value 2040 if( opt == NULL ) 2041 opt = is_absolute(phase, this, true_path); 2042 2043 // Check for conditional add 2044 if( opt == NULL && can_reshape ) 2045 opt = is_cond_add(phase, this, true_path); 2046 2047 // These 4 optimizations could subsume the phi: 2048 // have to check for a dead data loop creation. 2049 if( opt != NULL ) { 2050 if( opt == unsafe_id || is_unsafe_data_reference(opt) ) { 2051 // Found dead loop. 2052 if( can_reshape ) 2053 return top; 2054 // We can't return top if we are in Parse phase - cut inputs only 2055 // to stop further optimizations for this phi. Identity will return TOP. 2056 assert(req() == 3, "only diamond merge phi here"); 2057 set_req(1, top); 2058 set_req(2, top); 2059 return NULL; 2060 } else { 2061 return opt; 2062 } 2063 } 2064 } 2065 2066 // Check for merging identical values and split flow paths 2067 if (can_reshape) { 2068 opt = split_flow_path(phase, this); 2069 // This optimization only modifies phi - don't need to check for dead loop. 2070 assert(opt == NULL || phase->eqv(opt, this), "do not elide phi"); 2071 if (opt != NULL) return opt; 2072 } 2073 2074 if (in(1) != NULL && in(1)->Opcode() == Op_AddP && can_reshape) { 2075 // Try to undo Phi of AddP: 2076 // (Phi (AddP base address offset) (AddP base2 address2 offset2)) 2077 // becomes: 2078 // newbase := (Phi base base2) 2079 // newaddress := (Phi address address2) 2080 // newoffset := (Phi offset offset2) 2081 // (AddP newbase newaddress newoffset) 2082 // 2083 // This occurs as a result of unsuccessful split_thru_phi and 2084 // interferes with taking advantage of addressing modes. See the 2085 // clone_shift_expressions code in matcher.cpp 2086 Node* addp = in(1); 2087 Node* base = addp->in(AddPNode::Base); 2088 Node* address = addp->in(AddPNode::Address); 2089 Node* offset = addp->in(AddPNode::Offset); 2090 if (base != NULL && address != NULL && offset != NULL && 2091 !base->is_top() && !address->is_top() && !offset->is_top()) { 2092 const Type* base_type = base->bottom_type(); 2093 const Type* address_type = address->bottom_type(); 2094 // make sure that all the inputs are similar to the first one, 2095 // i.e. AddP with base == address and same offset as first AddP 2096 bool doit = true; 2097 for (uint i = 2; i < req(); i++) { 2098 if (in(i) == NULL || 2099 in(i)->Opcode() != Op_AddP || 2100 in(i)->in(AddPNode::Base) == NULL || 2101 in(i)->in(AddPNode::Address) == NULL || 2102 in(i)->in(AddPNode::Offset) == NULL || 2103 in(i)->in(AddPNode::Base)->is_top() || 2104 in(i)->in(AddPNode::Address)->is_top() || 2105 in(i)->in(AddPNode::Offset)->is_top()) { 2106 doit = false; 2107 break; 2108 } 2109 if (in(i)->in(AddPNode::Offset) != base) { 2110 base = NULL; 2111 } 2112 if (in(i)->in(AddPNode::Offset) != offset) { 2113 offset = NULL; 2114 } 2115 if (in(i)->in(AddPNode::Address) != address) { 2116 address = NULL; 2117 } 2118 // Accumulate type for resulting Phi 2119 base_type = base_type->meet_speculative(in(i)->in(AddPNode::Base)->bottom_type()); 2120 address_type = address_type->meet_speculative(in(i)->in(AddPNode::Address)->bottom_type()); 2121 } 2122 if (doit && base == NULL) { 2123 // Check for neighboring AddP nodes in a tree. 2124 // If they have a base, use that it. 2125 for (DUIterator_Fast kmax, k = this->fast_outs(kmax); k < kmax; k++) { 2126 Node* u = this->fast_out(k); 2127 if (u->is_AddP()) { 2128 Node* base2 = u->in(AddPNode::Base); 2129 if (base2 != NULL && !base2->is_top()) { 2130 if (base == NULL) 2131 base = base2; 2132 else if (base != base2) 2133 { doit = false; break; } 2134 } 2135 } 2136 } 2137 } 2138 if (doit) { 2139 if (base == NULL) { 2140 base = new PhiNode(in(0), base_type, NULL); 2141 for (uint i = 1; i < req(); i++) { 2142 base->init_req(i, in(i)->in(AddPNode::Base)); 2143 } 2144 phase->is_IterGVN()->register_new_node_with_optimizer(base); 2145 } 2146 if (address == NULL) { 2147 address = new PhiNode(in(0), address_type, NULL); 2148 for (uint i = 1; i < req(); i++) { 2149 address->init_req(i, in(i)->in(AddPNode::Address)); 2150 } 2151 phase->is_IterGVN()->register_new_node_with_optimizer(address); 2152 } 2153 if (offset == NULL) { 2154 offset = new PhiNode(in(0), TypeX_X, NULL); 2155 for (uint i = 1; i < req(); i++) { 2156 offset->init_req(i, in(i)->in(AddPNode::Offset)); 2157 } 2158 phase->is_IterGVN()->register_new_node_with_optimizer(offset); 2159 } 2160 return new AddPNode(base, address, offset); 2161 } 2162 } 2163 } 2164 2165 // Split phis through memory merges, so that the memory merges will go away. 2166 // Piggy-back this transformation on the search for a unique input.... 2167 // It will be as if the merged memory is the unique value of the phi. 2168 // (Do not attempt this optimization unless parsing is complete. 2169 // It would make the parser's memory-merge logic sick.) 2170 // (MergeMemNode is not dead_loop_safe - need to check for dead loop.) 2171 if (progress == NULL && can_reshape && type() == Type::MEMORY) { 2172 // see if this phi should be sliced 2173 uint merge_width = 0; 2174 bool saw_self = false; 2175 for( uint i=1; i<req(); ++i ) {// For all paths in 2176 Node *ii = in(i); 2177 // TOP inputs should not be counted as safe inputs because if the 2178 // Phi references itself through all other inputs then splitting the 2179 // Phi through memory merges would create dead loop at later stage. 2180 if (ii == top) { 2181 return NULL; // Delay optimization until graph is cleaned. 2182 } 2183 if (ii->is_MergeMem()) { 2184 MergeMemNode* n = ii->as_MergeMem(); 2185 merge_width = MAX2(merge_width, n->req()); 2186 saw_self = saw_self || phase->eqv(n->base_memory(), this); 2187 } 2188 } 2189 2190 // This restriction is temporarily necessary to ensure termination: 2191 if (!saw_self && adr_type() == TypePtr::BOTTOM) merge_width = 0; 2192 2193 if (merge_width > Compile::AliasIdxRaw) { 2194 // found at least one non-empty MergeMem 2195 const TypePtr* at = adr_type(); 2196 if (at != TypePtr::BOTTOM) { 2197 // Patch the existing phi to select an input from the merge: 2198 // Phi:AT1(...MergeMem(m0, m1, m2)...) into 2199 // Phi:AT1(...m1...) 2200 int alias_idx = phase->C->get_alias_index(at); 2201 for (uint i=1; i<req(); ++i) { 2202 Node *ii = in(i); 2203 if (ii->is_MergeMem()) { 2204 MergeMemNode* n = ii->as_MergeMem(); 2205 // compress paths and change unreachable cycles to TOP 2206 // If not, we can update the input infinitely along a MergeMem cycle 2207 // Equivalent code is in MemNode::Ideal_common 2208 Node *m = phase->transform(n); 2209 if (outcnt() == 0) { // Above transform() may kill us! 2210 return top; 2211 } 2212 // If transformed to a MergeMem, get the desired slice 2213 // Otherwise the returned node represents memory for every slice 2214 Node *new_mem = (m->is_MergeMem()) ? 2215 m->as_MergeMem()->memory_at(alias_idx) : m; 2216 // Update input if it is progress over what we have now 2217 if (new_mem != ii) { 2218 set_req(i, new_mem); 2219 progress = this; 2220 } 2221 } 2222 } 2223 } else { 2224 // We know that at least one MergeMem->base_memory() == this 2225 // (saw_self == true). If all other inputs also references this phi 2226 // (directly or through data nodes) - it is a dead loop. 2227 bool saw_safe_input = false; 2228 for (uint j = 1; j < req(); ++j) { 2229 Node* n = in(j); 2230 if (n->is_MergeMem()) { 2231 MergeMemNode* mm = n->as_MergeMem(); 2232 if (mm->base_memory() == this || mm->base_memory() == mm->empty_memory()) { 2233 // Skip this input if it references back to this phi or if the memory path is dead 2234 continue; 2235 } 2236 } 2237 if (!is_unsafe_data_reference(n)) { 2238 saw_safe_input = true; // found safe input 2239 break; 2240 } 2241 } 2242 if (!saw_safe_input) { 2243 // There is a dead loop: All inputs are either dead or reference back to this phi 2244 return top; 2245 } 2246 2247 // Phi(...MergeMem(m0, m1:AT1, m2:AT2)...) into 2248 // MergeMem(Phi(...m0...), Phi:AT1(...m1...), Phi:AT2(...m2...)) 2249 PhaseIterGVN* igvn = phase->is_IterGVN(); 2250 Node* hook = new Node(1); 2251 PhiNode* new_base = (PhiNode*) clone(); 2252 // Must eagerly register phis, since they participate in loops. 2253 if (igvn) { 2254 igvn->register_new_node_with_optimizer(new_base); 2255 hook->add_req(new_base); 2256 } 2257 MergeMemNode* result = MergeMemNode::make(new_base); 2258 for (uint i = 1; i < req(); ++i) { 2259 Node *ii = in(i); 2260 if (ii->is_MergeMem()) { 2261 MergeMemNode* n = ii->as_MergeMem(); 2262 for (MergeMemStream mms(result, n); mms.next_non_empty2(); ) { 2263 // If we have not seen this slice yet, make a phi for it. 2264 bool made_new_phi = false; 2265 if (mms.is_empty()) { 2266 Node* new_phi = new_base->slice_memory(mms.adr_type(phase->C)); 2267 made_new_phi = true; 2268 if (igvn) { 2269 igvn->register_new_node_with_optimizer(new_phi); 2270 hook->add_req(new_phi); 2271 } 2272 mms.set_memory(new_phi); 2273 } 2274 Node* phi = mms.memory(); 2275 assert(made_new_phi || phi->in(i) == n, "replace the i-th merge by a slice"); 2276 phi->set_req(i, mms.memory2()); 2277 } 2278 } 2279 } 2280 // Distribute all self-loops. 2281 { // (Extra braces to hide mms.) 2282 for (MergeMemStream mms(result); mms.next_non_empty(); ) { 2283 Node* phi = mms.memory(); 2284 for (uint i = 1; i < req(); ++i) { 2285 if (phi->in(i) == this) phi->set_req(i, phi); 2286 } 2287 } 2288 } 2289 // now transform the new nodes, and return the mergemem 2290 for (MergeMemStream mms(result); mms.next_non_empty(); ) { 2291 Node* phi = mms.memory(); 2292 mms.set_memory(phase->transform(phi)); 2293 } 2294 if (igvn) { // Unhook. 2295 igvn->hash_delete(hook); 2296 for (uint i = 1; i < hook->req(); i++) { 2297 hook->set_req(i, NULL); 2298 } 2299 } 2300 // Replace self with the result. 2301 return result; 2302 } 2303 } 2304 // 2305 // Other optimizations on the memory chain 2306 // 2307 const TypePtr* at = adr_type(); 2308 for( uint i=1; i<req(); ++i ) {// For all paths in 2309 Node *ii = in(i); 2310 Node *new_in = MemNode::optimize_memory_chain(ii, at, NULL, phase); 2311 if (ii != new_in ) { 2312 set_req(i, new_in); 2313 progress = this; 2314 } 2315 } 2316 } 2317 2318 #ifdef _LP64 2319 // Push DecodeN/DecodeNKlass down through phi. 2320 // The rest of phi graph will transform by split EncodeP node though phis up. 2321 if ((UseCompressedOops || UseCompressedClassPointers) && can_reshape && progress == NULL) { 2322 bool may_push = true; 2323 bool has_decodeN = false; 2324 bool is_decodeN = false; 2325 for (uint i=1; i<req(); ++i) {// For all paths in 2326 Node *ii = in(i); 2327 if (ii->is_DecodeNarrowPtr() && ii->bottom_type() == bottom_type()) { 2328 // Do optimization if a non dead path exist. 2329 if (ii->in(1)->bottom_type() != Type::TOP) { 2330 has_decodeN = true; 2331 is_decodeN = ii->is_DecodeN(); 2332 } 2333 } else if (!ii->is_Phi()) { 2334 may_push = false; 2335 } 2336 } 2337 2338 if (has_decodeN && may_push) { 2339 PhaseIterGVN *igvn = phase->is_IterGVN(); 2340 // Make narrow type for new phi. 2341 const Type* narrow_t; 2342 if (is_decodeN) { 2343 narrow_t = TypeNarrowOop::make(this->bottom_type()->is_ptr()); 2344 } else { 2345 narrow_t = TypeNarrowKlass::make(this->bottom_type()->is_ptr()); 2346 } 2347 PhiNode* new_phi = new PhiNode(r, narrow_t); 2348 uint orig_cnt = req(); 2349 for (uint i=1; i<req(); ++i) {// For all paths in 2350 Node *ii = in(i); 2351 Node* new_ii = NULL; 2352 if (ii->is_DecodeNarrowPtr()) { 2353 assert(ii->bottom_type() == bottom_type(), "sanity"); 2354 new_ii = ii->in(1); 2355 } else { 2356 assert(ii->is_Phi(), "sanity"); 2357 if (ii->as_Phi() == this) { 2358 new_ii = new_phi; 2359 } else { 2360 if (is_decodeN) { 2361 new_ii = new EncodePNode(ii, narrow_t); 2362 } else { 2363 new_ii = new EncodePKlassNode(ii, narrow_t); 2364 } 2365 igvn->register_new_node_with_optimizer(new_ii); 2366 } 2367 } 2368 new_phi->set_req(i, new_ii); 2369 } 2370 igvn->register_new_node_with_optimizer(new_phi, this); 2371 if (is_decodeN) { 2372 progress = new DecodeNNode(new_phi, bottom_type()); 2373 } else { 2374 progress = new DecodeNKlassNode(new_phi, bottom_type()); 2375 } 2376 } 2377 } 2378 #endif 2379 2380 // Phi (VB ... VB) => VB (Phi ...) (Phi ...) 2381 if (EnableVectorReboxing && can_reshape && progress == NULL) { 2382 PhaseIterGVN *igvn = phase->is_IterGVN(); 2383 2384 bool all_inputs_are_equiv_vboxes = true; 2385 for (uint i = 1; i < req(); ++i) { 2386 Node *n = in(i); 2387 if (in(i)->Opcode() != Op_VectorBox) { 2388 all_inputs_are_equiv_vboxes = false; 2389 break; 2390 } 2391 // Check that vector type of vboxes is equivalent 2392 if (i != 1) { 2393 if (Type::cmp(in(i-0)->in(VectorBoxNode::Value)->bottom_type(), 2394 in(i-1)->in(VectorBoxNode::Value)->bottom_type()) != 0) { 2395 all_inputs_are_equiv_vboxes = false; 2396 break; 2397 } 2398 if (Type::cmp(in(i-0)->in(VectorBoxNode::Box)->bottom_type(), 2399 in(i-1)->in(VectorBoxNode::Box)->bottom_type()) != 0) { 2400 all_inputs_are_equiv_vboxes = false; 2401 break; 2402 } 2403 } 2404 } 2405 2406 if (all_inputs_are_equiv_vboxes) { 2407 VectorBoxNode* vbox = static_cast<VectorBoxNode*>(in(1)); 2408 PhiNode* new_vbox_phi = new PhiNode(r, vbox->box_type()); 2409 PhiNode* new_vect_phi = new PhiNode(r, vbox->vec_type()); 2410 for (uint i = 1; i < req(); ++i) { 2411 VectorBoxNode* old_vbox = static_cast<VectorBoxNode*>(in(i)); 2412 new_vbox_phi->set_req(i, old_vbox->in(VectorBoxNode::Box)); 2413 new_vect_phi->set_req(i, old_vbox->in(VectorBoxNode::Value)); 2414 } 2415 igvn->register_new_node_with_optimizer(new_vbox_phi, this); 2416 igvn->register_new_node_with_optimizer(new_vect_phi, this); 2417 progress = new VectorBoxNode(igvn->C, new_vbox_phi, new_vect_phi, vbox->box_type(), vbox->vec_type()); 2418 } 2419 } 2420 2421 return progress; // Return any progress 2422 } 2423 2424 //------------------------------is_tripcount----------------------------------- 2425 bool PhiNode::is_tripcount() const { 2426 return (in(0) != NULL && in(0)->is_CountedLoop() && 2427 in(0)->as_CountedLoop()->phi() == this); 2428 } 2429 2430 //------------------------------out_RegMask------------------------------------ 2431 const RegMask &PhiNode::in_RegMask(uint i) const { 2432 return i ? out_RegMask() : RegMask::Empty; 2433 } 2434 2435 const RegMask &PhiNode::out_RegMask() const { 2436 uint ideal_reg = _type->ideal_reg(); 2437 assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" ); 2438 if( ideal_reg == 0 ) return RegMask::Empty; 2439 assert(ideal_reg != Op_RegFlags, "flags register is not spillable"); 2440 return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]); 2441 } 2442 2443 #ifndef PRODUCT 2444 void PhiNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { 2445 // For a PhiNode, the set of related nodes includes all inputs till level 2, 2446 // and all outputs till level 1. In compact mode, inputs till level 1 are 2447 // collected. 2448 this->collect_nodes(in_rel, compact ? 1 : 2, false, false); 2449 this->collect_nodes(out_rel, -1, false, false); 2450 } 2451 2452 void PhiNode::dump_spec(outputStream *st) const { 2453 TypeNode::dump_spec(st); 2454 if (is_tripcount()) { 2455 st->print(" #tripcount"); 2456 } 2457 } 2458 #endif 2459 2460 2461 //============================================================================= 2462 const Type* GotoNode::Value(PhaseGVN* phase) const { 2463 // If the input is reachable, then we are executed. 2464 // If the input is not reachable, then we are not executed. 2465 return phase->type(in(0)); 2466 } 2467 2468 Node* GotoNode::Identity(PhaseGVN* phase) { 2469 return in(0); // Simple copy of incoming control 2470 } 2471 2472 const RegMask &GotoNode::out_RegMask() const { 2473 return RegMask::Empty; 2474 } 2475 2476 #ifndef PRODUCT 2477 //-----------------------------related----------------------------------------- 2478 // The related nodes of a GotoNode are all inputs at level 1, as well as the 2479 // outputs at level 1. This is regardless of compact mode. 2480 void GotoNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { 2481 this->collect_nodes(in_rel, 1, false, false); 2482 this->collect_nodes(out_rel, -1, false, false); 2483 } 2484 #endif 2485 2486 2487 //============================================================================= 2488 const RegMask &JumpNode::out_RegMask() const { 2489 return RegMask::Empty; 2490 } 2491 2492 #ifndef PRODUCT 2493 //-----------------------------related----------------------------------------- 2494 // The related nodes of a JumpNode are all inputs at level 1, as well as the 2495 // outputs at level 2 (to include actual jump targets beyond projection nodes). 2496 // This is regardless of compact mode. 2497 void JumpNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { 2498 this->collect_nodes(in_rel, 1, false, false); 2499 this->collect_nodes(out_rel, -2, false, false); 2500 } 2501 #endif 2502 2503 //============================================================================= 2504 const RegMask &JProjNode::out_RegMask() const { 2505 return RegMask::Empty; 2506 } 2507 2508 //============================================================================= 2509 const RegMask &CProjNode::out_RegMask() const { 2510 return RegMask::Empty; 2511 } 2512 2513 2514 2515 //============================================================================= 2516 2517 uint PCTableNode::hash() const { return Node::hash() + _size; } 2518 bool PCTableNode::cmp( const Node &n ) const 2519 { return _size == ((PCTableNode&)n)._size; } 2520 2521 const Type *PCTableNode::bottom_type() const { 2522 const Type** f = TypeTuple::fields(_size); 2523 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; 2524 return TypeTuple::make(_size, f); 2525 } 2526 2527 //------------------------------Value------------------------------------------ 2528 // Compute the type of the PCTableNode. If reachable it is a tuple of 2529 // Control, otherwise the table targets are not reachable 2530 const Type* PCTableNode::Value(PhaseGVN* phase) const { 2531 if( phase->type(in(0)) == Type::CONTROL ) 2532 return bottom_type(); 2533 return Type::TOP; // All paths dead? Then so are we 2534 } 2535 2536 //------------------------------Ideal------------------------------------------ 2537 // Return a node which is more "ideal" than the current node. Strip out 2538 // control copies 2539 Node *PCTableNode::Ideal(PhaseGVN *phase, bool can_reshape) { 2540 return remove_dead_region(phase, can_reshape) ? this : NULL; 2541 } 2542 2543 //============================================================================= 2544 uint JumpProjNode::hash() const { 2545 return Node::hash() + _dest_bci; 2546 } 2547 2548 bool JumpProjNode::cmp( const Node &n ) const { 2549 return ProjNode::cmp(n) && 2550 _dest_bci == ((JumpProjNode&)n)._dest_bci; 2551 } 2552 2553 #ifndef PRODUCT 2554 void JumpProjNode::dump_spec(outputStream *st) const { 2555 ProjNode::dump_spec(st); 2556 st->print("@bci %d ",_dest_bci); 2557 } 2558 2559 void JumpProjNode::dump_compact_spec(outputStream *st) const { 2560 ProjNode::dump_compact_spec(st); 2561 st->print("(%d)%d@%d", _switch_val, _proj_no, _dest_bci); 2562 } 2563 2564 void JumpProjNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { 2565 // The related nodes of a JumpProjNode are its inputs and outputs at level 1. 2566 this->collect_nodes(in_rel, 1, false, false); 2567 this->collect_nodes(out_rel, -1, false, false); 2568 } 2569 #endif 2570 2571 //============================================================================= 2572 //------------------------------Value------------------------------------------ 2573 // Check for being unreachable, or for coming from a Rethrow. Rethrow's cannot 2574 // have the default "fall_through_index" path. 2575 const Type* CatchNode::Value(PhaseGVN* phase) const { 2576 // Unreachable? Then so are all paths from here. 2577 if( phase->type(in(0)) == Type::TOP ) return Type::TOP; 2578 // First assume all paths are reachable 2579 const Type** f = TypeTuple::fields(_size); 2580 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; 2581 // Identify cases that will always throw an exception 2582 // () rethrow call 2583 // () virtual or interface call with NULL receiver 2584 // () call is a check cast with incompatible arguments 2585 if( in(1)->is_Proj() ) { 2586 Node *i10 = in(1)->in(0); 2587 if( i10->is_Call() ) { 2588 CallNode *call = i10->as_Call(); 2589 // Rethrows always throw exceptions, never return 2590 if (call->entry_point() == OptoRuntime::rethrow_stub()) { 2591 f[CatchProjNode::fall_through_index] = Type::TOP; 2592 } else if( call->req() > TypeFunc::Parms ) { 2593 const Type *arg0 = phase->type( call->in(TypeFunc::Parms) ); 2594 // Check for null receiver to virtual or interface calls 2595 if( call->is_CallDynamicJava() && 2596 arg0->higher_equal(TypePtr::NULL_PTR) ) { 2597 f[CatchProjNode::fall_through_index] = Type::TOP; 2598 } 2599 } // End of if not a runtime stub 2600 } // End of if have call above me 2601 } // End of slot 1 is not a projection 2602 return TypeTuple::make(_size, f); 2603 } 2604 2605 //============================================================================= 2606 uint CatchProjNode::hash() const { 2607 return Node::hash() + _handler_bci; 2608 } 2609 2610 2611 bool CatchProjNode::cmp( const Node &n ) const { 2612 return ProjNode::cmp(n) && 2613 _handler_bci == ((CatchProjNode&)n)._handler_bci; 2614 } 2615 2616 2617 //------------------------------Identity--------------------------------------- 2618 // If only 1 target is possible, choose it if it is the main control 2619 Node* CatchProjNode::Identity(PhaseGVN* phase) { 2620 // If my value is control and no other value is, then treat as ID 2621 const TypeTuple *t = phase->type(in(0))->is_tuple(); 2622 if (t->field_at(_con) != Type::CONTROL) return this; 2623 // If we remove the last CatchProj and elide the Catch/CatchProj, then we 2624 // also remove any exception table entry. Thus we must know the call 2625 // feeding the Catch will not really throw an exception. This is ok for 2626 // the main fall-thru control (happens when we know a call can never throw 2627 // an exception) or for "rethrow", because a further optimization will 2628 // yank the rethrow (happens when we inline a function that can throw an 2629 // exception and the caller has no handler). Not legal, e.g., for passing 2630 // a NULL receiver to a v-call, or passing bad types to a slow-check-cast. 2631 // These cases MUST throw an exception via the runtime system, so the VM 2632 // will be looking for a table entry. 2633 Node *proj = in(0)->in(1); // Expect a proj feeding CatchNode 2634 CallNode *call; 2635 if (_con != TypeFunc::Control && // Bail out if not the main control. 2636 !(proj->is_Proj() && // AND NOT a rethrow 2637 proj->in(0)->is_Call() && 2638 (call = proj->in(0)->as_Call()) && 2639 call->entry_point() == OptoRuntime::rethrow_stub())) 2640 return this; 2641 2642 // Search for any other path being control 2643 for (uint i = 0; i < t->cnt(); i++) { 2644 if (i != _con && t->field_at(i) == Type::CONTROL) 2645 return this; 2646 } 2647 // Only my path is possible; I am identity on control to the jump 2648 return in(0)->in(0); 2649 } 2650 2651 2652 #ifndef PRODUCT 2653 void CatchProjNode::dump_spec(outputStream *st) const { 2654 ProjNode::dump_spec(st); 2655 st->print("@bci %d ",_handler_bci); 2656 } 2657 #endif 2658 2659 //============================================================================= 2660 //------------------------------Identity--------------------------------------- 2661 // Check for CreateEx being Identity. 2662 Node* CreateExNode::Identity(PhaseGVN* phase) { 2663 if( phase->type(in(1)) == Type::TOP ) return in(1); 2664 if( phase->type(in(0)) == Type::TOP ) return in(0); 2665 // We only come from CatchProj, unless the CatchProj goes away. 2666 // If the CatchProj is optimized away, then we just carry the 2667 // exception oop through. 2668 CallNode *call = in(1)->in(0)->as_Call(); 2669 2670 return ( in(0)->is_CatchProj() && in(0)->in(0)->in(1) == in(1) ) 2671 ? this 2672 : call->in(TypeFunc::Parms); 2673 } 2674 2675 //============================================================================= 2676 //------------------------------Value------------------------------------------ 2677 // Check for being unreachable. 2678 const Type* NeverBranchNode::Value(PhaseGVN* phase) const { 2679 if (!in(0) || in(0)->is_top()) return Type::TOP; 2680 return bottom_type(); 2681 } 2682 2683 //------------------------------Ideal------------------------------------------ 2684 // Check for no longer being part of a loop 2685 Node *NeverBranchNode::Ideal(PhaseGVN *phase, bool can_reshape) { 2686 if (can_reshape && !in(0)->is_Loop()) { 2687 // Dead code elimination can sometimes delete this projection so 2688 // if it's not there, there's nothing to do. 2689 Node* fallthru = proj_out_or_null(0); 2690 if (fallthru != NULL) { 2691 phase->is_IterGVN()->replace_node(fallthru, in(0)); 2692 } 2693 return phase->C->top(); 2694 } 2695 return NULL; 2696 } 2697 2698 #ifndef PRODUCT 2699 void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const { 2700 st->print("%s", Name()); 2701 } 2702 #endif