1 /*
2 * Copyright (c) 1997, 2017, 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 "memory/allocation.inline.hpp"
27 #include "memory/resourceArea.hpp"
28 #include "opto/block.hpp"
29 #include "opto/callnode.hpp"
30 #include "opto/castnode.hpp"
31 #include "opto/cfgnode.hpp"
32 #include "opto/idealGraphPrinter.hpp"
33 #include "opto/loopnode.hpp"
34 #include "opto/machnode.hpp"
35 #include "opto/opcodes.hpp"
36 #include "opto/phaseX.hpp"
37 #include "opto/regalloc.hpp"
38 #include "opto/rootnode.hpp"
39
40 //=============================================================================
41 #define NODE_HASH_MINIMUM_SIZE 255
42 //------------------------------NodeHash---------------------------------------
43 NodeHash::NodeHash(uint est_max_size) :
44 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
45 _a(Thread::current()->resource_area()),
46 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), // (Node**)_a->Amalloc(_max * sizeof(Node*)) ),
47 _inserts(0), _insert_limit( insert_limit() )
48 #ifndef PRODUCT
49 ,_look_probes(0), _lookup_hits(0), _lookup_misses(0),
50 _delete_probes(0), _delete_hits(0), _delete_misses(0),
51 _total_insert_probes(0), _total_inserts(0),
52 _insert_probes(0), _grows(0)
53 #endif
54 {
55 // _sentinel must be in the current node space
56 _sentinel = new ProjNode(NULL, TypeFunc::Control);
57 memset(_table,0,sizeof(Node*)*_max);
58 }
59
60 //------------------------------NodeHash---------------------------------------
61 NodeHash::NodeHash(Arena *arena, uint est_max_size) :
62 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
63 _a(arena),
64 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ),
65 _inserts(0), _insert_limit( insert_limit() )
66 #ifndef PRODUCT
67 ,_look_probes(0), _lookup_hits(0), _lookup_misses(0),
68 _delete_probes(0), _delete_hits(0), _delete_misses(0),
69 _total_insert_probes(0), _total_inserts(0),
70 _insert_probes(0), _grows(0)
71 #endif
72 {
73 // _sentinel must be in the current node space
74 _sentinel = new ProjNode(NULL, TypeFunc::Control);
75 memset(_table,0,sizeof(Node*)*_max);
76 }
77
78 //------------------------------NodeHash---------------------------------------
79 NodeHash::NodeHash(NodeHash *nh) {
80 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
81 // just copy in all the fields
82 *this = *nh;
83 // nh->_sentinel must be in the current node space
84 }
85
86 void NodeHash::replace_with(NodeHash *nh) {
87 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
88 // just copy in all the fields
89 *this = *nh;
90 // nh->_sentinel must be in the current node space
91 }
92
93 //------------------------------hash_find--------------------------------------
94 // Find in hash table
95 Node *NodeHash::hash_find( const Node *n ) {
96 // ((Node*)n)->set_hash( n->hash() );
97 uint hash = n->hash();
98 if (hash == Node::NO_HASH) {
99 NOT_PRODUCT( _lookup_misses++ );
100 return NULL;
101 }
102 uint key = hash & (_max-1);
103 uint stride = key | 0x01;
104 NOT_PRODUCT( _look_probes++ );
105 Node *k = _table[key]; // Get hashed value
106 if( !k ) { // ?Miss?
107 NOT_PRODUCT( _lookup_misses++ );
108 return NULL; // Miss!
109 }
110
111 int op = n->Opcode();
112 uint req = n->req();
113 while( 1 ) { // While probing hash table
114 if( k->req() == req && // Same count of inputs
115 k->Opcode() == op ) { // Same Opcode
116 for( uint i=0; i<req; i++ )
117 if( n->in(i)!=k->in(i)) // Different inputs?
118 goto collision; // "goto" is a speed hack...
119 if( n->cmp(*k) ) { // Check for any special bits
120 NOT_PRODUCT( _lookup_hits++ );
121 return k; // Hit!
122 }
123 }
124 collision:
125 NOT_PRODUCT( _look_probes++ );
126 key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime
127 k = _table[key]; // Get hashed value
128 if( !k ) { // ?Miss?
129 NOT_PRODUCT( _lookup_misses++ );
130 return NULL; // Miss!
131 }
132 }
133 ShouldNotReachHere();
134 return NULL;
135 }
136
137 //------------------------------hash_find_insert-------------------------------
138 // Find in hash table, insert if not already present
139 // Used to preserve unique entries in hash table
140 Node *NodeHash::hash_find_insert( Node *n ) {
141 // n->set_hash( );
142 uint hash = n->hash();
143 if (hash == Node::NO_HASH) {
144 NOT_PRODUCT( _lookup_misses++ );
145 return NULL;
146 }
147 uint key = hash & (_max-1);
148 uint stride = key | 0x01; // stride must be relatively prime to table siz
149 uint first_sentinel = 0; // replace a sentinel if seen.
150 NOT_PRODUCT( _look_probes++ );
151 Node *k = _table[key]; // Get hashed value
152 if( !k ) { // ?Miss?
153 NOT_PRODUCT( _lookup_misses++ );
154 _table[key] = n; // Insert into table!
155 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
156 check_grow(); // Grow table if insert hit limit
157 return NULL; // Miss!
158 }
159 else if( k == _sentinel ) {
160 first_sentinel = key; // Can insert here
161 }
162
163 int op = n->Opcode();
164 uint req = n->req();
165 while( 1 ) { // While probing hash table
166 if( k->req() == req && // Same count of inputs
167 k->Opcode() == op ) { // Same Opcode
168 for( uint i=0; i<req; i++ )
169 if( n->in(i)!=k->in(i)) // Different inputs?
170 goto collision; // "goto" is a speed hack...
171 if( n->cmp(*k) ) { // Check for any special bits
172 NOT_PRODUCT( _lookup_hits++ );
173 return k; // Hit!
174 }
175 }
176 collision:
177 NOT_PRODUCT( _look_probes++ );
178 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
179 k = _table[key]; // Get hashed value
180 if( !k ) { // ?Miss?
181 NOT_PRODUCT( _lookup_misses++ );
182 key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel?
183 _table[key] = n; // Insert into table!
184 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
185 check_grow(); // Grow table if insert hit limit
186 return NULL; // Miss!
187 }
188 else if( first_sentinel == 0 && k == _sentinel ) {
189 first_sentinel = key; // Can insert here
190 }
191
192 }
193 ShouldNotReachHere();
194 return NULL;
195 }
196
197 //------------------------------hash_insert------------------------------------
198 // Insert into hash table
199 void NodeHash::hash_insert( Node *n ) {
200 // // "conflict" comments -- print nodes that conflict
201 // bool conflict = false;
202 // n->set_hash();
203 uint hash = n->hash();
204 if (hash == Node::NO_HASH) {
205 return;
206 }
207 check_grow();
208 uint key = hash & (_max-1);
209 uint stride = key | 0x01;
210
211 while( 1 ) { // While probing hash table
212 NOT_PRODUCT( _insert_probes++ );
213 Node *k = _table[key]; // Get hashed value
214 if( !k || (k == _sentinel) ) break; // Found a slot
215 assert( k != n, "already inserted" );
216 // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print(" conflict: "); k->dump(); conflict = true; }
217 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
218 }
219 _table[key] = n; // Insert into table!
220 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
221 // if( conflict ) { n->dump(); }
222 }
223
224 //------------------------------hash_delete------------------------------------
225 // Replace in hash table with sentinel
226 bool NodeHash::hash_delete( const Node *n ) {
227 Node *k;
228 uint hash = n->hash();
229 if (hash == Node::NO_HASH) {
230 NOT_PRODUCT( _delete_misses++ );
231 return false;
232 }
233 uint key = hash & (_max-1);
234 uint stride = key | 0x01;
235 debug_only( uint counter = 0; );
236 for( ; /* (k != NULL) && (k != _sentinel) */; ) {
237 debug_only( counter++ );
238 NOT_PRODUCT( _delete_probes++ );
239 k = _table[key]; // Get hashed value
240 if( !k ) { // Miss?
241 NOT_PRODUCT( _delete_misses++ );
242 #ifdef ASSERT
243 if( VerifyOpto ) {
244 for( uint i=0; i < _max; i++ )
245 assert( _table[i] != n, "changed edges with rehashing" );
246 }
247 #endif
248 return false; // Miss! Not in chain
249 }
250 else if( n == k ) {
251 NOT_PRODUCT( _delete_hits++ );
252 _table[key] = _sentinel; // Hit! Label as deleted entry
253 debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table.
254 return true;
255 }
256 else {
257 // collision: move through table with prime offset
258 key = (key + stride/*7*/) & (_max-1);
259 assert( counter <= _insert_limit, "Cycle in hash-table");
260 }
261 }
262 ShouldNotReachHere();
263 return false;
264 }
265
266 //------------------------------round_up---------------------------------------
267 // Round up to nearest power of 2
268 uint NodeHash::round_up( uint x ) {
269 x += (x>>2); // Add 25% slop
270 if( x <16 ) return 16; // Small stuff
271 uint i=16;
272 while( i < x ) i <<= 1; // Double to fit
273 return i; // Return hash table size
274 }
275
276 //------------------------------grow-------------------------------------------
277 // Grow _table to next power of 2 and insert old entries
278 void NodeHash::grow() {
279 // Record old state
280 uint old_max = _max;
281 Node **old_table = _table;
282 // Construct new table with twice the space
283 #ifndef PRODUCT
284 _grows++;
285 _total_inserts += _inserts;
286 _total_insert_probes += _insert_probes;
287 _insert_probes = 0;
288 #endif
289 _inserts = 0;
290 _max = _max << 1;
291 _table = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) );
292 memset(_table,0,sizeof(Node*)*_max);
293 _insert_limit = insert_limit();
294 // Insert old entries into the new table
295 for( uint i = 0; i < old_max; i++ ) {
296 Node *m = *old_table++;
297 if( !m || m == _sentinel ) continue;
298 debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table.
299 hash_insert(m);
300 }
301 }
302
303 //------------------------------clear------------------------------------------
304 // Clear all entries in _table to NULL but keep storage
305 void NodeHash::clear() {
306 #ifdef ASSERT
307 // Unlock all nodes upon removal from table.
308 for (uint i = 0; i < _max; i++) {
309 Node* n = _table[i];
310 if (!n || n == _sentinel) continue;
311 n->exit_hash_lock();
312 }
313 #endif
314
315 memset( _table, 0, _max * sizeof(Node*) );
316 }
317
318 //-----------------------remove_useless_nodes----------------------------------
319 // Remove useless nodes from value table,
320 // implementation does not depend on hash function
321 void NodeHash::remove_useless_nodes(VectorSet &useful) {
322
323 // Dead nodes in the hash table inherited from GVN should not replace
324 // existing nodes, remove dead nodes.
325 uint max = size();
326 Node *sentinel_node = sentinel();
327 for( uint i = 0; i < max; ++i ) {
328 Node *n = at(i);
329 if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) {
330 debug_only(n->exit_hash_lock()); // Unlock the node when removed
331 _table[i] = sentinel_node; // Replace with placeholder
332 }
333 }
334 }
335
336
337 void NodeHash::check_no_speculative_types() {
338 #ifdef ASSERT
339 uint max = size();
340 Node *sentinel_node = sentinel();
341 for (uint i = 0; i < max; ++i) {
342 Node *n = at(i);
343 if(n != NULL && n != sentinel_node && n->is_Type() && n->outcnt() > 0) {
344 TypeNode* tn = n->as_Type();
345 const Type* t = tn->type();
346 const Type* t_no_spec = t->remove_speculative();
347 assert(t == t_no_spec, "dead node in hash table or missed node during speculative cleanup");
348 }
349 }
350 #endif
351 }
352
353 #ifndef PRODUCT
354 //------------------------------dump-------------------------------------------
355 // Dump statistics for the hash table
356 void NodeHash::dump() {
357 _total_inserts += _inserts;
358 _total_insert_probes += _insert_probes;
359 if (PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0)) {
360 if (WizardMode) {
361 for (uint i=0; i<_max; i++) {
362 if (_table[i])
363 tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx);
364 }
365 }
366 tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max);
367 tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0);
368 tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses));
369 tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts);
370 // sentinels increase lookup cost, but not insert cost
371 assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function");
372 assert( _inserts+(_inserts>>3) < _max, "table too full" );
373 assert( _inserts*3+100 >= _insert_probes, "bad hash function" );
374 }
375 }
376
377 Node *NodeHash::find_index(uint idx) { // For debugging
378 // Find an entry by its index value
379 for( uint i = 0; i < _max; i++ ) {
380 Node *m = _table[i];
381 if( !m || m == _sentinel ) continue;
382 if( m->_idx == (uint)idx ) return m;
383 }
384 return NULL;
385 }
386 #endif
387
388 #ifdef ASSERT
389 NodeHash::~NodeHash() {
390 // Unlock all nodes upon destruction of table.
391 if (_table != (Node**)badAddress) clear();
392 }
393
394 void NodeHash::operator=(const NodeHash& nh) {
395 // Unlock all nodes upon replacement of table.
396 if (&nh == this) return;
397 if (_table != (Node**)badAddress) clear();
398 memcpy((void*)this, (void*)&nh, sizeof(*this));
399 // Do not increment hash_lock counts again.
400 // Instead, be sure we never again use the source table.
401 ((NodeHash*)&nh)->_table = (Node**)badAddress;
402 }
403
404
405 #endif
406
407
408 //=============================================================================
409 //------------------------------PhaseRemoveUseless-----------------------------
410 // 1) Use a breadthfirst walk to collect useful nodes reachable from root.
411 PhaseRemoveUseless::PhaseRemoveUseless(PhaseGVN *gvn, Unique_Node_List *worklist, PhaseNumber phase_num) : Phase(phase_num),
412 _useful(Thread::current()->resource_area()) {
413
414 // Implementation requires 'UseLoopSafepoints == true' and an edge from root
415 // to each SafePointNode at a backward branch. Inserted in add_safepoint().
416 if( !UseLoopSafepoints || !OptoRemoveUseless ) return;
417
418 // Identify nodes that are reachable from below, useful.
419 C->identify_useful_nodes(_useful);
420 // Update dead node list
421 C->update_dead_node_list(_useful);
422
423 // Remove all useless nodes from PhaseValues' recorded types
424 // Must be done before disconnecting nodes to preserve hash-table-invariant
425 gvn->remove_useless_nodes(_useful.member_set());
426
427 // Remove all useless nodes from future worklist
428 worklist->remove_useless_nodes(_useful.member_set());
429
430 // Disconnect 'useless' nodes that are adjacent to useful nodes
431 C->remove_useless_nodes(_useful);
432
433 // Remove edges from "root" to each SafePoint at a backward branch.
434 // They were inserted during parsing (see add_safepoint()) to make infinite
435 // loops without calls or exceptions visible to root, i.e., useful.
436 Node *root = C->root();
437 if( root != NULL ) {
438 for( uint i = root->req(); i < root->len(); ++i ) {
439 Node *n = root->in(i);
440 if( n != NULL && n->is_SafePoint() ) {
441 root->rm_prec(i);
442 --i;
443 }
444 }
445 }
446 }
447
448 //=============================================================================
449 //------------------------------PhaseRenumberLive------------------------------
450 // First, remove useless nodes (equivalent to identifying live nodes).
451 // Then, renumber live nodes.
452 //
453 // The set of live nodes is returned by PhaseRemoveUseless in the _useful structure.
454 // If the number of live nodes is 'x' (where 'x' == _useful.size()), then the
455 // PhaseRenumberLive updates the node ID of each node (the _idx field) with a unique
456 // value in the range [0, x).
457 //
458 // At the end of the PhaseRenumberLive phase, the compiler's count of unique nodes is
459 // updated to 'x' and the list of dead nodes is reset (as there are no dead nodes).
460 //
461 // The PhaseRenumberLive phase updates two data structures with the new node IDs.
462 // (1) The worklist is used by the PhaseIterGVN phase to identify nodes that must be
463 // processed. A new worklist (with the updated node IDs) is returned in 'new_worklist'.
464 // (2) Type information (the field PhaseGVN::_types) maps type information to each
465 // node ID. The mapping is updated to use the new node IDs as well. Updated type
466 // information is returned in PhaseGVN::_types.
467 //
468 // The PhaseRenumberLive phase does not preserve the order of elements in the worklist.
469 //
470 // Other data structures used by the compiler are not updated. The hash table for value
471 // numbering (the field PhaseGVN::_table) is not updated because computing the hash
472 // values is not based on node IDs. The field PhaseGVN::_nodes is not updated either
473 // because it is empty wherever PhaseRenumberLive is used.
474 PhaseRenumberLive::PhaseRenumberLive(PhaseGVN* gvn,
475 Unique_Node_List* worklist, Unique_Node_List* new_worklist,
476 PhaseNumber phase_num) :
477 PhaseRemoveUseless(gvn, worklist, Remove_Useless_And_Renumber_Live) {
478
479 assert(RenumberLiveNodes, "RenumberLiveNodes must be set to true for node renumbering to take place");
480 assert(C->live_nodes() == _useful.size(), "the number of live nodes must match the number of useful nodes");
481 assert(gvn->nodes_size() == 0, "GVN must not contain any nodes at this point");
482
483 uint old_unique_count = C->unique();
484 uint live_node_count = C->live_nodes();
485 uint worklist_size = worklist->size();
486
487 // Storage for the updated type information.
488 Type_Array new_type_array(C->comp_arena());
489
490 // Iterate over the set of live nodes.
491 uint current_idx = 0; // The current new node ID. Incremented after every assignment.
492 for (uint i = 0; i < _useful.size(); i++) {
493 Node* n = _useful.at(i);
494 // Sanity check that fails if we ever decide to execute this phase after EA
495 assert(!n->is_Phi() || n->as_Phi()->inst_mem_id() == -1, "should not be linked to data Phi");
496 const Type* type = gvn->type_or_null(n);
497 new_type_array.map(current_idx, type);
498
499 bool in_worklist = false;
500 if (worklist->member(n)) {
501 in_worklist = true;
502 }
503
504 n->set_idx(current_idx); // Update node ID.
505
506 if (in_worklist) {
507 new_worklist->push(n);
508 }
509
510 current_idx++;
511 }
512
513 assert(worklist_size == new_worklist->size(), "the new worklist must have the same size as the original worklist");
514 assert(live_node_count == current_idx, "all live nodes must be processed");
515
516 // Replace the compiler's type information with the updated type information.
517 gvn->replace_types(new_type_array);
518
519 // Update the unique node count of the compilation to the number of currently live nodes.
520 C->set_unique(live_node_count);
521
522 // Set the dead node count to 0 and reset dead node list.
523 C->reset_dead_node_list();
524 }
525
526
527 //=============================================================================
528 //------------------------------PhaseTransform---------------------------------
529 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
530 _arena(Thread::current()->resource_area()),
531 _nodes(_arena),
532 _types(_arena)
533 {
534 init_con_caches();
535 #ifndef PRODUCT
536 clear_progress();
537 clear_transforms();
538 set_allow_progress(true);
539 #endif
540 // Force allocation for currently existing nodes
541 _types.map(C->unique(), NULL);
542 }
543
544 //------------------------------PhaseTransform---------------------------------
545 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
546 _arena(arena),
547 _nodes(arena),
548 _types(arena)
549 {
550 init_con_caches();
551 #ifndef PRODUCT
552 clear_progress();
553 clear_transforms();
554 set_allow_progress(true);
555 #endif
556 // Force allocation for currently existing nodes
557 _types.map(C->unique(), NULL);
558 }
559
560 //------------------------------PhaseTransform---------------------------------
561 // Initialize with previously generated type information
562 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
563 _arena(pt->_arena),
564 _nodes(pt->_nodes),
565 _types(pt->_types)
566 {
567 init_con_caches();
568 #ifndef PRODUCT
569 clear_progress();
570 clear_transforms();
571 set_allow_progress(true);
572 #endif
573 }
574
575 void PhaseTransform::init_con_caches() {
576 memset(_icons,0,sizeof(_icons));
577 memset(_lcons,0,sizeof(_lcons));
578 memset(_zcons,0,sizeof(_zcons));
579 }
580
581
582 //--------------------------------find_int_type--------------------------------
583 const TypeInt* PhaseTransform::find_int_type(Node* n) {
584 if (n == NULL) return NULL;
585 // Call type_or_null(n) to determine node's type since we might be in
586 // parse phase and call n->Value() may return wrong type.
587 // (For example, a phi node at the beginning of loop parsing is not ready.)
588 const Type* t = type_or_null(n);
589 if (t == NULL) return NULL;
590 return t->isa_int();
591 }
592
593
594 //-------------------------------find_long_type--------------------------------
595 const TypeLong* PhaseTransform::find_long_type(Node* n) {
596 if (n == NULL) return NULL;
597 // (See comment above on type_or_null.)
598 const Type* t = type_or_null(n);
599 if (t == NULL) return NULL;
600 return t->isa_long();
601 }
602
603
604 #ifndef PRODUCT
605 void PhaseTransform::dump_old2new_map() const {
606 _nodes.dump();
607 }
608
609 void PhaseTransform::dump_new( uint nidx ) const {
610 for( uint i=0; i<_nodes.Size(); i++ )
611 if( _nodes[i] && _nodes[i]->_idx == nidx ) {
612 _nodes[i]->dump();
613 tty->cr();
614 tty->print_cr("Old index= %d",i);
615 return;
616 }
617 tty->print_cr("Node %d not found in the new indices", nidx);
618 }
619
620 //------------------------------dump_types-------------------------------------
621 void PhaseTransform::dump_types( ) const {
622 _types.dump();
623 }
624
625 //------------------------------dump_nodes_and_types---------------------------
626 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
627 VectorSet visited(Thread::current()->resource_area());
628 dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
629 }
630
631 //------------------------------dump_nodes_and_types_recur---------------------
632 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
633 if( !n ) return;
634 if( depth == 0 ) return;
635 if( visited.test_set(n->_idx) ) return;
636 for( uint i=0; i<n->len(); i++ ) {
637 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
638 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
639 }
640 n->dump();
641 if (type_or_null(n) != NULL) {
642 tty->print(" "); type(n)->dump(); tty->cr();
643 }
644 }
645
646 #endif
647
648
649 //=============================================================================
650 //------------------------------PhaseValues------------------------------------
651 // Set minimum table size to "255"
652 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
653 NOT_PRODUCT( clear_new_values(); )
654 }
655
656 //------------------------------PhaseValues------------------------------------
657 // Set minimum table size to "255"
658 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
659 _table(&ptv->_table) {
660 NOT_PRODUCT( clear_new_values(); )
661 }
662
663 //------------------------------PhaseValues------------------------------------
664 // Used by +VerifyOpto. Clear out hash table but copy _types array.
665 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
666 _table(ptv->arena(),ptv->_table.size()) {
667 NOT_PRODUCT( clear_new_values(); )
668 }
669
670 //------------------------------~PhaseValues-----------------------------------
671 #ifndef PRODUCT
672 PhaseValues::~PhaseValues() {
673 _table.dump();
674
675 // Statistics for value progress and efficiency
676 if( PrintCompilation && Verbose && WizardMode ) {
677 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
678 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values());
679 if( made_transforms() != 0 ) {
680 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() );
681 } else {
682 tty->cr();
683 }
684 }
685 }
686 #endif
687
688 //------------------------------makecon----------------------------------------
689 ConNode* PhaseTransform::makecon(const Type *t) {
690 assert(t->singleton(), "must be a constant");
691 assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
692 switch (t->base()) { // fast paths
693 case Type::Half:
694 case Type::Top: return (ConNode*) C->top();
695 case Type::Int: return intcon( t->is_int()->get_con() );
696 case Type::Long: return longcon( t->is_long()->get_con() );
697 default: break;
698 }
699 if (t->is_zero_type())
700 return zerocon(t->basic_type());
701 return uncached_makecon(t);
702 }
703
704 //--------------------------uncached_makecon-----------------------------------
705 // Make an idealized constant - one of ConINode, ConPNode, etc.
706 ConNode* PhaseValues::uncached_makecon(const Type *t) {
707 assert(t->singleton(), "must be a constant");
708 ConNode* x = ConNode::make(t);
709 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
710 if (k == NULL) {
711 set_type(x, t); // Missed, provide type mapping
712 GrowableArray<Node_Notes*>* nna = C->node_note_array();
713 if (nna != NULL) {
714 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
715 loc->clear(); // do not put debug info on constants
716 }
717 } else {
718 x->destruct(); // Hit, destroy duplicate constant
719 x = k; // use existing constant
720 }
721 return x;
722 }
723
724 //------------------------------intcon-----------------------------------------
725 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
726 ConINode* PhaseTransform::intcon(int i) {
727 // Small integer? Check cache! Check that cached node is not dead
728 if (i >= _icon_min && i <= _icon_max) {
729 ConINode* icon = _icons[i-_icon_min];
730 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
731 return icon;
732 }
733 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
734 assert(icon->is_Con(), "");
735 if (i >= _icon_min && i <= _icon_max)
736 _icons[i-_icon_min] = icon; // Cache small integers
737 return icon;
738 }
739
740 //------------------------------longcon----------------------------------------
741 // Fast long constant.
742 ConLNode* PhaseTransform::longcon(jlong l) {
743 // Small integer? Check cache! Check that cached node is not dead
744 if (l >= _lcon_min && l <= _lcon_max) {
745 ConLNode* lcon = _lcons[l-_lcon_min];
746 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
747 return lcon;
748 }
749 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
750 assert(lcon->is_Con(), "");
751 if (l >= _lcon_min && l <= _lcon_max)
752 _lcons[l-_lcon_min] = lcon; // Cache small integers
753 return lcon;
754 }
755
756 //------------------------------zerocon-----------------------------------------
757 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
758 ConNode* PhaseTransform::zerocon(BasicType bt) {
759 assert((uint)bt <= _zcon_max, "domain check");
760 ConNode* zcon = _zcons[bt];
761 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
762 return zcon;
763 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
764 _zcons[bt] = zcon;
765 return zcon;
766 }
767
768
769
770 //=============================================================================
771 //------------------------------transform--------------------------------------
772 // Return a node which computes the same function as this node, but in a
773 // faster or cheaper fashion.
774 Node *PhaseGVN::transform( Node *n ) {
775 return transform_no_reclaim(n);
776 }
777
778 //------------------------------transform--------------------------------------
779 // Return a node which computes the same function as this node, but
780 // in a faster or cheaper fashion.
781 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
782 NOT_PRODUCT( set_transforms(); )
783
784 // Apply the Ideal call in a loop until it no longer applies
785 Node *k = n;
786 NOT_PRODUCT( uint loop_count = 0; )
787 while( 1 ) {
788 Node *i = k->Ideal(this, /*can_reshape=*/false);
789 if( !i ) break;
790 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
791 k = i;
792 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
793 }
794 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
795
796
797 // If brand new node, make space in type array.
798 ensure_type_or_null(k);
799
800 // Since I just called 'Value' to compute the set of run-time values
801 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
802 // cache Value. Later requests for the local phase->type of this Node can
803 // use the cached Value instead of suffering with 'bottom_type'.
804 const Type *t = k->Value(this); // Get runtime Value set
805 assert(t != NULL, "value sanity");
806 if (type_or_null(k) != t) {
807 #ifndef PRODUCT
808 // Do not count initial visit to node as a transformation
809 if (type_or_null(k) == NULL) {
810 inc_new_values();
811 set_progress();
812 }
813 #endif
814 set_type(k, t);
815 // If k is a TypeNode, capture any more-precise type permanently into Node
816 k->raise_bottom_type(t);
817 }
818
819 if( t->singleton() && !k->is_Con() ) {
820 NOT_PRODUCT( set_progress(); )
821 return makecon(t); // Turn into a constant
822 }
823
824 // Now check for Identities
825 Node *i = k->Identity(this); // Look for a nearby replacement
826 if( i != k ) { // Found? Return replacement!
827 NOT_PRODUCT( set_progress(); )
828 return i;
829 }
830
831 // Global Value Numbering
832 i = hash_find_insert(k); // Insert if new
833 if( i && (i != k) ) {
834 // Return the pre-existing node
835 NOT_PRODUCT( set_progress(); )
836 return i;
837 }
838
839 // Return Idealized original
840 return k;
841 }
842
843 bool PhaseGVN::is_dominator_helper(Node *d, Node *n, bool linear_only) {
844 if (d->is_top() || n->is_top()) {
845 return false;
846 }
847 assert(d->is_CFG() && n->is_CFG(), "must have CFG nodes");
848 int i = 0;
849 while (d != n) {
850 n = IfNode::up_one_dom(n, linear_only);
851 i++;
852 if (n == NULL || i >= 10) {
853 return false;
854 }
855 }
856 return true;
857 }
858
859 #ifdef ASSERT
860 //------------------------------dead_loop_check--------------------------------
861 // Check for a simple dead loop when a data node references itself directly
862 // or through an other data node excluding cons and phis.
863 void PhaseGVN::dead_loop_check( Node *n ) {
864 // Phi may reference itself in a loop
865 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
866 // Do 2 levels check and only data inputs.
867 bool no_dead_loop = true;
868 uint cnt = n->req();
869 for (uint i = 1; i < cnt && no_dead_loop; i++) {
870 Node *in = n->in(i);
871 if (in == n) {
872 no_dead_loop = false;
873 } else if (in != NULL && !in->is_dead_loop_safe()) {
874 uint icnt = in->req();
875 for (uint j = 1; j < icnt && no_dead_loop; j++) {
876 if (in->in(j) == n || in->in(j) == in)
877 no_dead_loop = false;
878 }
879 }
880 }
881 if (!no_dead_loop) n->dump(3);
882 assert(no_dead_loop, "dead loop detected");
883 }
884 }
885 #endif
886
887 //=============================================================================
888 //------------------------------PhaseIterGVN-----------------------------------
889 // Initialize hash table to fresh and clean for +VerifyOpto
890 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ),
891 _stack(C->live_nodes() >> 1),
892 _delay_transform(false) {
893 }
894
895 //------------------------------PhaseIterGVN-----------------------------------
896 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
897 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
898 _worklist( igvn->_worklist ),
899 _stack( igvn->_stack ),
900 _delay_transform(igvn->_delay_transform)
901 {
902 }
903
904 //------------------------------PhaseIterGVN-----------------------------------
905 // Initialize with previous PhaseGVN info from Parser
906 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
907 _worklist(*C->for_igvn()),
908 // TODO: Before incremental inlining it was allocated only once and it was fine. Now that
909 // the constructor is used in incremental inlining, this consumes too much memory:
910 // _stack(C->live_nodes() >> 1),
911 // So, as a band-aid, we replace this by:
912 _stack(C->comp_arena(), 32),
913 _delay_transform(false)
914 {
915 uint max;
916
917 // Dead nodes in the hash table inherited from GVN were not treated as
918 // roots during def-use info creation; hence they represent an invisible
919 // use. Clear them out.
920 max = _table.size();
921 for( uint i = 0; i < max; ++i ) {
922 Node *n = _table.at(i);
923 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
924 if( n->is_top() ) continue;
925 assert( false, "Parse::remove_useless_nodes missed this node");
926 hash_delete(n);
927 }
928 }
929
930 // Any Phis or Regions on the worklist probably had uses that could not
931 // make more progress because the uses were made while the Phis and Regions
932 // were in half-built states. Put all uses of Phis and Regions on worklist.
933 max = _worklist.size();
934 for( uint j = 0; j < max; j++ ) {
935 Node *n = _worklist.at(j);
936 uint uop = n->Opcode();
937 if( uop == Op_Phi || uop == Op_Region ||
938 n->is_Type() ||
939 n->is_Mem() )
940 add_users_to_worklist(n);
941 }
942 }
943
944 /**
945 * Initialize worklist for each node.
946 */
947 void PhaseIterGVN::init_worklist(Node* first) {
948 Unique_Node_List to_process;
949 to_process.push(first);
950
951 while (to_process.size() > 0) {
952 Node* n = to_process.pop();
953 if (!_worklist.member(n)) {
954 _worklist.push(n);
955
956 uint cnt = n->req();
957 for(uint i = 0; i < cnt; i++) {
958 Node* m = n->in(i);
959 if (m != NULL) {
960 to_process.push(m);
961 }
962 }
963 }
964 }
965 }
966
967 #ifndef PRODUCT
968 void PhaseIterGVN::verify_step(Node* n) {
969 if (VerifyIterativeGVN) {
970 _verify_window[_verify_counter % _verify_window_size] = n;
971 ++_verify_counter;
972 ResourceMark rm;
973 ResourceArea* area = Thread::current()->resource_area();
974 VectorSet old_space(area), new_space(area);
975 if (C->unique() < 1000 ||
976 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
977 ++_verify_full_passes;
978 Node::verify_recur(C->root(), -1, old_space, new_space);
979 }
980 const int verify_depth = 4;
981 for ( int i = 0; i < _verify_window_size; i++ ) {
982 Node* n = _verify_window[i];
983 if ( n == NULL ) continue;
984 if( n->in(0) == NodeSentinel ) { // xform_idom
985 _verify_window[i] = n->in(1);
986 --i; continue;
987 }
988 // Typical fanout is 1-2, so this call visits about 6 nodes.
989 Node::verify_recur(n, verify_depth, old_space, new_space);
990 }
991 }
992 }
993
994 void PhaseIterGVN::trace_PhaseIterGVN(Node* n, Node* nn, const Type* oldtype) {
995 if (TraceIterativeGVN) {
996 uint wlsize = _worklist.size();
997 const Type* newtype = type_or_null(n);
998 if (nn != n) {
999 // print old node
1000 tty->print("< ");
1001 if (oldtype != newtype && oldtype != NULL) {
1002 oldtype->dump();
1003 }
1004 do { tty->print("\t"); } while (tty->position() < 16);
1005 tty->print("<");
1006 n->dump();
1007 }
1008 if (oldtype != newtype || nn != n) {
1009 // print new node and/or new type
1010 if (oldtype == NULL) {
1011 tty->print("* ");
1012 } else if (nn != n) {
1013 tty->print("> ");
1014 } else {
1015 tty->print("= ");
1016 }
1017 if (newtype == NULL) {
1018 tty->print("null");
1019 } else {
1020 newtype->dump();
1021 }
1022 do { tty->print("\t"); } while (tty->position() < 16);
1023 nn->dump();
1024 }
1025 if (Verbose && wlsize < _worklist.size()) {
1026 tty->print(" Push {");
1027 while (wlsize != _worklist.size()) {
1028 Node* pushed = _worklist.at(wlsize++);
1029 tty->print(" %d", pushed->_idx);
1030 }
1031 tty->print_cr(" }");
1032 }
1033 if (nn != n) {
1034 // ignore n, it might be subsumed
1035 verify_step((Node*) NULL);
1036 }
1037 }
1038 }
1039
1040 void PhaseIterGVN::init_verifyPhaseIterGVN() {
1041 _verify_counter = 0;
1042 _verify_full_passes = 0;
1043 for (int i = 0; i < _verify_window_size; i++) {
1044 _verify_window[i] = NULL;
1045 }
1046 #ifdef ASSERT
1047 // Verify that all modified nodes are on _worklist
1048 Unique_Node_List* modified_list = C->modified_nodes();
1049 while (modified_list != NULL && modified_list->size()) {
1050 Node* n = modified_list->pop();
1051 if (n->outcnt() != 0 && !n->is_Con() && !_worklist.member(n)) {
1052 n->dump();
1053 assert(false, "modified node is not on IGVN._worklist");
1054 }
1055 }
1056 #endif
1057 }
1058
1059 void PhaseIterGVN::verify_PhaseIterGVN() {
1060 #ifdef ASSERT
1061 // Verify nodes with changed inputs.
1062 Unique_Node_List* modified_list = C->modified_nodes();
1063 while (modified_list != NULL && modified_list->size()) {
1064 Node* n = modified_list->pop();
1065 if (n->outcnt() != 0 && !n->is_Con()) { // skip dead and Con nodes
1066 n->dump();
1067 assert(false, "modified node was not processed by IGVN.transform_old()");
1068 }
1069 }
1070 #endif
1071
1072 C->verify_graph_edges();
1073 if( VerifyOpto && allow_progress() ) {
1074 // Must turn off allow_progress to enable assert and break recursion
1075 C->root()->verify();
1076 { // Check if any progress was missed using IterGVN
1077 // Def-Use info enables transformations not attempted in wash-pass
1078 // e.g. Region/Phi cleanup, ...
1079 // Null-check elision -- may not have reached fixpoint
1080 // do not propagate to dominated nodes
1081 ResourceMark rm;
1082 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
1083 // Fill worklist completely
1084 igvn2.init_worklist(C->root());
1085
1086 igvn2.set_allow_progress(false);
1087 igvn2.optimize();
1088 igvn2.set_allow_progress(true);
1089 }
1090 }
1091 if (VerifyIterativeGVN && PrintOpto) {
1092 if (_verify_counter == _verify_full_passes) {
1093 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
1094 (int) _verify_full_passes);
1095 } else {
1096 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
1097 (int) _verify_counter, (int) _verify_full_passes);
1098 }
1099 }
1100
1101 #ifdef ASSERT
1102 while (modified_list->size()) {
1103 Node* n = modified_list->pop();
1104 n->dump();
1105 assert(false, "VerifyIterativeGVN: new modified node was added");
1106 }
1107 #endif
1108 }
1109 #endif /* PRODUCT */
1110
1111 #ifdef ASSERT
1112 /**
1113 * Dumps information that can help to debug the problem. A debug
1114 * build fails with an assert.
1115 */
1116 void PhaseIterGVN::dump_infinite_loop_info(Node* n) {
1117 n->dump(4);
1118 _worklist.dump();
1119 assert(false, "infinite loop in PhaseIterGVN::optimize");
1120 }
1121
1122 /**
1123 * Prints out information about IGVN if the 'verbose' option is used.
1124 */
1125 void PhaseIterGVN::trace_PhaseIterGVN_verbose(Node* n, int num_processed) {
1126 if (TraceIterativeGVN && Verbose) {
1127 tty->print(" Pop ");
1128 n->dump();
1129 if ((num_processed % 100) == 0) {
1130 _worklist.print_set();
1131 }
1132 }
1133 }
1134 #endif /* ASSERT */
1135
1136 void PhaseIterGVN::optimize() {
1137 DEBUG_ONLY(uint num_processed = 0;)
1138 NOT_PRODUCT(init_verifyPhaseIterGVN();)
1139
1140 uint loop_count = 0;
1141 // Pull from worklist and transform the node. If the node has changed,
1142 // update edge info and put uses on worklist.
1143 while(_worklist.size()) {
1144 if (C->check_node_count(NodeLimitFudgeFactor * 2, "Out of nodes")) {
1145 return;
1146 }
1147 Node* n = _worklist.pop();
1148 if (++loop_count >= K * C->live_nodes()) {
1149 DEBUG_ONLY(dump_infinite_loop_info(n);)
1150 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
1151 return;
1152 }
1153 DEBUG_ONLY(trace_PhaseIterGVN_verbose(n, num_processed++);)
1154 if (n->outcnt() != 0) {
1155 NOT_PRODUCT(const Type* oldtype = type_or_null(n));
1156 // Do the transformation
1157 Node* nn = transform_old(n);
1158 NOT_PRODUCT(trace_PhaseIterGVN(n, nn, oldtype);)
1159 } else if (!n->is_top()) {
1160 remove_dead_node(n);
1161 }
1162 }
1163 NOT_PRODUCT(verify_PhaseIterGVN();)
1164 }
1165
1166
1167 /**
1168 * Register a new node with the optimizer. Update the types array, the def-use
1169 * info. Put on worklist.
1170 */
1171 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
1172 set_type_bottom(n);
1173 _worklist.push(n);
1174 if (orig != NULL) C->copy_node_notes_to(n, orig);
1175 return n;
1176 }
1177
1178 //------------------------------transform--------------------------------------
1179 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
1180 Node *PhaseIterGVN::transform( Node *n ) {
1181 if (_delay_transform) {
1182 // Register the node but don't optimize for now
1183 register_new_node_with_optimizer(n);
1184 return n;
1185 }
1186
1187 // If brand new node, make space in type array, and give it a type.
1188 ensure_type_or_null(n);
1189 if (type_or_null(n) == NULL) {
1190 set_type_bottom(n);
1191 }
1192
1193 return transform_old(n);
1194 }
1195
1196 Node *PhaseIterGVN::transform_old(Node* n) {
1197 DEBUG_ONLY(uint loop_count = 0;);
1198 NOT_PRODUCT(set_transforms());
1199
1200 // Remove 'n' from hash table in case it gets modified
1201 _table.hash_delete(n);
1202 if (VerifyIterativeGVN) {
1203 assert(!_table.find_index(n->_idx), "found duplicate entry in table");
1204 }
1205
1206 // Apply the Ideal call in a loop until it no longer applies
1207 Node* k = n;
1208 DEBUG_ONLY(dead_loop_check(k);)
1209 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1210 C->remove_modified_node(k);
1211 Node* i = k->Ideal(this, /*can_reshape=*/true);
1212 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1213 #ifndef PRODUCT
1214 verify_step(k);
1215 if (i && VerifyOpto ) {
1216 if (!allow_progress()) {
1217 if (i->is_Add() && (i->outcnt() == 1)) {
1218 // Switched input to left side because this is the only use
1219 } else if (i->is_If() && (i->in(0) == NULL)) {
1220 // This IF is dead because it is dominated by an equivalent IF When
1221 // dominating if changed, info is not propagated sparsely to 'this'
1222 // Propagating this info further will spuriously identify other
1223 // progress.
1224 return i;
1225 } else
1226 set_progress();
1227 } else {
1228 set_progress();
1229 }
1230 }
1231 #endif
1232
1233 while (i != NULL) {
1234 #ifdef ASSERT
1235 if (loop_count >= K) {
1236 dump_infinite_loop_info(i);
1237 }
1238 loop_count++;
1239 #endif
1240 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1241 // Made a change; put users of original Node on worklist
1242 add_users_to_worklist(k);
1243 // Replacing root of transform tree?
1244 if (k != i) {
1245 // Make users of old Node now use new.
1246 subsume_node(k, i);
1247 k = i;
1248 }
1249 DEBUG_ONLY(dead_loop_check(k);)
1250 // Try idealizing again
1251 DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1252 C->remove_modified_node(k);
1253 i = k->Ideal(this, /*can_reshape=*/true);
1254 assert(i != k || is_new || (i->outcnt() > 0), "don't return dead nodes");
1255 #ifndef PRODUCT
1256 verify_step(k);
1257 if (i && VerifyOpto) {
1258 set_progress();
1259 }
1260 #endif
1261 }
1262
1263 // If brand new node, make space in type array.
1264 ensure_type_or_null(k);
1265
1266 // See what kind of values 'k' takes on at runtime
1267 const Type* t = k->Value(this);
1268 assert(t != NULL, "value sanity");
1269
1270 // Since I just called 'Value' to compute the set of run-time values
1271 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1272 // cache Value. Later requests for the local phase->type of this Node can
1273 // use the cached Value instead of suffering with 'bottom_type'.
1274 if (type_or_null(k) != t) {
1275 #ifndef PRODUCT
1276 inc_new_values();
1277 set_progress();
1278 #endif
1279 set_type(k, t);
1280 // If k is a TypeNode, capture any more-precise type permanently into Node
1281 k->raise_bottom_type(t);
1282 // Move users of node to worklist
1283 add_users_to_worklist(k);
1284 }
1285 // If 'k' computes a constant, replace it with a constant
1286 if (t->singleton() && !k->is_Con()) {
1287 NOT_PRODUCT(set_progress();)
1288 Node* con = makecon(t); // Make a constant
1289 add_users_to_worklist(k);
1290 subsume_node(k, con); // Everybody using k now uses con
1291 return con;
1292 }
1293
1294 // Now check for Identities
1295 i = k->Identity(this); // Look for a nearby replacement
1296 if (i != k) { // Found? Return replacement!
1297 NOT_PRODUCT(set_progress();)
1298 add_users_to_worklist(k);
1299 subsume_node(k, i); // Everybody using k now uses i
1300 return i;
1301 }
1302
1303 // Global Value Numbering
1304 i = hash_find_insert(k); // Check for pre-existing node
1305 if (i && (i != k)) {
1306 // Return the pre-existing node if it isn't dead
1307 NOT_PRODUCT(set_progress();)
1308 add_users_to_worklist(k);
1309 subsume_node(k, i); // Everybody using k now uses i
1310 return i;
1311 }
1312
1313 // Return Idealized original
1314 return k;
1315 }
1316
1317 //---------------------------------saturate------------------------------------
1318 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1319 const Type* limit_type) const {
1320 return new_type->narrow(old_type);
1321 }
1322
1323 //------------------------------remove_globally_dead_node----------------------
1324 // Kill a globally dead Node. All uses are also globally dead and are
1325 // aggressively trimmed.
1326 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1327 enum DeleteProgress {
1328 PROCESS_INPUTS,
1329 PROCESS_OUTPUTS
1330 };
1331 assert(_stack.is_empty(), "not empty");
1332 _stack.push(dead, PROCESS_INPUTS);
1333
1334 while (_stack.is_nonempty()) {
1335 dead = _stack.node();
1336 uint progress_state = _stack.index();
1337 assert(dead != C->root(), "killing root, eh?");
1338 assert(!dead->is_top(), "add check for top when pushing");
1339 NOT_PRODUCT( set_progress(); )
1340 if (progress_state == PROCESS_INPUTS) {
1341 // After following inputs, continue to outputs
1342 _stack.set_index(PROCESS_OUTPUTS);
1343 if (!dead->is_Con()) { // Don't kill cons but uses
1344 bool recurse = false;
1345 // Remove from hash table
1346 _table.hash_delete( dead );
1347 // Smash all inputs to 'dead', isolating him completely
1348 for (uint i = 0; i < dead->req(); i++) {
1349 Node *in = dead->in(i);
1350 if (in != NULL && in != C->top()) { // Points to something?
1351 int nrep = dead->replace_edge(in, NULL); // Kill edges
1352 assert((nrep > 0), "sanity");
1353 if (in->outcnt() == 0) { // Made input go dead?
1354 _stack.push(in, PROCESS_INPUTS); // Recursively remove
1355 recurse = true;
1356 } else if (in->outcnt() == 1 &&
1357 in->has_special_unique_user()) {
1358 _worklist.push(in->unique_out());
1359 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1360 if (in->Opcode() == Op_Region) {
1361 _worklist.push(in);
1362 } else if (in->is_Store()) {
1363 DUIterator_Fast imax, i = in->fast_outs(imax);
1364 _worklist.push(in->fast_out(i));
1365 i++;
1366 if (in->outcnt() == 2) {
1367 _worklist.push(in->fast_out(i));
1368 i++;
1369 }
1370 assert(!(i < imax), "sanity");
1371 }
1372 }
1373 if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory &&
1374 in->is_Proj() && in->in(0) != NULL && in->in(0)->is_Initialize()) {
1375 // A Load that directly follows an InitializeNode is
1376 // going away. The Stores that follow are candidates
1377 // again to be captured by the InitializeNode.
1378 for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) {
1379 Node *n = in->fast_out(j);
1380 if (n->is_Store()) {
1381 _worklist.push(n);
1382 }
1383 }
1384 }
1385 } // if (in != NULL && in != C->top())
1386 } // for (uint i = 0; i < dead->req(); i++)
1387 if (recurse) {
1388 continue;
1389 }
1390 } // if (!dead->is_Con())
1391 } // if (progress_state == PROCESS_INPUTS)
1392
1393 // Aggressively kill globally dead uses
1394 // (Rather than pushing all the outs at once, we push one at a time,
1395 // plus the parent to resume later, because of the indefinite number
1396 // of edge deletions per loop trip.)
1397 if (dead->outcnt() > 0) {
1398 // Recursively remove output edges
1399 _stack.push(dead->raw_out(0), PROCESS_INPUTS);
1400 } else {
1401 // Finished disconnecting all input and output edges.
1402 _stack.pop();
1403 // Remove dead node from iterative worklist
1404 _worklist.remove(dead);
1405 C->remove_modified_node(dead);
1406 // Constant node that has no out-edges and has only one in-edge from
1407 // root is usually dead. However, sometimes reshaping walk makes
1408 // it reachable by adding use edges. So, we will NOT count Con nodes
1409 // as dead to be conservative about the dead node count at any
1410 // given time.
1411 if (!dead->is_Con()) {
1412 C->record_dead_node(dead->_idx);
1413 }
1414 if (dead->is_macro()) {
1415 C->remove_macro_node(dead);
1416 }
1417 if (dead->is_expensive()) {
1418 C->remove_expensive_node(dead);
1419 }
1420 CastIINode* cast = dead->isa_CastII();
1421 if (cast != NULL && cast->has_range_check()) {
1422 C->remove_range_check_cast(cast);
1423 }
1424 if (dead->is_ValueTypePtr()) {
1425 C->remove_value_type_ptr(dead->as_ValueTypePtr());
1426 }
1427 }
1428 } // while (_stack.is_nonempty())
1429 }
1430
1431 //------------------------------subsume_node-----------------------------------
1432 // Remove users from node 'old' and add them to node 'nn'.
1433 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1434 assert( old != hash_find(old), "should already been removed" );
1435 assert( old != C->top(), "cannot subsume top node");
1436 // Copy debug or profile information to the new version:
1437 C->copy_node_notes_to(nn, old);
1438 // Move users of node 'old' to node 'nn'
1439 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1440 Node* use = old->last_out(i); // for each use...
1441 // use might need re-hashing (but it won't if it's a new node)
1442 rehash_node_delayed(use);
1443 // Update use-def info as well
1444 // We remove all occurrences of old within use->in,
1445 // so as to avoid rehashing any node more than once.
1446 // The hash table probe swamps any outer loop overhead.
1447 uint num_edges = 0;
1448 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1449 if (use->in(j) == old) {
1450 use->set_req(j, nn);
1451 ++num_edges;
1452 }
1453 }
1454 i -= num_edges; // we deleted 1 or more copies of this edge
1455 }
1456
1457 // Search for instance field data PhiNodes in the same region pointing to the old
1458 // memory PhiNode and update their instance memory ids to point to the new node.
1459 if (old->is_Phi() && old->as_Phi()->type()->has_memory() && old->in(0) != NULL) {
1460 Node* region = old->in(0);
1461 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1462 PhiNode* phi = region->fast_out(i)->isa_Phi();
1463 if (phi != NULL && phi->inst_mem_id() == (int)old->_idx) {
1464 phi->set_inst_mem_id((int)nn->_idx);
1465 }
1466 }
1467 }
1468
1469 // Smash all inputs to 'old', isolating him completely
1470 Node *temp = new Node(1);
1471 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1472 remove_dead_node( old );
1473 temp->del_req(0); // Yank bogus edge
1474 #ifndef PRODUCT
1475 if( VerifyIterativeGVN ) {
1476 for ( int i = 0; i < _verify_window_size; i++ ) {
1477 if ( _verify_window[i] == old )
1478 _verify_window[i] = nn;
1479 }
1480 }
1481 #endif
1482 _worklist.remove(temp); // this can be necessary
1483 temp->destruct(); // reuse the _idx of this little guy
1484 }
1485
1486 void PhaseIterGVN::replace_in_uses(Node* n, Node* m) {
1487 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1488 Node* u = n->fast_out(i);
1489 if (u != n) {
1490 rehash_node_delayed(u);
1491 int nb = u->replace_edge(n, m);
1492 --i, imax -= nb;
1493 }
1494 }
1495 }
1496
1497 //------------------------------add_users_to_worklist--------------------------
1498 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1499 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1500 _worklist.push(n->fast_out(i)); // Push on worklist
1501 }
1502 }
1503
1504 // Return counted loop Phi if as a counted loop exit condition, cmp
1505 // compares the the induction variable with n
1506 static PhiNode* countedloop_phi_from_cmp(CmpINode* cmp, Node* n) {
1507 for (DUIterator_Fast imax, i = cmp->fast_outs(imax); i < imax; i++) {
1508 Node* bol = cmp->fast_out(i);
1509 for (DUIterator_Fast i2max, i2 = bol->fast_outs(i2max); i2 < i2max; i2++) {
1510 Node* iff = bol->fast_out(i2);
1511 if (iff->is_CountedLoopEnd()) {
1512 CountedLoopEndNode* cle = iff->as_CountedLoopEnd();
1513 if (cle->limit() == n) {
1514 PhiNode* phi = cle->phi();
1515 if (phi != NULL) {
1516 return phi;
1517 }
1518 }
1519 }
1520 }
1521 }
1522 return NULL;
1523 }
1524
1525 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1526 add_users_to_worklist0(n);
1527
1528 // Move users of node to worklist
1529 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1530 Node* use = n->fast_out(i); // Get use
1531
1532 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1533 use->is_Store() ) // Enable store/load same address
1534 add_users_to_worklist0(use);
1535
1536 // If we changed the receiver type to a call, we need to revisit
1537 // the Catch following the call. It's looking for a non-NULL
1538 // receiver to know when to enable the regular fall-through path
1539 // in addition to the NullPtrException path.
1540 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1541 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control);
1542 if (p != NULL) {
1543 add_users_to_worklist0(p);
1544 }
1545 }
1546
1547 uint use_op = use->Opcode();
1548 if(use->is_Cmp()) { // Enable CMP/BOOL optimization
1549 add_users_to_worklist(use); // Put Bool on worklist
1550 if (use->outcnt() > 0) {
1551 Node* bol = use->raw_out(0);
1552 if (bol->outcnt() > 0) {
1553 Node* iff = bol->raw_out(0);
1554 if (iff->outcnt() == 2) {
1555 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1556 // phi merging either 0 or 1 onto the worklist
1557 Node* ifproj0 = iff->raw_out(0);
1558 Node* ifproj1 = iff->raw_out(1);
1559 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1560 Node* region0 = ifproj0->raw_out(0);
1561 Node* region1 = ifproj1->raw_out(0);
1562 if( region0 == region1 )
1563 add_users_to_worklist0(region0);
1564 }
1565 }
1566 }
1567 }
1568 if (use_op == Op_CmpI) {
1569 Node* phi = countedloop_phi_from_cmp((CmpINode*)use, n);
1570 if (phi != NULL) {
1571 // If an opaque node feeds into the limit condition of a
1572 // CountedLoop, we need to process the Phi node for the
1573 // induction variable when the opaque node is removed:
1574 // the range of values taken by the Phi is now known and
1575 // so its type is also known.
1576 _worklist.push(phi);
1577 }
1578 Node* in1 = use->in(1);
1579 for (uint i = 0; i < in1->outcnt(); i++) {
1580 if (in1->raw_out(i)->Opcode() == Op_CastII) {
1581 Node* castii = in1->raw_out(i);
1582 if (castii->in(0) != NULL && castii->in(0)->in(0) != NULL && castii->in(0)->in(0)->is_If()) {
1583 Node* ifnode = castii->in(0)->in(0);
1584 if (ifnode->in(1) != NULL && ifnode->in(1)->is_Bool() && ifnode->in(1)->in(1) == use) {
1585 // Reprocess a CastII node that may depend on an
1586 // opaque node value when the opaque node is
1587 // removed. In case it carries a dependency we can do
1588 // a better job of computing its type.
1589 _worklist.push(castii);
1590 }
1591 }
1592 }
1593 }
1594 }
1595 }
1596
1597 // If changed Cast input, check Phi users for simple cycles
1598 if (use->is_ConstraintCast()) {
1599 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1600 Node* u = use->fast_out(i2);
1601 if (u->is_Phi())
1602 _worklist.push(u);
1603 }
1604 }
1605 // If changed LShift inputs, check RShift users for useless sign-ext
1606 if( use_op == Op_LShiftI ) {
1607 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1608 Node* u = use->fast_out(i2);
1609 if (u->Opcode() == Op_RShiftI)
1610 _worklist.push(u);
1611 }
1612 }
1613 // If changed AddI/SubI inputs, check CmpU for range check optimization.
1614 if (use_op == Op_AddI || use_op == Op_SubI) {
1615 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1616 Node* u = use->fast_out(i2);
1617 if (u->is_Cmp() && (u->Opcode() == Op_CmpU)) {
1618 _worklist.push(u);
1619 }
1620 }
1621 }
1622 // If changed AddP inputs, check Stores for loop invariant
1623 if( use_op == Op_AddP ) {
1624 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1625 Node* u = use->fast_out(i2);
1626 if (u->is_Mem())
1627 _worklist.push(u);
1628 }
1629 }
1630 // If changed initialization activity, check dependent Stores
1631 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1632 InitializeNode* init = use->as_Allocate()->initialization();
1633 if (init != NULL) {
1634 Node* imem = init->proj_out(TypeFunc::Memory);
1635 if (imem != NULL) add_users_to_worklist0(imem);
1636 }
1637 }
1638 if (use_op == Op_Initialize) {
1639 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory);
1640 if (imem != NULL) add_users_to_worklist0(imem);
1641 }
1642 if (use_op == Op_CastP2X) {
1643 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1644 Node* u = use->fast_out(i2);
1645 if (u->Opcode() == Op_AndX) {
1646 _worklist.push(u);
1647 }
1648 }
1649 }
1650 }
1651 }
1652
1653 /**
1654 * Remove the speculative part of all types that we know of
1655 */
1656 void PhaseIterGVN::remove_speculative_types() {
1657 assert(UseTypeSpeculation, "speculation is off");
1658 for (uint i = 0; i < _types.Size(); i++) {
1659 const Type* t = _types.fast_lookup(i);
1660 if (t != NULL) {
1661 _types.map(i, t->remove_speculative());
1662 }
1663 }
1664 _table.check_no_speculative_types();
1665 }
1666
1667 //=============================================================================
1668 #ifndef PRODUCT
1669 uint PhaseCCP::_total_invokes = 0;
1670 uint PhaseCCP::_total_constants = 0;
1671 #endif
1672 //------------------------------PhaseCCP---------------------------------------
1673 // Conditional Constant Propagation, ala Wegman & Zadeck
1674 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1675 NOT_PRODUCT( clear_constants(); )
1676 assert( _worklist.size() == 0, "" );
1677 // Clear out _nodes from IterGVN. Must be clear to transform call.
1678 _nodes.clear(); // Clear out from IterGVN
1679 analyze();
1680 }
1681
1682 #ifndef PRODUCT
1683 //------------------------------~PhaseCCP--------------------------------------
1684 PhaseCCP::~PhaseCCP() {
1685 inc_invokes();
1686 _total_constants += count_constants();
1687 }
1688 #endif
1689
1690
1691 #ifdef ASSERT
1692 static bool ccp_type_widens(const Type* t, const Type* t0) {
1693 assert(t->meet(t0) == t, "Not monotonic");
1694 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1695 case Type::Int:
1696 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1697 break;
1698 case Type::Long:
1699 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1700 break;
1701 default:
1702 break;
1703 }
1704 return true;
1705 }
1706 #endif //ASSERT
1707
1708 //------------------------------analyze----------------------------------------
1709 void PhaseCCP::analyze() {
1710 // Initialize all types to TOP, optimistic analysis
1711 for (int i = C->unique() - 1; i >= 0; i--) {
1712 _types.map(i,Type::TOP);
1713 }
1714
1715 // Push root onto worklist
1716 Unique_Node_List worklist;
1717 worklist.push(C->root());
1718
1719 // Pull from worklist; compute new value; push changes out.
1720 // This loop is the meat of CCP.
1721 while( worklist.size() ) {
1722 Node *n = worklist.pop();
1723 const Type *t = n->Value(this);
1724 if (t != type(n)) {
1725 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1726 #ifndef PRODUCT
1727 if( TracePhaseCCP ) {
1728 t->dump();
1729 do { tty->print("\t"); } while (tty->position() < 16);
1730 n->dump();
1731 }
1732 #endif
1733 set_type(n, t);
1734 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1735 Node* m = n->fast_out(i); // Get user
1736 if (m->is_Region()) { // New path to Region? Must recheck Phis too
1737 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1738 Node* p = m->fast_out(i2); // Propagate changes to uses
1739 if (p->bottom_type() != type(p)) { // If not already bottomed out
1740 worklist.push(p); // Propagate change to user
1741 }
1742 }
1743 }
1744 // If we changed the receiver type to a call, we need to revisit
1745 // the Catch following the call. It's looking for a non-NULL
1746 // receiver to know when to enable the regular fall-through path
1747 // in addition to the NullPtrException path
1748 if (m->is_Call()) {
1749 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1750 Node* p = m->fast_out(i2); // Propagate changes to uses
1751 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1) {
1752 worklist.push(p->unique_out());
1753 }
1754 }
1755 }
1756 if (m->bottom_type() != type(m)) { // If not already bottomed out
1757 worklist.push(m); // Propagate change to user
1758 }
1759
1760 // CmpU nodes can get their type information from two nodes up in the
1761 // graph (instead of from the nodes immediately above). Make sure they
1762 // are added to the worklist if nodes they depend on are updated, since
1763 // they could be missed and get wrong types otherwise.
1764 uint m_op = m->Opcode();
1765 if (m_op == Op_AddI || m_op == Op_SubI) {
1766 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1767 Node* p = m->fast_out(i2); // Propagate changes to uses
1768 if (p->Opcode() == Op_CmpU) {
1769 // Got a CmpU which might need the new type information from node n.
1770 if(p->bottom_type() != type(p)) { // If not already bottomed out
1771 worklist.push(p); // Propagate change to user
1772 }
1773 }
1774 }
1775 }
1776 // If n is used in a counted loop exit condition then the type
1777 // of the counted loop's Phi depends on the type of n. See
1778 // PhiNode::Value().
1779 if (m_op == Op_CmpI) {
1780 PhiNode* phi = countedloop_phi_from_cmp((CmpINode*)m, n);
1781 if (phi != NULL) {
1782 worklist.push(phi);
1783 }
1784 }
1785 if (m_op == Op_CastP2X) {
1786 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1787 Node* u = m->fast_out(i2);
1788 if (u->Opcode() == Op_AndX) {
1789 worklist.push(u);
1790 }
1791 }
1792 }
1793 }
1794 }
1795 }
1796 }
1797
1798 //------------------------------do_transform-----------------------------------
1799 // Top level driver for the recursive transformer
1800 void PhaseCCP::do_transform() {
1801 // Correct leaves of new-space Nodes; they point to old-space.
1802 C->set_root( transform(C->root())->as_Root() );
1803 assert( C->top(), "missing TOP node" );
1804 assert( C->root(), "missing root" );
1805 }
1806
1807 //------------------------------transform--------------------------------------
1808 // Given a Node in old-space, clone him into new-space.
1809 // Convert any of his old-space children into new-space children.
1810 Node *PhaseCCP::transform( Node *n ) {
1811 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1812 if( new_node != NULL )
1813 return new_node; // Been there, done that, return old answer
1814 new_node = transform_once(n); // Check for constant
1815 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1816
1817 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1818 GrowableArray <Node *> trstack(C->live_nodes() >> 1);
1819
1820 trstack.push(new_node); // Process children of cloned node
1821 while ( trstack.is_nonempty() ) {
1822 Node *clone = trstack.pop();
1823 uint cnt = clone->req();
1824 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1825 Node *input = clone->in(i);
1826 if( input != NULL ) { // Ignore NULLs
1827 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1828 if( new_input == NULL ) {
1829 new_input = transform_once(input); // Check for constant
1830 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1831 trstack.push(new_input);
1832 }
1833 assert( new_input == clone->in(i), "insanity check");
1834 }
1835 }
1836 }
1837 return new_node;
1838 }
1839
1840
1841 //------------------------------transform_once---------------------------------
1842 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1843 Node *PhaseCCP::transform_once( Node *n ) {
1844 const Type *t = type(n);
1845 // Constant? Use constant Node instead
1846 if( t->singleton() ) {
1847 Node *nn = n; // Default is to return the original constant
1848 if( t == Type::TOP ) {
1849 // cache my top node on the Compile instance
1850 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1851 C->set_cached_top_node(ConNode::make(Type::TOP));
1852 set_type(C->top(), Type::TOP);
1853 }
1854 nn = C->top();
1855 }
1856 if( !n->is_Con() ) {
1857 if( t != Type::TOP ) {
1858 nn = makecon(t); // ConNode::make(t);
1859 NOT_PRODUCT( inc_constants(); )
1860 } else if( n->is_Region() ) { // Unreachable region
1861 // Note: nn == C->top()
1862 n->set_req(0, NULL); // Cut selfreference
1863 // Eagerly remove dead phis to avoid phis copies creation.
1864 for (DUIterator i = n->outs(); n->has_out(i); i++) {
1865 Node* m = n->out(i);
1866 if( m->is_Phi() ) {
1867 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1868 replace_node(m, nn);
1869 --i; // deleted this phi; rescan starting with next position
1870 }
1871 }
1872 }
1873 replace_node(n,nn); // Update DefUse edges for new constant
1874 }
1875 return nn;
1876 }
1877
1878 // If x is a TypeNode, capture any more-precise type permanently into Node
1879 if (t != n->bottom_type()) {
1880 hash_delete(n); // changing bottom type may force a rehash
1881 n->raise_bottom_type(t);
1882 _worklist.push(n); // n re-enters the hash table via the worklist
1883 }
1884
1885 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1886 switch( n->Opcode() ) {
1887 case Op_FastLock: // Revisit FastLocks for lock coarsening
1888 case Op_If:
1889 case Op_CountedLoopEnd:
1890 case Op_Region:
1891 case Op_Loop:
1892 case Op_CountedLoop:
1893 case Op_Conv2B:
1894 case Op_Opaque1:
1895 case Op_Opaque2:
1896 _worklist.push(n);
1897 break;
1898 default:
1899 break;
1900 }
1901
1902 return n;
1903 }
1904
1905 //---------------------------------saturate------------------------------------
1906 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
1907 const Type* limit_type) const {
1908 const Type* wide_type = new_type->widen(old_type, limit_type);
1909 if (wide_type != new_type) { // did we widen?
1910 // If so, we may have widened beyond the limit type. Clip it back down.
1911 new_type = wide_type->filter(limit_type);
1912 }
1913 return new_type;
1914 }
1915
1916 //------------------------------print_statistics-------------------------------
1917 #ifndef PRODUCT
1918 void PhaseCCP::print_statistics() {
1919 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
1920 }
1921 #endif
1922
1923
1924 //=============================================================================
1925 #ifndef PRODUCT
1926 uint PhasePeephole::_total_peepholes = 0;
1927 #endif
1928 //------------------------------PhasePeephole----------------------------------
1929 // Conditional Constant Propagation, ala Wegman & Zadeck
1930 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
1931 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
1932 NOT_PRODUCT( clear_peepholes(); )
1933 }
1934
1935 #ifndef PRODUCT
1936 //------------------------------~PhasePeephole---------------------------------
1937 PhasePeephole::~PhasePeephole() {
1938 _total_peepholes += count_peepholes();
1939 }
1940 #endif
1941
1942 //------------------------------transform--------------------------------------
1943 Node *PhasePeephole::transform( Node *n ) {
1944 ShouldNotCallThis();
1945 return NULL;
1946 }
1947
1948 //------------------------------do_transform-----------------------------------
1949 void PhasePeephole::do_transform() {
1950 bool method_name_not_printed = true;
1951
1952 // Examine each basic block
1953 for (uint block_number = 1; block_number < _cfg.number_of_blocks(); ++block_number) {
1954 Block* block = _cfg.get_block(block_number);
1955 bool block_not_printed = true;
1956
1957 // and each instruction within a block
1958 uint end_index = block->number_of_nodes();
1959 // block->end_idx() not valid after PhaseRegAlloc
1960 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
1961 Node *n = block->get_node(instruction_index);
1962 if( n->is_Mach() ) {
1963 MachNode *m = n->as_Mach();
1964 int deleted_count = 0;
1965 // check for peephole opportunities
1966 MachNode *m2 = m->peephole(block, instruction_index, _regalloc, deleted_count);
1967 if( m2 != NULL ) {
1968 #ifndef PRODUCT
1969 if( PrintOptoPeephole ) {
1970 // Print method, first time only
1971 if( C->method() && method_name_not_printed ) {
1972 C->method()->print_short_name(); tty->cr();
1973 method_name_not_printed = false;
1974 }
1975 // Print this block
1976 if( Verbose && block_not_printed) {
1977 tty->print_cr("in block");
1978 block->dump();
1979 block_not_printed = false;
1980 }
1981 // Print instructions being deleted
1982 for( int i = (deleted_count - 1); i >= 0; --i ) {
1983 block->get_node(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
1984 }
1985 tty->print_cr("replaced with");
1986 // Print new instruction
1987 m2->format(_regalloc);
1988 tty->print("\n\n");
1989 }
1990 #endif
1991 // Remove old nodes from basic block and update instruction_index
1992 // (old nodes still exist and may have edges pointing to them
1993 // as register allocation info is stored in the allocator using
1994 // the node index to live range mappings.)
1995 uint safe_instruction_index = (instruction_index - deleted_count);
1996 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
1997 block->remove_node( instruction_index );
1998 }
1999 // install new node after safe_instruction_index
2000 block->insert_node(m2, safe_instruction_index + 1);
2001 end_index = block->number_of_nodes() - 1; // Recompute new block size
2002 NOT_PRODUCT( inc_peepholes(); )
2003 }
2004 }
2005 }
2006 }
2007 }
2008
2009 //------------------------------print_statistics-------------------------------
2010 #ifndef PRODUCT
2011 void PhasePeephole::print_statistics() {
2012 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
2013 }
2014 #endif
2015
2016
2017 //=============================================================================
2018 //------------------------------set_req_X--------------------------------------
2019 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
2020 assert( is_not_dead(n), "can not use dead node");
2021 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
2022 Node *old = in(i);
2023 set_req(i, n);
2024
2025 // old goes dead?
2026 if( old ) {
2027 switch (old->outcnt()) {
2028 case 0:
2029 // Put into the worklist to kill later. We do not kill it now because the
2030 // recursive kill will delete the current node (this) if dead-loop exists
2031 if (!old->is_top())
2032 igvn->_worklist.push( old );
2033 break;
2034 case 1:
2035 if( old->is_Store() || old->has_special_unique_user() )
2036 igvn->add_users_to_worklist( old );
2037 break;
2038 case 2:
2039 if( old->is_Store() )
2040 igvn->add_users_to_worklist( old );
2041 if( old->Opcode() == Op_Region )
2042 igvn->_worklist.push(old);
2043 break;
2044 case 3:
2045 if( old->Opcode() == Op_Region ) {
2046 igvn->_worklist.push(old);
2047 igvn->add_users_to_worklist( old );
2048 }
2049 break;
2050 default:
2051 break;
2052 }
2053 }
2054
2055 }
2056
2057 //-------------------------------replace_by-----------------------------------
2058 // Using def-use info, replace one node for another. Follow the def-use info
2059 // to all users of the OLD node. Then make all uses point to the NEW node.
2060 void Node::replace_by(Node *new_node) {
2061 assert(!is_top(), "top node has no DU info");
2062 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
2063 Node* use = last_out(i);
2064 uint uses_found = 0;
2065 for (uint j = 0; j < use->len(); j++) {
2066 if (use->in(j) == this) {
2067 if (j < use->req())
2068 use->set_req(j, new_node);
2069 else use->set_prec(j, new_node);
2070 uses_found++;
2071 }
2072 }
2073 i -= uses_found; // we deleted 1 or more copies of this edge
2074 }
2075 }
2076
2077 //=============================================================================
2078 //-----------------------------------------------------------------------------
2079 void Type_Array::grow( uint i ) {
2080 if( !_max ) {
2081 _max = 1;
2082 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
2083 _types[0] = NULL;
2084 }
2085 uint old = _max;
2086 while( i >= _max ) _max <<= 1; // Double to fit
2087 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
2088 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
2089 }
2090
2091 //------------------------------dump-------------------------------------------
2092 #ifndef PRODUCT
2093 void Type_Array::dump() const {
2094 uint max = Size();
2095 for( uint i = 0; i < max; i++ ) {
2096 if( _types[i] != NULL ) {
2097 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
2098 }
2099 }
2100 }
2101 #endif