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src/share/vm/opto/phaseX.cpp@2aff40cb4703
src/share/vm/opto/phaseX.cpp
Tue, 27 Nov 2012 17:24:15 -0800
- author
- bharadwaj
- date
- Tue, 27 Nov 2012 17:24:15 -0800
- changeset 4315
- 2aff40cb4703
- parent 4153
- b9a9ed0f8eeb
- child 4409
- d092d1b31229
- permissions
- -rw-r--r--
7092905: C2: Keep track of the number of dead nodes
Summary: keep an (almost) accurate running count of the reachable (live) flow graph nodes.
Reviewed-by: kvn, twisti, jrose, vlivanov
1 /*
2 * Copyright (c) 1997, 2012, 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 */
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"
39 //=============================================================================
40 #define NODE_HASH_MINIMUM_SIZE 255
41 //------------------------------NodeHash---------------------------------------
42 NodeHash::NodeHash(uint est_max_size) :
43 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
44 _a(Thread::current()->resource_area()),
45 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), // (Node**)_a->Amalloc(_max * sizeof(Node*)) ),
46 _inserts(0), _insert_limit( insert_limit() ),
47 _look_probes(0), _lookup_hits(0), _lookup_misses(0),
48 _total_insert_probes(0), _total_inserts(0),
49 _insert_probes(0), _grows(0) {
50 // _sentinel must be in the current node space
51 _sentinel = new (Compile::current()) ProjNode(NULL, TypeFunc::Control);
52 memset(_table,0,sizeof(Node*)*_max);
53 }
55 //------------------------------NodeHash---------------------------------------
56 NodeHash::NodeHash(Arena *arena, uint est_max_size) :
57 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
58 _a(arena),
59 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ),
60 _inserts(0), _insert_limit( insert_limit() ),
61 _look_probes(0), _lookup_hits(0), _lookup_misses(0),
62 _delete_probes(0), _delete_hits(0), _delete_misses(0),
63 _total_insert_probes(0), _total_inserts(0),
64 _insert_probes(0), _grows(0) {
65 // _sentinel must be in the current node space
66 _sentinel = new (Compile::current()) ProjNode(NULL, TypeFunc::Control);
67 memset(_table,0,sizeof(Node*)*_max);
68 }
70 //------------------------------NodeHash---------------------------------------
71 NodeHash::NodeHash(NodeHash *nh) {
72 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
73 // just copy in all the fields
74 *this = *nh;
75 // nh->_sentinel must be in the current node space
76 }
78 //------------------------------hash_find--------------------------------------
79 // Find in hash table
80 Node *NodeHash::hash_find( const Node *n ) {
81 // ((Node*)n)->set_hash( n->hash() );
82 uint hash = n->hash();
83 if (hash == Node::NO_HASH) {
84 debug_only( _lookup_misses++ );
85 return NULL;
86 }
87 uint key = hash & (_max-1);
88 uint stride = key | 0x01;
89 debug_only( _look_probes++ );
90 Node *k = _table[key]; // Get hashed value
91 if( !k ) { // ?Miss?
92 debug_only( _lookup_misses++ );
93 return NULL; // Miss!
94 }
96 int op = n->Opcode();
97 uint req = n->req();
98 while( 1 ) { // While probing hash table
99 if( k->req() == req && // Same count of inputs
100 k->Opcode() == op ) { // Same Opcode
101 for( uint i=0; i<req; i++ )
102 if( n->in(i)!=k->in(i)) // Different inputs?
103 goto collision; // "goto" is a speed hack...
104 if( n->cmp(*k) ) { // Check for any special bits
105 debug_only( _lookup_hits++ );
106 return k; // Hit!
107 }
108 }
109 collision:
110 debug_only( _look_probes++ );
111 key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime
112 k = _table[key]; // Get hashed value
113 if( !k ) { // ?Miss?
114 debug_only( _lookup_misses++ );
115 return NULL; // Miss!
116 }
117 }
118 ShouldNotReachHere();
119 return NULL;
120 }
122 //------------------------------hash_find_insert-------------------------------
123 // Find in hash table, insert if not already present
124 // Used to preserve unique entries in hash table
125 Node *NodeHash::hash_find_insert( Node *n ) {
126 // n->set_hash( );
127 uint hash = n->hash();
128 if (hash == Node::NO_HASH) {
129 debug_only( _lookup_misses++ );
130 return NULL;
131 }
132 uint key = hash & (_max-1);
133 uint stride = key | 0x01; // stride must be relatively prime to table siz
134 uint first_sentinel = 0; // replace a sentinel if seen.
135 debug_only( _look_probes++ );
136 Node *k = _table[key]; // Get hashed value
137 if( !k ) { // ?Miss?
138 debug_only( _lookup_misses++ );
139 _table[key] = n; // Insert into table!
140 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
141 check_grow(); // Grow table if insert hit limit
142 return NULL; // Miss!
143 }
144 else if( k == _sentinel ) {
145 first_sentinel = key; // Can insert here
146 }
148 int op = n->Opcode();
149 uint req = n->req();
150 while( 1 ) { // While probing hash table
151 if( k->req() == req && // Same count of inputs
152 k->Opcode() == op ) { // Same Opcode
153 for( uint i=0; i<req; i++ )
154 if( n->in(i)!=k->in(i)) // Different inputs?
155 goto collision; // "goto" is a speed hack...
156 if( n->cmp(*k) ) { // Check for any special bits
157 debug_only( _lookup_hits++ );
158 return k; // Hit!
159 }
160 }
161 collision:
162 debug_only( _look_probes++ );
163 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
164 k = _table[key]; // Get hashed value
165 if( !k ) { // ?Miss?
166 debug_only( _lookup_misses++ );
167 key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel?
168 _table[key] = n; // Insert into table!
169 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
170 check_grow(); // Grow table if insert hit limit
171 return NULL; // Miss!
172 }
173 else if( first_sentinel == 0 && k == _sentinel ) {
174 first_sentinel = key; // Can insert here
175 }
177 }
178 ShouldNotReachHere();
179 return NULL;
180 }
182 //------------------------------hash_insert------------------------------------
183 // Insert into hash table
184 void NodeHash::hash_insert( Node *n ) {
185 // // "conflict" comments -- print nodes that conflict
186 // bool conflict = false;
187 // n->set_hash();
188 uint hash = n->hash();
189 if (hash == Node::NO_HASH) {
190 return;
191 }
192 check_grow();
193 uint key = hash & (_max-1);
194 uint stride = key | 0x01;
196 while( 1 ) { // While probing hash table
197 debug_only( _insert_probes++ );
198 Node *k = _table[key]; // Get hashed value
199 if( !k || (k == _sentinel) ) break; // Found a slot
200 assert( k != n, "already inserted" );
201 // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print(" conflict: "); k->dump(); conflict = true; }
202 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
203 }
204 _table[key] = n; // Insert into table!
205 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
206 // if( conflict ) { n->dump(); }
207 }
209 //------------------------------hash_delete------------------------------------
210 // Replace in hash table with sentinel
211 bool NodeHash::hash_delete( const Node *n ) {
212 Node *k;
213 uint hash = n->hash();
214 if (hash == Node::NO_HASH) {
215 debug_only( _delete_misses++ );
216 return false;
217 }
218 uint key = hash & (_max-1);
219 uint stride = key | 0x01;
220 debug_only( uint counter = 0; );
221 for( ; /* (k != NULL) && (k != _sentinel) */; ) {
222 debug_only( counter++ );
223 debug_only( _delete_probes++ );
224 k = _table[key]; // Get hashed value
225 if( !k ) { // Miss?
226 debug_only( _delete_misses++ );
227 #ifdef ASSERT
228 if( VerifyOpto ) {
229 for( uint i=0; i < _max; i++ )
230 assert( _table[i] != n, "changed edges with rehashing" );
231 }
232 #endif
233 return false; // Miss! Not in chain
234 }
235 else if( n == k ) {
236 debug_only( _delete_hits++ );
237 _table[key] = _sentinel; // Hit! Label as deleted entry
238 debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table.
239 return true;
240 }
241 else {
242 // collision: move through table with prime offset
243 key = (key + stride/*7*/) & (_max-1);
244 assert( counter <= _insert_limit, "Cycle in hash-table");
245 }
246 }
247 ShouldNotReachHere();
248 return false;
249 }
251 //------------------------------round_up---------------------------------------
252 // Round up to nearest power of 2
253 uint NodeHash::round_up( uint x ) {
254 x += (x>>2); // Add 25% slop
255 if( x <16 ) return 16; // Small stuff
256 uint i=16;
257 while( i < x ) i <<= 1; // Double to fit
258 return i; // Return hash table size
259 }
261 //------------------------------grow-------------------------------------------
262 // Grow _table to next power of 2 and insert old entries
263 void NodeHash::grow() {
264 // Record old state
265 uint old_max = _max;
266 Node **old_table = _table;
267 // Construct new table with twice the space
268 _grows++;
269 _total_inserts += _inserts;
270 _total_insert_probes += _insert_probes;
271 _inserts = 0;
272 _insert_probes = 0;
273 _max = _max << 1;
274 _table = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) );
275 memset(_table,0,sizeof(Node*)*_max);
276 _insert_limit = insert_limit();
277 // Insert old entries into the new table
278 for( uint i = 0; i < old_max; i++ ) {
279 Node *m = *old_table++;
280 if( !m || m == _sentinel ) continue;
281 debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table.
282 hash_insert(m);
283 }
284 }
286 //------------------------------clear------------------------------------------
287 // Clear all entries in _table to NULL but keep storage
288 void NodeHash::clear() {
289 #ifdef ASSERT
290 // Unlock all nodes upon removal from table.
291 for (uint i = 0; i < _max; i++) {
292 Node* n = _table[i];
293 if (!n || n == _sentinel) continue;
294 n->exit_hash_lock();
295 }
296 #endif
298 memset( _table, 0, _max * sizeof(Node*) );
299 }
301 //-----------------------remove_useless_nodes----------------------------------
302 // Remove useless nodes from value table,
303 // implementation does not depend on hash function
304 void NodeHash::remove_useless_nodes(VectorSet &useful) {
306 // Dead nodes in the hash table inherited from GVN should not replace
307 // existing nodes, remove dead nodes.
308 uint max = size();
309 Node *sentinel_node = sentinel();
310 for( uint i = 0; i < max; ++i ) {
311 Node *n = at(i);
312 if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) {
313 debug_only(n->exit_hash_lock()); // Unlock the node when removed
314 _table[i] = sentinel_node; // Replace with placeholder
315 }
316 }
317 }
319 #ifndef PRODUCT
320 //------------------------------dump-------------------------------------------
321 // Dump statistics for the hash table
322 void NodeHash::dump() {
323 _total_inserts += _inserts;
324 _total_insert_probes += _insert_probes;
325 if (PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0)) {
326 if (WizardMode) {
327 for (uint i=0; i<_max; i++) {
328 if (_table[i])
329 tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx);
330 }
331 }
332 tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max);
333 tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0);
334 tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses));
335 tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts);
336 // sentinels increase lookup cost, but not insert cost
337 assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function");
338 assert( _inserts+(_inserts>>3) < _max, "table too full" );
339 assert( _inserts*3+100 >= _insert_probes, "bad hash function" );
340 }
341 }
343 Node *NodeHash::find_index(uint idx) { // For debugging
344 // Find an entry by its index value
345 for( uint i = 0; i < _max; i++ ) {
346 Node *m = _table[i];
347 if( !m || m == _sentinel ) continue;
348 if( m->_idx == (uint)idx ) return m;
349 }
350 return NULL;
351 }
352 #endif
354 #ifdef ASSERT
355 NodeHash::~NodeHash() {
356 // Unlock all nodes upon destruction of table.
357 if (_table != (Node**)badAddress) clear();
358 }
360 void NodeHash::operator=(const NodeHash& nh) {
361 // Unlock all nodes upon replacement of table.
362 if (&nh == this) return;
363 if (_table != (Node**)badAddress) clear();
364 memcpy(this, &nh, sizeof(*this));
365 // Do not increment hash_lock counts again.
366 // Instead, be sure we never again use the source table.
367 ((NodeHash*)&nh)->_table = (Node**)badAddress;
368 }
371 #endif
374 //=============================================================================
375 //------------------------------PhaseRemoveUseless-----------------------------
376 // 1) Use a breadthfirst walk to collect useful nodes reachable from root.
377 PhaseRemoveUseless::PhaseRemoveUseless( PhaseGVN *gvn, Unique_Node_List *worklist ) : Phase(Remove_Useless),
378 _useful(Thread::current()->resource_area()) {
380 // Implementation requires 'UseLoopSafepoints == true' and an edge from root
381 // to each SafePointNode at a backward branch. Inserted in add_safepoint().
382 if( !UseLoopSafepoints || !OptoRemoveUseless ) return;
384 // Identify nodes that are reachable from below, useful.
385 C->identify_useful_nodes(_useful);
386 // Update dead node list
387 C->update_dead_node_list(_useful);
389 // Remove all useless nodes from PhaseValues' recorded types
390 // Must be done before disconnecting nodes to preserve hash-table-invariant
391 gvn->remove_useless_nodes(_useful.member_set());
393 // Remove all useless nodes from future worklist
394 worklist->remove_useless_nodes(_useful.member_set());
396 // Disconnect 'useless' nodes that are adjacent to useful nodes
397 C->remove_useless_nodes(_useful);
399 // Remove edges from "root" to each SafePoint at a backward branch.
400 // They were inserted during parsing (see add_safepoint()) to make infinite
401 // loops without calls or exceptions visible to root, i.e., useful.
402 Node *root = C->root();
403 if( root != NULL ) {
404 for( uint i = root->req(); i < root->len(); ++i ) {
405 Node *n = root->in(i);
406 if( n != NULL && n->is_SafePoint() ) {
407 root->rm_prec(i);
408 --i;
409 }
410 }
411 }
412 }
415 //=============================================================================
416 //------------------------------PhaseTransform---------------------------------
417 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
418 _arena(Thread::current()->resource_area()),
419 _nodes(_arena),
420 _types(_arena)
421 {
422 init_con_caches();
423 #ifndef PRODUCT
424 clear_progress();
425 clear_transforms();
426 set_allow_progress(true);
427 #endif
428 // Force allocation for currently existing nodes
429 _types.map(C->unique(), NULL);
430 }
432 //------------------------------PhaseTransform---------------------------------
433 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
434 _arena(arena),
435 _nodes(arena),
436 _types(arena)
437 {
438 init_con_caches();
439 #ifndef PRODUCT
440 clear_progress();
441 clear_transforms();
442 set_allow_progress(true);
443 #endif
444 // Force allocation for currently existing nodes
445 _types.map(C->unique(), NULL);
446 }
448 //------------------------------PhaseTransform---------------------------------
449 // Initialize with previously generated type information
450 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
451 _arena(pt->_arena),
452 _nodes(pt->_nodes),
453 _types(pt->_types)
454 {
455 init_con_caches();
456 #ifndef PRODUCT
457 clear_progress();
458 clear_transforms();
459 set_allow_progress(true);
460 #endif
461 }
463 void PhaseTransform::init_con_caches() {
464 memset(_icons,0,sizeof(_icons));
465 memset(_lcons,0,sizeof(_lcons));
466 memset(_zcons,0,sizeof(_zcons));
467 }
470 //--------------------------------find_int_type--------------------------------
471 const TypeInt* PhaseTransform::find_int_type(Node* n) {
472 if (n == NULL) return NULL;
473 // Call type_or_null(n) to determine node's type since we might be in
474 // parse phase and call n->Value() may return wrong type.
475 // (For example, a phi node at the beginning of loop parsing is not ready.)
476 const Type* t = type_or_null(n);
477 if (t == NULL) return NULL;
478 return t->isa_int();
479 }
482 //-------------------------------find_long_type--------------------------------
483 const TypeLong* PhaseTransform::find_long_type(Node* n) {
484 if (n == NULL) return NULL;
485 // (See comment above on type_or_null.)
486 const Type* t = type_or_null(n);
487 if (t == NULL) return NULL;
488 return t->isa_long();
489 }
492 #ifndef PRODUCT
493 void PhaseTransform::dump_old2new_map() const {
494 _nodes.dump();
495 }
497 void PhaseTransform::dump_new( uint nidx ) const {
498 for( uint i=0; i<_nodes.Size(); i++ )
499 if( _nodes[i] && _nodes[i]->_idx == nidx ) {
500 _nodes[i]->dump();
501 tty->cr();
502 tty->print_cr("Old index= %d",i);
503 return;
504 }
505 tty->print_cr("Node %d not found in the new indices", nidx);
506 }
508 //------------------------------dump_types-------------------------------------
509 void PhaseTransform::dump_types( ) const {
510 _types.dump();
511 }
513 //------------------------------dump_nodes_and_types---------------------------
514 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
515 VectorSet visited(Thread::current()->resource_area());
516 dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
517 }
519 //------------------------------dump_nodes_and_types_recur---------------------
520 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
521 if( !n ) return;
522 if( depth == 0 ) return;
523 if( visited.test_set(n->_idx) ) return;
524 for( uint i=0; i<n->len(); i++ ) {
525 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
526 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
527 }
528 n->dump();
529 if (type_or_null(n) != NULL) {
530 tty->print(" "); type(n)->dump(); tty->cr();
531 }
532 }
534 #endif
537 //=============================================================================
538 //------------------------------PhaseValues------------------------------------
539 // Set minimum table size to "255"
540 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
541 NOT_PRODUCT( clear_new_values(); )
542 }
544 //------------------------------PhaseValues------------------------------------
545 // Set minimum table size to "255"
546 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
547 _table(&ptv->_table) {
548 NOT_PRODUCT( clear_new_values(); )
549 }
551 //------------------------------PhaseValues------------------------------------
552 // Used by +VerifyOpto. Clear out hash table but copy _types array.
553 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
554 _table(ptv->arena(),ptv->_table.size()) {
555 NOT_PRODUCT( clear_new_values(); )
556 }
558 //------------------------------~PhaseValues-----------------------------------
559 #ifndef PRODUCT
560 PhaseValues::~PhaseValues() {
561 _table.dump();
563 // Statistics for value progress and efficiency
564 if( PrintCompilation && Verbose && WizardMode ) {
565 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
566 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values());
567 if( made_transforms() != 0 ) {
568 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() );
569 } else {
570 tty->cr();
571 }
572 }
573 }
574 #endif
576 //------------------------------makecon----------------------------------------
577 ConNode* PhaseTransform::makecon(const Type *t) {
578 assert(t->singleton(), "must be a constant");
579 assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
580 switch (t->base()) { // fast paths
581 case Type::Half:
582 case Type::Top: return (ConNode*) C->top();
583 case Type::Int: return intcon( t->is_int()->get_con() );
584 case Type::Long: return longcon( t->is_long()->get_con() );
585 }
586 if (t->is_zero_type())
587 return zerocon(t->basic_type());
588 return uncached_makecon(t);
589 }
591 //--------------------------uncached_makecon-----------------------------------
592 // Make an idealized constant - one of ConINode, ConPNode, etc.
593 ConNode* PhaseValues::uncached_makecon(const Type *t) {
594 assert(t->singleton(), "must be a constant");
595 ConNode* x = ConNode::make(C, t);
596 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
597 if (k == NULL) {
598 set_type(x, t); // Missed, provide type mapping
599 GrowableArray<Node_Notes*>* nna = C->node_note_array();
600 if (nna != NULL) {
601 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
602 loc->clear(); // do not put debug info on constants
603 }
604 } else {
605 x->destruct(); // Hit, destroy duplicate constant
606 x = k; // use existing constant
607 }
608 return x;
609 }
611 //------------------------------intcon-----------------------------------------
612 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
613 ConINode* PhaseTransform::intcon(int i) {
614 // Small integer? Check cache! Check that cached node is not dead
615 if (i >= _icon_min && i <= _icon_max) {
616 ConINode* icon = _icons[i-_icon_min];
617 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
618 return icon;
619 }
620 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
621 assert(icon->is_Con(), "");
622 if (i >= _icon_min && i <= _icon_max)
623 _icons[i-_icon_min] = icon; // Cache small integers
624 return icon;
625 }
627 //------------------------------longcon----------------------------------------
628 // Fast long constant.
629 ConLNode* PhaseTransform::longcon(jlong l) {
630 // Small integer? Check cache! Check that cached node is not dead
631 if (l >= _lcon_min && l <= _lcon_max) {
632 ConLNode* lcon = _lcons[l-_lcon_min];
633 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
634 return lcon;
635 }
636 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
637 assert(lcon->is_Con(), "");
638 if (l >= _lcon_min && l <= _lcon_max)
639 _lcons[l-_lcon_min] = lcon; // Cache small integers
640 return lcon;
641 }
643 //------------------------------zerocon-----------------------------------------
644 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
645 ConNode* PhaseTransform::zerocon(BasicType bt) {
646 assert((uint)bt <= _zcon_max, "domain check");
647 ConNode* zcon = _zcons[bt];
648 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
649 return zcon;
650 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
651 _zcons[bt] = zcon;
652 return zcon;
653 }
657 //=============================================================================
658 //------------------------------transform--------------------------------------
659 // Return a node which computes the same function as this node, but in a
660 // faster or cheaper fashion.
661 Node *PhaseGVN::transform( Node *n ) {
662 return transform_no_reclaim(n);
663 }
665 //------------------------------transform--------------------------------------
666 // Return a node which computes the same function as this node, but
667 // in a faster or cheaper fashion.
668 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
669 NOT_PRODUCT( set_transforms(); )
671 // Apply the Ideal call in a loop until it no longer applies
672 Node *k = n;
673 NOT_PRODUCT( uint loop_count = 0; )
674 while( 1 ) {
675 Node *i = k->Ideal(this, /*can_reshape=*/false);
676 if( !i ) break;
677 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
678 k = i;
679 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
680 }
681 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
684 // If brand new node, make space in type array.
685 ensure_type_or_null(k);
687 // Since I just called 'Value' to compute the set of run-time values
688 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
689 // cache Value. Later requests for the local phase->type of this Node can
690 // use the cached Value instead of suffering with 'bottom_type'.
691 const Type *t = k->Value(this); // Get runtime Value set
692 assert(t != NULL, "value sanity");
693 if (type_or_null(k) != t) {
694 #ifndef PRODUCT
695 // Do not count initial visit to node as a transformation
696 if (type_or_null(k) == NULL) {
697 inc_new_values();
698 set_progress();
699 }
700 #endif
701 set_type(k, t);
702 // If k is a TypeNode, capture any more-precise type permanently into Node
703 k->raise_bottom_type(t);
704 }
706 if( t->singleton() && !k->is_Con() ) {
707 NOT_PRODUCT( set_progress(); )
708 return makecon(t); // Turn into a constant
709 }
711 // Now check for Identities
712 Node *i = k->Identity(this); // Look for a nearby replacement
713 if( i != k ) { // Found? Return replacement!
714 NOT_PRODUCT( set_progress(); )
715 return i;
716 }
718 // Global Value Numbering
719 i = hash_find_insert(k); // Insert if new
720 if( i && (i != k) ) {
721 // Return the pre-existing node
722 NOT_PRODUCT( set_progress(); )
723 return i;
724 }
726 // Return Idealized original
727 return k;
728 }
730 #ifdef ASSERT
731 //------------------------------dead_loop_check--------------------------------
732 // Check for a simple dead loop when a data node references itself directly
733 // or through an other data node excluding cons and phis.
734 void PhaseGVN::dead_loop_check( Node *n ) {
735 // Phi may reference itself in a loop
736 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
737 // Do 2 levels check and only data inputs.
738 bool no_dead_loop = true;
739 uint cnt = n->req();
740 for (uint i = 1; i < cnt && no_dead_loop; i++) {
741 Node *in = n->in(i);
742 if (in == n) {
743 no_dead_loop = false;
744 } else if (in != NULL && !in->is_dead_loop_safe()) {
745 uint icnt = in->req();
746 for (uint j = 1; j < icnt && no_dead_loop; j++) {
747 if (in->in(j) == n || in->in(j) == in)
748 no_dead_loop = false;
749 }
750 }
751 }
752 if (!no_dead_loop) n->dump(3);
753 assert(no_dead_loop, "dead loop detected");
754 }
755 }
756 #endif
758 //=============================================================================
759 //------------------------------PhaseIterGVN-----------------------------------
760 // Initialize hash table to fresh and clean for +VerifyOpto
761 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ),
762 _stack(C->unique() >> 1),
763 _delay_transform(false) {
764 }
766 //------------------------------PhaseIterGVN-----------------------------------
767 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
768 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
769 _worklist( igvn->_worklist ),
770 _stack( igvn->_stack ),
771 _delay_transform(igvn->_delay_transform)
772 {
773 }
775 //------------------------------PhaseIterGVN-----------------------------------
776 // Initialize with previous PhaseGVN info from Parser
777 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
778 _worklist(*C->for_igvn()),
779 _stack(C->unique() >> 1),
780 _delay_transform(false)
781 {
782 uint max;
784 // Dead nodes in the hash table inherited from GVN were not treated as
785 // roots during def-use info creation; hence they represent an invisible
786 // use. Clear them out.
787 max = _table.size();
788 for( uint i = 0; i < max; ++i ) {
789 Node *n = _table.at(i);
790 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
791 if( n->is_top() ) continue;
792 assert( false, "Parse::remove_useless_nodes missed this node");
793 hash_delete(n);
794 }
795 }
797 // Any Phis or Regions on the worklist probably had uses that could not
798 // make more progress because the uses were made while the Phis and Regions
799 // were in half-built states. Put all uses of Phis and Regions on worklist.
800 max = _worklist.size();
801 for( uint j = 0; j < max; j++ ) {
802 Node *n = _worklist.at(j);
803 uint uop = n->Opcode();
804 if( uop == Op_Phi || uop == Op_Region ||
805 n->is_Type() ||
806 n->is_Mem() )
807 add_users_to_worklist(n);
808 }
809 }
812 #ifndef PRODUCT
813 void PhaseIterGVN::verify_step(Node* n) {
814 _verify_window[_verify_counter % _verify_window_size] = n;
815 ++_verify_counter;
816 ResourceMark rm;
817 ResourceArea *area = Thread::current()->resource_area();
818 VectorSet old_space(area), new_space(area);
819 if (C->unique() < 1000 ||
820 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
821 ++_verify_full_passes;
822 Node::verify_recur(C->root(), -1, old_space, new_space);
823 }
824 const int verify_depth = 4;
825 for ( int i = 0; i < _verify_window_size; i++ ) {
826 Node* n = _verify_window[i];
827 if ( n == NULL ) continue;
828 if( n->in(0) == NodeSentinel ) { // xform_idom
829 _verify_window[i] = n->in(1);
830 --i; continue;
831 }
832 // Typical fanout is 1-2, so this call visits about 6 nodes.
833 Node::verify_recur(n, verify_depth, old_space, new_space);
834 }
835 }
836 #endif
839 //------------------------------init_worklist----------------------------------
840 // Initialize worklist for each node.
841 void PhaseIterGVN::init_worklist( Node *n ) {
842 if( _worklist.member(n) ) return;
843 _worklist.push(n);
844 uint cnt = n->req();
845 for( uint i =0 ; i < cnt; i++ ) {
846 Node *m = n->in(i);
847 if( m ) init_worklist(m);
848 }
849 }
851 //------------------------------optimize---------------------------------------
852 void PhaseIterGVN::optimize() {
853 debug_only(uint num_processed = 0;);
854 #ifndef PRODUCT
855 {
856 _verify_counter = 0;
857 _verify_full_passes = 0;
858 for ( int i = 0; i < _verify_window_size; i++ ) {
859 _verify_window[i] = NULL;
860 }
861 }
862 #endif
864 #ifdef ASSERT
865 Node* prev = NULL;
866 uint rep_cnt = 0;
867 #endif
868 uint loop_count = 0;
870 // Pull from worklist; transform node;
871 // If node has changed: update edge info and put uses on worklist.
872 while( _worklist.size() ) {
873 if (C->check_node_count(NodeLimitFudgeFactor * 2,
874 "out of nodes optimizing method")) {
875 return;
876 }
877 Node *n = _worklist.pop();
878 if (++loop_count >= K * C->unique()) {
879 debug_only(n->dump(4);)
880 assert(false, "infinite loop in PhaseIterGVN::optimize");
881 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
882 return;
883 }
884 #ifdef ASSERT
885 if (n == prev) {
886 if (++rep_cnt > 3) {
887 n->dump(4);
888 assert(false, "loop in Ideal transformation");
889 }
890 } else {
891 rep_cnt = 0;
892 }
893 prev = n;
894 #endif
895 if (TraceIterativeGVN && Verbose) {
896 tty->print(" Pop ");
897 NOT_PRODUCT( n->dump(); )
898 debug_only(if( (num_processed++ % 100) == 0 ) _worklist.print_set();)
899 }
901 if (n->outcnt() != 0) {
903 #ifndef PRODUCT
904 uint wlsize = _worklist.size();
905 const Type* oldtype = type_or_null(n);
906 #endif //PRODUCT
908 Node *nn = transform_old(n);
910 #ifndef PRODUCT
911 if (TraceIterativeGVN) {
912 const Type* newtype = type_or_null(n);
913 if (nn != n) {
914 // print old node
915 tty->print("< ");
916 if (oldtype != newtype && oldtype != NULL) {
917 oldtype->dump();
918 }
919 do { tty->print("\t"); } while (tty->position() < 16);
920 tty->print("<");
921 n->dump();
922 }
923 if (oldtype != newtype || nn != n) {
924 // print new node and/or new type
925 if (oldtype == NULL) {
926 tty->print("* ");
927 } else if (nn != n) {
928 tty->print("> ");
929 } else {
930 tty->print("= ");
931 }
932 if (newtype == NULL) {
933 tty->print("null");
934 } else {
935 newtype->dump();
936 }
937 do { tty->print("\t"); } while (tty->position() < 16);
938 nn->dump();
939 }
940 if (Verbose && wlsize < _worklist.size()) {
941 tty->print(" Push {");
942 while (wlsize != _worklist.size()) {
943 Node* pushed = _worklist.at(wlsize++);
944 tty->print(" %d", pushed->_idx);
945 }
946 tty->print_cr(" }");
947 }
948 }
949 if( VerifyIterativeGVN && nn != n ) {
950 verify_step((Node*) NULL); // ignore n, it might be subsumed
951 }
952 #endif
953 } else if (!n->is_top()) {
954 remove_dead_node(n);
955 }
956 }
958 #ifndef PRODUCT
959 C->verify_graph_edges();
960 if( VerifyOpto && allow_progress() ) {
961 // Must turn off allow_progress to enable assert and break recursion
962 C->root()->verify();
963 { // Check if any progress was missed using IterGVN
964 // Def-Use info enables transformations not attempted in wash-pass
965 // e.g. Region/Phi cleanup, ...
966 // Null-check elision -- may not have reached fixpoint
967 // do not propagate to dominated nodes
968 ResourceMark rm;
969 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
970 // Fill worklist completely
971 igvn2.init_worklist(C->root());
973 igvn2.set_allow_progress(false);
974 igvn2.optimize();
975 igvn2.set_allow_progress(true);
976 }
977 }
978 if ( VerifyIterativeGVN && PrintOpto ) {
979 if ( _verify_counter == _verify_full_passes )
980 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
981 _verify_full_passes);
982 else
983 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
984 _verify_counter, _verify_full_passes);
985 }
986 #endif
987 }
990 //------------------register_new_node_with_optimizer---------------------------
991 // Register a new node with the optimizer. Update the types array, the def-use
992 // info. Put on worklist.
993 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
994 set_type_bottom(n);
995 _worklist.push(n);
996 if (orig != NULL) C->copy_node_notes_to(n, orig);
997 return n;
998 }
1000 //------------------------------transform--------------------------------------
1001 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
1002 Node *PhaseIterGVN::transform( Node *n ) {
1003 if (_delay_transform) {
1004 // Register the node but don't optimize for now
1005 register_new_node_with_optimizer(n);
1006 return n;
1007 }
1009 // If brand new node, make space in type array, and give it a type.
1010 ensure_type_or_null(n);
1011 if (type_or_null(n) == NULL) {
1012 set_type_bottom(n);
1013 }
1015 return transform_old(n);
1016 }
1018 //------------------------------transform_old----------------------------------
1019 Node *PhaseIterGVN::transform_old( Node *n ) {
1020 #ifndef PRODUCT
1021 debug_only(uint loop_count = 0;);
1022 set_transforms();
1023 #endif
1024 // Remove 'n' from hash table in case it gets modified
1025 _table.hash_delete(n);
1026 if( VerifyIterativeGVN ) {
1027 assert( !_table.find_index(n->_idx), "found duplicate entry in table");
1028 }
1030 // Apply the Ideal call in a loop until it no longer applies
1031 Node *k = n;
1032 DEBUG_ONLY(dead_loop_check(k);)
1033 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1034 Node *i = k->Ideal(this, /*can_reshape=*/true);
1035 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1036 #ifndef PRODUCT
1037 if( VerifyIterativeGVN )
1038 verify_step(k);
1039 if( i && VerifyOpto ) {
1040 if( !allow_progress() ) {
1041 if (i->is_Add() && i->outcnt() == 1) {
1042 // Switched input to left side because this is the only use
1043 } else if( i->is_If() && (i->in(0) == NULL) ) {
1044 // This IF is dead because it is dominated by an equivalent IF When
1045 // dominating if changed, info is not propagated sparsely to 'this'
1046 // Propagating this info further will spuriously identify other
1047 // progress.
1048 return i;
1049 } else
1050 set_progress();
1051 } else
1052 set_progress();
1053 }
1054 #endif
1056 while( i ) {
1057 #ifndef PRODUCT
1058 debug_only( if( loop_count >= K ) i->dump(4); )
1059 assert(loop_count < K, "infinite loop in PhaseIterGVN::transform");
1060 debug_only( loop_count++; )
1061 #endif
1062 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1063 // Made a change; put users of original Node on worklist
1064 add_users_to_worklist( k );
1065 // Replacing root of transform tree?
1066 if( k != i ) {
1067 // Make users of old Node now use new.
1068 subsume_node( k, i );
1069 k = i;
1070 }
1071 DEBUG_ONLY(dead_loop_check(k);)
1072 // Try idealizing again
1073 DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1074 i = k->Ideal(this, /*can_reshape=*/true);
1075 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1076 #ifndef PRODUCT
1077 if( VerifyIterativeGVN )
1078 verify_step(k);
1079 if( i && VerifyOpto ) set_progress();
1080 #endif
1081 }
1083 // If brand new node, make space in type array.
1084 ensure_type_or_null(k);
1086 // See what kind of values 'k' takes on at runtime
1087 const Type *t = k->Value(this);
1088 assert(t != NULL, "value sanity");
1090 // Since I just called 'Value' to compute the set of run-time values
1091 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1092 // cache Value. Later requests for the local phase->type of this Node can
1093 // use the cached Value instead of suffering with 'bottom_type'.
1094 if (t != type_or_null(k)) {
1095 NOT_PRODUCT( set_progress(); )
1096 NOT_PRODUCT( inc_new_values();)
1097 set_type(k, t);
1098 // If k is a TypeNode, capture any more-precise type permanently into Node
1099 k->raise_bottom_type(t);
1100 // Move users of node to worklist
1101 add_users_to_worklist( k );
1102 }
1104 // If 'k' computes a constant, replace it with a constant
1105 if( t->singleton() && !k->is_Con() ) {
1106 NOT_PRODUCT( set_progress(); )
1107 Node *con = makecon(t); // Make a constant
1108 add_users_to_worklist( k );
1109 subsume_node( k, con ); // Everybody using k now uses con
1110 return con;
1111 }
1113 // Now check for Identities
1114 i = k->Identity(this); // Look for a nearby replacement
1115 if( i != k ) { // Found? Return replacement!
1116 NOT_PRODUCT( set_progress(); )
1117 add_users_to_worklist( k );
1118 subsume_node( k, i ); // Everybody using k now uses i
1119 return i;
1120 }
1122 // Global Value Numbering
1123 i = hash_find_insert(k); // Check for pre-existing node
1124 if( i && (i != k) ) {
1125 // Return the pre-existing node if it isn't dead
1126 NOT_PRODUCT( set_progress(); )
1127 add_users_to_worklist( k );
1128 subsume_node( k, i ); // Everybody using k now uses i
1129 return i;
1130 }
1132 // Return Idealized original
1133 return k;
1134 }
1136 //---------------------------------saturate------------------------------------
1137 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1138 const Type* limit_type) const {
1139 return new_type->narrow(old_type);
1140 }
1142 //------------------------------remove_globally_dead_node----------------------
1143 // Kill a globally dead Node. All uses are also globally dead and are
1144 // aggressively trimmed.
1145 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1146 enum DeleteProgress {
1147 PROCESS_INPUTS,
1148 PROCESS_OUTPUTS
1149 };
1150 assert(_stack.is_empty(), "not empty");
1151 _stack.push(dead, PROCESS_INPUTS);
1153 while (_stack.is_nonempty()) {
1154 dead = _stack.node();
1155 uint progress_state = _stack.index();
1156 assert(dead != C->root(), "killing root, eh?");
1157 assert(!dead->is_top(), "add check for top when pushing");
1158 NOT_PRODUCT( set_progress(); )
1159 if (progress_state == PROCESS_INPUTS) {
1160 // After following inputs, continue to outputs
1161 _stack.set_index(PROCESS_OUTPUTS);
1162 // Remove from iterative worklist
1163 _worklist.remove(dead);
1164 if (!dead->is_Con()) { // Don't kill cons but uses
1165 bool recurse = false;
1166 // Remove from hash table
1167 _table.hash_delete( dead );
1168 // Smash all inputs to 'dead', isolating him completely
1169 for( uint i = 0; i < dead->req(); i++ ) {
1170 Node *in = dead->in(i);
1171 if( in ) { // Points to something?
1172 dead->set_req(i,NULL); // Kill the edge
1173 if (in->outcnt() == 0 && in != C->top()) {// Made input go dead?
1174 _stack.push(in, PROCESS_INPUTS); // Recursively remove
1175 recurse = true;
1176 } else if (in->outcnt() == 1 &&
1177 in->has_special_unique_user()) {
1178 _worklist.push(in->unique_out());
1179 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1180 if( in->Opcode() == Op_Region )
1181 _worklist.push(in);
1182 else if( in->is_Store() ) {
1183 DUIterator_Fast imax, i = in->fast_outs(imax);
1184 _worklist.push(in->fast_out(i));
1185 i++;
1186 if(in->outcnt() == 2) {
1187 _worklist.push(in->fast_out(i));
1188 i++;
1189 }
1190 assert(!(i < imax), "sanity");
1191 }
1192 }
1193 }
1194 }
1195 C->record_dead_node(dead->_idx);
1196 if (dead->is_macro()) {
1197 C->remove_macro_node(dead);
1198 }
1200 if (recurse) {
1201 continue;
1202 }
1203 }
1204 // Constant node that has no out-edges and has only one in-edge from
1205 // root is usually dead. However, sometimes reshaping walk makes
1206 // it reachable by adding use edges. So, we will NOT count Con nodes
1207 // as dead to be conservative about the dead node count at any
1208 // given time.
1209 }
1211 // Aggressively kill globally dead uses
1212 // (Rather than pushing all the outs at once, we push one at a time,
1213 // plus the parent to resume later, because of the indefinite number
1214 // of edge deletions per loop trip.)
1215 if (dead->outcnt() > 0) {
1216 // Recursively remove
1217 _stack.push(dead->raw_out(0), PROCESS_INPUTS);
1218 } else {
1219 _stack.pop();
1220 }
1221 }
1222 }
1224 //------------------------------subsume_node-----------------------------------
1225 // Remove users from node 'old' and add them to node 'nn'.
1226 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1227 assert( old != hash_find(old), "should already been removed" );
1228 assert( old != C->top(), "cannot subsume top node");
1229 // Copy debug or profile information to the new version:
1230 C->copy_node_notes_to(nn, old);
1231 // Move users of node 'old' to node 'nn'
1232 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1233 Node* use = old->last_out(i); // for each use...
1234 // use might need re-hashing (but it won't if it's a new node)
1235 bool is_in_table = _table.hash_delete( use );
1236 // Update use-def info as well
1237 // We remove all occurrences of old within use->in,
1238 // so as to avoid rehashing any node more than once.
1239 // The hash table probe swamps any outer loop overhead.
1240 uint num_edges = 0;
1241 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1242 if (use->in(j) == old) {
1243 use->set_req(j, nn);
1244 ++num_edges;
1245 }
1246 }
1247 // Insert into GVN hash table if unique
1248 // If a duplicate, 'use' will be cleaned up when pulled off worklist
1249 if( is_in_table ) {
1250 hash_find_insert(use);
1251 }
1252 i -= num_edges; // we deleted 1 or more copies of this edge
1253 }
1255 // Smash all inputs to 'old', isolating him completely
1256 Node *temp = new (C) Node(1);
1257 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1258 remove_dead_node( old );
1259 temp->del_req(0); // Yank bogus edge
1260 #ifndef PRODUCT
1261 if( VerifyIterativeGVN ) {
1262 for ( int i = 0; i < _verify_window_size; i++ ) {
1263 if ( _verify_window[i] == old )
1264 _verify_window[i] = nn;
1265 }
1266 }
1267 #endif
1268 _worklist.remove(temp); // this can be necessary
1269 temp->destruct(); // reuse the _idx of this little guy
1270 }
1272 //------------------------------add_users_to_worklist--------------------------
1273 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1274 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1275 _worklist.push(n->fast_out(i)); // Push on worklist
1276 }
1277 }
1279 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1280 add_users_to_worklist0(n);
1282 // Move users of node to worklist
1283 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1284 Node* use = n->fast_out(i); // Get use
1286 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1287 use->is_Store() ) // Enable store/load same address
1288 add_users_to_worklist0(use);
1290 // If we changed the receiver type to a call, we need to revisit
1291 // the Catch following the call. It's looking for a non-NULL
1292 // receiver to know when to enable the regular fall-through path
1293 // in addition to the NullPtrException path.
1294 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1295 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control);
1296 if (p != NULL) {
1297 add_users_to_worklist0(p);
1298 }
1299 }
1301 if( use->is_Cmp() ) { // Enable CMP/BOOL optimization
1302 add_users_to_worklist(use); // Put Bool on worklist
1303 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1304 // phi merging either 0 or 1 onto the worklist
1305 if (use->outcnt() > 0) {
1306 Node* bol = use->raw_out(0);
1307 if (bol->outcnt() > 0) {
1308 Node* iff = bol->raw_out(0);
1309 if (iff->outcnt() == 2) {
1310 Node* ifproj0 = iff->raw_out(0);
1311 Node* ifproj1 = iff->raw_out(1);
1312 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1313 Node* region0 = ifproj0->raw_out(0);
1314 Node* region1 = ifproj1->raw_out(0);
1315 if( region0 == region1 )
1316 add_users_to_worklist0(region0);
1317 }
1318 }
1319 }
1320 }
1321 }
1323 uint use_op = use->Opcode();
1324 // If changed Cast input, check Phi users for simple cycles
1325 if( use->is_ConstraintCast() || use->is_CheckCastPP() ) {
1326 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1327 Node* u = use->fast_out(i2);
1328 if (u->is_Phi())
1329 _worklist.push(u);
1330 }
1331 }
1332 // If changed LShift inputs, check RShift users for useless sign-ext
1333 if( use_op == Op_LShiftI ) {
1334 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1335 Node* u = use->fast_out(i2);
1336 if (u->Opcode() == Op_RShiftI)
1337 _worklist.push(u);
1338 }
1339 }
1340 // If changed AddP inputs, check Stores for loop invariant
1341 if( use_op == Op_AddP ) {
1342 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1343 Node* u = use->fast_out(i2);
1344 if (u->is_Mem())
1345 _worklist.push(u);
1346 }
1347 }
1348 // If changed initialization activity, check dependent Stores
1349 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1350 InitializeNode* init = use->as_Allocate()->initialization();
1351 if (init != NULL) {
1352 Node* imem = init->proj_out(TypeFunc::Memory);
1353 if (imem != NULL) add_users_to_worklist0(imem);
1354 }
1355 }
1356 if (use_op == Op_Initialize) {
1357 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory);
1358 if (imem != NULL) add_users_to_worklist0(imem);
1359 }
1360 }
1361 }
1363 //=============================================================================
1364 #ifndef PRODUCT
1365 uint PhaseCCP::_total_invokes = 0;
1366 uint PhaseCCP::_total_constants = 0;
1367 #endif
1368 //------------------------------PhaseCCP---------------------------------------
1369 // Conditional Constant Propagation, ala Wegman & Zadeck
1370 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1371 NOT_PRODUCT( clear_constants(); )
1372 assert( _worklist.size() == 0, "" );
1373 // Clear out _nodes from IterGVN. Must be clear to transform call.
1374 _nodes.clear(); // Clear out from IterGVN
1375 analyze();
1376 }
1378 #ifndef PRODUCT
1379 //------------------------------~PhaseCCP--------------------------------------
1380 PhaseCCP::~PhaseCCP() {
1381 inc_invokes();
1382 _total_constants += count_constants();
1383 }
1384 #endif
1387 #ifdef ASSERT
1388 static bool ccp_type_widens(const Type* t, const Type* t0) {
1389 assert(t->meet(t0) == t, "Not monotonic");
1390 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1391 case Type::Int:
1392 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1393 break;
1394 case Type::Long:
1395 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1396 break;
1397 }
1398 return true;
1399 }
1400 #endif //ASSERT
1402 //------------------------------analyze----------------------------------------
1403 void PhaseCCP::analyze() {
1404 // Initialize all types to TOP, optimistic analysis
1405 for (int i = C->unique() - 1; i >= 0; i--) {
1406 _types.map(i,Type::TOP);
1407 }
1409 // Push root onto worklist
1410 Unique_Node_List worklist;
1411 worklist.push(C->root());
1413 // Pull from worklist; compute new value; push changes out.
1414 // This loop is the meat of CCP.
1415 while( worklist.size() ) {
1416 Node *n = worklist.pop();
1417 const Type *t = n->Value(this);
1418 if (t != type(n)) {
1419 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1420 #ifndef PRODUCT
1421 if( TracePhaseCCP ) {
1422 t->dump();
1423 do { tty->print("\t"); } while (tty->position() < 16);
1424 n->dump();
1425 }
1426 #endif
1427 set_type(n, t);
1428 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1429 Node* m = n->fast_out(i); // Get user
1430 if( m->is_Region() ) { // New path to Region? Must recheck Phis too
1431 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1432 Node* p = m->fast_out(i2); // Propagate changes to uses
1433 if( p->bottom_type() != type(p) ) // If not already bottomed out
1434 worklist.push(p); // Propagate change to user
1435 }
1436 }
1437 // If we changed the receiver type to a call, we need to revisit
1438 // the Catch following the call. It's looking for a non-NULL
1439 // receiver to know when to enable the regular fall-through path
1440 // in addition to the NullPtrException path
1441 if (m->is_Call()) {
1442 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1443 Node* p = m->fast_out(i2); // Propagate changes to uses
1444 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1)
1445 worklist.push(p->unique_out());
1446 }
1447 }
1448 if( m->bottom_type() != type(m) ) // If not already bottomed out
1449 worklist.push(m); // Propagate change to user
1450 }
1451 }
1452 }
1453 }
1455 //------------------------------do_transform-----------------------------------
1456 // Top level driver for the recursive transformer
1457 void PhaseCCP::do_transform() {
1458 // Correct leaves of new-space Nodes; they point to old-space.
1459 C->set_root( transform(C->root())->as_Root() );
1460 assert( C->top(), "missing TOP node" );
1461 assert( C->root(), "missing root" );
1462 }
1464 //------------------------------transform--------------------------------------
1465 // Given a Node in old-space, clone him into new-space.
1466 // Convert any of his old-space children into new-space children.
1467 Node *PhaseCCP::transform( Node *n ) {
1468 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1469 if( new_node != NULL )
1470 return new_node; // Been there, done that, return old answer
1471 new_node = transform_once(n); // Check for constant
1472 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1474 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1475 GrowableArray <Node *> trstack(C->unique() >> 1);
1477 trstack.push(new_node); // Process children of cloned node
1478 while ( trstack.is_nonempty() ) {
1479 Node *clone = trstack.pop();
1480 uint cnt = clone->req();
1481 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1482 Node *input = clone->in(i);
1483 if( input != NULL ) { // Ignore NULLs
1484 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1485 if( new_input == NULL ) {
1486 new_input = transform_once(input); // Check for constant
1487 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1488 trstack.push(new_input);
1489 }
1490 assert( new_input == clone->in(i), "insanity check");
1491 }
1492 }
1493 }
1494 return new_node;
1495 }
1498 //------------------------------transform_once---------------------------------
1499 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1500 Node *PhaseCCP::transform_once( Node *n ) {
1501 const Type *t = type(n);
1502 // Constant? Use constant Node instead
1503 if( t->singleton() ) {
1504 Node *nn = n; // Default is to return the original constant
1505 if( t == Type::TOP ) {
1506 // cache my top node on the Compile instance
1507 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1508 C->set_cached_top_node( ConNode::make(C, Type::TOP) );
1509 set_type(C->top(), Type::TOP);
1510 }
1511 nn = C->top();
1512 }
1513 if( !n->is_Con() ) {
1514 if( t != Type::TOP ) {
1515 nn = makecon(t); // ConNode::make(t);
1516 NOT_PRODUCT( inc_constants(); )
1517 } else if( n->is_Region() ) { // Unreachable region
1518 // Note: nn == C->top()
1519 n->set_req(0, NULL); // Cut selfreference
1520 // Eagerly remove dead phis to avoid phis copies creation.
1521 for (DUIterator i = n->outs(); n->has_out(i); i++) {
1522 Node* m = n->out(i);
1523 if( m->is_Phi() ) {
1524 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1525 replace_node(m, nn);
1526 --i; // deleted this phi; rescan starting with next position
1527 }
1528 }
1529 }
1530 replace_node(n,nn); // Update DefUse edges for new constant
1531 }
1532 return nn;
1533 }
1535 // If x is a TypeNode, capture any more-precise type permanently into Node
1536 if (t != n->bottom_type()) {
1537 hash_delete(n); // changing bottom type may force a rehash
1538 n->raise_bottom_type(t);
1539 _worklist.push(n); // n re-enters the hash table via the worklist
1540 }
1542 // Idealize graph using DU info. Must clone() into new-space.
1543 // DU info is generally used to show profitability, progress or safety
1544 // (but generally not needed for correctness).
1545 Node *nn = n->Ideal_DU_postCCP(this);
1547 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1548 switch( n->Opcode() ) {
1549 case Op_FastLock: // Revisit FastLocks for lock coarsening
1550 case Op_If:
1551 case Op_CountedLoopEnd:
1552 case Op_Region:
1553 case Op_Loop:
1554 case Op_CountedLoop:
1555 case Op_Conv2B:
1556 case Op_Opaque1:
1557 case Op_Opaque2:
1558 _worklist.push(n);
1559 break;
1560 default:
1561 break;
1562 }
1563 if( nn ) {
1564 _worklist.push(n);
1565 // Put users of 'n' onto worklist for second igvn transform
1566 add_users_to_worklist(n);
1567 return nn;
1568 }
1570 return n;
1571 }
1573 //---------------------------------saturate------------------------------------
1574 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
1575 const Type* limit_type) const {
1576 const Type* wide_type = new_type->widen(old_type, limit_type);
1577 if (wide_type != new_type) { // did we widen?
1578 // If so, we may have widened beyond the limit type. Clip it back down.
1579 new_type = wide_type->filter(limit_type);
1580 }
1581 return new_type;
1582 }
1584 //------------------------------print_statistics-------------------------------
1585 #ifndef PRODUCT
1586 void PhaseCCP::print_statistics() {
1587 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
1588 }
1589 #endif
1592 //=============================================================================
1593 #ifndef PRODUCT
1594 uint PhasePeephole::_total_peepholes = 0;
1595 #endif
1596 //------------------------------PhasePeephole----------------------------------
1597 // Conditional Constant Propagation, ala Wegman & Zadeck
1598 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
1599 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
1600 NOT_PRODUCT( clear_peepholes(); )
1601 }
1603 #ifndef PRODUCT
1604 //------------------------------~PhasePeephole---------------------------------
1605 PhasePeephole::~PhasePeephole() {
1606 _total_peepholes += count_peepholes();
1607 }
1608 #endif
1610 //------------------------------transform--------------------------------------
1611 Node *PhasePeephole::transform( Node *n ) {
1612 ShouldNotCallThis();
1613 return NULL;
1614 }
1616 //------------------------------do_transform-----------------------------------
1617 void PhasePeephole::do_transform() {
1618 bool method_name_not_printed = true;
1620 // Examine each basic block
1621 for( uint block_number = 1; block_number < _cfg._num_blocks; ++block_number ) {
1622 Block *block = _cfg._blocks[block_number];
1623 bool block_not_printed = true;
1625 // and each instruction within a block
1626 uint end_index = block->_nodes.size();
1627 // block->end_idx() not valid after PhaseRegAlloc
1628 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
1629 Node *n = block->_nodes.at(instruction_index);
1630 if( n->is_Mach() ) {
1631 MachNode *m = n->as_Mach();
1632 int deleted_count = 0;
1633 // check for peephole opportunities
1634 MachNode *m2 = m->peephole( block, instruction_index, _regalloc, deleted_count, C );
1635 if( m2 != NULL ) {
1636 #ifndef PRODUCT
1637 if( PrintOptoPeephole ) {
1638 // Print method, first time only
1639 if( C->method() && method_name_not_printed ) {
1640 C->method()->print_short_name(); tty->cr();
1641 method_name_not_printed = false;
1642 }
1643 // Print this block
1644 if( Verbose && block_not_printed) {
1645 tty->print_cr("in block");
1646 block->dump();
1647 block_not_printed = false;
1648 }
1649 // Print instructions being deleted
1650 for( int i = (deleted_count - 1); i >= 0; --i ) {
1651 block->_nodes.at(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
1652 }
1653 tty->print_cr("replaced with");
1654 // Print new instruction
1655 m2->format(_regalloc);
1656 tty->print("\n\n");
1657 }
1658 #endif
1659 // Remove old nodes from basic block and update instruction_index
1660 // (old nodes still exist and may have edges pointing to them
1661 // as register allocation info is stored in the allocator using
1662 // the node index to live range mappings.)
1663 uint safe_instruction_index = (instruction_index - deleted_count);
1664 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
1665 block->_nodes.remove( instruction_index );
1666 }
1667 // install new node after safe_instruction_index
1668 block->_nodes.insert( safe_instruction_index + 1, m2 );
1669 end_index = block->_nodes.size() - 1; // Recompute new block size
1670 NOT_PRODUCT( inc_peepholes(); )
1671 }
1672 }
1673 }
1674 }
1675 }
1677 //------------------------------print_statistics-------------------------------
1678 #ifndef PRODUCT
1679 void PhasePeephole::print_statistics() {
1680 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
1681 }
1682 #endif
1685 //=============================================================================
1686 //------------------------------set_req_X--------------------------------------
1687 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
1688 assert( is_not_dead(n), "can not use dead node");
1689 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
1690 Node *old = in(i);
1691 set_req(i, n);
1693 // old goes dead?
1694 if( old ) {
1695 switch (old->outcnt()) {
1696 case 0:
1697 // Put into the worklist to kill later. We do not kill it now because the
1698 // recursive kill will delete the current node (this) if dead-loop exists
1699 if (!old->is_top())
1700 igvn->_worklist.push( old );
1701 break;
1702 case 1:
1703 if( old->is_Store() || old->has_special_unique_user() )
1704 igvn->add_users_to_worklist( old );
1705 break;
1706 case 2:
1707 if( old->is_Store() )
1708 igvn->add_users_to_worklist( old );
1709 if( old->Opcode() == Op_Region )
1710 igvn->_worklist.push(old);
1711 break;
1712 case 3:
1713 if( old->Opcode() == Op_Region ) {
1714 igvn->_worklist.push(old);
1715 igvn->add_users_to_worklist( old );
1716 }
1717 break;
1718 default:
1719 break;
1720 }
1721 }
1723 }
1725 //-------------------------------replace_by-----------------------------------
1726 // Using def-use info, replace one node for another. Follow the def-use info
1727 // to all users of the OLD node. Then make all uses point to the NEW node.
1728 void Node::replace_by(Node *new_node) {
1729 assert(!is_top(), "top node has no DU info");
1730 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
1731 Node* use = last_out(i);
1732 uint uses_found = 0;
1733 for (uint j = 0; j < use->len(); j++) {
1734 if (use->in(j) == this) {
1735 if (j < use->req())
1736 use->set_req(j, new_node);
1737 else use->set_prec(j, new_node);
1738 uses_found++;
1739 }
1740 }
1741 i -= uses_found; // we deleted 1 or more copies of this edge
1742 }
1743 }
1745 //=============================================================================
1746 //-----------------------------------------------------------------------------
1747 void Type_Array::grow( uint i ) {
1748 if( !_max ) {
1749 _max = 1;
1750 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
1751 _types[0] = NULL;
1752 }
1753 uint old = _max;
1754 while( i >= _max ) _max <<= 1; // Double to fit
1755 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
1756 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
1757 }
1759 //------------------------------dump-------------------------------------------
1760 #ifndef PRODUCT
1761 void Type_Array::dump() const {
1762 uint max = Size();
1763 for( uint i = 0; i < max; i++ ) {
1764 if( _types[i] != NULL ) {
1765 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
1766 }
1767 }
1768 }
1769 #endif
