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comparison src/share/vm/opto/phaseX.cpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 1997-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 #include "incls/_precompiled.incl"
26 #include "incls/_phaseX.cpp.incl"
27
28 //=============================================================================
29 #define NODE_HASH_MINIMUM_SIZE 255
30 //------------------------------NodeHash---------------------------------------
31 NodeHash::NodeHash(uint est_max_size) :
32 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
33 _a(Thread::current()->resource_area()),
34 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), // (Node**)_a->Amalloc(_max * sizeof(Node*)) ),
35 _inserts(0), _insert_limit( insert_limit() ),
36 _look_probes(0), _lookup_hits(0), _lookup_misses(0),
37 _total_insert_probes(0), _total_inserts(0),
38 _insert_probes(0), _grows(0) {
39 // _sentinel must be in the current node space
40 _sentinel = new (Compile::current(), 1) ProjNode(NULL, TypeFunc::Control);
41 memset(_table,0,sizeof(Node*)*_max);
42 }
43
44 //------------------------------NodeHash---------------------------------------
45 NodeHash::NodeHash(Arena *arena, uint est_max_size) :
46 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
47 _a(arena),
48 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ),
49 _inserts(0), _insert_limit( insert_limit() ),
50 _look_probes(0), _lookup_hits(0), _lookup_misses(0),
51 _delete_probes(0), _delete_hits(0), _delete_misses(0),
52 _total_insert_probes(0), _total_inserts(0),
53 _insert_probes(0), _grows(0) {
54 // _sentinel must be in the current node space
55 _sentinel = new (Compile::current(), 1) ProjNode(NULL, TypeFunc::Control);
56 memset(_table,0,sizeof(Node*)*_max);
57 }
58
59 //------------------------------NodeHash---------------------------------------
60 NodeHash::NodeHash(NodeHash *nh) {
61 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
62 // just copy in all the fields
63 *this = *nh;
64 // nh->_sentinel must be in the current node space
65 }
66
67 //------------------------------hash_find--------------------------------------
68 // Find in hash table
69 Node *NodeHash::hash_find( const Node *n ) {
70 // ((Node*)n)->set_hash( n->hash() );
71 uint hash = n->hash();
72 if (hash == Node::NO_HASH) {
73 debug_only( _lookup_misses++ );
74 return NULL;
75 }
76 uint key = hash & (_max-1);
77 uint stride = key | 0x01;
78 debug_only( _look_probes++ );
79 Node *k = _table[key]; // Get hashed value
80 if( !k ) { // ?Miss?
81 debug_only( _lookup_misses++ );
82 return NULL; // Miss!
83 }
84
85 int op = n->Opcode();
86 uint req = n->req();
87 while( 1 ) { // While probing hash table
88 if( k->req() == req && // Same count of inputs
89 k->Opcode() == op ) { // Same Opcode
90 for( uint i=0; i<req; i++ )
91 if( n->in(i)!=k->in(i)) // Different inputs?
92 goto collision; // "goto" is a speed hack...
93 if( n->cmp(*k) ) { // Check for any special bits
94 debug_only( _lookup_hits++ );
95 return k; // Hit!
96 }
97 }
98 collision:
99 debug_only( _look_probes++ );
100 key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime
101 k = _table[key]; // Get hashed value
102 if( !k ) { // ?Miss?
103 debug_only( _lookup_misses++ );
104 return NULL; // Miss!
105 }
106 }
107 ShouldNotReachHere();
108 return NULL;
109 }
110
111 //------------------------------hash_find_insert-------------------------------
112 // Find in hash table, insert if not already present
113 // Used to preserve unique entries in hash table
114 Node *NodeHash::hash_find_insert( Node *n ) {
115 // n->set_hash( );
116 uint hash = n->hash();
117 if (hash == Node::NO_HASH) {
118 debug_only( _lookup_misses++ );
119 return NULL;
120 }
121 uint key = hash & (_max-1);
122 uint stride = key | 0x01; // stride must be relatively prime to table siz
123 uint first_sentinel = 0; // replace a sentinel if seen.
124 debug_only( _look_probes++ );
125 Node *k = _table[key]; // Get hashed value
126 if( !k ) { // ?Miss?
127 debug_only( _lookup_misses++ );
128 _table[key] = n; // Insert into table!
129 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
130 check_grow(); // Grow table if insert hit limit
131 return NULL; // Miss!
132 }
133 else if( k == _sentinel ) {
134 first_sentinel = key; // Can insert here
135 }
136
137 int op = n->Opcode();
138 uint req = n->req();
139 while( 1 ) { // While probing hash table
140 if( k->req() == req && // Same count of inputs
141 k->Opcode() == op ) { // Same Opcode
142 for( uint i=0; i<req; i++ )
143 if( n->in(i)!=k->in(i)) // Different inputs?
144 goto collision; // "goto" is a speed hack...
145 if( n->cmp(*k) ) { // Check for any special bits
146 debug_only( _lookup_hits++ );
147 return k; // Hit!
148 }
149 }
150 collision:
151 debug_only( _look_probes++ );
152 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
153 k = _table[key]; // Get hashed value
154 if( !k ) { // ?Miss?
155 debug_only( _lookup_misses++ );
156 key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel?
157 _table[key] = n; // Insert into table!
158 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
159 check_grow(); // Grow table if insert hit limit
160 return NULL; // Miss!
161 }
162 else if( first_sentinel == 0 && k == _sentinel ) {
163 first_sentinel = key; // Can insert here
164 }
165
166 }
167 ShouldNotReachHere();
168 return NULL;
169 }
170
171 //------------------------------hash_insert------------------------------------
172 // Insert into hash table
173 void NodeHash::hash_insert( Node *n ) {
174 // // "conflict" comments -- print nodes that conflict
175 // bool conflict = false;
176 // n->set_hash();
177 uint hash = n->hash();
178 if (hash == Node::NO_HASH) {
179 return;
180 }
181 check_grow();
182 uint key = hash & (_max-1);
183 uint stride = key | 0x01;
184
185 while( 1 ) { // While probing hash table
186 debug_only( _insert_probes++ );
187 Node *k = _table[key]; // Get hashed value
188 if( !k || (k == _sentinel) ) break; // Found a slot
189 assert( k != n, "already inserted" );
190 // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print(" conflict: "); k->dump(); conflict = true; }
191 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
192 }
193 _table[key] = n; // Insert into table!
194 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
195 // if( conflict ) { n->dump(); }
196 }
197
198 //------------------------------hash_delete------------------------------------
199 // Replace in hash table with sentinal
200 bool NodeHash::hash_delete( const Node *n ) {
201 Node *k;
202 uint hash = n->hash();
203 if (hash == Node::NO_HASH) {
204 debug_only( _delete_misses++ );
205 return false;
206 }
207 uint key = hash & (_max-1);
208 uint stride = key | 0x01;
209 debug_only( uint counter = 0; );
210 for( ; /* (k != NULL) && (k != _sentinal) */; ) {
211 debug_only( counter++ );
212 debug_only( _delete_probes++ );
213 k = _table[key]; // Get hashed value
214 if( !k ) { // Miss?
215 debug_only( _delete_misses++ );
216 #ifdef ASSERT
217 if( VerifyOpto ) {
218 for( uint i=0; i < _max; i++ )
219 assert( _table[i] != n, "changed edges with rehashing" );
220 }
221 #endif
222 return false; // Miss! Not in chain
223 }
224 else if( n == k ) {
225 debug_only( _delete_hits++ );
226 _table[key] = _sentinel; // Hit! Label as deleted entry
227 debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table.
228 return true;
229 }
230 else {
231 // collision: move through table with prime offset
232 key = (key + stride/*7*/) & (_max-1);
233 assert( counter <= _insert_limit, "Cycle in hash-table");
234 }
235 }
236 ShouldNotReachHere();
237 return false;
238 }
239
240 //------------------------------round_up---------------------------------------
241 // Round up to nearest power of 2
242 uint NodeHash::round_up( uint x ) {
243 x += (x>>2); // Add 25% slop
244 if( x <16 ) return 16; // Small stuff
245 uint i=16;
246 while( i < x ) i <<= 1; // Double to fit
247 return i; // Return hash table size
248 }
249
250 //------------------------------grow-------------------------------------------
251 // Grow _table to next power of 2 and insert old entries
252 void NodeHash::grow() {
253 // Record old state
254 uint old_max = _max;
255 Node **old_table = _table;
256 // Construct new table with twice the space
257 _grows++;
258 _total_inserts += _inserts;
259 _total_insert_probes += _insert_probes;
260 _inserts = 0;
261 _insert_probes = 0;
262 _max = _max << 1;
263 _table = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) );
264 memset(_table,0,sizeof(Node*)*_max);
265 _insert_limit = insert_limit();
266 // Insert old entries into the new table
267 for( uint i = 0; i < old_max; i++ ) {
268 Node *m = *old_table++;
269 if( !m || m == _sentinel ) continue;
270 debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table.
271 hash_insert(m);
272 }
273 }
274
275 //------------------------------clear------------------------------------------
276 // Clear all entries in _table to NULL but keep storage
277 void NodeHash::clear() {
278 #ifdef ASSERT
279 // Unlock all nodes upon removal from table.
280 for (uint i = 0; i < _max; i++) {
281 Node* n = _table[i];
282 if (!n || n == _sentinel) continue;
283 n->exit_hash_lock();
284 }
285 #endif
286
287 memset( _table, 0, _max * sizeof(Node*) );
288 }
289
290 //-----------------------remove_useless_nodes----------------------------------
291 // Remove useless nodes from value table,
292 // implementation does not depend on hash function
293 void NodeHash::remove_useless_nodes(VectorSet &useful) {
294
295 // Dead nodes in the hash table inherited from GVN should not replace
296 // existing nodes, remove dead nodes.
297 uint max = size();
298 Node *sentinel_node = sentinel();
299 for( uint i = 0; i < max; ++i ) {
300 Node *n = at(i);
301 if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) {
302 debug_only(n->exit_hash_lock()); // Unlock the node when removed
303 _table[i] = sentinel_node; // Replace with placeholder
304 }
305 }
306 }
307
308 #ifndef PRODUCT
309 //------------------------------dump-------------------------------------------
310 // Dump statistics for the hash table
311 void NodeHash::dump() {
312 _total_inserts += _inserts;
313 _total_insert_probes += _insert_probes;
314 if( PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0) ) { // PrintOptoGVN
315 if( PrintCompilation2 ) {
316 for( uint i=0; i<_max; i++ )
317 if( _table[i] )
318 tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx);
319 }
320 tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max);
321 tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0);
322 tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses));
323 tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts);
324 // sentinels increase lookup cost, but not insert cost
325 assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function");
326 assert( _inserts+(_inserts>>3) < _max, "table too full" );
327 assert( _inserts*3+100 >= _insert_probes, "bad hash function" );
328 }
329 }
330
331 Node *NodeHash::find_index(uint idx) { // For debugging
332 // Find an entry by its index value
333 for( uint i = 0; i < _max; i++ ) {
334 Node *m = _table[i];
335 if( !m || m == _sentinel ) continue;
336 if( m->_idx == (uint)idx ) return m;
337 }
338 return NULL;
339 }
340 #endif
341
342 #ifdef ASSERT
343 NodeHash::~NodeHash() {
344 // Unlock all nodes upon destruction of table.
345 if (_table != (Node**)badAddress) clear();
346 }
347
348 void NodeHash::operator=(const NodeHash& nh) {
349 // Unlock all nodes upon replacement of table.
350 if (&nh == this) return;
351 if (_table != (Node**)badAddress) clear();
352 memcpy(this, &nh, sizeof(*this));
353 // Do not increment hash_lock counts again.
354 // Instead, be sure we never again use the source table.
355 ((NodeHash*)&nh)->_table = (Node**)badAddress;
356 }
357
358
359 #endif
360
361
362 //=============================================================================
363 //------------------------------PhaseRemoveUseless-----------------------------
364 // 1) Use a breadthfirst walk to collect useful nodes reachable from root.
365 PhaseRemoveUseless::PhaseRemoveUseless( PhaseGVN *gvn, Unique_Node_List *worklist ) : Phase(Remove_Useless),
366 _useful(Thread::current()->resource_area()) {
367
368 // Implementation requires 'UseLoopSafepoints == true' and an edge from root
369 // to each SafePointNode at a backward branch. Inserted in add_safepoint().
370 if( !UseLoopSafepoints || !OptoRemoveUseless ) return;
371
372 // Identify nodes that are reachable from below, useful.
373 C->identify_useful_nodes(_useful);
374
375 // Remove all useless nodes from PhaseValues' recorded types
376 // Must be done before disconnecting nodes to preserve hash-table-invariant
377 gvn->remove_useless_nodes(_useful.member_set());
378
379 // Remove all useless nodes from future worklist
380 worklist->remove_useless_nodes(_useful.member_set());
381
382 // Disconnect 'useless' nodes that are adjacent to useful nodes
383 C->remove_useless_nodes(_useful);
384
385 // Remove edges from "root" to each SafePoint at a backward branch.
386 // They were inserted during parsing (see add_safepoint()) to make infinite
387 // loops without calls or exceptions visible to root, i.e., useful.
388 Node *root = C->root();
389 if( root != NULL ) {
390 for( uint i = root->req(); i < root->len(); ++i ) {
391 Node *n = root->in(i);
392 if( n != NULL && n->is_SafePoint() ) {
393 root->rm_prec(i);
394 --i;
395 }
396 }
397 }
398 }
399
400
401 //=============================================================================
402 //------------------------------PhaseTransform---------------------------------
403 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
404 _arena(Thread::current()->resource_area()),
405 _nodes(_arena),
406 _types(_arena)
407 {
408 init_con_caches();
409 #ifndef PRODUCT
410 clear_progress();
411 clear_transforms();
412 set_allow_progress(true);
413 #endif
414 // Force allocation for currently existing nodes
415 _types.map(C->unique(), NULL);
416 }
417
418 //------------------------------PhaseTransform---------------------------------
419 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
420 _arena(arena),
421 _nodes(arena),
422 _types(arena)
423 {
424 init_con_caches();
425 #ifndef PRODUCT
426 clear_progress();
427 clear_transforms();
428 set_allow_progress(true);
429 #endif
430 // Force allocation for currently existing nodes
431 _types.map(C->unique(), NULL);
432 }
433
434 //------------------------------PhaseTransform---------------------------------
435 // Initialize with previously generated type information
436 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
437 _arena(pt->_arena),
438 _nodes(pt->_nodes),
439 _types(pt->_types)
440 {
441 init_con_caches();
442 #ifndef PRODUCT
443 clear_progress();
444 clear_transforms();
445 set_allow_progress(true);
446 #endif
447 }
448
449 void PhaseTransform::init_con_caches() {
450 memset(_icons,0,sizeof(_icons));
451 memset(_lcons,0,sizeof(_lcons));
452 memset(_zcons,0,sizeof(_zcons));
453 }
454
455
456 //--------------------------------find_int_type--------------------------------
457 const TypeInt* PhaseTransform::find_int_type(Node* n) {
458 if (n == NULL) return NULL;
459 // Call type_or_null(n) to determine node's type since we might be in
460 // parse phase and call n->Value() may return wrong type.
461 // (For example, a phi node at the beginning of loop parsing is not ready.)
462 const Type* t = type_or_null(n);
463 if (t == NULL) return NULL;
464 return t->isa_int();
465 }
466
467
468 //-------------------------------find_long_type--------------------------------
469 const TypeLong* PhaseTransform::find_long_type(Node* n) {
470 if (n == NULL) return NULL;
471 // (See comment above on type_or_null.)
472 const Type* t = type_or_null(n);
473 if (t == NULL) return NULL;
474 return t->isa_long();
475 }
476
477
478 #ifndef PRODUCT
479 void PhaseTransform::dump_old2new_map() const {
480 _nodes.dump();
481 }
482
483 void PhaseTransform::dump_new( uint nidx ) const {
484 for( uint i=0; i<_nodes.Size(); i++ )
485 if( _nodes[i] && _nodes[i]->_idx == nidx ) {
486 _nodes[i]->dump();
487 tty->cr();
488 tty->print_cr("Old index= %d",i);
489 return;
490 }
491 tty->print_cr("Node %d not found in the new indices", nidx);
492 }
493
494 //------------------------------dump_types-------------------------------------
495 void PhaseTransform::dump_types( ) const {
496 _types.dump();
497 }
498
499 //------------------------------dump_nodes_and_types---------------------------
500 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
501 VectorSet visited(Thread::current()->resource_area());
502 dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
503 }
504
505 //------------------------------dump_nodes_and_types_recur---------------------
506 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
507 if( !n ) return;
508 if( depth == 0 ) return;
509 if( visited.test_set(n->_idx) ) return;
510 for( uint i=0; i<n->len(); i++ ) {
511 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
512 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
513 }
514 n->dump();
515 if (type_or_null(n) != NULL) {
516 tty->print(" "); type(n)->dump(); tty->cr();
517 }
518 }
519
520 #endif
521
522
523 //=============================================================================
524 //------------------------------PhaseValues------------------------------------
525 // Set minimum table size to "255"
526 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
527 NOT_PRODUCT( clear_new_values(); )
528 }
529
530 //------------------------------PhaseValues------------------------------------
531 // Set minimum table size to "255"
532 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
533 _table(&ptv->_table) {
534 NOT_PRODUCT( clear_new_values(); )
535 }
536
537 //------------------------------PhaseValues------------------------------------
538 // Used by +VerifyOpto. Clear out hash table but copy _types array.
539 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
540 _table(ptv->arena(),ptv->_table.size()) {
541 NOT_PRODUCT( clear_new_values(); )
542 }
543
544 //------------------------------~PhaseValues-----------------------------------
545 #ifndef PRODUCT
546 PhaseValues::~PhaseValues() {
547 _table.dump();
548
549 // Statistics for value progress and efficiency
550 if( PrintCompilation && Verbose && WizardMode ) {
551 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
552 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values());
553 if( made_transforms() != 0 ) {
554 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() );
555 } else {
556 tty->cr();
557 }
558 }
559 }
560 #endif
561
562 //------------------------------makecon----------------------------------------
563 ConNode* PhaseTransform::makecon(const Type *t) {
564 assert(t->singleton(), "must be a constant");
565 assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
566 switch (t->base()) { // fast paths
567 case Type::Half:
568 case Type::Top: return (ConNode*) C->top();
569 case Type::Int: return intcon( t->is_int()->get_con() );
570 case Type::Long: return longcon( t->is_long()->get_con() );
571 }
572 if (t->is_zero_type())
573 return zerocon(t->basic_type());
574 return uncached_makecon(t);
575 }
576
577 //--------------------------uncached_makecon-----------------------------------
578 // Make an idealized constant - one of ConINode, ConPNode, etc.
579 ConNode* PhaseValues::uncached_makecon(const Type *t) {
580 assert(t->singleton(), "must be a constant");
581 ConNode* x = ConNode::make(C, t);
582 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
583 if (k == NULL) {
584 set_type(x, t); // Missed, provide type mapping
585 GrowableArray<Node_Notes*>* nna = C->node_note_array();
586 if (nna != NULL) {
587 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
588 loc->clear(); // do not put debug info on constants
589 }
590 // Collect points-to information for escape analysys
591 ConnectionGraph *cgr = C->congraph();
592 if (cgr != NULL) {
593 cgr->record_escape(x, this);
594 }
595 } else {
596 x->destruct(); // Hit, destroy duplicate constant
597 x = k; // use existing constant
598 }
599 return x;
600 }
601
602 //------------------------------intcon-----------------------------------------
603 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
604 ConINode* PhaseTransform::intcon(int i) {
605 // Small integer? Check cache! Check that cached node is not dead
606 if (i >= _icon_min && i <= _icon_max) {
607 ConINode* icon = _icons[i-_icon_min];
608 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
609 return icon;
610 }
611 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
612 assert(icon->is_Con(), "");
613 if (i >= _icon_min && i <= _icon_max)
614 _icons[i-_icon_min] = icon; // Cache small integers
615 return icon;
616 }
617
618 //------------------------------longcon----------------------------------------
619 // Fast long constant.
620 ConLNode* PhaseTransform::longcon(jlong l) {
621 // Small integer? Check cache! Check that cached node is not dead
622 if (l >= _lcon_min && l <= _lcon_max) {
623 ConLNode* lcon = _lcons[l-_lcon_min];
624 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
625 return lcon;
626 }
627 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
628 assert(lcon->is_Con(), "");
629 if (l >= _lcon_min && l <= _lcon_max)
630 _lcons[l-_lcon_min] = lcon; // Cache small integers
631 return lcon;
632 }
633
634 //------------------------------zerocon-----------------------------------------
635 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
636 ConNode* PhaseTransform::zerocon(BasicType bt) {
637 assert((uint)bt <= _zcon_max, "domain check");
638 ConNode* zcon = _zcons[bt];
639 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
640 return zcon;
641 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
642 _zcons[bt] = zcon;
643 return zcon;
644 }
645
646
647
648 //=============================================================================
649 //------------------------------transform--------------------------------------
650 // Return a node which computes the same function as this node, but in a
651 // faster or cheaper fashion. The Node passed in here must have no other
652 // pointers to it, as its storage will be reclaimed if the Node can be
653 // optimized away.
654 Node *PhaseGVN::transform( Node *n ) {
655 NOT_PRODUCT( set_transforms(); )
656
657 // Apply the Ideal call in a loop until it no longer applies
658 Node *k = n;
659 NOT_PRODUCT( uint loop_count = 0; )
660 while( 1 ) {
661 Node *i = k->Ideal(this, /*can_reshape=*/false);
662 if( !i ) break;
663 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
664 // Can never reclaim storage for Ideal calls, because the Ideal call
665 // returns a new Node, bumping the High Water Mark and our old Node
666 // is caught behind the new one.
667 //if( k != i ) {
668 //k->destruct(); // Reclaim storage for recent node
669 k = i;
670 //}
671 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
672 }
673 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
674
675 // If brand new node, make space in type array.
676 ensure_type_or_null(k);
677
678 // Cache result of Value call since it can be expensive
679 // (abstract interpretation of node 'k' using phase->_types[ inputs ])
680 const Type *t = k->Value(this); // Get runtime Value set
681 assert(t != NULL, "value sanity");
682 if (type_or_null(k) != t) {
683 #ifndef PRODUCT
684 // Do not record transformation or value construction on first visit
685 if (type_or_null(k) == NULL) {
686 inc_new_values();
687 set_progress();
688 }
689 #endif
690 set_type(k, t);
691 // If k is a TypeNode, capture any more-precise type permanently into Node
692 k->raise_bottom_type(t);
693 }
694
695 if( t->singleton() && !k->is_Con() ) {
696 //k->destruct(); // Reclaim storage for recent node
697 NOT_PRODUCT( set_progress(); )
698 return makecon(t); // Turn into a constant
699 }
700
701 // Now check for Identities
702 Node *i = k->Identity(this); // Look for a nearby replacement
703 if( i != k ) { // Found? Return replacement!
704 //k->destruct(); // Reclaim storage for recent node
705 NOT_PRODUCT( set_progress(); )
706 return i;
707 }
708
709 // Try Global Value Numbering
710 i = hash_find_insert(k); // Found older value when i != NULL
711 if( i && i != k ) { // Hit? Return the old guy
712 NOT_PRODUCT( set_progress(); )
713 return i;
714 }
715
716 // Collect points-to information for escape analysys
717 ConnectionGraph *cgr = C->congraph();
718 if (cgr != NULL) {
719 cgr->record_escape(k, this);
720 }
721
722 // Return Idealized original
723 return k;
724 }
725
726 //------------------------------transform--------------------------------------
727 // Return a node which computes the same function as this node, but
728 // in a faster or cheaper fashion.
729 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
730 NOT_PRODUCT( set_transforms(); )
731
732 // Apply the Ideal call in a loop until it no longer applies
733 Node *k = n;
734 NOT_PRODUCT( uint loop_count = 0; )
735 while( 1 ) {
736 Node *i = k->Ideal(this, /*can_reshape=*/false);
737 if( !i ) break;
738 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
739 k = i;
740 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
741 }
742 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
743
744
745 // If brand new node, make space in type array.
746 ensure_type_or_null(k);
747
748 // Since I just called 'Value' to compute the set of run-time values
749 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
750 // cache Value. Later requests for the local phase->type of this Node can
751 // use the cached Value instead of suffering with 'bottom_type'.
752 const Type *t = k->Value(this); // Get runtime Value set
753 assert(t != NULL, "value sanity");
754 if (type_or_null(k) != t) {
755 #ifndef PRODUCT
756 // Do not count initial visit to node as a transformation
757 if (type_or_null(k) == NULL) {
758 inc_new_values();
759 set_progress();
760 }
761 #endif
762 set_type(k, t);
763 // If k is a TypeNode, capture any more-precise type permanently into Node
764 k->raise_bottom_type(t);
765 }
766
767 if( t->singleton() && !k->is_Con() ) {
768 NOT_PRODUCT( set_progress(); )
769 return makecon(t); // Turn into a constant
770 }
771
772 // Now check for Identities
773 Node *i = k->Identity(this); // Look for a nearby replacement
774 if( i != k ) { // Found? Return replacement!
775 NOT_PRODUCT( set_progress(); )
776 return i;
777 }
778
779 // Global Value Numbering
780 i = hash_find_insert(k); // Insert if new
781 if( i && (i != k) ) {
782 // Return the pre-existing node
783 NOT_PRODUCT( set_progress(); )
784 return i;
785 }
786
787 // Return Idealized original
788 return k;
789 }
790
791 #ifdef ASSERT
792 //------------------------------dead_loop_check--------------------------------
793 // Check for a simple dead loop when a data node references itself direcly
794 // or through an other data node excluding cons and phis.
795 void PhaseGVN::dead_loop_check( Node *n ) {
796 // Phi may reference itself in a loop
797 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
798 // Do 2 levels check and only data inputs.
799 bool no_dead_loop = true;
800 uint cnt = n->req();
801 for (uint i = 1; i < cnt && no_dead_loop; i++) {
802 Node *in = n->in(i);
803 if (in == n) {
804 no_dead_loop = false;
805 } else if (in != NULL && !in->is_dead_loop_safe()) {
806 uint icnt = in->req();
807 for (uint j = 1; j < icnt && no_dead_loop; j++) {
808 if (in->in(j) == n || in->in(j) == in)
809 no_dead_loop = false;
810 }
811 }
812 }
813 if (!no_dead_loop) n->dump(3);
814 assert(no_dead_loop, "dead loop detected");
815 }
816 }
817 #endif
818
819 //=============================================================================
820 //------------------------------PhaseIterGVN-----------------------------------
821 // Initialize hash table to fresh and clean for +VerifyOpto
822 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ) {
823 }
824
825 //------------------------------PhaseIterGVN-----------------------------------
826 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
827 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
828 _worklist( igvn->_worklist )
829 {
830 }
831
832 //------------------------------PhaseIterGVN-----------------------------------
833 // Initialize with previous PhaseGVN info from Parser
834 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
835 _worklist(*C->for_igvn())
836 {
837 uint max;
838
839 // Dead nodes in the hash table inherited from GVN were not treated as
840 // roots during def-use info creation; hence they represent an invisible
841 // use. Clear them out.
842 max = _table.size();
843 for( uint i = 0; i < max; ++i ) {
844 Node *n = _table.at(i);
845 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
846 if( n->is_top() ) continue;
847 assert( false, "Parse::remove_useless_nodes missed this node");
848 hash_delete(n);
849 }
850 }
851
852 // Any Phis or Regions on the worklist probably had uses that could not
853 // make more progress because the uses were made while the Phis and Regions
854 // were in half-built states. Put all uses of Phis and Regions on worklist.
855 max = _worklist.size();
856 for( uint j = 0; j < max; j++ ) {
857 Node *n = _worklist.at(j);
858 uint uop = n->Opcode();
859 if( uop == Op_Phi || uop == Op_Region ||
860 n->is_Type() ||
861 n->is_Mem() )
862 add_users_to_worklist(n);
863 }
864 }
865
866
867 #ifndef PRODUCT
868 void PhaseIterGVN::verify_step(Node* n) {
869 _verify_window[_verify_counter % _verify_window_size] = n;
870 ++_verify_counter;
871 ResourceMark rm;
872 ResourceArea *area = Thread::current()->resource_area();
873 VectorSet old_space(area), new_space(area);
874 if (C->unique() < 1000 ||
875 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
876 ++_verify_full_passes;
877 Node::verify_recur(C->root(), -1, old_space, new_space);
878 }
879 const int verify_depth = 4;
880 for ( int i = 0; i < _verify_window_size; i++ ) {
881 Node* n = _verify_window[i];
882 if ( n == NULL ) continue;
883 if( n->in(0) == NodeSentinel ) { // xform_idom
884 _verify_window[i] = n->in(1);
885 --i; continue;
886 }
887 // Typical fanout is 1-2, so this call visits about 6 nodes.
888 Node::verify_recur(n, verify_depth, old_space, new_space);
889 }
890 }
891 #endif
892
893
894 //------------------------------init_worklist----------------------------------
895 // Initialize worklist for each node.
896 void PhaseIterGVN::init_worklist( Node *n ) {
897 if( _worklist.member(n) ) return;
898 _worklist.push(n);
899 uint cnt = n->req();
900 for( uint i =0 ; i < cnt; i++ ) {
901 Node *m = n->in(i);
902 if( m ) init_worklist(m);
903 }
904 }
905
906 //------------------------------optimize---------------------------------------
907 void PhaseIterGVN::optimize() {
908 debug_only(uint num_processed = 0;);
909 #ifndef PRODUCT
910 {
911 _verify_counter = 0;
912 _verify_full_passes = 0;
913 for ( int i = 0; i < _verify_window_size; i++ ) {
914 _verify_window[i] = NULL;
915 }
916 }
917 #endif
918
919 // Pull from worklist; transform node;
920 // If node has changed: update edge info and put uses on worklist.
921 while( _worklist.size() ) {
922 Node *n = _worklist.pop();
923 if (TraceIterativeGVN && Verbose) {
924 tty->print(" Pop ");
925 NOT_PRODUCT( n->dump(); )
926 debug_only(if( (num_processed++ % 100) == 0 ) _worklist.print_set();)
927 }
928
929 if (n->outcnt() != 0) {
930
931 #ifndef PRODUCT
932 uint wlsize = _worklist.size();
933 const Type* oldtype = type_or_null(n);
934 #endif //PRODUCT
935
936 Node *nn = transform_old(n);
937
938 #ifndef PRODUCT
939 if (TraceIterativeGVN) {
940 const Type* newtype = type_or_null(n);
941 if (nn != n) {
942 // print old node
943 tty->print("< ");
944 if (oldtype != newtype && oldtype != NULL) {
945 oldtype->dump();
946 }
947 do { tty->print("\t"); } while (tty->position() < 16);
948 tty->print("<");
949 n->dump();
950 }
951 if (oldtype != newtype || nn != n) {
952 // print new node and/or new type
953 if (oldtype == NULL) {
954 tty->print("* ");
955 } else if (nn != n) {
956 tty->print("> ");
957 } else {
958 tty->print("= ");
959 }
960 if (newtype == NULL) {
961 tty->print("null");
962 } else {
963 newtype->dump();
964 }
965 do { tty->print("\t"); } while (tty->position() < 16);
966 nn->dump();
967 }
968 if (Verbose && wlsize < _worklist.size()) {
969 tty->print(" Push {");
970 while (wlsize != _worklist.size()) {
971 Node* pushed = _worklist.at(wlsize++);
972 tty->print(" %d", pushed->_idx);
973 }
974 tty->print_cr(" }");
975 }
976 }
977 if( VerifyIterativeGVN && nn != n ) {
978 verify_step((Node*) NULL); // ignore n, it might be subsumed
979 }
980 #endif
981 } else if (!n->is_top()) {
982 remove_dead_node(n);
983 }
984 }
985
986 #ifndef PRODUCT
987 C->verify_graph_edges();
988 if( VerifyOpto && allow_progress() ) {
989 // Must turn off allow_progress to enable assert and break recursion
990 C->root()->verify();
991 { // Check if any progress was missed using IterGVN
992 // Def-Use info enables transformations not attempted in wash-pass
993 // e.g. Region/Phi cleanup, ...
994 // Null-check elision -- may not have reached fixpoint
995 // do not propagate to dominated nodes
996 ResourceMark rm;
997 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
998 // Fill worklist completely
999 igvn2.init_worklist(C->root());
1000
1001 igvn2.set_allow_progress(false);
1002 igvn2.optimize();
1003 igvn2.set_allow_progress(true);
1004 }
1005 }
1006 if ( VerifyIterativeGVN && PrintOpto ) {
1007 if ( _verify_counter == _verify_full_passes )
1008 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
1009 _verify_full_passes);
1010 else
1011 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
1012 _verify_counter, _verify_full_passes);
1013 }
1014 #endif
1015 }
1016
1017
1018 //------------------register_new_node_with_optimizer---------------------------
1019 // Register a new node with the optimizer. Update the types array, the def-use
1020 // info. Put on worklist.
1021 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
1022 set_type_bottom(n);
1023 _worklist.push(n);
1024 if (orig != NULL) C->copy_node_notes_to(n, orig);
1025 return n;
1026 }
1027
1028 //------------------------------transform--------------------------------------
1029 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
1030 Node *PhaseIterGVN::transform( Node *n ) {
1031 // If brand new node, make space in type array, and give it a type.
1032 ensure_type_or_null(n);
1033 if (type_or_null(n) == NULL) {
1034 set_type_bottom(n);
1035 }
1036
1037 return transform_old(n);
1038 }
1039
1040 //------------------------------transform_old----------------------------------
1041 Node *PhaseIterGVN::transform_old( Node *n ) {
1042 #ifndef PRODUCT
1043 debug_only(uint loop_count = 0;);
1044 set_transforms();
1045 #endif
1046 // Remove 'n' from hash table in case it gets modified
1047 _table.hash_delete(n);
1048 if( VerifyIterativeGVN ) {
1049 assert( !_table.find_index(n->_idx), "found duplicate entry in table");
1050 }
1051
1052 // Apply the Ideal call in a loop until it no longer applies
1053 Node *k = n;
1054 DEBUG_ONLY(dead_loop_check(k);)
1055 Node *i = k->Ideal(this, /*can_reshape=*/true);
1056 #ifndef PRODUCT
1057 if( VerifyIterativeGVN )
1058 verify_step(k);
1059 if( i && VerifyOpto ) {
1060 if( !allow_progress() ) {
1061 if (i->is_Add() && i->outcnt() == 1) {
1062 // Switched input to left side because this is the only use
1063 } else if( i->is_If() && (i->in(0) == NULL) ) {
1064 // This IF is dead because it is dominated by an equivalent IF When
1065 // dominating if changed, info is not propagated sparsely to 'this'
1066 // Propagating this info further will spuriously identify other
1067 // progress.
1068 return i;
1069 } else
1070 set_progress();
1071 } else
1072 set_progress();
1073 }
1074 #endif
1075
1076 while( i ) {
1077 #ifndef PRODUCT
1078 debug_only( if( loop_count >= K ) i->dump(4); )
1079 assert(loop_count < K, "infinite loop in PhaseIterGVN::transform");
1080 debug_only( loop_count++; )
1081 #endif
1082 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1083 // Made a change; put users of original Node on worklist
1084 add_users_to_worklist( k );
1085 // Replacing root of transform tree?
1086 if( k != i ) {
1087 // Make users of old Node now use new.
1088 subsume_node( k, i );
1089 k = i;
1090 }
1091 DEBUG_ONLY(dead_loop_check(k);)
1092 // Try idealizing again
1093 i = k->Ideal(this, /*can_reshape=*/true);
1094 #ifndef PRODUCT
1095 if( VerifyIterativeGVN )
1096 verify_step(k);
1097 if( i && VerifyOpto ) set_progress();
1098 #endif
1099 }
1100
1101 // If brand new node, make space in type array.
1102 ensure_type_or_null(k);
1103
1104 // See what kind of values 'k' takes on at runtime
1105 const Type *t = k->Value(this);
1106 assert(t != NULL, "value sanity");
1107
1108 // Since I just called 'Value' to compute the set of run-time values
1109 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1110 // cache Value. Later requests for the local phase->type of this Node can
1111 // use the cached Value instead of suffering with 'bottom_type'.
1112 if (t != type_or_null(k)) {
1113 NOT_PRODUCT( set_progress(); )
1114 NOT_PRODUCT( inc_new_values();)
1115 set_type(k, t);
1116 // If k is a TypeNode, capture any more-precise type permanently into Node
1117 k->raise_bottom_type(t);
1118 // Move users of node to worklist
1119 add_users_to_worklist( k );
1120 }
1121
1122 // If 'k' computes a constant, replace it with a constant
1123 if( t->singleton() && !k->is_Con() ) {
1124 NOT_PRODUCT( set_progress(); )
1125 Node *con = makecon(t); // Make a constant
1126 add_users_to_worklist( k );
1127 subsume_node( k, con ); // Everybody using k now uses con
1128 return con;
1129 }
1130
1131 // Now check for Identities
1132 i = k->Identity(this); // Look for a nearby replacement
1133 if( i != k ) { // Found? Return replacement!
1134 NOT_PRODUCT( set_progress(); )
1135 add_users_to_worklist( k );
1136 subsume_node( k, i ); // Everybody using k now uses i
1137 return i;
1138 }
1139
1140 // Global Value Numbering
1141 i = hash_find_insert(k); // Check for pre-existing node
1142 if( i && (i != k) ) {
1143 // Return the pre-existing node if it isn't dead
1144 NOT_PRODUCT( set_progress(); )
1145 add_users_to_worklist( k );
1146 subsume_node( k, i ); // Everybody using k now uses i
1147 return i;
1148 }
1149
1150 // Return Idealized original
1151 return k;
1152 }
1153
1154 //---------------------------------saturate------------------------------------
1155 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1156 const Type* limit_type) const {
1157 return new_type->narrow(old_type);
1158 }
1159
1160 //------------------------------remove_globally_dead_node----------------------
1161 // Kill a globally dead Node. All uses are also globally dead and are
1162 // aggressively trimmed.
1163 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1164 assert(dead != C->root(), "killing root, eh?");
1165 if (dead->is_top()) return;
1166 NOT_PRODUCT( set_progress(); )
1167 // Remove from iterative worklist
1168 _worklist.remove(dead);
1169 if (!dead->is_Con()) { // Don't kill cons but uses
1170 // Remove from hash table
1171 _table.hash_delete( dead );
1172 // Smash all inputs to 'dead', isolating him completely
1173 for( uint i = 0; i < dead->req(); i++ ) {
1174 Node *in = dead->in(i);
1175 if( in ) { // Points to something?
1176 dead->set_req(i,NULL); // Kill the edge
1177 if (in->outcnt() == 0 && in != C->top()) {// Made input go dead?
1178 remove_dead_node(in); // Recursively remove
1179 } else if (in->outcnt() == 1 &&
1180 in->has_special_unique_user()) {
1181 _worklist.push(in->unique_out());
1182 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1183 if( in->Opcode() == Op_Region )
1184 _worklist.push(in);
1185 else if( in->is_Store() ) {
1186 DUIterator_Fast imax, i = in->fast_outs(imax);
1187 _worklist.push(in->fast_out(i));
1188 i++;
1189 if(in->outcnt() == 2) {
1190 _worklist.push(in->fast_out(i));
1191 i++;
1192 }
1193 assert(!(i < imax), "sanity");
1194 }
1195 }
1196 }
1197 }
1198
1199 if (dead->is_macro()) {
1200 C->remove_macro_node(dead);
1201 }
1202 }
1203 // Aggressively kill globally dead uses
1204 // (Cannot use DUIterator_Last because of the indefinite number
1205 // of edge deletions per loop trip.)
1206 while (dead->outcnt() > 0) {
1207 remove_globally_dead_node(dead->raw_out(0));
1208 }
1209 }
1210
1211 //------------------------------subsume_node-----------------------------------
1212 // Remove users from node 'old' and add them to node 'nn'.
1213 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1214 assert( old != hash_find(old), "should already been removed" );
1215 assert( old != C->top(), "cannot subsume top node");
1216 // Copy debug or profile information to the new version:
1217 C->copy_node_notes_to(nn, old);
1218 // Move users of node 'old' to node 'nn'
1219 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1220 Node* use = old->last_out(i); // for each use...
1221 // use might need re-hashing (but it won't if it's a new node)
1222 bool is_in_table = _table.hash_delete( use );
1223 // Update use-def info as well
1224 // We remove all occurrences of old within use->in,
1225 // so as to avoid rehashing any node more than once.
1226 // The hash table probe swamps any outer loop overhead.
1227 uint num_edges = 0;
1228 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1229 if (use->in(j) == old) {
1230 use->set_req(j, nn);
1231 ++num_edges;
1232 }
1233 }
1234 // Insert into GVN hash table if unique
1235 // If a duplicate, 'use' will be cleaned up when pulled off worklist
1236 if( is_in_table ) {
1237 hash_find_insert(use);
1238 }
1239 i -= num_edges; // we deleted 1 or more copies of this edge
1240 }
1241
1242 // Smash all inputs to 'old', isolating him completely
1243 Node *temp = new (C, 1) Node(1);
1244 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1245 remove_dead_node( old );
1246 temp->del_req(0); // Yank bogus edge
1247 #ifndef PRODUCT
1248 if( VerifyIterativeGVN ) {
1249 for ( int i = 0; i < _verify_window_size; i++ ) {
1250 if ( _verify_window[i] == old )
1251 _verify_window[i] = nn;
1252 }
1253 }
1254 #endif
1255 _worklist.remove(temp); // this can be necessary
1256 temp->destruct(); // reuse the _idx of this little guy
1257 }
1258
1259 //------------------------------add_users_to_worklist--------------------------
1260 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1261 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1262 _worklist.push(n->fast_out(i)); // Push on worklist
1263 }
1264 }
1265
1266 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1267 add_users_to_worklist0(n);
1268
1269 // Move users of node to worklist
1270 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1271 Node* use = n->fast_out(i); // Get use
1272
1273 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1274 use->is_Store() ) // Enable store/load same address
1275 add_users_to_worklist0(use);
1276
1277 // If we changed the receiver type to a call, we need to revisit
1278 // the Catch following the call. It's looking for a non-NULL
1279 // receiver to know when to enable the regular fall-through path
1280 // in addition to the NullPtrException path.
1281 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1282 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control);
1283 if (p != NULL) {
1284 add_users_to_worklist0(p);
1285 }
1286 }
1287
1288 if( use->is_Cmp() ) { // Enable CMP/BOOL optimization
1289 add_users_to_worklist(use); // Put Bool on worklist
1290 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1291 // phi merging either 0 or 1 onto the worklist
1292 if (use->outcnt() > 0) {
1293 Node* bol = use->raw_out(0);
1294 if (bol->outcnt() > 0) {
1295 Node* iff = bol->raw_out(0);
1296 if (iff->outcnt() == 2) {
1297 Node* ifproj0 = iff->raw_out(0);
1298 Node* ifproj1 = iff->raw_out(1);
1299 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1300 Node* region0 = ifproj0->raw_out(0);
1301 Node* region1 = ifproj1->raw_out(0);
1302 if( region0 == region1 )
1303 add_users_to_worklist0(region0);
1304 }
1305 }
1306 }
1307 }
1308 }
1309
1310 uint use_op = use->Opcode();
1311 // If changed Cast input, check Phi users for simple cycles
1312 if( use->is_ConstraintCast() || use->Opcode() == Op_CheckCastPP ) {
1313 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1314 Node* u = use->fast_out(i2);
1315 if (u->is_Phi())
1316 _worklist.push(u);
1317 }
1318 }
1319 // If changed LShift inputs, check RShift users for useless sign-ext
1320 if( use_op == Op_LShiftI ) {
1321 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1322 Node* u = use->fast_out(i2);
1323 if (u->Opcode() == Op_RShiftI)
1324 _worklist.push(u);
1325 }
1326 }
1327 // If changed AddP inputs, check Stores for loop invariant
1328 if( use_op == Op_AddP ) {
1329 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1330 Node* u = use->fast_out(i2);
1331 if (u->is_Mem())
1332 _worklist.push(u);
1333 }
1334 }
1335 // If changed initialization activity, check dependent Stores
1336 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1337 InitializeNode* init = use->as_Allocate()->initialization();
1338 if (init != NULL) {
1339 Node* imem = init->proj_out(TypeFunc::Memory);
1340 if (imem != NULL) add_users_to_worklist0(imem);
1341 }
1342 }
1343 if (use_op == Op_Initialize) {
1344 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory);
1345 if (imem != NULL) add_users_to_worklist0(imem);
1346 }
1347 }
1348 }
1349
1350 //=============================================================================
1351 #ifndef PRODUCT
1352 uint PhaseCCP::_total_invokes = 0;
1353 uint PhaseCCP::_total_constants = 0;
1354 #endif
1355 //------------------------------PhaseCCP---------------------------------------
1356 // Conditional Constant Propagation, ala Wegman & Zadeck
1357 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1358 NOT_PRODUCT( clear_constants(); )
1359 assert( _worklist.size() == 0, "" );
1360 // Clear out _nodes from IterGVN. Must be clear to transform call.
1361 _nodes.clear(); // Clear out from IterGVN
1362 analyze();
1363 }
1364
1365 #ifndef PRODUCT
1366 //------------------------------~PhaseCCP--------------------------------------
1367 PhaseCCP::~PhaseCCP() {
1368 inc_invokes();
1369 _total_constants += count_constants();
1370 }
1371 #endif
1372
1373
1374 #ifdef ASSERT
1375 static bool ccp_type_widens(const Type* t, const Type* t0) {
1376 assert(t->meet(t0) == t, "Not monotonic");
1377 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1378 case Type::Int:
1379 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1380 break;
1381 case Type::Long:
1382 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1383 break;
1384 }
1385 return true;
1386 }
1387 #endif //ASSERT
1388
1389 //------------------------------analyze----------------------------------------
1390 void PhaseCCP::analyze() {
1391 // Initialize all types to TOP, optimistic analysis
1392 for (int i = C->unique() - 1; i >= 0; i--) {
1393 _types.map(i,Type::TOP);
1394 }
1395
1396 // Push root onto worklist
1397 Unique_Node_List worklist;
1398 worklist.push(C->root());
1399
1400 // Pull from worklist; compute new value; push changes out.
1401 // This loop is the meat of CCP.
1402 while( worklist.size() ) {
1403 Node *n = worklist.pop();
1404 const Type *t = n->Value(this);
1405 if (t != type(n)) {
1406 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1407 #ifndef PRODUCT
1408 if( TracePhaseCCP ) {
1409 t->dump();
1410 do { tty->print("\t"); } while (tty->position() < 16);
1411 n->dump();
1412 }
1413 #endif
1414 set_type(n, t);
1415 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1416 Node* m = n->fast_out(i); // Get user
1417 if( m->is_Region() ) { // New path to Region? Must recheck Phis too
1418 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1419 Node* p = m->fast_out(i2); // Propagate changes to uses
1420 if( p->bottom_type() != type(p) ) // If not already bottomed out
1421 worklist.push(p); // Propagate change to user
1422 }
1423 }
1424 // If we changed the reciever type to a call, we need to revisit
1425 // the Catch following the call. It's looking for a non-NULL
1426 // receiver to know when to enable the regular fall-through path
1427 // in addition to the NullPtrException path
1428 if (m->is_Call()) {
1429 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1430 Node* p = m->fast_out(i2); // Propagate changes to uses
1431 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1)
1432 worklist.push(p->unique_out());
1433 }
1434 }
1435 if( m->bottom_type() != type(m) ) // If not already bottomed out
1436 worklist.push(m); // Propagate change to user
1437 }
1438 }
1439 }
1440 }
1441
1442 //------------------------------do_transform-----------------------------------
1443 // Top level driver for the recursive transformer
1444 void PhaseCCP::do_transform() {
1445 // Correct leaves of new-space Nodes; they point to old-space.
1446 C->set_root( transform(C->root())->as_Root() );
1447 assert( C->top(), "missing TOP node" );
1448 assert( C->root(), "missing root" );
1449 }
1450
1451 //------------------------------transform--------------------------------------
1452 // Given a Node in old-space, clone him into new-space.
1453 // Convert any of his old-space children into new-space children.
1454 Node *PhaseCCP::transform( Node *n ) {
1455 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1456 if( new_node != NULL )
1457 return new_node; // Been there, done that, return old answer
1458 new_node = transform_once(n); // Check for constant
1459 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1460
1461 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1462 GrowableArray <Node *> trstack(C->unique() >> 1);
1463
1464 trstack.push(new_node); // Process children of cloned node
1465 while ( trstack.is_nonempty() ) {
1466 Node *clone = trstack.pop();
1467 uint cnt = clone->req();
1468 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1469 Node *input = clone->in(i);
1470 if( input != NULL ) { // Ignore NULLs
1471 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1472 if( new_input == NULL ) {
1473 new_input = transform_once(input); // Check for constant
1474 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1475 trstack.push(new_input);
1476 }
1477 assert( new_input == clone->in(i), "insanity check");
1478 }
1479 }
1480 }
1481 return new_node;
1482 }
1483
1484
1485 //------------------------------transform_once---------------------------------
1486 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1487 Node *PhaseCCP::transform_once( Node *n ) {
1488 const Type *t = type(n);
1489 // Constant? Use constant Node instead
1490 if( t->singleton() ) {
1491 Node *nn = n; // Default is to return the original constant
1492 if( t == Type::TOP ) {
1493 // cache my top node on the Compile instance
1494 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1495 C->set_cached_top_node( ConNode::make(C, Type::TOP) );
1496 set_type(C->top(), Type::TOP);
1497 }
1498 nn = C->top();
1499 }
1500 if( !n->is_Con() ) {
1501 if( t != Type::TOP ) {
1502 nn = makecon(t); // ConNode::make(t);
1503 NOT_PRODUCT( inc_constants(); )
1504 } else if( n->is_Region() ) { // Unreachable region
1505 // Note: nn == C->top()
1506 n->set_req(0, NULL); // Cut selfreference
1507 // Eagerly remove dead phis to avoid phis copies creation.
1508 for (DUIterator i = n->outs(); n->has_out(i); i++) {
1509 Node* m = n->out(i);
1510 if( m->is_Phi() ) {
1511 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1512 add_users_to_worklist(m);
1513 hash_delete(m); // Yank from hash before hacking edges
1514 subsume_node(m, nn);
1515 --i; // deleted this phi; rescan starting with next position
1516 }
1517 }
1518 }
1519 add_users_to_worklist(n); // Users of about-to-be-constant 'n'
1520 hash_delete(n); // Removed 'n' from table before subsuming it
1521 subsume_node(n,nn); // Update DefUse edges for new constant
1522 }
1523 return nn;
1524 }
1525
1526 // If x is a TypeNode, capture any more-precise type permanently into Node
1527 if (t != n->bottom_type()) {
1528 hash_delete(n); // changing bottom type may force a rehash
1529 n->raise_bottom_type(t);
1530 _worklist.push(n); // n re-enters the hash table via the worklist
1531 }
1532
1533 // Idealize graph using DU info. Must clone() into new-space.
1534 // DU info is generally used to show profitability, progress or safety
1535 // (but generally not needed for correctness).
1536 Node *nn = n->Ideal_DU_postCCP(this);
1537
1538 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1539 switch( n->Opcode() ) {
1540 case Op_FastLock: // Revisit FastLocks for lock coarsening
1541 case Op_If:
1542 case Op_CountedLoopEnd:
1543 case Op_Region:
1544 case Op_Loop:
1545 case Op_CountedLoop:
1546 case Op_Conv2B:
1547 case Op_Opaque1:
1548 case Op_Opaque2:
1549 _worklist.push(n);
1550 break;
1551 default:
1552 break;
1553 }
1554 if( nn ) {
1555 _worklist.push(n);
1556 // Put users of 'n' onto worklist for second igvn transform
1557 add_users_to_worklist(n);
1558 return nn;
1559 }
1560
1561 return n;
1562 }
1563
1564 //---------------------------------saturate------------------------------------
1565 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
1566 const Type* limit_type) const {
1567 const Type* wide_type = new_type->widen(old_type);
1568 if (wide_type != new_type) { // did we widen?
1569 // If so, we may have widened beyond the limit type. Clip it back down.
1570 new_type = wide_type->filter(limit_type);
1571 }
1572 return new_type;
1573 }
1574
1575 //------------------------------print_statistics-------------------------------
1576 #ifndef PRODUCT
1577 void PhaseCCP::print_statistics() {
1578 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
1579 }
1580 #endif
1581
1582
1583 //=============================================================================
1584 #ifndef PRODUCT
1585 uint PhasePeephole::_total_peepholes = 0;
1586 #endif
1587 //------------------------------PhasePeephole----------------------------------
1588 // Conditional Constant Propagation, ala Wegman & Zadeck
1589 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
1590 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
1591 NOT_PRODUCT( clear_peepholes(); )
1592 }
1593
1594 #ifndef PRODUCT
1595 //------------------------------~PhasePeephole---------------------------------
1596 PhasePeephole::~PhasePeephole() {
1597 _total_peepholes += count_peepholes();
1598 }
1599 #endif
1600
1601 //------------------------------transform--------------------------------------
1602 Node *PhasePeephole::transform( Node *n ) {
1603 ShouldNotCallThis();
1604 return NULL;
1605 }
1606
1607 //------------------------------do_transform-----------------------------------
1608 void PhasePeephole::do_transform() {
1609 bool method_name_not_printed = true;
1610
1611 // Examine each basic block
1612 for( uint block_number = 1; block_number < _cfg._num_blocks; ++block_number ) {
1613 Block *block = _cfg._blocks[block_number];
1614 bool block_not_printed = true;
1615
1616 // and each instruction within a block
1617 uint end_index = block->_nodes.size();
1618 // block->end_idx() not valid after PhaseRegAlloc
1619 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
1620 Node *n = block->_nodes.at(instruction_index);
1621 if( n->is_Mach() ) {
1622 MachNode *m = n->as_Mach();
1623 int deleted_count = 0;
1624 // check for peephole opportunities
1625 MachNode *m2 = m->peephole( block, instruction_index, _regalloc, deleted_count, C );
1626 if( m2 != NULL ) {
1627 #ifndef PRODUCT
1628 if( PrintOptoPeephole ) {
1629 // Print method, first time only
1630 if( C->method() && method_name_not_printed ) {
1631 C->method()->print_short_name(); tty->cr();
1632 method_name_not_printed = false;
1633 }
1634 // Print this block
1635 if( Verbose && block_not_printed) {
1636 tty->print_cr("in block");
1637 block->dump();
1638 block_not_printed = false;
1639 }
1640 // Print instructions being deleted
1641 for( int i = (deleted_count - 1); i >= 0; --i ) {
1642 block->_nodes.at(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
1643 }
1644 tty->print_cr("replaced with");
1645 // Print new instruction
1646 m2->format(_regalloc);
1647 tty->print("\n\n");
1648 }
1649 #endif
1650 // Remove old nodes from basic block and update instruction_index
1651 // (old nodes still exist and may have edges pointing to them
1652 // as register allocation info is stored in the allocator using
1653 // the node index to live range mappings.)
1654 uint safe_instruction_index = (instruction_index - deleted_count);
1655 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
1656 block->_nodes.remove( instruction_index );
1657 }
1658 // install new node after safe_instruction_index
1659 block->_nodes.insert( safe_instruction_index + 1, m2 );
1660 end_index = block->_nodes.size() - 1; // Recompute new block size
1661 NOT_PRODUCT( inc_peepholes(); )
1662 }
1663 }
1664 }
1665 }
1666 }
1667
1668 //------------------------------print_statistics-------------------------------
1669 #ifndef PRODUCT
1670 void PhasePeephole::print_statistics() {
1671 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
1672 }
1673 #endif
1674
1675
1676 //=============================================================================
1677 //------------------------------set_req_X--------------------------------------
1678 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
1679 assert( is_not_dead(n), "can not use dead node");
1680 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
1681 Node *old = in(i);
1682 set_req(i, n);
1683
1684 // old goes dead?
1685 if( old ) {
1686 switch (old->outcnt()) {
1687 case 0: // Kill all his inputs, and recursively kill other dead nodes.
1688 if (!old->is_top())
1689 igvn->remove_dead_node( old );
1690 break;
1691 case 1:
1692 if( old->is_Store() || old->has_special_unique_user() )
1693 igvn->add_users_to_worklist( old );
1694 break;
1695 case 2:
1696 if( old->is_Store() )
1697 igvn->add_users_to_worklist( old );
1698 if( old->Opcode() == Op_Region )
1699 igvn->_worklist.push(old);
1700 break;
1701 case 3:
1702 if( old->Opcode() == Op_Region ) {
1703 igvn->_worklist.push(old);
1704 igvn->add_users_to_worklist( old );
1705 }
1706 break;
1707 default:
1708 break;
1709 }
1710 }
1711
1712 }
1713
1714 //-------------------------------replace_by-----------------------------------
1715 // Using def-use info, replace one node for another. Follow the def-use info
1716 // to all users of the OLD node. Then make all uses point to the NEW node.
1717 void Node::replace_by(Node *new_node) {
1718 assert(!is_top(), "top node has no DU info");
1719 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
1720 Node* use = last_out(i);
1721 uint uses_found = 0;
1722 for (uint j = 0; j < use->len(); j++) {
1723 if (use->in(j) == this) {
1724 if (j < use->req())
1725 use->set_req(j, new_node);
1726 else use->set_prec(j, new_node);
1727 uses_found++;
1728 }
1729 }
1730 i -= uses_found; // we deleted 1 or more copies of this edge
1731 }
1732 }
1733
1734 //=============================================================================
1735 //-----------------------------------------------------------------------------
1736 void Type_Array::grow( uint i ) {
1737 if( !_max ) {
1738 _max = 1;
1739 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
1740 _types[0] = NULL;
1741 }
1742 uint old = _max;
1743 while( i >= _max ) _max <<= 1; // Double to fit
1744 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
1745 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
1746 }
1747
1748 //------------------------------dump-------------------------------------------
1749 #ifndef PRODUCT
1750 void Type_Array::dump() const {
1751 uint max = Size();
1752 for( uint i = 0; i < max; i++ ) {
1753 if( _types[i] != NULL ) {
1754 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
1755 }
1756 }
1757 }
1758 #endif