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 // 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 }
698 if (t->is_zero_type())
699 return zerocon(t->basic_type());
700 return uncached_makecon(t);
701 }
702
703 //--------------------------uncached_makecon-----------------------------------
704 // Make an idealized constant - one of ConINode, ConPNode, etc.
705 ConNode* PhaseValues::uncached_makecon(const Type *t) {
706 assert(t->singleton(), "must be a constant");
707 ConNode* x = ConNode::make(t);
708 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
709 if (k == NULL) {
710 set_type(x, t); // Missed, provide type mapping
711 GrowableArray<Node_Notes*>* nna = C->node_note_array();
712 if (nna != NULL) {
713 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
714 loc->clear(); // do not put debug info on constants
715 }
716 } else {
717 x->destruct(); // Hit, destroy duplicate constant
718 x = k; // use existing constant
719 }
720 return x;
721 }
722
723 //------------------------------intcon-----------------------------------------
724 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
725 ConINode* PhaseTransform::intcon(int i) {
726 // Small integer? Check cache! Check that cached node is not dead
727 if (i >= _icon_min && i <= _icon_max) {
728 ConINode* icon = _icons[i-_icon_min];
729 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
730 return icon;
731 }
732 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
733 assert(icon->is_Con(), "");
734 if (i >= _icon_min && i <= _icon_max)
735 _icons[i-_icon_min] = icon; // Cache small integers
736 return icon;
737 }
738
739 //------------------------------longcon----------------------------------------
740 // Fast long constant.
741 ConLNode* PhaseTransform::longcon(jlong l) {
742 // Small integer? Check cache! Check that cached node is not dead
743 if (l >= _lcon_min && l <= _lcon_max) {
744 ConLNode* lcon = _lcons[l-_lcon_min];
745 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
746 return lcon;
747 }
748 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
749 assert(lcon->is_Con(), "");
750 if (l >= _lcon_min && l <= _lcon_max)
751 _lcons[l-_lcon_min] = lcon; // Cache small integers
752 return lcon;
753 }
754
755 //------------------------------zerocon-----------------------------------------
756 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
757 ConNode* PhaseTransform::zerocon(BasicType bt) {
758 assert((uint)bt <= _zcon_max, "domain check");
759 ConNode* zcon = _zcons[bt];
760 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
761 return zcon;
762 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
763 _zcons[bt] = zcon;
764 return zcon;
765 }
766
767
768
769 //=============================================================================
770 //------------------------------transform--------------------------------------
771 // Return a node which computes the same function as this node, but in a
772 // faster or cheaper fashion.
773 Node *PhaseGVN::transform( Node *n ) {
774 return transform_no_reclaim(n);
775 }
776
777 //------------------------------transform--------------------------------------
778 // Return a node which computes the same function as this node, but
779 // in a faster or cheaper fashion.
780 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
781 NOT_PRODUCT( set_transforms(); )
782
783 // Apply the Ideal call in a loop until it no longer applies
784 Node *k = n;
785 NOT_PRODUCT( uint loop_count = 0; )
786 while( 1 ) {
787 Node *i = k->Ideal(this, /*can_reshape=*/false);
788 if( !i ) break;
789 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
790 k = i;
791 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
792 }
793 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
794
795
796 // If brand new node, make space in type array.
797 ensure_type_or_null(k);
798
799 // Since I just called 'Value' to compute the set of run-time values
800 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
801 // cache Value. Later requests for the local phase->type of this Node can
802 // use the cached Value instead of suffering with 'bottom_type'.
803 const Type *t = k->Value(this); // Get runtime Value set
804 assert(t != NULL, "value sanity");
805 if (type_or_null(k) != t) {
806 #ifndef PRODUCT
807 // Do not count initial visit to node as a transformation
808 if (type_or_null(k) == NULL) {
809 inc_new_values();
810 set_progress();
811 }
812 #endif
813 set_type(k, t);
814 // If k is a TypeNode, capture any more-precise type permanently into Node
815 k->raise_bottom_type(t);
816 }
817
818 if( t->singleton() && !k->is_Con() ) {
819 NOT_PRODUCT( set_progress(); )
820 return makecon(t); // Turn into a constant
821 }
822
823 // Now check for Identities
824 Node *i = k->Identity(this); // Look for a nearby replacement
825 if( i != k ) { // Found? Return replacement!
826 NOT_PRODUCT( set_progress(); )
827 return i;
828 }
829
830 // Global Value Numbering
831 i = hash_find_insert(k); // Insert if new
832 if( i && (i != k) ) {
833 // Return the pre-existing node
834 NOT_PRODUCT( set_progress(); )
835 return i;
836 }
837
838 // Return Idealized original
839 return k;
840 }
841
842 bool PhaseGVN::is_dominator_helper(Node *d, Node *n, bool linear_only) {
843 if (d->is_top() || n->is_top()) {
844 return false;
845 }
846 assert(d->is_CFG() && n->is_CFG(), "must have CFG nodes");
847 int i = 0;
848 while (d != n) {
849 n = IfNode::up_one_dom(n, linear_only);
850 i++;
851 if (n == NULL || i >= 10) {
852 return false;
853 }
854 }
855 return true;
856 }
857
858 #ifdef ASSERT
859 //------------------------------dead_loop_check--------------------------------
860 // Check for a simple dead loop when a data node references itself directly
861 // or through an other data node excluding cons and phis.
862 void PhaseGVN::dead_loop_check( Node *n ) {
863 // Phi may reference itself in a loop
864 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
865 // Do 2 levels check and only data inputs.
866 bool no_dead_loop = true;
867 uint cnt = n->req();
868 for (uint i = 1; i < cnt && no_dead_loop; i++) {
869 Node *in = n->in(i);
870 if (in == n) {
871 no_dead_loop = false;
872 } else if (in != NULL && !in->is_dead_loop_safe()) {
873 uint icnt = in->req();
874 for (uint j = 1; j < icnt && no_dead_loop; j++) {
875 if (in->in(j) == n || in->in(j) == in)
876 no_dead_loop = false;
877 }
878 }
879 }
880 if (!no_dead_loop) n->dump(3);
881 assert(no_dead_loop, "dead loop detected");
882 }
883 }
884 #endif
885
886 //=============================================================================
887 //------------------------------PhaseIterGVN-----------------------------------
888 // Initialize hash table to fresh and clean for +VerifyOpto
889 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ),
890 _stack(C->live_nodes() >> 1),
891 _delay_transform(false) {
892 }
893
894 //------------------------------PhaseIterGVN-----------------------------------
895 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
896 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
897 _worklist( igvn->_worklist ),
898 _stack( igvn->_stack ),
899 _delay_transform(igvn->_delay_transform)
900 {
901 }
902
903 //------------------------------PhaseIterGVN-----------------------------------
904 // Initialize with previous PhaseGVN info from Parser
905 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
906 _worklist(*C->for_igvn()),
907 // TODO: Before incremental inlining it was allocated only once and it was fine. Now that
908 // the constructor is used in incremental inlining, this consumes too much memory:
909 // _stack(C->live_nodes() >> 1),
910 // So, as a band-aid, we replace this by:
911 _stack(C->comp_arena(), 32),
912 _delay_transform(false)
913 {
914 uint max;
915
916 // Dead nodes in the hash table inherited from GVN were not treated as
917 // roots during def-use info creation; hence they represent an invisible
918 // use. Clear them out.
919 max = _table.size();
920 for( uint i = 0; i < max; ++i ) {
921 Node *n = _table.at(i);
922 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
923 if( n->is_top() ) continue;
924 assert( false, "Parse::remove_useless_nodes missed this node");
925 hash_delete(n);
926 }
927 }
928
929 // Any Phis or Regions on the worklist probably had uses that could not
930 // make more progress because the uses were made while the Phis and Regions
931 // were in half-built states. Put all uses of Phis and Regions on worklist.
932 max = _worklist.size();
933 for( uint j = 0; j < max; j++ ) {
934 Node *n = _worklist.at(j);
935 uint uop = n->Opcode();
936 if( uop == Op_Phi || uop == Op_Region ||
937 n->is_Type() ||
938 n->is_Mem() )
939 add_users_to_worklist(n);
940 }
941 }
942
943 /**
944 * Initialize worklist for each node.
945 */
946 void PhaseIterGVN::init_worklist(Node* first) {
947 Unique_Node_List to_process;
948 to_process.push(first);
949
950 while (to_process.size() > 0) {
951 Node* n = to_process.pop();
952 if (!_worklist.member(n)) {
953 _worklist.push(n);
954
955 uint cnt = n->req();
956 for(uint i = 0; i < cnt; i++) {
957 Node* m = n->in(i);
958 if (m != NULL) {
959 to_process.push(m);
960 }
961 }
962 }
963 }
964 }
965
966 #ifndef PRODUCT
967 void PhaseIterGVN::verify_step(Node* n) {
968 if (VerifyIterativeGVN) {
969 _verify_window[_verify_counter % _verify_window_size] = n;
970 ++_verify_counter;
971 ResourceMark rm;
972 ResourceArea* area = Thread::current()->resource_area();
973 VectorSet old_space(area), new_space(area);
974 if (C->unique() < 1000 ||
975 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
976 ++_verify_full_passes;
977 Node::verify_recur(C->root(), -1, old_space, new_space);
978 }
979 const int verify_depth = 4;
980 for ( int i = 0; i < _verify_window_size; i++ ) {
981 Node* n = _verify_window[i];
982 if ( n == NULL ) continue;
983 if( n->in(0) == NodeSentinel ) { // xform_idom
984 _verify_window[i] = n->in(1);
985 --i; continue;
986 }
987 // Typical fanout is 1-2, so this call visits about 6 nodes.
988 Node::verify_recur(n, verify_depth, old_space, new_space);
989 }
990 }
991 }
992
993 void PhaseIterGVN::trace_PhaseIterGVN(Node* n, Node* nn, const Type* oldtype) {
994 if (TraceIterativeGVN) {
995 uint wlsize = _worklist.size();
996 const Type* newtype = type_or_null(n);
997 if (nn != n) {
998 // print old node
999 tty->print("< ");
1000 if (oldtype != newtype && oldtype != NULL) {
1001 oldtype->dump();
1002 }
1003 do { tty->print("\t"); } while (tty->position() < 16);
1004 tty->print("<");
1005 n->dump();
1006 }
1007 if (oldtype != newtype || nn != n) {
1008 // print new node and/or new type
1009 if (oldtype == NULL) {
1010 tty->print("* ");
1011 } else if (nn != n) {
1012 tty->print("> ");
1013 } else {
1014 tty->print("= ");
1015 }
1016 if (newtype == NULL) {
1017 tty->print("null");
1018 } else {
1019 newtype->dump();
1020 }
1021 do { tty->print("\t"); } while (tty->position() < 16);
1022 nn->dump();
1023 }
1024 if (Verbose && wlsize < _worklist.size()) {
1025 tty->print(" Push {");
1026 while (wlsize != _worklist.size()) {
1027 Node* pushed = _worklist.at(wlsize++);
1028 tty->print(" %d", pushed->_idx);
1029 }
1030 tty->print_cr(" }");
1031 }
1032 if (nn != n) {
1033 // ignore n, it might be subsumed
1034 verify_step((Node*) NULL);
1035 }
1036 }
1037 }
1038
1039 void PhaseIterGVN::init_verifyPhaseIterGVN() {
1040 _verify_counter = 0;
1041 _verify_full_passes = 0;
1042 for (int i = 0; i < _verify_window_size; i++) {
1043 _verify_window[i] = NULL;
1044 }
1045 #ifdef ASSERT
1046 // Verify that all modified nodes are on _worklist
1047 Unique_Node_List* modified_list = C->modified_nodes();
1048 while (modified_list != NULL && modified_list->size()) {
1049 Node* n = modified_list->pop();
1050 if (n->outcnt() != 0 && !n->is_Con() && !_worklist.member(n)) {
1051 n->dump();
1052 assert(false, "modified node is not on IGVN._worklist");
1053 }
1054 }
1055 #endif
1056 }
1057
1058 void PhaseIterGVN::verify_PhaseIterGVN() {
1059 #ifdef ASSERT
1060 // Verify nodes with changed inputs.
1061 Unique_Node_List* modified_list = C->modified_nodes();
1062 while (modified_list != NULL && modified_list->size()) {
1063 Node* n = modified_list->pop();
1064 if (n->outcnt() != 0 && !n->is_Con()) { // skip dead and Con nodes
1065 n->dump();
1066 assert(false, "modified node was not processed by IGVN.transform_old()");
1067 }
1068 }
1069 #endif
1070
1071 C->verify_graph_edges();
1072 if( VerifyOpto && allow_progress() ) {
1073 // Must turn off allow_progress to enable assert and break recursion
1074 C->root()->verify();
1075 { // Check if any progress was missed using IterGVN
1076 // Def-Use info enables transformations not attempted in wash-pass
1077 // e.g. Region/Phi cleanup, ...
1078 // Null-check elision -- may not have reached fixpoint
1079 // do not propagate to dominated nodes
1080 ResourceMark rm;
1081 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
1082 // Fill worklist completely
1083 igvn2.init_worklist(C->root());
1084
1085 igvn2.set_allow_progress(false);
1086 igvn2.optimize();
1087 igvn2.set_allow_progress(true);
1088 }
1089 }
1090 if (VerifyIterativeGVN && PrintOpto) {
1091 if (_verify_counter == _verify_full_passes) {
1092 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
1093 (int) _verify_full_passes);
1094 } else {
1095 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
1096 (int) _verify_counter, (int) _verify_full_passes);
1097 }
1098 }
1099
1100 #ifdef ASSERT
1101 while (modified_list->size()) {
1102 Node* n = modified_list->pop();
1103 n->dump();
1104 assert(false, "VerifyIterativeGVN: new modified node was added");
1105 }
1106 #endif
1107 }
1108 #endif /* PRODUCT */
1109
1110 #ifdef ASSERT
1111 /**
1112 * Dumps information that can help to debug the problem. A debug
1113 * build fails with an assert.
1114 */
1115 void PhaseIterGVN::dump_infinite_loop_info(Node* n) {
1116 n->dump(4);
1117 _worklist.dump();
1118 assert(false, "infinite loop in PhaseIterGVN::optimize");
1119 }
1120
1121 /**
1122 * Prints out information about IGVN if the 'verbose' option is used.
1123 */
1124 void PhaseIterGVN::trace_PhaseIterGVN_verbose(Node* n, int num_processed) {
1125 if (TraceIterativeGVN && Verbose) {
1126 tty->print(" Pop ");
1127 n->dump();
1128 if ((num_processed % 100) == 0) {
1129 _worklist.print_set();
1130 }
1131 }
1132 }
1133 #endif /* ASSERT */
1134
1135 void PhaseIterGVN::optimize() {
1136 DEBUG_ONLY(uint num_processed = 0;)
1137 NOT_PRODUCT(init_verifyPhaseIterGVN();)
1138
1139 uint loop_count = 0;
1140 // Pull from worklist and transform the node. If the node has changed,
1141 // update edge info and put uses on worklist.
1142 while(_worklist.size()) {
1143 if (C->check_node_count(NodeLimitFudgeFactor * 2, "Out of nodes")) {
1144 return;
1145 }
1146 Node* n = _worklist.pop();
1147 if (++loop_count >= K * C->live_nodes()) {
1148 DEBUG_ONLY(dump_infinite_loop_info(n);)
1149 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
1150 return;
1151 }
1152 DEBUG_ONLY(trace_PhaseIterGVN_verbose(n, num_processed++);)
1153 if (n->outcnt() != 0) {
1154 NOT_PRODUCT(const Type* oldtype = type_or_null(n));
1155 // Do the transformation
1156 Node* nn = transform_old(n);
1157 NOT_PRODUCT(trace_PhaseIterGVN(n, nn, oldtype);)
1158 } else if (!n->is_top()) {
1159 remove_dead_node(n);
1160 }
1161 }
1162 NOT_PRODUCT(verify_PhaseIterGVN();)
1163 }
1164
1165
1166 /**
1167 * Register a new node with the optimizer. Update the types array, the def-use
1168 * info. Put on worklist.
1169 */
1170 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
1171 set_type_bottom(n);
1172 _worklist.push(n);
1173 if (orig != NULL) C->copy_node_notes_to(n, orig);
1174 return n;
1175 }
1176
1177 //------------------------------transform--------------------------------------
1178 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
1179 Node *PhaseIterGVN::transform( Node *n ) {
1180 if (_delay_transform) {
1181 // Register the node but don't optimize for now
1182 register_new_node_with_optimizer(n);
1183 return n;
1184 }
1185
1186 // If brand new node, make space in type array, and give it a type.
1187 ensure_type_or_null(n);
1188 if (type_or_null(n) == NULL) {
1189 set_type_bottom(n);
1190 }
1191
1192 return transform_old(n);
1193 }
1194
1195 Node *PhaseIterGVN::transform_old(Node* n) {
1196 DEBUG_ONLY(uint loop_count = 0;);
1197 NOT_PRODUCT(set_transforms());
1198
1199 // Remove 'n' from hash table in case it gets modified
1200 _table.hash_delete(n);
1201 if (VerifyIterativeGVN) {
1202 assert(!_table.find_index(n->_idx), "found duplicate entry in table");
1203 }
1204
1205 // Apply the Ideal call in a loop until it no longer applies
1206 Node* k = n;
1207 DEBUG_ONLY(dead_loop_check(k);)
1208 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1209 C->remove_modified_node(k);
1210 Node* i = k->Ideal(this, /*can_reshape=*/true);
1211 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1212 #ifndef PRODUCT
1213 verify_step(k);
1214 if (i && VerifyOpto ) {
1215 if (!allow_progress()) {
1216 if (i->is_Add() && (i->outcnt() == 1)) {
1217 // Switched input to left side because this is the only use
1218 } else if (i->is_If() && (i->in(0) == NULL)) {
1219 // This IF is dead because it is dominated by an equivalent IF When
1220 // dominating if changed, info is not propagated sparsely to 'this'
1221 // Propagating this info further will spuriously identify other
1222 // progress.
1223 return i;
1224 } else
1225 set_progress();
1226 } else {
1227 set_progress();
1228 }
1229 }
1230 #endif
1231
1232 while (i != NULL) {
1233 #ifdef ASSERT
1234 if (loop_count >= K) {
1235 dump_infinite_loop_info(i);
1236 }
1237 loop_count++;
1238 #endif
1239 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1240 // Made a change; put users of original Node on worklist
1241 add_users_to_worklist(k);
1242 // Replacing root of transform tree?
1243 if (k != i) {
1244 // Make users of old Node now use new.
1245 subsume_node(k, i);
1246 k = i;
1247 }
1248 DEBUG_ONLY(dead_loop_check(k);)
1249 // Try idealizing again
1250 DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1251 C->remove_modified_node(k);
1252 i = k->Ideal(this, /*can_reshape=*/true);
1253 assert(i != k || is_new || (i->outcnt() > 0), "don't return dead nodes");
1254 #ifndef PRODUCT
1255 verify_step(k);
1256 if (i && VerifyOpto) {
1257 set_progress();
1258 }
1259 #endif
1260 }
1261
1262 // If brand new node, make space in type array.
1263 ensure_type_or_null(k);
1264
1265 // See what kind of values 'k' takes on at runtime
1266 const Type* t = k->Value(this);
1267 assert(t != NULL, "value sanity");
1268
1269 // Since I just called 'Value' to compute the set of run-time values
1270 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1271 // cache Value. Later requests for the local phase->type of this Node can
1272 // use the cached Value instead of suffering with 'bottom_type'.
1273 if (type_or_null(k) != t) {
1274 #ifndef PRODUCT
1275 inc_new_values();
1276 set_progress();
1277 #endif
1278 set_type(k, t);
1279 // If k is a TypeNode, capture any more-precise type permanently into Node
1280 k->raise_bottom_type(t);
1281 // Move users of node to worklist
1282 add_users_to_worklist(k);
1283 }
1284 // If 'k' computes a constant, replace it with a constant
1285 if (t->singleton() && !k->is_Con()) {
1286 NOT_PRODUCT(set_progress();)
1287 Node* con = makecon(t); // Make a constant
1288 add_users_to_worklist(k);
1289 subsume_node(k, con); // Everybody using k now uses con
1290 return con;
1291 }
1292
1293 // Now check for Identities
1294 i = k->Identity(this); // Look for a nearby replacement
1295 if (i != k) { // Found? Return replacement!
1296 NOT_PRODUCT(set_progress();)
1297 add_users_to_worklist(k);
1298 subsume_node(k, i); // Everybody using k now uses i
1299 return i;
1300 }
1301
1302 // Global Value Numbering
1303 i = hash_find_insert(k); // Check for pre-existing node
1304 if (i && (i != k)) {
1305 // Return the pre-existing node if it isn't dead
1306 NOT_PRODUCT(set_progress();)
1307 add_users_to_worklist(k);
1308 subsume_node(k, i); // Everybody using k now uses i
1309 return i;
1310 }
1311
1312 // Return Idealized original
1313 return k;
1314 }
1315
1316 //---------------------------------saturate------------------------------------
1317 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1318 const Type* limit_type) const {
1319 return new_type->narrow(old_type);
1320 }
1321
1322 //------------------------------remove_globally_dead_node----------------------
1323 // Kill a globally dead Node. All uses are also globally dead and are
1324 // aggressively trimmed.
1325 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1326 enum DeleteProgress {
1327 PROCESS_INPUTS,
1328 PROCESS_OUTPUTS
1329 };
1330 assert(_stack.is_empty(), "not empty");
1331 _stack.push(dead, PROCESS_INPUTS);
1332
1333 while (_stack.is_nonempty()) {
1334 dead = _stack.node();
1335 uint progress_state = _stack.index();
1336 assert(dead != C->root(), "killing root, eh?");
1337 assert(!dead->is_top(), "add check for top when pushing");
1338 NOT_PRODUCT( set_progress(); )
1339 if (progress_state == PROCESS_INPUTS) {
1340 // After following inputs, continue to outputs
1341 _stack.set_index(PROCESS_OUTPUTS);
1342 if (!dead->is_Con()) { // Don't kill cons but uses
1343 bool recurse = false;
1344 // Remove from hash table
1345 _table.hash_delete( dead );
1346 // Smash all inputs to 'dead', isolating him completely
1347 for (uint i = 0; i < dead->req(); i++) {
1348 Node *in = dead->in(i);
1349 if (in != NULL && in != C->top()) { // Points to something?
1350 int nrep = dead->replace_edge(in, NULL); // Kill edges
1351 assert((nrep > 0), "sanity");
1352 if (in->outcnt() == 0) { // Made input go dead?
1353 _stack.push(in, PROCESS_INPUTS); // Recursively remove
1354 recurse = true;
1355 } else if (in->outcnt() == 1 &&
1356 in->has_special_unique_user()) {
1357 _worklist.push(in->unique_out());
1358 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1359 if (in->Opcode() == Op_Region) {
1360 _worklist.push(in);
1361 } else if (in->is_Store()) {
1362 DUIterator_Fast imax, i = in->fast_outs(imax);
1363 _worklist.push(in->fast_out(i));
1364 i++;
1365 if (in->outcnt() == 2) {
1366 _worklist.push(in->fast_out(i));
1367 i++;
1368 }
1369 assert(!(i < imax), "sanity");
1370 }
1371 }
1372 if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory &&
1373 in->is_Proj() && in->in(0) != NULL && in->in(0)->is_Initialize()) {
1374 // A Load that directly follows an InitializeNode is
1375 // going away. The Stores that follow are candidates
1376 // again to be captured by the InitializeNode.
1377 for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) {
1378 Node *n = in->fast_out(j);
1379 if (n->is_Store()) {
1380 _worklist.push(n);
1381 }
1382 }
1383 }
1384 } // if (in != NULL && in != C->top())
1385 } // for (uint i = 0; i < dead->req(); i++)
1386 if (recurse) {
1387 continue;
1388 }
1389 } // if (!dead->is_Con())
1390 } // if (progress_state == PROCESS_INPUTS)
1391
1392 // Aggressively kill globally dead uses
1393 // (Rather than pushing all the outs at once, we push one at a time,
1394 // plus the parent to resume later, because of the indefinite number
1395 // of edge deletions per loop trip.)
1396 if (dead->outcnt() > 0) {
1397 // Recursively remove output edges
1398 _stack.push(dead->raw_out(0), PROCESS_INPUTS);
1399 } else {
1400 // Finished disconnecting all input and output edges.
1401 _stack.pop();
1402 // Remove dead node from iterative worklist
1403 _worklist.remove(dead);
1404 C->remove_modified_node(dead);
1405 // Constant node that has no out-edges and has only one in-edge from
1406 // root is usually dead. However, sometimes reshaping walk makes
1407 // it reachable by adding use edges. So, we will NOT count Con nodes
1408 // as dead to be conservative about the dead node count at any
1409 // given time.
1410 if (!dead->is_Con()) {
1411 C->record_dead_node(dead->_idx);
1412 }
1413 if (dead->is_macro()) {
1414 C->remove_macro_node(dead);
1415 }
1416 if (dead->is_expensive()) {
1417 C->remove_expensive_node(dead);
1418 }
1419 CastIINode* cast = dead->isa_CastII();
1420 if (cast != NULL && cast->has_range_check()) {
1421 C->remove_range_check_cast(cast);
1422 }
1423 if (dead->is_ValueTypePtr()) {
1424 C->remove_value_type_ptr(dead->as_ValueTypePtr());
1425 }
1426 }
1427 } // while (_stack.is_nonempty())
1428 }
1429
1430 //------------------------------subsume_node-----------------------------------
1431 // Remove users from node 'old' and add them to node 'nn'.
1432 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1433 assert( old != hash_find(old), "should already been removed" );
1434 assert( old != C->top(), "cannot subsume top node");
1435 // Copy debug or profile information to the new version:
1436 C->copy_node_notes_to(nn, old);
1437 // Move users of node 'old' to node 'nn'
1438 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1439 Node* use = old->last_out(i); // for each use...
1440 // use might need re-hashing (but it won't if it's a new node)
1441 rehash_node_delayed(use);
1442 // Update use-def info as well
1443 // We remove all occurrences of old within use->in,
1444 // so as to avoid rehashing any node more than once.
1445 // The hash table probe swamps any outer loop overhead.
1446 uint num_edges = 0;
1447 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1448 if (use->in(j) == old) {
1449 use->set_req(j, nn);
1450 ++num_edges;
1451 }
1452 }
1453 i -= num_edges; // we deleted 1 or more copies of this edge
1454 }
1455
1456 // Search for instance field data PhiNodes in the same region pointing to the old
1457 // memory PhiNode and update their instance memory ids to point to the new node.
1458 if (old->is_Phi() && old->as_Phi()->type()->has_memory() && old->in(0) != NULL) {
1459 Node* region = old->in(0);
1460 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1461 PhiNode* phi = region->fast_out(i)->isa_Phi();
1462 if (phi != NULL && phi->inst_mem_id() == (int)old->_idx) {
1463 phi->set_inst_mem_id((int)nn->_idx);
1464 }
1465 }
1466 }
1467
1468 // Smash all inputs to 'old', isolating him completely
1469 Node *temp = new Node(1);
1470 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1471 remove_dead_node( old );
1472 temp->del_req(0); // Yank bogus edge
1473 #ifndef PRODUCT
1474 if( VerifyIterativeGVN ) {
1475 for ( int i = 0; i < _verify_window_size; i++ ) {
1476 if ( _verify_window[i] == old )
1477 _verify_window[i] = nn;
1478 }
1479 }
1480 #endif
1481 _worklist.remove(temp); // this can be necessary
1482 temp->destruct(); // reuse the _idx of this little guy
1483 }
1484
1485 void PhaseIterGVN::replace_in_uses(Node* n, Node* m) {
1486 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1487 Node* u = n->fast_out(i);
1488 if (u != n) {
1489 rehash_node_delayed(u);
1490 int nb = u->replace_edge(n, m);
1491 --i, imax -= nb;
1492 }
1493 }
1494 }
1495
1496 //------------------------------add_users_to_worklist--------------------------
1497 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1498 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1499 _worklist.push(n->fast_out(i)); // Push on worklist
1500 }
1501 }
1502
1503 // Return counted loop Phi if as a counted loop exit condition, cmp
1504 // compares the the induction variable with n
1505 static PhiNode* countedloop_phi_from_cmp(CmpINode* cmp, Node* n) {
1506 for (DUIterator_Fast imax, i = cmp->fast_outs(imax); i < imax; i++) {
1507 Node* bol = cmp->fast_out(i);
1508 for (DUIterator_Fast i2max, i2 = bol->fast_outs(i2max); i2 < i2max; i2++) {
1509 Node* iff = bol->fast_out(i2);
1510 if (iff->is_CountedLoopEnd()) {
1511 CountedLoopEndNode* cle = iff->as_CountedLoopEnd();
1512 if (cle->limit() == n) {
1513 PhiNode* phi = cle->phi();
1514 if (phi != NULL) {
1515 return phi;
1516 }
1517 }
1518 }
1519 }
1520 }
1521 return NULL;
1522 }
1523
1524 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1525 add_users_to_worklist0(n);
1526
1527 // Move users of node to worklist
1528 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1529 Node* use = n->fast_out(i); // Get use
1530
1531 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1532 use->is_Store() ) // Enable store/load same address
1533 add_users_to_worklist0(use);
1534
1535 // If we changed the receiver type to a call, we need to revisit
1536 // the Catch following the call. It's looking for a non-NULL
1537 // receiver to know when to enable the regular fall-through path
1538 // in addition to the NullPtrException path.
1539 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1540 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control);
1541 if (p != NULL) {
1542 add_users_to_worklist0(p);
1543 }
1544 }
1545
1546 uint use_op = use->Opcode();
1547 if(use->is_Cmp()) { // Enable CMP/BOOL optimization
1548 add_users_to_worklist(use); // Put Bool on worklist
1549 if (use->outcnt() > 0) {
1550 Node* bol = use->raw_out(0);
1551 if (bol->outcnt() > 0) {
1552 Node* iff = bol->raw_out(0);
1553 if (iff->outcnt() == 2) {
1554 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1555 // phi merging either 0 or 1 onto the worklist
1556 Node* ifproj0 = iff->raw_out(0);
1557 Node* ifproj1 = iff->raw_out(1);
1558 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1559 Node* region0 = ifproj0->raw_out(0);
1560 Node* region1 = ifproj1->raw_out(0);
1561 if( region0 == region1 )
1562 add_users_to_worklist0(region0);
1563 }
1564 }
1565 }
1566 }
1567 if (use_op == Op_CmpI) {
1568 Node* phi = countedloop_phi_from_cmp((CmpINode*)use, n);
1569 if (phi != NULL) {
1570 // If an opaque node feeds into the limit condition of a
1571 // CountedLoop, we need to process the Phi node for the
1572 // induction variable when the opaque node is removed:
1573 // the range of values taken by the Phi is now known and
1574 // so its type is also known.
1575 _worklist.push(phi);
1576 }
1577 Node* in1 = use->in(1);
1578 for (uint i = 0; i < in1->outcnt(); i++) {
1579 if (in1->raw_out(i)->Opcode() == Op_CastII) {
1580 Node* castii = in1->raw_out(i);
1581 if (castii->in(0) != NULL && castii->in(0)->in(0) != NULL && castii->in(0)->in(0)->is_If()) {
1582 Node* ifnode = castii->in(0)->in(0);
1583 if (ifnode->in(1) != NULL && ifnode->in(1)->is_Bool() && ifnode->in(1)->in(1) == use) {
1584 // Reprocess a CastII node that may depend on an
1585 // opaque node value when the opaque node is
1586 // removed. In case it carries a dependency we can do
1587 // a better job of computing its type.
1588 _worklist.push(castii);
1589 }
1590 }
1591 }
1592 }
1593 }
1594 }
1595
1596 // If changed Cast input, check Phi users for simple cycles
1597 if (use->is_ConstraintCast()) {
1598 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1599 Node* u = use->fast_out(i2);
1600 if (u->is_Phi())
1601 _worklist.push(u);
1602 }
1603 }
1604 // If changed LShift inputs, check RShift users for useless sign-ext
1605 if( use_op == Op_LShiftI ) {
1606 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1607 Node* u = use->fast_out(i2);
1608 if (u->Opcode() == Op_RShiftI)
1609 _worklist.push(u);
1610 }
1611 }
1612 // If changed AddI/SubI inputs, check CmpU for range check optimization.
1613 if (use_op == Op_AddI || use_op == Op_SubI) {
1614 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1615 Node* u = use->fast_out(i2);
1616 if (u->is_Cmp() && (u->Opcode() == Op_CmpU)) {
1617 _worklist.push(u);
1618 }
1619 }
1620 }
1621 // If changed AddP inputs, check Stores for loop invariant
1622 if( use_op == Op_AddP ) {
1623 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1624 Node* u = use->fast_out(i2);
1625 if (u->is_Mem())
1626 _worklist.push(u);
1627 }
1628 }
1629 // If changed initialization activity, check dependent Stores
1630 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1631 InitializeNode* init = use->as_Allocate()->initialization();
1632 if (init != NULL) {
1633 Node* imem = init->proj_out(TypeFunc::Memory);
1634 if (imem != NULL) add_users_to_worklist0(imem);
1635 }
1636 }
1637 if (use_op == Op_Initialize) {
1638 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory);
1639 if (imem != NULL) add_users_to_worklist0(imem);
1640 }
1641 if (use_op == Op_CastP2X) {
1642 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1643 Node* u = use->fast_out(i2);
1644 if (u->Opcode() == Op_AndX) {
1645 _worklist.push(u);
1646 }
1647 }
1648 }
1649 }
1650 }
1651
1652 /**
1653 * Remove the speculative part of all types that we know of
1654 */
1655 void PhaseIterGVN::remove_speculative_types() {
1656 assert(UseTypeSpeculation, "speculation is off");
1657 for (uint i = 0; i < _types.Size(); i++) {
1658 const Type* t = _types.fast_lookup(i);
1659 if (t != NULL) {
1660 _types.map(i, t->remove_speculative());
1661 }
1662 }
1663 _table.check_no_speculative_types();
1664 }
1665
1666 //=============================================================================
1667 #ifndef PRODUCT
1668 uint PhaseCCP::_total_invokes = 0;
1669 uint PhaseCCP::_total_constants = 0;
1670 #endif
1671 //------------------------------PhaseCCP---------------------------------------
1672 // Conditional Constant Propagation, ala Wegman & Zadeck
1673 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1674 NOT_PRODUCT( clear_constants(); )
1675 assert( _worklist.size() == 0, "" );
1676 // Clear out _nodes from IterGVN. Must be clear to transform call.
1677 _nodes.clear(); // Clear out from IterGVN
1678 analyze();
1679 }
1680
1681 #ifndef PRODUCT
1682 //------------------------------~PhaseCCP--------------------------------------
1683 PhaseCCP::~PhaseCCP() {
1684 inc_invokes();
1685 _total_constants += count_constants();
1686 }
1687 #endif
1688
1689
1690 #ifdef ASSERT
1691 static bool ccp_type_widens(const Type* t, const Type* t0) {
1692 assert(t->meet(t0) == t, "Not monotonic");
1693 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1694 case Type::Int:
1695 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1696 break;
1697 case Type::Long:
1698 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1699 break;
1700 }
1701 return true;
1702 }
1703 #endif //ASSERT
1704
1705 //------------------------------analyze----------------------------------------
1706 void PhaseCCP::analyze() {
1707 // Initialize all types to TOP, optimistic analysis
1708 for (int i = C->unique() - 1; i >= 0; i--) {
1709 _types.map(i,Type::TOP);
1710 }
1711
1712 // Push root onto worklist
1713 Unique_Node_List worklist;
1714 worklist.push(C->root());
1715
1716 // Pull from worklist; compute new value; push changes out.
1717 // This loop is the meat of CCP.
1718 while( worklist.size() ) {
1719 Node *n = worklist.pop();
1720 const Type *t = n->Value(this);
1721 if (t != type(n)) {
1722 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1723 #ifndef PRODUCT
1724 if( TracePhaseCCP ) {
1725 t->dump();
1726 do { tty->print("\t"); } while (tty->position() < 16);
1727 n->dump();
1728 }
1729 #endif
1730 set_type(n, t);
1731 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1732 Node* m = n->fast_out(i); // Get user
1733 if (m->is_Region()) { // New path to Region? Must recheck Phis too
1734 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1735 Node* p = m->fast_out(i2); // Propagate changes to uses
1736 if (p->bottom_type() != type(p)) { // If not already bottomed out
1737 worklist.push(p); // Propagate change to user
1738 }
1739 }
1740 }
1741 // If we changed the receiver type to a call, we need to revisit
1742 // the Catch following the call. It's looking for a non-NULL
1743 // receiver to know when to enable the regular fall-through path
1744 // in addition to the NullPtrException path
1745 if (m->is_Call()) {
1746 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1747 Node* p = m->fast_out(i2); // Propagate changes to uses
1748 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1) {
1749 worklist.push(p->unique_out());
1750 }
1751 }
1752 }
1753 if (m->bottom_type() != type(m)) { // If not already bottomed out
1754 worklist.push(m); // Propagate change to user
1755 }
1756
1757 // CmpU nodes can get their type information from two nodes up in the
1758 // graph (instead of from the nodes immediately above). Make sure they
1759 // are added to the worklist if nodes they depend on are updated, since
1760 // they could be missed and get wrong types otherwise.
1761 uint m_op = m->Opcode();
1762 if (m_op == Op_AddI || m_op == Op_SubI) {
1763 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1764 Node* p = m->fast_out(i2); // Propagate changes to uses
1765 if (p->Opcode() == Op_CmpU) {
1766 // Got a CmpU which might need the new type information from node n.
1767 if(p->bottom_type() != type(p)) { // If not already bottomed out
1768 worklist.push(p); // Propagate change to user
1769 }
1770 }
1771 }
1772 }
1773 // If n is used in a counted loop exit condition then the type
1774 // of the counted loop's Phi depends on the type of n. See
1775 // PhiNode::Value().
1776 if (m_op == Op_CmpI) {
1777 PhiNode* phi = countedloop_phi_from_cmp((CmpINode*)m, n);
1778 if (phi != NULL) {
1779 worklist.push(phi);
1780 }
1781 }
1782 if (m_op == Op_CastP2X) {
1783 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1784 Node* u = m->fast_out(i2);
1785 if (u->Opcode() == Op_AndX) {
1786 worklist.push(u);
1787 }
1788 }
1789 }
1790 }
1791 }
1792 }
1793 }
1794
1795 //------------------------------do_transform-----------------------------------
1796 // Top level driver for the recursive transformer
1797 void PhaseCCP::do_transform() {
1798 // Correct leaves of new-space Nodes; they point to old-space.
1799 C->set_root( transform(C->root())->as_Root() );
1800 assert( C->top(), "missing TOP node" );
1801 assert( C->root(), "missing root" );
1802 }
1803
1804 //------------------------------transform--------------------------------------
1805 // Given a Node in old-space, clone him into new-space.
1806 // Convert any of his old-space children into new-space children.
1807 Node *PhaseCCP::transform( Node *n ) {
1808 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1809 if( new_node != NULL )
1810 return new_node; // Been there, done that, return old answer
1811 new_node = transform_once(n); // Check for constant
1812 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1813
1814 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1815 GrowableArray <Node *> trstack(C->live_nodes() >> 1);
1816
1817 trstack.push(new_node); // Process children of cloned node
1818 while ( trstack.is_nonempty() ) {
1819 Node *clone = trstack.pop();
1820 uint cnt = clone->req();
1821 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1822 Node *input = clone->in(i);
1823 if( input != NULL ) { // Ignore NULLs
1824 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1825 if( new_input == NULL ) {
1826 new_input = transform_once(input); // Check for constant
1827 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1828 trstack.push(new_input);
1829 }
1830 assert( new_input == clone->in(i), "insanity check");
1831 }
1832 }
1833 }
1834 return new_node;
1835 }
1836
1837
1838 //------------------------------transform_once---------------------------------
1839 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1840 Node *PhaseCCP::transform_once( Node *n ) {
1841 const Type *t = type(n);
1842 // Constant? Use constant Node instead
1843 if( t->singleton() ) {
1844 Node *nn = n; // Default is to return the original constant
1845 if( t == Type::TOP ) {
1846 // cache my top node on the Compile instance
1847 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1848 C->set_cached_top_node(ConNode::make(Type::TOP));
1849 set_type(C->top(), Type::TOP);
1850 }
1851 nn = C->top();
1852 }
1853 if( !n->is_Con() ) {
1854 if( t != Type::TOP ) {
1855 nn = makecon(t); // ConNode::make(t);
1856 NOT_PRODUCT( inc_constants(); )
1857 } else if( n->is_Region() ) { // Unreachable region
1858 // Note: nn == C->top()
1859 n->set_req(0, NULL); // Cut selfreference
1860 // Eagerly remove dead phis to avoid phis copies creation.
1861 for (DUIterator i = n->outs(); n->has_out(i); i++) {
1862 Node* m = n->out(i);
1863 if( m->is_Phi() ) {
1864 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1865 replace_node(m, nn);
1866 --i; // deleted this phi; rescan starting with next position
1867 }
1868 }
1869 }
1870 replace_node(n,nn); // Update DefUse edges for new constant
1871 }
1872 return nn;
1873 }
1874
1875 // If x is a TypeNode, capture any more-precise type permanently into Node
1876 if (t != n->bottom_type()) {
1877 hash_delete(n); // changing bottom type may force a rehash
1878 n->raise_bottom_type(t);
1879 _worklist.push(n); // n re-enters the hash table via the worklist
1880 }
1881
1882 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1883 switch( n->Opcode() ) {
1884 case Op_FastLock: // Revisit FastLocks for lock coarsening
1885 case Op_If:
1886 case Op_CountedLoopEnd:
1887 case Op_Region:
1888 case Op_Loop:
1889 case Op_CountedLoop:
1890 case Op_Conv2B:
1891 case Op_Opaque1:
1892 case Op_Opaque2:
1893 _worklist.push(n);
1894 break;
1895 default:
1896 break;
1897 }
1898
1899 return n;
1900 }
1901
1902 //---------------------------------saturate------------------------------------
1903 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
1904 const Type* limit_type) const {
1905 const Type* wide_type = new_type->widen(old_type, limit_type);
1906 if (wide_type != new_type) { // did we widen?
1907 // If so, we may have widened beyond the limit type. Clip it back down.
1908 new_type = wide_type->filter(limit_type);
1909 }
1910 return new_type;
1911 }
1912
1913 //------------------------------print_statistics-------------------------------
1914 #ifndef PRODUCT
1915 void PhaseCCP::print_statistics() {
1916 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
1917 }
1918 #endif
1919
1920
1921 //=============================================================================
1922 #ifndef PRODUCT
1923 uint PhasePeephole::_total_peepholes = 0;
1924 #endif
1925 //------------------------------PhasePeephole----------------------------------
1926 // Conditional Constant Propagation, ala Wegman & Zadeck
1927 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
1928 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
1929 NOT_PRODUCT( clear_peepholes(); )
1930 }
1931
1932 #ifndef PRODUCT
1933 //------------------------------~PhasePeephole---------------------------------
1934 PhasePeephole::~PhasePeephole() {
1935 _total_peepholes += count_peepholes();
1936 }
1937 #endif
1938
1939 //------------------------------transform--------------------------------------
1940 Node *PhasePeephole::transform( Node *n ) {
1941 ShouldNotCallThis();
1942 return NULL;
1943 }
1944
1945 //------------------------------do_transform-----------------------------------
1946 void PhasePeephole::do_transform() {
1947 bool method_name_not_printed = true;
1948
1949 // Examine each basic block
1950 for (uint block_number = 1; block_number < _cfg.number_of_blocks(); ++block_number) {
1951 Block* block = _cfg.get_block(block_number);
1952 bool block_not_printed = true;
1953
1954 // and each instruction within a block
1955 uint end_index = block->number_of_nodes();
1956 // block->end_idx() not valid after PhaseRegAlloc
1957 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
1958 Node *n = block->get_node(instruction_index);
1959 if( n->is_Mach() ) {
1960 MachNode *m = n->as_Mach();
1961 int deleted_count = 0;
1962 // check for peephole opportunities
1963 MachNode *m2 = m->peephole(block, instruction_index, _regalloc, deleted_count);
1964 if( m2 != NULL ) {
1965 #ifndef PRODUCT
1966 if( PrintOptoPeephole ) {
1967 // Print method, first time only
1968 if( C->method() && method_name_not_printed ) {
1969 C->method()->print_short_name(); tty->cr();
1970 method_name_not_printed = false;
1971 }
1972 // Print this block
1973 if( Verbose && block_not_printed) {
1974 tty->print_cr("in block");
1975 block->dump();
1976 block_not_printed = false;
1977 }
1978 // Print instructions being deleted
1979 for( int i = (deleted_count - 1); i >= 0; --i ) {
1980 block->get_node(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
1981 }
1982 tty->print_cr("replaced with");
1983 // Print new instruction
1984 m2->format(_regalloc);
1985 tty->print("\n\n");
1986 }
1987 #endif
1988 // Remove old nodes from basic block and update instruction_index
1989 // (old nodes still exist and may have edges pointing to them
1990 // as register allocation info is stored in the allocator using
1991 // the node index to live range mappings.)
1992 uint safe_instruction_index = (instruction_index - deleted_count);
1993 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
1994 block->remove_node( instruction_index );
1995 }
1996 // install new node after safe_instruction_index
1997 block->insert_node(m2, safe_instruction_index + 1);
1998 end_index = block->number_of_nodes() - 1; // Recompute new block size
1999 NOT_PRODUCT( inc_peepholes(); )
2000 }
2001 }
2002 }
2003 }
2004 }
2005
2006 //------------------------------print_statistics-------------------------------
2007 #ifndef PRODUCT
2008 void PhasePeephole::print_statistics() {
2009 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
2010 }
2011 #endif
2012
2013
2014 //=============================================================================
2015 //------------------------------set_req_X--------------------------------------
2016 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
2017 assert( is_not_dead(n), "can not use dead node");
2018 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
2019 Node *old = in(i);
2020 set_req(i, n);
2021
2022 // old goes dead?
2023 if( old ) {
2024 switch (old->outcnt()) {
2025 case 0:
2026 // Put into the worklist to kill later. We do not kill it now because the
2027 // recursive kill will delete the current node (this) if dead-loop exists
2028 if (!old->is_top())
2029 igvn->_worklist.push( old );
2030 break;
2031 case 1:
2032 if( old->is_Store() || old->has_special_unique_user() )
2033 igvn->add_users_to_worklist( old );
2034 break;
2035 case 2:
2036 if( old->is_Store() )
2037 igvn->add_users_to_worklist( old );
2038 if( old->Opcode() == Op_Region )
2039 igvn->_worklist.push(old);
2040 break;
2041 case 3:
2042 if( old->Opcode() == Op_Region ) {
2043 igvn->_worklist.push(old);
2044 igvn->add_users_to_worklist( old );
2045 }
2046 break;
2047 default:
2048 break;
2049 }
2050 }
2051
2052 }
2053
2054 //-------------------------------replace_by-----------------------------------
2055 // Using def-use info, replace one node for another. Follow the def-use info
2056 // to all users of the OLD node. Then make all uses point to the NEW node.
2057 void Node::replace_by(Node *new_node) {
2058 assert(!is_top(), "top node has no DU info");
2059 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
2060 Node* use = last_out(i);
2061 uint uses_found = 0;
2062 for (uint j = 0; j < use->len(); j++) {
2063 if (use->in(j) == this) {
2064 if (j < use->req())
2065 use->set_req(j, new_node);
2066 else use->set_prec(j, new_node);
2067 uses_found++;
2068 }
2069 }
2070 i -= uses_found; // we deleted 1 or more copies of this edge
2071 }
2072 }
2073
2074 //=============================================================================
2075 //-----------------------------------------------------------------------------
2076 void Type_Array::grow( uint i ) {
2077 if( !_max ) {
2078 _max = 1;
2079 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
2080 _types[0] = NULL;
2081 }
2082 uint old = _max;
2083 while( i >= _max ) _max <<= 1; // Double to fit
2084 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
2085 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
2086 }
2087
2088 //------------------------------dump-------------------------------------------
2089 #ifndef PRODUCT
2090 void Type_Array::dump() const {
2091 uint max = Size();
2092 for( uint i = 0; i < max; i++ ) {
2093 if( _types[i] != NULL ) {
2094 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
2095 }
2096 }
2097 }
2098 #endif