1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)cfgnode.cpp 1.262 08/11/24 12:22:57 JVM"
3 #endif
4 /*
5 * Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 // Portions of code courtesy of Clifford Click
29
30 // Optimization - Graph Style
31
32 #include "incls/_precompiled.incl"
33 #include "incls/_cfgnode.cpp.incl"
34
35 //=============================================================================
36 //------------------------------Value------------------------------------------
37 // Compute the type of the RegionNode.
38 const Type *RegionNode::Value( PhaseTransform *phase ) const {
39 for( uint i=1; i<req(); ++i ) { // For all paths in
40 Node *n = in(i); // Get Control source
41 if( !n ) continue; // Missing inputs are TOP
42 if( phase->type(n) == Type::CONTROL )
43 return Type::CONTROL;
44 }
45 return Type::TOP; // All paths dead? Then so are we
46 }
47
48 //------------------------------Identity---------------------------------------
49 // Check for Region being Identity.
50 Node *RegionNode::Identity( PhaseTransform *phase ) {
51 // Cannot have Region be an identity, even if it has only 1 input.
52 // Phi users cannot have their Region input folded away for them,
53 // since they need to select the proper data input
54 return this;
55 }
56
57 //------------------------------merge_region-----------------------------------
58 // If a Region flows into a Region, merge into one big happy merge. This is
59 // hard to do if there is stuff that has to happen
60 static Node *merge_region(RegionNode *region, PhaseGVN *phase) {
61 if( region->Opcode() != Op_Region ) // Do not do to LoopNodes
62 return NULL;
63 Node *progress = NULL; // Progress flag
64 PhaseIterGVN *igvn = phase->is_IterGVN();
65
66 uint rreq = region->req();
67 for( uint i = 1; i < rreq; i++ ) {
68 Node *r = region->in(i);
69 if( r && r->Opcode() == Op_Region && // Found a region?
70 r->in(0) == r && // Not already collapsed?
71 r != region && // Avoid stupid situations
72 r->outcnt() == 2 ) { // Self user and 'region' user only?
73 assert(!r->as_Region()->has_phi(), "no phi users");
74 if( !progress ) { // No progress
75 if (region->has_phi()) {
76 return NULL; // Only flatten if no Phi users
77 // igvn->hash_delete( phi );
78 }
79 igvn->hash_delete( region );
80 progress = region; // Making progress
81 }
82 igvn->hash_delete( r );
83
84 // Append inputs to 'r' onto 'region'
85 for( uint j = 1; j < r->req(); j++ ) {
86 // Move an input from 'r' to 'region'
87 region->add_req(r->in(j));
88 r->set_req(j, phase->C->top());
89 // Update phis of 'region'
90 //for( uint k = 0; k < max; k++ ) {
91 // Node *phi = region->out(k);
92 // if( phi->is_Phi() ) {
93 // phi->add_req(phi->in(i));
94 // }
95 //}
96
97 rreq++; // One more input to Region
98 } // Found a region to merge into Region
99 // Clobber pointer to the now dead 'r'
100 region->set_req(i, phase->C->top());
101 }
102 }
103
104 return progress;
105 }
106
107
108
109 //--------------------------------has_phi--------------------------------------
110 // Helper function: Return any PhiNode that uses this region or NULL
111 PhiNode* RegionNode::has_phi() const {
112 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
113 Node* phi = fast_out(i);
114 if (phi->is_Phi()) { // Check for Phi users
115 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)");
116 return phi->as_Phi(); // this one is good enough
117 }
118 }
119
120 return NULL;
121 }
122
123
124 //-----------------------------has_unique_phi----------------------------------
125 // Helper function: Return the only PhiNode that uses this region or NULL
126 PhiNode* RegionNode::has_unique_phi() const {
127 // Check that only one use is a Phi
128 PhiNode* only_phi = NULL;
129 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
130 Node* phi = fast_out(i);
131 if (phi->is_Phi()) { // Check for Phi users
132 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)");
133 if (only_phi == NULL) {
134 only_phi = phi->as_Phi();
135 } else {
136 return NULL; // multiple phis
137 }
138 }
139 }
140
141 return only_phi;
142 }
143
144
145 //------------------------------check_phi_clipping-----------------------------
146 // Helper function for RegionNode's identification of FP clipping
147 // Check inputs to the Phi
148 static bool check_phi_clipping( PhiNode *phi, ConNode * &min, uint &min_idx, ConNode * &max, uint &max_idx, Node * &val, uint &val_idx ) {
149 min = NULL;
150 max = NULL;
151 val = NULL;
152 min_idx = 0;
153 max_idx = 0;
154 val_idx = 0;
155 uint phi_max = phi->req();
156 if( phi_max == 4 ) {
157 for( uint j = 1; j < phi_max; ++j ) {
158 Node *n = phi->in(j);
159 int opcode = n->Opcode();
160 switch( opcode ) {
161 case Op_ConI:
162 {
163 if( min == NULL ) {
164 min = n->Opcode() == Op_ConI ? (ConNode*)n : NULL;
165 min_idx = j;
166 } else {
167 max = n->Opcode() == Op_ConI ? (ConNode*)n : NULL;
168 max_idx = j;
169 if( min->get_int() > max->get_int() ) {
170 // Swap min and max
171 ConNode *temp;
172 uint temp_idx;
173 temp = min; min = max; max = temp;
174 temp_idx = min_idx; min_idx = max_idx; max_idx = temp_idx;
175 }
176 }
177 }
178 break;
179 default:
180 {
181 val = n;
182 val_idx = j;
183 }
184 break;
185 }
186 }
187 }
188 return ( min && max && val && (min->get_int() <= 0) && (max->get_int() >=0) );
189 }
190
191
192 //------------------------------check_if_clipping------------------------------
193 // Helper function for RegionNode's identification of FP clipping
194 // Check that inputs to Region come from two IfNodes,
195 //
196 // If
197 // False True
198 // If |
199 // False True |
200 // | | |
201 // RegionNode_inputs
202 //
203 static bool check_if_clipping( const RegionNode *region, IfNode * &bot_if, IfNode * &top_if ) {
204 top_if = NULL;
205 bot_if = NULL;
206
207 // Check control structure above RegionNode for (if ( if ) )
208 Node *in1 = region->in(1);
209 Node *in2 = region->in(2);
210 Node *in3 = region->in(3);
211 // Check that all inputs are projections
212 if( in1->is_Proj() && in2->is_Proj() && in3->is_Proj() ) {
213 Node *in10 = in1->in(0);
214 Node *in20 = in2->in(0);
215 Node *in30 = in3->in(0);
216 // Check that #1 and #2 are ifTrue and ifFalse from same If
217 if( in10 != NULL && in10->is_If() &&
218 in20 != NULL && in20->is_If() &&
219 in30 != NULL && in30->is_If() && in10 == in20 &&
220 (in1->Opcode() != in2->Opcode()) ) {
221 Node *in100 = in10->in(0);
222 Node *in1000 = (in100 != NULL && in100->is_Proj()) ? in100->in(0) : NULL;
223 // Check that control for in10 comes from other branch of IF from in3
224 if( in1000 != NULL && in1000->is_If() &&
225 in30 == in1000 && (in3->Opcode() != in100->Opcode()) ) {
226 // Control pattern checks
227 top_if = (IfNode*)in1000;
228 bot_if = (IfNode*)in10;
229 }
230 }
231 }
232
233 return (top_if != NULL);
234 }
235
236
237 //------------------------------check_convf2i_clipping-------------------------
238 // Helper function for RegionNode's identification of FP clipping
239 // Verify that the value input to the phi comes from "ConvF2I; LShift; RShift"
240 static bool check_convf2i_clipping( PhiNode *phi, uint idx, ConvF2INode * &convf2i, Node *min, Node *max) {
241 convf2i = NULL;
242
243 // Check for the RShiftNode
244 Node *rshift = phi->in(idx);
245 assert( rshift, "Previous checks ensure phi input is present");
246 if( rshift->Opcode() != Op_RShiftI ) { return false; }
247
248 // Check for the LShiftNode
249 Node *lshift = rshift->in(1);
250 assert( lshift, "Previous checks ensure phi input is present");
251 if( lshift->Opcode() != Op_LShiftI ) { return false; }
252
253 // Check for the ConvF2INode
254 Node *conv = lshift->in(1);
255 if( conv->Opcode() != Op_ConvF2I ) { return false; }
256
257 // Check that shift amounts are only to get sign bits set after F2I
258 jint max_cutoff = max->get_int();
259 jint min_cutoff = min->get_int();
260 jint left_shift = lshift->in(2)->get_int();
261 jint right_shift = rshift->in(2)->get_int();
262 jint max_post_shift = nth_bit(BitsPerJavaInteger - left_shift - 1);
263 if( left_shift != right_shift ||
264 0 > left_shift || left_shift >= BitsPerJavaInteger ||
265 max_post_shift < max_cutoff ||
266 max_post_shift < -min_cutoff ) {
267 // Shifts are necessary but current transformation eliminates them
268 return false;
269 }
270
271 // OK to return the result of ConvF2I without shifting
272 convf2i = (ConvF2INode*)conv;
273 return true;
274 }
275
276
277 //------------------------------check_compare_clipping-------------------------
278 // Helper function for RegionNode's identification of FP clipping
279 static bool check_compare_clipping( bool less_than, IfNode *iff, ConNode *limit, Node * & input ) {
280 Node *i1 = iff->in(1);
281 if ( !i1->is_Bool() ) { return false; }
282 BoolNode *bool1 = i1->as_Bool();
283 if( less_than && bool1->_test._test != BoolTest::le ) { return false; }
284 else if( !less_than && bool1->_test._test != BoolTest::lt ) { return false; }
285 const Node *cmpF = bool1->in(1);
286 if( cmpF->Opcode() != Op_CmpF ) { return false; }
287 // Test that the float value being compared against
288 // is equivalent to the int value used as a limit
289 Node *nodef = cmpF->in(2);
290 if( nodef->Opcode() != Op_ConF ) { return false; }
291 jfloat conf = nodef->getf();
292 jint coni = limit->get_int();
293 if( ((int)conf) != coni ) { return false; }
294 input = cmpF->in(1);
295 return true;
296 }
297
298 //------------------------------is_unreachable_region--------------------------
299 // Find if the Region node is reachable from the root.
300 bool RegionNode::is_unreachable_region(PhaseGVN *phase) const {
301 assert(req() == 2, "");
302
303 // First, cut the simple case of fallthrough region when NONE of
304 // region's phis references itself directly or through a data node.
305 uint max = outcnt();
306 uint i;
307 for (i = 0; i < max; i++) {
308 Node* phi = raw_out(i);
309 if (phi != NULL && phi->is_Phi()) {
310 assert(phase->eqv(phi->in(0), this) && phi->req() == 2, "");
311 if (phi->outcnt() == 0)
312 continue; // Safe case - no loops
313 if (phi->outcnt() == 1) {
314 Node* u = phi->raw_out(0);
315 // Skip if only one use is an other Phi or Call or Uncommon trap.
316 // It is safe to consider this case as fallthrough.
317 if (u != NULL && (u->is_Phi() || u->is_CFG()))
318 continue;
319 }
320 // Check when phi references itself directly or through an other node.
321 if (phi->as_Phi()->simple_data_loop_check(phi->in(1)) >= PhiNode::Unsafe)
322 break; // Found possible unsafe data loop.
323 }
324 }
325 if (i >= max)
326 return false; // An unsafe case was NOT found - don't need graph walk.
327
328 // Unsafe case - check if the Region node is reachable from root.
329 ResourceMark rm;
330
331 Arena *a = Thread::current()->resource_area();
332 Node_List nstack(a);
333 VectorSet visited(a);
334
335 // Mark all control nodes reachable from root outputs
336 Node *n = (Node*)phase->C->root();
337 nstack.push(n);
338 visited.set(n->_idx);
339 while (nstack.size() != 0) {
340 n = nstack.pop();
341 uint max = n->outcnt();
342 for (uint i = 0; i < max; i++) {
343 Node* m = n->raw_out(i);
344 if (m != NULL && m->is_CFG()) {
345 if (phase->eqv(m, this)) {
346 return false; // We reached the Region node - it is not dead.
347 }
348 if (!visited.test_set(m->_idx))
349 nstack.push(m);
350 }
351 }
352 }
353
354 return true; // The Region node is unreachable - it is dead.
355 }
356
357 //------------------------------Ideal------------------------------------------
358 // Return a node which is more "ideal" than the current node. Must preserve
359 // the CFG, but we can still strip out dead paths.
360 Node *RegionNode::Ideal(PhaseGVN *phase, bool can_reshape) {
361 if( !can_reshape && !in(0) ) return NULL; // Already degraded to a Copy
362 assert(!in(0) || !in(0)->is_Root(), "not a specially hidden merge");
363
364 // Check for RegionNode with no Phi users and both inputs come from either
365 // arm of the same IF. If found, then the control-flow split is useless.
366 bool has_phis = false;
367 if (can_reshape) { // Need DU info to check for Phi users
368 has_phis = (has_phi() != NULL); // Cache result
369 if (!has_phis) { // No Phi users? Nothing merging?
370 for (uint i = 1; i < req()-1; i++) {
371 Node *if1 = in(i);
372 if( !if1 ) continue;
373 Node *iff = if1->in(0);
374 if( !iff || !iff->is_If() ) continue;
375 for( uint j=i+1; j<req(); j++ ) {
376 if( in(j) && in(j)->in(0) == iff &&
377 if1->Opcode() != in(j)->Opcode() ) {
378 // Add the IF Projections to the worklist. They (and the IF itself)
379 // will be eliminated if dead.
380 phase->is_IterGVN()->add_users_to_worklist(iff);
381 set_req(i, iff->in(0));// Skip around the useless IF diamond
382 set_req(j, NULL);
383 return this; // Record progress
384 }
385 }
386 }
387 }
388 }
389
390 // Remove TOP or NULL input paths. If only 1 input path remains, this Region
391 // degrades to a copy.
392 bool add_to_worklist = false;
393 int cnt = 0; // Count of values merging
394 DEBUG_ONLY( int cnt_orig = req(); ) // Save original inputs count
395 int del_it = 0; // The last input path we delete
396 // For all inputs...
397 for( uint i=1; i<req(); ++i ){// For all paths in
398 Node *n = in(i); // Get the input
399 if( n != NULL ) {
400 // Remove useless control copy inputs
401 if( n->is_Region() && n->as_Region()->is_copy() ) {
402 set_req(i, n->nonnull_req());
403 i--;
404 continue;
405 }
406 if( n->is_Proj() ) { // Remove useless rethrows
407 Node *call = n->in(0);
408 if (call->is_Call() && call->as_Call()->entry_point() == OptoRuntime::rethrow_stub()) {
409 set_req(i, call->in(0));
410 i--;
411 continue;
412 }
413 }
414 if( phase->type(n) == Type::TOP ) {
415 set_req(i, NULL); // Ignore TOP inputs
416 i--;
417 continue;
418 }
419 cnt++; // One more value merging
420
421 } else if (can_reshape) { // Else found dead path with DU info
422 PhaseIterGVN *igvn = phase->is_IterGVN();
423 del_req(i); // Yank path from self
424 del_it = i;
425 uint max = outcnt();
426 DUIterator j;
427 bool progress = true;
428 while(progress) { // Need to establish property over all users
429 progress = false;
430 for (j = outs(); has_out(j); j++) {
431 Node *n = out(j);
432 if( n->req() != req() && n->is_Phi() ) {
433 assert( n->in(0) == this, "" );
434 igvn->hash_delete(n); // Yank from hash before hacking edges
435 n->set_req_X(i,NULL,igvn);// Correct DU info
436 n->del_req(i); // Yank path from Phis
437 if( max != outcnt() ) {
438 progress = true;
439 j = refresh_out_pos(j);
440 max = outcnt();
441 }
442 }
443 }
444 }
445 add_to_worklist = true;
446 i--;
447 }
448 }
449
450 if (can_reshape && cnt == 1) {
451 // Is it dead loop?
452 // If it is LoopNopde it had 2 (+1 itself) inputs and
453 // one of them was cut. The loop is dead if it was EntryContol.
454 assert(!this->is_Loop() || cnt_orig == 3, "Loop node should have 3 inputs");
455 if (this->is_Loop() && del_it == LoopNode::EntryControl ||
456 !this->is_Loop() && has_phis && is_unreachable_region(phase)) {
457 // Yes, the region will be removed during the next step below.
458 // Cut the backedge input and remove phis since no data paths left.
459 // We don't cut outputs to other nodes here since we need to put them
460 // on the worklist.
461 del_req(1);
462 cnt = 0;
463 assert( req() == 1, "no more inputs expected" );
464 uint max = outcnt();
465 bool progress = true;
466 Node *top = phase->C->top();
467 PhaseIterGVN *igvn = phase->is_IterGVN();
468 DUIterator j;
469 while(progress) {
470 progress = false;
471 for (j = outs(); has_out(j); j++) {
472 Node *n = out(j);
473 if( n->is_Phi() ) {
474 assert( igvn->eqv(n->in(0), this), "" );
475 assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" );
476 // Break dead loop data path.
477 // Eagerly replace phis with top to avoid phis copies generation.
478 igvn->add_users_to_worklist(n);
479 igvn->hash_delete(n); // Yank from hash before hacking edges
480 igvn->subsume_node(n, top);
481 if( max != outcnt() ) {
482 progress = true;
483 j = refresh_out_pos(j);
484 max = outcnt();
485 }
486 }
487 }
488 }
489 add_to_worklist = true;
490 }
491 }
492 if (add_to_worklist) {
493 phase->is_IterGVN()->add_users_to_worklist(this); // Revisit collapsed Phis
494 }
495
496 if( cnt <= 1 ) { // Only 1 path in?
497 set_req(0, NULL); // Null control input for region copy
498 if( cnt == 0 && !can_reshape) { // Parse phase - leave the node as it is.
499 // No inputs or all inputs are NULL.
500 return NULL;
501 } else if (can_reshape) { // Optimization phase - remove the node
502 PhaseIterGVN *igvn = phase->is_IterGVN();
503 Node *parent_ctrl;
504 if( cnt == 0 ) {
505 assert( req() == 1, "no inputs expected" );
506 // During IGVN phase such region will be subsumed by TOP node
507 // so region's phis will have TOP as control node.
508 // Kill phis here to avoid it. PhiNode::is_copy() will be always false.
509 // Also set other user's input to top.
510 parent_ctrl = phase->C->top();
511 } else {
512 // The fallthrough case since we already checked dead loops above.
513 parent_ctrl = in(1);
514 assert(parent_ctrl != NULL, "Region is a copy of some non-null control");
515 assert(!igvn->eqv(parent_ctrl, this), "Close dead loop");
516 }
517 if (!add_to_worklist)
518 igvn->add_users_to_worklist(this); // Check for further allowed opts
519 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) {
520 Node* n = last_out(i);
521 igvn->hash_delete(n); // Remove from worklist before modifying edges
522 if( n->is_Phi() ) { // Collapse all Phis
523 // Eagerly replace phis to avoid copies generation.
524 igvn->add_users_to_worklist(n);
525 igvn->hash_delete(n); // Yank from hash before hacking edges
526 if( cnt == 0 ) {
527 assert( n->req() == 1, "No data inputs expected" );
528 igvn->subsume_node(n, parent_ctrl); // replaced by top
529 } else {
530 assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" );
531 Node* in1 = n->in(1); // replaced by unique input
532 if( n->as_Phi()->is_unsafe_data_reference(in1) )
533 in1 = phase->C->top(); // replaced by top
534 igvn->subsume_node(n, in1);
535 }
536 }
537 else if( n->is_Region() ) { // Update all incoming edges
538 assert( !igvn->eqv(n, this), "Must be removed from DefUse edges");
539 uint uses_found = 0;
540 for( uint k=1; k < n->req(); k++ ) {
541 if( n->in(k) == this ) {
542 n->set_req(k, parent_ctrl);
543 uses_found++;
544 }
545 }
546 if( uses_found > 1 ) { // (--i) done at the end of the loop.
547 i -= (uses_found - 1);
548 }
549 }
550 else {
551 assert( igvn->eqv(n->in(0), this), "Expect RegionNode to be control parent");
552 n->set_req(0, parent_ctrl);
553 }
554 #ifdef ASSERT
555 for( uint k=0; k < n->req(); k++ ) {
556 assert( !igvn->eqv(n->in(k), this), "All uses of RegionNode should be gone");
557 }
558 #endif
559 }
560 // Remove the RegionNode itself from DefUse info
561 igvn->remove_dead_node(this);
562 return NULL;
563 }
564 return this; // Record progress
565 }
566
567
568 // If a Region flows into a Region, merge into one big happy merge.
569 if (can_reshape) {
570 Node *m = merge_region(this, phase);
571 if (m != NULL) return m;
572 }
573
574 // Check if this region is the root of a clipping idiom on floats
575 if( ConvertFloat2IntClipping && can_reshape && req() == 4 ) {
576 // Check that only one use is a Phi and that it simplifies to two constants +
577 PhiNode* phi = has_unique_phi();
578 if (phi != NULL) { // One Phi user
579 // Check inputs to the Phi
580 ConNode *min;
581 ConNode *max;
582 Node *val;
583 uint min_idx;
584 uint max_idx;
585 uint val_idx;
586 if( check_phi_clipping( phi, min, min_idx, max, max_idx, val, val_idx ) ) {
587 IfNode *top_if;
588 IfNode *bot_if;
589 if( check_if_clipping( this, bot_if, top_if ) ) {
590 // Control pattern checks, now verify compares
591 Node *top_in = NULL; // value being compared against
592 Node *bot_in = NULL;
593 if( check_compare_clipping( true, bot_if, min, bot_in ) &&
594 check_compare_clipping( false, top_if, max, top_in ) ) {
595 if( bot_in == top_in ) {
596 PhaseIterGVN *gvn = phase->is_IterGVN();
597 assert( gvn != NULL, "Only had DefUse info in IterGVN");
598 // Only remaining check is that bot_in == top_in == (Phi's val + mods)
599
600 // Check for the ConvF2INode
601 ConvF2INode *convf2i;
602 if( check_convf2i_clipping( phi, val_idx, convf2i, min, max ) &&
603 convf2i->in(1) == bot_in ) {
604 // Matched pattern, including LShiftI; RShiftI, replace with integer compares
605 // max test
606 Node *cmp = gvn->register_new_node_with_optimizer(new (phase->C, 3) CmpINode( convf2i, min ));
607 Node *boo = gvn->register_new_node_with_optimizer(new (phase->C, 2) BoolNode( cmp, BoolTest::lt ));
608 IfNode *iff = (IfNode*)gvn->register_new_node_with_optimizer(new (phase->C, 2) IfNode( top_if->in(0), boo, PROB_UNLIKELY_MAG(5), top_if->_fcnt ));
609 Node *if_min= gvn->register_new_node_with_optimizer(new (phase->C, 1) IfTrueNode (iff));
610 Node *ifF = gvn->register_new_node_with_optimizer(new (phase->C, 1) IfFalseNode(iff));
611 // min test
612 cmp = gvn->register_new_node_with_optimizer(new (phase->C, 3) CmpINode( convf2i, max ));
613 boo = gvn->register_new_node_with_optimizer(new (phase->C, 2) BoolNode( cmp, BoolTest::gt ));
614 iff = (IfNode*)gvn->register_new_node_with_optimizer(new (phase->C, 2) IfNode( ifF, boo, PROB_UNLIKELY_MAG(5), bot_if->_fcnt ));
615 Node *if_max= gvn->register_new_node_with_optimizer(new (phase->C, 1) IfTrueNode (iff));
616 ifF = gvn->register_new_node_with_optimizer(new (phase->C, 1) IfFalseNode(iff));
617 // update input edges to region node
618 set_req_X( min_idx, if_min, gvn );
619 set_req_X( max_idx, if_max, gvn );
620 set_req_X( val_idx, ifF, gvn );
621 // remove unnecessary 'LShiftI; RShiftI' idiom
622 gvn->hash_delete(phi);
623 phi->set_req_X( val_idx, convf2i, gvn );
624 gvn->hash_find_insert(phi);
625 // Return transformed region node
626 return this;
627 }
628 }
629 }
630 }
631 }
632 }
633 }
634
635 return NULL;
636 }
637
638
639
640 const RegMask &RegionNode::out_RegMask() const {
641 return RegMask::Empty;
642 }
643
644 // Find the one non-null required input. RegionNode only
645 Node *Node::nonnull_req() const {
646 assert( is_Region(), "" );
647 for( uint i = 1; i < _cnt; i++ )
648 if( in(i) )
649 return in(i);
650 ShouldNotReachHere();
651 return NULL;
652 }
653
654
655 //=============================================================================
656 // note that these functions assume that the _adr_type field is flattened
657 uint PhiNode::hash() const {
658 const Type* at = _adr_type;
659 return TypeNode::hash() + (at ? at->hash() : 0);
660 }
661 uint PhiNode::cmp( const Node &n ) const {
662 return TypeNode::cmp(n) && _adr_type == ((PhiNode&)n)._adr_type;
663 }
664 static inline
665 const TypePtr* flatten_phi_adr_type(const TypePtr* at) {
666 if (at == NULL || at == TypePtr::BOTTOM) return at;
667 return Compile::current()->alias_type(at)->adr_type();
668 }
669
670 //----------------------------make---------------------------------------------
671 // create a new phi with edges matching r and set (initially) to x
672 PhiNode* PhiNode::make(Node* r, Node* x, const Type *t, const TypePtr* at) {
673 uint preds = r->req(); // Number of predecessor paths
674 assert(t != Type::MEMORY || at == flatten_phi_adr_type(at), "flatten at");
675 PhiNode* p = new (Compile::current(), preds) PhiNode(r, t, at);
676 for (uint j = 1; j < preds; j++) {
677 // Fill in all inputs, except those which the region does not yet have
678 if (r->in(j) != NULL)
679 p->init_req(j, x);
680 }
681 return p;
682 }
683 PhiNode* PhiNode::make(Node* r, Node* x) {
684 const Type* t = x->bottom_type();
685 const TypePtr* at = NULL;
686 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type());
687 return make(r, x, t, at);
688 }
689 PhiNode* PhiNode::make_blank(Node* r, Node* x) {
690 const Type* t = x->bottom_type();
691 const TypePtr* at = NULL;
692 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type());
693 return new (Compile::current(), r->req()) PhiNode(r, t, at);
694 }
695
696
697 //------------------------slice_memory-----------------------------------------
698 // create a new phi with narrowed memory type
699 PhiNode* PhiNode::slice_memory(const TypePtr* adr_type) const {
700 PhiNode* mem = (PhiNode*) clone();
701 *(const TypePtr**)&mem->_adr_type = adr_type;
702 // convert self-loops, or else we get a bad graph
703 for (uint i = 1; i < req(); i++) {
704 if ((const Node*)in(i) == this) mem->set_req(i, mem);
705 }
706 mem->verify_adr_type();
707 return mem;
708 }
709
710 //------------------------split_out_instance-----------------------------------
711 // Split out an instance type from a bottom phi.
712 PhiNode* PhiNode::split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const {
713 const TypeOopPtr *t_oop = at->isa_oopptr();
714 assert(t_oop != NULL && t_oop->is_known_instance(), "expecting instance oopptr");
715 const TypePtr *t = adr_type();
716 assert(type() == Type::MEMORY &&
717 (t == TypePtr::BOTTOM || t == TypeRawPtr::BOTTOM ||
718 t->isa_oopptr() && !t->is_oopptr()->is_known_instance() &&
719 t->is_oopptr()->cast_to_exactness(true)
720 ->is_oopptr()->cast_to_ptr_type(t_oop->ptr())
721 ->is_oopptr()->cast_to_instance_id(t_oop->instance_id()) == t_oop),
722 "bottom or raw memory required");
723
724 // Check if an appropriate node already exists.
725 Node *region = in(0);
726 for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) {
727 Node* use = region->fast_out(k);
728 if( use->is_Phi()) {
729 PhiNode *phi2 = use->as_Phi();
730 if (phi2->type() == Type::MEMORY && phi2->adr_type() == at) {
731 return phi2;
732 }
733 }
734 }
735 Compile *C = igvn->C;
736 Arena *a = Thread::current()->resource_area();
737 Node_Array node_map = new Node_Array(a);
738 Node_Stack stack(a, C->unique() >> 4);
739 PhiNode *nphi = slice_memory(at);
740 igvn->register_new_node_with_optimizer( nphi );
741 node_map.map(_idx, nphi);
742 stack.push((Node *)this, 1);
743 while(!stack.is_empty()) {
744 PhiNode *ophi = stack.node()->as_Phi();
745 uint i = stack.index();
746 assert(i >= 1, "not control edge");
747 stack.pop();
748 nphi = node_map[ophi->_idx]->as_Phi();
749 for (; i < ophi->req(); i++) {
750 Node *in = ophi->in(i);
751 if (in == NULL || igvn->type(in) == Type::TOP)
752 continue;
753 Node *opt = MemNode::optimize_simple_memory_chain(in, at, igvn);
754 PhiNode *optphi = opt->is_Phi() ? opt->as_Phi() : NULL;
755 if (optphi != NULL && optphi->adr_type() == TypePtr::BOTTOM) {
756 opt = node_map[optphi->_idx];
757 if (opt == NULL) {
758 stack.push(ophi, i);
759 nphi = optphi->slice_memory(at);
760 igvn->register_new_node_with_optimizer( nphi );
761 node_map.map(optphi->_idx, nphi);
762 ophi = optphi;
763 i = 0; // will get incremented at top of loop
764 continue;
765 }
766 }
767 nphi->set_req(i, opt);
768 }
769 }
770 return nphi;
771 }
772
773 //------------------------verify_adr_type--------------------------------------
774 #ifdef ASSERT
775 void PhiNode::verify_adr_type(VectorSet& visited, const TypePtr* at) const {
776 if (visited.test_set(_idx)) return; //already visited
777
778 // recheck constructor invariants:
779 verify_adr_type(false);
780
781 // recheck local phi/phi consistency:
782 assert(_adr_type == at || _adr_type == TypePtr::BOTTOM,
783 "adr_type must be consistent across phi nest");
784
785 // walk around
786 for (uint i = 1; i < req(); i++) {
787 Node* n = in(i);
788 if (n == NULL) continue;
789 const Node* np = in(i);
790 if (np->is_Phi()) {
791 np->as_Phi()->verify_adr_type(visited, at);
792 } else if (n->bottom_type() == Type::TOP
793 || (n->is_Mem() && n->in(MemNode::Address)->bottom_type() == Type::TOP)) {
794 // ignore top inputs
795 } else {
796 const TypePtr* nat = flatten_phi_adr_type(n->adr_type());
797 // recheck phi/non-phi consistency at leaves:
798 assert((nat != NULL) == (at != NULL), "");
799 assert(nat == at || nat == TypePtr::BOTTOM,
800 "adr_type must be consistent at leaves of phi nest");
801 }
802 }
803 }
804
805 // Verify a whole nest of phis rooted at this one.
806 void PhiNode::verify_adr_type(bool recursive) const {
807 if (is_error_reported()) return; // muzzle asserts when debugging an error
808 if (Node::in_dump()) return; // muzzle asserts when printing
809
810 assert((_type == Type::MEMORY) == (_adr_type != NULL), "adr_type for memory phis only");
811
812 if (!VerifyAliases) return; // verify thoroughly only if requested
813
814 assert(_adr_type == flatten_phi_adr_type(_adr_type),
815 "Phi::adr_type must be pre-normalized");
816
817 if (recursive) {
818 VectorSet visited(Thread::current()->resource_area());
819 verify_adr_type(visited, _adr_type);
820 }
821 }
822 #endif
823
824
825 //------------------------------Value------------------------------------------
826 // Compute the type of the PhiNode
827 const Type *PhiNode::Value( PhaseTransform *phase ) const {
828 Node *r = in(0); // RegionNode
829 if( !r ) // Copy or dead
830 return in(1) ? phase->type(in(1)) : Type::TOP;
831
832 // Note: During parsing, phis are often transformed before their regions.
833 // This means we have to use type_or_null to defend against untyped regions.
834 if( phase->type_or_null(r) == Type::TOP ) // Dead code?
835 return Type::TOP;
836
837 // Check for trip-counted loop. If so, be smarter.
838 CountedLoopNode *l = r->is_CountedLoop() ? r->as_CountedLoop() : NULL;
839 if( l && l->can_be_counted_loop(phase) &&
840 ((const Node*)l->phi() == this) ) { // Trip counted loop!
841 // protect against init_trip() or limit() returning NULL
842 const Node *init = l->init_trip();
843 const Node *limit = l->limit();
844 if( init != NULL && limit != NULL && l->stride_is_con() ) {
845 const TypeInt *lo = init ->bottom_type()->isa_int();
846 const TypeInt *hi = limit->bottom_type()->isa_int();
847 if( lo && hi ) { // Dying loops might have TOP here
848 int stride = l->stride_con();
849 if( stride < 0 ) { // Down-counter loop
850 const TypeInt *tmp = lo; lo = hi; hi = tmp;
851 stride = -stride;
852 }
853 if( lo->_hi < hi->_lo ) // Reversed endpoints are well defined :-(
854 return TypeInt::make(lo->_lo,hi->_hi,3);
855 }
856 }
857 }
858
859 // Until we have harmony between classes and interfaces in the type
860 // lattice, we must tread carefully around phis which implicitly
861 // convert the one to the other.
862 const TypePtr* ttp = _type->make_ptr();
863 const TypeInstPtr* ttip = (ttp != NULL) ? ttp->isa_instptr() : NULL;
864 const TypeKlassPtr* ttkp = (ttp != NULL) ? ttp->isa_klassptr() : NULL;
865 bool is_intf = false;
866 if (ttip != NULL) {
867 ciKlass* k = ttip->klass();
868 if (k->is_loaded() && k->is_interface())
869 is_intf = true;
870 }
871 if (ttkp != NULL) {
872 ciKlass* k = ttkp->klass();
873 if (k->is_loaded() && k->is_interface())
874 is_intf = true;
875 }
876
877 // Default case: merge all inputs
878 const Type *t = Type::TOP; // Merged type starting value
879 for (uint i = 1; i < req(); ++i) {// For all paths in
880 // Reachable control path?
881 if (r->in(i) && phase->type(r->in(i)) == Type::CONTROL) {
882 const Type* ti = phase->type(in(i));
883 // We assume that each input of an interface-valued Phi is a true
884 // subtype of that interface. This might not be true of the meet
885 // of all the input types. The lattice is not distributive in
886 // such cases. Ward off asserts in type.cpp by refusing to do
887 // meets between interfaces and proper classes.
888 const TypePtr* tip = ti->make_ptr();
889 const TypeInstPtr* tiip = (tip != NULL) ? tip->isa_instptr() : NULL;
890 if (tiip) {
891 bool ti_is_intf = false;
892 ciKlass* k = tiip->klass();
893 if (k->is_loaded() && k->is_interface())
894 ti_is_intf = true;
895 if (is_intf != ti_is_intf)
896 { t = _type; break; }
897 }
898 t = t->meet(ti);
899 }
900 }
901
902 // The worst-case type (from ciTypeFlow) should be consistent with "t".
903 // That is, we expect that "t->higher_equal(_type)" holds true.
904 // There are various exceptions:
905 // - Inputs which are phis might in fact be widened unnecessarily.
906 // For example, an input might be a widened int while the phi is a short.
907 // - Inputs might be BotPtrs but this phi is dependent on a null check,
908 // and postCCP has removed the cast which encodes the result of the check.
909 // - The type of this phi is an interface, and the inputs are classes.
910 // - Value calls on inputs might produce fuzzy results.
911 // (Occurrences of this case suggest improvements to Value methods.)
912 //
913 // It is not possible to see Type::BOTTOM values as phi inputs,
914 // because the ciTypeFlow pre-pass produces verifier-quality types.
915 const Type* ft = t->filter(_type); // Worst case type
916
917 #ifdef ASSERT
918 // The following logic has been moved into TypeOopPtr::filter.
919 const Type* jt = t->join(_type);
920 if( jt->empty() ) { // Emptied out???
921
922 // Check for evil case of 't' being a class and '_type' expecting an
923 // interface. This can happen because the bytecodes do not contain
924 // enough type info to distinguish a Java-level interface variable
925 // from a Java-level object variable. If we meet 2 classes which
926 // both implement interface I, but their meet is at 'j/l/O' which
927 // doesn't implement I, we have no way to tell if the result should
928 // be 'I' or 'j/l/O'. Thus we'll pick 'j/l/O'. If this then flows
929 // into a Phi which "knows" it's an Interface type we'll have to
930 // uplift the type.
931 if( !t->empty() && ttip && ttip->is_loaded() && ttip->klass()->is_interface() )
932 { assert(ft == _type, ""); } // Uplift to interface
933 else if( !t->empty() && ttkp && ttkp->is_loaded() && ttkp->klass()->is_interface() )
934 { assert(ft == _type, ""); } // Uplift to interface
935 // Otherwise it's something stupid like non-overlapping int ranges
936 // found on dying counted loops.
937 else
938 { assert(ft == Type::TOP, ""); } // Canonical empty value
939 }
940
941 else {
942
943 // If we have an interface-typed Phi and we narrow to a class type, the join
944 // should report back the class. However, if we have a J/L/Object
945 // class-typed Phi and an interface flows in, it's possible that the meet &
946 // join report an interface back out. This isn't possible but happens
947 // because the type system doesn't interact well with interfaces.
948 const TypePtr *jtp = jt->make_ptr();
949 const TypeInstPtr *jtip = (jtp != NULL) ? jtp->isa_instptr() : NULL;
950 const TypeKlassPtr *jtkp = (jtp != NULL) ? jtp->isa_klassptr() : NULL;
951 if( jtip && ttip ) {
952 if( jtip->is_loaded() && jtip->klass()->is_interface() &&
953 ttip->is_loaded() && !ttip->klass()->is_interface() ) {
954 // Happens in a CTW of rt.jar, 320-341, no extra flags
955 assert(ft == ttip->cast_to_ptr_type(jtip->ptr()) ||
956 ft->isa_narrowoop() && ft->make_ptr() == ttip->cast_to_ptr_type(jtip->ptr()), "");
957 jt = ft;
958 }
959 }
960 if( jtkp && ttkp ) {
961 if( jtkp->is_loaded() && jtkp->klass()->is_interface() &&
962 ttkp->is_loaded() && !ttkp->klass()->is_interface() ) {
963 assert(ft == ttkp->cast_to_ptr_type(jtkp->ptr()) ||
964 ft->isa_narrowoop() && ft->make_ptr() == ttkp->cast_to_ptr_type(jtkp->ptr()), "");
965 jt = ft;
966 }
967 }
968 if (jt != ft && jt->base() == ft->base()) {
969 if (jt->isa_int() &&
970 jt->is_int()->_lo == ft->is_int()->_lo &&
971 jt->is_int()->_hi == ft->is_int()->_hi)
972 jt = ft;
973 if (jt->isa_long() &&
974 jt->is_long()->_lo == ft->is_long()->_lo &&
975 jt->is_long()->_hi == ft->is_long()->_hi)
976 jt = ft;
977 }
978 if (jt != ft) {
979 tty->print("merge type: "); t->dump(); tty->cr();
980 tty->print("kill type: "); _type->dump(); tty->cr();
981 tty->print("join type: "); jt->dump(); tty->cr();
982 tty->print("filter type: "); ft->dump(); tty->cr();
983 }
984 assert(jt == ft, "");
985 }
986 #endif //ASSERT
987
988 // Deal with conversion problems found in data loops.
989 ft = phase->saturate(ft, phase->type_or_null(this), _type);
990
991 return ft;
992 }
993
994
995 //------------------------------is_diamond_phi---------------------------------
996 // Does this Phi represent a simple well-shaped diamond merge? Return the
997 // index of the true path or 0 otherwise.
998 int PhiNode::is_diamond_phi() const {
999 // Check for a 2-path merge
1000 Node *region = in(0);
1001 if( !region ) return 0;
1002 if( region->req() != 3 ) return 0;
1003 if( req() != 3 ) return 0;
1004 // Check that both paths come from the same If
1005 Node *ifp1 = region->in(1);
1006 Node *ifp2 = region->in(2);
1007 if( !ifp1 || !ifp2 ) return 0;
1008 Node *iff = ifp1->in(0);
1009 if( !iff || !iff->is_If() ) return 0;
1010 if( iff != ifp2->in(0) ) return 0;
1011 // Check for a proper bool/cmp
1012 const Node *b = iff->in(1);
1013 if( !b->is_Bool() ) return 0;
1014 const Node *cmp = b->in(1);
1015 if( !cmp->is_Cmp() ) return 0;
1016
1017 // Check for branching opposite expected
1018 if( ifp2->Opcode() == Op_IfTrue ) {
1019 assert( ifp1->Opcode() == Op_IfFalse, "" );
1020 return 2;
1021 } else {
1022 assert( ifp1->Opcode() == Op_IfTrue, "" );
1023 return 1;
1024 }
1025 }
1026
1027 //----------------------------check_cmove_id-----------------------------------
1028 // Check for CMove'ing a constant after comparing against the constant.
1029 // Happens all the time now, since if we compare equality vs a constant in
1030 // the parser, we "know" the variable is constant on one path and we force
1031 // it. Thus code like "if( x==0 ) {/*EMPTY*/}" ends up inserting a
1032 // conditional move: "x = (x==0)?0:x;". Yucko. This fix is slightly more
1033 // general in that we don't need constants. Since CMove's are only inserted
1034 // in very special circumstances, we do it here on generic Phi's.
1035 Node* PhiNode::is_cmove_id(PhaseTransform* phase, int true_path) {
1036 assert(true_path !=0, "only diamond shape graph expected");
1037
1038 // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1039 // phi->region->if_proj->ifnode->bool->cmp
1040 Node* region = in(0);
1041 Node* iff = region->in(1)->in(0);
1042 BoolNode* b = iff->in(1)->as_Bool();
1043 Node* cmp = b->in(1);
1044 Node* tval = in(true_path);
1045 Node* fval = in(3-true_path);
1046 Node* id = CMoveNode::is_cmove_id(phase, cmp, tval, fval, b);
1047 if (id == NULL)
1048 return NULL;
1049
1050 // Either value might be a cast that depends on a branch of 'iff'.
1051 // Since the 'id' value will float free of the diamond, either
1052 // decast or return failure.
1053 Node* ctl = id->in(0);
1054 if (ctl != NULL && ctl->in(0) == iff) {
1055 if (id->is_ConstraintCast()) {
1056 return id->in(1);
1057 } else {
1058 // Don't know how to disentangle this value.
1059 return NULL;
1060 }
1061 }
1062
1063 return id;
1064 }
1065
1066 //------------------------------Identity---------------------------------------
1067 // Check for Region being Identity.
1068 Node *PhiNode::Identity( PhaseTransform *phase ) {
1069 // Check for no merging going on
1070 // (There used to be special-case code here when this->region->is_Loop.
1071 // It would check for a tributary phi on the backedge that the main phi
1072 // trivially, perhaps with a single cast. The unique_input method
1073 // does all this and more, by reducing such tributaries to 'this'.)
1074 Node* uin = unique_input(phase);
1075 if (uin != NULL) {
1076 return uin;
1077 }
1078
1079 int true_path = is_diamond_phi();
1080 if (true_path != 0) {
1081 Node* id = is_cmove_id(phase, true_path);
1082 if (id != NULL) return id;
1083 }
1084
1085 return this; // No identity
1086 }
1087
1088 //-----------------------------unique_input------------------------------------
1089 // Find the unique value, discounting top, self-loops, and casts.
1090 // Return top if there are no inputs, and self if there are multiple.
1091 Node* PhiNode::unique_input(PhaseTransform* phase) {
1092 // 1) One unique direct input, or
1093 // 2) some of the inputs have an intervening ConstraintCast and
1094 // the type of input is the same or sharper (more specific)
1095 // than the phi's type.
1096 // 3) an input is a self loop
1097 //
1098 // 1) input or 2) input or 3) input __
1099 // / \ / \ \ / \
1100 // \ / | cast phi cast
1101 // phi \ / / \ /
1102 // phi / --
1103
1104 Node* r = in(0); // RegionNode
1105 if (r == NULL) return in(1); // Already degraded to a Copy
1106 Node* uncasted_input = NULL; // The unique uncasted input (ConstraintCasts removed)
1107 Node* direct_input = NULL; // The unique direct input
1108
1109 for (uint i = 1, cnt = req(); i < cnt; ++i) {
1110 Node* rc = r->in(i);
1111 if (rc == NULL || phase->type(rc) == Type::TOP)
1112 continue; // ignore unreachable control path
1113 Node* n = in(i);
1114 if (n == NULL)
1115 continue;
1116 Node* un = n->uncast();
1117 if (un == NULL || un == this || phase->type(un) == Type::TOP) {
1118 continue; // ignore if top, or in(i) and "this" are in a data cycle
1119 }
1120 // Check for a unique uncasted input
1121 if (uncasted_input == NULL) {
1122 uncasted_input = un;
1123 } else if (uncasted_input != un) {
1124 uncasted_input = NodeSentinel; // no unique uncasted input
1125 }
1126 // Check for a unique direct input
1127 if (direct_input == NULL) {
1128 direct_input = n;
1129 } else if (direct_input != n) {
1130 direct_input = NodeSentinel; // no unique direct input
1131 }
1132 }
1133 if (direct_input == NULL) {
1134 return phase->C->top(); // no inputs
1135 }
1136 assert(uncasted_input != NULL,"");
1137
1138 if (direct_input != NodeSentinel) {
1139 return direct_input; // one unique direct input
1140 }
1141 if (uncasted_input != NodeSentinel &&
1142 phase->type(uncasted_input)->higher_equal(type())) {
1143 return uncasted_input; // one unique uncasted input
1144 }
1145
1146 // Nothing.
1147 return NULL;
1148 }
1149
1150 //------------------------------is_x2logic-------------------------------------
1151 // Check for simple convert-to-boolean pattern
1152 // If:(C Bool) Region:(IfF IfT) Phi:(Region 0 1)
1153 // Convert Phi to an ConvIB.
1154 static Node *is_x2logic( PhaseGVN *phase, PhiNode *phi, int true_path ) {
1155 assert(true_path !=0, "only diamond shape graph expected");
1156 // Convert the true/false index into an expected 0/1 return.
1157 // Map 2->0 and 1->1.
1158 int flipped = 2-true_path;
1159
1160 // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1161 // phi->region->if_proj->ifnode->bool->cmp
1162 Node *region = phi->in(0);
1163 Node *iff = region->in(1)->in(0);
1164 BoolNode *b = (BoolNode*)iff->in(1);
1165 const CmpNode *cmp = (CmpNode*)b->in(1);
1166
1167 Node *zero = phi->in(1);
1168 Node *one = phi->in(2);
1169 const Type *tzero = phase->type( zero );
1170 const Type *tone = phase->type( one );
1171
1172 // Check for compare vs 0
1173 const Type *tcmp = phase->type(cmp->in(2));
1174 if( tcmp != TypeInt::ZERO && tcmp != TypePtr::NULL_PTR ) {
1175 // Allow cmp-vs-1 if the other input is bounded by 0-1
1176 if( !(tcmp == TypeInt::ONE && phase->type(cmp->in(1)) == TypeInt::BOOL) )
1177 return NULL;
1178 flipped = 1-flipped; // Test is vs 1 instead of 0!
1179 }
1180
1181 // Check for setting zero/one opposite expected
1182 if( tzero == TypeInt::ZERO ) {
1183 if( tone == TypeInt::ONE ) {
1184 } else return NULL;
1185 } else if( tzero == TypeInt::ONE ) {
1186 if( tone == TypeInt::ZERO ) {
1187 flipped = 1-flipped;
1188 } else return NULL;
1189 } else return NULL;
1190
1191 // Check for boolean test backwards
1192 if( b->_test._test == BoolTest::ne ) {
1193 } else if( b->_test._test == BoolTest::eq ) {
1194 flipped = 1-flipped;
1195 } else return NULL;
1196
1197 // Build int->bool conversion
1198 Node *n = new (phase->C, 2) Conv2BNode( cmp->in(1) );
1199 if( flipped )
1200 n = new (phase->C, 3) XorINode( phase->transform(n), phase->intcon(1) );
1201
1202 return n;
1203 }
1204
1205 //------------------------------is_cond_add------------------------------------
1206 // Check for simple conditional add pattern: "(P < Q) ? X+Y : X;"
1207 // To be profitable the control flow has to disappear; there can be no other
1208 // values merging here. We replace the test-and-branch with:
1209 // "(sgn(P-Q))&Y) + X". Basically, convert "(P < Q)" into 0 or -1 by
1210 // moving the carry bit from (P-Q) into a register with 'sbb EAX,EAX'.
1211 // Then convert Y to 0-or-Y and finally add.
1212 // This is a key transform for SpecJava _201_compress.
1213 static Node* is_cond_add(PhaseGVN *phase, PhiNode *phi, int true_path) {
1214 assert(true_path !=0, "only diamond shape graph expected");
1215
1216 // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1217 // phi->region->if_proj->ifnode->bool->cmp
1218 RegionNode *region = (RegionNode*)phi->in(0);
1219 Node *iff = region->in(1)->in(0);
1220 BoolNode* b = iff->in(1)->as_Bool();
1221 const CmpNode *cmp = (CmpNode*)b->in(1);
1222
1223 // Make sure only merging this one phi here
1224 if (region->has_unique_phi() != phi) return NULL;
1225
1226 // Make sure each arm of the diamond has exactly one output, which we assume
1227 // is the region. Otherwise, the control flow won't disappear.
1228 if (region->in(1)->outcnt() != 1) return NULL;
1229 if (region->in(2)->outcnt() != 1) return NULL;
1230
1231 // Check for "(P < Q)" of type signed int
1232 if (b->_test._test != BoolTest::lt) return NULL;
1233 if (cmp->Opcode() != Op_CmpI) return NULL;
1234
1235 Node *p = cmp->in(1);
1236 Node *q = cmp->in(2);
1237 Node *n1 = phi->in( true_path);
1238 Node *n2 = phi->in(3-true_path);
1239
1240 int op = n1->Opcode();
1241 if( op != Op_AddI // Need zero as additive identity
1242 /*&&op != Op_SubI &&
1243 op != Op_AddP &&
1244 op != Op_XorI &&
1245 op != Op_OrI*/ )
1246 return NULL;
1247
1248 Node *x = n2;
1249 Node *y = n1->in(1);
1250 if( n2 == n1->in(1) ) {
1251 y = n1->in(2);
1252 } else if( n2 == n1->in(1) ) {
1253 } else return NULL;
1254
1255 // Not so profitable if compare and add are constants
1256 if( q->is_Con() && phase->type(q) != TypeInt::ZERO && y->is_Con() )
1257 return NULL;
1258
1259 Node *cmplt = phase->transform( new (phase->C, 3) CmpLTMaskNode(p,q) );
1260 Node *j_and = phase->transform( new (phase->C, 3) AndINode(cmplt,y) );
1261 return new (phase->C, 3) AddINode(j_and,x);
1262 }
1263
1264 //------------------------------is_absolute------------------------------------
1265 // Check for absolute value.
1266 static Node* is_absolute( PhaseGVN *phase, PhiNode *phi_root, int true_path) {
1267 assert(true_path !=0, "only diamond shape graph expected");
1268
1269 int cmp_zero_idx = 0; // Index of compare input where to look for zero
1270 int phi_x_idx = 0; // Index of phi input where to find naked x
1271
1272 // ABS ends with the merge of 2 control flow paths.
1273 // Find the false path from the true path. With only 2 inputs, 3 - x works nicely.
1274 int false_path = 3 - true_path;
1275
1276 // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1277 // phi->region->if_proj->ifnode->bool->cmp
1278 BoolNode *bol = phi_root->in(0)->in(1)->in(0)->in(1)->as_Bool();
1279
1280 // Check bool sense
1281 switch( bol->_test._test ) {
1282 case BoolTest::lt: cmp_zero_idx = 1; phi_x_idx = true_path; break;
1283 case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break;
1284 case BoolTest::gt: cmp_zero_idx = 2; phi_x_idx = true_path; break;
1285 case BoolTest::ge: cmp_zero_idx = 1; phi_x_idx = false_path; break;
1286 default: return NULL; break;
1287 }
1288
1289 // Test is next
1290 Node *cmp = bol->in(1);
1291 const Type *tzero = NULL;
1292 switch( cmp->Opcode() ) {
1293 case Op_CmpF: tzero = TypeF::ZERO; break; // Float ABS
1294 case Op_CmpD: tzero = TypeD::ZERO; break; // Double ABS
1295 default: return NULL;
1296 }
1297
1298 // Find zero input of compare; the other input is being abs'd
1299 Node *x = NULL;
1300 bool flip = false;
1301 if( phase->type(cmp->in(cmp_zero_idx)) == tzero ) {
1302 x = cmp->in(3 - cmp_zero_idx);
1303 } else if( phase->type(cmp->in(3 - cmp_zero_idx)) == tzero ) {
1304 // The test is inverted, we should invert the result...
1305 x = cmp->in(cmp_zero_idx);
1306 flip = true;
1307 } else {
1308 return NULL;
1309 }
1310
1311 // Next get the 2 pieces being selected, one is the original value
1312 // and the other is the negated value.
1313 if( phi_root->in(phi_x_idx) != x ) return NULL;
1314
1315 // Check other phi input for subtract node
1316 Node *sub = phi_root->in(3 - phi_x_idx);
1317
1318 // Allow only Sub(0,X) and fail out for all others; Neg is not OK
1319 if( tzero == TypeF::ZERO ) {
1320 if( sub->Opcode() != Op_SubF ||
1321 sub->in(2) != x ||
1322 phase->type(sub->in(1)) != tzero ) return NULL;
1323 x = new (phase->C, 2) AbsFNode(x);
1324 if (flip) {
1325 x = new (phase->C, 3) SubFNode(sub->in(1), phase->transform(x));
1326 }
1327 } else {
1328 if( sub->Opcode() != Op_SubD ||
1329 sub->in(2) != x ||
1330 phase->type(sub->in(1)) != tzero ) return NULL;
1331 x = new (phase->C, 2) AbsDNode(x);
1332 if (flip) {
1333 x = new (phase->C, 3) SubDNode(sub->in(1), phase->transform(x));
1334 }
1335 }
1336
1337 return x;
1338 }
1339
1340 //------------------------------split_once-------------------------------------
1341 // Helper for split_flow_path
1342 static void split_once(PhaseIterGVN *igvn, Node *phi, Node *val, Node *n, Node *newn) {
1343 igvn->hash_delete(n); // Remove from hash before hacking edges
1344
1345 uint j = 1;
1346 for( uint i = phi->req()-1; i > 0; i-- ) {
1347 if( phi->in(i) == val ) { // Found a path with val?
1348 // Add to NEW Region/Phi, no DU info
1349 newn->set_req( j++, n->in(i) );
1350 // Remove from OLD Region/Phi
1351 n->del_req(i);
1352 }
1353 }
1354
1355 // Register the new node but do not transform it. Cannot transform until the
1356 // entire Region/Phi conglerate has been hacked as a single huge transform.
1357 igvn->register_new_node_with_optimizer( newn );
1358 // Now I can point to the new node.
1359 n->add_req(newn);
1360 igvn->_worklist.push(n);
1361 }
1362
1363 //------------------------------split_flow_path--------------------------------
1364 // Check for merging identical values and split flow paths
1365 static Node* split_flow_path(PhaseGVN *phase, PhiNode *phi) {
1366 BasicType bt = phi->type()->basic_type();
1367 if( bt == T_ILLEGAL || type2size[bt] <= 0 )
1368 return NULL; // Bail out on funny non-value stuff
1369 if( phi->req() <= 3 ) // Need at least 2 matched inputs and a
1370 return NULL; // third unequal input to be worth doing
1371
1372 // Scan for a constant
1373 uint i;
1374 for( i = 1; i < phi->req()-1; i++ ) {
1375 Node *n = phi->in(i);
1376 if( !n ) return NULL;
1377 if( phase->type(n) == Type::TOP ) return NULL;
1378 if( n->Opcode() == Op_ConP || n->Opcode() == Op_ConN )
1379 break;
1380 }
1381 if( i >= phi->req() ) // Only split for constants
1382 return NULL;
1383
1384 Node *val = phi->in(i); // Constant to split for
1385 uint hit = 0; // Number of times it occurs
1386
1387 for( ; i < phi->req(); i++ ){ // Count occurances of constant
1388 Node *n = phi->in(i);
1389 if( !n ) return NULL;
1390 if( phase->type(n) == Type::TOP ) return NULL;
1391 if( phi->in(i) == val )
1392 hit++;
1393 }
1394
1395 if( hit <= 1 || // Make sure we find 2 or more
1396 hit == phi->req()-1 ) // and not ALL the same value
1397 return NULL;
1398
1399 // Now start splitting out the flow paths that merge the same value.
1400 // Split first the RegionNode.
1401 PhaseIterGVN *igvn = phase->is_IterGVN();
1402 Node *r = phi->region();
1403 RegionNode *newr = new (phase->C, hit+1) RegionNode(hit+1);
1404 split_once(igvn, phi, val, r, newr);
1405
1406 // Now split all other Phis than this one
1407 for (DUIterator_Fast kmax, k = r->fast_outs(kmax); k < kmax; k++) {
1408 Node* phi2 = r->fast_out(k);
1409 if( phi2->is_Phi() && phi2->as_Phi() != phi ) {
1410 PhiNode *newphi = PhiNode::make_blank(newr, phi2);
1411 split_once(igvn, phi, val, phi2, newphi);
1412 }
1413 }
1414
1415 // Clean up this guy
1416 igvn->hash_delete(phi);
1417 for( i = phi->req()-1; i > 0; i-- ) {
1418 if( phi->in(i) == val ) {
1419 phi->del_req(i);
1420 }
1421 }
1422 phi->add_req(val);
1423
1424 return phi;
1425 }
1426
1427 //=============================================================================
1428 //------------------------------simple_data_loop_check-------------------------
1429 // Try to determing if the phi node in a simple safe/unsafe data loop.
1430 // Returns:
1431 // enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop };
1432 // Safe - safe case when the phi and it's inputs reference only safe data
1433 // nodes;
1434 // Unsafe - the phi and it's inputs reference unsafe data nodes but there
1435 // is no reference back to the phi - need a graph walk
1436 // to determine if it is in a loop;
1437 // UnsafeLoop - unsafe case when the phi references itself directly or through
1438 // unsafe data node.
1439 // Note: a safe data node is a node which could/never reference itself during
1440 // GVN transformations. For now it is Con, Proj, Phi, CastPP, CheckCastPP.
1441 // I mark Phi nodes as safe node not only because they can reference itself
1442 // but also to prevent mistaking the fallthrough case inside an outer loop
1443 // as dead loop when the phi references itselfs through an other phi.
1444 PhiNode::LoopSafety PhiNode::simple_data_loop_check(Node *in) const {
1445 // It is unsafe loop if the phi node references itself directly.
1446 if (in == (Node*)this)
1447 return UnsafeLoop; // Unsafe loop
1448 // Unsafe loop if the phi node references itself through an unsafe data node.
1449 // Exclude cases with null inputs or data nodes which could reference
1450 // itself (safe for dead loops).
1451 if (in != NULL && !in->is_dead_loop_safe()) {
1452 // Check inputs of phi's inputs also.
1453 // It is much less expensive then full graph walk.
1454 uint cnt = in->req();
1455 uint i = (in->is_Proj() && !in->is_CFG()) ? 0 : 1;
1456 for (; i < cnt; ++i) {
1457 Node* m = in->in(i);
1458 if (m == (Node*)this)
1459 return UnsafeLoop; // Unsafe loop
1460 if (m != NULL && !m->is_dead_loop_safe()) {
1461 // Check the most common case (about 30% of all cases):
1462 // phi->Load/Store->AddP->(ConP ConP Con)/(Parm Parm Con).
1463 Node *m1 = (m->is_AddP() && m->req() > 3) ? m->in(1) : NULL;
1464 if (m1 == (Node*)this)
1465 return UnsafeLoop; // Unsafe loop
1466 if (m1 != NULL && m1 == m->in(2) &&
1467 m1->is_dead_loop_safe() && m->in(3)->is_Con()) {
1468 continue; // Safe case
1469 }
1470 // The phi references an unsafe node - need full analysis.
1471 return Unsafe;
1472 }
1473 }
1474 }
1475 return Safe; // Safe case - we can optimize the phi node.
1476 }
1477
1478 //------------------------------is_unsafe_data_reference-----------------------
1479 // If phi can be reached through the data input - it is data loop.
1480 bool PhiNode::is_unsafe_data_reference(Node *in) const {
1481 assert(req() > 1, "");
1482 // First, check simple cases when phi references itself directly or
1483 // through an other node.
1484 LoopSafety safety = simple_data_loop_check(in);
1485 if (safety == UnsafeLoop)
1486 return true; // phi references itself - unsafe loop
1487 else if (safety == Safe)
1488 return false; // Safe case - phi could be replaced with the unique input.
1489
1490 // Unsafe case when we should go through data graph to determine
1491 // if the phi references itself.
1492
1493 ResourceMark rm;
1494
1495 Arena *a = Thread::current()->resource_area();
1496 Node_List nstack(a);
1497 VectorSet visited(a);
1498
1499 nstack.push(in); // Start with unique input.
1500 visited.set(in->_idx);
1501 while (nstack.size() != 0) {
1502 Node* n = nstack.pop();
1503 uint cnt = n->req();
1504 uint i = (n->is_Proj() && !n->is_CFG()) ? 0 : 1;
1505 for (; i < cnt; i++) {
1506 Node* m = n->in(i);
1507 if (m == (Node*)this) {
1508 return true; // Data loop
1509 }
1510 if (m != NULL && !m->is_dead_loop_safe()) { // Only look for unsafe cases.
1511 if (!visited.test_set(m->_idx))
1512 nstack.push(m);
1513 }
1514 }
1515 }
1516 return false; // The phi is not reachable from its inputs
1517 }
1518
1519
1520 //------------------------------Ideal------------------------------------------
1521 // Return a node which is more "ideal" than the current node. Must preserve
1522 // the CFG, but we can still strip out dead paths.
1523 Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1524 // The next should never happen after 6297035 fix.
1525 if( is_copy() ) // Already degraded to a Copy ?
1526 return NULL; // No change
1527
1528 Node *r = in(0); // RegionNode
1529 assert(r->in(0) == NULL || !r->in(0)->is_Root(), "not a specially hidden merge");
1530
1531 // Note: During parsing, phis are often transformed before their regions.
1532 // This means we have to use type_or_null to defend against untyped regions.
1533 if( phase->type_or_null(r) == Type::TOP ) // Dead code?
1534 return NULL; // No change
1535
1536 Node *top = phase->C->top();
1537
1538 // The are 2 situations when only one valid phi's input is left
1539 // (in addition to Region input).
1540 // One: region is not loop - replace phi with this input.
1541 // Two: region is loop - replace phi with top since this data path is dead
1542 // and we need to break the dead data loop.
1543 Node* progress = NULL; // Record if any progress made
1544 for( uint j = 1; j < req(); ++j ){ // For all paths in
1545 // Check unreachable control paths
1546 Node* rc = r->in(j);
1547 Node* n = in(j); // Get the input
1548 if (rc == NULL || phase->type(rc) == Type::TOP) {
1549 if (n != top) { // Not already top?
1550 set_req(j, top); // Nuke it down
1551 progress = this; // Record progress
1552 }
1553 }
1554 }
1555
1556 Node* uin = unique_input(phase);
1557 if (uin == top) { // Simplest case: no alive inputs.
1558 if (can_reshape) // IGVN transformation
1559 return top;
1560 else
1561 return NULL; // Identity will return TOP
1562 } else if (uin != NULL) {
1563 // Only one not-NULL unique input path is left.
1564 // Determine if this input is backedge of a loop.
1565 // (Skip new phis which have no uses and dead regions).
1566 if( outcnt() > 0 && r->in(0) != NULL ) {
1567 // First, take the short cut when we know it is a loop and
1568 // the EntryControl data path is dead.
1569 assert(!r->is_Loop() || r->req() == 3, "Loop node should have 3 inputs");
1570 // Then, check if there is a data loop when phi references itself directly
1571 // or through other data nodes.
1572 if( r->is_Loop() && !phase->eqv_uncast(uin, in(LoopNode::EntryControl)) ||
1573 !r->is_Loop() && is_unsafe_data_reference(uin) ) {
1574 // Break this data loop to avoid creation of a dead loop.
1575 if (can_reshape) {
1576 return top;
1577 } else {
1578 // We can't return top if we are in Parse phase - cut inputs only
1579 // let Identity to handle the case.
1580 replace_edge(uin, top);
1581 return NULL;
1582 }
1583 }
1584 }
1585
1586 // One unique input.
1587 debug_only(Node* ident = Identity(phase));
1588 // The unique input must eventually be detected by the Identity call.
1589 #ifdef ASSERT
1590 if (ident != uin && !ident->is_top()) {
1591 // print this output before failing assert
1592 r->dump(3);
1593 this->dump(3);
1594 ident->dump();
1595 uin->dump();
1596 }
1597 #endif
1598 assert(ident == uin || ident->is_top(), "Identity must clean this up");
1599 return NULL;
1600 }
1601
1602
1603 Node* opt = NULL;
1604 int true_path = is_diamond_phi();
1605 if( true_path != 0 ) {
1606 // Check for CMove'ing identity. If it would be unsafe,
1607 // handle it here. In the safe case, let Identity handle it.
1608 Node* unsafe_id = is_cmove_id(phase, true_path);
1609 if( unsafe_id != NULL && is_unsafe_data_reference(unsafe_id) )
1610 opt = unsafe_id;
1611
1612 // Check for simple convert-to-boolean pattern
1613 if( opt == NULL )
1614 opt = is_x2logic(phase, this, true_path);
1615
1616 // Check for absolute value
1617 if( opt == NULL )
1618 opt = is_absolute(phase, this, true_path);
1619
1620 // Check for conditional add
1621 if( opt == NULL && can_reshape )
1622 opt = is_cond_add(phase, this, true_path);
1623
1624 // These 4 optimizations could subsume the phi:
1625 // have to check for a dead data loop creation.
1626 if( opt != NULL ) {
1627 if( opt == unsafe_id || is_unsafe_data_reference(opt) ) {
1628 // Found dead loop.
1629 if( can_reshape )
1630 return top;
1631 // We can't return top if we are in Parse phase - cut inputs only
1632 // to stop further optimizations for this phi. Identity will return TOP.
1633 assert(req() == 3, "only diamond merge phi here");
1634 set_req(1, top);
1635 set_req(2, top);
1636 return NULL;
1637 } else {
1638 return opt;
1639 }
1640 }
1641 }
1642
1643 // Check for merging identical values and split flow paths
1644 if (can_reshape) {
1645 opt = split_flow_path(phase, this);
1646 // This optimization only modifies phi - don't need to check for dead loop.
1647 assert(opt == NULL || phase->eqv(opt, this), "do not elide phi");
1648 if (opt != NULL) return opt;
1649 }
1650
1651 // Split phis through memory merges, so that the memory merges will go away.
1652 // Piggy-back this transformation on the search for a unique input....
1653 // It will be as if the merged memory is the unique value of the phi.
1654 // (Do not attempt this optimization unless parsing is complete.
1655 // It would make the parser's memory-merge logic sick.)
1656 // (MergeMemNode is not dead_loop_safe - need to check for dead loop.)
1657 if (progress == NULL && can_reshape && type() == Type::MEMORY) {
1658 // see if this phi should be sliced
1659 uint merge_width = 0;
1660 bool saw_self = false;
1661 for( uint i=1; i<req(); ++i ) {// For all paths in
1662 Node *ii = in(i);
1663 if (ii->is_MergeMem()) {
1664 MergeMemNode* n = ii->as_MergeMem();
1665 merge_width = MAX2(merge_width, n->req());
1666 saw_self = saw_self || phase->eqv(n->base_memory(), this);
1667 }
1668 }
1669
1670 // This restriction is temporarily necessary to ensure termination:
1671 if (!saw_self && adr_type() == TypePtr::BOTTOM) merge_width = 0;
1672
1673 if (merge_width > Compile::AliasIdxRaw) {
1674 // found at least one non-empty MergeMem
1675 const TypePtr* at = adr_type();
1676 if (at != TypePtr::BOTTOM) {
1677 // Patch the existing phi to select an input from the merge:
1678 // Phi:AT1(...MergeMem(m0, m1, m2)...) into
1679 // Phi:AT1(...m1...)
1680 int alias_idx = phase->C->get_alias_index(at);
1681 for (uint i=1; i<req(); ++i) {
1682 Node *ii = in(i);
1683 if (ii->is_MergeMem()) {
1684 MergeMemNode* n = ii->as_MergeMem();
1685 // compress paths and change unreachable cycles to TOP
1686 // If not, we can update the input infinitely along a MergeMem cycle
1687 // Equivalent code is in MemNode::Ideal_common
1688 Node *m = phase->transform(n);
1689 if (outcnt() == 0) { // Above transform() may kill us!
1690 progress = phase->C->top();
1691 break;
1692 }
1693 // If tranformed to a MergeMem, get the desired slice
1694 // Otherwise the returned node represents memory for every slice
1695 Node *new_mem = (m->is_MergeMem()) ?
1696 m->as_MergeMem()->memory_at(alias_idx) : m;
1697 // Update input if it is progress over what we have now
1698 if (new_mem != ii) {
1699 set_req(i, new_mem);
1700 progress = this;
1701 }
1702 }
1703 }
1704 } else {
1705 // We know that at least one MergeMem->base_memory() == this
1706 // (saw_self == true). If all other inputs also references this phi
1707 // (directly or through data nodes) - it is dead loop.
1708 bool saw_safe_input = false;
1709 for (uint j = 1; j < req(); ++j) {
1710 Node *n = in(j);
1711 if (n->is_MergeMem() && n->as_MergeMem()->base_memory() == this)
1712 continue; // skip known cases
1713 if (!is_unsafe_data_reference(n)) {
1714 saw_safe_input = true; // found safe input
1715 break;
1716 }
1717 }
1718 if (!saw_safe_input)
1719 return top; // all inputs reference back to this phi - dead loop
1720
1721 // Phi(...MergeMem(m0, m1:AT1, m2:AT2)...) into
1722 // MergeMem(Phi(...m0...), Phi:AT1(...m1...), Phi:AT2(...m2...))
1723 PhaseIterGVN *igvn = phase->is_IterGVN();
1724 Node* hook = new (phase->C, 1) Node(1);
1725 PhiNode* new_base = (PhiNode*) clone();
1726 // Must eagerly register phis, since they participate in loops.
1727 if (igvn) {
1728 igvn->register_new_node_with_optimizer(new_base);
1729 hook->add_req(new_base);
1730 }
1731 MergeMemNode* result = MergeMemNode::make(phase->C, new_base);
1732 for (uint i = 1; i < req(); ++i) {
1733 Node *ii = in(i);
1734 if (ii->is_MergeMem()) {
1735 MergeMemNode* n = ii->as_MergeMem();
1736 for (MergeMemStream mms(result, n); mms.next_non_empty2(); ) {
1737 // If we have not seen this slice yet, make a phi for it.
1738 bool made_new_phi = false;
1739 if (mms.is_empty()) {
1740 Node* new_phi = new_base->slice_memory(mms.adr_type(phase->C));
1741 made_new_phi = true;
1742 if (igvn) {
1743 igvn->register_new_node_with_optimizer(new_phi);
1744 hook->add_req(new_phi);
1745 }
1746 mms.set_memory(new_phi);
1747 }
1748 Node* phi = mms.memory();
1749 assert(made_new_phi || phi->in(i) == n, "replace the i-th merge by a slice");
1750 phi->set_req(i, mms.memory2());
1751 }
1752 }
1753 }
1754 // Distribute all self-loops.
1755 { // (Extra braces to hide mms.)
1756 for (MergeMemStream mms(result); mms.next_non_empty(); ) {
1757 Node* phi = mms.memory();
1758 for (uint i = 1; i < req(); ++i) {
1759 if (phi->in(i) == this) phi->set_req(i, phi);
1760 }
1761 }
1762 }
1763 // now transform the new nodes, and return the mergemem
1764 for (MergeMemStream mms(result); mms.next_non_empty(); ) {
1765 Node* phi = mms.memory();
1766 mms.set_memory(phase->transform(phi));
1767 }
1768 if (igvn) { // Unhook.
1769 igvn->hash_delete(hook);
1770 for (uint i = 1; i < hook->req(); i++) {
1771 hook->set_req(i, NULL);
1772 }
1773 }
1774 // Replace self with the result.
1775 return result;
1776 }
1777 }
1778 //
1779 // Other optimizations on the memory chain
1780 //
1781 const TypePtr* at = adr_type();
1782 for( uint i=1; i<req(); ++i ) {// For all paths in
1783 Node *ii = in(i);
1784 Node *new_in = MemNode::optimize_memory_chain(ii, at, phase);
1785 if (ii != new_in ) {
1786 set_req(i, new_in);
1787 progress = this;
1788 }
1789 }
1790 }
1791
1792 #ifdef _LP64
1793 // Push DecodeN down through phi.
1794 // The rest of phi graph will transform by split EncodeP node though phis up.
1795 if (UseCompressedOops && can_reshape && progress == NULL) {
1796 bool may_push = true;
1797 bool has_decodeN = false;
1798 Node* in_decodeN = NULL;
1799 for (uint i=1; i<req(); ++i) {// For all paths in
1800 Node *ii = in(i);
1801 if (ii->is_DecodeN() && ii->bottom_type() == bottom_type()) {
1802 has_decodeN = true;
1803 in_decodeN = ii->in(1);
1804 } else if (!ii->is_Phi()) {
1805 may_push = false;
1806 }
1807 }
1808
1809 if (has_decodeN && may_push) {
1810 PhaseIterGVN *igvn = phase->is_IterGVN();
1811 // Note: in_decodeN is used only to define the type of new phi here.
1812 PhiNode *new_phi = PhiNode::make_blank(in(0), in_decodeN);
1813 uint orig_cnt = req();
1814 for (uint i=1; i<req(); ++i) {// For all paths in
1815 Node *ii = in(i);
1816 Node* new_ii = NULL;
1817 if (ii->is_DecodeN()) {
1818 assert(ii->bottom_type() == bottom_type(), "sanity");
1819 new_ii = ii->in(1);
1820 } else {
1821 assert(ii->is_Phi(), "sanity");
1822 if (ii->as_Phi() == this) {
1823 new_ii = new_phi;
1824 } else {
1825 new_ii = new (phase->C, 2) EncodePNode(ii, in_decodeN->bottom_type());
1826 igvn->register_new_node_with_optimizer(new_ii);
1827 }
1828 }
1829 new_phi->set_req(i, new_ii);
1830 }
1831 igvn->register_new_node_with_optimizer(new_phi, this);
1832 progress = new (phase->C, 2) DecodeNNode(new_phi, bottom_type());
1833 }
1834 }
1835 #endif
1836
1837 return progress; // Return any progress
1838 }
1839
1840 //------------------------------is_tripcount-----------------------------------
1841 bool PhiNode::is_tripcount() const {
1842 return (in(0) != NULL && in(0)->is_CountedLoop() &&
1843 in(0)->as_CountedLoop()->phi() == this);
1844 }
1845
1846 //------------------------------out_RegMask------------------------------------
1847 const RegMask &PhiNode::in_RegMask(uint i) const {
1848 return i ? out_RegMask() : RegMask::Empty;
1849 }
1850
1851 const RegMask &PhiNode::out_RegMask() const {
1852 uint ideal_reg = Matcher::base2reg[_type->base()];
1853 assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" );
1854 if( ideal_reg == 0 ) return RegMask::Empty;
1855 return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]);
1856 }
1857
1858 #ifndef PRODUCT
1859 void PhiNode::dump_spec(outputStream *st) const {
1860 TypeNode::dump_spec(st);
1861 if (is_tripcount()) {
1862 st->print(" #tripcount");
1863 }
1864 }
1865 #endif
1866
1867
1868 //=============================================================================
1869 const Type *GotoNode::Value( PhaseTransform *phase ) const {
1870 // If the input is reachable, then we are executed.
1871 // If the input is not reachable, then we are not executed.
1872 return phase->type(in(0));
1873 }
1874
1875 Node *GotoNode::Identity( PhaseTransform *phase ) {
1876 return in(0); // Simple copy of incoming control
1877 }
1878
1879 const RegMask &GotoNode::out_RegMask() const {
1880 return RegMask::Empty;
1881 }
1882
1883 //=============================================================================
1884 const RegMask &JumpNode::out_RegMask() const {
1885 return RegMask::Empty;
1886 }
1887
1888 //=============================================================================
1889 const RegMask &JProjNode::out_RegMask() const {
1890 return RegMask::Empty;
1891 }
1892
1893 //=============================================================================
1894 const RegMask &CProjNode::out_RegMask() const {
1895 return RegMask::Empty;
1896 }
1897
1898
1899
1900 //=============================================================================
1901
1902 uint PCTableNode::hash() const { return Node::hash() + _size; }
1903 uint PCTableNode::cmp( const Node &n ) const
1904 { return _size == ((PCTableNode&)n)._size; }
1905
1906 const Type *PCTableNode::bottom_type() const {
1907 const Type** f = TypeTuple::fields(_size);
1908 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL;
1909 return TypeTuple::make(_size, f);
1910 }
1911
1912 //------------------------------Value------------------------------------------
1913 // Compute the type of the PCTableNode. If reachable it is a tuple of
1914 // Control, otherwise the table targets are not reachable
1915 const Type *PCTableNode::Value( PhaseTransform *phase ) const {
1916 if( phase->type(in(0)) == Type::CONTROL )
1917 return bottom_type();
1918 return Type::TOP; // All paths dead? Then so are we
1919 }
1920
1921 //------------------------------Ideal------------------------------------------
1922 // Return a node which is more "ideal" than the current node. Strip out
1923 // control copies
1924 Node *PCTableNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1925 return remove_dead_region(phase, can_reshape) ? this : NULL;
1926 }
1927
1928 //=============================================================================
1929 uint JumpProjNode::hash() const {
1930 return Node::hash() + _dest_bci;
1931 }
1932
1933 uint JumpProjNode::cmp( const Node &n ) const {
1934 return ProjNode::cmp(n) &&
1935 _dest_bci == ((JumpProjNode&)n)._dest_bci;
1936 }
1937
1938 #ifndef PRODUCT
1939 void JumpProjNode::dump_spec(outputStream *st) const {
1940 ProjNode::dump_spec(st);
1941 st->print("@bci %d ",_dest_bci);
1942 }
1943 #endif
1944
1945 //=============================================================================
1946 //------------------------------Value------------------------------------------
1947 // Check for being unreachable, or for coming from a Rethrow. Rethrow's cannot
1948 // have the default "fall_through_index" path.
1949 const Type *CatchNode::Value( PhaseTransform *phase ) const {
1950 // Unreachable? Then so are all paths from here.
1951 if( phase->type(in(0)) == Type::TOP ) return Type::TOP;
1952 // First assume all paths are reachable
1953 const Type** f = TypeTuple::fields(_size);
1954 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL;
1955 // Identify cases that will always throw an exception
1956 // () rethrow call
1957 // () virtual or interface call with NULL receiver
1958 // () call is a check cast with incompatible arguments
1959 if( in(1)->is_Proj() ) {
1960 Node *i10 = in(1)->in(0);
1961 if( i10->is_Call() ) {
1962 CallNode *call = i10->as_Call();
1963 // Rethrows always throw exceptions, never return
1964 if (call->entry_point() == OptoRuntime::rethrow_stub()) {
1965 f[CatchProjNode::fall_through_index] = Type::TOP;
1966 } else if( call->req() > TypeFunc::Parms ) {
1967 const Type *arg0 = phase->type( call->in(TypeFunc::Parms) );
1968 // Check for null reciever to virtual or interface calls
1969 if( call->is_CallDynamicJava() &&
1970 arg0->higher_equal(TypePtr::NULL_PTR) ) {
1971 f[CatchProjNode::fall_through_index] = Type::TOP;
1972 }
1973 } // End of if not a runtime stub
1974 } // End of if have call above me
1975 } // End of slot 1 is not a projection
1976 return TypeTuple::make(_size, f);
1977 }
1978
1979 //=============================================================================
1980 uint CatchProjNode::hash() const {
1981 return Node::hash() + _handler_bci;
1982 }
1983
1984
1985 uint CatchProjNode::cmp( const Node &n ) const {
1986 return ProjNode::cmp(n) &&
1987 _handler_bci == ((CatchProjNode&)n)._handler_bci;
1988 }
1989
1990
1991 //------------------------------Identity---------------------------------------
1992 // If only 1 target is possible, choose it if it is the main control
1993 Node *CatchProjNode::Identity( PhaseTransform *phase ) {
1994 // If my value is control and no other value is, then treat as ID
1995 const TypeTuple *t = phase->type(in(0))->is_tuple();
1996 if (t->field_at(_con) != Type::CONTROL) return this;
1997 // If we remove the last CatchProj and elide the Catch/CatchProj, then we
1998 // also remove any exception table entry. Thus we must know the call
1999 // feeding the Catch will not really throw an exception. This is ok for
2000 // the main fall-thru control (happens when we know a call can never throw
2001 // an exception) or for "rethrow", because a further optimnization will
2002 // yank the rethrow (happens when we inline a function that can throw an
2003 // exception and the caller has no handler). Not legal, e.g., for passing
2004 // a NULL receiver to a v-call, or passing bad types to a slow-check-cast.
2005 // These cases MUST throw an exception via the runtime system, so the VM
2006 // will be looking for a table entry.
2007 Node *proj = in(0)->in(1); // Expect a proj feeding CatchNode
2008 CallNode *call;
2009 if (_con != TypeFunc::Control && // Bail out if not the main control.
2010 !(proj->is_Proj() && // AND NOT a rethrow
2011 proj->in(0)->is_Call() &&
2012 (call = proj->in(0)->as_Call()) &&
2013 call->entry_point() == OptoRuntime::rethrow_stub()))
2014 return this;
2015
2016 // Search for any other path being control
2017 for (uint i = 0; i < t->cnt(); i++) {
2018 if (i != _con && t->field_at(i) == Type::CONTROL)
2019 return this;
2020 }
2021 // Only my path is possible; I am identity on control to the jump
2022 return in(0)->in(0);
2023 }
2024
2025
2026 #ifndef PRODUCT
2027 void CatchProjNode::dump_spec(outputStream *st) const {
2028 ProjNode::dump_spec(st);
2029 st->print("@bci %d ",_handler_bci);
2030 }
2031 #endif
2032
2033 //=============================================================================
2034 //------------------------------Identity---------------------------------------
2035 // Check for CreateEx being Identity.
2036 Node *CreateExNode::Identity( PhaseTransform *phase ) {
2037 if( phase->type(in(1)) == Type::TOP ) return in(1);
2038 if( phase->type(in(0)) == Type::TOP ) return in(0);
2039 // We only come from CatchProj, unless the CatchProj goes away.
2040 // If the CatchProj is optimized away, then we just carry the
2041 // exception oop through.
2042 CallNode *call = in(1)->in(0)->as_Call();
2043
2044 return ( in(0)->is_CatchProj() && in(0)->in(0)->in(1) == in(1) )
2045 ? this
2046 : call->in(TypeFunc::Parms);
2047 }
2048
2049 //=============================================================================
2050 //------------------------------Value------------------------------------------
2051 // Check for being unreachable.
2052 const Type *NeverBranchNode::Value( PhaseTransform *phase ) const {
2053 if (!in(0) || in(0)->is_top()) return Type::TOP;
2054 return bottom_type();
2055 }
2056
2057 //------------------------------Ideal------------------------------------------
2058 // Check for no longer being part of a loop
2059 Node *NeverBranchNode::Ideal(PhaseGVN *phase, bool can_reshape) {
2060 if (can_reshape && !in(0)->is_Loop()) {
2061 // Dead code elimination can sometimes delete this projection so
2062 // if it's not there, there's nothing to do.
2063 Node* fallthru = proj_out(0);
2064 if (fallthru != NULL) {
2065 phase->is_IterGVN()->subsume_node(fallthru, in(0));
2066 }
2067 return phase->C->top();
2068 }
2069 return NULL;
2070 }
2071
2072 #ifndef PRODUCT
2073 void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const {
2074 st->print("%s", Name());
2075 }
2076 #endif
2077