1 /* 2 * Copyright (c) 1998, 2011, 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 #ifndef SHARE_VM_OPTO_LOOPNODE_HPP 26 #define SHARE_VM_OPTO_LOOPNODE_HPP 27 28 #include "opto/cfgnode.hpp" 29 #include "opto/multnode.hpp" 30 #include "opto/phaseX.hpp" 31 #include "opto/subnode.hpp" 32 #include "opto/type.hpp" 33 34 class CmpNode; 35 class CountedLoopEndNode; 36 class CountedLoopNode; 37 class IdealLoopTree; 38 class LoopNode; 39 class Node; 40 class PhaseIdealLoop; 41 class VectorSet; 42 class Invariance; 43 struct small_cache; 44 45 // 46 // I D E A L I Z E D L O O P S 47 // 48 // Idealized loops are the set of loops I perform more interesting 49 // transformations on, beyond simple hoisting. 50 51 //------------------------------LoopNode--------------------------------------- 52 // Simple loop header. Fall in path on left, loop-back path on right. 53 class LoopNode : public RegionNode { 54 // Size is bigger to hold the flags. However, the flags do not change 55 // the semantics so it does not appear in the hash & cmp functions. 56 virtual uint size_of() const { return sizeof(*this); } 57 protected: 58 short _loop_flags; 59 // Names for flag bitfields 60 enum { Normal=0, Pre=1, Main=2, Post=3, PreMainPostFlagsMask=3, 61 MainHasNoPreLoop=4, 62 HasExactTripCount=8, 63 InnerLoop=16, 64 PartialPeelLoop=32, 65 PartialPeelFailed=64 }; 66 char _unswitch_count; 67 enum { _unswitch_max=3 }; 68 69 public: 70 // Names for edge indices 71 enum { Self=0, EntryControl, LoopBackControl }; 72 73 int is_inner_loop() const { return _loop_flags & InnerLoop; } 74 void set_inner_loop() { _loop_flags |= InnerLoop; } 75 76 int is_partial_peel_loop() const { return _loop_flags & PartialPeelLoop; } 77 void set_partial_peel_loop() { _loop_flags |= PartialPeelLoop; } 78 int partial_peel_has_failed() const { return _loop_flags & PartialPeelFailed; } 79 void mark_partial_peel_failed() { _loop_flags |= PartialPeelFailed; } 80 81 int unswitch_max() { return _unswitch_max; } 82 int unswitch_count() { return _unswitch_count; } 83 void set_unswitch_count(int val) { 84 assert (val <= unswitch_max(), "too many unswitches"); 85 _unswitch_count = val; 86 } 87 88 LoopNode( Node *entry, Node *backedge ) : RegionNode(3), _loop_flags(0), _unswitch_count(0) { 89 init_class_id(Class_Loop); 90 init_req(EntryControl, entry); 91 init_req(LoopBackControl, backedge); 92 } 93 94 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); 95 virtual int Opcode() const; 96 bool can_be_counted_loop(PhaseTransform* phase) const { 97 return req() == 3 && in(0) != NULL && 98 in(1) != NULL && phase->type(in(1)) != Type::TOP && 99 in(2) != NULL && phase->type(in(2)) != Type::TOP; 100 } 101 bool is_valid_counted_loop() const; 102 #ifndef PRODUCT 103 virtual void dump_spec(outputStream *st) const; 104 #endif 105 }; 106 107 //------------------------------Counted Loops---------------------------------- 108 // Counted loops are all trip-counted loops, with exactly 1 trip-counter exit 109 // path (and maybe some other exit paths). The trip-counter exit is always 110 // last in the loop. The trip-counter have to stride by a constant; 111 // the exit value is also loop invariant. 112 113 // CountedLoopNodes and CountedLoopEndNodes come in matched pairs. The 114 // CountedLoopNode has the incoming loop control and the loop-back-control 115 // which is always the IfTrue before the matching CountedLoopEndNode. The 116 // CountedLoopEndNode has an incoming control (possibly not the 117 // CountedLoopNode if there is control flow in the loop), the post-increment 118 // trip-counter value, and the limit. The trip-counter value is always of 119 // the form (Op old-trip-counter stride). The old-trip-counter is produced 120 // by a Phi connected to the CountedLoopNode. The stride is constant. 121 // The Op is any commutable opcode, including Add, Mul, Xor. The 122 // CountedLoopEndNode also takes in the loop-invariant limit value. 123 124 // From a CountedLoopNode I can reach the matching CountedLoopEndNode via the 125 // loop-back control. From CountedLoopEndNodes I can reach CountedLoopNodes 126 // via the old-trip-counter from the Op node. 127 128 //------------------------------CountedLoopNode-------------------------------- 129 // CountedLoopNodes head simple counted loops. CountedLoopNodes have as 130 // inputs the incoming loop-start control and the loop-back control, so they 131 // act like RegionNodes. They also take in the initial trip counter, the 132 // loop-invariant stride and the loop-invariant limit value. CountedLoopNodes 133 // produce a loop-body control and the trip counter value. Since 134 // CountedLoopNodes behave like RegionNodes I still have a standard CFG model. 135 136 class CountedLoopNode : public LoopNode { 137 // Size is bigger to hold _main_idx. However, _main_idx does not change 138 // the semantics so it does not appear in the hash & cmp functions. 139 virtual uint size_of() const { return sizeof(*this); } 140 141 // For Pre- and Post-loops during debugging ONLY, this holds the index of 142 // the Main CountedLoop. Used to assert that we understand the graph shape. 143 node_idx_t _main_idx; 144 145 // Known trip count calculated by compute_exact_trip_count() 146 uint _trip_count; 147 148 // Expected trip count from profile data 149 float _profile_trip_cnt; 150 151 // Log2 of original loop bodies in unrolled loop 152 int _unrolled_count_log2; 153 154 // Node count prior to last unrolling - used to decide if 155 // unroll,optimize,unroll,optimize,... is making progress 156 int _node_count_before_unroll; 157 158 public: 159 CountedLoopNode( Node *entry, Node *backedge ) 160 : LoopNode(entry, backedge), _main_idx(0), _trip_count(max_juint), 161 _profile_trip_cnt(COUNT_UNKNOWN), _unrolled_count_log2(0), 162 _node_count_before_unroll(0) { 163 init_class_id(Class_CountedLoop); 164 // Initialize _trip_count to the largest possible value. 165 // Will be reset (lower) if the loop's trip count is known. 166 } 167 168 virtual int Opcode() const; 169 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); 170 171 Node *init_control() const { return in(EntryControl); } 172 Node *back_control() const { return in(LoopBackControl); } 173 CountedLoopEndNode *loopexit() const; 174 Node *init_trip() const; 175 Node *stride() const; 176 int stride_con() const; 177 bool stride_is_con() const; 178 Node *limit() const; 179 Node *incr() const; 180 Node *phi() const; 181 182 // Match increment with optional truncation 183 static Node* match_incr_with_optional_truncation(Node* expr, Node** trunc1, Node** trunc2, const TypeInt** trunc_type); 184 185 // A 'main' loop has a pre-loop and a post-loop. The 'main' loop 186 // can run short a few iterations and may start a few iterations in. 187 // It will be RCE'd and unrolled and aligned. 188 189 // A following 'post' loop will run any remaining iterations. Used 190 // during Range Check Elimination, the 'post' loop will do any final 191 // iterations with full checks. Also used by Loop Unrolling, where 192 // the 'post' loop will do any epilog iterations needed. Basically, 193 // a 'post' loop can not profitably be further unrolled or RCE'd. 194 195 // A preceding 'pre' loop will run at least 1 iteration (to do peeling), 196 // it may do under-flow checks for RCE and may do alignment iterations 197 // so the following main loop 'knows' that it is striding down cache 198 // lines. 199 200 // A 'main' loop that is ONLY unrolled or peeled, never RCE'd or 201 // Aligned, may be missing it's pre-loop. 202 int is_normal_loop() const { return (_loop_flags&PreMainPostFlagsMask) == Normal; } 203 int is_pre_loop () const { return (_loop_flags&PreMainPostFlagsMask) == Pre; } 204 int is_main_loop () const { return (_loop_flags&PreMainPostFlagsMask) == Main; } 205 int is_post_loop () const { return (_loop_flags&PreMainPostFlagsMask) == Post; } 206 int is_main_no_pre_loop() const { return _loop_flags & MainHasNoPreLoop; } 207 void set_main_no_pre_loop() { _loop_flags |= MainHasNoPreLoop; } 208 209 int main_idx() const { return _main_idx; } 210 211 212 void set_pre_loop (CountedLoopNode *main) { assert(is_normal_loop(),""); _loop_flags |= Pre ; _main_idx = main->_idx; } 213 void set_main_loop ( ) { assert(is_normal_loop(),""); _loop_flags |= Main; } 214 void set_post_loop (CountedLoopNode *main) { assert(is_normal_loop(),""); _loop_flags |= Post; _main_idx = main->_idx; } 215 void set_normal_loop( ) { _loop_flags &= ~PreMainPostFlagsMask; } 216 217 void set_trip_count(uint tc) { _trip_count = tc; } 218 uint trip_count() { return _trip_count; } 219 220 bool has_exact_trip_count() const { return (_loop_flags & HasExactTripCount) != 0; } 221 void set_exact_trip_count(uint tc) { 222 _trip_count = tc; 223 _loop_flags |= HasExactTripCount; 224 } 225 void set_nonexact_trip_count() { 226 _loop_flags &= ~HasExactTripCount; 227 } 228 229 void set_profile_trip_cnt(float ptc) { _profile_trip_cnt = ptc; } 230 float profile_trip_cnt() { return _profile_trip_cnt; } 231 232 void double_unrolled_count() { _unrolled_count_log2++; } 233 int unrolled_count() { return 1 << MIN2(_unrolled_count_log2, BitsPerInt-3); } 234 235 void set_node_count_before_unroll(int ct) { _node_count_before_unroll = ct; } 236 int node_count_before_unroll() { return _node_count_before_unroll; } 237 238 #ifndef PRODUCT 239 virtual void dump_spec(outputStream *st) const; 240 #endif 241 }; 242 243 //------------------------------CountedLoopEndNode----------------------------- 244 // CountedLoopEndNodes end simple trip counted loops. They act much like 245 // IfNodes. 246 class CountedLoopEndNode : public IfNode { 247 public: 248 enum { TestControl, TestValue }; 249 250 CountedLoopEndNode( Node *control, Node *test, float prob, float cnt ) 251 : IfNode( control, test, prob, cnt) { 252 init_class_id(Class_CountedLoopEnd); 253 } 254 virtual int Opcode() const; 255 256 Node *cmp_node() const { return (in(TestValue)->req() >=2) ? in(TestValue)->in(1) : NULL; } 257 Node *incr() const { Node *tmp = cmp_node(); return (tmp && tmp->req()==3) ? tmp->in(1) : NULL; } 258 Node *limit() const { Node *tmp = cmp_node(); return (tmp && tmp->req()==3) ? tmp->in(2) : NULL; } 259 Node *stride() const { Node *tmp = incr (); return (tmp && tmp->req()==3) ? tmp->in(2) : NULL; } 260 Node *phi() const { Node *tmp = incr (); return (tmp && tmp->req()==3) ? tmp->in(1) : NULL; } 261 Node *init_trip() const { Node *tmp = phi (); return (tmp && tmp->req()==3) ? tmp->in(1) : NULL; } 262 int stride_con() const; 263 bool stride_is_con() const { Node *tmp = stride (); return (tmp != NULL && tmp->is_Con()); } 264 BoolTest::mask test_trip() const { return in(TestValue)->as_Bool()->_test._test; } 265 CountedLoopNode *loopnode() const { 266 Node *ln = phi()->in(0); 267 assert( ln->Opcode() == Op_CountedLoop, "malformed loop" ); 268 return (CountedLoopNode*)ln; } 269 270 #ifndef PRODUCT 271 virtual void dump_spec(outputStream *st) const; 272 #endif 273 }; 274 275 276 inline CountedLoopEndNode *CountedLoopNode::loopexit() const { 277 Node *bc = back_control(); 278 if( bc == NULL ) return NULL; 279 Node *le = bc->in(0); 280 if( le->Opcode() != Op_CountedLoopEnd ) 281 return NULL; 282 return (CountedLoopEndNode*)le; 283 } 284 inline Node *CountedLoopNode::init_trip() const { return loopexit() ? loopexit()->init_trip() : NULL; } 285 inline Node *CountedLoopNode::stride() const { return loopexit() ? loopexit()->stride() : NULL; } 286 inline int CountedLoopNode::stride_con() const { return loopexit() ? loopexit()->stride_con() : 0; } 287 inline bool CountedLoopNode::stride_is_con() const { return loopexit() && loopexit()->stride_is_con(); } 288 inline Node *CountedLoopNode::limit() const { return loopexit() ? loopexit()->limit() : NULL; } 289 inline Node *CountedLoopNode::incr() const { return loopexit() ? loopexit()->incr() : NULL; } 290 inline Node *CountedLoopNode::phi() const { return loopexit() ? loopexit()->phi() : NULL; } 291 292 //------------------------------LoopLimitNode----------------------------- 293 // Counted Loop limit node which represents exact final iterator value: 294 // trip_count = (limit - init_trip + stride - 1)/stride 295 // final_value= trip_count * stride + init_trip. 296 // Use HW instructions to calculate it when it can overflow in integer. 297 // Note, final_value should fit into integer since counted loop has 298 // limit check: limit <= max_int-stride. 299 class LoopLimitNode : public Node { 300 enum { Init=1, Limit=2, Stride=3 }; 301 public: 302 LoopLimitNode( Compile* C, Node *init, Node *limit, Node *stride ) : Node(0,init,limit,stride) { 303 // Put it on the Macro nodes list to optimize during macro nodes expansion. 304 init_flags(Flag_is_macro); 305 C->add_macro_node(this); 306 } 307 virtual int Opcode() const; 308 virtual const Type *bottom_type() const { return TypeInt::INT; } 309 virtual uint ideal_reg() const { return Op_RegI; } 310 virtual const Type *Value( PhaseTransform *phase ) const; 311 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); 312 virtual Node *Identity( PhaseTransform *phase ); 313 }; 314 315 // -----------------------------IdealLoopTree---------------------------------- 316 class IdealLoopTree : public ResourceObj { 317 public: 318 IdealLoopTree *_parent; // Parent in loop tree 319 IdealLoopTree *_next; // Next sibling in loop tree 320 IdealLoopTree *_child; // First child in loop tree 321 322 // The head-tail backedge defines the loop. 323 // If tail is NULL then this loop has multiple backedges as part of the 324 // same loop. During cleanup I'll peel off the multiple backedges; merge 325 // them at the loop bottom and flow 1 real backedge into the loop. 326 Node *_head; // Head of loop 327 Node *_tail; // Tail of loop 328 inline Node *tail(); // Handle lazy update of _tail field 329 PhaseIdealLoop* _phase; 330 331 Node_List _body; // Loop body for inner loops 332 333 uint8 _nest; // Nesting depth 334 uint8 _irreducible:1, // True if irreducible 335 _has_call:1, // True if has call safepoint 336 _has_sfpt:1, // True if has non-call safepoint 337 _rce_candidate:1; // True if candidate for range check elimination 338 339 Node_List* _required_safept; // A inner loop cannot delete these safepts; 340 bool _allow_optimizations; // Allow loop optimizations 341 342 IdealLoopTree( PhaseIdealLoop* phase, Node *head, Node *tail ) 343 : _parent(0), _next(0), _child(0), 344 _head(head), _tail(tail), 345 _phase(phase), 346 _required_safept(NULL), 347 _allow_optimizations(true), 348 _nest(0), _irreducible(0), _has_call(0), _has_sfpt(0), _rce_candidate(0) 349 { } 350 351 // Is 'l' a member of 'this'? 352 int is_member( const IdealLoopTree *l ) const; // Test for nested membership 353 354 // Set loop nesting depth. Accumulate has_call bits. 355 int set_nest( uint depth ); 356 357 // Split out multiple fall-in edges from the loop header. Move them to a 358 // private RegionNode before the loop. This becomes the loop landing pad. 359 void split_fall_in( PhaseIdealLoop *phase, int fall_in_cnt ); 360 361 // Split out the outermost loop from this shared header. 362 void split_outer_loop( PhaseIdealLoop *phase ); 363 364 // Merge all the backedges from the shared header into a private Region. 365 // Feed that region as the one backedge to this loop. 366 void merge_many_backedges( PhaseIdealLoop *phase ); 367 368 // Split shared headers and insert loop landing pads. 369 // Insert a LoopNode to replace the RegionNode. 370 // Returns TRUE if loop tree is structurally changed. 371 bool beautify_loops( PhaseIdealLoop *phase ); 372 373 // Perform optimization to use the loop predicates for null checks and range checks. 374 // Applies to any loop level (not just the innermost one) 375 bool loop_predication( PhaseIdealLoop *phase); 376 377 // Perform iteration-splitting on inner loops. Split iterations to 378 // avoid range checks or one-shot null checks. Returns false if the 379 // current round of loop opts should stop. 380 bool iteration_split( PhaseIdealLoop *phase, Node_List &old_new ); 381 382 // Driver for various flavors of iteration splitting. Returns false 383 // if the current round of loop opts should stop. 384 bool iteration_split_impl( PhaseIdealLoop *phase, Node_List &old_new ); 385 386 // Given dominators, try to find loops with calls that must always be 387 // executed (call dominates loop tail). These loops do not need non-call 388 // safepoints (ncsfpt). 389 void check_safepts(VectorSet &visited, Node_List &stack); 390 391 // Allpaths backwards scan from loop tail, terminating each path at first safepoint 392 // encountered. 393 void allpaths_check_safepts(VectorSet &visited, Node_List &stack); 394 395 // Convert to counted loops where possible 396 void counted_loop( PhaseIdealLoop *phase ); 397 398 // Check for Node being a loop-breaking test 399 Node *is_loop_exit(Node *iff) const; 400 401 // Returns true if ctrl is executed on every complete iteration 402 bool dominates_backedge(Node* ctrl); 403 404 // Remove simplistic dead code from loop body 405 void DCE_loop_body(); 406 407 // Look for loop-exit tests with my 50/50 guesses from the Parsing stage. 408 // Replace with a 1-in-10 exit guess. 409 void adjust_loop_exit_prob( PhaseIdealLoop *phase ); 410 411 // Return TRUE or FALSE if the loop should never be RCE'd or aligned. 412 // Useful for unrolling loops with NO array accesses. 413 bool policy_peel_only( PhaseIdealLoop *phase ) const; 414 415 // Return TRUE or FALSE if the loop should be unswitched -- clone 416 // loop with an invariant test 417 bool policy_unswitching( PhaseIdealLoop *phase ) const; 418 419 // Micro-benchmark spamming. Remove empty loops. 420 bool policy_do_remove_empty_loop( PhaseIdealLoop *phase ); 421 422 // Convert one iteration loop into normal code. 423 bool policy_do_one_iteration_loop( PhaseIdealLoop *phase ); 424 425 // Return TRUE or FALSE if the loop should be peeled or not. Peel if we can 426 // make some loop-invariant test (usually a null-check) happen before the 427 // loop. 428 bool policy_peeling( PhaseIdealLoop *phase ) const; 429 430 // Return TRUE or FALSE if the loop should be maximally unrolled. Stash any 431 // known trip count in the counted loop node. 432 bool policy_maximally_unroll( PhaseIdealLoop *phase ) const; 433 434 // Return TRUE or FALSE if the loop should be unrolled or not. Unroll if 435 // the loop is a CountedLoop and the body is small enough. 436 bool policy_unroll( PhaseIdealLoop *phase ) const; 437 438 // Return TRUE or FALSE if the loop should be range-check-eliminated. 439 // Gather a list of IF tests that are dominated by iteration splitting; 440 // also gather the end of the first split and the start of the 2nd split. 441 bool policy_range_check( PhaseIdealLoop *phase ) const; 442 443 // Return TRUE or FALSE if the loop should be cache-line aligned. 444 // Gather the expression that does the alignment. Note that only 445 // one array base can be aligned in a loop (unless the VM guarantees 446 // mutual alignment). Note that if we vectorize short memory ops 447 // into longer memory ops, we may want to increase alignment. 448 bool policy_align( PhaseIdealLoop *phase ) const; 449 450 // Return TRUE if "iff" is a range check. 451 bool is_range_check_if(IfNode *iff, PhaseIdealLoop *phase, Invariance& invar) const; 452 453 // Compute loop exact trip count if possible 454 void compute_exact_trip_count( PhaseIdealLoop *phase ); 455 456 // Compute loop trip count from profile data 457 void compute_profile_trip_cnt( PhaseIdealLoop *phase ); 458 459 // Reassociate invariant expressions. 460 void reassociate_invariants(PhaseIdealLoop *phase); 461 // Reassociate invariant add and subtract expressions. 462 Node* reassociate_add_sub(Node* n1, PhaseIdealLoop *phase); 463 // Return nonzero index of invariant operand if invariant and variant 464 // are combined with an Add or Sub. Helper for reassociate_invariants. 465 int is_invariant_addition(Node* n, PhaseIdealLoop *phase); 466 467 // Return true if n is invariant 468 bool is_invariant(Node* n) const; 469 470 // Put loop body on igvn work list 471 void record_for_igvn(); 472 473 bool is_loop() { return !_irreducible && _tail && !_tail->is_top(); } 474 bool is_inner() { return is_loop() && _child == NULL; } 475 bool is_counted() { return is_loop() && _head != NULL && _head->is_CountedLoop(); } 476 477 #ifndef PRODUCT 478 void dump_head( ) const; // Dump loop head only 479 void dump() const; // Dump this loop recursively 480 void verify_tree(IdealLoopTree *loop, const IdealLoopTree *parent) const; 481 #endif 482 483 }; 484 485 // -----------------------------PhaseIdealLoop--------------------------------- 486 // Computes the mapping from Nodes to IdealLoopTrees. Organizes IdealLoopTrees into a 487 // loop tree. Drives the loop-based transformations on the ideal graph. 488 class PhaseIdealLoop : public PhaseTransform { 489 friend class IdealLoopTree; 490 friend class SuperWord; 491 // Pre-computed def-use info 492 PhaseIterGVN &_igvn; 493 494 // Head of loop tree 495 IdealLoopTree *_ltree_root; 496 497 // Array of pre-order numbers, plus post-visited bit. 498 // ZERO for not pre-visited. EVEN for pre-visited but not post-visited. 499 // ODD for post-visited. Other bits are the pre-order number. 500 uint *_preorders; 501 uint _max_preorder; 502 503 const PhaseIdealLoop* _verify_me; 504 bool _verify_only; 505 506 // Allocate _preorders[] array 507 void allocate_preorders() { 508 _max_preorder = C->unique()+8; 509 _preorders = NEW_RESOURCE_ARRAY(uint, _max_preorder); 510 memset(_preorders, 0, sizeof(uint) * _max_preorder); 511 } 512 513 // Allocate _preorders[] array 514 void reallocate_preorders() { 515 if ( _max_preorder < C->unique() ) { 516 _preorders = REALLOC_RESOURCE_ARRAY(uint, _preorders, _max_preorder, C->unique()); 517 _max_preorder = C->unique(); 518 } 519 memset(_preorders, 0, sizeof(uint) * _max_preorder); 520 } 521 522 // Check to grow _preorders[] array for the case when build_loop_tree_impl() 523 // adds new nodes. 524 void check_grow_preorders( ) { 525 if ( _max_preorder < C->unique() ) { 526 uint newsize = _max_preorder<<1; // double size of array 527 _preorders = REALLOC_RESOURCE_ARRAY(uint, _preorders, _max_preorder, newsize); 528 memset(&_preorders[_max_preorder],0,sizeof(uint)*(newsize-_max_preorder)); 529 _max_preorder = newsize; 530 } 531 } 532 // Check for pre-visited. Zero for NOT visited; non-zero for visited. 533 int is_visited( Node *n ) const { return _preorders[n->_idx]; } 534 // Pre-order numbers are written to the Nodes array as low-bit-set values. 535 void set_preorder_visited( Node *n, int pre_order ) { 536 assert( !is_visited( n ), "already set" ); 537 _preorders[n->_idx] = (pre_order<<1); 538 }; 539 // Return pre-order number. 540 int get_preorder( Node *n ) const { assert( is_visited(n), "" ); return _preorders[n->_idx]>>1; } 541 542 // Check for being post-visited. 543 // Should be previsited already (checked with assert(is_visited(n))). 544 int is_postvisited( Node *n ) const { assert( is_visited(n), "" ); return _preorders[n->_idx]&1; } 545 546 // Mark as post visited 547 void set_postvisited( Node *n ) { assert( !is_postvisited( n ), "" ); _preorders[n->_idx] |= 1; } 548 549 // Set/get control node out. Set lower bit to distinguish from IdealLoopTree 550 // Returns true if "n" is a data node, false if it's a control node. 551 bool has_ctrl( Node *n ) const { return ((intptr_t)_nodes[n->_idx]) & 1; } 552 553 // clear out dead code after build_loop_late 554 Node_List _deadlist; 555 556 // Support for faster execution of get_late_ctrl()/dom_lca() 557 // when a node has many uses and dominator depth is deep. 558 Node_Array _dom_lca_tags; 559 void init_dom_lca_tags(); 560 void clear_dom_lca_tags(); 561 562 // Helper for debugging bad dominance relationships 563 bool verify_dominance(Node* n, Node* use, Node* LCA, Node* early); 564 565 Node* compute_lca_of_uses(Node* n, Node* early, bool verify = false); 566 567 // Inline wrapper for frequent cases: 568 // 1) only one use 569 // 2) a use is the same as the current LCA passed as 'n1' 570 Node *dom_lca_for_get_late_ctrl( Node *lca, Node *n, Node *tag ) { 571 assert( n->is_CFG(), "" ); 572 // Fast-path NULL lca 573 if( lca != NULL && lca != n ) { 574 assert( lca->is_CFG(), "" ); 575 // find LCA of all uses 576 n = dom_lca_for_get_late_ctrl_internal( lca, n, tag ); 577 } 578 return find_non_split_ctrl(n); 579 } 580 Node *dom_lca_for_get_late_ctrl_internal( Node *lca, Node *n, Node *tag ); 581 582 // Helper function for directing control inputs away from CFG split 583 // points. 584 Node *find_non_split_ctrl( Node *ctrl ) const { 585 if (ctrl != NULL) { 586 if (ctrl->is_MultiBranch()) { 587 ctrl = ctrl->in(0); 588 } 589 assert(ctrl->is_CFG(), "CFG"); 590 } 591 return ctrl; 592 } 593 594 public: 595 bool has_node( Node* n ) const { return _nodes[n->_idx] != NULL; } 596 // check if transform created new nodes that need _ctrl recorded 597 Node *get_late_ctrl( Node *n, Node *early ); 598 Node *get_early_ctrl( Node *n ); 599 void set_early_ctrl( Node *n ); 600 void set_subtree_ctrl( Node *root ); 601 void set_ctrl( Node *n, Node *ctrl ) { 602 assert( !has_node(n) || has_ctrl(n), "" ); 603 assert( ctrl->in(0), "cannot set dead control node" ); 604 assert( ctrl == find_non_split_ctrl(ctrl), "must set legal crtl" ); 605 _nodes.map( n->_idx, (Node*)((intptr_t)ctrl + 1) ); 606 } 607 // Set control and update loop membership 608 void set_ctrl_and_loop(Node* n, Node* ctrl) { 609 IdealLoopTree* old_loop = get_loop(get_ctrl(n)); 610 IdealLoopTree* new_loop = get_loop(ctrl); 611 if (old_loop != new_loop) { 612 if (old_loop->_child == NULL) old_loop->_body.yank(n); 613 if (new_loop->_child == NULL) new_loop->_body.push(n); 614 } 615 set_ctrl(n, ctrl); 616 } 617 // Control nodes can be replaced or subsumed. During this pass they 618 // get their replacement Node in slot 1. Instead of updating the block 619 // location of all Nodes in the subsumed block, we lazily do it. As we 620 // pull such a subsumed block out of the array, we write back the final 621 // correct block. 622 Node *get_ctrl( Node *i ) { 623 assert(has_node(i), ""); 624 Node *n = get_ctrl_no_update(i); 625 _nodes.map( i->_idx, (Node*)((intptr_t)n + 1) ); 626 assert(has_node(i) && has_ctrl(i), ""); 627 assert(n == find_non_split_ctrl(n), "must return legal ctrl" ); 628 return n; 629 } 630 // true if CFG node d dominates CFG node n 631 bool is_dominator(Node *d, Node *n); 632 // return get_ctrl for a data node and self(n) for a CFG node 633 Node* ctrl_or_self(Node* n) { 634 if (has_ctrl(n)) 635 return get_ctrl(n); 636 else { 637 assert (n->is_CFG(), "must be a CFG node"); 638 return n; 639 } 640 } 641 642 private: 643 Node *get_ctrl_no_update( Node *i ) const { 644 assert( has_ctrl(i), "" ); 645 Node *n = (Node*)(((intptr_t)_nodes[i->_idx]) & ~1); 646 if (!n->in(0)) { 647 // Skip dead CFG nodes 648 do { 649 n = (Node*)(((intptr_t)_nodes[n->_idx]) & ~1); 650 } while (!n->in(0)); 651 n = find_non_split_ctrl(n); 652 } 653 return n; 654 } 655 656 // Check for loop being set 657 // "n" must be a control node. Returns true if "n" is known to be in a loop. 658 bool has_loop( Node *n ) const { 659 assert(!has_node(n) || !has_ctrl(n), ""); 660 return has_node(n); 661 } 662 // Set loop 663 void set_loop( Node *n, IdealLoopTree *loop ) { 664 _nodes.map(n->_idx, (Node*)loop); 665 } 666 // Lazy-dazy update of 'get_ctrl' and 'idom_at' mechanisms. Replace 667 // the 'old_node' with 'new_node'. Kill old-node. Add a reference 668 // from old_node to new_node to support the lazy update. Reference 669 // replaces loop reference, since that is not needed for dead node. 670 public: 671 void lazy_update( Node *old_node, Node *new_node ) { 672 assert( old_node != new_node, "no cycles please" ); 673 //old_node->set_req( 1, new_node /*NO DU INFO*/ ); 674 // Nodes always have DU info now, so re-use the side array slot 675 // for this node to provide the forwarding pointer. 676 _nodes.map( old_node->_idx, (Node*)((intptr_t)new_node + 1) ); 677 } 678 void lazy_replace( Node *old_node, Node *new_node ) { 679 _igvn.replace_node( old_node, new_node ); 680 lazy_update( old_node, new_node ); 681 } 682 void lazy_replace_proj( Node *old_node, Node *new_node ) { 683 assert( old_node->req() == 1, "use this for Projs" ); 684 _igvn.hash_delete(old_node); // Must hash-delete before hacking edges 685 old_node->add_req( NULL ); 686 lazy_replace( old_node, new_node ); 687 } 688 689 private: 690 691 // Place 'n' in some loop nest, where 'n' is a CFG node 692 void build_loop_tree(); 693 int build_loop_tree_impl( Node *n, int pre_order ); 694 // Insert loop into the existing loop tree. 'innermost' is a leaf of the 695 // loop tree, not the root. 696 IdealLoopTree *sort( IdealLoopTree *loop, IdealLoopTree *innermost ); 697 698 // Place Data nodes in some loop nest 699 void build_loop_early( VectorSet &visited, Node_List &worklist, Node_Stack &nstack ); 700 void build_loop_late ( VectorSet &visited, Node_List &worklist, Node_Stack &nstack ); 701 void build_loop_late_post ( Node* n ); 702 703 // Array of immediate dominance info for each CFG node indexed by node idx 704 private: 705 uint _idom_size; 706 Node **_idom; // Array of immediate dominators 707 uint *_dom_depth; // Used for fast LCA test 708 GrowableArray<uint>* _dom_stk; // For recomputation of dom depth 709 710 Node* idom_no_update(Node* d) const { 711 assert(d->_idx < _idom_size, "oob"); 712 Node* n = _idom[d->_idx]; 713 assert(n != NULL,"Bad immediate dominator info."); 714 while (n->in(0) == NULL) { // Skip dead CFG nodes 715 //n = n->in(1); 716 n = (Node*)(((intptr_t)_nodes[n->_idx]) & ~1); 717 assert(n != NULL,"Bad immediate dominator info."); 718 } 719 return n; 720 } 721 Node *idom(Node* d) const { 722 uint didx = d->_idx; 723 Node *n = idom_no_update(d); 724 _idom[didx] = n; // Lazily remove dead CFG nodes from table. 725 return n; 726 } 727 uint dom_depth(Node* d) const { 728 assert(d->_idx < _idom_size, ""); 729 return _dom_depth[d->_idx]; 730 } 731 void set_idom(Node* d, Node* n, uint dom_depth); 732 // Locally compute IDOM using dom_lca call 733 Node *compute_idom( Node *region ) const; 734 // Recompute dom_depth 735 void recompute_dom_depth(); 736 737 // Is safept not required by an outer loop? 738 bool is_deleteable_safept(Node* sfpt); 739 740 // Replace parallel induction variable (parallel to trip counter) 741 void replace_parallel_iv(IdealLoopTree *loop); 742 743 // Perform verification that the graph is valid. 744 PhaseIdealLoop( PhaseIterGVN &igvn) : 745 PhaseTransform(Ideal_Loop), 746 _igvn(igvn), 747 _dom_lca_tags(arena()), // Thread::resource_area 748 _verify_me(NULL), 749 _verify_only(true) { 750 build_and_optimize(false); 751 } 752 753 // build the loop tree and perform any requested optimizations 754 void build_and_optimize(bool do_split_if); 755 756 public: 757 // Dominators for the sea of nodes 758 void Dominators(); 759 Node *dom_lca( Node *n1, Node *n2 ) const { 760 return find_non_split_ctrl(dom_lca_internal(n1, n2)); 761 } 762 Node *dom_lca_internal( Node *n1, Node *n2 ) const; 763 764 // Compute the Ideal Node to Loop mapping 765 PhaseIdealLoop( PhaseIterGVN &igvn, bool do_split_ifs) : 766 PhaseTransform(Ideal_Loop), 767 _igvn(igvn), 768 _dom_lca_tags(arena()), // Thread::resource_area 769 _verify_me(NULL), 770 _verify_only(false) { 771 build_and_optimize(do_split_ifs); 772 } 773 774 // Verify that verify_me made the same decisions as a fresh run. 775 PhaseIdealLoop( PhaseIterGVN &igvn, const PhaseIdealLoop *verify_me) : 776 PhaseTransform(Ideal_Loop), 777 _igvn(igvn), 778 _dom_lca_tags(arena()), // Thread::resource_area 779 _verify_me(verify_me), 780 _verify_only(false) { 781 build_and_optimize(false); 782 } 783 784 // Build and verify the loop tree without modifying the graph. This 785 // is useful to verify that all inputs properly dominate their uses. 786 static void verify(PhaseIterGVN& igvn) { 787 #ifdef ASSERT 788 PhaseIdealLoop v(igvn); 789 #endif 790 } 791 792 // True if the method has at least 1 irreducible loop 793 bool _has_irreducible_loops; 794 795 // Per-Node transform 796 virtual Node *transform( Node *a_node ) { return 0; } 797 798 bool is_counted_loop( Node *x, IdealLoopTree *loop ); 799 800 Node* exact_limit( IdealLoopTree *loop ); 801 802 // Return a post-walked LoopNode 803 IdealLoopTree *get_loop( Node *n ) const { 804 // Dead nodes have no loop, so return the top level loop instead 805 if (!has_node(n)) return _ltree_root; 806 assert(!has_ctrl(n), ""); 807 return (IdealLoopTree*)_nodes[n->_idx]; 808 } 809 810 // Is 'n' a (nested) member of 'loop'? 811 int is_member( const IdealLoopTree *loop, Node *n ) const { 812 return loop->is_member(get_loop(n)); } 813 814 // This is the basic building block of the loop optimizations. It clones an 815 // entire loop body. It makes an old_new loop body mapping; with this 816 // mapping you can find the new-loop equivalent to an old-loop node. All 817 // new-loop nodes are exactly equal to their old-loop counterparts, all 818 // edges are the same. All exits from the old-loop now have a RegionNode 819 // that merges the equivalent new-loop path. This is true even for the 820 // normal "loop-exit" condition. All uses of loop-invariant old-loop values 821 // now come from (one or more) Phis that merge their new-loop equivalents. 822 // Parameter side_by_side_idom: 823 // When side_by_size_idom is NULL, the dominator tree is constructed for 824 // the clone loop to dominate the original. Used in construction of 825 // pre-main-post loop sequence. 826 // When nonnull, the clone and original are side-by-side, both are 827 // dominated by the passed in side_by_side_idom node. Used in 828 // construction of unswitched loops. 829 void clone_loop( IdealLoopTree *loop, Node_List &old_new, int dom_depth, 830 Node* side_by_side_idom = NULL); 831 832 // If we got the effect of peeling, either by actually peeling or by 833 // making a pre-loop which must execute at least once, we can remove 834 // all loop-invariant dominated tests in the main body. 835 void peeled_dom_test_elim( IdealLoopTree *loop, Node_List &old_new ); 836 837 // Generate code to do a loop peel for the given loop (and body). 838 // old_new is a temp array. 839 void do_peeling( IdealLoopTree *loop, Node_List &old_new ); 840 841 // Add pre and post loops around the given loop. These loops are used 842 // during RCE, unrolling and aligning loops. 843 void insert_pre_post_loops( IdealLoopTree *loop, Node_List &old_new, bool peel_only ); 844 // If Node n lives in the back_ctrl block, we clone a private version of n 845 // in preheader_ctrl block and return that, otherwise return n. 846 Node *clone_up_backedge_goo( Node *back_ctrl, Node *preheader_ctrl, Node *n, VectorSet &visited, Node_Stack &clones ); 847 848 // Take steps to maximally unroll the loop. Peel any odd iterations, then 849 // unroll to do double iterations. The next round of major loop transforms 850 // will repeat till the doubled loop body does all remaining iterations in 1 851 // pass. 852 void do_maximally_unroll( IdealLoopTree *loop, Node_List &old_new ); 853 854 // Unroll the loop body one step - make each trip do 2 iterations. 855 void do_unroll( IdealLoopTree *loop, Node_List &old_new, bool adjust_min_trip ); 856 857 // Return true if exp is a constant times an induction var 858 bool is_scaled_iv(Node* exp, Node* iv, int* p_scale); 859 860 // Return true if exp is a scaled induction var plus (or minus) constant 861 bool is_scaled_iv_plus_offset(Node* exp, Node* iv, int* p_scale, Node** p_offset, int depth = 0); 862 863 // Return true if proj is for "proj->[region->..]call_uct" 864 static bool is_uncommon_trap_proj(ProjNode* proj, Deoptimization::DeoptReason reason); 865 // Return true for "if(test)-> proj -> ... 866 // | 867 // V 868 // other_proj->[region->..]call_uct" 869 static bool is_uncommon_trap_if_pattern(ProjNode* proj, Deoptimization::DeoptReason reason); 870 // Create a new if above the uncommon_trap_if_pattern for the predicate to be promoted 871 ProjNode* create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, 872 Deoptimization::DeoptReason reason); 873 void register_control(Node* n, IdealLoopTree *loop, Node* pred); 874 875 // Clone loop predicates to cloned loops (peeled, unswitched) 876 static ProjNode* clone_predicate(ProjNode* predicate_proj, Node* new_entry, 877 Deoptimization::DeoptReason reason, 878 PhaseIdealLoop* loop_phase, 879 PhaseIterGVN* igvn); 880 881 static Node* clone_loop_predicates(Node* old_entry, Node* new_entry, 882 bool clone_limit_check, 883 PhaseIdealLoop* loop_phase, 884 PhaseIterGVN* igvn); 885 Node* clone_loop_predicates(Node* old_entry, Node* new_entry, bool clone_limit_check); 886 887 static Node* skip_loop_predicates(Node* entry); 888 889 // Find a good location to insert a predicate 890 static ProjNode* find_predicate_insertion_point(Node* start_c, Deoptimization::DeoptReason reason); 891 // Find a predicate 892 static Node* find_predicate(Node* entry); 893 // Construct a range check for a predicate if 894 BoolNode* rc_predicate(IdealLoopTree *loop, Node* ctrl, 895 int scale, Node* offset, 896 Node* init, Node* limit, Node* stride, 897 Node* range, bool upper); 898 899 // Implementation of the loop predication to promote checks outside the loop 900 bool loop_predication_impl(IdealLoopTree *loop); 901 902 // Helper function to collect predicate for eliminating the useless ones 903 void collect_potentially_useful_predicates(IdealLoopTree *loop, Unique_Node_List &predicate_opaque1); 904 void eliminate_useless_predicates(); 905 906 // Eliminate range-checks and other trip-counter vs loop-invariant tests. 907 void do_range_check( IdealLoopTree *loop, Node_List &old_new ); 908 909 // Create a slow version of the loop by cloning the loop 910 // and inserting an if to select fast-slow versions. 911 ProjNode* create_slow_version_of_loop(IdealLoopTree *loop, 912 Node_List &old_new); 913 914 // Clone loop with an invariant test (that does not exit) and 915 // insert a clone of the test that selects which version to 916 // execute. 917 void do_unswitching (IdealLoopTree *loop, Node_List &old_new); 918 919 // Find candidate "if" for unswitching 920 IfNode* find_unswitching_candidate(const IdealLoopTree *loop) const; 921 922 // Range Check Elimination uses this function! 923 // Constrain the main loop iterations so the affine function: 924 // low_limit <= scale_con * I + offset < upper_limit 925 // always holds true. That is, either increase the number of iterations in 926 // the pre-loop or the post-loop until the condition holds true in the main 927 // loop. Scale_con, offset and limit are all loop invariant. 928 void add_constraint( int stride_con, int scale_con, Node *offset, Node *low_limit, Node *upper_limit, Node *pre_ctrl, Node **pre_limit, Node **main_limit ); 929 // Helper function for add_constraint(). 930 Node* adjust_limit( int stride_con, Node * scale, Node *offset, Node *rc_limit, Node *loop_limit, Node *pre_ctrl ); 931 932 // Partially peel loop up through last_peel node. 933 bool partial_peel( IdealLoopTree *loop, Node_List &old_new ); 934 935 // Create a scheduled list of nodes control dependent on ctrl set. 936 void scheduled_nodelist( IdealLoopTree *loop, VectorSet& ctrl, Node_List &sched ); 937 // Has a use in the vector set 938 bool has_use_in_set( Node* n, VectorSet& vset ); 939 // Has use internal to the vector set (ie. not in a phi at the loop head) 940 bool has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ); 941 // clone "n" for uses that are outside of loop 942 void clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ); 943 // clone "n" for special uses that are in the not_peeled region 944 void clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, 945 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ); 946 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist 947 void insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ); 948 #ifdef ASSERT 949 // Validate the loop partition sets: peel and not_peel 950 bool is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, VectorSet& not_peel ); 951 // Ensure that uses outside of loop are of the right form 952 bool is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, 953 uint orig_exit_idx, uint clone_exit_idx); 954 bool is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx); 955 #endif 956 957 // Returns nonzero constant stride if-node is a possible iv test (otherwise returns zero.) 958 int stride_of_possible_iv( Node* iff ); 959 bool is_possible_iv_test( Node* iff ) { return stride_of_possible_iv(iff) != 0; } 960 // Return the (unique) control output node that's in the loop (if it exists.) 961 Node* stay_in_loop( Node* n, IdealLoopTree *loop); 962 // Insert a signed compare loop exit cloned from an unsigned compare. 963 IfNode* insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop); 964 void remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop); 965 // Utility to register node "n" with PhaseIdealLoop 966 void register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth); 967 // Utility to create an if-projection 968 ProjNode* proj_clone(ProjNode* p, IfNode* iff); 969 // Force the iff control output to be the live_proj 970 Node* short_circuit_if(IfNode* iff, ProjNode* live_proj); 971 // Insert a region before an if projection 972 RegionNode* insert_region_before_proj(ProjNode* proj); 973 // Insert a new if before an if projection 974 ProjNode* insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj); 975 976 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. 977 // "Nearly" because all Nodes have been cloned from the original in the loop, 978 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs 979 // through the Phi recursively, and return a Bool. 980 BoolNode *clone_iff( PhiNode *phi, IdealLoopTree *loop ); 981 CmpNode *clone_bool( PhiNode *phi, IdealLoopTree *loop ); 982 983 984 // Rework addressing expressions to get the most loop-invariant stuff 985 // moved out. We'd like to do all associative operators, but it's especially 986 // important (common) to do address expressions. 987 Node *remix_address_expressions( Node *n ); 988 989 // Attempt to use a conditional move instead of a phi/branch 990 Node *conditional_move( Node *n ); 991 992 // Reorganize offset computations to lower register pressure. 993 // Mostly prevent loop-fallout uses of the pre-incremented trip counter 994 // (which are then alive with the post-incremented trip counter 995 // forcing an extra register move) 996 void reorg_offsets( IdealLoopTree *loop ); 997 998 // Check for aggressive application of 'split-if' optimization, 999 // using basic block level info. 1000 void split_if_with_blocks ( VectorSet &visited, Node_Stack &nstack ); 1001 Node *split_if_with_blocks_pre ( Node *n ); 1002 void split_if_with_blocks_post( Node *n ); 1003 Node *has_local_phi_input( Node *n ); 1004 // Mark an IfNode as being dominated by a prior test, 1005 // without actually altering the CFG (and hence IDOM info). 1006 void dominated_by( Node *prevdom, Node *iff, bool flip = false ); 1007 1008 // Split Node 'n' through merge point 1009 Node *split_thru_region( Node *n, Node *region ); 1010 // Split Node 'n' through merge point if there is enough win. 1011 Node *split_thru_phi( Node *n, Node *region, int policy ); 1012 // Found an If getting its condition-code input from a Phi in the 1013 // same block. Split thru the Region. 1014 void do_split_if( Node *iff ); 1015 1016 // Conversion of fill/copy patterns into intrisic versions 1017 bool do_intrinsify_fill(); 1018 bool intrinsify_fill(IdealLoopTree* lpt); 1019 bool match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& store_value, 1020 Node*& shift, Node*& offset); 1021 1022 private: 1023 // Return a type based on condition control flow 1024 const TypeInt* filtered_type( Node *n, Node* n_ctrl); 1025 const TypeInt* filtered_type( Node *n ) { return filtered_type(n, NULL); } 1026 // Helpers for filtered type 1027 const TypeInt* filtered_type_from_dominators( Node* val, Node *val_ctrl); 1028 1029 // Helper functions 1030 Node *spinup( Node *iff, Node *new_false, Node *new_true, Node *region, Node *phi, small_cache *cache ); 1031 Node *find_use_block( Node *use, Node *def, Node *old_false, Node *new_false, Node *old_true, Node *new_true ); 1032 void handle_use( Node *use, Node *def, small_cache *cache, Node *region_dom, Node *new_false, Node *new_true, Node *old_false, Node *old_true ); 1033 bool split_up( Node *n, Node *blk1, Node *blk2 ); 1034 void sink_use( Node *use, Node *post_loop ); 1035 Node *place_near_use( Node *useblock ) const; 1036 1037 bool _created_loop_node; 1038 public: 1039 void set_created_loop_node() { _created_loop_node = true; } 1040 bool created_loop_node() { return _created_loop_node; } 1041 void register_new_node( Node *n, Node *blk ); 1042 1043 #ifndef PRODUCT 1044 void dump( ) const; 1045 void dump( IdealLoopTree *loop, uint rpo_idx, Node_List &rpo_list ) const; 1046 void rpo( Node *start, Node_Stack &stk, VectorSet &visited, Node_List &rpo_list ) const; 1047 void verify() const; // Major slow :-) 1048 void verify_compare( Node *n, const PhaseIdealLoop *loop_verify, VectorSet &visited ) const; 1049 IdealLoopTree *get_loop_idx(Node* n) const { 1050 // Dead nodes have no loop, so return the top level loop instead 1051 return _nodes[n->_idx] ? (IdealLoopTree*)_nodes[n->_idx] : _ltree_root; 1052 } 1053 // Print some stats 1054 static void print_statistics(); 1055 static int _loop_invokes; // Count of PhaseIdealLoop invokes 1056 static int _loop_work; // Sum of PhaseIdealLoop x _unique 1057 #endif 1058 }; 1059 1060 inline Node* IdealLoopTree::tail() { 1061 // Handle lazy update of _tail field 1062 Node *n = _tail; 1063 //while( !n->in(0) ) // Skip dead CFG nodes 1064 //n = n->in(1); 1065 if (n->in(0) == NULL) 1066 n = _phase->get_ctrl(n); 1067 _tail = n; 1068 return n; 1069 } 1070 1071 1072 // Iterate over the loop tree using a preorder, left-to-right traversal. 1073 // 1074 // Example that visits all counted loops from within PhaseIdealLoop 1075 // 1076 // for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { 1077 // IdealLoopTree* lpt = iter.current(); 1078 // if (!lpt->is_counted()) continue; 1079 // ... 1080 class LoopTreeIterator : public StackObj { 1081 private: 1082 IdealLoopTree* _root; 1083 IdealLoopTree* _curnt; 1084 1085 public: 1086 LoopTreeIterator(IdealLoopTree* root) : _root(root), _curnt(root) {} 1087 1088 bool done() { return _curnt == NULL; } // Finished iterating? 1089 1090 void next(); // Advance to next loop tree 1091 1092 IdealLoopTree* current() { return _curnt; } // Return current value of iterator. 1093 }; 1094 1095 #endif // SHARE_VM_OPTO_LOOPNODE_HPP