1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "opto/block.hpp"
28 #include "opto/callnode.hpp"
29 #include "opto/cfgnode.hpp"
30 #include "opto/connode.hpp"
31 #include "opto/idealGraphPrinter.hpp"
32 #include "opto/loopnode.hpp"
33 #include "opto/machnode.hpp"
34 #include "opto/opcodes.hpp"
35 #include "opto/phaseX.hpp"
36 #include "opto/regalloc.hpp"
37 #include "opto/rootnode.hpp"
38 #if INCLUDE_ALL_GCS
39 #include "gc_implementation/shenandoah/c2/shenandoahSupport.hpp"
40 #endif
41
42 //=============================================================================
43 #define NODE_HASH_MINIMUM_SIZE 255
44 //------------------------------NodeHash---------------------------------------
45 NodeHash::NodeHash(uint est_max_size) :
46 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
47 _a(Thread::current()->resource_area()),
48 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), // (Node**)_a->Amalloc(_max * sizeof(Node*)) ),
49 _inserts(0), _insert_limit( insert_limit() ),
50 _look_probes(0), _lookup_hits(0), _lookup_misses(0),
51 _total_insert_probes(0), _total_inserts(0),
52 _insert_probes(0), _grows(0) {
53 // _sentinel must be in the current node space
54 _sentinel = new (Compile::current()) ProjNode(NULL, TypeFunc::Control);
55 memset(_table,0,sizeof(Node*)*_max);
56 }
57
58 //------------------------------NodeHash---------------------------------------
59 NodeHash::NodeHash(Arena *arena, uint est_max_size) :
60 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
61 _a(arena),
62 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ),
63 _inserts(0), _insert_limit( insert_limit() ),
64 _look_probes(0), _lookup_hits(0), _lookup_misses(0),
65 _delete_probes(0), _delete_hits(0), _delete_misses(0),
66 _total_insert_probes(0), _total_inserts(0),
67 _insert_probes(0), _grows(0) {
68 // _sentinel must be in the current node space
69 _sentinel = new (Compile::current()) ProjNode(NULL, TypeFunc::Control);
70 memset(_table,0,sizeof(Node*)*_max);
71 }
72
73 //------------------------------NodeHash---------------------------------------
74 NodeHash::NodeHash(NodeHash *nh) {
75 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
76 // just copy in all the fields
77 *this = *nh;
78 // nh->_sentinel must be in the current node space
79 }
80
81 void NodeHash::replace_with(NodeHash *nh) {
82 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
83 // just copy in all the fields
84 *this = *nh;
85 // nh->_sentinel must be in the current node space
86 }
87
88 //------------------------------hash_find--------------------------------------
89 // Find in hash table
90 Node *NodeHash::hash_find( const Node *n ) {
91 // ((Node*)n)->set_hash( n->hash() );
92 uint hash = n->hash();
93 if (hash == Node::NO_HASH) {
94 debug_only( _lookup_misses++ );
95 return NULL;
96 }
97 uint key = hash & (_max-1);
98 uint stride = key | 0x01;
99 debug_only( _look_probes++ );
100 Node *k = _table[key]; // Get hashed value
101 if( !k ) { // ?Miss?
102 debug_only( _lookup_misses++ );
103 return NULL; // Miss!
104 }
105
106 int op = n->Opcode();
107 uint req = n->req();
108 while( 1 ) { // While probing hash table
109 if( k->req() == req && // Same count of inputs
110 k->Opcode() == op ) { // Same Opcode
111 for( uint i=0; i<req; i++ )
112 if( n->in(i)!=k->in(i)) // Different inputs?
113 goto collision; // "goto" is a speed hack...
114 if( n->cmp(*k) ) { // Check for any special bits
115 debug_only( _lookup_hits++ );
116 return k; // Hit!
117 }
118 }
119 collision:
120 debug_only( _look_probes++ );
121 key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime
122 k = _table[key]; // Get hashed value
123 if( !k ) { // ?Miss?
124 debug_only( _lookup_misses++ );
125 return NULL; // Miss!
126 }
127 }
128 ShouldNotReachHere();
129 return NULL;
130 }
131
132 //------------------------------hash_find_insert-------------------------------
133 // Find in hash table, insert if not already present
134 // Used to preserve unique entries in hash table
135 Node *NodeHash::hash_find_insert( Node *n ) {
136 // n->set_hash( );
137 uint hash = n->hash();
138 if (hash == Node::NO_HASH) {
139 debug_only( _lookup_misses++ );
140 return NULL;
141 }
142 uint key = hash & (_max-1);
143 uint stride = key | 0x01; // stride must be relatively prime to table siz
144 uint first_sentinel = 0; // replace a sentinel if seen.
145 debug_only( _look_probes++ );
146 Node *k = _table[key]; // Get hashed value
147 if( !k ) { // ?Miss?
148 debug_only( _lookup_misses++ );
149 _table[key] = n; // Insert into table!
150 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
151 check_grow(); // Grow table if insert hit limit
152 return NULL; // Miss!
153 }
154 else if( k == _sentinel ) {
155 first_sentinel = key; // Can insert here
156 }
157
158 int op = n->Opcode();
159 uint req = n->req();
160 while( 1 ) { // While probing hash table
161 if( k->req() == req && // Same count of inputs
162 k->Opcode() == op ) { // Same Opcode
163 for( uint i=0; i<req; i++ )
164 if( n->in(i)!=k->in(i)) // Different inputs?
165 goto collision; // "goto" is a speed hack...
166 if( n->cmp(*k) ) { // Check for any special bits
167 debug_only( _lookup_hits++ );
168 return k; // Hit!
169 }
170 }
171 collision:
172 debug_only( _look_probes++ );
173 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
174 k = _table[key]; // Get hashed value
175 if( !k ) { // ?Miss?
176 debug_only( _lookup_misses++ );
177 key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel?
178 _table[key] = n; // Insert into table!
179 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
180 check_grow(); // Grow table if insert hit limit
181 return NULL; // Miss!
182 }
183 else if( first_sentinel == 0 && k == _sentinel ) {
184 first_sentinel = key; // Can insert here
185 }
186
187 }
188 ShouldNotReachHere();
189 return NULL;
190 }
191
192 //------------------------------hash_insert------------------------------------
193 // Insert into hash table
194 void NodeHash::hash_insert( Node *n ) {
195 // // "conflict" comments -- print nodes that conflict
196 // bool conflict = false;
197 // n->set_hash();
198 uint hash = n->hash();
199 if (hash == Node::NO_HASH) {
200 return;
201 }
202 check_grow();
203 uint key = hash & (_max-1);
204 uint stride = key | 0x01;
205
206 while( 1 ) { // While probing hash table
207 debug_only( _insert_probes++ );
208 Node *k = _table[key]; // Get hashed value
209 if( !k || (k == _sentinel) ) break; // Found a slot
210 assert( k != n, "already inserted" );
211 // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print(" conflict: "); k->dump(); conflict = true; }
212 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
213 }
214 _table[key] = n; // Insert into table!
215 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
216 // if( conflict ) { n->dump(); }
217 }
218
219 //------------------------------hash_delete------------------------------------
220 // Replace in hash table with sentinel
221 bool NodeHash::hash_delete( const Node *n ) {
222 Node *k;
223 uint hash = n->hash();
224 if (hash == Node::NO_HASH) {
225 debug_only( _delete_misses++ );
226 return false;
227 }
228 uint key = hash & (_max-1);
229 uint stride = key | 0x01;
230 debug_only( uint counter = 0; );
231 for( ; /* (k != NULL) && (k != _sentinel) */; ) {
232 debug_only( counter++ );
233 debug_only( _delete_probes++ );
234 k = _table[key]; // Get hashed value
235 if( !k ) { // Miss?
236 debug_only( _delete_misses++ );
237 #ifdef ASSERT
238 if( VerifyOpto ) {
239 for( uint i=0; i < _max; i++ )
240 assert( _table[i] != n, "changed edges with rehashing" );
241 }
242 #endif
243 return false; // Miss! Not in chain
244 }
245 else if( n == k ) {
246 debug_only( _delete_hits++ );
247 _table[key] = _sentinel; // Hit! Label as deleted entry
248 debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table.
249 return true;
250 }
251 else {
252 // collision: move through table with prime offset
253 key = (key + stride/*7*/) & (_max-1);
254 assert( counter <= _insert_limit, "Cycle in hash-table");
255 }
256 }
257 ShouldNotReachHere();
258 return false;
259 }
260
261 //------------------------------round_up---------------------------------------
262 // Round up to nearest power of 2
263 uint NodeHash::round_up( uint x ) {
264 x += (x>>2); // Add 25% slop
265 if( x <16 ) return 16; // Small stuff
266 uint i=16;
267 while( i < x ) i <<= 1; // Double to fit
268 return i; // Return hash table size
269 }
270
271 //------------------------------grow-------------------------------------------
272 // Grow _table to next power of 2 and insert old entries
273 void NodeHash::grow() {
274 // Record old state
275 uint old_max = _max;
276 Node **old_table = _table;
277 // Construct new table with twice the space
278 _grows++;
279 _total_inserts += _inserts;
280 _total_insert_probes += _insert_probes;
281 _inserts = 0;
282 _insert_probes = 0;
283 _max = _max << 1;
284 _table = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) );
285 memset(_table,0,sizeof(Node*)*_max);
286 _insert_limit = insert_limit();
287 // Insert old entries into the new table
288 for( uint i = 0; i < old_max; i++ ) {
289 Node *m = *old_table++;
290 if( !m || m == _sentinel ) continue;
291 debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table.
292 hash_insert(m);
293 }
294 }
295
296 //------------------------------clear------------------------------------------
297 // Clear all entries in _table to NULL but keep storage
298 void NodeHash::clear() {
299 #ifdef ASSERT
300 // Unlock all nodes upon removal from table.
301 for (uint i = 0; i < _max; i++) {
302 Node* n = _table[i];
303 if (!n || n == _sentinel) continue;
304 n->exit_hash_lock();
305 }
306 #endif
307
308 memset( _table, 0, _max * sizeof(Node*) );
309 }
310
311 //-----------------------remove_useless_nodes----------------------------------
312 // Remove useless nodes from value table,
313 // implementation does not depend on hash function
314 void NodeHash::remove_useless_nodes(VectorSet &useful) {
315
316 // Dead nodes in the hash table inherited from GVN should not replace
317 // existing nodes, remove dead nodes.
318 uint max = size();
319 Node *sentinel_node = sentinel();
320 for( uint i = 0; i < max; ++i ) {
321 Node *n = at(i);
322 if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) {
323 debug_only(n->exit_hash_lock()); // Unlock the node when removed
324 _table[i] = sentinel_node; // Replace with placeholder
325 }
326 }
327 }
328
329
330 void NodeHash::check_no_speculative_types() {
331 #ifdef ASSERT
332 uint max = size();
333 Node *sentinel_node = sentinel();
334 for (uint i = 0; i < max; ++i) {
335 Node *n = at(i);
336 if(n != NULL && n != sentinel_node && n->is_Type()) {
337 TypeNode* tn = n->as_Type();
338 const Type* t = tn->type();
339 const Type* t_no_spec = t->remove_speculative();
340 assert(t == t_no_spec, "dead node in hash table or missed node during speculative cleanup");
341 }
342 }
343 #endif
344 }
345
346 #ifndef PRODUCT
347 //------------------------------dump-------------------------------------------
348 // Dump statistics for the hash table
349 void NodeHash::dump() {
350 _total_inserts += _inserts;
351 _total_insert_probes += _insert_probes;
352 if (PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0)) {
353 if (WizardMode) {
354 for (uint i=0; i<_max; i++) {
355 if (_table[i])
356 tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx);
357 }
358 }
359 tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max);
360 tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0);
361 tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses));
362 tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts);
363 // sentinels increase lookup cost, but not insert cost
364 assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function");
365 assert( _inserts+(_inserts>>3) < _max, "table too full" );
366 assert( _inserts*3+100 >= _insert_probes, "bad hash function" );
367 }
368 }
369
370 Node *NodeHash::find_index(uint idx) { // For debugging
371 // Find an entry by its index value
372 for( uint i = 0; i < _max; i++ ) {
373 Node *m = _table[i];
374 if( !m || m == _sentinel ) continue;
375 if( m->_idx == (uint)idx ) return m;
376 }
377 return NULL;
378 }
379 #endif
380
381 #ifdef ASSERT
382 NodeHash::~NodeHash() {
383 // Unlock all nodes upon destruction of table.
384 if (_table != (Node**)badAddress) clear();
385 }
386
387 void NodeHash::operator=(const NodeHash& nh) {
388 // Unlock all nodes upon replacement of table.
389 if (&nh == this) return;
390 if (_table != (Node**)badAddress) clear();
391 memcpy(this, &nh, sizeof(*this));
392 // Do not increment hash_lock counts again.
393 // Instead, be sure we never again use the source table.
394 ((NodeHash*)&nh)->_table = (Node**)badAddress;
395 }
396
397
398 #endif
399
400
401 //=============================================================================
402 //------------------------------PhaseRemoveUseless-----------------------------
403 // 1) Use a breadthfirst walk to collect useful nodes reachable from root.
404 PhaseRemoveUseless::PhaseRemoveUseless(PhaseGVN *gvn, Unique_Node_List *worklist, PhaseNumber phase_num) : Phase(phase_num),
405 _useful(Thread::current()->resource_area()) {
406
407 // Implementation requires 'UseLoopSafepoints == true' and an edge from root
408 // to each SafePointNode at a backward branch. Inserted in add_safepoint().
409 if( !UseLoopSafepoints || !OptoRemoveUseless ) return;
410
411 // Identify nodes that are reachable from below, useful.
412 C->identify_useful_nodes(_useful);
413 // Update dead node list
414 C->update_dead_node_list(_useful);
415
416 // Remove all useless nodes from PhaseValues' recorded types
417 // Must be done before disconnecting nodes to preserve hash-table-invariant
418 gvn->remove_useless_nodes(_useful.member_set());
419
420 // Remove all useless nodes from future worklist
421 worklist->remove_useless_nodes(_useful.member_set());
422
423 // Disconnect 'useless' nodes that are adjacent to useful nodes
424 C->remove_useless_nodes(_useful);
425 }
426
427 //=============================================================================
428 //------------------------------PhaseRenumberLive------------------------------
429 // First, remove useless nodes (equivalent to identifying live nodes).
430 // Then, renumber live nodes.
431 //
432 // The set of live nodes is returned by PhaseRemoveUseless in the _useful structure.
433 // If the number of live nodes is 'x' (where 'x' == _useful.size()), then the
434 // PhaseRenumberLive updates the node ID of each node (the _idx field) with a unique
435 // value in the range [0, x).
436 //
437 // At the end of the PhaseRenumberLive phase, the compiler's count of unique nodes is
438 // updated to 'x' and the list of dead nodes is reset (as there are no dead nodes).
439 //
440 // The PhaseRenumberLive phase updates two data structures with the new node IDs.
441 // (1) The worklist is used by the PhaseIterGVN phase to identify nodes that must be
442 // processed. A new worklist (with the updated node IDs) is returned in 'new_worklist'.
443 // (2) Type information (the field PhaseGVN::_types) maps type information to each
444 // node ID. The mapping is updated to use the new node IDs as well. Updated type
445 // information is returned in PhaseGVN::_types.
446 //
447 // The PhaseRenumberLive phase does not preserve the order of elements in the worklist.
448 //
449 // Other data structures used by the compiler are not updated. The hash table for value
450 // numbering (the field PhaseGVN::_table) is not updated because computing the hash
451 // values is not based on node IDs. The field PhaseGVN::_nodes is not updated either
452 // because it is empty wherever PhaseRenumberLive is used.
453 PhaseRenumberLive::PhaseRenumberLive(PhaseGVN* gvn,
454 Unique_Node_List* worklist, Unique_Node_List* new_worklist,
455 PhaseNumber phase_num) :
456 PhaseRemoveUseless(gvn, worklist, Remove_Useless_And_Renumber_Live) {
457
458 assert(RenumberLiveNodes, "RenumberLiveNodes must be set to true for node renumbering to take place");
459 assert(C->live_nodes() == _useful.size(), "the number of live nodes must match the number of useful nodes");
460 assert(gvn->nodes_size() == 0, "GVN must not contain any nodes at this point");
461
462 uint old_unique_count = C->unique();
463 uint live_node_count = C->live_nodes();
464 uint worklist_size = worklist->size();
465
466 // Storage for the updated type information.
467 Type_Array new_type_array(C->comp_arena());
468
469 // Iterate over the set of live nodes.
470 uint current_idx = 0; // The current new node ID. Incremented after every assignment.
471 for (uint i = 0; i < _useful.size(); i++) {
472 Node* n = _useful.at(i);
473 // Sanity check that fails if we ever decide to execute this phase after EA
474 assert(!n->is_Phi() || n->as_Phi()->inst_mem_id() == -1, "should not be linked to data Phi");
475 const Type* type = gvn->type_or_null(n);
476 new_type_array.map(current_idx, type);
477
478 bool in_worklist = false;
479 if (worklist->member(n)) {
480 in_worklist = true;
481 }
482
483 n->set_idx(current_idx); // Update node ID.
484
485 if (in_worklist) {
486 new_worklist->push(n);
487 }
488
489 current_idx++;
490 }
491
492 assert(worklist_size == new_worklist->size(), "the new worklist must have the same size as the original worklist");
493 assert(live_node_count == current_idx, "all live nodes must be processed");
494
495 // Replace the compiler's type information with the updated type information.
496 gvn->replace_types(new_type_array);
497
498 // Update the unique node count of the compilation to the number of currently live nodes.
499 C->set_unique(live_node_count);
500
501 // Set the dead node count to 0 and reset dead node list.
502 C->reset_dead_node_list();
503 }
504
505
506 //=============================================================================
507 //------------------------------PhaseTransform---------------------------------
508 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
509 _arena(Thread::current()->resource_area()),
510 _nodes(_arena),
511 _types(_arena)
512 {
513 init_con_caches();
514 #ifndef PRODUCT
515 clear_progress();
516 clear_transforms();
517 set_allow_progress(true);
518 #endif
519 // Force allocation for currently existing nodes
520 _types.map(C->unique(), NULL);
521 }
522
523 //------------------------------PhaseTransform---------------------------------
524 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
525 _arena(arena),
526 _nodes(arena),
527 _types(arena)
528 {
529 init_con_caches();
530 #ifndef PRODUCT
531 clear_progress();
532 clear_transforms();
533 set_allow_progress(true);
534 #endif
535 // Force allocation for currently existing nodes
536 _types.map(C->unique(), NULL);
537 }
538
539 //------------------------------PhaseTransform---------------------------------
540 // Initialize with previously generated type information
541 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
542 _arena(pt->_arena),
543 _nodes(pt->_nodes),
544 _types(pt->_types)
545 {
546 init_con_caches();
547 #ifndef PRODUCT
548 clear_progress();
549 clear_transforms();
550 set_allow_progress(true);
551 #endif
552 }
553
554 void PhaseTransform::init_con_caches() {
555 memset(_icons,0,sizeof(_icons));
556 memset(_lcons,0,sizeof(_lcons));
557 memset(_zcons,0,sizeof(_zcons));
558 }
559
560
561 //--------------------------------find_int_type--------------------------------
562 const TypeInt* PhaseTransform::find_int_type(Node* n) {
563 if (n == NULL) return NULL;
564 // Call type_or_null(n) to determine node's type since we might be in
565 // parse phase and call n->Value() may return wrong type.
566 // (For example, a phi node at the beginning of loop parsing is not ready.)
567 const Type* t = type_or_null(n);
568 if (t == NULL) return NULL;
569 return t->isa_int();
570 }
571
572
573 //-------------------------------find_long_type--------------------------------
574 const TypeLong* PhaseTransform::find_long_type(Node* n) {
575 if (n == NULL) return NULL;
576 // (See comment above on type_or_null.)
577 const Type* t = type_or_null(n);
578 if (t == NULL) return NULL;
579 return t->isa_long();
580 }
581
582
583 #ifndef PRODUCT
584 void PhaseTransform::dump_old2new_map() const {
585 _nodes.dump();
586 }
587
588 void PhaseTransform::dump_new( uint nidx ) const {
589 for( uint i=0; i<_nodes.Size(); i++ )
590 if( _nodes[i] && _nodes[i]->_idx == nidx ) {
591 _nodes[i]->dump();
592 tty->cr();
593 tty->print_cr("Old index= %d",i);
594 return;
595 }
596 tty->print_cr("Node %d not found in the new indices", nidx);
597 }
598
599 //------------------------------dump_types-------------------------------------
600 void PhaseTransform::dump_types( ) const {
601 _types.dump();
602 }
603
604 //------------------------------dump_nodes_and_types---------------------------
605 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
606 VectorSet visited(Thread::current()->resource_area());
607 dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
608 }
609
610 //------------------------------dump_nodes_and_types_recur---------------------
611 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
612 if( !n ) return;
613 if( depth == 0 ) return;
614 if( visited.test_set(n->_idx) ) return;
615 for( uint i=0; i<n->len(); i++ ) {
616 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
617 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
618 }
619 n->dump();
620 if (type_or_null(n) != NULL) {
621 tty->print(" "); type(n)->dump(); tty->cr();
622 }
623 }
624
625 #endif
626
627
628 //=============================================================================
629 //------------------------------PhaseValues------------------------------------
630 // Set minimum table size to "255"
631 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
632 NOT_PRODUCT( clear_new_values(); )
633 }
634
635 //------------------------------PhaseValues------------------------------------
636 // Set minimum table size to "255"
637 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
638 _table(&ptv->_table) {
639 NOT_PRODUCT( clear_new_values(); )
640 }
641
642 //------------------------------PhaseValues------------------------------------
643 // Used by +VerifyOpto. Clear out hash table but copy _types array.
644 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
645 _table(ptv->arena(),ptv->_table.size()) {
646 NOT_PRODUCT( clear_new_values(); )
647 }
648
649 //------------------------------~PhaseValues-----------------------------------
650 #ifndef PRODUCT
651 PhaseValues::~PhaseValues() {
652 _table.dump();
653
654 // Statistics for value progress and efficiency
655 if( PrintCompilation && Verbose && WizardMode ) {
656 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
657 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values());
658 if( made_transforms() != 0 ) {
659 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() );
660 } else {
661 tty->cr();
662 }
663 }
664 }
665 #endif
666
667 //------------------------------makecon----------------------------------------
668 ConNode* PhaseTransform::makecon(const Type *t) {
669 assert(t->singleton(), "must be a constant");
670 assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
671 switch (t->base()) { // fast paths
672 case Type::Half:
673 case Type::Top: return (ConNode*) C->top();
674 case Type::Int: return intcon( t->is_int()->get_con() );
675 case Type::Long: return longcon( t->is_long()->get_con() );
676 }
677 if (t->is_zero_type())
678 return zerocon(t->basic_type());
679 return uncached_makecon(t);
680 }
681
682 //--------------------------uncached_makecon-----------------------------------
683 // Make an idealized constant - one of ConINode, ConPNode, etc.
684 ConNode* PhaseValues::uncached_makecon(const Type *t) {
685 assert(t->singleton(), "must be a constant");
686 ConNode* x = ConNode::make(C, t);
687 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
688 if (k == NULL) {
689 set_type(x, t); // Missed, provide type mapping
690 GrowableArray<Node_Notes*>* nna = C->node_note_array();
691 if (nna != NULL) {
692 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
693 loc->clear(); // do not put debug info on constants
694 }
695 } else {
696 x->destruct(); // Hit, destroy duplicate constant
697 x = k; // use existing constant
698 }
699 return x;
700 }
701
702 //------------------------------intcon-----------------------------------------
703 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
704 ConINode* PhaseTransform::intcon(int i) {
705 // Small integer? Check cache! Check that cached node is not dead
706 if (i >= _icon_min && i <= _icon_max) {
707 ConINode* icon = _icons[i-_icon_min];
708 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
709 return icon;
710 }
711 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
712 assert(icon->is_Con(), "");
713 if (i >= _icon_min && i <= _icon_max)
714 _icons[i-_icon_min] = icon; // Cache small integers
715 return icon;
716 }
717
718 //------------------------------longcon----------------------------------------
719 // Fast long constant.
720 ConLNode* PhaseTransform::longcon(jlong l) {
721 // Small integer? Check cache! Check that cached node is not dead
722 if (l >= _lcon_min && l <= _lcon_max) {
723 ConLNode* lcon = _lcons[l-_lcon_min];
724 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
725 return lcon;
726 }
727 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
728 assert(lcon->is_Con(), "");
729 if (l >= _lcon_min && l <= _lcon_max)
730 _lcons[l-_lcon_min] = lcon; // Cache small integers
731 return lcon;
732 }
733
734 //------------------------------zerocon-----------------------------------------
735 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
736 ConNode* PhaseTransform::zerocon(BasicType bt) {
737 assert((uint)bt <= _zcon_max, "domain check");
738 ConNode* zcon = _zcons[bt];
739 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
740 return zcon;
741 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
742 _zcons[bt] = zcon;
743 return zcon;
744 }
745
746
747
748 //=============================================================================
749 //------------------------------transform--------------------------------------
750 // Return a node which computes the same function as this node, but in a
751 // faster or cheaper fashion.
752 Node *PhaseGVN::transform( Node *n ) {
753 return transform_no_reclaim(n);
754 }
755
756 //------------------------------transform--------------------------------------
757 // Return a node which computes the same function as this node, but
758 // in a faster or cheaper fashion.
759 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
760 NOT_PRODUCT( set_transforms(); )
761
762 // Apply the Ideal call in a loop until it no longer applies
763 Node *k = n;
764 NOT_PRODUCT( uint loop_count = 0; )
765 while( 1 ) {
766 Node *i = k->Ideal(this, /*can_reshape=*/false);
767 if( !i ) break;
768 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
769 k = i;
770 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
771 }
772 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
773
774
775 // If brand new node, make space in type array.
776 ensure_type_or_null(k);
777
778 // Since I just called 'Value' to compute the set of run-time values
779 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
780 // cache Value. Later requests for the local phase->type of this Node can
781 // use the cached Value instead of suffering with 'bottom_type'.
782 const Type *t = k->Value(this); // Get runtime Value set
783 assert(t != NULL, "value sanity");
784 if (type_or_null(k) != t) {
785 #ifndef PRODUCT
786 // Do not count initial visit to node as a transformation
787 if (type_or_null(k) == NULL) {
788 inc_new_values();
789 set_progress();
790 }
791 #endif
792 set_type(k, t);
793 // If k is a TypeNode, capture any more-precise type permanently into Node
794 k->raise_bottom_type(t);
795 }
796
797 if( t->singleton() && !k->is_Con() ) {
798 NOT_PRODUCT( set_progress(); )
799 return makecon(t); // Turn into a constant
800 }
801
802 // Now check for Identities
803 Node *i = k->Identity(this); // Look for a nearby replacement
804 if( i != k ) { // Found? Return replacement!
805 NOT_PRODUCT( set_progress(); )
806 return i;
807 }
808
809 // Global Value Numbering
810 i = hash_find_insert(k); // Insert if new
811 if( i && (i != k) ) {
812 // Return the pre-existing node
813 NOT_PRODUCT( set_progress(); )
814 return i;
815 }
816
817 // Return Idealized original
818 return k;
819 }
820
821 #ifdef ASSERT
822 //------------------------------dead_loop_check--------------------------------
823 // Check for a simple dead loop when a data node references itself directly
824 // or through an other data node excluding cons and phis.
825 void PhaseGVN::dead_loop_check( Node *n ) {
826 // Phi may reference itself in a loop
827 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
828 // Do 2 levels check and only data inputs.
829 bool no_dead_loop = true;
830 uint cnt = n->req();
831 for (uint i = 1; i < cnt && no_dead_loop; i++) {
832 Node *in = n->in(i);
833 if (in == n) {
834 no_dead_loop = false;
835 } else if (in != NULL && !in->is_dead_loop_safe()) {
836 uint icnt = in->req();
837 for (uint j = 1; j < icnt && no_dead_loop; j++) {
838 if (in->in(j) == n || in->in(j) == in)
839 no_dead_loop = false;
840 }
841 }
842 }
843 if (!no_dead_loop) n->dump(3);
844 assert(no_dead_loop, "dead loop detected");
845 }
846 }
847 #endif
848
849 //=============================================================================
850 //------------------------------PhaseIterGVN-----------------------------------
851 // Initialize hash table to fresh and clean for +VerifyOpto
852 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ),
853 _stack(C->live_nodes() >> 1),
854 _delay_transform(false) {
855 }
856
857 //------------------------------PhaseIterGVN-----------------------------------
858 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
859 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
860 _worklist( igvn->_worklist ),
861 _stack( igvn->_stack ),
862 _delay_transform(igvn->_delay_transform)
863 {
864 }
865
866 //------------------------------PhaseIterGVN-----------------------------------
867 // Initialize with previous PhaseGVN info from Parser
868 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
869 _worklist(*C->for_igvn()),
870 // TODO: Before incremental inlining it was allocated only once and it was fine. Now that
871 // the constructor is used in incremental inlining, this consumes too much memory:
872 // _stack(C->live_nodes() >> 1),
873 // So, as a band-aid, we replace this by:
874 _stack(C->comp_arena(), 32),
875 _delay_transform(false)
876 {
877 uint max;
878
879 // Dead nodes in the hash table inherited from GVN were not treated as
880 // roots during def-use info creation; hence they represent an invisible
881 // use. Clear them out.
882 max = _table.size();
883 for( uint i = 0; i < max; ++i ) {
884 Node *n = _table.at(i);
885 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
886 if( n->is_top() ) continue;
887 assert( false, "Parse::remove_useless_nodes missed this node");
888 hash_delete(n);
889 }
890 }
891
892 // Any Phis or Regions on the worklist probably had uses that could not
893 // make more progress because the uses were made while the Phis and Regions
894 // were in half-built states. Put all uses of Phis and Regions on worklist.
895 max = _worklist.size();
896 for( uint j = 0; j < max; j++ ) {
897 Node *n = _worklist.at(j);
898 uint uop = n->Opcode();
899 if( uop == Op_Phi || uop == Op_Region ||
900 n->is_Type() ||
901 n->is_Mem() )
902 add_users_to_worklist(n);
903 }
904 }
905
906
907 #ifndef PRODUCT
908 void PhaseIterGVN::verify_step(Node* n) {
909 _verify_window[_verify_counter % _verify_window_size] = n;
910 ++_verify_counter;
911 ResourceMark rm;
912 ResourceArea *area = Thread::current()->resource_area();
913 VectorSet old_space(area), new_space(area);
914 if (C->unique() < 1000 ||
915 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
916 ++_verify_full_passes;
917 Node::verify_recur(C->root(), -1, old_space, new_space);
918 }
919 const int verify_depth = 4;
920 for ( int i = 0; i < _verify_window_size; i++ ) {
921 Node* n = _verify_window[i];
922 if ( n == NULL ) continue;
923 if( n->in(0) == NodeSentinel ) { // xform_idom
924 _verify_window[i] = n->in(1);
925 --i; continue;
926 }
927 // Typical fanout is 1-2, so this call visits about 6 nodes.
928 Node::verify_recur(n, verify_depth, old_space, new_space);
929 }
930 }
931 #endif
932
933
934 //------------------------------init_worklist----------------------------------
935 // Initialize worklist for each node.
936 void PhaseIterGVN::init_worklist( Node *n ) {
937 if( _worklist.member(n) ) return;
938 _worklist.push(n);
939 uint cnt = n->req();
940 for( uint i =0 ; i < cnt; i++ ) {
941 Node *m = n->in(i);
942 if( m ) init_worklist(m);
943 }
944 }
945
946 //------------------------------optimize---------------------------------------
947 void PhaseIterGVN::optimize() {
948 debug_only(uint num_processed = 0;);
949 #ifndef PRODUCT
950 {
951 _verify_counter = 0;
952 _verify_full_passes = 0;
953 for ( int i = 0; i < _verify_window_size; i++ ) {
954 _verify_window[i] = NULL;
955 }
956 }
957 #endif
958
959 #ifdef ASSERT
960 Node* prev = NULL;
961 uint rep_cnt = 0;
962 #endif
963 uint loop_count = 0;
964
965 // Pull from worklist; transform node;
966 // If node has changed: update edge info and put uses on worklist.
967 while( _worklist.size() ) {
968 if (C->check_node_count(NodeLimitFudgeFactor * 2,
969 "out of nodes optimizing method")) {
970 return;
971 }
972 Node *n = _worklist.pop();
973 if (++loop_count >= K * C->live_nodes()) {
974 debug_only(n->dump(4);)
975 assert(false, "infinite loop in PhaseIterGVN::optimize");
976 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
977 return;
978 }
979 #ifdef ASSERT
980 if (n == prev) {
981 if (++rep_cnt > 3) {
982 n->dump(4);
983 assert(false, "loop in Ideal transformation");
984 }
985 } else {
986 rep_cnt = 0;
987 }
988 prev = n;
989 #endif
990 if (TraceIterativeGVN && Verbose) {
991 tty->print(" Pop ");
992 NOT_PRODUCT( n->dump(); )
993 debug_only(if( (num_processed++ % 100) == 0 ) _worklist.print_set();)
994 }
995
996 if (n->outcnt() != 0) {
997
998 #ifndef PRODUCT
999 uint wlsize = _worklist.size();
1000 const Type* oldtype = type_or_null(n);
1001 #endif //PRODUCT
1002
1003 Node *nn = transform_old(n);
1004
1005 #ifndef PRODUCT
1006 if (TraceIterativeGVN) {
1007 const Type* newtype = type_or_null(n);
1008 if (nn != n) {
1009 // print old node
1010 tty->print("< ");
1011 if (oldtype != newtype && oldtype != NULL) {
1012 oldtype->dump();
1013 }
1014 do { tty->print("\t"); } while (tty->position() < 16);
1015 tty->print("<");
1016 n->dump();
1017 }
1018 if (oldtype != newtype || nn != n) {
1019 // print new node and/or new type
1020 if (oldtype == NULL) {
1021 tty->print("* ");
1022 } else if (nn != n) {
1023 tty->print("> ");
1024 } else {
1025 tty->print("= ");
1026 }
1027 if (newtype == NULL) {
1028 tty->print("null");
1029 } else {
1030 newtype->dump();
1031 }
1032 do { tty->print("\t"); } while (tty->position() < 16);
1033 nn->dump();
1034 }
1035 if (Verbose && wlsize < _worklist.size()) {
1036 tty->print(" Push {");
1037 while (wlsize != _worklist.size()) {
1038 Node* pushed = _worklist.at(wlsize++);
1039 tty->print(" %d", pushed->_idx);
1040 }
1041 tty->print_cr(" }");
1042 }
1043 }
1044 if( VerifyIterativeGVN && nn != n ) {
1045 verify_step((Node*) NULL); // ignore n, it might be subsumed
1046 }
1047 #endif
1048 } else if (!n->is_top()) {
1049 remove_dead_node(n);
1050 }
1051 }
1052
1053 #ifndef PRODUCT
1054 C->verify_graph_edges();
1055 if( VerifyOpto && allow_progress() ) {
1056 // Must turn off allow_progress to enable assert and break recursion
1057 C->root()->verify();
1058 { // Check if any progress was missed using IterGVN
1059 // Def-Use info enables transformations not attempted in wash-pass
1060 // e.g. Region/Phi cleanup, ...
1061 // Null-check elision -- may not have reached fixpoint
1062 // do not propagate to dominated nodes
1063 ResourceMark rm;
1064 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
1065 // Fill worklist completely
1066 igvn2.init_worklist(C->root());
1067
1068 igvn2.set_allow_progress(false);
1069 igvn2.optimize();
1070 igvn2.set_allow_progress(true);
1071 }
1072 }
1073 if ( VerifyIterativeGVN && PrintOpto ) {
1074 if ( _verify_counter == _verify_full_passes )
1075 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
1076 (int) _verify_full_passes);
1077 else
1078 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
1079 (int) _verify_counter, (int) _verify_full_passes);
1080 }
1081 #endif
1082 }
1083
1084
1085 //------------------register_new_node_with_optimizer---------------------------
1086 // Register a new node with the optimizer. Update the types array, the def-use
1087 // info. Put on worklist.
1088 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
1089 set_type_bottom(n);
1090 _worklist.push(n);
1091 if (orig != NULL) C->copy_node_notes_to(n, orig);
1092 return n;
1093 }
1094
1095 //------------------------------transform--------------------------------------
1096 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
1097 Node *PhaseIterGVN::transform( Node *n ) {
1098 if (_delay_transform) {
1099 // Register the node but don't optimize for now
1100 register_new_node_with_optimizer(n);
1101 return n;
1102 }
1103
1104 // If brand new node, make space in type array, and give it a type.
1105 ensure_type_or_null(n);
1106 if (type_or_null(n) == NULL) {
1107 set_type_bottom(n);
1108 }
1109
1110 return transform_old(n);
1111 }
1112
1113 //------------------------------transform_old----------------------------------
1114 Node *PhaseIterGVN::transform_old( Node *n ) {
1115 #ifndef PRODUCT
1116 debug_only(uint loop_count = 0;);
1117 set_transforms();
1118 #endif
1119 // Remove 'n' from hash table in case it gets modified
1120 _table.hash_delete(n);
1121 if( VerifyIterativeGVN ) {
1122 assert( !_table.find_index(n->_idx), "found duplicate entry in table");
1123 }
1124
1125 // Apply the Ideal call in a loop until it no longer applies
1126 Node *k = n;
1127 DEBUG_ONLY(dead_loop_check(k);)
1128 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1129 Node *i = k->Ideal(this, /*can_reshape=*/true);
1130 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1131 #ifndef PRODUCT
1132 if( VerifyIterativeGVN )
1133 verify_step(k);
1134 if( i && VerifyOpto ) {
1135 if( !allow_progress() ) {
1136 if (i->is_Add() && i->outcnt() == 1) {
1137 // Switched input to left side because this is the only use
1138 } else if( i->is_If() && (i->in(0) == NULL) ) {
1139 // This IF is dead because it is dominated by an equivalent IF When
1140 // dominating if changed, info is not propagated sparsely to 'this'
1141 // Propagating this info further will spuriously identify other
1142 // progress.
1143 return i;
1144 } else
1145 set_progress();
1146 } else
1147 set_progress();
1148 }
1149 #endif
1150
1151 while( i ) {
1152 #ifndef PRODUCT
1153 debug_only( if( loop_count >= K ) i->dump(4); )
1154 assert(loop_count < K, "infinite loop in PhaseIterGVN::transform");
1155 debug_only( loop_count++; )
1156 #endif
1157 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1158 // Made a change; put users of original Node on worklist
1159 add_users_to_worklist( k );
1160 // Replacing root of transform tree?
1161 if( k != i ) {
1162 // Make users of old Node now use new.
1163 subsume_node( k, i );
1164 k = i;
1165 }
1166 DEBUG_ONLY(dead_loop_check(k);)
1167 // Try idealizing again
1168 DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1169 i = k->Ideal(this, /*can_reshape=*/true);
1170 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1171 #ifndef PRODUCT
1172 if( VerifyIterativeGVN )
1173 verify_step(k);
1174 if( i && VerifyOpto ) set_progress();
1175 #endif
1176 }
1177
1178 // If brand new node, make space in type array.
1179 ensure_type_or_null(k);
1180
1181 // See what kind of values 'k' takes on at runtime
1182 const Type *t = k->Value(this);
1183 assert(t != NULL, "value sanity");
1184
1185 // Since I just called 'Value' to compute the set of run-time values
1186 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1187 // cache Value. Later requests for the local phase->type of this Node can
1188 // use the cached Value instead of suffering with 'bottom_type'.
1189 if (t != type_or_null(k)) {
1190 NOT_PRODUCT( set_progress(); )
1191 NOT_PRODUCT( inc_new_values();)
1192 set_type(k, t);
1193 // If k is a TypeNode, capture any more-precise type permanently into Node
1194 k->raise_bottom_type(t);
1195 // Move users of node to worklist
1196 add_users_to_worklist( k );
1197 }
1198
1199 // If 'k' computes a constant, replace it with a constant
1200 if( t->singleton() && !k->is_Con() ) {
1201 NOT_PRODUCT( set_progress(); )
1202 Node *con = makecon(t); // Make a constant
1203 add_users_to_worklist( k );
1204 subsume_node( k, con ); // Everybody using k now uses con
1205 return con;
1206 }
1207
1208 // Now check for Identities
1209 i = k->Identity(this); // Look for a nearby replacement
1210 if( i != k ) { // Found? Return replacement!
1211 NOT_PRODUCT( set_progress(); )
1212 add_users_to_worklist( k );
1213 subsume_node( k, i ); // Everybody using k now uses i
1214 return i;
1215 }
1216
1217 // Global Value Numbering
1218 i = hash_find_insert(k); // Check for pre-existing node
1219 if( i && (i != k) ) {
1220 // Return the pre-existing node if it isn't dead
1221 NOT_PRODUCT( set_progress(); )
1222 add_users_to_worklist( k );
1223 subsume_node( k, i ); // Everybody using k now uses i
1224 return i;
1225 }
1226
1227 // Return Idealized original
1228 return k;
1229 }
1230
1231 //---------------------------------saturate------------------------------------
1232 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1233 const Type* limit_type) const {
1234 return new_type->narrow(old_type);
1235 }
1236
1237 //------------------------------remove_globally_dead_node----------------------
1238 // Kill a globally dead Node. All uses are also globally dead and are
1239 // aggressively trimmed.
1240 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1241 enum DeleteProgress {
1242 PROCESS_INPUTS,
1243 PROCESS_OUTPUTS
1244 };
1245 assert(_stack.is_empty(), "not empty");
1246 _stack.push(dead, PROCESS_INPUTS);
1247
1248 while (_stack.is_nonempty()) {
1249 dead = _stack.node();
1250 if (dead->Opcode() == Op_SafePoint) {
1251 dead->as_SafePoint()->disconnect_from_root(this);
1252 }
1253 uint progress_state = _stack.index();
1254 assert(dead != C->root(), "killing root, eh?");
1255 assert(!dead->is_top(), "add check for top when pushing");
1256 NOT_PRODUCT( set_progress(); )
1257 if (progress_state == PROCESS_INPUTS) {
1258 // After following inputs, continue to outputs
1259 _stack.set_index(PROCESS_OUTPUTS);
1260 if (!dead->is_Con()) { // Don't kill cons but uses
1261 bool recurse = false;
1262 // Remove from hash table
1263 _table.hash_delete( dead );
1264 // Smash all inputs to 'dead', isolating him completely
1265 for (uint i = 0; i < dead->req(); i++) {
1266 Node *in = dead->in(i);
1267 if (in != NULL && in != C->top()) { // Points to something?
1268 int nrep = dead->replace_edge(in, NULL); // Kill edges
1269 assert((nrep > 0), "sanity");
1270 if (in->outcnt() == 0) { // Made input go dead?
1271 _stack.push(in, PROCESS_INPUTS); // Recursively remove
1272 recurse = true;
1273 } else if (in->outcnt() == 1 &&
1274 in->has_special_unique_user()) {
1275 _worklist.push(in->unique_out());
1276 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1277 if (in->Opcode() == Op_Region) {
1278 _worklist.push(in);
1279 } else if (in->is_Store()) {
1280 DUIterator_Fast imax, i = in->fast_outs(imax);
1281 _worklist.push(in->fast_out(i));
1282 i++;
1283 if (in->outcnt() == 2) {
1284 _worklist.push(in->fast_out(i));
1285 i++;
1286 }
1287 assert(!(i < imax), "sanity");
1288 }
1289 } else if (in->Opcode() == Op_AddP && CallLeafNode::has_only_g1_wb_pre_uses(in)) {
1290 add_users_to_worklist(in);
1291 }
1292 if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory &&
1293 in->is_Proj() && in->in(0) != NULL && in->in(0)->is_Initialize()) {
1294 // A Load that directly follows an InitializeNode is
1295 // going away. The Stores that follow are candidates
1296 // again to be captured by the InitializeNode.
1297 for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) {
1298 Node *n = in->fast_out(j);
1299 if (n->is_Store()) {
1300 _worklist.push(n);
1301 }
1302 }
1303 }
1304 } // if (in != NULL && in != C->top())
1305 } // for (uint i = 0; i < dead->req(); i++)
1306 if (recurse) {
1307 continue;
1308 }
1309 } // if (!dead->is_Con())
1310 } // if (progress_state == PROCESS_INPUTS)
1311
1312 // Aggressively kill globally dead uses
1313 // (Rather than pushing all the outs at once, we push one at a time,
1314 // plus the parent to resume later, because of the indefinite number
1315 // of edge deletions per loop trip.)
1316 if (dead->outcnt() > 0) {
1317 // Recursively remove output edges
1318 _stack.push(dead->raw_out(0), PROCESS_INPUTS);
1319 } else {
1320 // Finished disconnecting all input and output edges.
1321 _stack.pop();
1322 // Remove dead node from iterative worklist
1323 _worklist.remove(dead);
1324 // Constant node that has no out-edges and has only one in-edge from
1325 // root is usually dead. However, sometimes reshaping walk makes
1326 // it reachable by adding use edges. So, we will NOT count Con nodes
1327 // as dead to be conservative about the dead node count at any
1328 // given time.
1329 if (!dead->is_Con()) {
1330 C->record_dead_node(dead->_idx);
1331 }
1332 if (dead->is_macro()) {
1333 C->remove_macro_node(dead);
1334 }
1335 if (dead->is_expensive()) {
1336 C->remove_expensive_node(dead);
1337 }
1338 if (dead->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
1339 C->remove_shenandoah_barrier(reinterpret_cast<ShenandoahLoadReferenceBarrierNode*>(dead));
1340 }
1341 CastIINode* cast = dead->isa_CastII();
1342 if (cast != NULL && cast->has_range_check()) {
1343 C->remove_range_check_cast(cast);
1344 }
1345 }
1346 } // while (_stack.is_nonempty())
1347 }
1348
1349 //------------------------------subsume_node-----------------------------------
1350 // Remove users from node 'old' and add them to node 'nn'.
1351 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1352 if (old->Opcode() == Op_SafePoint) {
1353 old->as_SafePoint()->disconnect_from_root(this);
1354 }
1355 assert( old != hash_find(old), "should already been removed" );
1356 assert( old != C->top(), "cannot subsume top node");
1357 // Copy debug or profile information to the new version:
1358 C->copy_node_notes_to(nn, old);
1359 // Move users of node 'old' to node 'nn'
1360 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1361 Node* use = old->last_out(i); // for each use...
1362 // use might need re-hashing (but it won't if it's a new node)
1363 bool is_in_table = _table.hash_delete( use );
1364 // Update use-def info as well
1365 // We remove all occurrences of old within use->in,
1366 // so as to avoid rehashing any node more than once.
1367 // The hash table probe swamps any outer loop overhead.
1368 uint num_edges = 0;
1369 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1370 if (use->in(j) == old) {
1371 use->set_req(j, nn);
1372 ++num_edges;
1373 }
1374 }
1375 // Insert into GVN hash table if unique
1376 // If a duplicate, 'use' will be cleaned up when pulled off worklist
1377 if( is_in_table ) {
1378 hash_find_insert(use);
1379 }
1380 i -= num_edges; // we deleted 1 or more copies of this edge
1381 }
1382
1383 // Search for instance field data PhiNodes in the same region pointing to the old
1384 // memory PhiNode and update their instance memory ids to point to the new node.
1385 if (old->is_Phi() && old->as_Phi()->type()->has_memory() && old->in(0) != NULL) {
1386 Node* region = old->in(0);
1387 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1388 PhiNode* phi = region->fast_out(i)->isa_Phi();
1389 if (phi != NULL && phi->inst_mem_id() == (int)old->_idx) {
1390 phi->set_inst_mem_id((int)nn->_idx);
1391 }
1392 }
1393 }
1394
1395 // Smash all inputs to 'old', isolating him completely
1396 Node *temp = new (C) Node(1);
1397 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1398 remove_dead_node( old );
1399 temp->del_req(0); // Yank bogus edge
1400 #ifndef PRODUCT
1401 if( VerifyIterativeGVN ) {
1402 for ( int i = 0; i < _verify_window_size; i++ ) {
1403 if ( _verify_window[i] == old )
1404 _verify_window[i] = nn;
1405 }
1406 }
1407 #endif
1408 _worklist.remove(temp); // this can be necessary
1409 temp->destruct(); // reuse the _idx of this little guy
1410 }
1411
1412 //------------------------------add_users_to_worklist--------------------------
1413 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1414 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1415 _worklist.push(n->fast_out(i)); // Push on worklist
1416 }
1417 }
1418
1419 // Return counted loop Phi if as a counted loop exit condition, cmp
1420 // compares the the induction variable with n
1421 static PhiNode* countedloop_phi_from_cmp(CmpINode* cmp, Node* n) {
1422 for (DUIterator_Fast imax, i = cmp->fast_outs(imax); i < imax; i++) {
1423 Node* bol = cmp->fast_out(i);
1424 for (DUIterator_Fast i2max, i2 = bol->fast_outs(i2max); i2 < i2max; i2++) {
1425 Node* iff = bol->fast_out(i2);
1426 if (iff->is_CountedLoopEnd()) {
1427 CountedLoopEndNode* cle = iff->as_CountedLoopEnd();
1428 if (cle->limit() == n) {
1429 PhiNode* phi = cle->phi();
1430 if (phi != NULL) {
1431 return phi;
1432 }
1433 }
1434 }
1435 }
1436 }
1437 return NULL;
1438 }
1439
1440 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1441 add_users_to_worklist0(n);
1442
1443 // Move users of node to worklist
1444 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1445 Node* use = n->fast_out(i); // Get use
1446
1447 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1448 use->is_Store() ) // Enable store/load same address
1449 add_users_to_worklist0(use);
1450
1451 // If we changed the receiver type to a call, we need to revisit
1452 // the Catch following the call. It's looking for a non-NULL
1453 // receiver to know when to enable the regular fall-through path
1454 // in addition to the NullPtrException path.
1455 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1456 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control);
1457 if (p != NULL) {
1458 add_users_to_worklist0(p);
1459 }
1460 }
1461
1462 uint use_op = use->Opcode();
1463 if(use->is_Cmp()) { // Enable CMP/BOOL optimization
1464 add_users_to_worklist(use); // Put Bool on worklist
1465 if (use->outcnt() > 0) {
1466 Node* bol = use->raw_out(0);
1467 if (bol->outcnt() > 0) {
1468 Node* iff = bol->raw_out(0);
1469 if (iff->outcnt() == 2) {
1470 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1471 // phi merging either 0 or 1 onto the worklist
1472 Node* ifproj0 = iff->raw_out(0);
1473 Node* ifproj1 = iff->raw_out(1);
1474 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1475 Node* region0 = ifproj0->raw_out(0);
1476 Node* region1 = ifproj1->raw_out(0);
1477 if( region0 == region1 )
1478 add_users_to_worklist0(region0);
1479 }
1480 }
1481 }
1482 }
1483 if (use_op == Op_CmpI) {
1484 Node* phi = countedloop_phi_from_cmp((CmpINode*)use, n);
1485 if (phi != NULL) {
1486 // If an opaque node feeds into the limit condition of a
1487 // CountedLoop, we need to process the Phi node for the
1488 // induction variable when the opaque node is removed:
1489 // the range of values taken by the Phi is now known and
1490 // so its type is also known.
1491 _worklist.push(phi);
1492 }
1493 Node* in1 = use->in(1);
1494 for (uint i = 0; i < in1->outcnt(); i++) {
1495 if (in1->raw_out(i)->Opcode() == Op_CastII) {
1496 Node* castii = in1->raw_out(i);
1497 if (castii->in(0) != NULL && castii->in(0)->in(0) != NULL && castii->in(0)->in(0)->is_If()) {
1498 Node* ifnode = castii->in(0)->in(0);
1499 if (ifnode->in(1) != NULL && ifnode->in(1)->is_Bool() && ifnode->in(1)->in(1) == use) {
1500 // Reprocess a CastII node that may depend on an
1501 // opaque node value when the opaque node is
1502 // removed. In case it carries a dependency we can do
1503 // a better job of computing its type.
1504 _worklist.push(castii);
1505 }
1506 }
1507 }
1508 }
1509 }
1510 }
1511
1512 // If changed Cast input, check Phi users for simple cycles
1513 if( use->is_ConstraintCast() || use->is_CheckCastPP() ) {
1514 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1515 Node* u = use->fast_out(i2);
1516 if (u->is_Phi())
1517 _worklist.push(u);
1518 }
1519 }
1520 // If changed LShift inputs, check RShift users for useless sign-ext
1521 if( use_op == Op_LShiftI ) {
1522 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1523 Node* u = use->fast_out(i2);
1524 if (u->Opcode() == Op_RShiftI)
1525 _worklist.push(u);
1526 }
1527 }
1528 // If changed AddI/SubI inputs, check CmpU for range check optimization.
1529 if (use_op == Op_AddI || use_op == Op_SubI) {
1530 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1531 Node* u = use->fast_out(i2);
1532 if (u->is_Cmp() && (u->Opcode() == Op_CmpU)) {
1533 _worklist.push(u);
1534 }
1535 }
1536 }
1537 // If changed AddP inputs, check Stores for loop invariant
1538 if( use_op == Op_AddP ) {
1539 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1540 Node* u = use->fast_out(i2);
1541 if (u->is_Mem())
1542 _worklist.push(u);
1543 }
1544 }
1545 // If changed initialization activity, check dependent Stores
1546 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1547 InitializeNode* init = use->as_Allocate()->initialization();
1548 if (init != NULL) {
1549 Node* imem = init->proj_out(TypeFunc::Memory);
1550 if (imem != NULL) add_users_to_worklist0(imem);
1551 }
1552 }
1553 if (use_op == Op_Initialize) {
1554 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory);
1555 if (imem != NULL) add_users_to_worklist0(imem);
1556 }
1557
1558 if (use->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
1559 Node* cmp = use->find_out_with(Op_CmpP);
1560 if (cmp != NULL) {
1561 _worklist.push(cmp);
1562 }
1563 }
1564 }
1565 }
1566
1567 /**
1568 * Remove the speculative part of all types that we know of
1569 */
1570 void PhaseIterGVN::remove_speculative_types() {
1571 assert(UseTypeSpeculation, "speculation is off");
1572 for (uint i = 0; i < _types.Size(); i++) {
1573 const Type* t = _types.fast_lookup(i);
1574 if (t != NULL) {
1575 _types.map(i, t->remove_speculative());
1576 }
1577 }
1578 _table.check_no_speculative_types();
1579 }
1580
1581 //=============================================================================
1582 #ifndef PRODUCT
1583 uint PhaseCCP::_total_invokes = 0;
1584 uint PhaseCCP::_total_constants = 0;
1585 #endif
1586 //------------------------------PhaseCCP---------------------------------------
1587 // Conditional Constant Propagation, ala Wegman & Zadeck
1588 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1589 NOT_PRODUCT( clear_constants(); )
1590 assert( _worklist.size() == 0, "" );
1591 // Clear out _nodes from IterGVN. Must be clear to transform call.
1592 _nodes.clear(); // Clear out from IterGVN
1593 analyze();
1594 }
1595
1596 #ifndef PRODUCT
1597 //------------------------------~PhaseCCP--------------------------------------
1598 PhaseCCP::~PhaseCCP() {
1599 inc_invokes();
1600 _total_constants += count_constants();
1601 }
1602 #endif
1603
1604
1605 #ifdef ASSERT
1606 static bool ccp_type_widens(const Type* t, const Type* t0) {
1607 assert(t->meet(t0) == t, "Not monotonic");
1608 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1609 case Type::Int:
1610 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1611 break;
1612 case Type::Long:
1613 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1614 break;
1615 }
1616 return true;
1617 }
1618 #endif //ASSERT
1619
1620 //------------------------------analyze----------------------------------------
1621 void PhaseCCP::analyze() {
1622 // Initialize all types to TOP, optimistic analysis
1623 for (int i = C->unique() - 1; i >= 0; i--) {
1624 _types.map(i,Type::TOP);
1625 }
1626
1627 // Push root onto worklist
1628 Unique_Node_List worklist;
1629 worklist.push(C->root());
1630
1631 // Pull from worklist; compute new value; push changes out.
1632 // This loop is the meat of CCP.
1633 while( worklist.size() ) {
1634 Node *n = worklist.pop();
1635 const Type *t = n->Value(this);
1636 if (t != type(n)) {
1637 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1638 #ifndef PRODUCT
1639 if( TracePhaseCCP ) {
1640 t->dump();
1641 do { tty->print("\t"); } while (tty->position() < 16);
1642 n->dump();
1643 }
1644 #endif
1645 set_type(n, t);
1646 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1647 Node* m = n->fast_out(i); // Get user
1648 if (m->is_Region()) { // New path to Region? Must recheck Phis too
1649 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1650 Node* p = m->fast_out(i2); // Propagate changes to uses
1651 if (p->bottom_type() != type(p)) { // If not already bottomed out
1652 worklist.push(p); // Propagate change to user
1653 }
1654 }
1655 }
1656 // If we changed the receiver type to a call, we need to revisit
1657 // the Catch following the call. It's looking for a non-NULL
1658 // receiver to know when to enable the regular fall-through path
1659 // in addition to the NullPtrException path
1660 if (m->is_Call()) {
1661 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1662 Node* p = m->fast_out(i2); // Propagate changes to uses
1663 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control) {
1664 Node* catch_node = p->find_out_with(Op_Catch);
1665 if (catch_node != NULL) {
1666 worklist.push(catch_node);
1667 }
1668 }
1669 }
1670 }
1671 if (m->bottom_type() != type(m)) { // If not already bottomed out
1672 worklist.push(m); // Propagate change to user
1673 }
1674
1675 // CmpU nodes can get their type information from two nodes up in the
1676 // graph (instead of from the nodes immediately above). Make sure they
1677 // are added to the worklist if nodes they depend on are updated, since
1678 // they could be missed and get wrong types otherwise.
1679 uint m_op = m->Opcode();
1680 if (m_op == Op_AddI || m_op == Op_SubI) {
1681 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1682 Node* p = m->fast_out(i2); // Propagate changes to uses
1683 if (p->Opcode() == Op_CmpU) {
1684 // Got a CmpU which might need the new type information from node n.
1685 if(p->bottom_type() != type(p)) { // If not already bottomed out
1686 worklist.push(p); // Propagate change to user
1687 }
1688 }
1689 }
1690 }
1691 if (m->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
1692 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1693 Node* p = m->fast_out(i2);
1694 if (p->Opcode() == Op_CmpP) {
1695 if(p->bottom_type() != type(p)) {
1696 worklist.push(p);
1697 }
1698 } else if (p->Opcode() == Op_AddP) {
1699 for (DUIterator_Fast i3max, i3 = p->fast_outs(i3max); i3 < i3max; i3++) {
1700 Node* q = p->fast_out(i3);
1701 if (q->is_Load()) {
1702 if(q->bottom_type() != type(q)) {
1703 worklist.push(q);
1704 }
1705 }
1706 }
1707 }
1708 }
1709 }
1710 // If n is used in a counted loop exit condition then the type
1711 // of the counted loop's Phi depends on the type of n. See
1712 // PhiNode::Value().
1713 if (m_op == Op_CmpI) {
1714 PhiNode* phi = countedloop_phi_from_cmp((CmpINode*)m, n);
1715 if (phi != NULL) {
1716 worklist.push(phi);
1717 }
1718 }
1719 }
1720 }
1721 }
1722 }
1723
1724 //------------------------------do_transform-----------------------------------
1725 // Top level driver for the recursive transformer
1726 void PhaseCCP::do_transform() {
1727 // Correct leaves of new-space Nodes; they point to old-space.
1728 C->set_root( transform(C->root())->as_Root() );
1729 assert( C->top(), "missing TOP node" );
1730 assert( C->root(), "missing root" );
1731 }
1732
1733 //------------------------------transform--------------------------------------
1734 // Given a Node in old-space, clone him into new-space.
1735 // Convert any of his old-space children into new-space children.
1736 Node *PhaseCCP::transform( Node *n ) {
1737 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1738 if( new_node != NULL )
1739 return new_node; // Been there, done that, return old answer
1740 new_node = transform_once(n); // Check for constant
1741 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1742
1743 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1744 GrowableArray <Node *> trstack(C->live_nodes() >> 1);
1745
1746 trstack.push(new_node); // Process children of cloned node
1747 while ( trstack.is_nonempty() ) {
1748 Node *clone = trstack.pop();
1749 uint cnt = clone->req();
1750 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1751 Node *input = clone->in(i);
1752 if( input != NULL ) { // Ignore NULLs
1753 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1754 if( new_input == NULL ) {
1755 new_input = transform_once(input); // Check for constant
1756 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1757 trstack.push(new_input);
1758 }
1759 assert( new_input == clone->in(i), "insanity check");
1760 }
1761 }
1762 }
1763 return new_node;
1764 }
1765
1766
1767 //------------------------------transform_once---------------------------------
1768 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1769 Node *PhaseCCP::transform_once( Node *n ) {
1770 const Type *t = type(n);
1771 // Constant? Use constant Node instead
1772 if( t->singleton() ) {
1773 Node *nn = n; // Default is to return the original constant
1774 if( t == Type::TOP ) {
1775 // cache my top node on the Compile instance
1776 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1777 C->set_cached_top_node( ConNode::make(C, Type::TOP) );
1778 set_type(C->top(), Type::TOP);
1779 }
1780 nn = C->top();
1781 }
1782 if( !n->is_Con() ) {
1783 if( t != Type::TOP ) {
1784 nn = makecon(t); // ConNode::make(t);
1785 NOT_PRODUCT( inc_constants(); )
1786 } else if( n->is_Region() ) { // Unreachable region
1787 // Note: nn == C->top()
1788 n->set_req(0, NULL); // Cut selfreference
1789 // Eagerly remove dead phis to avoid phis copies creation.
1790 for (DUIterator i = n->outs(); n->has_out(i); i++) {
1791 Node* m = n->out(i);
1792 if( m->is_Phi() ) {
1793 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1794 replace_node(m, nn);
1795 --i; // deleted this phi; rescan starting with next position
1796 }
1797 }
1798 }
1799 replace_node(n,nn); // Update DefUse edges for new constant
1800 }
1801 return nn;
1802 }
1803
1804 // If x is a TypeNode, capture any more-precise type permanently into Node
1805 if (t != n->bottom_type()) {
1806 hash_delete(n); // changing bottom type may force a rehash
1807 n->raise_bottom_type(t);
1808 _worklist.push(n); // n re-enters the hash table via the worklist
1809 }
1810
1811 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1812 switch( n->Opcode() ) {
1813 case Op_FastLock: // Revisit FastLocks for lock coarsening
1814 case Op_If:
1815 case Op_CountedLoopEnd:
1816 case Op_Region:
1817 case Op_Loop:
1818 case Op_CountedLoop:
1819 case Op_Conv2B:
1820 case Op_Opaque1:
1821 case Op_Opaque2:
1822 _worklist.push(n);
1823 break;
1824 default:
1825 break;
1826 }
1827
1828 return n;
1829 }
1830
1831 //---------------------------------saturate------------------------------------
1832 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
1833 const Type* limit_type) const {
1834 const Type* wide_type = new_type->widen(old_type, limit_type);
1835 if (wide_type != new_type) { // did we widen?
1836 // If so, we may have widened beyond the limit type. Clip it back down.
1837 new_type = wide_type->filter(limit_type);
1838 }
1839 return new_type;
1840 }
1841
1842 //------------------------------print_statistics-------------------------------
1843 #ifndef PRODUCT
1844 void PhaseCCP::print_statistics() {
1845 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
1846 }
1847 #endif
1848
1849
1850 //=============================================================================
1851 #ifndef PRODUCT
1852 uint PhasePeephole::_total_peepholes = 0;
1853 #endif
1854 //------------------------------PhasePeephole----------------------------------
1855 // Conditional Constant Propagation, ala Wegman & Zadeck
1856 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
1857 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
1858 NOT_PRODUCT( clear_peepholes(); )
1859 }
1860
1861 #ifndef PRODUCT
1862 //------------------------------~PhasePeephole---------------------------------
1863 PhasePeephole::~PhasePeephole() {
1864 _total_peepholes += count_peepholes();
1865 }
1866 #endif
1867
1868 //------------------------------transform--------------------------------------
1869 Node *PhasePeephole::transform( Node *n ) {
1870 ShouldNotCallThis();
1871 return NULL;
1872 }
1873
1874 //------------------------------do_transform-----------------------------------
1875 void PhasePeephole::do_transform() {
1876 bool method_name_not_printed = true;
1877
1878 // Examine each basic block
1879 for (uint block_number = 1; block_number < _cfg.number_of_blocks(); ++block_number) {
1880 Block* block = _cfg.get_block(block_number);
1881 bool block_not_printed = true;
1882
1883 // and each instruction within a block
1884 uint end_index = block->number_of_nodes();
1885 // block->end_idx() not valid after PhaseRegAlloc
1886 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
1887 Node *n = block->get_node(instruction_index);
1888 if( n->is_Mach() ) {
1889 MachNode *m = n->as_Mach();
1890 int deleted_count = 0;
1891 // check for peephole opportunities
1892 MachNode *m2 = m->peephole( block, instruction_index, _regalloc, deleted_count, C );
1893 if( m2 != NULL ) {
1894 #ifndef PRODUCT
1895 if( PrintOptoPeephole ) {
1896 // Print method, first time only
1897 if( C->method() && method_name_not_printed ) {
1898 C->method()->print_short_name(); tty->cr();
1899 method_name_not_printed = false;
1900 }
1901 // Print this block
1902 if( Verbose && block_not_printed) {
1903 tty->print_cr("in block");
1904 block->dump();
1905 block_not_printed = false;
1906 }
1907 // Print instructions being deleted
1908 for( int i = (deleted_count - 1); i >= 0; --i ) {
1909 block->get_node(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
1910 }
1911 tty->print_cr("replaced with");
1912 // Print new instruction
1913 m2->format(_regalloc);
1914 tty->print("\n\n");
1915 }
1916 #endif
1917 // Remove old nodes from basic block and update instruction_index
1918 // (old nodes still exist and may have edges pointing to them
1919 // as register allocation info is stored in the allocator using
1920 // the node index to live range mappings.)
1921 uint safe_instruction_index = (instruction_index - deleted_count);
1922 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
1923 block->remove_node( instruction_index );
1924 }
1925 // install new node after safe_instruction_index
1926 block->insert_node(m2, safe_instruction_index + 1);
1927 end_index = block->number_of_nodes() - 1; // Recompute new block size
1928 NOT_PRODUCT( inc_peepholes(); )
1929 }
1930 }
1931 }
1932 }
1933 }
1934
1935 //------------------------------print_statistics-------------------------------
1936 #ifndef PRODUCT
1937 void PhasePeephole::print_statistics() {
1938 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
1939 }
1940 #endif
1941
1942
1943 //=============================================================================
1944 //------------------------------set_req_X--------------------------------------
1945 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
1946 assert( is_not_dead(n), "can not use dead node");
1947 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
1948 Node *old = in(i);
1949 set_req(i, n);
1950
1951 // old goes dead?
1952 if( old ) {
1953 switch (old->outcnt()) {
1954 case 0:
1955 // Put into the worklist to kill later. We do not kill it now because the
1956 // recursive kill will delete the current node (this) if dead-loop exists
1957 if (!old->is_top())
1958 igvn->_worklist.push( old );
1959 break;
1960 case 1:
1961 if( old->is_Store() || old->has_special_unique_user() )
1962 igvn->add_users_to_worklist( old );
1963 break;
1964 case 2:
1965 if( old->is_Store() )
1966 igvn->add_users_to_worklist( old );
1967 if( old->Opcode() == Op_Region )
1968 igvn->_worklist.push(old);
1969 break;
1970 case 3:
1971 if( old->Opcode() == Op_Region ) {
1972 igvn->_worklist.push(old);
1973 igvn->add_users_to_worklist( old );
1974 }
1975 break;
1976 default:
1977 break;
1978 }
1979 if (old->Opcode() == Op_AddP && CallLeafNode::has_only_g1_wb_pre_uses(old)) {
1980 igvn->add_users_to_worklist(old);
1981 }
1982 }
1983
1984 }
1985
1986 //-------------------------------replace_by-----------------------------------
1987 // Using def-use info, replace one node for another. Follow the def-use info
1988 // to all users of the OLD node. Then make all uses point to the NEW node.
1989 void Node::replace_by(Node *new_node) {
1990 assert(!is_top(), "top node has no DU info");
1991 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
1992 Node* use = last_out(i);
1993 uint uses_found = 0;
1994 for (uint j = 0; j < use->len(); j++) {
1995 if (use->in(j) == this) {
1996 if (j < use->req())
1997 use->set_req(j, new_node);
1998 else use->set_prec(j, new_node);
1999 uses_found++;
2000 }
2001 }
2002 i -= uses_found; // we deleted 1 or more copies of this edge
2003 }
2004 }
2005
2006 //=============================================================================
2007 //-----------------------------------------------------------------------------
2008 void Type_Array::grow( uint i ) {
2009 if( !_max ) {
2010 _max = 1;
2011 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
2012 _types[0] = NULL;
2013 }
2014 uint old = _max;
2015 while( i >= _max ) _max <<= 1; // Double to fit
2016 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
2017 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
2018 }
2019
2020 //------------------------------dump-------------------------------------------
2021 #ifndef PRODUCT
2022 void Type_Array::dump() const {
2023 uint max = Size();
2024 for( uint i = 0; i < max; i++ ) {
2025 if( _types[i] != NULL ) {
2026 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
2027 }
2028 }
2029 }
2030 #endif