1 /*
2 * Copyright (c) 1997, 2022, 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.
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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.
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23 */
24
25 #include "precompiled.hpp"
26 #include "gc/shared/barrierSet.hpp"
27 #include "gc/shared/c2/barrierSetC2.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "oops/objArrayKlass.hpp"
31 #include "opto/addnode.hpp"
32 #include "opto/castnode.hpp"
33 #include "opto/cfgnode.hpp"
34 #include "opto/connode.hpp"
35 #include "opto/convertnode.hpp"
36 #include "opto/inlinetypenode.hpp"
37 #include "opto/loopnode.hpp"
38 #include "opto/machnode.hpp"
39 #include "opto/movenode.hpp"
40 #include "opto/narrowptrnode.hpp"
41 #include "opto/mulnode.hpp"
42 #include "opto/phaseX.hpp"
43 #include "opto/regmask.hpp"
44 #include "opto/runtime.hpp"
45 #include "opto/subnode.hpp"
46 #include "opto/vectornode.hpp"
47 #include "utilities/vmError.hpp"
48
49 // Portions of code courtesy of Clifford Click
50
51 // Optimization - Graph Style
52
53 //=============================================================================
54 //------------------------------Value------------------------------------------
55 // Compute the type of the RegionNode.
56 const Type* RegionNode::Value(PhaseGVN* phase) const {
57 for( uint i=1; i<req(); ++i ) { // For all paths in
58 Node *n = in(i); // Get Control source
59 if( !n ) continue; // Missing inputs are TOP
60 if( phase->type(n) == Type::CONTROL )
61 return Type::CONTROL;
62 }
63 return Type::TOP; // All paths dead? Then so are we
64 }
65
66 //------------------------------Identity---------------------------------------
67 // Check for Region being Identity.
68 Node* RegionNode::Identity(PhaseGVN* phase) {
69 // Cannot have Region be an identity, even if it has only 1 input.
70 // Phi users cannot have their Region input folded away for them,
71 // since they need to select the proper data input
72 return this;
73 }
74
75 //------------------------------merge_region-----------------------------------
76 // If a Region flows into a Region, merge into one big happy merge. This is
77 // hard to do if there is stuff that has to happen
78 static Node *merge_region(RegionNode *region, PhaseGVN *phase) {
79 if( region->Opcode() != Op_Region ) // Do not do to LoopNodes
80 return NULL;
81 Node *progress = NULL; // Progress flag
82 PhaseIterGVN *igvn = phase->is_IterGVN();
83
84 uint rreq = region->req();
85 for( uint i = 1; i < rreq; i++ ) {
86 Node *r = region->in(i);
87 if( r && r->Opcode() == Op_Region && // Found a region?
88 r->in(0) == r && // Not already collapsed?
89 r != region && // Avoid stupid situations
90 r->outcnt() == 2 ) { // Self user and 'region' user only?
91 assert(!r->as_Region()->has_phi(), "no phi users");
92 if( !progress ) { // No progress
93 if (region->has_phi()) {
94 return NULL; // Only flatten if no Phi users
95 // igvn->hash_delete( phi );
96 }
97 igvn->hash_delete( region );
98 progress = region; // Making progress
99 }
100 igvn->hash_delete( r );
101
102 // Append inputs to 'r' onto 'region'
103 for( uint j = 1; j < r->req(); j++ ) {
104 // Move an input from 'r' to 'region'
105 region->add_req(r->in(j));
106 r->set_req(j, phase->C->top());
107 // Update phis of 'region'
108 //for( uint k = 0; k < max; k++ ) {
109 // Node *phi = region->out(k);
110 // if( phi->is_Phi() ) {
111 // phi->add_req(phi->in(i));
112 // }
113 //}
114
115 rreq++; // One more input to Region
116 } // Found a region to merge into Region
117 igvn->_worklist.push(r);
118 // Clobber pointer to the now dead 'r'
119 region->set_req(i, phase->C->top());
120 }
121 }
122
123 return progress;
124 }
125
126
127
128 //--------------------------------has_phi--------------------------------------
129 // Helper function: Return any PhiNode that uses this region or NULL
130 PhiNode* RegionNode::has_phi() const {
131 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
132 Node* phi = fast_out(i);
133 if (phi->is_Phi()) { // Check for Phi users
134 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)");
135 return phi->as_Phi(); // this one is good enough
136 }
137 }
138
139 return NULL;
140 }
141
142
143 //-----------------------------has_unique_phi----------------------------------
144 // Helper function: Return the only PhiNode that uses this region or NULL
145 PhiNode* RegionNode::has_unique_phi() const {
146 // Check that only one use is a Phi
147 PhiNode* only_phi = NULL;
148 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
149 Node* phi = fast_out(i);
150 if (phi->is_Phi()) { // Check for Phi users
151 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)");
152 if (only_phi == NULL) {
153 only_phi = phi->as_Phi();
154 } else {
155 return NULL; // multiple phis
156 }
157 }
158 }
159
160 return only_phi;
161 }
162
163
164 //------------------------------check_phi_clipping-----------------------------
165 // Helper function for RegionNode's identification of FP clipping
166 // Check inputs to the Phi
167 static bool check_phi_clipping( PhiNode *phi, ConNode * &min, uint &min_idx, ConNode * &max, uint &max_idx, Node * &val, uint &val_idx ) {
168 min = NULL;
169 max = NULL;
170 val = NULL;
171 min_idx = 0;
172 max_idx = 0;
173 val_idx = 0;
174 uint phi_max = phi->req();
175 if( phi_max == 4 ) {
176 for( uint j = 1; j < phi_max; ++j ) {
177 Node *n = phi->in(j);
178 int opcode = n->Opcode();
179 switch( opcode ) {
180 case Op_ConI:
181 {
182 if( min == NULL ) {
183 min = n->Opcode() == Op_ConI ? (ConNode*)n : NULL;
184 min_idx = j;
185 } else {
186 max = n->Opcode() == Op_ConI ? (ConNode*)n : NULL;
187 max_idx = j;
188 if( min->get_int() > max->get_int() ) {
189 // Swap min and max
190 ConNode *temp;
191 uint temp_idx;
192 temp = min; min = max; max = temp;
193 temp_idx = min_idx; min_idx = max_idx; max_idx = temp_idx;
194 }
195 }
196 }
197 break;
198 default:
199 {
200 val = n;
201 val_idx = j;
202 }
203 break;
204 }
205 }
206 }
207 return ( min && max && val && (min->get_int() <= 0) && (max->get_int() >=0) );
208 }
209
210
211 //------------------------------check_if_clipping------------------------------
212 // Helper function for RegionNode's identification of FP clipping
213 // Check that inputs to Region come from two IfNodes,
214 //
215 // If
216 // False True
217 // If |
218 // False True |
219 // | | |
220 // RegionNode_inputs
221 //
222 static bool check_if_clipping( const RegionNode *region, IfNode * &bot_if, IfNode * &top_if ) {
223 top_if = NULL;
224 bot_if = NULL;
225
226 // Check control structure above RegionNode for (if ( if ) )
227 Node *in1 = region->in(1);
228 Node *in2 = region->in(2);
229 Node *in3 = region->in(3);
230 // Check that all inputs are projections
231 if( in1->is_Proj() && in2->is_Proj() && in3->is_Proj() ) {
232 Node *in10 = in1->in(0);
233 Node *in20 = in2->in(0);
234 Node *in30 = in3->in(0);
235 // Check that #1 and #2 are ifTrue and ifFalse from same If
236 if( in10 != NULL && in10->is_If() &&
237 in20 != NULL && in20->is_If() &&
238 in30 != NULL && in30->is_If() && in10 == in20 &&
239 (in1->Opcode() != in2->Opcode()) ) {
240 Node *in100 = in10->in(0);
241 Node *in1000 = (in100 != NULL && in100->is_Proj()) ? in100->in(0) : NULL;
242 // Check that control for in10 comes from other branch of IF from in3
243 if( in1000 != NULL && in1000->is_If() &&
244 in30 == in1000 && (in3->Opcode() != in100->Opcode()) ) {
245 // Control pattern checks
246 top_if = (IfNode*)in1000;
247 bot_if = (IfNode*)in10;
248 }
249 }
250 }
251
252 return (top_if != NULL);
253 }
254
255
256 //------------------------------check_convf2i_clipping-------------------------
257 // Helper function for RegionNode's identification of FP clipping
258 // Verify that the value input to the phi comes from "ConvF2I; LShift; RShift"
259 static bool check_convf2i_clipping( PhiNode *phi, uint idx, ConvF2INode * &convf2i, Node *min, Node *max) {
260 convf2i = NULL;
261
262 // Check for the RShiftNode
263 Node *rshift = phi->in(idx);
264 assert( rshift, "Previous checks ensure phi input is present");
265 if( rshift->Opcode() != Op_RShiftI ) { return false; }
266
267 // Check for the LShiftNode
268 Node *lshift = rshift->in(1);
269 assert( lshift, "Previous checks ensure phi input is present");
270 if( lshift->Opcode() != Op_LShiftI ) { return false; }
271
272 // Check for the ConvF2INode
273 Node *conv = lshift->in(1);
274 if( conv->Opcode() != Op_ConvF2I ) { return false; }
275
276 // Check that shift amounts are only to get sign bits set after F2I
277 jint max_cutoff = max->get_int();
278 jint min_cutoff = min->get_int();
279 jint left_shift = lshift->in(2)->get_int();
280 jint right_shift = rshift->in(2)->get_int();
281 jint max_post_shift = nth_bit(BitsPerJavaInteger - left_shift - 1);
282 if( left_shift != right_shift ||
283 0 > left_shift || left_shift >= BitsPerJavaInteger ||
284 max_post_shift < max_cutoff ||
285 max_post_shift < -min_cutoff ) {
286 // Shifts are necessary but current transformation eliminates them
287 return false;
288 }
289
290 // OK to return the result of ConvF2I without shifting
291 convf2i = (ConvF2INode*)conv;
292 return true;
293 }
294
295
296 //------------------------------check_compare_clipping-------------------------
297 // Helper function for RegionNode's identification of FP clipping
298 static bool check_compare_clipping( bool less_than, IfNode *iff, ConNode *limit, Node * & input ) {
299 Node *i1 = iff->in(1);
300 if ( !i1->is_Bool() ) { return false; }
301 BoolNode *bool1 = i1->as_Bool();
302 if( less_than && bool1->_test._test != BoolTest::le ) { return false; }
303 else if( !less_than && bool1->_test._test != BoolTest::lt ) { return false; }
304 const Node *cmpF = bool1->in(1);
305 if( cmpF->Opcode() != Op_CmpF ) { return false; }
306 // Test that the float value being compared against
307 // is equivalent to the int value used as a limit
308 Node *nodef = cmpF->in(2);
309 if( nodef->Opcode() != Op_ConF ) { return false; }
310 jfloat conf = nodef->getf();
311 jint coni = limit->get_int();
312 if( ((int)conf) != coni ) { return false; }
313 input = cmpF->in(1);
314 return true;
315 }
316
317 //------------------------------is_unreachable_region--------------------------
318 // Check if the RegionNode is part of an unsafe loop and unreachable from root.
319 bool RegionNode::is_unreachable_region(const PhaseGVN* phase) {
320 Node* top = phase->C->top();
321 assert(req() == 2 || (req() == 3 && in(1) != NULL && in(2) == top), "sanity check arguments");
322 if (_is_unreachable_region) {
323 // Return cached result from previous evaluation which should still be valid
324 assert(is_unreachable_from_root(phase), "walk the graph again and check if its indeed unreachable");
325 return true;
326 }
327
328 // First, cut the simple case of fallthrough region when NONE of
329 // region's phis references itself directly or through a data node.
330 if (is_possible_unsafe_loop(phase)) {
331 // If we have a possible unsafe loop, check if the region node is actually unreachable from root.
332 if (is_unreachable_from_root(phase)) {
333 _is_unreachable_region = true;
334 return true;
335 }
336 }
337 return false;
338 }
339
340 bool RegionNode::is_possible_unsafe_loop(const PhaseGVN* phase) const {
341 uint max = outcnt();
342 uint i;
343 for (i = 0; i < max; i++) {
344 Node* n = raw_out(i);
345 if (n != NULL && n->is_Phi()) {
346 PhiNode* phi = n->as_Phi();
347 assert(phi->in(0) == this, "sanity check phi");
348 if (phi->outcnt() == 0) {
349 continue; // Safe case - no loops
350 }
351 if (phi->outcnt() == 1) {
352 Node* u = phi->raw_out(0);
353 // Skip if only one use is an other Phi or Call or Uncommon trap.
354 // It is safe to consider this case as fallthrough.
355 if (u != NULL && (u->is_Phi() || u->is_CFG())) {
356 continue;
357 }
358 }
359 // Check when phi references itself directly or through an other node.
360 if (phi->as_Phi()->simple_data_loop_check(phi->in(1)) >= PhiNode::Unsafe) {
361 break; // Found possible unsafe data loop.
362 }
363 }
364 }
365 if (i >= max) {
366 return false; // An unsafe case was NOT found - don't need graph walk.
367 }
368 return true;
369 }
370
371 bool RegionNode::is_unreachable_from_root(const PhaseGVN* phase) const {
372 ResourceMark rm;
373 Node_List nstack;
374 VectorSet visited;
375
376 // Mark all control nodes reachable from root outputs
377 Node* n = (Node*)phase->C->root();
378 nstack.push(n);
379 visited.set(n->_idx);
380 while (nstack.size() != 0) {
381 n = nstack.pop();
382 uint max = n->outcnt();
383 for (uint i = 0; i < max; i++) {
384 Node* m = n->raw_out(i);
385 if (m != NULL && m->is_CFG()) {
386 if (m == this) {
387 return false; // We reached the Region node - it is not dead.
388 }
389 if (!visited.test_set(m->_idx))
390 nstack.push(m);
391 }
392 }
393 }
394 return true; // The Region node is unreachable - it is dead.
395 }
396
397 Node* PhiNode::try_clean_mem_phi(PhaseGVN *phase) {
398 // Incremental inlining + PhaseStringOpts sometimes produce:
399 //
400 // cmpP with 1 top input
401 // |
402 // If
403 // / \
404 // IfFalse IfTrue /- Some Node
405 // \ / / /
406 // Region / /-MergeMem
407 // \---Phi
408 //
409 //
410 // It's expected by PhaseStringOpts that the Region goes away and is
411 // replaced by If's control input but because there's still a Phi,
412 // the Region stays in the graph. The top input from the cmpP is
413 // propagated forward and a subgraph that is useful goes away. The
414 // code below replaces the Phi with the MergeMem so that the Region
415 // is simplified.
416
417 if (type() == Type::MEMORY && is_diamond_phi(true)) {
418 MergeMemNode* m = NULL;
419 assert(req() == 3, "same as region");
420 Node* r = in(0);
421 for (uint i = 1; i < 3; ++i) {
422 Node *mem = in(i);
423 if (mem && mem->is_MergeMem() && r->in(i)->outcnt() == 1) {
424 // Nothing is control-dependent on path #i except the region itself.
425 m = mem->as_MergeMem();
426 uint j = 3 - i;
427 Node* other = in(j);
428 if (other && other == m->base_memory()) {
429 // m is a successor memory to other, and is not pinned inside the diamond, so push it out.
430 // This will allow the diamond to collapse completely.
431 return m;
432 }
433 }
434 }
435 }
436 return NULL;
437 }
438
439 //------------------------------Ideal------------------------------------------
440 // Return a node which is more "ideal" than the current node. Must preserve
441 // the CFG, but we can still strip out dead paths.
442 Node *RegionNode::Ideal(PhaseGVN *phase, bool can_reshape) {
443 if( !can_reshape && !in(0) ) return NULL; // Already degraded to a Copy
444 assert(!in(0) || !in(0)->is_Root(), "not a specially hidden merge");
445
446 // Check for RegionNode with no Phi users and both inputs come from either
447 // arm of the same IF. If found, then the control-flow split is useless.
448 bool has_phis = false;
449 if (can_reshape) { // Need DU info to check for Phi users
450 has_phis = (has_phi() != NULL); // Cache result
451 if (has_phis) {
452 PhiNode* phi = has_unique_phi();
453 if (phi != NULL) {
454 Node* m = phi->try_clean_mem_phi(phase);
455 if (m != NULL) {
456 phase->is_IterGVN()->replace_node(phi, m);
457 has_phis = false;
458 }
459 }
460 }
461
462 if (!has_phis) { // No Phi users? Nothing merging?
463 for (uint i = 1; i < req()-1; i++) {
464 Node *if1 = in(i);
465 if( !if1 ) continue;
466 Node *iff = if1->in(0);
467 if( !iff || !iff->is_If() ) continue;
468 for( uint j=i+1; j<req(); j++ ) {
469 if( in(j) && in(j)->in(0) == iff &&
470 if1->Opcode() != in(j)->Opcode() ) {
471 // Add the IF Projections to the worklist. They (and the IF itself)
472 // will be eliminated if dead.
473 phase->is_IterGVN()->add_users_to_worklist(iff);
474 set_req(i, iff->in(0));// Skip around the useless IF diamond
475 set_req(j, NULL);
476 return this; // Record progress
477 }
478 }
479 }
480 }
481 }
482
483 // Remove TOP or NULL input paths. If only 1 input path remains, this Region
484 // degrades to a copy.
485 bool add_to_worklist = true;
486 bool modified = false;
487 int cnt = 0; // Count of values merging
488 DEBUG_ONLY( int cnt_orig = req(); ) // Save original inputs count
489 int del_it = 0; // The last input path we delete
490 // For all inputs...
491 for( uint i=1; i<req(); ++i ){// For all paths in
492 Node *n = in(i); // Get the input
493 if( n != NULL ) {
494 // Remove useless control copy inputs
495 if( n->is_Region() && n->as_Region()->is_copy() ) {
496 set_req(i, n->nonnull_req());
497 modified = true;
498 i--;
499 continue;
500 }
501 if( n->is_Proj() ) { // Remove useless rethrows
502 Node *call = n->in(0);
503 if (call->is_Call() && call->as_Call()->entry_point() == OptoRuntime::rethrow_stub()) {
504 set_req(i, call->in(0));
505 modified = true;
506 i--;
507 continue;
508 }
509 }
510 if( phase->type(n) == Type::TOP ) {
511 set_req_X(i, NULL, phase); // Ignore TOP inputs
512 modified = true;
513 i--;
514 continue;
515 }
516 cnt++; // One more value merging
517
518 } else if (can_reshape) { // Else found dead path with DU info
519 PhaseIterGVN *igvn = phase->is_IterGVN();
520 del_req(i); // Yank path from self
521 del_it = i;
522 uint max = outcnt();
523 DUIterator j;
524 bool progress = true;
525 while(progress) { // Need to establish property over all users
526 progress = false;
527 for (j = outs(); has_out(j); j++) {
528 Node *n = out(j);
529 if( n->req() != req() && n->is_Phi() ) {
530 assert( n->in(0) == this, "" );
531 igvn->hash_delete(n); // Yank from hash before hacking edges
532 n->set_req_X(i,NULL,igvn);// Correct DU info
533 n->del_req(i); // Yank path from Phis
534 if( max != outcnt() ) {
535 progress = true;
536 j = refresh_out_pos(j);
537 max = outcnt();
538 }
539 }
540 }
541 }
542 add_to_worklist = false;
543 phase->is_IterGVN()->add_users_to_worklist(this);
544 i--;
545 }
546 }
547
548 if (can_reshape && cnt == 1) {
549 // Is it dead loop?
550 // If it is LoopNopde it had 2 (+1 itself) inputs and
551 // one of them was cut. The loop is dead if it was EntryContol.
552 // Loop node may have only one input because entry path
553 // is removed in PhaseIdealLoop::Dominators().
554 assert(!this->is_Loop() || cnt_orig <= 3, "Loop node should have 3 or less inputs");
555 if ((this->is_Loop() && (del_it == LoopNode::EntryControl ||
556 (del_it == 0 && is_unreachable_region(phase)))) ||
557 (!this->is_Loop() && has_phis && is_unreachable_region(phase))) {
558 // This region and therefore all nodes on the input control path(s) are unreachable
559 // from root. To avoid incomplete removal of unreachable subgraphs, walk up the CFG
560 // and aggressively replace all nodes by top.
561 PhaseIterGVN* igvn = phase->is_IterGVN();
562 Node* top = phase->C->top();
563 ResourceMark rm;
564 Node_List nstack;
565 VectorSet visited;
566 nstack.push(this);
567 visited.set(_idx);
568 while (nstack.size() != 0) {
569 Node* n = nstack.pop();
570 for (uint i = 0; i < n->req(); ++i) {
571 Node* m = n->in(i);
572 assert(m != (Node*)phase->C->root(), "Should be unreachable from root");
573 if (m != NULL && m->is_CFG() && !visited.test_set(m->_idx)) {
574 nstack.push(m);
575 }
576 }
577 if (n->is_Region()) {
578 // Eagerly replace phis with top to avoid regionless phis.
579 n->set_req(0, NULL);
580 bool progress = true;
581 uint max = n->outcnt();
582 DUIterator j;
583 while (progress) {
584 progress = false;
585 for (j = n->outs(); n->has_out(j); j++) {
586 Node* u = n->out(j);
587 if (u->is_Phi()) {
588 igvn->replace_node(u, top);
589 if (max != n->outcnt()) {
590 progress = true;
591 j = n->refresh_out_pos(j);
592 max = n->outcnt();
593 }
594 }
595 }
596 }
597 }
598 igvn->replace_node(n, top);
599 }
600 return NULL;
601 }
602 }
603
604 if( cnt <= 1 ) { // Only 1 path in?
605 set_req(0, NULL); // Null control input for region copy
606 if( cnt == 0 && !can_reshape) { // Parse phase - leave the node as it is.
607 // No inputs or all inputs are NULL.
608 return NULL;
609 } else if (can_reshape) { // Optimization phase - remove the node
610 PhaseIterGVN *igvn = phase->is_IterGVN();
611 // Strip mined (inner) loop is going away, remove outer loop.
612 if (is_CountedLoop() &&
613 as_Loop()->is_strip_mined()) {
614 Node* outer_sfpt = as_CountedLoop()->outer_safepoint();
615 Node* outer_out = as_CountedLoop()->outer_loop_exit();
616 if (outer_sfpt != NULL && outer_out != NULL) {
617 Node* in = outer_sfpt->in(0);
618 igvn->replace_node(outer_out, in);
619 LoopNode* outer = as_CountedLoop()->outer_loop();
620 igvn->replace_input_of(outer, LoopNode::LoopBackControl, igvn->C->top());
621 }
622 }
623 if (is_CountedLoop()) {
624 Node* opaq = as_CountedLoop()->is_canonical_loop_entry();
625 if (opaq != NULL) {
626 // This is not a loop anymore. No need to keep the Opaque1 node on the test that guards the loop as it won't be
627 // subject to further loop opts.
628 assert(opaq->Opcode() == Op_Opaque1, "");
629 igvn->replace_node(opaq, opaq->in(1));
630 }
631 }
632 Node *parent_ctrl;
633 if( cnt == 0 ) {
634 assert( req() == 1, "no inputs expected" );
635 // During IGVN phase such region will be subsumed by TOP node
636 // so region's phis will have TOP as control node.
637 // Kill phis here to avoid it.
638 // Also set other user's input to top.
639 parent_ctrl = phase->C->top();
640 } else {
641 // The fallthrough case since we already checked dead loops above.
642 parent_ctrl = in(1);
643 assert(parent_ctrl != NULL, "Region is a copy of some non-null control");
644 assert(parent_ctrl != this, "Close dead loop");
645 }
646 if (add_to_worklist) {
647 igvn->add_users_to_worklist(this); // Check for further allowed opts
648 }
649 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) {
650 Node* n = last_out(i);
651 igvn->hash_delete(n); // Remove from worklist before modifying edges
652 if (n->outcnt() == 0) {
653 int uses_found = n->replace_edge(this, phase->C->top(), igvn);
654 if (uses_found > 1) { // (--i) done at the end of the loop.
655 i -= (uses_found - 1);
656 }
657 continue;
658 }
659 if( n->is_Phi() ) { // Collapse all Phis
660 // Eagerly replace phis to avoid regionless phis.
661 Node* in;
662 if( cnt == 0 ) {
663 assert( n->req() == 1, "No data inputs expected" );
664 in = parent_ctrl; // replaced by top
665 } else {
666 assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" );
667 in = n->in(1); // replaced by unique input
668 if( n->as_Phi()->is_unsafe_data_reference(in) )
669 in = phase->C->top(); // replaced by top
670 }
671 igvn->replace_node(n, in);
672 }
673 else if( n->is_Region() ) { // Update all incoming edges
674 assert(n != this, "Must be removed from DefUse edges");
675 int uses_found = n->replace_edge(this, parent_ctrl, igvn);
676 if (uses_found > 1) { // (--i) done at the end of the loop.
677 i -= (uses_found - 1);
678 }
679 }
680 else {
681 assert(n->in(0) == this, "Expect RegionNode to be control parent");
682 n->set_req(0, parent_ctrl);
683 }
684 #ifdef ASSERT
685 for( uint k=0; k < n->req(); k++ ) {
686 assert(n->in(k) != this, "All uses of RegionNode should be gone");
687 }
688 #endif
689 }
690 // Remove the RegionNode itself from DefUse info
691 igvn->remove_dead_node(this);
692 return NULL;
693 }
694 return this; // Record progress
695 }
696
697
698 // If a Region flows into a Region, merge into one big happy merge.
699 if (can_reshape) {
700 Node *m = merge_region(this, phase);
701 if (m != NULL) return m;
702 }
703
704 // Check if this region is the root of a clipping idiom on floats
705 if( ConvertFloat2IntClipping && can_reshape && req() == 4 ) {
706 // Check that only one use is a Phi and that it simplifies to two constants +
707 PhiNode* phi = has_unique_phi();
708 if (phi != NULL) { // One Phi user
709 // Check inputs to the Phi
710 ConNode *min;
711 ConNode *max;
712 Node *val;
713 uint min_idx;
714 uint max_idx;
715 uint val_idx;
716 if( check_phi_clipping( phi, min, min_idx, max, max_idx, val, val_idx ) ) {
717 IfNode *top_if;
718 IfNode *bot_if;
719 if( check_if_clipping( this, bot_if, top_if ) ) {
720 // Control pattern checks, now verify compares
721 Node *top_in = NULL; // value being compared against
722 Node *bot_in = NULL;
723 if( check_compare_clipping( true, bot_if, min, bot_in ) &&
724 check_compare_clipping( false, top_if, max, top_in ) ) {
725 if( bot_in == top_in ) {
726 PhaseIterGVN *gvn = phase->is_IterGVN();
727 assert( gvn != NULL, "Only had DefUse info in IterGVN");
728 // Only remaining check is that bot_in == top_in == (Phi's val + mods)
729
730 // Check for the ConvF2INode
731 ConvF2INode *convf2i;
732 if( check_convf2i_clipping( phi, val_idx, convf2i, min, max ) &&
733 convf2i->in(1) == bot_in ) {
734 // Matched pattern, including LShiftI; RShiftI, replace with integer compares
735 // max test
736 Node *cmp = gvn->register_new_node_with_optimizer(new CmpINode( convf2i, min ));
737 Node *boo = gvn->register_new_node_with_optimizer(new BoolNode( cmp, BoolTest::lt ));
738 IfNode *iff = (IfNode*)gvn->register_new_node_with_optimizer(new IfNode( top_if->in(0), boo, PROB_UNLIKELY_MAG(5), top_if->_fcnt ));
739 Node *if_min= gvn->register_new_node_with_optimizer(new IfTrueNode (iff));
740 Node *ifF = gvn->register_new_node_with_optimizer(new IfFalseNode(iff));
741 // min test
742 cmp = gvn->register_new_node_with_optimizer(new CmpINode( convf2i, max ));
743 boo = gvn->register_new_node_with_optimizer(new BoolNode( cmp, BoolTest::gt ));
744 iff = (IfNode*)gvn->register_new_node_with_optimizer(new IfNode( ifF, boo, PROB_UNLIKELY_MAG(5), bot_if->_fcnt ));
745 Node *if_max= gvn->register_new_node_with_optimizer(new IfTrueNode (iff));
746 ifF = gvn->register_new_node_with_optimizer(new IfFalseNode(iff));
747 // update input edges to region node
748 set_req_X( min_idx, if_min, gvn );
749 set_req_X( max_idx, if_max, gvn );
750 set_req_X( val_idx, ifF, gvn );
751 // remove unnecessary 'LShiftI; RShiftI' idiom
752 gvn->hash_delete(phi);
753 phi->set_req_X( val_idx, convf2i, gvn );
754 gvn->hash_find_insert(phi);
755 // Return transformed region node
756 return this;
757 }
758 }
759 }
760 }
761 }
762 }
763 }
764
765 if (can_reshape) {
766 modified |= optimize_trichotomy(phase->is_IterGVN());
767 }
768
769 return modified ? this : NULL;
770 }
771
772 //------------------------------optimize_trichotomy--------------------------
773 // Optimize nested comparisons of the following kind:
774 //
775 // int compare(int a, int b) {
776 // return (a < b) ? -1 : (a == b) ? 0 : 1;
777 // }
778 //
779 // Shape 1:
780 // if (compare(a, b) == 1) { ... } -> if (a > b) { ... }
781 //
782 // Shape 2:
783 // if (compare(a, b) == 0) { ... } -> if (a == b) { ... }
784 //
785 // Above code leads to the following IR shapes where both Ifs compare the
786 // same value and two out of three region inputs idx1 and idx2 map to
787 // the same value and control flow.
788 //
789 // (1) If (2) If
790 // / \ / \
791 // Proj Proj Proj Proj
792 // | \ | \
793 // | If | If If
794 // | / \ | / \ / \
795 // | Proj Proj | Proj Proj ==> Proj Proj
796 // | / / \ | / | /
797 // Region / \ | / | /
798 // \ / \ | / | /
799 // Region Region Region
800 //
801 // The method returns true if 'this' is modified and false otherwise.
802 bool RegionNode::optimize_trichotomy(PhaseIterGVN* igvn) {
803 int idx1 = 1, idx2 = 2;
804 Node* region = NULL;
805 if (req() == 3 && in(1) != NULL && in(2) != NULL) {
806 // Shape 1: Check if one of the inputs is a region that merges two control
807 // inputs and has no other users (especially no Phi users).
808 region = in(1)->isa_Region() ? in(1) : in(2)->isa_Region();
809 if (region == NULL || region->outcnt() != 2 || region->req() != 3) {
810 return false; // No suitable region input found
811 }
812 } else if (req() == 4) {
813 // Shape 2: Check if two control inputs map to the same value of the unique phi
814 // user and treat these as if they would come from another region (shape (1)).
815 PhiNode* phi = has_unique_phi();
816 if (phi == NULL) {
817 return false; // No unique phi user
818 }
819 if (phi->in(idx1) != phi->in(idx2)) {
820 idx2 = 3;
821 if (phi->in(idx1) != phi->in(idx2)) {
822 idx1 = 2;
823 if (phi->in(idx1) != phi->in(idx2)) {
824 return false; // No equal phi inputs found
825 }
826 }
827 }
828 assert(phi->in(idx1) == phi->in(idx2), "must be"); // Region is merging same value
829 region = this;
830 }
831 if (region == NULL || region->in(idx1) == NULL || region->in(idx2) == NULL) {
832 return false; // Region does not merge two control inputs
833 }
834 // At this point we know that region->in(idx1) and region->(idx2) map to the same
835 // value and control flow. Now search for ifs that feed into these region inputs.
836 ProjNode* proj1 = region->in(idx1)->isa_Proj();
837 ProjNode* proj2 = region->in(idx2)->isa_Proj();
838 if (proj1 == NULL || proj1->outcnt() != 1 ||
839 proj2 == NULL || proj2->outcnt() != 1) {
840 return false; // No projection inputs with region as unique user found
841 }
842 assert(proj1 != proj2, "should be different projections");
843 IfNode* iff1 = proj1->in(0)->isa_If();
844 IfNode* iff2 = proj2->in(0)->isa_If();
845 if (iff1 == NULL || iff1->outcnt() != 2 ||
846 iff2 == NULL || iff2->outcnt() != 2) {
847 return false; // No ifs found
848 }
849 if (iff1 == iff2) {
850 igvn->add_users_to_worklist(iff1); // Make sure dead if is eliminated
851 igvn->replace_input_of(region, idx1, iff1->in(0));
852 igvn->replace_input_of(region, idx2, igvn->C->top());
853 return (region == this); // Remove useless if (both projections map to the same control/value)
854 }
855 BoolNode* bol1 = iff1->in(1)->isa_Bool();
856 BoolNode* bol2 = iff2->in(1)->isa_Bool();
857 if (bol1 == NULL || bol2 == NULL) {
858 return false; // No bool inputs found
859 }
860 Node* cmp1 = bol1->in(1);
861 Node* cmp2 = bol2->in(1);
862 bool commute = false;
863 if (!cmp1->is_Cmp() || !cmp2->is_Cmp()) {
864 return false; // No comparison
865 } else if (cmp1->Opcode() == Op_CmpF || cmp1->Opcode() == Op_CmpD ||
866 cmp2->Opcode() == Op_CmpF || cmp2->Opcode() == Op_CmpD ||
867 cmp1->Opcode() == Op_CmpP || cmp1->Opcode() == Op_CmpN ||
868 cmp2->Opcode() == Op_CmpP || cmp2->Opcode() == Op_CmpN ||
869 cmp1->is_SubTypeCheck() || cmp2->is_SubTypeCheck() ||
870 cmp1->is_FlatArrayCheck() || cmp2->is_FlatArrayCheck()) {
871 // Floats and pointers don't exactly obey trichotomy. To be on the safe side, don't transform their tests.
872 // SubTypeCheck is not commutative
873 return false;
874 } else if (cmp1 != cmp2) {
875 if (cmp1->in(1) == cmp2->in(2) &&
876 cmp1->in(2) == cmp2->in(1)) {
877 commute = true; // Same but swapped inputs, commute the test
878 } else {
879 return false; // Ifs are not comparing the same values
880 }
881 }
882 proj1 = proj1->other_if_proj();
883 proj2 = proj2->other_if_proj();
884 if (!((proj1->unique_ctrl_out_or_null() == iff2 &&
885 proj2->unique_ctrl_out_or_null() == this) ||
886 (proj2->unique_ctrl_out_or_null() == iff1 &&
887 proj1->unique_ctrl_out_or_null() == this))) {
888 return false; // Ifs are not connected through other projs
889 }
890 // Found 'iff -> proj -> iff -> proj -> this' shape where all other projs are merged
891 // through 'region' and map to the same value. Merge the boolean tests and replace
892 // the ifs by a single comparison.
893 BoolTest test1 = (proj1->_con == 1) ? bol1->_test : bol1->_test.negate();
894 BoolTest test2 = (proj2->_con == 1) ? bol2->_test : bol2->_test.negate();
895 test1 = commute ? test1.commute() : test1;
896 // After possibly commuting test1, if we can merge test1 & test2, then proj2/iff2/bol2 are the nodes to refine.
897 BoolTest::mask res = test1.merge(test2);
898 if (res == BoolTest::illegal) {
899 return false; // Unable to merge tests
900 }
901 // Adjust iff1 to always pass (only iff2 will remain)
902 igvn->replace_input_of(iff1, 1, igvn->intcon(proj1->_con));
903 if (res == BoolTest::never) {
904 // Merged test is always false, adjust iff2 to always fail
905 igvn->replace_input_of(iff2, 1, igvn->intcon(1 - proj2->_con));
906 } else {
907 // Replace bool input of iff2 with merged test
908 BoolNode* new_bol = new BoolNode(bol2->in(1), res);
909 igvn->replace_input_of(iff2, 1, igvn->transform((proj2->_con == 1) ? new_bol : new_bol->negate(igvn)));
910 if (new_bol->outcnt() == 0) {
911 igvn->remove_dead_node(new_bol);
912 }
913 }
914 return false;
915 }
916
917 const RegMask &RegionNode::out_RegMask() const {
918 return RegMask::Empty;
919 }
920
921 // Find the one non-null required input. RegionNode only
922 Node *Node::nonnull_req() const {
923 assert( is_Region(), "" );
924 for( uint i = 1; i < _cnt; i++ )
925 if( in(i) )
926 return in(i);
927 ShouldNotReachHere();
928 return NULL;
929 }
930
931
932 //=============================================================================
933 // note that these functions assume that the _adr_type field is flattened
934 uint PhiNode::hash() const {
935 const Type* at = _adr_type;
936 return TypeNode::hash() + (at ? at->hash() : 0);
937 }
938 bool PhiNode::cmp( const Node &n ) const {
939 return TypeNode::cmp(n) && _adr_type == ((PhiNode&)n)._adr_type;
940 }
941 static inline
942 const TypePtr* flatten_phi_adr_type(const TypePtr* at) {
943 if (at == NULL || at == TypePtr::BOTTOM) return at;
944 return Compile::current()->alias_type(at)->adr_type();
945 }
946
947 //----------------------------make---------------------------------------------
948 // create a new phi with edges matching r and set (initially) to x
949 PhiNode* PhiNode::make(Node* r, Node* x, const Type *t, const TypePtr* at) {
950 uint preds = r->req(); // Number of predecessor paths
951 assert(t != Type::MEMORY || at == flatten_phi_adr_type(at) || (flatten_phi_adr_type(at) == TypeAryPtr::INLINES && Compile::current()->flattened_accesses_share_alias()), "flatten at");
952 PhiNode* p = new PhiNode(r, t, at);
953 for (uint j = 1; j < preds; j++) {
954 // Fill in all inputs, except those which the region does not yet have
955 if (r->in(j) != NULL)
956 p->init_req(j, x);
957 }
958 return p;
959 }
960 PhiNode* PhiNode::make(Node* r, Node* x) {
961 const Type* t = x->bottom_type();
962 const TypePtr* at = NULL;
963 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type());
964 return make(r, x, t, at);
965 }
966 PhiNode* PhiNode::make_blank(Node* r, Node* x) {
967 const Type* t = x->bottom_type();
968 const TypePtr* at = NULL;
969 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type());
970 return new PhiNode(r, t, at);
971 }
972
973
974 //------------------------slice_memory-----------------------------------------
975 // create a new phi with narrowed memory type
976 PhiNode* PhiNode::slice_memory(const TypePtr* adr_type) const {
977 PhiNode* mem = (PhiNode*) clone();
978 *(const TypePtr**)&mem->_adr_type = adr_type;
979 // convert self-loops, or else we get a bad graph
980 for (uint i = 1; i < req(); i++) {
981 if ((const Node*)in(i) == this) mem->set_req(i, mem);
982 }
983 mem->verify_adr_type();
984 return mem;
985 }
986
987 //------------------------split_out_instance-----------------------------------
988 // Split out an instance type from a bottom phi.
989 PhiNode* PhiNode::split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const {
990 const TypeOopPtr *t_oop = at->isa_oopptr();
991 assert(t_oop != NULL && t_oop->is_known_instance(), "expecting instance oopptr");
992 const TypePtr *t = adr_type();
993 assert(type() == Type::MEMORY &&
994 (t == TypePtr::BOTTOM || t == TypeRawPtr::BOTTOM ||
995 t->isa_oopptr() && !t->is_oopptr()->is_known_instance() &&
996 t->is_oopptr()->cast_to_exactness(true)
997 ->is_oopptr()->cast_to_ptr_type(t_oop->ptr())
998 ->is_oopptr()->cast_to_instance_id(t_oop->instance_id()) == t_oop),
999 "bottom or raw memory required");
1000
1001 // Check if an appropriate node already exists.
1002 Node *region = in(0);
1003 for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) {
1004 Node* use = region->fast_out(k);
1005 if( use->is_Phi()) {
1006 PhiNode *phi2 = use->as_Phi();
1007 if (phi2->type() == Type::MEMORY && phi2->adr_type() == at) {
1008 return phi2;
1009 }
1010 }
1011 }
1012 Compile *C = igvn->C;
1013 Arena *a = Thread::current()->resource_area();
1014 Node_Array node_map = new Node_Array(a);
1015 Node_Stack stack(a, C->live_nodes() >> 4);
1016 PhiNode *nphi = slice_memory(at);
1017 igvn->register_new_node_with_optimizer( nphi );
1018 node_map.map(_idx, nphi);
1019 stack.push((Node *)this, 1);
1020 while(!stack.is_empty()) {
1021 PhiNode *ophi = stack.node()->as_Phi();
1022 uint i = stack.index();
1023 assert(i >= 1, "not control edge");
1024 stack.pop();
1025 nphi = node_map[ophi->_idx]->as_Phi();
1026 for (; i < ophi->req(); i++) {
1027 Node *in = ophi->in(i);
1028 if (in == NULL || igvn->type(in) == Type::TOP)
1029 continue;
1030 Node *opt = MemNode::optimize_simple_memory_chain(in, t_oop, NULL, igvn);
1031 PhiNode *optphi = opt->is_Phi() ? opt->as_Phi() : NULL;
1032 if (optphi != NULL && optphi->adr_type() == TypePtr::BOTTOM) {
1033 opt = node_map[optphi->_idx];
1034 if (opt == NULL) {
1035 stack.push(ophi, i);
1036 nphi = optphi->slice_memory(at);
1037 igvn->register_new_node_with_optimizer( nphi );
1038 node_map.map(optphi->_idx, nphi);
1039 ophi = optphi;
1040 i = 0; // will get incremented at top of loop
1041 continue;
1042 }
1043 }
1044 nphi->set_req(i, opt);
1045 }
1046 }
1047 return nphi;
1048 }
1049
1050 //------------------------verify_adr_type--------------------------------------
1051 #ifdef ASSERT
1052 void PhiNode::verify_adr_type(VectorSet& visited, const TypePtr* at) const {
1053 if (visited.test_set(_idx)) return; //already visited
1054
1055 // recheck constructor invariants:
1056 verify_adr_type(false);
1057
1058 // recheck local phi/phi consistency:
1059 assert(_adr_type == at || _adr_type == TypePtr::BOTTOM,
1060 "adr_type must be consistent across phi nest");
1061
1062 // walk around
1063 for (uint i = 1; i < req(); i++) {
1064 Node* n = in(i);
1065 if (n == NULL) continue;
1066 const Node* np = in(i);
1067 if (np->is_Phi()) {
1068 np->as_Phi()->verify_adr_type(visited, at);
1069 } else if (n->bottom_type() == Type::TOP
1070 || (n->is_Mem() && n->in(MemNode::Address)->bottom_type() == Type::TOP)) {
1071 // ignore top inputs
1072 } else {
1073 const TypePtr* nat = flatten_phi_adr_type(n->adr_type());
1074 // recheck phi/non-phi consistency at leaves:
1075 assert((nat != NULL) == (at != NULL), "");
1076 assert(nat == at || nat == TypePtr::BOTTOM,
1077 "adr_type must be consistent at leaves of phi nest");
1078 }
1079 }
1080 }
1081
1082 // Verify a whole nest of phis rooted at this one.
1083 void PhiNode::verify_adr_type(bool recursive) const {
1084 if (VMError::is_error_reported()) return; // muzzle asserts when debugging an error
1085 if (Node::in_dump()) return; // muzzle asserts when printing
1086
1087 assert((_type == Type::MEMORY) == (_adr_type != NULL), "adr_type for memory phis only");
1088 // Flat array element shouldn't get their own memory slice until flattened_accesses_share_alias is cleared.
1089 // It could be the graph has no loads/stores and flattened_accesses_share_alias is never cleared. EA could still
1090 // creates per element Phis but that wouldn't be a problem as there are no memory accesses for that array.
1091 assert(_adr_type == NULL || _adr_type->isa_aryptr() == NULL ||
1092 _adr_type->is_aryptr()->is_known_instance() ||
1093 !_adr_type->is_aryptr()->is_flat() ||
1094 !Compile::current()->flattened_accesses_share_alias() ||
1095 _adr_type == TypeAryPtr::INLINES, "flat array element shouldn't get its own slice yet");
1096
1097 if (!VerifyAliases) return; // verify thoroughly only if requested
1098
1099 assert(_adr_type == flatten_phi_adr_type(_adr_type),
1100 "Phi::adr_type must be pre-normalized");
1101
1102 if (recursive) {
1103 VectorSet visited;
1104 verify_adr_type(visited, _adr_type);
1105 }
1106 }
1107 #endif
1108
1109
1110 //------------------------------Value------------------------------------------
1111 // Compute the type of the PhiNode
1112 const Type* PhiNode::Value(PhaseGVN* phase) const {
1113 Node *r = in(0); // RegionNode
1114 if( !r ) // Copy or dead
1115 return in(1) ? phase->type(in(1)) : Type::TOP;
1116
1117 // Note: During parsing, phis are often transformed before their regions.
1118 // This means we have to use type_or_null to defend against untyped regions.
1119 if( phase->type_or_null(r) == Type::TOP ) // Dead code?
1120 return Type::TOP;
1121
1122 // Check for trip-counted loop. If so, be smarter.
1123 BaseCountedLoopNode* l = r->is_BaseCountedLoop() ? r->as_BaseCountedLoop() : NULL;
1124 if (l && ((const Node*)l->phi() == this)) { // Trip counted loop!
1125 // protect against init_trip() or limit() returning NULL
1126 if (l->can_be_counted_loop(phase)) {
1127 const Node* init = l->init_trip();
1128 const Node* limit = l->limit();
1129 const Node* stride = l->stride();
1130 if (init != NULL && limit != NULL && stride != NULL) {
1131 const TypeInteger* lo = phase->type(init)->isa_integer(l->bt());
1132 const TypeInteger* hi = phase->type(limit)->isa_integer(l->bt());
1133 const TypeInteger* stride_t = phase->type(stride)->isa_integer(l->bt());
1134 if (lo != NULL && hi != NULL && stride_t != NULL) { // Dying loops might have TOP here
1135 assert(stride_t->is_con(), "bad stride type");
1136 BoolTest::mask bt = l->loopexit()->test_trip();
1137 // If the loop exit condition is "not equal", the condition
1138 // would not trigger if init > limit (if stride > 0) or if
1139 // init < limit if (stride > 0) so we can't deduce bounds
1140 // for the iv from the exit condition.
1141 if (bt != BoolTest::ne) {
1142 jlong stride_con = stride_t->get_con_as_long(l->bt());
1143 if (stride_con < 0) { // Down-counter loop
1144 swap(lo, hi);
1145 jlong iv_range_lower_limit = lo->lo_as_long();
1146 // Prevent overflow when adding one below
1147 if (iv_range_lower_limit < max_signed_integer(l->bt())) {
1148 // The loop exit condition is: iv + stride > limit (iv is this Phi). So the loop iterates until
1149 // iv + stride <= limit
1150 // We know that: limit >= lo->lo_as_long() and stride <= -1
1151 // So when the loop exits, iv has to be at most lo->lo_as_long() + 1
1152 iv_range_lower_limit += 1; // lo is after decrement
1153 // Exact bounds for the phi can be computed when ABS(stride) greater than 1 if bounds are constant.
1154 if (lo->is_con() && hi->is_con() && hi->lo_as_long() > lo->hi_as_long() && stride_con != -1) {
1155 julong uhi = static_cast<julong>(hi->lo_as_long());
1156 julong ulo = static_cast<julong>(lo->hi_as_long());
1157 julong diff = ((uhi - ulo - 1) / (-stride_con)) * (-stride_con);
1158 julong ufirst = hi->lo_as_long() - diff;
1159 iv_range_lower_limit = reinterpret_cast<jlong &>(ufirst);
1160 assert(iv_range_lower_limit >= lo->lo_as_long() + 1, "should end up with narrower range");
1161 }
1162 }
1163 return TypeInteger::make(MIN2(iv_range_lower_limit, hi->lo_as_long()), hi->hi_as_long(), 3, l->bt())->filter_speculative(_type);
1164 } else if (stride_con >= 0) {
1165 jlong iv_range_upper_limit = hi->hi_as_long();
1166 // Prevent overflow when subtracting one below
1167 if (iv_range_upper_limit > min_signed_integer(l->bt())) {
1168 // The loop exit condition is: iv + stride < limit (iv is this Phi). So the loop iterates until
1169 // iv + stride >= limit
1170 // We know that: limit <= hi->hi_as_long() and stride >= 1
1171 // So when the loop exits, iv has to be at most hi->hi_as_long() - 1
1172 iv_range_upper_limit -= 1;
1173 // Exact bounds for the phi can be computed when ABS(stride) greater than 1 if bounds are constant.
1174 if (lo->is_con() && hi->is_con() && hi->lo_as_long() > lo->hi_as_long() && stride_con != 1) {
1175 julong uhi = static_cast<julong>(hi->lo_as_long());
1176 julong ulo = static_cast<julong>(lo->hi_as_long());
1177 julong diff = ((uhi - ulo - 1) / stride_con) * stride_con;
1178 julong ulast = lo->hi_as_long() + diff;
1179 iv_range_upper_limit = reinterpret_cast<jlong &>(ulast);
1180 assert(iv_range_upper_limit <= hi->hi_as_long() - 1, "should end up with narrower range");
1181 }
1182 }
1183 return TypeInteger::make(lo->lo_as_long(), MAX2(lo->hi_as_long(), iv_range_upper_limit), 3, l->bt())->filter_speculative(_type);
1184 }
1185 }
1186 }
1187 }
1188 } else if (l->in(LoopNode::LoopBackControl) != NULL &&
1189 in(LoopNode::EntryControl) != NULL &&
1190 phase->type(l->in(LoopNode::LoopBackControl)) == Type::TOP) {
1191 // During CCP, if we saturate the type of a counted loop's Phi
1192 // before the special code for counted loop above has a chance
1193 // to run (that is as long as the type of the backedge's control
1194 // is top), we might end up with non monotonic types
1195 return phase->type(in(LoopNode::EntryControl))->filter_speculative(_type);
1196 }
1197 }
1198
1199 // Until we have harmony between classes and interfaces in the type
1200 // lattice, we must tread carefully around phis which implicitly
1201 // convert the one to the other.
1202 const TypePtr* ttp = _type->make_ptr();
1203 const TypeInstPtr* ttip = (ttp != NULL) ? ttp->isa_instptr() : NULL;
1204 const TypeInstKlassPtr* ttkp = (ttp != NULL) ? ttp->isa_instklassptr() : NULL;
1205 bool is_intf = false;
1206 if (ttip != NULL) {
1207 if (ttip->is_interface())
1208 is_intf = true;
1209 }
1210 if (ttkp != NULL) {
1211 if (ttkp->is_interface())
1212 is_intf = true;
1213 }
1214
1215 // Default case: merge all inputs
1216 const Type *t = Type::TOP; // Merged type starting value
1217 for (uint i = 1; i < req(); ++i) {// For all paths in
1218 // Reachable control path?
1219 if (r->in(i) && phase->type(r->in(i)) == Type::CONTROL) {
1220 const Type* ti = phase->type(in(i));
1221 // We assume that each input of an interface-valued Phi is a true
1222 // subtype of that interface. This might not be true of the meet
1223 // of all the input types. The lattice is not distributive in
1224 // such cases. Ward off asserts in type.cpp by refusing to do
1225 // meets between interfaces and proper classes.
1226 const TypePtr* tip = ti->make_ptr();
1227 const TypeInstPtr* tiip = (tip != NULL) ? tip->isa_instptr() : NULL;
1228 if (tiip) {
1229 bool ti_is_intf = false;
1230 if (tiip->is_interface())
1231 ti_is_intf = true;
1232 if (is_intf != ti_is_intf)
1233 { t = _type; break; }
1234 }
1235 t = t->meet_speculative(ti);
1236 }
1237 }
1238
1239 // The worst-case type (from ciTypeFlow) should be consistent with "t".
1240 // That is, we expect that "t->higher_equal(_type)" holds true.
1241 // There are various exceptions:
1242 // - Inputs which are phis might in fact be widened unnecessarily.
1243 // For example, an input might be a widened int while the phi is a short.
1244 // - Inputs might be BotPtrs but this phi is dependent on a null check,
1245 // and postCCP has removed the cast which encodes the result of the check.
1246 // - The type of this phi is an interface, and the inputs are classes.
1247 // - Value calls on inputs might produce fuzzy results.
1248 // (Occurrences of this case suggest improvements to Value methods.)
1249 //
1250 // It is not possible to see Type::BOTTOM values as phi inputs,
1251 // because the ciTypeFlow pre-pass produces verifier-quality types.
1252 const Type* ft = t->filter_speculative(_type); // Worst case type
1253
1254 #ifdef ASSERT
1255 // The following logic has been moved into TypeOopPtr::filter.
1256 const Type* jt = t->join_speculative(_type);
1257 if (jt->empty()) { // Emptied out???
1258
1259 // Check for evil case of 't' being a class and '_type' expecting an
1260 // interface. This can happen because the bytecodes do not contain
1261 // enough type info to distinguish a Java-level interface variable
1262 // from a Java-level object variable. If we meet 2 classes which
1263 // both implement interface I, but their meet is at 'j/l/O' which
1264 // doesn't implement I, we have no way to tell if the result should
1265 // be 'I' or 'j/l/O'. Thus we'll pick 'j/l/O'. If this then flows
1266 // into a Phi which "knows" it's an Interface type we'll have to
1267 // uplift the type.
1268 if (!t->empty() && ttip && ttip->is_interface()) {
1269 assert(ft == _type, ""); // Uplift to interface
1270 } else if (!t->empty() && ttkp && ttkp->is_interface()) {
1271 assert(ft == _type, ""); // Uplift to interface
1272 } else {
1273 // We also have to handle 'evil cases' of interface- vs. class-arrays
1274 Type::get_arrays_base_elements(jt, _type, NULL, &ttip);
1275 if (!t->empty() && ttip != NULL && ttip->is_interface()) {
1276 assert(ft == _type, ""); // Uplift to array of interface
1277 } else {
1278 // Otherwise it's something stupid like non-overlapping int ranges
1279 // found on dying counted loops.
1280 assert(ft == Type::TOP, ""); // Canonical empty value
1281 }
1282 }
1283 }
1284
1285 else {
1286
1287 // If we have an interface-typed Phi and we narrow to a class type, the join
1288 // should report back the class. However, if we have a J/L/Object
1289 // class-typed Phi and an interface flows in, it's possible that the meet &
1290 // join report an interface back out. This isn't possible but happens
1291 // because the type system doesn't interact well with interfaces.
1292 const TypePtr *jtp = jt->make_ptr();
1293 const TypeInstPtr *jtip = (jtp != NULL) ? jtp->isa_instptr() : NULL;
1294 const TypeInstKlassPtr *jtkp = (jtp != NULL) ? jtp->isa_instklassptr() : NULL;
1295 if (jtip && ttip) {
1296 if (jtip->is_interface() &&
1297 !ttip->is_interface()) {
1298 assert(ft == ttip->cast_to_ptr_type(jtip->ptr()) ||
1299 ft->isa_narrowoop() && ft->make_ptr() == ttip->cast_to_ptr_type(jtip->ptr()), "");
1300 jt = ft;
1301 }
1302 }
1303 if (jtkp && ttkp) {
1304 if (jtkp->is_interface() &&
1305 !jtkp->klass_is_exact() && // Keep exact interface klass (6894807)
1306 ttkp->is_loaded() && !ttkp->is_interface()) {
1307 assert(ft == ttkp->cast_to_ptr_type(jtkp->ptr()) ||
1308 ft->isa_narrowklass() && ft->make_ptr() == ttkp->cast_to_ptr_type(jtkp->ptr()), "");
1309 jt = ft;
1310 }
1311 }
1312 if (jt != ft && jt->base() == ft->base()) {
1313 if (jt->isa_int() &&
1314 jt->is_int()->_lo == ft->is_int()->_lo &&
1315 jt->is_int()->_hi == ft->is_int()->_hi)
1316 jt = ft;
1317 if (jt->isa_long() &&
1318 jt->is_long()->_lo == ft->is_long()->_lo &&
1319 jt->is_long()->_hi == ft->is_long()->_hi)
1320 jt = ft;
1321 }
1322 if (jt != ft) {
1323 tty->print("merge type: "); t->dump(); tty->cr();
1324 tty->print("kill type: "); _type->dump(); tty->cr();
1325 tty->print("join type: "); jt->dump(); tty->cr();
1326 tty->print("filter type: "); ft->dump(); tty->cr();
1327 }
1328 assert(jt == ft, "");
1329 }
1330 #endif //ASSERT
1331
1332 // Deal with conversion problems found in data loops.
1333 ft = phase->saturate(ft, phase->type_or_null(this), _type);
1334
1335 return ft;
1336 }
1337
1338
1339 //------------------------------is_diamond_phi---------------------------------
1340 // Does this Phi represent a simple well-shaped diamond merge? Return the
1341 // index of the true path or 0 otherwise.
1342 // If check_control_only is true, do not inspect the If node at the
1343 // top, and return -1 (not an edge number) on success.
1344 int PhiNode::is_diamond_phi(bool check_control_only) const {
1345 // Check for a 2-path merge
1346 Node *region = in(0);
1347 if( !region ) return 0;
1348 if( region->req() != 3 ) return 0;
1349 if( req() != 3 ) return 0;
1350 // Check that both paths come from the same If
1351 Node *ifp1 = region->in(1);
1352 Node *ifp2 = region->in(2);
1353 if( !ifp1 || !ifp2 ) return 0;
1354 Node *iff = ifp1->in(0);
1355 if( !iff || !iff->is_If() ) return 0;
1356 if( iff != ifp2->in(0) ) return 0;
1357 if (check_control_only) return -1;
1358 // Check for a proper bool/cmp
1359 const Node *b = iff->in(1);
1360 if( !b->is_Bool() ) return 0;
1361 const Node *cmp = b->in(1);
1362 if( !cmp->is_Cmp() ) return 0;
1363
1364 // Check for branching opposite expected
1365 if( ifp2->Opcode() == Op_IfTrue ) {
1366 assert( ifp1->Opcode() == Op_IfFalse, "" );
1367 return 2;
1368 } else {
1369 assert( ifp1->Opcode() == Op_IfTrue, "" );
1370 return 1;
1371 }
1372 }
1373
1374 //----------------------------check_cmove_id-----------------------------------
1375 // Check for CMove'ing a constant after comparing against the constant.
1376 // Happens all the time now, since if we compare equality vs a constant in
1377 // the parser, we "know" the variable is constant on one path and we force
1378 // it. Thus code like "if( x==0 ) {/*EMPTY*/}" ends up inserting a
1379 // conditional move: "x = (x==0)?0:x;". Yucko. This fix is slightly more
1380 // general in that we don't need constants. Since CMove's are only inserted
1381 // in very special circumstances, we do it here on generic Phi's.
1382 Node* PhiNode::is_cmove_id(PhaseTransform* phase, int true_path) {
1383 assert(true_path !=0, "only diamond shape graph expected");
1384
1385 // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1386 // phi->region->if_proj->ifnode->bool->cmp
1387 Node* region = in(0);
1388 Node* iff = region->in(1)->in(0);
1389 BoolNode* b = iff->in(1)->as_Bool();
1390 Node* cmp = b->in(1);
1391 Node* tval = in(true_path);
1392 Node* fval = in(3-true_path);
1393 Node* id = CMoveNode::is_cmove_id(phase, cmp, tval, fval, b);
1394 if (id == NULL)
1395 return NULL;
1396
1397 // Either value might be a cast that depends on a branch of 'iff'.
1398 // Since the 'id' value will float free of the diamond, either
1399 // decast or return failure.
1400 Node* ctl = id->in(0);
1401 if (ctl != NULL && ctl->in(0) == iff) {
1402 if (id->is_ConstraintCast()) {
1403 return id->in(1);
1404 } else {
1405 // Don't know how to disentangle this value.
1406 return NULL;
1407 }
1408 }
1409
1410 return id;
1411 }
1412
1413 //------------------------------Identity---------------------------------------
1414 // Check for Region being Identity.
1415 Node* PhiNode::Identity(PhaseGVN* phase) {
1416 // Check for no merging going on
1417 // (There used to be special-case code here when this->region->is_Loop.
1418 // It would check for a tributary phi on the backedge that the main phi
1419 // trivially, perhaps with a single cast. The unique_input method
1420 // does all this and more, by reducing such tributaries to 'this'.)
1421 Node* uin = unique_input(phase, false);
1422 if (uin != NULL) {
1423 return uin;
1424 }
1425
1426 int true_path = is_diamond_phi();
1427 // Delay CMove'ing identity if Ideal has not had the chance to handle unsafe cases, yet.
1428 if (true_path != 0 && !(phase->is_IterGVN() && wait_for_region_igvn(phase))) {
1429 Node* id = is_cmove_id(phase, true_path);
1430 if (id != NULL) {
1431 return id;
1432 }
1433 }
1434
1435 if (phase->is_IterGVN()) {
1436 Node* m = try_clean_mem_phi(phase);
1437 if (m != NULL) {
1438 return m;
1439 }
1440 }
1441
1442
1443 // Looking for phis with identical inputs. If we find one that has
1444 // type TypePtr::BOTTOM, replace the current phi with the bottom phi.
1445 if (phase->is_IterGVN() && type() == Type::MEMORY && adr_type() !=
1446 TypePtr::BOTTOM && !adr_type()->is_known_instance()) {
1447 uint phi_len = req();
1448 Node* phi_reg = region();
1449 for (DUIterator_Fast imax, i = phi_reg->fast_outs(imax); i < imax; i++) {
1450 Node* u = phi_reg->fast_out(i);
1451 if (u->is_Phi() && u->as_Phi()->type() == Type::MEMORY &&
1452 u->adr_type() == TypePtr::BOTTOM && u->in(0) == phi_reg &&
1453 u->req() == phi_len) {
1454 for (uint j = 1; j < phi_len; j++) {
1455 if (in(j) != u->in(j)) {
1456 u = NULL;
1457 break;
1458 }
1459 }
1460 if (u != NULL) {
1461 return u;
1462 }
1463 }
1464 }
1465 }
1466
1467 return this; // No identity
1468 }
1469
1470 //-----------------------------unique_input------------------------------------
1471 // Find the unique value, discounting top, self-loops, and casts.
1472 // Return top if there are no inputs, and self if there are multiple.
1473 Node* PhiNode::unique_input(PhaseTransform* phase, bool uncast) {
1474 // 1) One unique direct input,
1475 // or if uncast is true:
1476 // 2) some of the inputs have an intervening ConstraintCast
1477 // 3) an input is a self loop
1478 //
1479 // 1) input or 2) input or 3) input __
1480 // / \ / \ \ / \
1481 // \ / | cast phi cast
1482 // phi \ / / \ /
1483 // phi / --
1484
1485 Node* r = in(0); // RegionNode
1486 Node* input = NULL; // The unique direct input (maybe uncasted = ConstraintCasts removed)
1487
1488 for (uint i = 1, cnt = req(); i < cnt; ++i) {
1489 Node* rc = r->in(i);
1490 if (rc == NULL || phase->type(rc) == Type::TOP)
1491 continue; // ignore unreachable control path
1492 Node* n = in(i);
1493 if (n == NULL)
1494 continue;
1495 Node* un = n;
1496 if (uncast) {
1497 #ifdef ASSERT
1498 Node* m = un->uncast();
1499 #endif
1500 while (un != NULL && un->req() == 2 && un->is_ConstraintCast()) {
1501 Node* next = un->in(1);
1502 if (phase->type(next)->isa_rawptr() && phase->type(un)->isa_oopptr()) {
1503 // risk exposing raw ptr at safepoint
1504 break;
1505 }
1506 un = next;
1507 }
1508 assert(m == un || un->in(1) == m, "Only expected at CheckCastPP from allocation");
1509 }
1510 if (un == NULL || un == this || phase->type(un) == Type::TOP) {
1511 continue; // ignore if top, or in(i) and "this" are in a data cycle
1512 }
1513 // Check for a unique input (maybe uncasted)
1514 if (input == NULL) {
1515 input = un;
1516 } else if (input != un) {
1517 input = NodeSentinel; // no unique input
1518 }
1519 }
1520 if (input == NULL) {
1521 return phase->C->top(); // no inputs
1522 }
1523
1524 if (input != NodeSentinel) {
1525 return input; // one unique direct input
1526 }
1527
1528 // Nothing.
1529 return NULL;
1530 }
1531
1532 //------------------------------is_x2logic-------------------------------------
1533 // Check for simple convert-to-boolean pattern
1534 // If:(C Bool) Region:(IfF IfT) Phi:(Region 0 1)
1535 // Convert Phi to an ConvIB.
1536 static Node *is_x2logic( PhaseGVN *phase, PhiNode *phi, int true_path ) {
1537 assert(true_path !=0, "only diamond shape graph expected");
1538 // Convert the true/false index into an expected 0/1 return.
1539 // Map 2->0 and 1->1.
1540 int flipped = 2-true_path;
1541
1542 // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1543 // phi->region->if_proj->ifnode->bool->cmp
1544 Node *region = phi->in(0);
1545 Node *iff = region->in(1)->in(0);
1546 BoolNode *b = (BoolNode*)iff->in(1);
1547 const CmpNode *cmp = (CmpNode*)b->in(1);
1548
1549 Node *zero = phi->in(1);
1550 Node *one = phi->in(2);
1551 const Type *tzero = phase->type( zero );
1552 const Type *tone = phase->type( one );
1553
1554 // Check for compare vs 0
1555 const Type *tcmp = phase->type(cmp->in(2));
1556 if( tcmp != TypeInt::ZERO && tcmp != TypePtr::NULL_PTR ) {
1557 // Allow cmp-vs-1 if the other input is bounded by 0-1
1558 if( !(tcmp == TypeInt::ONE && phase->type(cmp->in(1)) == TypeInt::BOOL) )
1559 return NULL;
1560 flipped = 1-flipped; // Test is vs 1 instead of 0!
1561 }
1562
1563 // Check for setting zero/one opposite expected
1564 if( tzero == TypeInt::ZERO ) {
1565 if( tone == TypeInt::ONE ) {
1566 } else return NULL;
1567 } else if( tzero == TypeInt::ONE ) {
1568 if( tone == TypeInt::ZERO ) {
1569 flipped = 1-flipped;
1570 } else return NULL;
1571 } else return NULL;
1572
1573 // Check for boolean test backwards
1574 if( b->_test._test == BoolTest::ne ) {
1575 } else if( b->_test._test == BoolTest::eq ) {
1576 flipped = 1-flipped;
1577 } else return NULL;
1578
1579 // Build int->bool conversion
1580 Node *n = new Conv2BNode(cmp->in(1));
1581 if( flipped )
1582 n = new XorINode( phase->transform(n), phase->intcon(1) );
1583
1584 return n;
1585 }
1586
1587 //------------------------------is_cond_add------------------------------------
1588 // Check for simple conditional add pattern: "(P < Q) ? X+Y : X;"
1589 // To be profitable the control flow has to disappear; there can be no other
1590 // values merging here. We replace the test-and-branch with:
1591 // "(sgn(P-Q))&Y) + X". Basically, convert "(P < Q)" into 0 or -1 by
1592 // moving the carry bit from (P-Q) into a register with 'sbb EAX,EAX'.
1593 // Then convert Y to 0-or-Y and finally add.
1594 // This is a key transform for SpecJava _201_compress.
1595 static Node* is_cond_add(PhaseGVN *phase, PhiNode *phi, int true_path) {
1596 assert(true_path !=0, "only diamond shape graph expected");
1597
1598 // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1599 // phi->region->if_proj->ifnode->bool->cmp
1600 RegionNode *region = (RegionNode*)phi->in(0);
1601 Node *iff = region->in(1)->in(0);
1602 BoolNode* b = iff->in(1)->as_Bool();
1603 const CmpNode *cmp = (CmpNode*)b->in(1);
1604
1605 // Make sure only merging this one phi here
1606 if (region->has_unique_phi() != phi) return NULL;
1607
1608 // Make sure each arm of the diamond has exactly one output, which we assume
1609 // is the region. Otherwise, the control flow won't disappear.
1610 if (region->in(1)->outcnt() != 1) return NULL;
1611 if (region->in(2)->outcnt() != 1) return NULL;
1612
1613 // Check for "(P < Q)" of type signed int
1614 if (b->_test._test != BoolTest::lt) return NULL;
1615 if (cmp->Opcode() != Op_CmpI) return NULL;
1616
1617 Node *p = cmp->in(1);
1618 Node *q = cmp->in(2);
1619 Node *n1 = phi->in( true_path);
1620 Node *n2 = phi->in(3-true_path);
1621
1622 int op = n1->Opcode();
1623 if( op != Op_AddI // Need zero as additive identity
1624 /*&&op != Op_SubI &&
1625 op != Op_AddP &&
1626 op != Op_XorI &&
1627 op != Op_OrI*/ )
1628 return NULL;
1629
1630 Node *x = n2;
1631 Node *y = NULL;
1632 if( x == n1->in(1) ) {
1633 y = n1->in(2);
1634 } else if( x == n1->in(2) ) {
1635 y = n1->in(1);
1636 } else return NULL;
1637
1638 // Not so profitable if compare and add are constants
1639 if( q->is_Con() && phase->type(q) != TypeInt::ZERO && y->is_Con() )
1640 return NULL;
1641
1642 Node *cmplt = phase->transform( new CmpLTMaskNode(p,q) );
1643 Node *j_and = phase->transform( new AndINode(cmplt,y) );
1644 return new AddINode(j_and,x);
1645 }
1646
1647 //------------------------------is_absolute------------------------------------
1648 // Check for absolute value.
1649 static Node* is_absolute( PhaseGVN *phase, PhiNode *phi_root, int true_path) {
1650 assert(true_path !=0, "only diamond shape graph expected");
1651
1652 int cmp_zero_idx = 0; // Index of compare input where to look for zero
1653 int phi_x_idx = 0; // Index of phi input where to find naked x
1654
1655 // ABS ends with the merge of 2 control flow paths.
1656 // Find the false path from the true path. With only 2 inputs, 3 - x works nicely.
1657 int false_path = 3 - true_path;
1658
1659 // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1660 // phi->region->if_proj->ifnode->bool->cmp
1661 BoolNode *bol = phi_root->in(0)->in(1)->in(0)->in(1)->as_Bool();
1662 Node *cmp = bol->in(1);
1663
1664 // Check bool sense
1665 if (cmp->Opcode() == Op_CmpF || cmp->Opcode() == Op_CmpD) {
1666 switch (bol->_test._test) {
1667 case BoolTest::lt: cmp_zero_idx = 1; phi_x_idx = true_path; break;
1668 case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break;
1669 case BoolTest::gt: cmp_zero_idx = 2; phi_x_idx = true_path; break;
1670 case BoolTest::ge: cmp_zero_idx = 1; phi_x_idx = false_path; break;
1671 default: return NULL; break;
1672 }
1673 } else if (cmp->Opcode() == Op_CmpI || cmp->Opcode() == Op_CmpL) {
1674 switch (bol->_test._test) {
1675 case BoolTest::lt:
1676 case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break;
1677 case BoolTest::gt:
1678 case BoolTest::ge: cmp_zero_idx = 2; phi_x_idx = true_path; break;
1679 default: return NULL; break;
1680 }
1681 }
1682
1683 // Test is next
1684 const Type *tzero = NULL;
1685 switch (cmp->Opcode()) {
1686 case Op_CmpI: tzero = TypeInt::ZERO; break; // Integer ABS
1687 case Op_CmpL: tzero = TypeLong::ZERO; break; // Long ABS
1688 case Op_CmpF: tzero = TypeF::ZERO; break; // Float ABS
1689 case Op_CmpD: tzero = TypeD::ZERO; break; // Double ABS
1690 default: return NULL;
1691 }
1692
1693 // Find zero input of compare; the other input is being abs'd
1694 Node *x = NULL;
1695 bool flip = false;
1696 if( phase->type(cmp->in(cmp_zero_idx)) == tzero ) {
1697 x = cmp->in(3 - cmp_zero_idx);
1698 } else if( phase->type(cmp->in(3 - cmp_zero_idx)) == tzero ) {
1699 // The test is inverted, we should invert the result...
1700 x = cmp->in(cmp_zero_idx);
1701 flip = true;
1702 } else {
1703 return NULL;
1704 }
1705
1706 // Next get the 2 pieces being selected, one is the original value
1707 // and the other is the negated value.
1708 if( phi_root->in(phi_x_idx) != x ) return NULL;
1709
1710 // Check other phi input for subtract node
1711 Node *sub = phi_root->in(3 - phi_x_idx);
1712
1713 bool is_sub = sub->Opcode() == Op_SubF || sub->Opcode() == Op_SubD ||
1714 sub->Opcode() == Op_SubI || sub->Opcode() == Op_SubL;
1715
1716 // Allow only Sub(0,X) and fail out for all others; Neg is not OK
1717 if (!is_sub || phase->type(sub->in(1)) != tzero || sub->in(2) != x) return NULL;
1718
1719 if (tzero == TypeF::ZERO) {
1720 x = new AbsFNode(x);
1721 if (flip) {
1722 x = new SubFNode(sub->in(1), phase->transform(x));
1723 }
1724 } else if (tzero == TypeD::ZERO) {
1725 x = new AbsDNode(x);
1726 if (flip) {
1727 x = new SubDNode(sub->in(1), phase->transform(x));
1728 }
1729 } else if (tzero == TypeInt::ZERO && Matcher::match_rule_supported(Op_AbsI)) {
1730 x = new AbsINode(x);
1731 if (flip) {
1732 x = new SubINode(sub->in(1), phase->transform(x));
1733 }
1734 } else if (tzero == TypeLong::ZERO && Matcher::match_rule_supported(Op_AbsL)) {
1735 x = new AbsLNode(x);
1736 if (flip) {
1737 x = new SubLNode(sub->in(1), phase->transform(x));
1738 }
1739 } else return NULL;
1740
1741 return x;
1742 }
1743
1744 //------------------------------split_once-------------------------------------
1745 // Helper for split_flow_path
1746 static void split_once(PhaseIterGVN *igvn, Node *phi, Node *val, Node *n, Node *newn) {
1747 igvn->hash_delete(n); // Remove from hash before hacking edges
1748
1749 uint j = 1;
1750 for (uint i = phi->req()-1; i > 0; i--) {
1751 if (phi->in(i) == val) { // Found a path with val?
1752 // Add to NEW Region/Phi, no DU info
1753 newn->set_req( j++, n->in(i) );
1754 // Remove from OLD Region/Phi
1755 n->del_req(i);
1756 }
1757 }
1758
1759 // Register the new node but do not transform it. Cannot transform until the
1760 // entire Region/Phi conglomerate has been hacked as a single huge transform.
1761 igvn->register_new_node_with_optimizer( newn );
1762
1763 // Now I can point to the new node.
1764 n->add_req(newn);
1765 igvn->_worklist.push(n);
1766 }
1767
1768 //------------------------------split_flow_path--------------------------------
1769 // Check for merging identical values and split flow paths
1770 static Node* split_flow_path(PhaseGVN *phase, PhiNode *phi) {
1771 BasicType bt = phi->type()->basic_type();
1772 if( bt == T_ILLEGAL || type2size[bt] <= 0 )
1773 return NULL; // Bail out on funny non-value stuff
1774 if( phi->req() <= 3 ) // Need at least 2 matched inputs and a
1775 return NULL; // third unequal input to be worth doing
1776
1777 // Scan for a constant
1778 uint i;
1779 for( i = 1; i < phi->req()-1; i++ ) {
1780 Node *n = phi->in(i);
1781 if( !n ) return NULL;
1782 if( phase->type(n) == Type::TOP ) return NULL;
1783 if( n->Opcode() == Op_ConP || n->Opcode() == Op_ConN || n->Opcode() == Op_ConNKlass )
1784 break;
1785 }
1786 if( i >= phi->req() ) // Only split for constants
1787 return NULL;
1788
1789 Node *val = phi->in(i); // Constant to split for
1790 uint hit = 0; // Number of times it occurs
1791 Node *r = phi->region();
1792
1793 for( ; i < phi->req(); i++ ){ // Count occurrences of constant
1794 Node *n = phi->in(i);
1795 if( !n ) return NULL;
1796 if( phase->type(n) == Type::TOP ) return NULL;
1797 if( phi->in(i) == val ) {
1798 hit++;
1799 if (PhaseIdealLoop::find_predicate(r->in(i)) != NULL) {
1800 return NULL; // don't split loop entry path
1801 }
1802 }
1803 }
1804
1805 if( hit <= 1 || // Make sure we find 2 or more
1806 hit == phi->req()-1 ) // and not ALL the same value
1807 return NULL;
1808
1809 // Now start splitting out the flow paths that merge the same value.
1810 // Split first the RegionNode.
1811 PhaseIterGVN *igvn = phase->is_IterGVN();
1812 RegionNode *newr = new RegionNode(hit+1);
1813 split_once(igvn, phi, val, r, newr);
1814
1815 // Now split all other Phis than this one
1816 for (DUIterator_Fast kmax, k = r->fast_outs(kmax); k < kmax; k++) {
1817 Node* phi2 = r->fast_out(k);
1818 if( phi2->is_Phi() && phi2->as_Phi() != phi ) {
1819 PhiNode *newphi = PhiNode::make_blank(newr, phi2);
1820 split_once(igvn, phi, val, phi2, newphi);
1821 }
1822 }
1823
1824 // Clean up this guy
1825 igvn->hash_delete(phi);
1826 for( i = phi->req()-1; i > 0; i-- ) {
1827 if( phi->in(i) == val ) {
1828 phi->del_req(i);
1829 }
1830 }
1831 phi->add_req(val);
1832
1833 return phi;
1834 }
1835
1836 //=============================================================================
1837 //------------------------------simple_data_loop_check-------------------------
1838 // Try to determining if the phi node in a simple safe/unsafe data loop.
1839 // Returns:
1840 // enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop };
1841 // Safe - safe case when the phi and it's inputs reference only safe data
1842 // nodes;
1843 // Unsafe - the phi and it's inputs reference unsafe data nodes but there
1844 // is no reference back to the phi - need a graph walk
1845 // to determine if it is in a loop;
1846 // UnsafeLoop - unsafe case when the phi references itself directly or through
1847 // unsafe data node.
1848 // Note: a safe data node is a node which could/never reference itself during
1849 // GVN transformations. For now it is Con, Proj, Phi, CastPP, CheckCastPP.
1850 // I mark Phi nodes as safe node not only because they can reference itself
1851 // but also to prevent mistaking the fallthrough case inside an outer loop
1852 // as dead loop when the phi references itself through an other phi.
1853 PhiNode::LoopSafety PhiNode::simple_data_loop_check(Node *in) const {
1854 // It is unsafe loop if the phi node references itself directly.
1855 if (in == (Node*)this)
1856 return UnsafeLoop; // Unsafe loop
1857 // Unsafe loop if the phi node references itself through an unsafe data node.
1858 // Exclude cases with null inputs or data nodes which could reference
1859 // itself (safe for dead loops).
1860 if (in != NULL && !in->is_dead_loop_safe()) {
1861 // Check inputs of phi's inputs also.
1862 // It is much less expensive then full graph walk.
1863 uint cnt = in->req();
1864 uint i = (in->is_Proj() && !in->is_CFG()) ? 0 : 1;
1865 for (; i < cnt; ++i) {
1866 Node* m = in->in(i);
1867 if (m == (Node*)this)
1868 return UnsafeLoop; // Unsafe loop
1869 if (m != NULL && !m->is_dead_loop_safe()) {
1870 // Check the most common case (about 30% of all cases):
1871 // phi->Load/Store->AddP->(ConP ConP Con)/(Parm Parm Con).
1872 Node *m1 = (m->is_AddP() && m->req() > 3) ? m->in(1) : NULL;
1873 if (m1 == (Node*)this)
1874 return UnsafeLoop; // Unsafe loop
1875 if (m1 != NULL && m1 == m->in(2) &&
1876 m1->is_dead_loop_safe() && m->in(3)->is_Con()) {
1877 continue; // Safe case
1878 }
1879 // The phi references an unsafe node - need full analysis.
1880 return Unsafe;
1881 }
1882 }
1883 }
1884 return Safe; // Safe case - we can optimize the phi node.
1885 }
1886
1887 //------------------------------is_unsafe_data_reference-----------------------
1888 // If phi can be reached through the data input - it is data loop.
1889 bool PhiNode::is_unsafe_data_reference(Node *in) const {
1890 assert(req() > 1, "");
1891 // First, check simple cases when phi references itself directly or
1892 // through an other node.
1893 LoopSafety safety = simple_data_loop_check(in);
1894 if (safety == UnsafeLoop)
1895 return true; // phi references itself - unsafe loop
1896 else if (safety == Safe)
1897 return false; // Safe case - phi could be replaced with the unique input.
1898
1899 // Unsafe case when we should go through data graph to determine
1900 // if the phi references itself.
1901
1902 ResourceMark rm;
1903
1904 Node_List nstack;
1905 VectorSet visited;
1906
1907 nstack.push(in); // Start with unique input.
1908 visited.set(in->_idx);
1909 while (nstack.size() != 0) {
1910 Node* n = nstack.pop();
1911 uint cnt = n->req();
1912 uint i = (n->is_Proj() && !n->is_CFG()) ? 0 : 1;
1913 for (; i < cnt; i++) {
1914 Node* m = n->in(i);
1915 if (m == (Node*)this) {
1916 return true; // Data loop
1917 }
1918 if (m != NULL && !m->is_dead_loop_safe()) { // Only look for unsafe cases.
1919 if (!visited.test_set(m->_idx))
1920 nstack.push(m);
1921 }
1922 }
1923 }
1924 return false; // The phi is not reachable from its inputs
1925 }
1926
1927 // Is this Phi's region or some inputs to the region enqueued for IGVN
1928 // and so could cause the region to be optimized out?
1929 bool PhiNode::wait_for_region_igvn(PhaseGVN* phase) {
1930 PhaseIterGVN* igvn = phase->is_IterGVN();
1931 Unique_Node_List& worklist = igvn->_worklist;
1932 bool delay = false;
1933 Node* r = in(0);
1934 for (uint j = 1; j < req(); j++) {
1935 Node* rc = r->in(j);
1936 Node* n = in(j);
1937 if (rc != NULL &&
1938 rc->is_Proj()) {
1939 if (worklist.member(rc)) {
1940 delay = true;
1941 } else if (rc->in(0) != NULL &&
1942 rc->in(0)->is_If()) {
1943 if (worklist.member(rc->in(0))) {
1944 delay = true;
1945 } else if (rc->in(0)->in(1) != NULL &&
1946 rc->in(0)->in(1)->is_Bool()) {
1947 if (worklist.member(rc->in(0)->in(1))) {
1948 delay = true;
1949 } else if (rc->in(0)->in(1)->in(1) != NULL &&
1950 rc->in(0)->in(1)->in(1)->is_Cmp()) {
1951 if (worklist.member(rc->in(0)->in(1)->in(1))) {
1952 delay = true;
1953 }
1954 }
1955 }
1956 }
1957 }
1958 }
1959 if (delay) {
1960 worklist.push(this);
1961 }
1962 return delay;
1963 }
1964
1965 // Push inline type input nodes (and null) down through the phi recursively (can handle data loops).
1966 InlineTypeNode* PhiNode::push_inline_types_through(PhaseGVN* phase, bool can_reshape, ciInlineKlass* vk, bool is_init) {
1967 InlineTypeNode* vt = InlineTypeNode::make_null(*phase, vk)->clone_with_phis(phase, in(0), is_init);
1968 if (can_reshape) {
1969 // Replace phi right away to be able to use the inline
1970 // type node when reaching the phi again through data loops.
1971 PhaseIterGVN* igvn = phase->is_IterGVN();
1972 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
1973 Node* u = fast_out(i);
1974 igvn->rehash_node_delayed(u);
1975 imax -= u->replace_edge(this, vt);
1976 --i;
1977 }
1978 igvn->rehash_node_delayed(this);
1979 assert(outcnt() == 0, "should be dead now");
1980 }
1981 ResourceMark rm;
1982 Node_List casts;
1983 for (uint i = 1; i < req(); ++i) {
1984 Node* n = in(i);
1985 while (n->is_ConstraintCast()) {
1986 casts.push(n);
1987 n = n->in(1);
1988 }
1989 if (phase->type(n)->is_zero_type()) {
1990 n = InlineTypeNode::make_null(*phase, vk);
1991 } else if (n->is_Phi()) {
1992 assert(can_reshape, "can only handle phis during IGVN");
1993 n = phase->transform(n->as_Phi()->push_inline_types_through(phase, can_reshape, vk, is_init));
1994 }
1995 while (casts.size() != 0) {
1996 // Push the cast(s) through the InlineTypeNode
1997 Node* cast = casts.pop()->clone();
1998 cast->set_req_X(1, n->as_InlineType()->get_oop(), phase);
1999 n = n->clone();
2000 n->as_InlineType()->set_oop(phase->transform(cast));
2001 n = phase->transform(n);
2002 }
2003 bool transform = !can_reshape && (i == (req()-1)); // Transform phis on last merge
2004 vt->merge_with(phase, n->as_InlineType(), i, transform);
2005 }
2006 return vt;
2007 }
2008
2009 //------------------------------Ideal------------------------------------------
2010 // Return a node which is more "ideal" than the current node. Must preserve
2011 // the CFG, but we can still strip out dead paths.
2012 Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) {
2013 Node *r = in(0); // RegionNode
2014 assert(r != NULL && r->is_Region(), "this phi must have a region");
2015 assert(r->in(0) == NULL || !r->in(0)->is_Root(), "not a specially hidden merge");
2016
2017 // Note: During parsing, phis are often transformed before their regions.
2018 // This means we have to use type_or_null to defend against untyped regions.
2019 if( phase->type_or_null(r) == Type::TOP ) // Dead code?
2020 return NULL; // No change
2021
2022 Node *top = phase->C->top();
2023 bool new_phi = (outcnt() == 0); // transforming new Phi
2024 // No change for igvn if new phi is not hooked
2025 if (new_phi && can_reshape)
2026 return NULL;
2027
2028 // The are 2 situations when only one valid phi's input is left
2029 // (in addition to Region input).
2030 // One: region is not loop - replace phi with this input.
2031 // Two: region is loop - replace phi with top since this data path is dead
2032 // and we need to break the dead data loop.
2033 Node* progress = NULL; // Record if any progress made
2034 for( uint j = 1; j < req(); ++j ){ // For all paths in
2035 // Check unreachable control paths
2036 Node* rc = r->in(j);
2037 Node* n = in(j); // Get the input
2038 if (rc == NULL || phase->type(rc) == Type::TOP) {
2039 if (n != top) { // Not already top?
2040 PhaseIterGVN *igvn = phase->is_IterGVN();
2041 if (can_reshape && igvn != NULL) {
2042 igvn->_worklist.push(r);
2043 }
2044 // Nuke it down
2045 set_req_X(j, top, phase);
2046 progress = this; // Record progress
2047 }
2048 }
2049 }
2050
2051 if (can_reshape && outcnt() == 0) {
2052 // set_req() above may kill outputs if Phi is referenced
2053 // only by itself on the dead (top) control path.
2054 return top;
2055 }
2056
2057 bool uncasted = false;
2058 Node* uin = unique_input(phase, false);
2059 if (uin == NULL && can_reshape &&
2060 // If there is a chance that the region can be optimized out do
2061 // not add a cast node that we can't remove yet.
2062 !wait_for_region_igvn(phase)) {
2063 uncasted = true;
2064 uin = unique_input(phase, true);
2065 }
2066 if (uin == top) { // Simplest case: no alive inputs.
2067 if (can_reshape) // IGVN transformation
2068 return top;
2069 else
2070 return NULL; // Identity will return TOP
2071 } else if (uin != NULL) {
2072 // Only one not-NULL unique input path is left.
2073 // Determine if this input is backedge of a loop.
2074 // (Skip new phis which have no uses and dead regions).
2075 if (outcnt() > 0 && r->in(0) != NULL) {
2076 if (is_data_loop(r->as_Region(), uin, phase)) {
2077 // Break this data loop to avoid creation of a dead loop.
2078 if (can_reshape) {
2079 return top;
2080 } else {
2081 // We can't return top if we are in Parse phase - cut inputs only
2082 // let Identity to handle the case.
2083 replace_edge(uin, top, phase);
2084 return NULL;
2085 }
2086 }
2087 }
2088
2089 if (uncasted) {
2090 // Add cast nodes between the phi to be removed and its unique input.
2091 // Wait until after parsing for the type information to propagate from the casts.
2092 assert(can_reshape, "Invalid during parsing");
2093 const Type* phi_type = bottom_type();
2094 // Add casts to carry the control dependency of the Phi that is
2095 // going away
2096 Node* cast = NULL;
2097 if (phi_type->isa_ptr()) {
2098 const Type* uin_type = phase->type(uin);
2099 if (!phi_type->isa_oopptr() && !uin_type->isa_oopptr()) {
2100 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, phi_type, ConstraintCastNode::StrongDependency);
2101 } else {
2102 // Use a CastPP for a cast to not null and a CheckCastPP for
2103 // a cast to a new klass (and both if both null-ness and
2104 // klass change).
2105
2106 // If the type of phi is not null but the type of uin may be
2107 // null, uin's type must be casted to not null
2108 if (phi_type->join(TypePtr::NOTNULL) == phi_type->remove_speculative() &&
2109 uin_type->join(TypePtr::NOTNULL) != uin_type->remove_speculative()) {
2110 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, TypePtr::NOTNULL, ConstraintCastNode::StrongDependency);
2111 }
2112
2113 // If the type of phi and uin, both casted to not null,
2114 // differ the klass of uin must be (check)cast'ed to match
2115 // that of phi
2116 if (phi_type->join_speculative(TypePtr::NOTNULL) != uin_type->join_speculative(TypePtr::NOTNULL)) {
2117 Node* n = uin;
2118 if (cast != NULL) {
2119 cast = phase->transform(cast);
2120 n = cast;
2121 }
2122 cast = ConstraintCastNode::make_cast(Op_CheckCastPP, r, n, phi_type, ConstraintCastNode::StrongDependency);
2123 }
2124 if (cast == NULL) {
2125 cast = ConstraintCastNode::make_cast(Op_CastPP, r, uin, phi_type, ConstraintCastNode::StrongDependency);
2126 }
2127 }
2128 } else {
2129 cast = ConstraintCastNode::make_cast_for_type(r, uin, phi_type, ConstraintCastNode::StrongDependency);
2130 }
2131 assert(cast != NULL, "cast should be set");
2132 cast = phase->transform(cast);
2133 // set all inputs to the new cast(s) so the Phi is removed by Identity
2134 PhaseIterGVN* igvn = phase->is_IterGVN();
2135 for (uint i = 1; i < req(); i++) {
2136 set_req_X(i, cast, igvn);
2137 }
2138 uin = cast;
2139 }
2140
2141 // One unique input.
2142 debug_only(Node* ident = Identity(phase));
2143 // The unique input must eventually be detected by the Identity call.
2144 #ifdef ASSERT
2145 if (ident != uin && !ident->is_top()) {
2146 // print this output before failing assert
2147 r->dump(3);
2148 this->dump(3);
2149 ident->dump();
2150 uin->dump();
2151 }
2152 #endif
2153 assert(ident == uin || ident->is_top(), "Identity must clean this up");
2154 return NULL;
2155 }
2156
2157 Node* opt = NULL;
2158 int true_path = is_diamond_phi();
2159 if (true_path != 0 &&
2160 // If one of the diamond's branch is in the process of dying then, the Phi's input for that branch might transform
2161 // to top. If that happens replacing the Phi with an operation that consumes the Phi's inputs will cause the Phi
2162 // to be replaced by top. To prevent that, delay the transformation until the branch has a chance to be removed.
2163 !(can_reshape && wait_for_region_igvn(phase))) {
2164 // Check for CMove'ing identity. If it would be unsafe,
2165 // handle it here. In the safe case, let Identity handle it.
2166 Node* unsafe_id = is_cmove_id(phase, true_path);
2167 if( unsafe_id != NULL && is_unsafe_data_reference(unsafe_id) )
2168 opt = unsafe_id;
2169
2170 // Check for simple convert-to-boolean pattern
2171 if( opt == NULL )
2172 opt = is_x2logic(phase, this, true_path);
2173
2174 // Check for absolute value
2175 if( opt == NULL )
2176 opt = is_absolute(phase, this, true_path);
2177
2178 // Check for conditional add
2179 if( opt == NULL && can_reshape )
2180 opt = is_cond_add(phase, this, true_path);
2181
2182 // These 4 optimizations could subsume the phi:
2183 // have to check for a dead data loop creation.
2184 if( opt != NULL ) {
2185 if( opt == unsafe_id || is_unsafe_data_reference(opt) ) {
2186 // Found dead loop.
2187 if( can_reshape )
2188 return top;
2189 // We can't return top if we are in Parse phase - cut inputs only
2190 // to stop further optimizations for this phi. Identity will return TOP.
2191 assert(req() == 3, "only diamond merge phi here");
2192 set_req(1, top);
2193 set_req(2, top);
2194 return NULL;
2195 } else {
2196 return opt;
2197 }
2198 }
2199 }
2200
2201 // Check for merging identical values and split flow paths
2202 if (can_reshape) {
2203 opt = split_flow_path(phase, this);
2204 // This optimization only modifies phi - don't need to check for dead loop.
2205 assert(opt == NULL || opt == this, "do not elide phi");
2206 if (opt != NULL) return opt;
2207 }
2208
2209 if (in(1) != NULL && in(1)->Opcode() == Op_AddP && can_reshape) {
2210 // Try to undo Phi of AddP:
2211 // (Phi (AddP base address offset) (AddP base2 address2 offset2))
2212 // becomes:
2213 // newbase := (Phi base base2)
2214 // newaddress := (Phi address address2)
2215 // newoffset := (Phi offset offset2)
2216 // (AddP newbase newaddress newoffset)
2217 //
2218 // This occurs as a result of unsuccessful split_thru_phi and
2219 // interferes with taking advantage of addressing modes. See the
2220 // clone_shift_expressions code in matcher.cpp
2221 Node* addp = in(1);
2222 Node* base = addp->in(AddPNode::Base);
2223 Node* address = addp->in(AddPNode::Address);
2224 Node* offset = addp->in(AddPNode::Offset);
2225 if (base != NULL && address != NULL && offset != NULL &&
2226 !base->is_top() && !address->is_top() && !offset->is_top()) {
2227 const Type* base_type = base->bottom_type();
2228 const Type* address_type = address->bottom_type();
2229 // make sure that all the inputs are similar to the first one,
2230 // i.e. AddP with base == address and same offset as first AddP
2231 bool doit = true;
2232 for (uint i = 2; i < req(); i++) {
2233 if (in(i) == NULL ||
2234 in(i)->Opcode() != Op_AddP ||
2235 in(i)->in(AddPNode::Base) == NULL ||
2236 in(i)->in(AddPNode::Address) == NULL ||
2237 in(i)->in(AddPNode::Offset) == NULL ||
2238 in(i)->in(AddPNode::Base)->is_top() ||
2239 in(i)->in(AddPNode::Address)->is_top() ||
2240 in(i)->in(AddPNode::Offset)->is_top()) {
2241 doit = false;
2242 break;
2243 }
2244 if (in(i)->in(AddPNode::Base) != base) {
2245 base = NULL;
2246 }
2247 if (in(i)->in(AddPNode::Offset) != offset) {
2248 offset = NULL;
2249 }
2250 if (in(i)->in(AddPNode::Address) != address) {
2251 address = NULL;
2252 }
2253 // Accumulate type for resulting Phi
2254 base_type = base_type->meet_speculative(in(i)->in(AddPNode::Base)->bottom_type());
2255 address_type = address_type->meet_speculative(in(i)->in(AddPNode::Address)->bottom_type());
2256 }
2257 if (doit && base == NULL) {
2258 // Check for neighboring AddP nodes in a tree.
2259 // If they have a base, use that it.
2260 for (DUIterator_Fast kmax, k = this->fast_outs(kmax); k < kmax; k++) {
2261 Node* u = this->fast_out(k);
2262 if (u->is_AddP()) {
2263 Node* base2 = u->in(AddPNode::Base);
2264 if (base2 != NULL && !base2->is_top()) {
2265 if (base == NULL)
2266 base = base2;
2267 else if (base != base2)
2268 { doit = false; break; }
2269 }
2270 }
2271 }
2272 }
2273 if (doit) {
2274 if (base == NULL) {
2275 base = new PhiNode(in(0), base_type, NULL);
2276 for (uint i = 1; i < req(); i++) {
2277 base->init_req(i, in(i)->in(AddPNode::Base));
2278 }
2279 phase->is_IterGVN()->register_new_node_with_optimizer(base);
2280 }
2281 if (address == NULL) {
2282 address = new PhiNode(in(0), address_type, NULL);
2283 for (uint i = 1; i < req(); i++) {
2284 address->init_req(i, in(i)->in(AddPNode::Address));
2285 }
2286 phase->is_IterGVN()->register_new_node_with_optimizer(address);
2287 }
2288 if (offset == NULL) {
2289 offset = new PhiNode(in(0), TypeX_X, NULL);
2290 for (uint i = 1; i < req(); i++) {
2291 offset->init_req(i, in(i)->in(AddPNode::Offset));
2292 }
2293 phase->is_IterGVN()->register_new_node_with_optimizer(offset);
2294 }
2295 return new AddPNode(base, address, offset);
2296 }
2297 }
2298 }
2299
2300 // Split phis through memory merges, so that the memory merges will go away.
2301 // Piggy-back this transformation on the search for a unique input....
2302 // It will be as if the merged memory is the unique value of the phi.
2303 // (Do not attempt this optimization unless parsing is complete.
2304 // It would make the parser's memory-merge logic sick.)
2305 // (MergeMemNode is not dead_loop_safe - need to check for dead loop.)
2306 if (progress == NULL && can_reshape && type() == Type::MEMORY) {
2307 // see if this phi should be sliced
2308 uint merge_width = 0;
2309 bool saw_self = false;
2310 // TODO revisit this with JDK-8247216
2311 bool mergemem_only = true;
2312 for( uint i=1; i<req(); ++i ) {// For all paths in
2313 Node *ii = in(i);
2314 // TOP inputs should not be counted as safe inputs because if the
2315 // Phi references itself through all other inputs then splitting the
2316 // Phi through memory merges would create dead loop at later stage.
2317 if (ii == top) {
2318 return NULL; // Delay optimization until graph is cleaned.
2319 }
2320 if (ii->is_MergeMem()) {
2321 MergeMemNode* n = ii->as_MergeMem();
2322 merge_width = MAX2(merge_width, n->req());
2323 saw_self = saw_self || (n->base_memory() == this);
2324 } else {
2325 mergemem_only = false;
2326 }
2327 }
2328
2329 // This restriction is temporarily necessary to ensure termination:
2330 if (!mergemem_only && !saw_self && adr_type() == TypePtr::BOTTOM) merge_width = 0;
2331
2332 if (merge_width > Compile::AliasIdxRaw) {
2333 // found at least one non-empty MergeMem
2334 const TypePtr* at = adr_type();
2335 if (at != TypePtr::BOTTOM) {
2336 // Patch the existing phi to select an input from the merge:
2337 // Phi:AT1(...MergeMem(m0, m1, m2)...) into
2338 // Phi:AT1(...m1...)
2339 int alias_idx = phase->C->get_alias_index(at);
2340 for (uint i=1; i<req(); ++i) {
2341 Node *ii = in(i);
2342 if (ii->is_MergeMem()) {
2343 MergeMemNode* n = ii->as_MergeMem();
2344 // compress paths and change unreachable cycles to TOP
2345 // If not, we can update the input infinitely along a MergeMem cycle
2346 // Equivalent code is in MemNode::Ideal_common
2347 Node *m = phase->transform(n);
2348 if (outcnt() == 0) { // Above transform() may kill us!
2349 return top;
2350 }
2351 // If transformed to a MergeMem, get the desired slice
2352 // Otherwise the returned node represents memory for every slice
2353 Node *new_mem = (m->is_MergeMem()) ?
2354 m->as_MergeMem()->memory_at(alias_idx) : m;
2355 // Update input if it is progress over what we have now
2356 if (new_mem != ii) {
2357 set_req_X(i, new_mem, phase->is_IterGVN());
2358 progress = this;
2359 }
2360 }
2361 }
2362 } else {
2363 // We know that at least one MergeMem->base_memory() == this
2364 // (saw_self == true). If all other inputs also references this phi
2365 // (directly or through data nodes) - it is a dead loop.
2366 bool saw_safe_input = false;
2367 for (uint j = 1; j < req(); ++j) {
2368 Node* n = in(j);
2369 if (n->is_MergeMem()) {
2370 MergeMemNode* mm = n->as_MergeMem();
2371 if (mm->base_memory() == this || mm->base_memory() == mm->empty_memory()) {
2372 // Skip this input if it references back to this phi or if the memory path is dead
2373 continue;
2374 }
2375 }
2376 if (!is_unsafe_data_reference(n)) {
2377 saw_safe_input = true; // found safe input
2378 break;
2379 }
2380 }
2381 if (!saw_safe_input) {
2382 // There is a dead loop: All inputs are either dead or reference back to this phi
2383 return top;
2384 }
2385
2386 // Phi(...MergeMem(m0, m1:AT1, m2:AT2)...) into
2387 // MergeMem(Phi(...m0...), Phi:AT1(...m1...), Phi:AT2(...m2...))
2388 PhaseIterGVN* igvn = phase->is_IterGVN();
2389 assert(igvn != NULL, "sanity check");
2390 Node* hook = new Node(1);
2391 PhiNode* new_base = (PhiNode*) clone();
2392 // Must eagerly register phis, since they participate in loops.
2393 igvn->register_new_node_with_optimizer(new_base);
2394 hook->add_req(new_base);
2395
2396 MergeMemNode* result = MergeMemNode::make(new_base);
2397 for (uint i = 1; i < req(); ++i) {
2398 Node *ii = in(i);
2399 if (ii->is_MergeMem()) {
2400 MergeMemNode* n = ii->as_MergeMem();
2401 if (igvn) {
2402 // TODO revisit this with JDK-8247216
2403 // Put 'n' on the worklist because it might be modified by MergeMemStream::iteration_setup
2404 igvn->_worklist.push(n);
2405 }
2406 for (MergeMemStream mms(result, n); mms.next_non_empty2(); ) {
2407 // If we have not seen this slice yet, make a phi for it.
2408 bool made_new_phi = false;
2409 if (mms.is_empty()) {
2410 Node* new_phi = new_base->slice_memory(mms.adr_type(phase->C));
2411 made_new_phi = true;
2412 igvn->register_new_node_with_optimizer(new_phi);
2413 hook->add_req(new_phi);
2414 mms.set_memory(new_phi);
2415 }
2416 Node* phi = mms.memory();
2417 assert(made_new_phi || phi->in(i) == n, "replace the i-th merge by a slice");
2418 phi->set_req(i, mms.memory2());
2419 }
2420 }
2421 }
2422 // Distribute all self-loops.
2423 { // (Extra braces to hide mms.)
2424 for (MergeMemStream mms(result); mms.next_non_empty(); ) {
2425 Node* phi = mms.memory();
2426 for (uint i = 1; i < req(); ++i) {
2427 if (phi->in(i) == this) phi->set_req(i, phi);
2428 }
2429 }
2430 }
2431 // Already replace this phi node to cut it off from the graph to not interfere in dead loop checks during the
2432 // transformations of the new phi nodes below. Otherwise, we could wrongly conclude that there is no dead loop
2433 // because we are finding this phi node again. Also set the type of the new MergeMem node in case we are also
2434 // visiting it in the transformations below.
2435 igvn->replace_node(this, result);
2436 igvn->set_type(result, result->bottom_type());
2437
2438 // now transform the new nodes, and return the mergemem
2439 for (MergeMemStream mms(result); mms.next_non_empty(); ) {
2440 Node* phi = mms.memory();
2441 mms.set_memory(phase->transform(phi));
2442 }
2443 hook->destruct(igvn);
2444 // Replace self with the result.
2445 return result;
2446 }
2447 }
2448 //
2449 // Other optimizations on the memory chain
2450 //
2451 const TypePtr* at = adr_type();
2452 for( uint i=1; i<req(); ++i ) {// For all paths in
2453 Node *ii = in(i);
2454 Node *new_in = MemNode::optimize_memory_chain(ii, at, NULL, phase);
2455 if (ii != new_in ) {
2456 set_req(i, new_in);
2457 progress = this;
2458 }
2459 }
2460 }
2461
2462 #ifdef _LP64
2463 // Push DecodeN/DecodeNKlass down through phi.
2464 // The rest of phi graph will transform by split EncodeP node though phis up.
2465 if ((UseCompressedOops || UseCompressedClassPointers) && can_reshape && progress == NULL) {
2466 bool may_push = true;
2467 bool has_decodeN = false;
2468 bool is_decodeN = false;
2469 for (uint i=1; i<req(); ++i) {// For all paths in
2470 Node *ii = in(i);
2471 if (ii->is_DecodeNarrowPtr() && ii->bottom_type() == bottom_type()) {
2472 // Do optimization if a non dead path exist.
2473 if (ii->in(1)->bottom_type() != Type::TOP) {
2474 has_decodeN = true;
2475 is_decodeN = ii->is_DecodeN();
2476 }
2477 } else if (!ii->is_Phi()) {
2478 may_push = false;
2479 }
2480 }
2481
2482 if (has_decodeN && may_push) {
2483 PhaseIterGVN *igvn = phase->is_IterGVN();
2484 // Make narrow type for new phi.
2485 const Type* narrow_t;
2486 if (is_decodeN) {
2487 narrow_t = TypeNarrowOop::make(this->bottom_type()->is_ptr());
2488 } else {
2489 narrow_t = TypeNarrowKlass::make(this->bottom_type()->is_ptr());
2490 }
2491 PhiNode* new_phi = new PhiNode(r, narrow_t);
2492 uint orig_cnt = req();
2493 for (uint i=1; i<req(); ++i) {// For all paths in
2494 Node *ii = in(i);
2495 Node* new_ii = NULL;
2496 if (ii->is_DecodeNarrowPtr()) {
2497 assert(ii->bottom_type() == bottom_type(), "sanity");
2498 new_ii = ii->in(1);
2499 } else {
2500 assert(ii->is_Phi(), "sanity");
2501 if (ii->as_Phi() == this) {
2502 new_ii = new_phi;
2503 } else {
2504 if (is_decodeN) {
2505 new_ii = new EncodePNode(ii, narrow_t);
2506 } else {
2507 new_ii = new EncodePKlassNode(ii, narrow_t);
2508 }
2509 igvn->register_new_node_with_optimizer(new_ii);
2510 }
2511 }
2512 new_phi->set_req(i, new_ii);
2513 }
2514 igvn->register_new_node_with_optimizer(new_phi, this);
2515 if (is_decodeN) {
2516 progress = new DecodeNNode(new_phi, bottom_type());
2517 } else {
2518 progress = new DecodeNKlassNode(new_phi, bottom_type());
2519 }
2520 }
2521 }
2522 #endif
2523
2524 // Check recursively if inputs are either an inline type, constant null
2525 // or another Phi (including self references through data loops). If so,
2526 // push the inline types down through the phis to enable folding of loads.
2527 if (EnableValhalla && (_type->isa_ptr() || _type->isa_inlinetype()) && req() > 2) {
2528 ResourceMark rm;
2529 Unique_Node_List worklist;
2530 worklist.push(this);
2531 bool can_optimize = true;
2532 ciInlineKlass* vk = NULL;
2533 // true if all IsInit inputs of all InlineType* nodes are true
2534 bool is_init = true;
2535 Node_List casts;
2536
2537 // TODO 8284443 We need to prevent endless pushing through
2538 // TODO 8284443 We could revisit the same node over and over again, right?
2539 // TestLWorld -XX:+UseZGC -DScenarios=0 -DTest=test69
2540 // TestLWorld -XX:-TieredCompilation -XX:-DoEscapeAnalysis -XX:+AlwaysIncrementalInline
2541 bool only_phi = (outcnt() != 0);
2542 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
2543 Node* n = fast_out(i);
2544 if (n->is_InlineType() && n->in(1) == this) {
2545 can_optimize = false;
2546 break;
2547 }
2548 if (!n->is_Phi()) {
2549 only_phi = false;
2550 }
2551 }
2552 if (only_phi) {
2553 can_optimize = false;
2554 }
2555 for (uint next = 0; next < worklist.size() && can_optimize; next++) {
2556 Node* phi = worklist.at(next);
2557 for (uint i = 1; i < phi->req() && can_optimize; i++) {
2558 Node* n = phi->in(i);
2559 if (n == NULL) {
2560 can_optimize = false;
2561 break;
2562 }
2563 while (n->is_ConstraintCast()) {
2564 if (n->in(0) != NULL && n->in(0)->is_top()) {
2565 // Will die, don't optimize
2566 can_optimize = false;
2567 break;
2568 }
2569 casts.push(n);
2570 n = n->in(1);
2571 }
2572 const Type* t = phase->type(n);
2573 if (n->is_InlineType() && (vk == NULL || vk == t->inline_klass())) {
2574 vk = (vk == NULL) ? t->inline_klass() : vk;
2575 if (phase->find_int_con(n->as_InlineType()->get_is_init(), 0) != 1) {
2576 is_init = false;
2577 }
2578 } else if (n->is_Phi() && can_reshape && (n->bottom_type()->isa_ptr() || n->bottom_type()->isa_inlinetype())) {
2579 worklist.push(n);
2580 } else if (t->is_zero_type()) {
2581 is_init = false;
2582 } else {
2583 can_optimize = false;
2584 }
2585 }
2586 }
2587 // Check if cast nodes can be pushed through
2588 const Type* t = Type::get_const_type(vk);
2589 while (casts.size() != 0 && can_optimize && t != NULL) {
2590 Node* cast = casts.pop();
2591 if (t->filter(cast->bottom_type()) == Type::TOP) {
2592 can_optimize = false;
2593 }
2594 }
2595 if (can_optimize && vk != NULL) {
2596 // TODO 8275400
2597 // assert(!_type->isa_ptr() || _type->maybe_null() || is_init, "Phi not null but a possible null was seen");
2598 return push_inline_types_through(phase, can_reshape, vk, is_init);
2599 }
2600 }
2601
2602 // Phi (VB ... VB) => VB (Phi ...) (Phi ...)
2603 if (EnableVectorReboxing && can_reshape && progress == NULL && type()->isa_oopptr()) {
2604 progress = merge_through_phi(this, phase->is_IterGVN());
2605 }
2606
2607 return progress; // Return any progress
2608 }
2609
2610 Node* PhiNode::clone_through_phi(Node* root_phi, const Type* t, uint c, PhaseIterGVN* igvn) {
2611 Node_Stack stack(1);
2612 VectorSet visited;
2613 Node_List node_map;
2614
2615 stack.push(root_phi, 1); // ignore control
2616 visited.set(root_phi->_idx);
2617
2618 Node* new_phi = new PhiNode(root_phi->in(0), t);
2619 node_map.map(root_phi->_idx, new_phi);
2620
2621 while (stack.is_nonempty()) {
2622 Node* n = stack.node();
2623 uint idx = stack.index();
2624 assert(n->is_Phi(), "not a phi");
2625 if (idx < n->req()) {
2626 stack.set_index(idx + 1);
2627 Node* def = n->in(idx);
2628 if (def == NULL) {
2629 continue; // ignore dead path
2630 } else if (def->is_Phi()) { // inner node
2631 Node* new_phi = node_map[n->_idx];
2632 if (!visited.test_set(def->_idx)) { // not visited yet
2633 node_map.map(def->_idx, new PhiNode(def->in(0), t));
2634 stack.push(def, 1); // ignore control
2635 }
2636 Node* new_in = node_map[def->_idx];
2637 new_phi->set_req(idx, new_in);
2638 } else if (def->Opcode() == Op_VectorBox) { // leaf
2639 assert(n->is_Phi(), "not a phi");
2640 Node* new_phi = node_map[n->_idx];
2641 new_phi->set_req(idx, def->in(c));
2642 } else {
2643 assert(false, "not optimizeable");
2644 return NULL;
2645 }
2646 } else {
2647 Node* new_phi = node_map[n->_idx];
2648 igvn->register_new_node_with_optimizer(new_phi, n);
2649 stack.pop();
2650 }
2651 }
2652 return new_phi;
2653 }
2654
2655 Node* PhiNode::merge_through_phi(Node* root_phi, PhaseIterGVN* igvn) {
2656 Node_Stack stack(1);
2657 VectorSet visited;
2658
2659 stack.push(root_phi, 1); // ignore control
2660 visited.set(root_phi->_idx);
2661
2662 VectorBoxNode* cached_vbox = NULL;
2663 while (stack.is_nonempty()) {
2664 Node* n = stack.node();
2665 uint idx = stack.index();
2666 if (idx < n->req()) {
2667 stack.set_index(idx + 1);
2668 Node* in = n->in(idx);
2669 if (in == NULL) {
2670 continue; // ignore dead path
2671 } else if (in->isa_Phi()) {
2672 if (!visited.test_set(in->_idx)) {
2673 stack.push(in, 1); // ignore control
2674 }
2675 } else if (in->Opcode() == Op_VectorBox) {
2676 VectorBoxNode* vbox = static_cast<VectorBoxNode*>(in);
2677 if (cached_vbox == NULL) {
2678 cached_vbox = vbox;
2679 } else if (vbox->vec_type() != cached_vbox->vec_type()) {
2680 // TODO: vector type mismatch can be handled with additional reinterpret casts
2681 assert(Type::cmp(vbox->vec_type(), cached_vbox->vec_type()) != 0, "inconsistent");
2682 return NULL; // not optimizable: vector type mismatch
2683 } else if (vbox->box_type() != cached_vbox->box_type()) {
2684 assert(Type::cmp(vbox->box_type(), cached_vbox->box_type()) != 0, "inconsistent");
2685 return NULL; // not optimizable: box type mismatch
2686 }
2687 } else {
2688 return NULL; // not optimizable: neither Phi nor VectorBox
2689 }
2690 } else {
2691 stack.pop();
2692 }
2693 }
2694
2695 assert(cached_vbox != NULL, "sanity");
2696 const TypeInstPtr* btype = cached_vbox->box_type();
2697 const TypeVect* vtype = cached_vbox->vec_type();
2698 Node* new_vbox_phi = clone_through_phi(root_phi, btype, VectorBoxNode::Box, igvn);
2699 Node* new_vect_phi = clone_through_phi(root_phi, vtype, VectorBoxNode::Value, igvn);
2700 return new VectorBoxNode(igvn->C, new_vbox_phi, new_vect_phi, btype, vtype);
2701 }
2702
2703 bool PhiNode::is_data_loop(RegionNode* r, Node* uin, const PhaseGVN* phase) {
2704 // First, take the short cut when we know it is a loop and the EntryControl data path is dead.
2705 // The loop node may only have one input because the entry path was removed in PhaseIdealLoop::Dominators().
2706 // Then, check if there is a data loop when the phi references itself directly or through other data nodes.
2707 assert(!r->is_Loop() || r->req() <= 3, "Loop node should have 3 or less inputs");
2708 const bool is_loop = (r->is_Loop() && r->req() == 3);
2709 const Node* top = phase->C->top();
2710 if (is_loop) {
2711 return !uin->eqv_uncast(in(LoopNode::EntryControl));
2712 } else {
2713 // We have a data loop either with an unsafe data reference or if a region is unreachable.
2714 return is_unsafe_data_reference(uin)
2715 || (r->req() == 3 && (r->in(1) != top && r->in(2) == top && r->is_unreachable_region(phase)));
2716 }
2717 }
2718
2719 //------------------------------is_tripcount-----------------------------------
2720 bool PhiNode::is_tripcount(BasicType bt) const {
2721 return (in(0) != NULL && in(0)->is_BaseCountedLoop() &&
2722 in(0)->as_BaseCountedLoop()->bt() == bt &&
2723 in(0)->as_BaseCountedLoop()->phi() == this);
2724 }
2725
2726 //------------------------------out_RegMask------------------------------------
2727 const RegMask &PhiNode::in_RegMask(uint i) const {
2728 return i ? out_RegMask() : RegMask::Empty;
2729 }
2730
2731 const RegMask &PhiNode::out_RegMask() const {
2732 uint ideal_reg = _type->ideal_reg();
2733 assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" );
2734 if( ideal_reg == 0 ) return RegMask::Empty;
2735 assert(ideal_reg != Op_RegFlags, "flags register is not spillable");
2736 return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]);
2737 }
2738
2739 #ifndef PRODUCT
2740 void PhiNode::dump_spec(outputStream *st) const {
2741 TypeNode::dump_spec(st);
2742 if (is_tripcount(T_INT) || is_tripcount(T_LONG)) {
2743 st->print(" #tripcount");
2744 }
2745 }
2746 #endif
2747
2748
2749 //=============================================================================
2750 const Type* GotoNode::Value(PhaseGVN* phase) const {
2751 // If the input is reachable, then we are executed.
2752 // If the input is not reachable, then we are not executed.
2753 return phase->type(in(0));
2754 }
2755
2756 Node* GotoNode::Identity(PhaseGVN* phase) {
2757 return in(0); // Simple copy of incoming control
2758 }
2759
2760 const RegMask &GotoNode::out_RegMask() const {
2761 return RegMask::Empty;
2762 }
2763
2764 //=============================================================================
2765 const RegMask &JumpNode::out_RegMask() const {
2766 return RegMask::Empty;
2767 }
2768
2769 //=============================================================================
2770 const RegMask &JProjNode::out_RegMask() const {
2771 return RegMask::Empty;
2772 }
2773
2774 //=============================================================================
2775 const RegMask &CProjNode::out_RegMask() const {
2776 return RegMask::Empty;
2777 }
2778
2779
2780
2781 //=============================================================================
2782
2783 uint PCTableNode::hash() const { return Node::hash() + _size; }
2784 bool PCTableNode::cmp( const Node &n ) const
2785 { return _size == ((PCTableNode&)n)._size; }
2786
2787 const Type *PCTableNode::bottom_type() const {
2788 const Type** f = TypeTuple::fields(_size);
2789 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL;
2790 return TypeTuple::make(_size, f);
2791 }
2792
2793 //------------------------------Value------------------------------------------
2794 // Compute the type of the PCTableNode. If reachable it is a tuple of
2795 // Control, otherwise the table targets are not reachable
2796 const Type* PCTableNode::Value(PhaseGVN* phase) const {
2797 if( phase->type(in(0)) == Type::CONTROL )
2798 return bottom_type();
2799 return Type::TOP; // All paths dead? Then so are we
2800 }
2801
2802 //------------------------------Ideal------------------------------------------
2803 // Return a node which is more "ideal" than the current node. Strip out
2804 // control copies
2805 Node *PCTableNode::Ideal(PhaseGVN *phase, bool can_reshape) {
2806 return remove_dead_region(phase, can_reshape) ? this : NULL;
2807 }
2808
2809 //=============================================================================
2810 uint JumpProjNode::hash() const {
2811 return Node::hash() + _dest_bci;
2812 }
2813
2814 bool JumpProjNode::cmp( const Node &n ) const {
2815 return ProjNode::cmp(n) &&
2816 _dest_bci == ((JumpProjNode&)n)._dest_bci;
2817 }
2818
2819 #ifndef PRODUCT
2820 void JumpProjNode::dump_spec(outputStream *st) const {
2821 ProjNode::dump_spec(st);
2822 st->print("@bci %d ",_dest_bci);
2823 }
2824
2825 void JumpProjNode::dump_compact_spec(outputStream *st) const {
2826 ProjNode::dump_compact_spec(st);
2827 st->print("(%d)%d@%d", _switch_val, _proj_no, _dest_bci);
2828 }
2829 #endif
2830
2831 //=============================================================================
2832 //------------------------------Value------------------------------------------
2833 // Check for being unreachable, or for coming from a Rethrow. Rethrow's cannot
2834 // have the default "fall_through_index" path.
2835 const Type* CatchNode::Value(PhaseGVN* phase) const {
2836 // Unreachable? Then so are all paths from here.
2837 if( phase->type(in(0)) == Type::TOP ) return Type::TOP;
2838 // First assume all paths are reachable
2839 const Type** f = TypeTuple::fields(_size);
2840 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL;
2841 // Identify cases that will always throw an exception
2842 // () rethrow call
2843 // () virtual or interface call with NULL receiver
2844 // () call is a check cast with incompatible arguments
2845 if( in(1)->is_Proj() ) {
2846 Node *i10 = in(1)->in(0);
2847 if( i10->is_Call() ) {
2848 CallNode *call = i10->as_Call();
2849 // Rethrows always throw exceptions, never return
2850 if (call->entry_point() == OptoRuntime::rethrow_stub()) {
2851 f[CatchProjNode::fall_through_index] = Type::TOP;
2852 } else if (call->is_AllocateArray()) {
2853 Node* klass_node = call->in(AllocateNode::KlassNode);
2854 Node* length = call->in(AllocateNode::ALength);
2855 const Type* length_type = phase->type(length);
2856 const Type* klass_type = phase->type(klass_node);
2857 Node* valid_length_test = call->in(AllocateNode::ValidLengthTest);
2858 const Type* valid_length_test_t = phase->type(valid_length_test);
2859 if (length_type == Type::TOP || klass_type == Type::TOP || valid_length_test_t == Type::TOP ||
2860 valid_length_test_t->is_int()->is_con(0)) {
2861 f[CatchProjNode::fall_through_index] = Type::TOP;
2862 }
2863 } else if( call->req() > TypeFunc::Parms ) {
2864 const Type *arg0 = phase->type( call->in(TypeFunc::Parms) );
2865 // Check for null receiver to virtual or interface calls
2866 if( call->is_CallDynamicJava() &&
2867 arg0->higher_equal(TypePtr::NULL_PTR) ) {
2868 f[CatchProjNode::fall_through_index] = Type::TOP;
2869 }
2870 } // End of if not a runtime stub
2871 } // End of if have call above me
2872 } // End of slot 1 is not a projection
2873 return TypeTuple::make(_size, f);
2874 }
2875
2876 //=============================================================================
2877 uint CatchProjNode::hash() const {
2878 return Node::hash() + _handler_bci;
2879 }
2880
2881
2882 bool CatchProjNode::cmp( const Node &n ) const {
2883 return ProjNode::cmp(n) &&
2884 _handler_bci == ((CatchProjNode&)n)._handler_bci;
2885 }
2886
2887
2888 //------------------------------Identity---------------------------------------
2889 // If only 1 target is possible, choose it if it is the main control
2890 Node* CatchProjNode::Identity(PhaseGVN* phase) {
2891 // If my value is control and no other value is, then treat as ID
2892 const TypeTuple *t = phase->type(in(0))->is_tuple();
2893 if (t->field_at(_con) != Type::CONTROL) return this;
2894 // If we remove the last CatchProj and elide the Catch/CatchProj, then we
2895 // also remove any exception table entry. Thus we must know the call
2896 // feeding the Catch will not really throw an exception. This is ok for
2897 // the main fall-thru control (happens when we know a call can never throw
2898 // an exception) or for "rethrow", because a further optimization will
2899 // yank the rethrow (happens when we inline a function that can throw an
2900 // exception and the caller has no handler). Not legal, e.g., for passing
2901 // a NULL receiver to a v-call, or passing bad types to a slow-check-cast.
2902 // These cases MUST throw an exception via the runtime system, so the VM
2903 // will be looking for a table entry.
2904 Node *proj = in(0)->in(1); // Expect a proj feeding CatchNode
2905 CallNode *call;
2906 if (_con != TypeFunc::Control && // Bail out if not the main control.
2907 !(proj->is_Proj() && // AND NOT a rethrow
2908 proj->in(0)->is_Call() &&
2909 (call = proj->in(0)->as_Call()) &&
2910 call->entry_point() == OptoRuntime::rethrow_stub()))
2911 return this;
2912
2913 // Search for any other path being control
2914 for (uint i = 0; i < t->cnt(); i++) {
2915 if (i != _con && t->field_at(i) == Type::CONTROL)
2916 return this;
2917 }
2918 // Only my path is possible; I am identity on control to the jump
2919 return in(0)->in(0);
2920 }
2921
2922
2923 #ifndef PRODUCT
2924 void CatchProjNode::dump_spec(outputStream *st) const {
2925 ProjNode::dump_spec(st);
2926 st->print("@bci %d ",_handler_bci);
2927 }
2928 #endif
2929
2930 //=============================================================================
2931 //------------------------------Identity---------------------------------------
2932 // Check for CreateEx being Identity.
2933 Node* CreateExNode::Identity(PhaseGVN* phase) {
2934 if( phase->type(in(1)) == Type::TOP ) return in(1);
2935 if( phase->type(in(0)) == Type::TOP ) return in(0);
2936 // We only come from CatchProj, unless the CatchProj goes away.
2937 // If the CatchProj is optimized away, then we just carry the
2938 // exception oop through.
2939
2940 // CheckCastPPNode::Ideal() for inline types reuses the exception
2941 // paths of a call to perform an allocation: we can see a Phi here.
2942 if (in(1)->is_Phi()) {
2943 return this;
2944 }
2945 CallNode *call = in(1)->in(0)->as_Call();
2946
2947 return ( in(0)->is_CatchProj() && in(0)->in(0)->in(1) == in(1) )
2948 ? this
2949 : call->in(TypeFunc::Parms);
2950 }
2951
2952 //=============================================================================
2953 //------------------------------Value------------------------------------------
2954 // Check for being unreachable.
2955 const Type* NeverBranchNode::Value(PhaseGVN* phase) const {
2956 if (!in(0) || in(0)->is_top()) return Type::TOP;
2957 return bottom_type();
2958 }
2959
2960 //------------------------------Ideal------------------------------------------
2961 // Check for no longer being part of a loop
2962 Node *NeverBranchNode::Ideal(PhaseGVN *phase, bool can_reshape) {
2963 if (can_reshape && !in(0)->is_Region()) {
2964 // Dead code elimination can sometimes delete this projection so
2965 // if it's not there, there's nothing to do.
2966 Node* fallthru = proj_out_or_null(0);
2967 if (fallthru != NULL) {
2968 phase->is_IterGVN()->replace_node(fallthru, in(0));
2969 }
2970 return phase->C->top();
2971 }
2972 return NULL;
2973 }
2974
2975 #ifndef PRODUCT
2976 void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const {
2977 st->print("%s", Name());
2978 }
2979 #endif