1 /* 2 * Copyright (c) 1997, 2015, 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 "memory/allocation.inline.hpp" 28 #include "oops/objArrayKlass.hpp" 29 #include "opto/addnode.hpp" 30 #include "opto/cfgnode.hpp" 31 #include "opto/connode.hpp" 32 #include "opto/convertnode.hpp" 33 #include "opto/loopnode.hpp" 34 #include "opto/machnode.hpp" 35 #include "opto/movenode.hpp" 36 #include "opto/narrowptrnode.hpp" 37 #include "opto/mulnode.hpp" 38 #include "opto/phaseX.hpp" 39 #include "opto/regmask.hpp" 40 #include "opto/runtime.hpp" 41 #include "opto/subnode.hpp" 42 43 // Portions of code courtesy of Clifford Click 44 45 // Optimization - Graph Style 46 47 //============================================================================= 48 //------------------------------Value------------------------------------------ 49 // Compute the type of the RegionNode. 50 const Type *RegionNode::Value( PhaseTransform *phase ) const { 51 for( uint i=1; i<req(); ++i ) { // For all paths in 52 Node *n = in(i); // Get Control source 53 if( !n ) continue; // Missing inputs are TOP 54 if( phase->type(n) == Type::CONTROL ) 55 return Type::CONTROL; 56 } 57 return Type::TOP; // All paths dead? Then so are we 58 } 59 60 //------------------------------Identity--------------------------------------- 61 // Check for Region being Identity. 62 Node *RegionNode::Identity( PhaseTransform *phase ) { 63 // Cannot have Region be an identity, even if it has only 1 input. 64 // Phi users cannot have their Region input folded away for them, 65 // since they need to select the proper data input 66 return this; 67 } 68 69 //------------------------------merge_region----------------------------------- 70 // If a Region flows into a Region, merge into one big happy merge. This is 71 // hard to do if there is stuff that has to happen 72 static Node *merge_region(RegionNode *region, PhaseGVN *phase) { 73 if( region->Opcode() != Op_Region ) // Do not do to LoopNodes 74 return NULL; 75 Node *progress = NULL; // Progress flag 76 PhaseIterGVN *igvn = phase->is_IterGVN(); 77 78 uint rreq = region->req(); 79 for( uint i = 1; i < rreq; i++ ) { 80 Node *r = region->in(i); 81 if( r && r->Opcode() == Op_Region && // Found a region? 82 r->in(0) == r && // Not already collapsed? 83 r != region && // Avoid stupid situations 84 r->outcnt() == 2 ) { // Self user and 'region' user only? 85 assert(!r->as_Region()->has_phi(), "no phi users"); 86 if( !progress ) { // No progress 87 if (region->has_phi()) { 88 return NULL; // Only flatten if no Phi users 89 // igvn->hash_delete( phi ); 90 } 91 igvn->hash_delete( region ); 92 progress = region; // Making progress 93 } 94 igvn->hash_delete( r ); 95 96 // Append inputs to 'r' onto 'region' 97 for( uint j = 1; j < r->req(); j++ ) { 98 // Move an input from 'r' to 'region' 99 region->add_req(r->in(j)); 100 r->set_req(j, phase->C->top()); 101 // Update phis of 'region' 102 //for( uint k = 0; k < max; k++ ) { 103 // Node *phi = region->out(k); 104 // if( phi->is_Phi() ) { 105 // phi->add_req(phi->in(i)); 106 // } 107 //} 108 109 rreq++; // One more input to Region 110 } // Found a region to merge into Region 111 igvn->_worklist.push(r); 112 // Clobber pointer to the now dead 'r' 113 region->set_req(i, phase->C->top()); 114 } 115 } 116 117 return progress; 118 } 119 120 121 122 //--------------------------------has_phi-------------------------------------- 123 // Helper function: Return any PhiNode that uses this region or NULL 124 PhiNode* RegionNode::has_phi() const { 125 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 126 Node* phi = fast_out(i); 127 if (phi->is_Phi()) { // Check for Phi users 128 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); 129 return phi->as_Phi(); // this one is good enough 130 } 131 } 132 133 return NULL; 134 } 135 136 137 //-----------------------------has_unique_phi---------------------------------- 138 // Helper function: Return the only PhiNode that uses this region or NULL 139 PhiNode* RegionNode::has_unique_phi() const { 140 // Check that only one use is a Phi 141 PhiNode* only_phi = NULL; 142 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 143 Node* phi = fast_out(i); 144 if (phi->is_Phi()) { // Check for Phi users 145 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); 146 if (only_phi == NULL) { 147 only_phi = phi->as_Phi(); 148 } else { 149 return NULL; // multiple phis 150 } 151 } 152 } 153 154 return only_phi; 155 } 156 157 158 //------------------------------check_phi_clipping----------------------------- 159 // Helper function for RegionNode's identification of FP clipping 160 // Check inputs to the Phi 161 static bool check_phi_clipping( PhiNode *phi, ConNode * &min, uint &min_idx, ConNode * &max, uint &max_idx, Node * &val, uint &val_idx ) { 162 min = NULL; 163 max = NULL; 164 val = NULL; 165 min_idx = 0; 166 max_idx = 0; 167 val_idx = 0; 168 uint phi_max = phi->req(); 169 if( phi_max == 4 ) { 170 for( uint j = 1; j < phi_max; ++j ) { 171 Node *n = phi->in(j); 172 int opcode = n->Opcode(); 173 switch( opcode ) { 174 case Op_ConI: 175 { 176 if( min == NULL ) { 177 min = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; 178 min_idx = j; 179 } else { 180 max = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; 181 max_idx = j; 182 if( min->get_int() > max->get_int() ) { 183 // Swap min and max 184 ConNode *temp; 185 uint temp_idx; 186 temp = min; min = max; max = temp; 187 temp_idx = min_idx; min_idx = max_idx; max_idx = temp_idx; 188 } 189 } 190 } 191 break; 192 default: 193 { 194 val = n; 195 val_idx = j; 196 } 197 break; 198 } 199 } 200 } 201 return ( min && max && val && (min->get_int() <= 0) && (max->get_int() >=0) ); 202 } 203 204 205 //------------------------------check_if_clipping------------------------------ 206 // Helper function for RegionNode's identification of FP clipping 207 // Check that inputs to Region come from two IfNodes, 208 // 209 // If 210 // False True 211 // If | 212 // False True | 213 // | | | 214 // RegionNode_inputs 215 // 216 static bool check_if_clipping( const RegionNode *region, IfNode * &bot_if, IfNode * &top_if ) { 217 top_if = NULL; 218 bot_if = NULL; 219 220 // Check control structure above RegionNode for (if ( if ) ) 221 Node *in1 = region->in(1); 222 Node *in2 = region->in(2); 223 Node *in3 = region->in(3); 224 // Check that all inputs are projections 225 if( in1->is_Proj() && in2->is_Proj() && in3->is_Proj() ) { 226 Node *in10 = in1->in(0); 227 Node *in20 = in2->in(0); 228 Node *in30 = in3->in(0); 229 // Check that #1 and #2 are ifTrue and ifFalse from same If 230 if( in10 != NULL && in10->is_If() && 231 in20 != NULL && in20->is_If() && 232 in30 != NULL && in30->is_If() && in10 == in20 && 233 (in1->Opcode() != in2->Opcode()) ) { 234 Node *in100 = in10->in(0); 235 Node *in1000 = (in100 != NULL && in100->is_Proj()) ? in100->in(0) : NULL; 236 // Check that control for in10 comes from other branch of IF from in3 237 if( in1000 != NULL && in1000->is_If() && 238 in30 == in1000 && (in3->Opcode() != in100->Opcode()) ) { 239 // Control pattern checks 240 top_if = (IfNode*)in1000; 241 bot_if = (IfNode*)in10; 242 } 243 } 244 } 245 246 return (top_if != NULL); 247 } 248 249 250 //------------------------------check_convf2i_clipping------------------------- 251 // Helper function for RegionNode's identification of FP clipping 252 // Verify that the value input to the phi comes from "ConvF2I; LShift; RShift" 253 static bool check_convf2i_clipping( PhiNode *phi, uint idx, ConvF2INode * &convf2i, Node *min, Node *max) { 254 convf2i = NULL; 255 256 // Check for the RShiftNode 257 Node *rshift = phi->in(idx); 258 assert( rshift, "Previous checks ensure phi input is present"); 259 if( rshift->Opcode() != Op_RShiftI ) { return false; } 260 261 // Check for the LShiftNode 262 Node *lshift = rshift->in(1); 263 assert( lshift, "Previous checks ensure phi input is present"); 264 if( lshift->Opcode() != Op_LShiftI ) { return false; } 265 266 // Check for the ConvF2INode 267 Node *conv = lshift->in(1); 268 if( conv->Opcode() != Op_ConvF2I ) { return false; } 269 270 // Check that shift amounts are only to get sign bits set after F2I 271 jint max_cutoff = max->get_int(); 272 jint min_cutoff = min->get_int(); 273 jint left_shift = lshift->in(2)->get_int(); 274 jint right_shift = rshift->in(2)->get_int(); 275 jint max_post_shift = nth_bit(BitsPerJavaInteger - left_shift - 1); 276 if( left_shift != right_shift || 277 0 > left_shift || left_shift >= BitsPerJavaInteger || 278 max_post_shift < max_cutoff || 279 max_post_shift < -min_cutoff ) { 280 // Shifts are necessary but current transformation eliminates them 281 return false; 282 } 283 284 // OK to return the result of ConvF2I without shifting 285 convf2i = (ConvF2INode*)conv; 286 return true; 287 } 288 289 290 //------------------------------check_compare_clipping------------------------- 291 // Helper function for RegionNode's identification of FP clipping 292 static bool check_compare_clipping( bool less_than, IfNode *iff, ConNode *limit, Node * & input ) { 293 Node *i1 = iff->in(1); 294 if ( !i1->is_Bool() ) { return false; } 295 BoolNode *bool1 = i1->as_Bool(); 296 if( less_than && bool1->_test._test != BoolTest::le ) { return false; } 297 else if( !less_than && bool1->_test._test != BoolTest::lt ) { return false; } 298 const Node *cmpF = bool1->in(1); 299 if( cmpF->Opcode() != Op_CmpF ) { return false; } 300 // Test that the float value being compared against 301 // is equivalent to the int value used as a limit 302 Node *nodef = cmpF->in(2); 303 if( nodef->Opcode() != Op_ConF ) { return false; } 304 jfloat conf = nodef->getf(); 305 jint coni = limit->get_int(); 306 if( ((int)conf) != coni ) { return false; } 307 input = cmpF->in(1); 308 return true; 309 } 310 311 //------------------------------is_unreachable_region-------------------------- 312 // Find if the Region node is reachable from the root. 313 bool RegionNode::is_unreachable_region(PhaseGVN *phase) const { 314 assert(req() == 2, ""); 315 316 // First, cut the simple case of fallthrough region when NONE of 317 // region's phis references itself directly or through a data node. 318 uint max = outcnt(); 319 uint i; 320 for (i = 0; i < max; i++) { 321 Node* phi = raw_out(i); 322 if (phi != NULL && phi->is_Phi()) { 323 assert(phase->eqv(phi->in(0), this) && phi->req() == 2, ""); 324 if (phi->outcnt() == 0) 325 continue; // Safe case - no loops 326 if (phi->outcnt() == 1) { 327 Node* u = phi->raw_out(0); 328 // Skip if only one use is an other Phi or Call or Uncommon trap. 329 // It is safe to consider this case as fallthrough. 330 if (u != NULL && (u->is_Phi() || u->is_CFG())) 331 continue; 332 } 333 // Check when phi references itself directly or through an other node. 334 if (phi->as_Phi()->simple_data_loop_check(phi->in(1)) >= PhiNode::Unsafe) 335 break; // Found possible unsafe data loop. 336 } 337 } 338 if (i >= max) 339 return false; // An unsafe case was NOT found - don't need graph walk. 340 341 // Unsafe case - check if the Region node is reachable from root. 342 ResourceMark rm; 343 344 Arena *a = Thread::current()->resource_area(); 345 Node_List nstack(a); 346 VectorSet visited(a); 347 348 // Mark all control nodes reachable from root outputs 349 Node *n = (Node*)phase->C->root(); 350 nstack.push(n); 351 visited.set(n->_idx); 352 while (nstack.size() != 0) { 353 n = nstack.pop(); 354 uint max = n->outcnt(); 355 for (uint i = 0; i < max; i++) { 356 Node* m = n->raw_out(i); 357 if (m != NULL && m->is_CFG()) { 358 if (phase->eqv(m, this)) { 359 return false; // We reached the Region node - it is not dead. 360 } 361 if (!visited.test_set(m->_idx)) 362 nstack.push(m); 363 } 364 } 365 } 366 367 return true; // The Region node is unreachable - it is dead. 368 } 369 370 bool RegionNode::try_clean_mem_phi(PhaseGVN *phase) { 371 // Incremental inlining + PhaseStringOpts sometimes produce: 372 // 373 // cmpP with 1 top input 374 // | 375 // If 376 // / \ 377 // IfFalse IfTrue /- Some Node 378 // \ / / / 379 // Region / /-MergeMem 380 // \---Phi 381 // 382 // 383 // It's expected by PhaseStringOpts that the Region goes away and is 384 // replaced by If's control input but because there's still a Phi, 385 // the Region stays in the graph. The top input from the cmpP is 386 // propagated forward and a subgraph that is useful goes away. The 387 // code below replaces the Phi with the MergeMem so that the Region 388 // is simplified. 389 390 PhiNode* phi = has_unique_phi(); 391 if (phi && phi->type() == Type::MEMORY && req() == 3 && phi->is_diamond_phi(true)) { 392 MergeMemNode* m = NULL; 393 assert(phi->req() == 3, "same as region"); 394 for (uint i = 1; i < 3; ++i) { 395 Node *mem = phi->in(i); 396 if (mem && mem->is_MergeMem() && in(i)->outcnt() == 1) { 397 // Nothing is control-dependent on path #i except the region itself. 398 m = mem->as_MergeMem(); 399 uint j = 3 - i; 400 Node* other = phi->in(j); 401 if (other && other == m->base_memory()) { 402 // m is a successor memory to other, and is not pinned inside the diamond, so push it out. 403 // This will allow the diamond to collapse completely. 404 phase->is_IterGVN()->replace_node(phi, m); 405 return true; 406 } 407 } 408 } 409 } 410 return false; 411 } 412 413 //------------------------------Ideal------------------------------------------ 414 // Return a node which is more "ideal" than the current node. Must preserve 415 // the CFG, but we can still strip out dead paths. 416 Node *RegionNode::Ideal(PhaseGVN *phase, bool can_reshape) { 417 if( !can_reshape && !in(0) ) return NULL; // Already degraded to a Copy 418 assert(!in(0) || !in(0)->is_Root(), "not a specially hidden merge"); 419 420 // Check for RegionNode with no Phi users and both inputs come from either 421 // arm of the same IF. If found, then the control-flow split is useless. 422 bool has_phis = false; 423 if (can_reshape) { // Need DU info to check for Phi users 424 has_phis = (has_phi() != NULL); // Cache result 425 if (has_phis && try_clean_mem_phi(phase)) { 426 has_phis = false; 427 } 428 429 if (!has_phis) { // No Phi users? Nothing merging? 430 for (uint i = 1; i < req()-1; i++) { 431 Node *if1 = in(i); 432 if( !if1 ) continue; 433 Node *iff = if1->in(0); 434 if( !iff || !iff->is_If() ) continue; 435 for( uint j=i+1; j<req(); j++ ) { 436 if( in(j) && in(j)->in(0) == iff && 437 if1->Opcode() != in(j)->Opcode() ) { 438 // Add the IF Projections to the worklist. They (and the IF itself) 439 // will be eliminated if dead. 440 phase->is_IterGVN()->add_users_to_worklist(iff); 441 set_req(i, iff->in(0));// Skip around the useless IF diamond 442 set_req(j, NULL); 443 return this; // Record progress 444 } 445 } 446 } 447 } 448 } 449 450 // Remove TOP or NULL input paths. If only 1 input path remains, this Region 451 // degrades to a copy. 452 bool add_to_worklist = false; 453 bool modified = false; 454 int cnt = 0; // Count of values merging 455 DEBUG_ONLY( int cnt_orig = req(); ) // Save original inputs count 456 int del_it = 0; // The last input path we delete 457 // For all inputs... 458 for( uint i=1; i<req(); ++i ){// For all paths in 459 Node *n = in(i); // Get the input 460 if( n != NULL ) { 461 // Remove useless control copy inputs 462 if( n->is_Region() && n->as_Region()->is_copy() ) { 463 set_req(i, n->nonnull_req()); 464 modified = true; 465 i--; 466 continue; 467 } 468 if( n->is_Proj() ) { // Remove useless rethrows 469 Node *call = n->in(0); 470 if (call->is_Call() && call->as_Call()->entry_point() == OptoRuntime::rethrow_stub()) { 471 set_req(i, call->in(0)); 472 modified = true; 473 i--; 474 continue; 475 } 476 } 477 if( phase->type(n) == Type::TOP ) { 478 set_req(i, NULL); // Ignore TOP inputs 479 modified = true; 480 i--; 481 continue; 482 } 483 cnt++; // One more value merging 484 485 } else if (can_reshape) { // Else found dead path with DU info 486 PhaseIterGVN *igvn = phase->is_IterGVN(); 487 del_req(i); // Yank path from self 488 del_it = i; 489 uint max = outcnt(); 490 DUIterator j; 491 bool progress = true; 492 while(progress) { // Need to establish property over all users 493 progress = false; 494 for (j = outs(); has_out(j); j++) { 495 Node *n = out(j); 496 if( n->req() != req() && n->is_Phi() ) { 497 assert( n->in(0) == this, "" ); 498 igvn->hash_delete(n); // Yank from hash before hacking edges 499 n->set_req_X(i,NULL,igvn);// Correct DU info 500 n->del_req(i); // Yank path from Phis 501 if( max != outcnt() ) { 502 progress = true; 503 j = refresh_out_pos(j); 504 max = outcnt(); 505 } 506 } 507 } 508 } 509 add_to_worklist = true; 510 i--; 511 } 512 } 513 514 if (can_reshape && cnt == 1) { 515 // Is it dead loop? 516 // If it is LoopNopde it had 2 (+1 itself) inputs and 517 // one of them was cut. The loop is dead if it was EntryContol. 518 // Loop node may have only one input because entry path 519 // is removed in PhaseIdealLoop::Dominators(). 520 assert(!this->is_Loop() || cnt_orig <= 3, "Loop node should have 3 or less inputs"); 521 if (this->is_Loop() && (del_it == LoopNode::EntryControl || 522 del_it == 0 && is_unreachable_region(phase)) || 523 !this->is_Loop() && has_phis && is_unreachable_region(phase)) { 524 // Yes, the region will be removed during the next step below. 525 // Cut the backedge input and remove phis since no data paths left. 526 // We don't cut outputs to other nodes here since we need to put them 527 // on the worklist. 528 del_req(1); 529 cnt = 0; 530 assert( req() == 1, "no more inputs expected" ); 531 uint max = outcnt(); 532 bool progress = true; 533 Node *top = phase->C->top(); 534 PhaseIterGVN *igvn = phase->is_IterGVN(); 535 DUIterator j; 536 while(progress) { 537 progress = false; 538 for (j = outs(); has_out(j); j++) { 539 Node *n = out(j); 540 if( n->is_Phi() ) { 541 assert( igvn->eqv(n->in(0), this), "" ); 542 assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" ); 543 // Break dead loop data path. 544 // Eagerly replace phis with top to avoid phis copies generation. 545 igvn->replace_node(n, top); 546 if( max != outcnt() ) { 547 progress = true; 548 j = refresh_out_pos(j); 549 max = outcnt(); 550 } 551 } 552 } 553 } 554 add_to_worklist = true; 555 } 556 } 557 if (add_to_worklist) { 558 phase->is_IterGVN()->add_users_to_worklist(this); // Revisit collapsed Phis 559 } 560 561 if( cnt <= 1 ) { // Only 1 path in? 562 set_req(0, NULL); // Null control input for region copy 563 if( cnt == 0 && !can_reshape) { // Parse phase - leave the node as it is. 564 // No inputs or all inputs are NULL. 565 return NULL; 566 } else if (can_reshape) { // Optimization phase - remove the node 567 PhaseIterGVN *igvn = phase->is_IterGVN(); 568 Node *parent_ctrl; 569 if( cnt == 0 ) { 570 assert( req() == 1, "no inputs expected" ); 571 // During IGVN phase such region will be subsumed by TOP node 572 // so region's phis will have TOP as control node. 573 // Kill phis here to avoid it. PhiNode::is_copy() will be always false. 574 // Also set other user's input to top. 575 parent_ctrl = phase->C->top(); 576 } else { 577 // The fallthrough case since we already checked dead loops above. 578 parent_ctrl = in(1); 579 assert(parent_ctrl != NULL, "Region is a copy of some non-null control"); 580 assert(!igvn->eqv(parent_ctrl, this), "Close dead loop"); 581 } 582 if (!add_to_worklist) 583 igvn->add_users_to_worklist(this); // Check for further allowed opts 584 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) { 585 Node* n = last_out(i); 586 igvn->hash_delete(n); // Remove from worklist before modifying edges 587 if( n->is_Phi() ) { // Collapse all Phis 588 // Eagerly replace phis to avoid copies generation. 589 Node* in; 590 if( cnt == 0 ) { 591 assert( n->req() == 1, "No data inputs expected" ); 592 in = parent_ctrl; // replaced by top 593 } else { 594 assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" ); 595 in = n->in(1); // replaced by unique input 596 if( n->as_Phi()->is_unsafe_data_reference(in) ) 597 in = phase->C->top(); // replaced by top 598 } 599 igvn->replace_node(n, in); 600 } 601 else if( n->is_Region() ) { // Update all incoming edges 602 assert( !igvn->eqv(n, this), "Must be removed from DefUse edges"); 603 uint uses_found = 0; 604 for( uint k=1; k < n->req(); k++ ) { 605 if( n->in(k) == this ) { 606 n->set_req(k, parent_ctrl); 607 uses_found++; 608 } 609 } 610 if( uses_found > 1 ) { // (--i) done at the end of the loop. 611 i -= (uses_found - 1); 612 } 613 } 614 else { 615 assert( igvn->eqv(n->in(0), this), "Expect RegionNode to be control parent"); 616 n->set_req(0, parent_ctrl); 617 } 618 #ifdef ASSERT 619 for( uint k=0; k < n->req(); k++ ) { 620 assert( !igvn->eqv(n->in(k), this), "All uses of RegionNode should be gone"); 621 } 622 #endif 623 } 624 // Remove the RegionNode itself from DefUse info 625 igvn->remove_dead_node(this); 626 return NULL; 627 } 628 return this; // Record progress 629 } 630 631 632 // If a Region flows into a Region, merge into one big happy merge. 633 if (can_reshape) { 634 Node *m = merge_region(this, phase); 635 if (m != NULL) return m; 636 } 637 638 // Check if this region is the root of a clipping idiom on floats 639 if( ConvertFloat2IntClipping && can_reshape && req() == 4 ) { 640 // Check that only one use is a Phi and that it simplifies to two constants + 641 PhiNode* phi = has_unique_phi(); 642 if (phi != NULL) { // One Phi user 643 // Check inputs to the Phi 644 ConNode *min; 645 ConNode *max; 646 Node *val; 647 uint min_idx; 648 uint max_idx; 649 uint val_idx; 650 if( check_phi_clipping( phi, min, min_idx, max, max_idx, val, val_idx ) ) { 651 IfNode *top_if; 652 IfNode *bot_if; 653 if( check_if_clipping( this, bot_if, top_if ) ) { 654 // Control pattern checks, now verify compares 655 Node *top_in = NULL; // value being compared against 656 Node *bot_in = NULL; 657 if( check_compare_clipping( true, bot_if, min, bot_in ) && 658 check_compare_clipping( false, top_if, max, top_in ) ) { 659 if( bot_in == top_in ) { 660 PhaseIterGVN *gvn = phase->is_IterGVN(); 661 assert( gvn != NULL, "Only had DefUse info in IterGVN"); 662 // Only remaining check is that bot_in == top_in == (Phi's val + mods) 663 664 // Check for the ConvF2INode 665 ConvF2INode *convf2i; 666 if( check_convf2i_clipping( phi, val_idx, convf2i, min, max ) && 667 convf2i->in(1) == bot_in ) { 668 // Matched pattern, including LShiftI; RShiftI, replace with integer compares 669 // max test 670 Node *cmp = gvn->register_new_node_with_optimizer(new CmpINode( convf2i, min )); 671 Node *boo = gvn->register_new_node_with_optimizer(new BoolNode( cmp, BoolTest::lt )); 672 IfNode *iff = (IfNode*)gvn->register_new_node_with_optimizer(new IfNode( top_if->in(0), boo, PROB_UNLIKELY_MAG(5), top_if->_fcnt )); 673 Node *if_min= gvn->register_new_node_with_optimizer(new IfTrueNode (iff)); 674 Node *ifF = gvn->register_new_node_with_optimizer(new IfFalseNode(iff)); 675 // min test 676 cmp = gvn->register_new_node_with_optimizer(new CmpINode( convf2i, max )); 677 boo = gvn->register_new_node_with_optimizer(new BoolNode( cmp, BoolTest::gt )); 678 iff = (IfNode*)gvn->register_new_node_with_optimizer(new IfNode( ifF, boo, PROB_UNLIKELY_MAG(5), bot_if->_fcnt )); 679 Node *if_max= gvn->register_new_node_with_optimizer(new IfTrueNode (iff)); 680 ifF = gvn->register_new_node_with_optimizer(new IfFalseNode(iff)); 681 // update input edges to region node 682 set_req_X( min_idx, if_min, gvn ); 683 set_req_X( max_idx, if_max, gvn ); 684 set_req_X( val_idx, ifF, gvn ); 685 // remove unnecessary 'LShiftI; RShiftI' idiom 686 gvn->hash_delete(phi); 687 phi->set_req_X( val_idx, convf2i, gvn ); 688 gvn->hash_find_insert(phi); 689 // Return transformed region node 690 return this; 691 } 692 } 693 } 694 } 695 } 696 } 697 } 698 699 return modified ? this : NULL; 700 } 701 702 703 704 const RegMask &RegionNode::out_RegMask() const { 705 return RegMask::Empty; 706 } 707 708 // Find the one non-null required input. RegionNode only 709 Node *Node::nonnull_req() const { 710 assert( is_Region(), "" ); 711 for( uint i = 1; i < _cnt; i++ ) 712 if( in(i) ) 713 return in(i); 714 ShouldNotReachHere(); 715 return NULL; 716 } 717 718 719 //============================================================================= 720 // note that these functions assume that the _adr_type field is flattened 721 uint PhiNode::hash() const { 722 const Type* at = _adr_type; 723 return TypeNode::hash() + (at ? at->hash() : 0); 724 } 725 uint PhiNode::cmp( const Node &n ) const { 726 return TypeNode::cmp(n) && _adr_type == ((PhiNode&)n)._adr_type; 727 } 728 static inline 729 const TypePtr* flatten_phi_adr_type(const TypePtr* at) { 730 if (at == NULL || at == TypePtr::BOTTOM) return at; 731 return Compile::current()->alias_type(at)->adr_type(); 732 } 733 734 //----------------------------make--------------------------------------------- 735 // create a new phi with edges matching r and set (initially) to x 736 PhiNode* PhiNode::make(Node* r, Node* x, const Type *t, const TypePtr* at) { 737 uint preds = r->req(); // Number of predecessor paths 738 assert(t != Type::MEMORY || at == flatten_phi_adr_type(at), "flatten at"); 739 PhiNode* p = new PhiNode(r, t, at); 740 for (uint j = 1; j < preds; j++) { 741 // Fill in all inputs, except those which the region does not yet have 742 if (r->in(j) != NULL) 743 p->init_req(j, x); 744 } 745 return p; 746 } 747 PhiNode* PhiNode::make(Node* r, Node* x) { 748 const Type* t = x->bottom_type(); 749 const TypePtr* at = NULL; 750 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); 751 return make(r, x, t, at); 752 } 753 PhiNode* PhiNode::make_blank(Node* r, Node* x) { 754 const Type* t = x->bottom_type(); 755 const TypePtr* at = NULL; 756 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); 757 return new PhiNode(r, t, at); 758 } 759 760 761 //------------------------slice_memory----------------------------------------- 762 // create a new phi with narrowed memory type 763 PhiNode* PhiNode::slice_memory(const TypePtr* adr_type) const { 764 PhiNode* mem = (PhiNode*) clone(); 765 *(const TypePtr**)&mem->_adr_type = adr_type; 766 // convert self-loops, or else we get a bad graph 767 for (uint i = 1; i < req(); i++) { 768 if ((const Node*)in(i) == this) mem->set_req(i, mem); 769 } 770 mem->verify_adr_type(); 771 return mem; 772 } 773 774 //------------------------split_out_instance----------------------------------- 775 // Split out an instance type from a bottom phi. 776 PhiNode* PhiNode::split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const { 777 const TypeOopPtr *t_oop = at->isa_oopptr(); 778 assert(t_oop != NULL && t_oop->is_known_instance(), "expecting instance oopptr"); 779 const TypePtr *t = adr_type(); 780 assert(type() == Type::MEMORY && 781 (t == TypePtr::BOTTOM || t == TypeRawPtr::BOTTOM || 782 t->isa_oopptr() && !t->is_oopptr()->is_known_instance() && 783 t->is_oopptr()->cast_to_exactness(true) 784 ->is_oopptr()->cast_to_ptr_type(t_oop->ptr()) 785 ->is_oopptr()->cast_to_instance_id(t_oop->instance_id()) == t_oop), 786 "bottom or raw memory required"); 787 788 // Check if an appropriate node already exists. 789 Node *region = in(0); 790 for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) { 791 Node* use = region->fast_out(k); 792 if( use->is_Phi()) { 793 PhiNode *phi2 = use->as_Phi(); 794 if (phi2->type() == Type::MEMORY && phi2->adr_type() == at) { 795 return phi2; 796 } 797 } 798 } 799 Compile *C = igvn->C; 800 Arena *a = Thread::current()->resource_area(); 801 Node_Array node_map = new Node_Array(a); 802 Node_Stack stack(a, C->unique() >> 4); 803 PhiNode *nphi = slice_memory(at); 804 igvn->register_new_node_with_optimizer( nphi ); 805 node_map.map(_idx, nphi); 806 stack.push((Node *)this, 1); 807 while(!stack.is_empty()) { 808 PhiNode *ophi = stack.node()->as_Phi(); 809 uint i = stack.index(); 810 assert(i >= 1, "not control edge"); 811 stack.pop(); 812 nphi = node_map[ophi->_idx]->as_Phi(); 813 for (; i < ophi->req(); i++) { 814 Node *in = ophi->in(i); 815 if (in == NULL || igvn->type(in) == Type::TOP) 816 continue; 817 Node *opt = MemNode::optimize_simple_memory_chain(in, t_oop, NULL, igvn); 818 PhiNode *optphi = opt->is_Phi() ? opt->as_Phi() : NULL; 819 if (optphi != NULL && optphi->adr_type() == TypePtr::BOTTOM) { 820 opt = node_map[optphi->_idx]; 821 if (opt == NULL) { 822 stack.push(ophi, i); 823 nphi = optphi->slice_memory(at); 824 igvn->register_new_node_with_optimizer( nphi ); 825 node_map.map(optphi->_idx, nphi); 826 ophi = optphi; 827 i = 0; // will get incremented at top of loop 828 continue; 829 } 830 } 831 nphi->set_req(i, opt); 832 } 833 } 834 return nphi; 835 } 836 837 //------------------------verify_adr_type-------------------------------------- 838 #ifdef ASSERT 839 void PhiNode::verify_adr_type(VectorSet& visited, const TypePtr* at) const { 840 if (visited.test_set(_idx)) return; //already visited 841 842 // recheck constructor invariants: 843 verify_adr_type(false); 844 845 // recheck local phi/phi consistency: 846 assert(_adr_type == at || _adr_type == TypePtr::BOTTOM, 847 "adr_type must be consistent across phi nest"); 848 849 // walk around 850 for (uint i = 1; i < req(); i++) { 851 Node* n = in(i); 852 if (n == NULL) continue; 853 const Node* np = in(i); 854 if (np->is_Phi()) { 855 np->as_Phi()->verify_adr_type(visited, at); 856 } else if (n->bottom_type() == Type::TOP 857 || (n->is_Mem() && n->in(MemNode::Address)->bottom_type() == Type::TOP)) { 858 // ignore top inputs 859 } else { 860 const TypePtr* nat = flatten_phi_adr_type(n->adr_type()); 861 // recheck phi/non-phi consistency at leaves: 862 assert((nat != NULL) == (at != NULL), ""); 863 assert(nat == at || nat == TypePtr::BOTTOM, 864 "adr_type must be consistent at leaves of phi nest"); 865 } 866 } 867 } 868 869 // Verify a whole nest of phis rooted at this one. 870 void PhiNode::verify_adr_type(bool recursive) const { 871 if (is_error_reported()) return; // muzzle asserts when debugging an error 872 if (Node::in_dump()) return; // muzzle asserts when printing 873 874 assert((_type == Type::MEMORY) == (_adr_type != NULL), "adr_type for memory phis only"); 875 876 if (!VerifyAliases) return; // verify thoroughly only if requested 877 878 assert(_adr_type == flatten_phi_adr_type(_adr_type), 879 "Phi::adr_type must be pre-normalized"); 880 881 if (recursive) { 882 VectorSet visited(Thread::current()->resource_area()); 883 verify_adr_type(visited, _adr_type); 884 } 885 } 886 #endif 887 888 889 //------------------------------Value------------------------------------------ 890 // Compute the type of the PhiNode 891 const Type *PhiNode::Value( PhaseTransform *phase ) const { 892 Node *r = in(0); // RegionNode 893 if( !r ) // Copy or dead 894 return in(1) ? phase->type(in(1)) : Type::TOP; 895 896 // Note: During parsing, phis are often transformed before their regions. 897 // This means we have to use type_or_null to defend against untyped regions. 898 if( phase->type_or_null(r) == Type::TOP ) // Dead code? 899 return Type::TOP; 900 901 // Check for trip-counted loop. If so, be smarter. 902 CountedLoopNode *l = r->is_CountedLoop() ? r->as_CountedLoop() : NULL; 903 if( l && l->can_be_counted_loop(phase) && 904 ((const Node*)l->phi() == this) ) { // Trip counted loop! 905 // protect against init_trip() or limit() returning NULL 906 const Node *init = l->init_trip(); 907 const Node *limit = l->limit(); 908 if( init != NULL && limit != NULL && l->stride_is_con() ) { 909 const TypeInt *lo = init ->bottom_type()->isa_int(); 910 const TypeInt *hi = limit->bottom_type()->isa_int(); 911 if( lo && hi ) { // Dying loops might have TOP here 912 int stride = l->stride_con(); 913 if( stride < 0 ) { // Down-counter loop 914 const TypeInt *tmp = lo; lo = hi; hi = tmp; 915 stride = -stride; 916 } 917 if( lo->_hi < hi->_lo ) // Reversed endpoints are well defined :-( 918 return TypeInt::make(lo->_lo,hi->_hi,3); 919 } 920 } 921 } 922 923 // Until we have harmony between classes and interfaces in the type 924 // lattice, we must tread carefully around phis which implicitly 925 // convert the one to the other. 926 const TypePtr* ttp = _type->make_ptr(); 927 const TypeInstPtr* ttip = (ttp != NULL) ? ttp->isa_instptr() : NULL; 928 const TypeKlassPtr* ttkp = (ttp != NULL) ? ttp->isa_klassptr() : NULL; 929 bool is_intf = false; 930 if (ttip != NULL) { 931 ciKlass* k = ttip->klass(); 932 if (k->is_loaded() && k->is_interface()) 933 is_intf = true; 934 } 935 if (ttkp != NULL) { 936 ciKlass* k = ttkp->klass(); 937 if (k->is_loaded() && k->is_interface()) 938 is_intf = true; 939 } 940 941 // Default case: merge all inputs 942 const Type *t = Type::TOP; // Merged type starting value 943 for (uint i = 1; i < req(); ++i) {// For all paths in 944 // Reachable control path? 945 if (r->in(i) && phase->type(r->in(i)) == Type::CONTROL) { 946 const Type* ti = phase->type(in(i)); 947 // We assume that each input of an interface-valued Phi is a true 948 // subtype of that interface. This might not be true of the meet 949 // of all the input types. The lattice is not distributive in 950 // such cases. Ward off asserts in type.cpp by refusing to do 951 // meets between interfaces and proper classes. 952 const TypePtr* tip = ti->make_ptr(); 953 const TypeInstPtr* tiip = (tip != NULL) ? tip->isa_instptr() : NULL; 954 if (tiip) { 955 bool ti_is_intf = false; 956 ciKlass* k = tiip->klass(); 957 if (k->is_loaded() && k->is_interface()) 958 ti_is_intf = true; 959 if (is_intf != ti_is_intf) 960 { t = _type; break; } 961 } 962 t = t->meet_speculative(ti); 963 } 964 } 965 966 // The worst-case type (from ciTypeFlow) should be consistent with "t". 967 // That is, we expect that "t->higher_equal(_type)" holds true. 968 // There are various exceptions: 969 // - Inputs which are phis might in fact be widened unnecessarily. 970 // For example, an input might be a widened int while the phi is a short. 971 // - Inputs might be BotPtrs but this phi is dependent on a null check, 972 // and postCCP has removed the cast which encodes the result of the check. 973 // - The type of this phi is an interface, and the inputs are classes. 974 // - Value calls on inputs might produce fuzzy results. 975 // (Occurrences of this case suggest improvements to Value methods.) 976 // 977 // It is not possible to see Type::BOTTOM values as phi inputs, 978 // because the ciTypeFlow pre-pass produces verifier-quality types. 979 const Type* ft = t->filter_speculative(_type); // Worst case type 980 981 #ifdef ASSERT 982 // The following logic has been moved into TypeOopPtr::filter. 983 const Type* jt = t->join_speculative(_type); 984 if( jt->empty() ) { // Emptied out??? 985 986 // Check for evil case of 't' being a class and '_type' expecting an 987 // interface. This can happen because the bytecodes do not contain 988 // enough type info to distinguish a Java-level interface variable 989 // from a Java-level object variable. If we meet 2 classes which 990 // both implement interface I, but their meet is at 'j/l/O' which 991 // doesn't implement I, we have no way to tell if the result should 992 // be 'I' or 'j/l/O'. Thus we'll pick 'j/l/O'. If this then flows 993 // into a Phi which "knows" it's an Interface type we'll have to 994 // uplift the type. 995 if( !t->empty() && ttip && ttip->is_loaded() && ttip->klass()->is_interface() ) 996 { assert(ft == _type, ""); } // Uplift to interface 997 else if( !t->empty() && ttkp && ttkp->is_loaded() && ttkp->klass()->is_interface() ) 998 { assert(ft == _type, ""); } // Uplift to interface 999 // Otherwise it's something stupid like non-overlapping int ranges 1000 // found on dying counted loops. 1001 else 1002 { assert(ft == Type::TOP, ""); } // Canonical empty value 1003 } 1004 1005 else { 1006 1007 // If we have an interface-typed Phi and we narrow to a class type, the join 1008 // should report back the class. However, if we have a J/L/Object 1009 // class-typed Phi and an interface flows in, it's possible that the meet & 1010 // join report an interface back out. This isn't possible but happens 1011 // because the type system doesn't interact well with interfaces. 1012 const TypePtr *jtp = jt->make_ptr(); 1013 const TypeInstPtr *jtip = (jtp != NULL) ? jtp->isa_instptr() : NULL; 1014 const TypeKlassPtr *jtkp = (jtp != NULL) ? jtp->isa_klassptr() : NULL; 1015 if( jtip && ttip ) { 1016 if( jtip->is_loaded() && jtip->klass()->is_interface() && 1017 ttip->is_loaded() && !ttip->klass()->is_interface() ) { 1018 assert(ft == ttip->cast_to_ptr_type(jtip->ptr()) || 1019 ft->isa_narrowoop() && ft->make_ptr() == ttip->cast_to_ptr_type(jtip->ptr()), ""); 1020 jt = ft; 1021 } 1022 } 1023 if( jtkp && ttkp ) { 1024 if( jtkp->is_loaded() && jtkp->klass()->is_interface() && 1025 !jtkp->klass_is_exact() && // Keep exact interface klass (6894807) 1026 ttkp->is_loaded() && !ttkp->klass()->is_interface() ) { 1027 assert(ft == ttkp->cast_to_ptr_type(jtkp->ptr()) || 1028 ft->isa_narrowklass() && ft->make_ptr() == ttkp->cast_to_ptr_type(jtkp->ptr()), ""); 1029 jt = ft; 1030 } 1031 } 1032 if (jt != ft && jt->base() == ft->base()) { 1033 if (jt->isa_int() && 1034 jt->is_int()->_lo == ft->is_int()->_lo && 1035 jt->is_int()->_hi == ft->is_int()->_hi) 1036 jt = ft; 1037 if (jt->isa_long() && 1038 jt->is_long()->_lo == ft->is_long()->_lo && 1039 jt->is_long()->_hi == ft->is_long()->_hi) 1040 jt = ft; 1041 } 1042 if (jt != ft) { 1043 tty->print("merge type: "); t->dump(); tty->cr(); 1044 tty->print("kill type: "); _type->dump(); tty->cr(); 1045 tty->print("join type: "); jt->dump(); tty->cr(); 1046 tty->print("filter type: "); ft->dump(); tty->cr(); 1047 } 1048 assert(jt == ft, ""); 1049 } 1050 #endif //ASSERT 1051 1052 // Deal with conversion problems found in data loops. 1053 ft = phase->saturate(ft, phase->type_or_null(this), _type); 1054 1055 return ft; 1056 } 1057 1058 1059 //------------------------------is_diamond_phi--------------------------------- 1060 // Does this Phi represent a simple well-shaped diamond merge? Return the 1061 // index of the true path or 0 otherwise. 1062 // If check_control_only is true, do not inspect the If node at the 1063 // top, and return -1 (not an edge number) on success. 1064 int PhiNode::is_diamond_phi(bool check_control_only) const { 1065 // Check for a 2-path merge 1066 Node *region = in(0); 1067 if( !region ) return 0; 1068 if( region->req() != 3 ) return 0; 1069 if( req() != 3 ) return 0; 1070 // Check that both paths come from the same If 1071 Node *ifp1 = region->in(1); 1072 Node *ifp2 = region->in(2); 1073 if( !ifp1 || !ifp2 ) return 0; 1074 Node *iff = ifp1->in(0); 1075 if( !iff || !iff->is_If() ) return 0; 1076 if( iff != ifp2->in(0) ) return 0; 1077 if (check_control_only) return -1; 1078 // Check for a proper bool/cmp 1079 const Node *b = iff->in(1); 1080 if( !b->is_Bool() ) return 0; 1081 const Node *cmp = b->in(1); 1082 if( !cmp->is_Cmp() ) return 0; 1083 1084 // Check for branching opposite expected 1085 if( ifp2->Opcode() == Op_IfTrue ) { 1086 assert( ifp1->Opcode() == Op_IfFalse, "" ); 1087 return 2; 1088 } else { 1089 assert( ifp1->Opcode() == Op_IfTrue, "" ); 1090 return 1; 1091 } 1092 } 1093 1094 //----------------------------check_cmove_id----------------------------------- 1095 // Check for CMove'ing a constant after comparing against the constant. 1096 // Happens all the time now, since if we compare equality vs a constant in 1097 // the parser, we "know" the variable is constant on one path and we force 1098 // it. Thus code like "if( x==0 ) {/*EMPTY*/}" ends up inserting a 1099 // conditional move: "x = (x==0)?0:x;". Yucko. This fix is slightly more 1100 // general in that we don't need constants. Since CMove's are only inserted 1101 // in very special circumstances, we do it here on generic Phi's. 1102 Node* PhiNode::is_cmove_id(PhaseTransform* phase, int true_path) { 1103 assert(true_path !=0, "only diamond shape graph expected"); 1104 1105 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1106 // phi->region->if_proj->ifnode->bool->cmp 1107 Node* region = in(0); 1108 Node* iff = region->in(1)->in(0); 1109 BoolNode* b = iff->in(1)->as_Bool(); 1110 Node* cmp = b->in(1); 1111 Node* tval = in(true_path); 1112 Node* fval = in(3-true_path); 1113 Node* id = CMoveNode::is_cmove_id(phase, cmp, tval, fval, b); 1114 if (id == NULL) 1115 return NULL; 1116 1117 // Either value might be a cast that depends on a branch of 'iff'. 1118 // Since the 'id' value will float free of the diamond, either 1119 // decast or return failure. 1120 Node* ctl = id->in(0); 1121 if (ctl != NULL && ctl->in(0) == iff) { 1122 if (id->is_ConstraintCast()) { 1123 return id->in(1); 1124 } else { 1125 // Don't know how to disentangle this value. 1126 return NULL; 1127 } 1128 } 1129 1130 return id; 1131 } 1132 1133 //------------------------------Identity--------------------------------------- 1134 // Check for Region being Identity. 1135 Node *PhiNode::Identity( PhaseTransform *phase ) { 1136 // Check for no merging going on 1137 // (There used to be special-case code here when this->region->is_Loop. 1138 // It would check for a tributary phi on the backedge that the main phi 1139 // trivially, perhaps with a single cast. The unique_input method 1140 // does all this and more, by reducing such tributaries to 'this'.) 1141 Node* uin = unique_input(phase); 1142 if (uin != NULL) { 1143 return uin; 1144 } 1145 1146 int true_path = is_diamond_phi(); 1147 if (true_path != 0) { 1148 Node* id = is_cmove_id(phase, true_path); 1149 if (id != NULL) return id; 1150 } 1151 1152 return this; // No identity 1153 } 1154 1155 //-----------------------------unique_input------------------------------------ 1156 // Find the unique value, discounting top, self-loops, and casts. 1157 // Return top if there are no inputs, and self if there are multiple. 1158 Node* PhiNode::unique_input(PhaseTransform* phase) { 1159 // 1) One unique direct input, or 1160 // 2) some of the inputs have an intervening ConstraintCast and 1161 // the type of input is the same or sharper (more specific) 1162 // than the phi's type. 1163 // 3) an input is a self loop 1164 // 1165 // 1) input or 2) input or 3) input __ 1166 // / \ / \ \ / \ 1167 // \ / | cast phi cast 1168 // phi \ / / \ / 1169 // phi / -- 1170 1171 Node* r = in(0); // RegionNode 1172 if (r == NULL) return in(1); // Already degraded to a Copy 1173 Node* uncasted_input = NULL; // The unique uncasted input (ConstraintCasts removed) 1174 Node* direct_input = NULL; // The unique direct input 1175 1176 for (uint i = 1, cnt = req(); i < cnt; ++i) { 1177 Node* rc = r->in(i); 1178 if (rc == NULL || phase->type(rc) == Type::TOP) 1179 continue; // ignore unreachable control path 1180 Node* n = in(i); 1181 if (n == NULL) 1182 continue; 1183 Node* un = n->uncast(); 1184 if (un == NULL || un == this || phase->type(un) == Type::TOP) { 1185 continue; // ignore if top, or in(i) and "this" are in a data cycle 1186 } 1187 // Check for a unique uncasted input 1188 if (uncasted_input == NULL) { 1189 uncasted_input = un; 1190 } else if (uncasted_input != un) { 1191 uncasted_input = NodeSentinel; // no unique uncasted input 1192 } 1193 // Check for a unique direct input 1194 if (direct_input == NULL) { 1195 direct_input = n; 1196 } else if (direct_input != n) { 1197 direct_input = NodeSentinel; // no unique direct input 1198 } 1199 } 1200 if (direct_input == NULL) { 1201 return phase->C->top(); // no inputs 1202 } 1203 assert(uncasted_input != NULL,""); 1204 1205 if (direct_input != NodeSentinel) { 1206 return direct_input; // one unique direct input 1207 } 1208 if (uncasted_input != NodeSentinel && 1209 phase->type(uncasted_input)->higher_equal(type())) { 1210 return uncasted_input; // one unique uncasted input 1211 } 1212 1213 // Nothing. 1214 return NULL; 1215 } 1216 1217 //------------------------------is_x2logic------------------------------------- 1218 // Check for simple convert-to-boolean pattern 1219 // If:(C Bool) Region:(IfF IfT) Phi:(Region 0 1) 1220 // Convert Phi to an ConvIB. 1221 static Node *is_x2logic( PhaseGVN *phase, PhiNode *phi, int true_path ) { 1222 assert(true_path !=0, "only diamond shape graph expected"); 1223 // Convert the true/false index into an expected 0/1 return. 1224 // Map 2->0 and 1->1. 1225 int flipped = 2-true_path; 1226 1227 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1228 // phi->region->if_proj->ifnode->bool->cmp 1229 Node *region = phi->in(0); 1230 Node *iff = region->in(1)->in(0); 1231 BoolNode *b = (BoolNode*)iff->in(1); 1232 const CmpNode *cmp = (CmpNode*)b->in(1); 1233 1234 Node *zero = phi->in(1); 1235 Node *one = phi->in(2); 1236 const Type *tzero = phase->type( zero ); 1237 const Type *tone = phase->type( one ); 1238 1239 // Check for compare vs 0 1240 const Type *tcmp = phase->type(cmp->in(2)); 1241 if( tcmp != TypeInt::ZERO && tcmp != TypePtr::NULL_PTR ) { 1242 // Allow cmp-vs-1 if the other input is bounded by 0-1 1243 if( !(tcmp == TypeInt::ONE && phase->type(cmp->in(1)) == TypeInt::BOOL) ) 1244 return NULL; 1245 flipped = 1-flipped; // Test is vs 1 instead of 0! 1246 } 1247 1248 // Check for setting zero/one opposite expected 1249 if( tzero == TypeInt::ZERO ) { 1250 if( tone == TypeInt::ONE ) { 1251 } else return NULL; 1252 } else if( tzero == TypeInt::ONE ) { 1253 if( tone == TypeInt::ZERO ) { 1254 flipped = 1-flipped; 1255 } else return NULL; 1256 } else return NULL; 1257 1258 // Check for boolean test backwards 1259 if( b->_test._test == BoolTest::ne ) { 1260 } else if( b->_test._test == BoolTest::eq ) { 1261 flipped = 1-flipped; 1262 } else return NULL; 1263 1264 // Build int->bool conversion 1265 Node *n = new Conv2BNode( cmp->in(1) ); 1266 if( flipped ) 1267 n = new XorINode( phase->transform(n), phase->intcon(1) ); 1268 1269 return n; 1270 } 1271 1272 //------------------------------is_cond_add------------------------------------ 1273 // Check for simple conditional add pattern: "(P < Q) ? X+Y : X;" 1274 // To be profitable the control flow has to disappear; there can be no other 1275 // values merging here. We replace the test-and-branch with: 1276 // "(sgn(P-Q))&Y) + X". Basically, convert "(P < Q)" into 0 or -1 by 1277 // moving the carry bit from (P-Q) into a register with 'sbb EAX,EAX'. 1278 // Then convert Y to 0-or-Y and finally add. 1279 // This is a key transform for SpecJava _201_compress. 1280 static Node* is_cond_add(PhaseGVN *phase, PhiNode *phi, int true_path) { 1281 assert(true_path !=0, "only diamond shape graph expected"); 1282 1283 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1284 // phi->region->if_proj->ifnode->bool->cmp 1285 RegionNode *region = (RegionNode*)phi->in(0); 1286 Node *iff = region->in(1)->in(0); 1287 BoolNode* b = iff->in(1)->as_Bool(); 1288 const CmpNode *cmp = (CmpNode*)b->in(1); 1289 1290 // Make sure only merging this one phi here 1291 if (region->has_unique_phi() != phi) return NULL; 1292 1293 // Make sure each arm of the diamond has exactly one output, which we assume 1294 // is the region. Otherwise, the control flow won't disappear. 1295 if (region->in(1)->outcnt() != 1) return NULL; 1296 if (region->in(2)->outcnt() != 1) return NULL; 1297 1298 // Check for "(P < Q)" of type signed int 1299 if (b->_test._test != BoolTest::lt) return NULL; 1300 if (cmp->Opcode() != Op_CmpI) return NULL; 1301 1302 Node *p = cmp->in(1); 1303 Node *q = cmp->in(2); 1304 Node *n1 = phi->in( true_path); 1305 Node *n2 = phi->in(3-true_path); 1306 1307 int op = n1->Opcode(); 1308 if( op != Op_AddI // Need zero as additive identity 1309 /*&&op != Op_SubI && 1310 op != Op_AddP && 1311 op != Op_XorI && 1312 op != Op_OrI*/ ) 1313 return NULL; 1314 1315 Node *x = n2; 1316 Node *y = NULL; 1317 if( x == n1->in(1) ) { 1318 y = n1->in(2); 1319 } else if( x == n1->in(2) ) { 1320 y = n1->in(1); 1321 } else return NULL; 1322 1323 // Not so profitable if compare and add are constants 1324 if( q->is_Con() && phase->type(q) != TypeInt::ZERO && y->is_Con() ) 1325 return NULL; 1326 1327 Node *cmplt = phase->transform( new CmpLTMaskNode(p,q) ); 1328 Node *j_and = phase->transform( new AndINode(cmplt,y) ); 1329 return new AddINode(j_and,x); 1330 } 1331 1332 //------------------------------is_absolute------------------------------------ 1333 // Check for absolute value. 1334 static Node* is_absolute( PhaseGVN *phase, PhiNode *phi_root, int true_path) { 1335 assert(true_path !=0, "only diamond shape graph expected"); 1336 1337 int cmp_zero_idx = 0; // Index of compare input where to look for zero 1338 int phi_x_idx = 0; // Index of phi input where to find naked x 1339 1340 // ABS ends with the merge of 2 control flow paths. 1341 // Find the false path from the true path. With only 2 inputs, 3 - x works nicely. 1342 int false_path = 3 - true_path; 1343 1344 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: 1345 // phi->region->if_proj->ifnode->bool->cmp 1346 BoolNode *bol = phi_root->in(0)->in(1)->in(0)->in(1)->as_Bool(); 1347 1348 // Check bool sense 1349 switch( bol->_test._test ) { 1350 case BoolTest::lt: cmp_zero_idx = 1; phi_x_idx = true_path; break; 1351 case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break; 1352 case BoolTest::gt: cmp_zero_idx = 2; phi_x_idx = true_path; break; 1353 case BoolTest::ge: cmp_zero_idx = 1; phi_x_idx = false_path; break; 1354 default: return NULL; break; 1355 } 1356 1357 // Test is next 1358 Node *cmp = bol->in(1); 1359 const Type *tzero = NULL; 1360 switch( cmp->Opcode() ) { 1361 case Op_CmpF: tzero = TypeF::ZERO; break; // Float ABS 1362 case Op_CmpD: tzero = TypeD::ZERO; break; // Double ABS 1363 default: return NULL; 1364 } 1365 1366 // Find zero input of compare; the other input is being abs'd 1367 Node *x = NULL; 1368 bool flip = false; 1369 if( phase->type(cmp->in(cmp_zero_idx)) == tzero ) { 1370 x = cmp->in(3 - cmp_zero_idx); 1371 } else if( phase->type(cmp->in(3 - cmp_zero_idx)) == tzero ) { 1372 // The test is inverted, we should invert the result... 1373 x = cmp->in(cmp_zero_idx); 1374 flip = true; 1375 } else { 1376 return NULL; 1377 } 1378 1379 // Next get the 2 pieces being selected, one is the original value 1380 // and the other is the negated value. 1381 if( phi_root->in(phi_x_idx) != x ) return NULL; 1382 1383 // Check other phi input for subtract node 1384 Node *sub = phi_root->in(3 - phi_x_idx); 1385 1386 // Allow only Sub(0,X) and fail out for all others; Neg is not OK 1387 if( tzero == TypeF::ZERO ) { 1388 if( sub->Opcode() != Op_SubF || 1389 sub->in(2) != x || 1390 phase->type(sub->in(1)) != tzero ) return NULL; 1391 x = new AbsFNode(x); 1392 if (flip) { 1393 x = new SubFNode(sub->in(1), phase->transform(x)); 1394 } 1395 } else { 1396 if( sub->Opcode() != Op_SubD || 1397 sub->in(2) != x || 1398 phase->type(sub->in(1)) != tzero ) return NULL; 1399 x = new AbsDNode(x); 1400 if (flip) { 1401 x = new SubDNode(sub->in(1), phase->transform(x)); 1402 } 1403 } 1404 1405 return x; 1406 } 1407 1408 //------------------------------split_once------------------------------------- 1409 // Helper for split_flow_path 1410 static void split_once(PhaseIterGVN *igvn, Node *phi, Node *val, Node *n, Node *newn) { 1411 igvn->hash_delete(n); // Remove from hash before hacking edges 1412 1413 uint j = 1; 1414 for (uint i = phi->req()-1; i > 0; i--) { 1415 if (phi->in(i) == val) { // Found a path with val? 1416 // Add to NEW Region/Phi, no DU info 1417 newn->set_req( j++, n->in(i) ); 1418 // Remove from OLD Region/Phi 1419 n->del_req(i); 1420 } 1421 } 1422 1423 // Register the new node but do not transform it. Cannot transform until the 1424 // entire Region/Phi conglomerate has been hacked as a single huge transform. 1425 igvn->register_new_node_with_optimizer( newn ); 1426 1427 // Now I can point to the new node. 1428 n->add_req(newn); 1429 igvn->_worklist.push(n); 1430 } 1431 1432 //------------------------------split_flow_path-------------------------------- 1433 // Check for merging identical values and split flow paths 1434 static Node* split_flow_path(PhaseGVN *phase, PhiNode *phi) { 1435 BasicType bt = phi->type()->basic_type(); 1436 if( bt == T_ILLEGAL || type2size[bt] <= 0 ) 1437 return NULL; // Bail out on funny non-value stuff 1438 if( phi->req() <= 3 ) // Need at least 2 matched inputs and a 1439 return NULL; // third unequal input to be worth doing 1440 1441 // Scan for a constant 1442 uint i; 1443 for( i = 1; i < phi->req()-1; i++ ) { 1444 Node *n = phi->in(i); 1445 if( !n ) return NULL; 1446 if( phase->type(n) == Type::TOP ) return NULL; 1447 if( n->Opcode() == Op_ConP || n->Opcode() == Op_ConN || n->Opcode() == Op_ConNKlass ) 1448 break; 1449 } 1450 if( i >= phi->req() ) // Only split for constants 1451 return NULL; 1452 1453 Node *val = phi->in(i); // Constant to split for 1454 uint hit = 0; // Number of times it occurs 1455 Node *r = phi->region(); 1456 1457 for( ; i < phi->req(); i++ ){ // Count occurrences of constant 1458 Node *n = phi->in(i); 1459 if( !n ) return NULL; 1460 if( phase->type(n) == Type::TOP ) return NULL; 1461 if( phi->in(i) == val ) { 1462 hit++; 1463 if (PhaseIdealLoop::find_predicate(r->in(i)) != NULL) { 1464 return NULL; // don't split loop entry path 1465 } 1466 } 1467 } 1468 1469 if( hit <= 1 || // Make sure we find 2 or more 1470 hit == phi->req()-1 ) // and not ALL the same value 1471 return NULL; 1472 1473 // Now start splitting out the flow paths that merge the same value. 1474 // Split first the RegionNode. 1475 PhaseIterGVN *igvn = phase->is_IterGVN(); 1476 RegionNode *newr = new RegionNode(hit+1); 1477 split_once(igvn, phi, val, r, newr); 1478 1479 // Now split all other Phis than this one 1480 for (DUIterator_Fast kmax, k = r->fast_outs(kmax); k < kmax; k++) { 1481 Node* phi2 = r->fast_out(k); 1482 if( phi2->is_Phi() && phi2->as_Phi() != phi ) { 1483 PhiNode *newphi = PhiNode::make_blank(newr, phi2); 1484 split_once(igvn, phi, val, phi2, newphi); 1485 } 1486 } 1487 1488 // Clean up this guy 1489 igvn->hash_delete(phi); 1490 for( i = phi->req()-1; i > 0; i-- ) { 1491 if( phi->in(i) == val ) { 1492 phi->del_req(i); 1493 } 1494 } 1495 phi->add_req(val); 1496 1497 return phi; 1498 } 1499 1500 //============================================================================= 1501 //------------------------------simple_data_loop_check------------------------- 1502 // Try to determining if the phi node in a simple safe/unsafe data loop. 1503 // Returns: 1504 // enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop }; 1505 // Safe - safe case when the phi and it's inputs reference only safe data 1506 // nodes; 1507 // Unsafe - the phi and it's inputs reference unsafe data nodes but there 1508 // is no reference back to the phi - need a graph walk 1509 // to determine if it is in a loop; 1510 // UnsafeLoop - unsafe case when the phi references itself directly or through 1511 // unsafe data node. 1512 // Note: a safe data node is a node which could/never reference itself during 1513 // GVN transformations. For now it is Con, Proj, Phi, CastPP, CheckCastPP. 1514 // I mark Phi nodes as safe node not only because they can reference itself 1515 // but also to prevent mistaking the fallthrough case inside an outer loop 1516 // as dead loop when the phi references itselfs through an other phi. 1517 PhiNode::LoopSafety PhiNode::simple_data_loop_check(Node *in) const { 1518 // It is unsafe loop if the phi node references itself directly. 1519 if (in == (Node*)this) 1520 return UnsafeLoop; // Unsafe loop 1521 // Unsafe loop if the phi node references itself through an unsafe data node. 1522 // Exclude cases with null inputs or data nodes which could reference 1523 // itself (safe for dead loops). 1524 if (in != NULL && !in->is_dead_loop_safe()) { 1525 // Check inputs of phi's inputs also. 1526 // It is much less expensive then full graph walk. 1527 uint cnt = in->req(); 1528 uint i = (in->is_Proj() && !in->is_CFG()) ? 0 : 1; 1529 for (; i < cnt; ++i) { 1530 Node* m = in->in(i); 1531 if (m == (Node*)this) 1532 return UnsafeLoop; // Unsafe loop 1533 if (m != NULL && !m->is_dead_loop_safe()) { 1534 // Check the most common case (about 30% of all cases): 1535 // phi->Load/Store->AddP->(ConP ConP Con)/(Parm Parm Con). 1536 Node *m1 = (m->is_AddP() && m->req() > 3) ? m->in(1) : NULL; 1537 if (m1 == (Node*)this) 1538 return UnsafeLoop; // Unsafe loop 1539 if (m1 != NULL && m1 == m->in(2) && 1540 m1->is_dead_loop_safe() && m->in(3)->is_Con()) { 1541 continue; // Safe case 1542 } 1543 // The phi references an unsafe node - need full analysis. 1544 return Unsafe; 1545 } 1546 } 1547 } 1548 return Safe; // Safe case - we can optimize the phi node. 1549 } 1550 1551 //------------------------------is_unsafe_data_reference----------------------- 1552 // If phi can be reached through the data input - it is data loop. 1553 bool PhiNode::is_unsafe_data_reference(Node *in) const { 1554 assert(req() > 1, ""); 1555 // First, check simple cases when phi references itself directly or 1556 // through an other node. 1557 LoopSafety safety = simple_data_loop_check(in); 1558 if (safety == UnsafeLoop) 1559 return true; // phi references itself - unsafe loop 1560 else if (safety == Safe) 1561 return false; // Safe case - phi could be replaced with the unique input. 1562 1563 // Unsafe case when we should go through data graph to determine 1564 // if the phi references itself. 1565 1566 ResourceMark rm; 1567 1568 Arena *a = Thread::current()->resource_area(); 1569 Node_List nstack(a); 1570 VectorSet visited(a); 1571 1572 nstack.push(in); // Start with unique input. 1573 visited.set(in->_idx); 1574 while (nstack.size() != 0) { 1575 Node* n = nstack.pop(); 1576 uint cnt = n->req(); 1577 uint i = (n->is_Proj() && !n->is_CFG()) ? 0 : 1; 1578 for (; i < cnt; i++) { 1579 Node* m = n->in(i); 1580 if (m == (Node*)this) { 1581 return true; // Data loop 1582 } 1583 if (m != NULL && !m->is_dead_loop_safe()) { // Only look for unsafe cases. 1584 if (!visited.test_set(m->_idx)) 1585 nstack.push(m); 1586 } 1587 } 1588 } 1589 return false; // The phi is not reachable from its inputs 1590 } 1591 1592 1593 //------------------------------Ideal------------------------------------------ 1594 // Return a node which is more "ideal" than the current node. Must preserve 1595 // the CFG, but we can still strip out dead paths. 1596 Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1597 // The next should never happen after 6297035 fix. 1598 if( is_copy() ) // Already degraded to a Copy ? 1599 return NULL; // No change 1600 1601 Node *r = in(0); // RegionNode 1602 assert(r->in(0) == NULL || !r->in(0)->is_Root(), "not a specially hidden merge"); 1603 1604 // Note: During parsing, phis are often transformed before their regions. 1605 // This means we have to use type_or_null to defend against untyped regions. 1606 if( phase->type_or_null(r) == Type::TOP ) // Dead code? 1607 return NULL; // No change 1608 1609 Node *top = phase->C->top(); 1610 bool new_phi = (outcnt() == 0); // transforming new Phi 1611 // No change for igvn if new phi is not hooked 1612 if (new_phi && can_reshape) 1613 return NULL; 1614 1615 // The are 2 situations when only one valid phi's input is left 1616 // (in addition to Region input). 1617 // One: region is not loop - replace phi with this input. 1618 // Two: region is loop - replace phi with top since this data path is dead 1619 // and we need to break the dead data loop. 1620 Node* progress = NULL; // Record if any progress made 1621 for( uint j = 1; j < req(); ++j ){ // For all paths in 1622 // Check unreachable control paths 1623 Node* rc = r->in(j); 1624 Node* n = in(j); // Get the input 1625 if (rc == NULL || phase->type(rc) == Type::TOP) { 1626 if (n != top) { // Not already top? 1627 PhaseIterGVN *igvn = phase->is_IterGVN(); 1628 if (can_reshape && igvn != NULL) { 1629 igvn->_worklist.push(r); 1630 } 1631 set_req(j, top); // Nuke it down 1632 progress = this; // Record progress 1633 } 1634 } 1635 } 1636 1637 if (can_reshape && outcnt() == 0) { 1638 // set_req() above may kill outputs if Phi is referenced 1639 // only by itself on the dead (top) control path. 1640 return top; 1641 } 1642 1643 Node* uin = unique_input(phase); 1644 if (uin == top) { // Simplest case: no alive inputs. 1645 if (can_reshape) // IGVN transformation 1646 return top; 1647 else 1648 return NULL; // Identity will return TOP 1649 } else if (uin != NULL) { 1650 // Only one not-NULL unique input path is left. 1651 // Determine if this input is backedge of a loop. 1652 // (Skip new phis which have no uses and dead regions). 1653 if (outcnt() > 0 && r->in(0) != NULL) { 1654 // First, take the short cut when we know it is a loop and 1655 // the EntryControl data path is dead. 1656 // Loop node may have only one input because entry path 1657 // is removed in PhaseIdealLoop::Dominators(). 1658 assert(!r->is_Loop() || r->req() <= 3, "Loop node should have 3 or less inputs"); 1659 bool is_loop = (r->is_Loop() && r->req() == 3); 1660 // Then, check if there is a data loop when phi references itself directly 1661 // or through other data nodes. 1662 if (is_loop && !uin->eqv_uncast(in(LoopNode::EntryControl)) || 1663 !is_loop && is_unsafe_data_reference(uin)) { 1664 // Break this data loop to avoid creation of a dead loop. 1665 if (can_reshape) { 1666 return top; 1667 } else { 1668 // We can't return top if we are in Parse phase - cut inputs only 1669 // let Identity to handle the case. 1670 replace_edge(uin, top); 1671 return NULL; 1672 } 1673 } 1674 } 1675 1676 // One unique input. 1677 debug_only(Node* ident = Identity(phase)); 1678 // The unique input must eventually be detected by the Identity call. 1679 #ifdef ASSERT 1680 if (ident != uin && !ident->is_top()) { 1681 // print this output before failing assert 1682 r->dump(3); 1683 this->dump(3); 1684 ident->dump(); 1685 uin->dump(); 1686 } 1687 #endif 1688 assert(ident == uin || ident->is_top(), "Identity must clean this up"); 1689 return NULL; 1690 } 1691 1692 1693 Node* opt = NULL; 1694 int true_path = is_diamond_phi(); 1695 if( true_path != 0 ) { 1696 // Check for CMove'ing identity. If it would be unsafe, 1697 // handle it here. In the safe case, let Identity handle it. 1698 Node* unsafe_id = is_cmove_id(phase, true_path); 1699 if( unsafe_id != NULL && is_unsafe_data_reference(unsafe_id) ) 1700 opt = unsafe_id; 1701 1702 // Check for simple convert-to-boolean pattern 1703 if( opt == NULL ) 1704 opt = is_x2logic(phase, this, true_path); 1705 1706 // Check for absolute value 1707 if( opt == NULL ) 1708 opt = is_absolute(phase, this, true_path); 1709 1710 // Check for conditional add 1711 if( opt == NULL && can_reshape ) 1712 opt = is_cond_add(phase, this, true_path); 1713 1714 // These 4 optimizations could subsume the phi: 1715 // have to check for a dead data loop creation. 1716 if( opt != NULL ) { 1717 if( opt == unsafe_id || is_unsafe_data_reference(opt) ) { 1718 // Found dead loop. 1719 if( can_reshape ) 1720 return top; 1721 // We can't return top if we are in Parse phase - cut inputs only 1722 // to stop further optimizations for this phi. Identity will return TOP. 1723 assert(req() == 3, "only diamond merge phi here"); 1724 set_req(1, top); 1725 set_req(2, top); 1726 return NULL; 1727 } else { 1728 return opt; 1729 } 1730 } 1731 } 1732 1733 // Check for merging identical values and split flow paths 1734 if (can_reshape) { 1735 opt = split_flow_path(phase, this); 1736 // This optimization only modifies phi - don't need to check for dead loop. 1737 assert(opt == NULL || phase->eqv(opt, this), "do not elide phi"); 1738 if (opt != NULL) return opt; 1739 } 1740 1741 if (in(1) != NULL && in(1)->Opcode() == Op_AddP && can_reshape) { 1742 // Try to undo Phi of AddP: 1743 // (Phi (AddP base base y) (AddP base2 base2 y)) 1744 // becomes: 1745 // newbase := (Phi base base2) 1746 // (AddP newbase newbase y) 1747 // 1748 // This occurs as a result of unsuccessful split_thru_phi and 1749 // interferes with taking advantage of addressing modes. See the 1750 // clone_shift_expressions code in matcher.cpp 1751 Node* addp = in(1); 1752 const Type* type = addp->in(AddPNode::Base)->bottom_type(); 1753 Node* y = addp->in(AddPNode::Offset); 1754 if (y != NULL && addp->in(AddPNode::Base) == addp->in(AddPNode::Address)) { 1755 // make sure that all the inputs are similar to the first one, 1756 // i.e. AddP with base == address and same offset as first AddP 1757 bool doit = true; 1758 for (uint i = 2; i < req(); i++) { 1759 if (in(i) == NULL || 1760 in(i)->Opcode() != Op_AddP || 1761 in(i)->in(AddPNode::Base) != in(i)->in(AddPNode::Address) || 1762 in(i)->in(AddPNode::Offset) != y) { 1763 doit = false; 1764 break; 1765 } 1766 // Accumulate type for resulting Phi 1767 type = type->meet_speculative(in(i)->in(AddPNode::Base)->bottom_type()); 1768 } 1769 Node* base = NULL; 1770 if (doit) { 1771 // Check for neighboring AddP nodes in a tree. 1772 // If they have a base, use that it. 1773 for (DUIterator_Fast kmax, k = this->fast_outs(kmax); k < kmax; k++) { 1774 Node* u = this->fast_out(k); 1775 if (u->is_AddP()) { 1776 Node* base2 = u->in(AddPNode::Base); 1777 if (base2 != NULL && !base2->is_top()) { 1778 if (base == NULL) 1779 base = base2; 1780 else if (base != base2) 1781 { doit = false; break; } 1782 } 1783 } 1784 } 1785 } 1786 if (doit) { 1787 if (base == NULL) { 1788 base = new PhiNode(in(0), type, NULL); 1789 for (uint i = 1; i < req(); i++) { 1790 base->init_req(i, in(i)->in(AddPNode::Base)); 1791 } 1792 phase->is_IterGVN()->register_new_node_with_optimizer(base); 1793 } 1794 return new AddPNode(base, base, y); 1795 } 1796 } 1797 } 1798 1799 // Split phis through memory merges, so that the memory merges will go away. 1800 // Piggy-back this transformation on the search for a unique input.... 1801 // It will be as if the merged memory is the unique value of the phi. 1802 // (Do not attempt this optimization unless parsing is complete. 1803 // It would make the parser's memory-merge logic sick.) 1804 // (MergeMemNode is not dead_loop_safe - need to check for dead loop.) 1805 if (progress == NULL && can_reshape && type() == Type::MEMORY) { 1806 // see if this phi should be sliced 1807 uint merge_width = 0; 1808 bool saw_self = false; 1809 for( uint i=1; i<req(); ++i ) {// For all paths in 1810 Node *ii = in(i); 1811 if (ii->is_MergeMem()) { 1812 MergeMemNode* n = ii->as_MergeMem(); 1813 merge_width = MAX2(merge_width, n->req()); 1814 saw_self = saw_self || phase->eqv(n->base_memory(), this); 1815 } 1816 } 1817 1818 // This restriction is temporarily necessary to ensure termination: 1819 if (!saw_self && adr_type() == TypePtr::BOTTOM) merge_width = 0; 1820 1821 if (merge_width > Compile::AliasIdxRaw) { 1822 // found at least one non-empty MergeMem 1823 const TypePtr* at = adr_type(); 1824 if (at != TypePtr::BOTTOM) { 1825 // Patch the existing phi to select an input from the merge: 1826 // Phi:AT1(...MergeMem(m0, m1, m2)...) into 1827 // Phi:AT1(...m1...) 1828 int alias_idx = phase->C->get_alias_index(at); 1829 for (uint i=1; i<req(); ++i) { 1830 Node *ii = in(i); 1831 if (ii->is_MergeMem()) { 1832 MergeMemNode* n = ii->as_MergeMem(); 1833 // compress paths and change unreachable cycles to TOP 1834 // If not, we can update the input infinitely along a MergeMem cycle 1835 // Equivalent code is in MemNode::Ideal_common 1836 Node *m = phase->transform(n); 1837 if (outcnt() == 0) { // Above transform() may kill us! 1838 return top; 1839 } 1840 // If transformed to a MergeMem, get the desired slice 1841 // Otherwise the returned node represents memory for every slice 1842 Node *new_mem = (m->is_MergeMem()) ? 1843 m->as_MergeMem()->memory_at(alias_idx) : m; 1844 // Update input if it is progress over what we have now 1845 if (new_mem != ii) { 1846 set_req(i, new_mem); 1847 progress = this; 1848 } 1849 } 1850 } 1851 } else { 1852 // We know that at least one MergeMem->base_memory() == this 1853 // (saw_self == true). If all other inputs also references this phi 1854 // (directly or through data nodes) - it is dead loop. 1855 bool saw_safe_input = false; 1856 for (uint j = 1; j < req(); ++j) { 1857 Node *n = in(j); 1858 if (n->is_MergeMem() && n->as_MergeMem()->base_memory() == this) 1859 continue; // skip known cases 1860 if (!is_unsafe_data_reference(n)) { 1861 saw_safe_input = true; // found safe input 1862 break; 1863 } 1864 } 1865 if (!saw_safe_input) 1866 return top; // all inputs reference back to this phi - dead loop 1867 1868 // Phi(...MergeMem(m0, m1:AT1, m2:AT2)...) into 1869 // MergeMem(Phi(...m0...), Phi:AT1(...m1...), Phi:AT2(...m2...)) 1870 PhaseIterGVN *igvn = phase->is_IterGVN(); 1871 Node* hook = new Node(1); 1872 PhiNode* new_base = (PhiNode*) clone(); 1873 // Must eagerly register phis, since they participate in loops. 1874 if (igvn) { 1875 igvn->register_new_node_with_optimizer(new_base); 1876 hook->add_req(new_base); 1877 } 1878 MergeMemNode* result = MergeMemNode::make(new_base); 1879 for (uint i = 1; i < req(); ++i) { 1880 Node *ii = in(i); 1881 if (ii->is_MergeMem()) { 1882 MergeMemNode* n = ii->as_MergeMem(); 1883 for (MergeMemStream mms(result, n); mms.next_non_empty2(); ) { 1884 // If we have not seen this slice yet, make a phi for it. 1885 bool made_new_phi = false; 1886 if (mms.is_empty()) { 1887 Node* new_phi = new_base->slice_memory(mms.adr_type(phase->C)); 1888 made_new_phi = true; 1889 if (igvn) { 1890 igvn->register_new_node_with_optimizer(new_phi); 1891 hook->add_req(new_phi); 1892 } 1893 mms.set_memory(new_phi); 1894 } 1895 Node* phi = mms.memory(); 1896 assert(made_new_phi || phi->in(i) == n, "replace the i-th merge by a slice"); 1897 phi->set_req(i, mms.memory2()); 1898 } 1899 } 1900 } 1901 // Distribute all self-loops. 1902 { // (Extra braces to hide mms.) 1903 for (MergeMemStream mms(result); mms.next_non_empty(); ) { 1904 Node* phi = mms.memory(); 1905 for (uint i = 1; i < req(); ++i) { 1906 if (phi->in(i) == this) phi->set_req(i, phi); 1907 } 1908 } 1909 } 1910 // now transform the new nodes, and return the mergemem 1911 for (MergeMemStream mms(result); mms.next_non_empty(); ) { 1912 Node* phi = mms.memory(); 1913 mms.set_memory(phase->transform(phi)); 1914 } 1915 if (igvn) { // Unhook. 1916 igvn->hash_delete(hook); 1917 for (uint i = 1; i < hook->req(); i++) { 1918 hook->set_req(i, NULL); 1919 } 1920 } 1921 // Replace self with the result. 1922 return result; 1923 } 1924 } 1925 // 1926 // Other optimizations on the memory chain 1927 // 1928 const TypePtr* at = adr_type(); 1929 for( uint i=1; i<req(); ++i ) {// For all paths in 1930 Node *ii = in(i); 1931 Node *new_in = MemNode::optimize_memory_chain(ii, at, NULL, phase); 1932 if (ii != new_in ) { 1933 set_req(i, new_in); 1934 progress = this; 1935 } 1936 } 1937 } 1938 1939 #ifdef _LP64 1940 // Push DecodeN/DecodeNKlass down through phi. 1941 // The rest of phi graph will transform by split EncodeP node though phis up. 1942 if ((UseCompressedOops || UseCompressedClassPointers) && can_reshape && progress == NULL) { 1943 bool may_push = true; 1944 bool has_decodeN = false; 1945 bool is_decodeN = false; 1946 for (uint i=1; i<req(); ++i) {// For all paths in 1947 Node *ii = in(i); 1948 if (ii->is_DecodeNarrowPtr() && ii->bottom_type() == bottom_type()) { 1949 // Do optimization if a non dead path exist. 1950 if (ii->in(1)->bottom_type() != Type::TOP) { 1951 has_decodeN = true; 1952 is_decodeN = ii->is_DecodeN(); 1953 } 1954 } else if (!ii->is_Phi()) { 1955 may_push = false; 1956 } 1957 } 1958 1959 if (has_decodeN && may_push) { 1960 PhaseIterGVN *igvn = phase->is_IterGVN(); 1961 // Make narrow type for new phi. 1962 const Type* narrow_t; 1963 if (is_decodeN) { 1964 narrow_t = TypeNarrowOop::make(this->bottom_type()->is_ptr()); 1965 } else { 1966 narrow_t = TypeNarrowKlass::make(this->bottom_type()->is_ptr()); 1967 } 1968 PhiNode* new_phi = new PhiNode(r, narrow_t); 1969 uint orig_cnt = req(); 1970 for (uint i=1; i<req(); ++i) {// For all paths in 1971 Node *ii = in(i); 1972 Node* new_ii = NULL; 1973 if (ii->is_DecodeNarrowPtr()) { 1974 assert(ii->bottom_type() == bottom_type(), "sanity"); 1975 new_ii = ii->in(1); 1976 } else { 1977 assert(ii->is_Phi(), "sanity"); 1978 if (ii->as_Phi() == this) { 1979 new_ii = new_phi; 1980 } else { 1981 if (is_decodeN) { 1982 new_ii = new EncodePNode(ii, narrow_t); 1983 } else { 1984 new_ii = new EncodePKlassNode(ii, narrow_t); 1985 } 1986 igvn->register_new_node_with_optimizer(new_ii); 1987 } 1988 } 1989 new_phi->set_req(i, new_ii); 1990 } 1991 igvn->register_new_node_with_optimizer(new_phi, this); 1992 if (is_decodeN) { 1993 progress = new DecodeNNode(new_phi, bottom_type()); 1994 } else { 1995 progress = new DecodeNKlassNode(new_phi, bottom_type()); 1996 } 1997 } 1998 } 1999 #endif 2000 2001 return progress; // Return any progress 2002 } 2003 2004 //------------------------------is_tripcount----------------------------------- 2005 bool PhiNode::is_tripcount() const { 2006 return (in(0) != NULL && in(0)->is_CountedLoop() && 2007 in(0)->as_CountedLoop()->phi() == this); 2008 } 2009 2010 //------------------------------out_RegMask------------------------------------ 2011 const RegMask &PhiNode::in_RegMask(uint i) const { 2012 return i ? out_RegMask() : RegMask::Empty; 2013 } 2014 2015 const RegMask &PhiNode::out_RegMask() const { 2016 uint ideal_reg = _type->ideal_reg(); 2017 assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" ); 2018 if( ideal_reg == 0 ) return RegMask::Empty; 2019 return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]); 2020 } 2021 2022 #ifndef PRODUCT 2023 void PhiNode::dump_spec(outputStream *st) const { 2024 TypeNode::dump_spec(st); 2025 if (is_tripcount()) { 2026 st->print(" #tripcount"); 2027 } 2028 } 2029 #endif 2030 2031 2032 //============================================================================= 2033 const Type *GotoNode::Value( PhaseTransform *phase ) const { 2034 // If the input is reachable, then we are executed. 2035 // If the input is not reachable, then we are not executed. 2036 return phase->type(in(0)); 2037 } 2038 2039 Node *GotoNode::Identity( PhaseTransform *phase ) { 2040 return in(0); // Simple copy of incoming control 2041 } 2042 2043 const RegMask &GotoNode::out_RegMask() const { 2044 return RegMask::Empty; 2045 } 2046 2047 //============================================================================= 2048 const RegMask &JumpNode::out_RegMask() const { 2049 return RegMask::Empty; 2050 } 2051 2052 //============================================================================= 2053 const RegMask &JProjNode::out_RegMask() const { 2054 return RegMask::Empty; 2055 } 2056 2057 //============================================================================= 2058 const RegMask &CProjNode::out_RegMask() const { 2059 return RegMask::Empty; 2060 } 2061 2062 2063 2064 //============================================================================= 2065 2066 uint PCTableNode::hash() const { return Node::hash() + _size; } 2067 uint PCTableNode::cmp( const Node &n ) const 2068 { return _size == ((PCTableNode&)n)._size; } 2069 2070 const Type *PCTableNode::bottom_type() const { 2071 const Type** f = TypeTuple::fields(_size); 2072 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; 2073 return TypeTuple::make(_size, f); 2074 } 2075 2076 //------------------------------Value------------------------------------------ 2077 // Compute the type of the PCTableNode. If reachable it is a tuple of 2078 // Control, otherwise the table targets are not reachable 2079 const Type *PCTableNode::Value( PhaseTransform *phase ) const { 2080 if( phase->type(in(0)) == Type::CONTROL ) 2081 return bottom_type(); 2082 return Type::TOP; // All paths dead? Then so are we 2083 } 2084 2085 //------------------------------Ideal------------------------------------------ 2086 // Return a node which is more "ideal" than the current node. Strip out 2087 // control copies 2088 Node *PCTableNode::Ideal(PhaseGVN *phase, bool can_reshape) { 2089 return remove_dead_region(phase, can_reshape) ? this : NULL; 2090 } 2091 2092 //============================================================================= 2093 uint JumpProjNode::hash() const { 2094 return Node::hash() + _dest_bci; 2095 } 2096 2097 uint JumpProjNode::cmp( const Node &n ) const { 2098 return ProjNode::cmp(n) && 2099 _dest_bci == ((JumpProjNode&)n)._dest_bci; 2100 } 2101 2102 #ifndef PRODUCT 2103 void JumpProjNode::dump_spec(outputStream *st) const { 2104 ProjNode::dump_spec(st); 2105 st->print("@bci %d ",_dest_bci); 2106 } 2107 #endif 2108 2109 //============================================================================= 2110 //------------------------------Value------------------------------------------ 2111 // Check for being unreachable, or for coming from a Rethrow. Rethrow's cannot 2112 // have the default "fall_through_index" path. 2113 const Type *CatchNode::Value( PhaseTransform *phase ) const { 2114 // Unreachable? Then so are all paths from here. 2115 if( phase->type(in(0)) == Type::TOP ) return Type::TOP; 2116 // First assume all paths are reachable 2117 const Type** f = TypeTuple::fields(_size); 2118 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; 2119 // Identify cases that will always throw an exception 2120 // () rethrow call 2121 // () virtual or interface call with NULL receiver 2122 // () call is a check cast with incompatible arguments 2123 if( in(1)->is_Proj() ) { 2124 Node *i10 = in(1)->in(0); 2125 if( i10->is_Call() ) { 2126 CallNode *call = i10->as_Call(); 2127 // Rethrows always throw exceptions, never return 2128 if (call->entry_point() == OptoRuntime::rethrow_stub()) { 2129 f[CatchProjNode::fall_through_index] = Type::TOP; 2130 } else if( call->req() > TypeFunc::Parms ) { 2131 const Type *arg0 = phase->type( call->in(TypeFunc::Parms) ); 2132 // Check for null receiver to virtual or interface calls 2133 if( call->is_CallDynamicJava() && 2134 arg0->higher_equal(TypePtr::NULL_PTR) ) { 2135 f[CatchProjNode::fall_through_index] = Type::TOP; 2136 } 2137 } // End of if not a runtime stub 2138 } // End of if have call above me 2139 } // End of slot 1 is not a projection 2140 return TypeTuple::make(_size, f); 2141 } 2142 2143 //============================================================================= 2144 uint CatchProjNode::hash() const { 2145 return Node::hash() + _handler_bci; 2146 } 2147 2148 2149 uint CatchProjNode::cmp( const Node &n ) const { 2150 return ProjNode::cmp(n) && 2151 _handler_bci == ((CatchProjNode&)n)._handler_bci; 2152 } 2153 2154 2155 //------------------------------Identity--------------------------------------- 2156 // If only 1 target is possible, choose it if it is the main control 2157 Node *CatchProjNode::Identity( PhaseTransform *phase ) { 2158 // If my value is control and no other value is, then treat as ID 2159 const TypeTuple *t = phase->type(in(0))->is_tuple(); 2160 if (t->field_at(_con) != Type::CONTROL) return this; 2161 // If we remove the last CatchProj and elide the Catch/CatchProj, then we 2162 // also remove any exception table entry. Thus we must know the call 2163 // feeding the Catch will not really throw an exception. This is ok for 2164 // the main fall-thru control (happens when we know a call can never throw 2165 // an exception) or for "rethrow", because a further optimization will 2166 // yank the rethrow (happens when we inline a function that can throw an 2167 // exception and the caller has no handler). Not legal, e.g., for passing 2168 // a NULL receiver to a v-call, or passing bad types to a slow-check-cast. 2169 // These cases MUST throw an exception via the runtime system, so the VM 2170 // will be looking for a table entry. 2171 Node *proj = in(0)->in(1); // Expect a proj feeding CatchNode 2172 CallNode *call; 2173 if (_con != TypeFunc::Control && // Bail out if not the main control. 2174 !(proj->is_Proj() && // AND NOT a rethrow 2175 proj->in(0)->is_Call() && 2176 (call = proj->in(0)->as_Call()) && 2177 call->entry_point() == OptoRuntime::rethrow_stub())) 2178 return this; 2179 2180 // Search for any other path being control 2181 for (uint i = 0; i < t->cnt(); i++) { 2182 if (i != _con && t->field_at(i) == Type::CONTROL) 2183 return this; 2184 } 2185 // Only my path is possible; I am identity on control to the jump 2186 return in(0)->in(0); 2187 } 2188 2189 2190 #ifndef PRODUCT 2191 void CatchProjNode::dump_spec(outputStream *st) const { 2192 ProjNode::dump_spec(st); 2193 st->print("@bci %d ",_handler_bci); 2194 } 2195 #endif 2196 2197 //============================================================================= 2198 //------------------------------Identity--------------------------------------- 2199 // Check for CreateEx being Identity. 2200 Node *CreateExNode::Identity( PhaseTransform *phase ) { 2201 if( phase->type(in(1)) == Type::TOP ) return in(1); 2202 if( phase->type(in(0)) == Type::TOP ) return in(0); 2203 // We only come from CatchProj, unless the CatchProj goes away. 2204 // If the CatchProj is optimized away, then we just carry the 2205 // exception oop through. 2206 CallNode *call = in(1)->in(0)->as_Call(); 2207 2208 return ( in(0)->is_CatchProj() && in(0)->in(0)->in(1) == in(1) ) 2209 ? this 2210 : call->in(TypeFunc::Parms); 2211 } 2212 2213 //============================================================================= 2214 //------------------------------Value------------------------------------------ 2215 // Check for being unreachable. 2216 const Type *NeverBranchNode::Value( PhaseTransform *phase ) const { 2217 if (!in(0) || in(0)->is_top()) return Type::TOP; 2218 return bottom_type(); 2219 } 2220 2221 //------------------------------Ideal------------------------------------------ 2222 // Check for no longer being part of a loop 2223 Node *NeverBranchNode::Ideal(PhaseGVN *phase, bool can_reshape) { 2224 if (can_reshape && !in(0)->is_Loop()) { 2225 // Dead code elimination can sometimes delete this projection so 2226 // if it's not there, there's nothing to do. 2227 Node* fallthru = proj_out(0); 2228 if (fallthru != NULL) { 2229 phase->is_IterGVN()->replace_node(fallthru, in(0)); 2230 } 2231 return phase->C->top(); 2232 } 2233 return NULL; 2234 } 2235 2236 #ifndef PRODUCT 2237 void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const { 2238 st->print("%s", Name()); 2239 } 2240 #endif