1 /*
2 * Copyright (c) 1997, 2016, 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(this, &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 const Type* type = gvn->type_or_null(n);
495 new_type_array.map(current_idx, type);
496
497 bool in_worklist = false;
498 if (worklist->member(n)) {
499 in_worklist = true;
500 }
501
502 n->set_idx(current_idx); // Update node ID.
503
504 if (in_worklist) {
505 new_worklist->push(n);
506 }
507
508 current_idx++;
509 }
510
511 assert(worklist_size == new_worklist->size(), "the new worklist must have the same size as the original worklist");
512 assert(live_node_count == current_idx, "all live nodes must be processed");
513
514 // Replace the compiler's type information with the updated type information.
515 gvn->replace_types(new_type_array);
516
517 // Update the unique node count of the compilation to the number of currently live nodes.
518 C->set_unique(live_node_count);
519
520 // Set the dead node count to 0 and reset dead node list.
521 C->reset_dead_node_list();
522 }
523
524
525 //=============================================================================
526 //------------------------------PhaseTransform---------------------------------
527 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
528 _arena(Thread::current()->resource_area()),
529 _nodes(_arena),
530 _types(_arena)
531 {
532 init_con_caches();
533 #ifndef PRODUCT
534 clear_progress();
535 clear_transforms();
536 set_allow_progress(true);
537 #endif
538 // Force allocation for currently existing nodes
539 _types.map(C->unique(), NULL);
540 }
541
542 //------------------------------PhaseTransform---------------------------------
543 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
544 _arena(arena),
545 _nodes(arena),
546 _types(arena)
547 {
548 init_con_caches();
549 #ifndef PRODUCT
550 clear_progress();
551 clear_transforms();
552 set_allow_progress(true);
553 #endif
554 // Force allocation for currently existing nodes
555 _types.map(C->unique(), NULL);
556 }
557
558 //------------------------------PhaseTransform---------------------------------
559 // Initialize with previously generated type information
560 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
561 _arena(pt->_arena),
562 _nodes(pt->_nodes),
563 _types(pt->_types)
564 {
565 init_con_caches();
566 #ifndef PRODUCT
567 clear_progress();
568 clear_transforms();
569 set_allow_progress(true);
570 #endif
571 }
572
573 void PhaseTransform::init_con_caches() {
574 memset(_icons,0,sizeof(_icons));
575 memset(_lcons,0,sizeof(_lcons));
576 memset(_zcons,0,sizeof(_zcons));
577 }
578
579
580 //--------------------------------find_int_type--------------------------------
581 const TypeInt* PhaseTransform::find_int_type(Node* n) {
582 if (n == NULL) return NULL;
583 // Call type_or_null(n) to determine node's type since we might be in
584 // parse phase and call n->Value() may return wrong type.
585 // (For example, a phi node at the beginning of loop parsing is not ready.)
586 const Type* t = type_or_null(n);
587 if (t == NULL) return NULL;
588 return t->isa_int();
589 }
590
591
592 //-------------------------------find_long_type--------------------------------
593 const TypeLong* PhaseTransform::find_long_type(Node* n) {
594 if (n == NULL) return NULL;
595 // (See comment above on type_or_null.)
596 const Type* t = type_or_null(n);
597 if (t == NULL) return NULL;
598 return t->isa_long();
599 }
600
601
602 #ifndef PRODUCT
603 void PhaseTransform::dump_old2new_map() const {
604 _nodes.dump();
605 }
606
607 void PhaseTransform::dump_new( uint nidx ) const {
608 for( uint i=0; i<_nodes.Size(); i++ )
609 if( _nodes[i] && _nodes[i]->_idx == nidx ) {
610 _nodes[i]->dump();
611 tty->cr();
612 tty->print_cr("Old index= %d",i);
613 return;
614 }
615 tty->print_cr("Node %d not found in the new indices", nidx);
616 }
617
618 //------------------------------dump_types-------------------------------------
619 void PhaseTransform::dump_types( ) const {
620 _types.dump();
621 }
622
623 //------------------------------dump_nodes_and_types---------------------------
624 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
625 VectorSet visited(Thread::current()->resource_area());
626 dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
627 }
628
629 //------------------------------dump_nodes_and_types_recur---------------------
630 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
631 if( !n ) return;
632 if( depth == 0 ) return;
633 if( visited.test_set(n->_idx) ) return;
634 for( uint i=0; i<n->len(); i++ ) {
635 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
636 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
637 }
638 n->dump();
639 if (type_or_null(n) != NULL) {
640 tty->print(" "); type(n)->dump(); tty->cr();
641 }
642 }
643
644 #endif
645
646
647 //=============================================================================
648 //------------------------------PhaseValues------------------------------------
649 // Set minimum table size to "255"
650 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
651 NOT_PRODUCT( clear_new_values(); )
652 }
653
654 //------------------------------PhaseValues------------------------------------
655 // Set minimum table size to "255"
656 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
657 _table(&ptv->_table) {
658 NOT_PRODUCT( clear_new_values(); )
659 }
660
661 //------------------------------PhaseValues------------------------------------
662 // Used by +VerifyOpto. Clear out hash table but copy _types array.
663 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
664 _table(ptv->arena(),ptv->_table.size()) {
665 NOT_PRODUCT( clear_new_values(); )
666 }
667
668 //------------------------------~PhaseValues-----------------------------------
669 #ifndef PRODUCT
670 PhaseValues::~PhaseValues() {
671 _table.dump();
672
673 // Statistics for value progress and efficiency
674 if( PrintCompilation && Verbose && WizardMode ) {
675 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
676 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values());
677 if( made_transforms() != 0 ) {
678 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() );
679 } else {
680 tty->cr();
681 }
682 }
683 }
684 #endif
685
686 //------------------------------makecon----------------------------------------
687 ConNode* PhaseTransform::makecon(const Type *t) {
688 assert(t->singleton(), "must be a constant");
689 assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
690 switch (t->base()) { // fast paths
691 case Type::Half:
692 case Type::Top: return (ConNode*) C->top();
693 case Type::Int: return intcon( t->is_int()->get_con() );
694 case Type::Long: return longcon( t->is_long()->get_con() );
695 }
696 if (t->is_zero_type())
697 return zerocon(t->basic_type());
698 return uncached_makecon(t);
699 }
700
701 //--------------------------uncached_makecon-----------------------------------
702 // Make an idealized constant - one of ConINode, ConPNode, etc.
703 ConNode* PhaseValues::uncached_makecon(const Type *t) {
704 assert(t->singleton(), "must be a constant");
705 ConNode* x = ConNode::make(t);
706 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
707 if (k == NULL) {
708 set_type(x, t); // Missed, provide type mapping
709 GrowableArray<Node_Notes*>* nna = C->node_note_array();
710 if (nna != NULL) {
711 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
712 loc->clear(); // do not put debug info on constants
713 }
714 } else {
715 x->destruct(); // Hit, destroy duplicate constant
716 x = k; // use existing constant
717 }
718 return x;
719 }
720
721 //------------------------------intcon-----------------------------------------
722 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
723 ConINode* PhaseTransform::intcon(int i) {
724 // Small integer? Check cache! Check that cached node is not dead
725 if (i >= _icon_min && i <= _icon_max) {
726 ConINode* icon = _icons[i-_icon_min];
727 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
728 return icon;
729 }
730 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
731 assert(icon->is_Con(), "");
732 if (i >= _icon_min && i <= _icon_max)
733 _icons[i-_icon_min] = icon; // Cache small integers
734 return icon;
735 }
736
737 //------------------------------longcon----------------------------------------
738 // Fast long constant.
739 ConLNode* PhaseTransform::longcon(jlong l) {
740 // Small integer? Check cache! Check that cached node is not dead
741 if (l >= _lcon_min && l <= _lcon_max) {
742 ConLNode* lcon = _lcons[l-_lcon_min];
743 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
744 return lcon;
745 }
746 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
747 assert(lcon->is_Con(), "");
748 if (l >= _lcon_min && l <= _lcon_max)
749 _lcons[l-_lcon_min] = lcon; // Cache small integers
750 return lcon;
751 }
752
753 //------------------------------zerocon-----------------------------------------
754 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
755 ConNode* PhaseTransform::zerocon(BasicType bt) {
756 assert((uint)bt <= _zcon_max, "domain check");
757 ConNode* zcon = _zcons[bt];
758 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
759 return zcon;
760 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
761 _zcons[bt] = zcon;
762 return zcon;
763 }
764
765
766
767 //=============================================================================
768 //------------------------------transform--------------------------------------
769 // Return a node which computes the same function as this node, but in a
770 // faster or cheaper fashion.
771 Node *PhaseGVN::transform( Node *n ) {
772 return transform_no_reclaim(n);
773 }
774
775 //------------------------------transform--------------------------------------
776 // Return a node which computes the same function as this node, but
777 // in a faster or cheaper fashion.
778 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
779 NOT_PRODUCT( set_transforms(); )
780
781 // Apply the Ideal call in a loop until it no longer applies
782 Node *k = n;
783 NOT_PRODUCT( uint loop_count = 0; )
784 while( 1 ) {
785 Node *i = k->Ideal(this, /*can_reshape=*/false);
786 if( !i ) break;
787 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
788 k = i;
789 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
790 }
791 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
792
793
794 // If brand new node, make space in type array.
795 ensure_type_or_null(k);
796
797 // Since I just called 'Value' to compute the set of run-time values
798 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
799 // cache Value. Later requests for the local phase->type of this Node can
800 // use the cached Value instead of suffering with 'bottom_type'.
801 const Type *t = k->Value(this); // Get runtime Value set
802 assert(t != NULL, "value sanity");
803 if (type_or_null(k) != t) {
804 #ifndef PRODUCT
805 // Do not count initial visit to node as a transformation
806 if (type_or_null(k) == NULL) {
807 inc_new_values();
808 set_progress();
809 }
810 #endif
811 set_type(k, t);
812 // If k is a TypeNode, capture any more-precise type permanently into Node
813 k->raise_bottom_type(t);
814 }
815
816 if( t->singleton() && !k->is_Con() ) {
817 NOT_PRODUCT( set_progress(); )
818 return makecon(t); // Turn into a constant
819 }
820
821 // Now check for Identities
822 Node *i = k->Identity(this); // Look for a nearby replacement
823 if( i != k ) { // Found? Return replacement!
824 NOT_PRODUCT( set_progress(); )
825 return i;
826 }
827
828 // Global Value Numbering
829 i = hash_find_insert(k); // Insert if new
830 if( i && (i != k) ) {
831 // Return the pre-existing node
832 NOT_PRODUCT( set_progress(); )
833 return i;
834 }
835
836 // Return Idealized original
837 return k;
838 }
839
840 bool PhaseGVN::is_dominator_helper(Node *d, Node *n, bool linear_only) {
841 if (d->is_top() || n->is_top()) {
842 return false;
843 }
844 assert(d->is_CFG() && n->is_CFG(), "must have CFG nodes");
845 int i = 0;
846 while (d != n) {
847 n = IfNode::up_one_dom(n, linear_only);
848 i++;
849 if (n == NULL || i >= 10) {
850 return false;
851 }
852 }
853 return true;
854 }
855
856 #ifdef ASSERT
857 //------------------------------dead_loop_check--------------------------------
858 // Check for a simple dead loop when a data node references itself directly
859 // or through an other data node excluding cons and phis.
860 void PhaseGVN::dead_loop_check( Node *n ) {
861 // Phi may reference itself in a loop
862 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
863 // Do 2 levels check and only data inputs.
864 bool no_dead_loop = true;
865 uint cnt = n->req();
866 for (uint i = 1; i < cnt && no_dead_loop; i++) {
867 Node *in = n->in(i);
868 if (in == n) {
869 no_dead_loop = false;
870 } else if (in != NULL && !in->is_dead_loop_safe()) {
871 uint icnt = in->req();
872 for (uint j = 1; j < icnt && no_dead_loop; j++) {
873 if (in->in(j) == n || in->in(j) == in)
874 no_dead_loop = false;
875 }
876 }
877 }
878 if (!no_dead_loop) n->dump(3);
879 assert(no_dead_loop, "dead loop detected");
880 }
881 }
882 #endif
883
884 //=============================================================================
885 //------------------------------PhaseIterGVN-----------------------------------
886 // Initialize hash table to fresh and clean for +VerifyOpto
887 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ),
888 _stack(C->live_nodes() >> 1),
889 _delay_transform(false) {
890 }
891
892 //------------------------------PhaseIterGVN-----------------------------------
893 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
894 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
895 _worklist( igvn->_worklist ),
896 _stack( igvn->_stack ),
897 _delay_transform(igvn->_delay_transform)
898 {
899 }
900
901 //------------------------------PhaseIterGVN-----------------------------------
902 // Initialize with previous PhaseGVN info from Parser
903 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
904 _worklist(*C->for_igvn()),
905 // TODO: Before incremental inlining it was allocated only once and it was fine. Now that
906 // the constructor is used in incremental inlining, this consumes too much memory:
907 // _stack(C->live_nodes() >> 1),
908 // So, as a band-aid, we replace this by:
909 _stack(C->comp_arena(), 32),
910 _delay_transform(false)
911 {
912 uint max;
913
914 // Dead nodes in the hash table inherited from GVN were not treated as
915 // roots during def-use info creation; hence they represent an invisible
916 // use. Clear them out.
917 max = _table.size();
918 for( uint i = 0; i < max; ++i ) {
919 Node *n = _table.at(i);
920 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
921 if( n->is_top() ) continue;
922 assert( false, "Parse::remove_useless_nodes missed this node");
923 hash_delete(n);
924 }
925 }
926
927 // Any Phis or Regions on the worklist probably had uses that could not
928 // make more progress because the uses were made while the Phis and Regions
929 // were in half-built states. Put all uses of Phis and Regions on worklist.
930 max = _worklist.size();
931 for( uint j = 0; j < max; j++ ) {
932 Node *n = _worklist.at(j);
933 uint uop = n->Opcode();
934 if( uop == Op_Phi || uop == Op_Region ||
935 n->is_Type() ||
936 n->is_Mem() )
937 add_users_to_worklist(n);
938 }
939 }
940
941 /**
942 * Initialize worklist for each node.
943 */
944 void PhaseIterGVN::init_worklist(Node* first) {
945 Unique_Node_List to_process;
946 to_process.push(first);
947
948 while (to_process.size() > 0) {
949 Node* n = to_process.pop();
950 if (!_worklist.member(n)) {
951 _worklist.push(n);
952
953 uint cnt = n->req();
954 for(uint i = 0; i < cnt; i++) {
955 Node* m = n->in(i);
956 if (m != NULL) {
957 to_process.push(m);
958 }
959 }
960 }
961 }
962 }
963
964 #ifndef PRODUCT
965 void PhaseIterGVN::verify_step(Node* n) {
966 if (VerifyIterativeGVN) {
967 _verify_window[_verify_counter % _verify_window_size] = n;
968 ++_verify_counter;
969 ResourceMark rm;
970 ResourceArea* area = Thread::current()->resource_area();
971 VectorSet old_space(area), new_space(area);
972 if (C->unique() < 1000 ||
973 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
974 ++_verify_full_passes;
975 Node::verify_recur(C->root(), -1, old_space, new_space);
976 }
977 const int verify_depth = 4;
978 for ( int i = 0; i < _verify_window_size; i++ ) {
979 Node* n = _verify_window[i];
980 if ( n == NULL ) continue;
981 if( n->in(0) == NodeSentinel ) { // xform_idom
982 _verify_window[i] = n->in(1);
983 --i; continue;
984 }
985 // Typical fanout is 1-2, so this call visits about 6 nodes.
986 Node::verify_recur(n, verify_depth, old_space, new_space);
987 }
988 }
989 }
990
991 void PhaseIterGVN::trace_PhaseIterGVN(Node* n, Node* nn, const Type* oldtype) {
992 if (TraceIterativeGVN) {
993 uint wlsize = _worklist.size();
994 const Type* newtype = type_or_null(n);
995 if (nn != n) {
996 // print old node
997 tty->print("< ");
998 if (oldtype != newtype && oldtype != NULL) {
999 oldtype->dump();
1000 }
1001 do { tty->print("\t"); } while (tty->position() < 16);
1002 tty->print("<");
1003 n->dump();
1004 }
1005 if (oldtype != newtype || nn != n) {
1006 // print new node and/or new type
1007 if (oldtype == NULL) {
1008 tty->print("* ");
1009 } else if (nn != n) {
1010 tty->print("> ");
1011 } else {
1012 tty->print("= ");
1013 }
1014 if (newtype == NULL) {
1015 tty->print("null");
1016 } else {
1017 newtype->dump();
1018 }
1019 do { tty->print("\t"); } while (tty->position() < 16);
1020 nn->dump();
1021 }
1022 if (Verbose && wlsize < _worklist.size()) {
1023 tty->print(" Push {");
1024 while (wlsize != _worklist.size()) {
1025 Node* pushed = _worklist.at(wlsize++);
1026 tty->print(" %d", pushed->_idx);
1027 }
1028 tty->print_cr(" }");
1029 }
1030 if (nn != n) {
1031 // ignore n, it might be subsumed
1032 verify_step((Node*) NULL);
1033 }
1034 }
1035 }
1036
1037 void PhaseIterGVN::init_verifyPhaseIterGVN() {
1038 _verify_counter = 0;
1039 _verify_full_passes = 0;
1040 for (int i = 0; i < _verify_window_size; i++) {
1041 _verify_window[i] = NULL;
1042 }
1043 #ifdef ASSERT
1044 // Verify that all modified nodes are on _worklist
1045 Unique_Node_List* modified_list = C->modified_nodes();
1046 while (modified_list != NULL && modified_list->size()) {
1047 Node* n = modified_list->pop();
1048 if (n->outcnt() != 0 && !n->is_Con() && !_worklist.member(n)) {
1049 n->dump();
1050 assert(false, "modified node is not on IGVN._worklist");
1051 }
1052 }
1053 #endif
1054 }
1055
1056 void PhaseIterGVN::verify_PhaseIterGVN() {
1057 #ifdef ASSERT
1058 // Verify nodes with changed inputs.
1059 Unique_Node_List* modified_list = C->modified_nodes();
1060 while (modified_list != NULL && modified_list->size()) {
1061 Node* n = modified_list->pop();
1062 if (n->outcnt() != 0 && !n->is_Con()) { // skip dead and Con nodes
1063 n->dump();
1064 assert(false, "modified node was not processed by IGVN.transform_old()");
1065 }
1066 }
1067 #endif
1068
1069 C->verify_graph_edges();
1070 if( VerifyOpto && allow_progress() ) {
1071 // Must turn off allow_progress to enable assert and break recursion
1072 C->root()->verify();
1073 { // Check if any progress was missed using IterGVN
1074 // Def-Use info enables transformations not attempted in wash-pass
1075 // e.g. Region/Phi cleanup, ...
1076 // Null-check elision -- may not have reached fixpoint
1077 // do not propagate to dominated nodes
1078 ResourceMark rm;
1079 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
1080 // Fill worklist completely
1081 igvn2.init_worklist(C->root());
1082
1083 igvn2.set_allow_progress(false);
1084 igvn2.optimize();
1085 igvn2.set_allow_progress(true);
1086 }
1087 }
1088 if (VerifyIterativeGVN && PrintOpto) {
1089 if (_verify_counter == _verify_full_passes) {
1090 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
1091 (int) _verify_full_passes);
1092 } else {
1093 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
1094 (int) _verify_counter, (int) _verify_full_passes);
1095 }
1096 }
1097
1098 #ifdef ASSERT
1099 while (modified_list->size()) {
1100 Node* n = modified_list->pop();
1101 n->dump();
1102 assert(false, "VerifyIterativeGVN: new modified node was added");
1103 }
1104 #endif
1105 }
1106 #endif /* PRODUCT */
1107
1108 #ifdef ASSERT
1109 /**
1110 * Dumps information that can help to debug the problem. A debug
1111 * build fails with an assert.
1112 */
1113 void PhaseIterGVN::dump_infinite_loop_info(Node* n) {
1114 n->dump(4);
1115 _worklist.dump();
1116 assert(false, "infinite loop in PhaseIterGVN::optimize");
1117 }
1118
1119 /**
1120 * Prints out information about IGVN if the 'verbose' option is used.
1121 */
1122 void PhaseIterGVN::trace_PhaseIterGVN_verbose(Node* n, int num_processed) {
1123 if (TraceIterativeGVN && Verbose) {
1124 tty->print(" Pop ");
1125 n->dump();
1126 if ((num_processed % 100) == 0) {
1127 _worklist.print_set();
1128 }
1129 }
1130 }
1131 #endif /* ASSERT */
1132
1133 void PhaseIterGVN::optimize() {
1134 DEBUG_ONLY(uint num_processed = 0;)
1135 NOT_PRODUCT(init_verifyPhaseIterGVN();)
1136
1137 uint loop_count = 0;
1138 // Pull from worklist and transform the node. If the node has changed,
1139 // update edge info and put uses on worklist.
1140 while(_worklist.size()) {
1141 if (C->check_node_count(NodeLimitFudgeFactor * 2, "Out of nodes")) {
1142 return;
1143 }
1144 Node* n = _worklist.pop();
1145 if (++loop_count >= K * C->live_nodes()) {
1146 DEBUG_ONLY(dump_infinite_loop_info(n);)
1147 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
1148 return;
1149 }
1150 DEBUG_ONLY(trace_PhaseIterGVN_verbose(n, num_processed++);)
1151 if (n->outcnt() != 0) {
1152 NOT_PRODUCT(const Type* oldtype = type_or_null(n));
1153 // Do the transformation
1154 Node* nn = transform_old(n);
1155 NOT_PRODUCT(trace_PhaseIterGVN(n, nn, oldtype);)
1156 } else if (!n->is_top()) {
1157 remove_dead_node(n);
1158 }
1159 }
1160 NOT_PRODUCT(verify_PhaseIterGVN();)
1161 }
1162
1163
1164 /**
1165 * Register a new node with the optimizer. Update the types array, the def-use
1166 * info. Put on worklist.
1167 */
1168 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
1169 set_type_bottom(n);
1170 _worklist.push(n);
1171 if (orig != NULL) C->copy_node_notes_to(n, orig);
1172 return n;
1173 }
1174
1175 //------------------------------transform--------------------------------------
1176 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
1177 Node *PhaseIterGVN::transform( Node *n ) {
1178 if (_delay_transform) {
1179 // Register the node but don't optimize for now
1180 register_new_node_with_optimizer(n);
1181 return n;
1182 }
1183
1184 // If brand new node, make space in type array, and give it a type.
1185 ensure_type_or_null(n);
1186 if (type_or_null(n) == NULL) {
1187 set_type_bottom(n);
1188 }
1189
1190 return transform_old(n);
1191 }
1192
1193 Node *PhaseIterGVN::transform_old(Node* n) {
1194 DEBUG_ONLY(uint loop_count = 0;);
1195 NOT_PRODUCT(set_transforms());
1196
1197 // Remove 'n' from hash table in case it gets modified
1198 _table.hash_delete(n);
1199 if (VerifyIterativeGVN) {
1200 assert(!_table.find_index(n->_idx), "found duplicate entry in table");
1201 }
1202
1203 // Apply the Ideal call in a loop until it no longer applies
1204 Node* k = n;
1205 DEBUG_ONLY(dead_loop_check(k);)
1206 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1207 C->remove_modified_node(k);
1208 Node* i = k->Ideal(this, /*can_reshape=*/true);
1209 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1210 #ifndef PRODUCT
1211 verify_step(k);
1212 if (i && VerifyOpto ) {
1213 if (!allow_progress()) {
1214 if (i->is_Add() && (i->outcnt() == 1)) {
1215 // Switched input to left side because this is the only use
1216 } else if (i->is_If() && (i->in(0) == NULL)) {
1217 // This IF is dead because it is dominated by an equivalent IF When
1218 // dominating if changed, info is not propagated sparsely to 'this'
1219 // Propagating this info further will spuriously identify other
1220 // progress.
1221 return i;
1222 } else
1223 set_progress();
1224 } else {
1225 set_progress();
1226 }
1227 }
1228 #endif
1229
1230 while (i != NULL) {
1231 #ifdef ASSERT
1232 if (loop_count >= K) {
1233 dump_infinite_loop_info(i);
1234 }
1235 loop_count++;
1236 #endif
1237 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1238 // Made a change; put users of original Node on worklist
1239 add_users_to_worklist(k);
1240 // Replacing root of transform tree?
1241 if (k != i) {
1242 // Make users of old Node now use new.
1243 subsume_node(k, i);
1244 k = i;
1245 }
1246 DEBUG_ONLY(dead_loop_check(k);)
1247 // Try idealizing again
1248 DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1249 C->remove_modified_node(k);
1250 i = k->Ideal(this, /*can_reshape=*/true);
1251 assert(i != k || is_new || (i->outcnt() > 0), "don't return dead nodes");
1252 #ifndef PRODUCT
1253 verify_step(k);
1254 if (i && VerifyOpto) {
1255 set_progress();
1256 }
1257 #endif
1258 }
1259
1260 // If brand new node, make space in type array.
1261 ensure_type_or_null(k);
1262
1263 // See what kind of values 'k' takes on at runtime
1264 const Type* t = k->Value(this);
1265 assert(t != NULL, "value sanity");
1266
1267 // Since I just called 'Value' to compute the set of run-time values
1268 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1269 // cache Value. Later requests for the local phase->type of this Node can
1270 // use the cached Value instead of suffering with 'bottom_type'.
1271 if (type_or_null(k) != t) {
1272 #ifndef PRODUCT
1273 inc_new_values();
1274 set_progress();
1275 #endif
1276 set_type(k, t);
1277 // If k is a TypeNode, capture any more-precise type permanently into Node
1278 k->raise_bottom_type(t);
1279 // Move users of node to worklist
1280 add_users_to_worklist(k);
1281 }
1282 // If 'k' computes a constant, replace it with a constant
1283 if (t->singleton() && !k->is_Con()) {
1284 NOT_PRODUCT(set_progress();)
1285 Node* con = makecon(t); // Make a constant
1286 add_users_to_worklist(k);
1287 subsume_node(k, con); // Everybody using k now uses con
1288 return con;
1289 }
1290
1291 // Now check for Identities
1292 i = k->Identity(this); // Look for a nearby replacement
1293 if (i != k) { // Found? Return replacement!
1294 NOT_PRODUCT(set_progress();)
1295 add_users_to_worklist(k);
1296 subsume_node(k, i); // Everybody using k now uses i
1297 return i;
1298 }
1299
1300 // Global Value Numbering
1301 i = hash_find_insert(k); // Check for pre-existing node
1302 if (i && (i != k)) {
1303 // Return the pre-existing node if it isn't dead
1304 NOT_PRODUCT(set_progress();)
1305 add_users_to_worklist(k);
1306 subsume_node(k, i); // Everybody using k now uses i
1307 return i;
1308 }
1309
1310 // Return Idealized original
1311 return k;
1312 }
1313
1314 //---------------------------------saturate------------------------------------
1315 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1316 const Type* limit_type) const {
1317 return new_type->narrow(old_type);
1318 }
1319
1320 //------------------------------remove_globally_dead_node----------------------
1321 // Kill a globally dead Node. All uses are also globally dead and are
1322 // aggressively trimmed.
1323 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1324 enum DeleteProgress {
1325 PROCESS_INPUTS,
1326 PROCESS_OUTPUTS
1327 };
1328 assert(_stack.is_empty(), "not empty");
1329 _stack.push(dead, PROCESS_INPUTS);
1330
1331 while (_stack.is_nonempty()) {
1332 dead = _stack.node();
1333 uint progress_state = _stack.index();
1334 assert(dead != C->root(), "killing root, eh?");
1335 assert(!dead->is_top(), "add check for top when pushing");
1336 NOT_PRODUCT( set_progress(); )
1337 if (progress_state == PROCESS_INPUTS) {
1338 // After following inputs, continue to outputs
1339 _stack.set_index(PROCESS_OUTPUTS);
1340 if (!dead->is_Con()) { // Don't kill cons but uses
1341 bool recurse = false;
1342 // Remove from hash table
1343 _table.hash_delete( dead );
1344 // Smash all inputs to 'dead', isolating him completely
1345 for (uint i = 0; i < dead->req(); i++) {
1346 Node *in = dead->in(i);
1347 if (in != NULL && in != C->top()) { // Points to something?
1348 int nrep = dead->replace_edge(in, NULL); // Kill edges
1349 assert((nrep > 0), "sanity");
1350 if (in->outcnt() == 0) { // Made input go dead?
1351 _stack.push(in, PROCESS_INPUTS); // Recursively remove
1352 recurse = true;
1353 } else if (in->outcnt() == 1 &&
1354 in->has_special_unique_user()) {
1355 _worklist.push(in->unique_out());
1356 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1357 if (in->Opcode() == Op_Region) {
1358 _worklist.push(in);
1359 } else if (in->is_Store()) {
1360 DUIterator_Fast imax, i = in->fast_outs(imax);
1361 _worklist.push(in->fast_out(i));
1362 i++;
1363 if (in->outcnt() == 2) {
1364 _worklist.push(in->fast_out(i));
1365 i++;
1366 }
1367 assert(!(i < imax), "sanity");
1368 }
1369 }
1370 if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory &&
1371 in->is_Proj() && in->in(0) != NULL && in->in(0)->is_Initialize()) {
1372 // A Load that directly follows an InitializeNode is
1373 // going away. The Stores that follow are candidates
1374 // again to be captured by the InitializeNode.
1375 for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) {
1376 Node *n = in->fast_out(j);
1377 if (n->is_Store()) {
1378 _worklist.push(n);
1379 }
1380 }
1381 }
1382 } // if (in != NULL && in != C->top())
1383 } // for (uint i = 0; i < dead->req(); i++)
1384 if (recurse) {
1385 continue;
1386 }
1387 } // if (!dead->is_Con())
1388 } // if (progress_state == PROCESS_INPUTS)
1389
1390 // Aggressively kill globally dead uses
1391 // (Rather than pushing all the outs at once, we push one at a time,
1392 // plus the parent to resume later, because of the indefinite number
1393 // of edge deletions per loop trip.)
1394 if (dead->outcnt() > 0) {
1395 // Recursively remove output edges
1396 _stack.push(dead->raw_out(0), PROCESS_INPUTS);
1397 } else {
1398 // Finished disconnecting all input and output edges.
1399 _stack.pop();
1400 // Remove dead node from iterative worklist
1401 _worklist.remove(dead);
1402 C->remove_modified_node(dead);
1403 // Constant node that has no out-edges and has only one in-edge from
1404 // root is usually dead. However, sometimes reshaping walk makes
1405 // it reachable by adding use edges. So, we will NOT count Con nodes
1406 // as dead to be conservative about the dead node count at any
1407 // given time.
1408 if (!dead->is_Con()) {
1409 C->record_dead_node(dead->_idx);
1410 }
1411 if (dead->is_macro()) {
1412 C->remove_macro_node(dead);
1413 }
1414 if (dead->is_expensive()) {
1415 C->remove_expensive_node(dead);
1416 }
1417 CastIINode* cast = dead->isa_CastII();
1418 if (cast != NULL && cast->has_range_check()) {
1419 C->remove_range_check_cast(cast);
1420 }
1421 }
1422 } // while (_stack.is_nonempty())
1423 }
1424
1425 //------------------------------subsume_node-----------------------------------
1426 // Remove users from node 'old' and add them to node 'nn'.
1427 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1428 assert( old != hash_find(old), "should already been removed" );
1429 assert( old != C->top(), "cannot subsume top node");
1430 // Copy debug or profile information to the new version:
1431 C->copy_node_notes_to(nn, old);
1432 // Move users of node 'old' to node 'nn'
1433 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1434 Node* use = old->last_out(i); // for each use...
1435 // use might need re-hashing (but it won't if it's a new node)
1436 rehash_node_delayed(use);
1437 // Update use-def info as well
1438 // We remove all occurrences of old within use->in,
1439 // so as to avoid rehashing any node more than once.
1440 // The hash table probe swamps any outer loop overhead.
1441 uint num_edges = 0;
1442 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1443 if (use->in(j) == old) {
1444 use->set_req(j, nn);
1445 ++num_edges;
1446 }
1447 }
1448 i -= num_edges; // we deleted 1 or more copies of this edge
1449 }
1450
1451 // Smash all inputs to 'old', isolating him completely
1452 Node *temp = new Node(1);
1453 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1454 remove_dead_node( old );
1455 temp->del_req(0); // Yank bogus edge
1456 #ifndef PRODUCT
1457 if( VerifyIterativeGVN ) {
1458 for ( int i = 0; i < _verify_window_size; i++ ) {
1459 if ( _verify_window[i] == old )
1460 _verify_window[i] = nn;
1461 }
1462 }
1463 #endif
1464 _worklist.remove(temp); // this can be necessary
1465 temp->destruct(); // reuse the _idx of this little guy
1466 }
1467
1468 //------------------------------add_users_to_worklist--------------------------
1469 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1470 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1471 _worklist.push(n->fast_out(i)); // Push on worklist
1472 }
1473 }
1474
1475 // Return counted loop Phi if as a counted loop exit condition, cmp
1476 // compares the the induction variable with n
1477 static PhiNode* countedloop_phi_from_cmp(CmpINode* cmp, Node* n) {
1478 for (DUIterator_Fast imax, i = cmp->fast_outs(imax); i < imax; i++) {
1479 Node* bol = cmp->fast_out(i);
1480 for (DUIterator_Fast i2max, i2 = bol->fast_outs(i2max); i2 < i2max; i2++) {
1481 Node* iff = bol->fast_out(i2);
1482 if (iff->is_CountedLoopEnd()) {
1483 CountedLoopEndNode* cle = iff->as_CountedLoopEnd();
1484 if (cle->limit() == n) {
1485 PhiNode* phi = cle->phi();
1486 if (phi != NULL) {
1487 return phi;
1488 }
1489 }
1490 }
1491 }
1492 }
1493 return NULL;
1494 }
1495
1496 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1497 add_users_to_worklist0(n);
1498
1499 // Move users of node to worklist
1500 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1501 Node* use = n->fast_out(i); // Get use
1502
1503 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1504 use->is_Store() ) // Enable store/load same address
1505 add_users_to_worklist0(use);
1506
1507 // If we changed the receiver type to a call, we need to revisit
1508 // the Catch following the call. It's looking for a non-NULL
1509 // receiver to know when to enable the regular fall-through path
1510 // in addition to the NullPtrException path.
1511 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1512 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control);
1513 if (p != NULL) {
1514 add_users_to_worklist0(p);
1515 }
1516 }
1517
1518 uint use_op = use->Opcode();
1519 if(use->is_Cmp()) { // Enable CMP/BOOL optimization
1520 add_users_to_worklist(use); // Put Bool on worklist
1521 if (use->outcnt() > 0) {
1522 Node* bol = use->raw_out(0);
1523 if (bol->outcnt() > 0) {
1524 Node* iff = bol->raw_out(0);
1525 if (iff->outcnt() == 2) {
1526 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1527 // phi merging either 0 or 1 onto the worklist
1528 Node* ifproj0 = iff->raw_out(0);
1529 Node* ifproj1 = iff->raw_out(1);
1530 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1531 Node* region0 = ifproj0->raw_out(0);
1532 Node* region1 = ifproj1->raw_out(0);
1533 if( region0 == region1 )
1534 add_users_to_worklist0(region0);
1535 }
1536 }
1537 }
1538 }
1539 if (use_op == Op_CmpI) {
1540 Node* phi = countedloop_phi_from_cmp((CmpINode*)use, n);
1541 if (phi != NULL) {
1542 // If an opaque node feeds into the limit condition of a
1543 // CountedLoop, we need to process the Phi node for the
1544 // induction variable when the opaque node is removed:
1545 // the range of values taken by the Phi is now known and
1546 // so its type is also known.
1547 _worklist.push(phi);
1548 }
1549 Node* in1 = use->in(1);
1550 for (uint i = 0; i < in1->outcnt(); i++) {
1551 if (in1->raw_out(i)->Opcode() == Op_CastII) {
1552 Node* castii = in1->raw_out(i);
1553 if (castii->in(0) != NULL && castii->in(0)->in(0) != NULL && castii->in(0)->in(0)->is_If()) {
1554 Node* ifnode = castii->in(0)->in(0);
1555 if (ifnode->in(1) != NULL && ifnode->in(1)->is_Bool() && ifnode->in(1)->in(1) == use) {
1556 // Reprocess a CastII node that may depend on an
1557 // opaque node value when the opaque node is
1558 // removed. In case it carries a dependency we can do
1559 // a better job of computing its type.
1560 _worklist.push(castii);
1561 }
1562 }
1563 }
1564 }
1565 }
1566 }
1567
1568 // If changed Cast input, check Phi users for simple cycles
1569 if (use->is_ConstraintCast()) {
1570 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1571 Node* u = use->fast_out(i2);
1572 if (u->is_Phi())
1573 _worklist.push(u);
1574 }
1575 }
1576 // If changed LShift inputs, check RShift users for useless sign-ext
1577 if( use_op == Op_LShiftI ) {
1578 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1579 Node* u = use->fast_out(i2);
1580 if (u->Opcode() == Op_RShiftI)
1581 _worklist.push(u);
1582 }
1583 }
1584 // If changed AddI/SubI inputs, check CmpU for range check optimization.
1585 if (use_op == Op_AddI || use_op == Op_SubI) {
1586 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1587 Node* u = use->fast_out(i2);
1588 if (u->is_Cmp() && (u->Opcode() == Op_CmpU)) {
1589 _worklist.push(u);
1590 }
1591 }
1592 }
1593 // If changed AddP inputs, check Stores for loop invariant
1594 if( use_op == Op_AddP ) {
1595 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1596 Node* u = use->fast_out(i2);
1597 if (u->is_Mem())
1598 _worklist.push(u);
1599 }
1600 }
1601 // If changed initialization activity, check dependent Stores
1602 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1603 InitializeNode* init = use->as_Allocate()->initialization();
1604 if (init != NULL) {
1605 Node* imem = init->proj_out(TypeFunc::Memory);
1606 if (imem != NULL) add_users_to_worklist0(imem);
1607 }
1608 }
1609 if (use_op == Op_Initialize) {
1610 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory);
1611 if (imem != NULL) add_users_to_worklist0(imem);
1612 }
1613 }
1614 }
1615
1616 /**
1617 * Remove the speculative part of all types that we know of
1618 */
1619 void PhaseIterGVN::remove_speculative_types() {
1620 assert(UseTypeSpeculation, "speculation is off");
1621 for (uint i = 0; i < _types.Size(); i++) {
1622 const Type* t = _types.fast_lookup(i);
1623 if (t != NULL) {
1624 _types.map(i, t->remove_speculative());
1625 }
1626 }
1627 _table.check_no_speculative_types();
1628 }
1629
1630 //=============================================================================
1631 #ifndef PRODUCT
1632 uint PhaseCCP::_total_invokes = 0;
1633 uint PhaseCCP::_total_constants = 0;
1634 #endif
1635 //------------------------------PhaseCCP---------------------------------------
1636 // Conditional Constant Propagation, ala Wegman & Zadeck
1637 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1638 NOT_PRODUCT( clear_constants(); )
1639 assert( _worklist.size() == 0, "" );
1640 // Clear out _nodes from IterGVN. Must be clear to transform call.
1641 _nodes.clear(); // Clear out from IterGVN
1642 analyze();
1643 }
1644
1645 #ifndef PRODUCT
1646 //------------------------------~PhaseCCP--------------------------------------
1647 PhaseCCP::~PhaseCCP() {
1648 inc_invokes();
1649 _total_constants += count_constants();
1650 }
1651 #endif
1652
1653
1654 #ifdef ASSERT
1655 static bool ccp_type_widens(const Type* t, const Type* t0) {
1656 assert(t->meet(t0) == t, "Not monotonic");
1657 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1658 case Type::Int:
1659 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1660 break;
1661 case Type::Long:
1662 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1663 break;
1664 }
1665 return true;
1666 }
1667 #endif //ASSERT
1668
1669 //------------------------------analyze----------------------------------------
1670 void PhaseCCP::analyze() {
1671 // Initialize all types to TOP, optimistic analysis
1672 for (int i = C->unique() - 1; i >= 0; i--) {
1673 _types.map(i,Type::TOP);
1674 }
1675
1676 // Push root onto worklist
1677 Unique_Node_List worklist;
1678 worklist.push(C->root());
1679
1680 // Pull from worklist; compute new value; push changes out.
1681 // This loop is the meat of CCP.
1682 while( worklist.size() ) {
1683 Node *n = worklist.pop();
1684 const Type *t = n->Value(this);
1685 if (t != type(n)) {
1686 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1687 #ifndef PRODUCT
1688 if( TracePhaseCCP ) {
1689 t->dump();
1690 do { tty->print("\t"); } while (tty->position() < 16);
1691 n->dump();
1692 }
1693 #endif
1694 set_type(n, t);
1695 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1696 Node* m = n->fast_out(i); // Get user
1697 if (m->is_Region()) { // New path to Region? Must recheck Phis too
1698 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1699 Node* p = m->fast_out(i2); // Propagate changes to uses
1700 if (p->bottom_type() != type(p)) { // If not already bottomed out
1701 worklist.push(p); // Propagate change to user
1702 }
1703 }
1704 }
1705 // If we changed the receiver type to a call, we need to revisit
1706 // the Catch following the call. It's looking for a non-NULL
1707 // receiver to know when to enable the regular fall-through path
1708 // in addition to the NullPtrException path
1709 if (m->is_Call()) {
1710 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1711 Node* p = m->fast_out(i2); // Propagate changes to uses
1712 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1) {
1713 worklist.push(p->unique_out());
1714 }
1715 }
1716 }
1717 if (m->bottom_type() != type(m)) { // If not already bottomed out
1718 worklist.push(m); // Propagate change to user
1719 }
1720
1721 // CmpU nodes can get their type information from two nodes up in the
1722 // graph (instead of from the nodes immediately above). Make sure they
1723 // are added to the worklist if nodes they depend on are updated, since
1724 // they could be missed and get wrong types otherwise.
1725 uint m_op = m->Opcode();
1726 if (m_op == Op_AddI || m_op == Op_SubI) {
1727 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1728 Node* p = m->fast_out(i2); // Propagate changes to uses
1729 if (p->Opcode() == Op_CmpU) {
1730 // Got a CmpU which might need the new type information from node n.
1731 if(p->bottom_type() != type(p)) { // If not already bottomed out
1732 worklist.push(p); // Propagate change to user
1733 }
1734 }
1735 }
1736 }
1737 // If n is used in a counted loop exit condition then the type
1738 // of the counted loop's Phi depends on the type of n. See
1739 // PhiNode::Value().
1740 if (m_op == Op_CmpI) {
1741 PhiNode* phi = countedloop_phi_from_cmp((CmpINode*)m, n);
1742 if (phi != NULL) {
1743 worklist.push(phi);
1744 }
1745 }
1746 }
1747 }
1748 }
1749 }
1750
1751 //------------------------------do_transform-----------------------------------
1752 // Top level driver for the recursive transformer
1753 void PhaseCCP::do_transform() {
1754 // Correct leaves of new-space Nodes; they point to old-space.
1755 C->set_root( transform(C->root())->as_Root() );
1756 assert( C->top(), "missing TOP node" );
1757 assert( C->root(), "missing root" );
1758 }
1759
1760 //------------------------------transform--------------------------------------
1761 // Given a Node in old-space, clone him into new-space.
1762 // Convert any of his old-space children into new-space children.
1763 Node *PhaseCCP::transform( Node *n ) {
1764 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1765 if( new_node != NULL )
1766 return new_node; // Been there, done that, return old answer
1767 new_node = transform_once(n); // Check for constant
1768 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1769
1770 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1771 GrowableArray <Node *> trstack(C->live_nodes() >> 1);
1772
1773 trstack.push(new_node); // Process children of cloned node
1774 while ( trstack.is_nonempty() ) {
1775 Node *clone = trstack.pop();
1776 uint cnt = clone->req();
1777 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1778 Node *input = clone->in(i);
1779 if( input != NULL ) { // Ignore NULLs
1780 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1781 if( new_input == NULL ) {
1782 new_input = transform_once(input); // Check for constant
1783 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1784 trstack.push(new_input);
1785 }
1786 assert( new_input == clone->in(i), "insanity check");
1787 }
1788 }
1789 }
1790 return new_node;
1791 }
1792
1793
1794 //------------------------------transform_once---------------------------------
1795 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1796 Node *PhaseCCP::transform_once( Node *n ) {
1797 const Type *t = type(n);
1798 // Constant? Use constant Node instead
1799 if( t->singleton() ) {
1800 Node *nn = n; // Default is to return the original constant
1801 if( t == Type::TOP ) {
1802 // cache my top node on the Compile instance
1803 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1804 C->set_cached_top_node(ConNode::make(Type::TOP));
1805 set_type(C->top(), Type::TOP);
1806 }
1807 nn = C->top();
1808 }
1809 if( !n->is_Con() ) {
1810 if( t != Type::TOP ) {
1811 nn = makecon(t); // ConNode::make(t);
1812 NOT_PRODUCT( inc_constants(); )
1813 } else if( n->is_Region() ) { // Unreachable region
1814 // Note: nn == C->top()
1815 n->set_req(0, NULL); // Cut selfreference
1816 // Eagerly remove dead phis to avoid phis copies creation.
1817 for (DUIterator i = n->outs(); n->has_out(i); i++) {
1818 Node* m = n->out(i);
1819 if( m->is_Phi() ) {
1820 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1821 replace_node(m, nn);
1822 --i; // deleted this phi; rescan starting with next position
1823 }
1824 }
1825 }
1826 replace_node(n,nn); // Update DefUse edges for new constant
1827 }
1828 return nn;
1829 }
1830
1831 // If x is a TypeNode, capture any more-precise type permanently into Node
1832 if (t != n->bottom_type()) {
1833 hash_delete(n); // changing bottom type may force a rehash
1834 n->raise_bottom_type(t);
1835 _worklist.push(n); // n re-enters the hash table via the worklist
1836 }
1837
1838 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1839 switch( n->Opcode() ) {
1840 case Op_FastLock: // Revisit FastLocks for lock coarsening
1841 case Op_If:
1842 case Op_CountedLoopEnd:
1843 case Op_Region:
1844 case Op_Loop:
1845 case Op_CountedLoop:
1846 case Op_Conv2B:
1847 case Op_Opaque1:
1848 case Op_Opaque2:
1849 _worklist.push(n);
1850 break;
1851 default:
1852 break;
1853 }
1854
1855 return n;
1856 }
1857
1858 //---------------------------------saturate------------------------------------
1859 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
1860 const Type* limit_type) const {
1861 const Type* wide_type = new_type->widen(old_type, limit_type);
1862 if (wide_type != new_type) { // did we widen?
1863 // If so, we may have widened beyond the limit type. Clip it back down.
1864 new_type = wide_type->filter(limit_type);
1865 }
1866 return new_type;
1867 }
1868
1869 //------------------------------print_statistics-------------------------------
1870 #ifndef PRODUCT
1871 void PhaseCCP::print_statistics() {
1872 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
1873 }
1874 #endif
1875
1876
1877 //=============================================================================
1878 #ifndef PRODUCT
1879 uint PhasePeephole::_total_peepholes = 0;
1880 #endif
1881 //------------------------------PhasePeephole----------------------------------
1882 // Conditional Constant Propagation, ala Wegman & Zadeck
1883 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
1884 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
1885 NOT_PRODUCT( clear_peepholes(); )
1886 }
1887
1888 #ifndef PRODUCT
1889 //------------------------------~PhasePeephole---------------------------------
1890 PhasePeephole::~PhasePeephole() {
1891 _total_peepholes += count_peepholes();
1892 }
1893 #endif
1894
1895 //------------------------------transform--------------------------------------
1896 Node *PhasePeephole::transform( Node *n ) {
1897 ShouldNotCallThis();
1898 return NULL;
1899 }
1900
1901 //------------------------------do_transform-----------------------------------
1902 void PhasePeephole::do_transform() {
1903 bool method_name_not_printed = true;
1904
1905 // Examine each basic block
1906 for (uint block_number = 1; block_number < _cfg.number_of_blocks(); ++block_number) {
1907 Block* block = _cfg.get_block(block_number);
1908 bool block_not_printed = true;
1909
1910 // and each instruction within a block
1911 uint end_index = block->number_of_nodes();
1912 // block->end_idx() not valid after PhaseRegAlloc
1913 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
1914 Node *n = block->get_node(instruction_index);
1915 if( n->is_Mach() ) {
1916 MachNode *m = n->as_Mach();
1917 int deleted_count = 0;
1918 // check for peephole opportunities
1919 MachNode *m2 = m->peephole(block, instruction_index, _regalloc, deleted_count);
1920 if( m2 != NULL ) {
1921 #ifndef PRODUCT
1922 if( PrintOptoPeephole ) {
1923 // Print method, first time only
1924 if( C->method() && method_name_not_printed ) {
1925 C->method()->print_short_name(); tty->cr();
1926 method_name_not_printed = false;
1927 }
1928 // Print this block
1929 if( Verbose && block_not_printed) {
1930 tty->print_cr("in block");
1931 block->dump();
1932 block_not_printed = false;
1933 }
1934 // Print instructions being deleted
1935 for( int i = (deleted_count - 1); i >= 0; --i ) {
1936 block->get_node(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
1937 }
1938 tty->print_cr("replaced with");
1939 // Print new instruction
1940 m2->format(_regalloc);
1941 tty->print("\n\n");
1942 }
1943 #endif
1944 // Remove old nodes from basic block and update instruction_index
1945 // (old nodes still exist and may have edges pointing to them
1946 // as register allocation info is stored in the allocator using
1947 // the node index to live range mappings.)
1948 uint safe_instruction_index = (instruction_index - deleted_count);
1949 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
1950 block->remove_node( instruction_index );
1951 }
1952 // install new node after safe_instruction_index
1953 block->insert_node(m2, safe_instruction_index + 1);
1954 end_index = block->number_of_nodes() - 1; // Recompute new block size
1955 NOT_PRODUCT( inc_peepholes(); )
1956 }
1957 }
1958 }
1959 }
1960 }
1961
1962 //------------------------------print_statistics-------------------------------
1963 #ifndef PRODUCT
1964 void PhasePeephole::print_statistics() {
1965 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
1966 }
1967 #endif
1968
1969
1970 //=============================================================================
1971 //------------------------------set_req_X--------------------------------------
1972 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
1973 assert( is_not_dead(n), "can not use dead node");
1974 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
1975 Node *old = in(i);
1976 set_req(i, n);
1977
1978 // old goes dead?
1979 if( old ) {
1980 switch (old->outcnt()) {
1981 case 0:
1982 // Put into the worklist to kill later. We do not kill it now because the
1983 // recursive kill will delete the current node (this) if dead-loop exists
1984 if (!old->is_top())
1985 igvn->_worklist.push( old );
1986 break;
1987 case 1:
1988 if( old->is_Store() || old->has_special_unique_user() )
1989 igvn->add_users_to_worklist( old );
1990 break;
1991 case 2:
1992 if( old->is_Store() )
1993 igvn->add_users_to_worklist( old );
1994 if( old->Opcode() == Op_Region )
1995 igvn->_worklist.push(old);
1996 break;
1997 case 3:
1998 if( old->Opcode() == Op_Region ) {
1999 igvn->_worklist.push(old);
2000 igvn->add_users_to_worklist( old );
2001 }
2002 break;
2003 default:
2004 break;
2005 }
2006 }
2007
2008 }
2009
2010 //-------------------------------replace_by-----------------------------------
2011 // Using def-use info, replace one node for another. Follow the def-use info
2012 // to all users of the OLD node. Then make all uses point to the NEW node.
2013 void Node::replace_by(Node *new_node) {
2014 assert(!is_top(), "top node has no DU info");
2015 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
2016 Node* use = last_out(i);
2017 uint uses_found = 0;
2018 for (uint j = 0; j < use->len(); j++) {
2019 if (use->in(j) == this) {
2020 if (j < use->req())
2021 use->set_req(j, new_node);
2022 else use->set_prec(j, new_node);
2023 uses_found++;
2024 }
2025 }
2026 i -= uses_found; // we deleted 1 or more copies of this edge
2027 }
2028 }
2029
2030 //=============================================================================
2031 //-----------------------------------------------------------------------------
2032 void Type_Array::grow( uint i ) {
2033 if( !_max ) {
2034 _max = 1;
2035 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
2036 _types[0] = NULL;
2037 }
2038 uint old = _max;
2039 while( i >= _max ) _max <<= 1; // Double to fit
2040 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
2041 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
2042 }
2043
2044 //------------------------------dump-------------------------------------------
2045 #ifndef PRODUCT
2046 void Type_Array::dump() const {
2047 uint max = Size();
2048 for( uint i = 0; i < max; i++ ) {
2049 if( _types[i] != NULL ) {
2050 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
2051 }
2052 }
2053 }
2054 #endif