Mercurial > hg > truffle
comparison src/share/vm/opto/cfgnode.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | 2a9af0b9cb1c |
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1 /* | |
2 * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved. | |
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 // Portions of code courtesy of Clifford Click | |
26 | |
27 // Optimization - Graph Style | |
28 | |
29 #include "incls/_precompiled.incl" | |
30 #include "incls/_cfgnode.cpp.incl" | |
31 | |
32 //============================================================================= | |
33 //------------------------------Value------------------------------------------ | |
34 // Compute the type of the RegionNode. | |
35 const Type *RegionNode::Value( PhaseTransform *phase ) const { | |
36 for( uint i=1; i<req(); ++i ) { // For all paths in | |
37 Node *n = in(i); // Get Control source | |
38 if( !n ) continue; // Missing inputs are TOP | |
39 if( phase->type(n) == Type::CONTROL ) | |
40 return Type::CONTROL; | |
41 } | |
42 return Type::TOP; // All paths dead? Then so are we | |
43 } | |
44 | |
45 //------------------------------Identity--------------------------------------- | |
46 // Check for Region being Identity. | |
47 Node *RegionNode::Identity( PhaseTransform *phase ) { | |
48 // Cannot have Region be an identity, even if it has only 1 input. | |
49 // Phi users cannot have their Region input folded away for them, | |
50 // since they need to select the proper data input | |
51 return this; | |
52 } | |
53 | |
54 //------------------------------merge_region----------------------------------- | |
55 // If a Region flows into a Region, merge into one big happy merge. This is | |
56 // hard to do if there is stuff that has to happen | |
57 static Node *merge_region(RegionNode *region, PhaseGVN *phase) { | |
58 if( region->Opcode() != Op_Region ) // Do not do to LoopNodes | |
59 return NULL; | |
60 Node *progress = NULL; // Progress flag | |
61 PhaseIterGVN *igvn = phase->is_IterGVN(); | |
62 | |
63 uint rreq = region->req(); | |
64 for( uint i = 1; i < rreq; i++ ) { | |
65 Node *r = region->in(i); | |
66 if( r && r->Opcode() == Op_Region && // Found a region? | |
67 r->in(0) == r && // Not already collapsed? | |
68 r != region && // Avoid stupid situations | |
69 r->outcnt() == 2 ) { // Self user and 'region' user only? | |
70 assert(!r->as_Region()->has_phi(), "no phi users"); | |
71 if( !progress ) { // No progress | |
72 if (region->has_phi()) { | |
73 return NULL; // Only flatten if no Phi users | |
74 // igvn->hash_delete( phi ); | |
75 } | |
76 igvn->hash_delete( region ); | |
77 progress = region; // Making progress | |
78 } | |
79 igvn->hash_delete( r ); | |
80 | |
81 // Append inputs to 'r' onto 'region' | |
82 for( uint j = 1; j < r->req(); j++ ) { | |
83 // Move an input from 'r' to 'region' | |
84 region->add_req(r->in(j)); | |
85 r->set_req(j, phase->C->top()); | |
86 // Update phis of 'region' | |
87 //for( uint k = 0; k < max; k++ ) { | |
88 // Node *phi = region->out(k); | |
89 // if( phi->is_Phi() ) { | |
90 // phi->add_req(phi->in(i)); | |
91 // } | |
92 //} | |
93 | |
94 rreq++; // One more input to Region | |
95 } // Found a region to merge into Region | |
96 // Clobber pointer to the now dead 'r' | |
97 region->set_req(i, phase->C->top()); | |
98 } | |
99 } | |
100 | |
101 return progress; | |
102 } | |
103 | |
104 | |
105 | |
106 //--------------------------------has_phi-------------------------------------- | |
107 // Helper function: Return any PhiNode that uses this region or NULL | |
108 PhiNode* RegionNode::has_phi() const { | |
109 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { | |
110 Node* phi = fast_out(i); | |
111 if (phi->is_Phi()) { // Check for Phi users | |
112 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); | |
113 return phi->as_Phi(); // this one is good enough | |
114 } | |
115 } | |
116 | |
117 return NULL; | |
118 } | |
119 | |
120 | |
121 //-----------------------------has_unique_phi---------------------------------- | |
122 // Helper function: Return the only PhiNode that uses this region or NULL | |
123 PhiNode* RegionNode::has_unique_phi() const { | |
124 // Check that only one use is a Phi | |
125 PhiNode* only_phi = NULL; | |
126 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { | |
127 Node* phi = fast_out(i); | |
128 if (phi->is_Phi()) { // Check for Phi users | |
129 assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); | |
130 if (only_phi == NULL) { | |
131 only_phi = phi->as_Phi(); | |
132 } else { | |
133 return NULL; // multiple phis | |
134 } | |
135 } | |
136 } | |
137 | |
138 return only_phi; | |
139 } | |
140 | |
141 | |
142 //------------------------------check_phi_clipping----------------------------- | |
143 // Helper function for RegionNode's identification of FP clipping | |
144 // Check inputs to the Phi | |
145 static bool check_phi_clipping( PhiNode *phi, ConNode * &min, uint &min_idx, ConNode * &max, uint &max_idx, Node * &val, uint &val_idx ) { | |
146 min = NULL; | |
147 max = NULL; | |
148 val = NULL; | |
149 min_idx = 0; | |
150 max_idx = 0; | |
151 val_idx = 0; | |
152 uint phi_max = phi->req(); | |
153 if( phi_max == 4 ) { | |
154 for( uint j = 1; j < phi_max; ++j ) { | |
155 Node *n = phi->in(j); | |
156 int opcode = n->Opcode(); | |
157 switch( opcode ) { | |
158 case Op_ConI: | |
159 { | |
160 if( min == NULL ) { | |
161 min = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; | |
162 min_idx = j; | |
163 } else { | |
164 max = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; | |
165 max_idx = j; | |
166 if( min->get_int() > max->get_int() ) { | |
167 // Swap min and max | |
168 ConNode *temp; | |
169 uint temp_idx; | |
170 temp = min; min = max; max = temp; | |
171 temp_idx = min_idx; min_idx = max_idx; max_idx = temp_idx; | |
172 } | |
173 } | |
174 } | |
175 break; | |
176 default: | |
177 { | |
178 val = n; | |
179 val_idx = j; | |
180 } | |
181 break; | |
182 } | |
183 } | |
184 } | |
185 return ( min && max && val && (min->get_int() <= 0) && (max->get_int() >=0) ); | |
186 } | |
187 | |
188 | |
189 //------------------------------check_if_clipping------------------------------ | |
190 // Helper function for RegionNode's identification of FP clipping | |
191 // Check that inputs to Region come from two IfNodes, | |
192 // | |
193 // If | |
194 // False True | |
195 // If | | |
196 // False True | | |
197 // | | | | |
198 // RegionNode_inputs | |
199 // | |
200 static bool check_if_clipping( const RegionNode *region, IfNode * &bot_if, IfNode * &top_if ) { | |
201 top_if = NULL; | |
202 bot_if = NULL; | |
203 | |
204 // Check control structure above RegionNode for (if ( if ) ) | |
205 Node *in1 = region->in(1); | |
206 Node *in2 = region->in(2); | |
207 Node *in3 = region->in(3); | |
208 // Check that all inputs are projections | |
209 if( in1->is_Proj() && in2->is_Proj() && in3->is_Proj() ) { | |
210 Node *in10 = in1->in(0); | |
211 Node *in20 = in2->in(0); | |
212 Node *in30 = in3->in(0); | |
213 // Check that #1 and #2 are ifTrue and ifFalse from same If | |
214 if( in10 != NULL && in10->is_If() && | |
215 in20 != NULL && in20->is_If() && | |
216 in30 != NULL && in30->is_If() && in10 == in20 && | |
217 (in1->Opcode() != in2->Opcode()) ) { | |
218 Node *in100 = in10->in(0); | |
219 Node *in1000 = (in100 != NULL && in100->is_Proj()) ? in100->in(0) : NULL; | |
220 // Check that control for in10 comes from other branch of IF from in3 | |
221 if( in1000 != NULL && in1000->is_If() && | |
222 in30 == in1000 && (in3->Opcode() != in100->Opcode()) ) { | |
223 // Control pattern checks | |
224 top_if = (IfNode*)in1000; | |
225 bot_if = (IfNode*)in10; | |
226 } | |
227 } | |
228 } | |
229 | |
230 return (top_if != NULL); | |
231 } | |
232 | |
233 | |
234 //------------------------------check_convf2i_clipping------------------------- | |
235 // Helper function for RegionNode's identification of FP clipping | |
236 // Verify that the value input to the phi comes from "ConvF2I; LShift; RShift" | |
237 static bool check_convf2i_clipping( PhiNode *phi, uint idx, ConvF2INode * &convf2i, Node *min, Node *max) { | |
238 convf2i = NULL; | |
239 | |
240 // Check for the RShiftNode | |
241 Node *rshift = phi->in(idx); | |
242 assert( rshift, "Previous checks ensure phi input is present"); | |
243 if( rshift->Opcode() != Op_RShiftI ) { return false; } | |
244 | |
245 // Check for the LShiftNode | |
246 Node *lshift = rshift->in(1); | |
247 assert( lshift, "Previous checks ensure phi input is present"); | |
248 if( lshift->Opcode() != Op_LShiftI ) { return false; } | |
249 | |
250 // Check for the ConvF2INode | |
251 Node *conv = lshift->in(1); | |
252 if( conv->Opcode() != Op_ConvF2I ) { return false; } | |
253 | |
254 // Check that shift amounts are only to get sign bits set after F2I | |
255 jint max_cutoff = max->get_int(); | |
256 jint min_cutoff = min->get_int(); | |
257 jint left_shift = lshift->in(2)->get_int(); | |
258 jint right_shift = rshift->in(2)->get_int(); | |
259 jint max_post_shift = nth_bit(BitsPerJavaInteger - left_shift - 1); | |
260 if( left_shift != right_shift || | |
261 0 > left_shift || left_shift >= BitsPerJavaInteger || | |
262 max_post_shift < max_cutoff || | |
263 max_post_shift < -min_cutoff ) { | |
264 // Shifts are necessary but current transformation eliminates them | |
265 return false; | |
266 } | |
267 | |
268 // OK to return the result of ConvF2I without shifting | |
269 convf2i = (ConvF2INode*)conv; | |
270 return true; | |
271 } | |
272 | |
273 | |
274 //------------------------------check_compare_clipping------------------------- | |
275 // Helper function for RegionNode's identification of FP clipping | |
276 static bool check_compare_clipping( bool less_than, IfNode *iff, ConNode *limit, Node * & input ) { | |
277 Node *i1 = iff->in(1); | |
278 if ( !i1->is_Bool() ) { return false; } | |
279 BoolNode *bool1 = i1->as_Bool(); | |
280 if( less_than && bool1->_test._test != BoolTest::le ) { return false; } | |
281 else if( !less_than && bool1->_test._test != BoolTest::lt ) { return false; } | |
282 const Node *cmpF = bool1->in(1); | |
283 if( cmpF->Opcode() != Op_CmpF ) { return false; } | |
284 // Test that the float value being compared against | |
285 // is equivalent to the int value used as a limit | |
286 Node *nodef = cmpF->in(2); | |
287 if( nodef->Opcode() != Op_ConF ) { return false; } | |
288 jfloat conf = nodef->getf(); | |
289 jint coni = limit->get_int(); | |
290 if( ((int)conf) != coni ) { return false; } | |
291 input = cmpF->in(1); | |
292 return true; | |
293 } | |
294 | |
295 //------------------------------is_unreachable_region-------------------------- | |
296 // Find if the Region node is reachable from the root. | |
297 bool RegionNode::is_unreachable_region(PhaseGVN *phase) const { | |
298 assert(req() == 2, ""); | |
299 | |
300 // First, cut the simple case of fallthrough region when NONE of | |
301 // region's phis references itself directly or through a data node. | |
302 uint max = outcnt(); | |
303 uint i; | |
304 for (i = 0; i < max; i++) { | |
305 Node* phi = raw_out(i); | |
306 if (phi != NULL && phi->is_Phi()) { | |
307 assert(phase->eqv(phi->in(0), this) && phi->req() == 2, ""); | |
308 if (phi->outcnt() == 0) | |
309 continue; // Safe case - no loops | |
310 if (phi->outcnt() == 1) { | |
311 Node* u = phi->raw_out(0); | |
312 // Skip if only one use is an other Phi or Call or Uncommon trap. | |
313 // It is safe to consider this case as fallthrough. | |
314 if (u != NULL && (u->is_Phi() || u->is_CFG())) | |
315 continue; | |
316 } | |
317 // Check when phi references itself directly or through an other node. | |
318 if (phi->as_Phi()->simple_data_loop_check(phi->in(1)) >= PhiNode::Unsafe) | |
319 break; // Found possible unsafe data loop. | |
320 } | |
321 } | |
322 if (i >= max) | |
323 return false; // An unsafe case was NOT found - don't need graph walk. | |
324 | |
325 // Unsafe case - check if the Region node is reachable from root. | |
326 ResourceMark rm; | |
327 | |
328 Arena *a = Thread::current()->resource_area(); | |
329 Node_List nstack(a); | |
330 VectorSet visited(a); | |
331 | |
332 // Mark all control nodes reachable from root outputs | |
333 Node *n = (Node*)phase->C->root(); | |
334 nstack.push(n); | |
335 visited.set(n->_idx); | |
336 while (nstack.size() != 0) { | |
337 n = nstack.pop(); | |
338 uint max = n->outcnt(); | |
339 for (uint i = 0; i < max; i++) { | |
340 Node* m = n->raw_out(i); | |
341 if (m != NULL && m->is_CFG()) { | |
342 if (phase->eqv(m, this)) { | |
343 return false; // We reached the Region node - it is not dead. | |
344 } | |
345 if (!visited.test_set(m->_idx)) | |
346 nstack.push(m); | |
347 } | |
348 } | |
349 } | |
350 | |
351 return true; // The Region node is unreachable - it is dead. | |
352 } | |
353 | |
354 //------------------------------Ideal------------------------------------------ | |
355 // Return a node which is more "ideal" than the current node. Must preserve | |
356 // the CFG, but we can still strip out dead paths. | |
357 Node *RegionNode::Ideal(PhaseGVN *phase, bool can_reshape) { | |
358 if( !can_reshape && !in(0) ) return NULL; // Already degraded to a Copy | |
359 assert(!in(0) || !in(0)->is_Root(), "not a specially hidden merge"); | |
360 | |
361 // Check for RegionNode with no Phi users and both inputs come from either | |
362 // arm of the same IF. If found, then the control-flow split is useless. | |
363 bool has_phis = false; | |
364 if (can_reshape) { // Need DU info to check for Phi users | |
365 has_phis = (has_phi() != NULL); // Cache result | |
366 if (!has_phis) { // No Phi users? Nothing merging? | |
367 for (uint i = 1; i < req()-1; i++) { | |
368 Node *if1 = in(i); | |
369 if( !if1 ) continue; | |
370 Node *iff = if1->in(0); | |
371 if( !iff || !iff->is_If() ) continue; | |
372 for( uint j=i+1; j<req(); j++ ) { | |
373 if( in(j) && in(j)->in(0) == iff && | |
374 if1->Opcode() != in(j)->Opcode() ) { | |
375 // Add the IF Projections to the worklist. They (and the IF itself) | |
376 // will be eliminated if dead. | |
377 phase->is_IterGVN()->add_users_to_worklist(iff); | |
378 set_req(i, iff->in(0));// Skip around the useless IF diamond | |
379 set_req(j, NULL); | |
380 return this; // Record progress | |
381 } | |
382 } | |
383 } | |
384 } | |
385 } | |
386 | |
387 // Remove TOP or NULL input paths. If only 1 input path remains, this Region | |
388 // degrades to a copy. | |
389 bool add_to_worklist = false; | |
390 int cnt = 0; // Count of values merging | |
391 DEBUG_ONLY( int cnt_orig = req(); ) // Save original inputs count | |
392 int del_it = 0; // The last input path we delete | |
393 // For all inputs... | |
394 for( uint i=1; i<req(); ++i ){// For all paths in | |
395 Node *n = in(i); // Get the input | |
396 if( n != NULL ) { | |
397 // Remove useless control copy inputs | |
398 if( n->is_Region() && n->as_Region()->is_copy() ) { | |
399 set_req(i, n->nonnull_req()); | |
400 i--; | |
401 continue; | |
402 } | |
403 if( n->is_Proj() ) { // Remove useless rethrows | |
404 Node *call = n->in(0); | |
405 if (call->is_Call() && call->as_Call()->entry_point() == OptoRuntime::rethrow_stub()) { | |
406 set_req(i, call->in(0)); | |
407 i--; | |
408 continue; | |
409 } | |
410 } | |
411 if( phase->type(n) == Type::TOP ) { | |
412 set_req(i, NULL); // Ignore TOP inputs | |
413 i--; | |
414 continue; | |
415 } | |
416 cnt++; // One more value merging | |
417 | |
418 } else if (can_reshape) { // Else found dead path with DU info | |
419 PhaseIterGVN *igvn = phase->is_IterGVN(); | |
420 del_req(i); // Yank path from self | |
421 del_it = i; | |
422 uint max = outcnt(); | |
423 DUIterator j; | |
424 bool progress = true; | |
425 while(progress) { // Need to establish property over all users | |
426 progress = false; | |
427 for (j = outs(); has_out(j); j++) { | |
428 Node *n = out(j); | |
429 if( n->req() != req() && n->is_Phi() ) { | |
430 assert( n->in(0) == this, "" ); | |
431 igvn->hash_delete(n); // Yank from hash before hacking edges | |
432 n->set_req_X(i,NULL,igvn);// Correct DU info | |
433 n->del_req(i); // Yank path from Phis | |
434 if( max != outcnt() ) { | |
435 progress = true; | |
436 j = refresh_out_pos(j); | |
437 max = outcnt(); | |
438 } | |
439 } | |
440 } | |
441 } | |
442 add_to_worklist = true; | |
443 i--; | |
444 } | |
445 } | |
446 | |
447 if (can_reshape && cnt == 1) { | |
448 // Is it dead loop? | |
449 // If it is LoopNopde it had 2 (+1 itself) inputs and | |
450 // one of them was cut. The loop is dead if it was EntryContol. | |
451 assert(!this->is_Loop() || cnt_orig == 3, "Loop node should have 3 inputs"); | |
452 if (this->is_Loop() && del_it == LoopNode::EntryControl || | |
453 !this->is_Loop() && has_phis && is_unreachable_region(phase)) { | |
454 // Yes, the region will be removed during the next step below. | |
455 // Cut the backedge input and remove phis since no data paths left. | |
456 // We don't cut outputs to other nodes here since we need to put them | |
457 // on the worklist. | |
458 del_req(1); | |
459 cnt = 0; | |
460 assert( req() == 1, "no more inputs expected" ); | |
461 uint max = outcnt(); | |
462 bool progress = true; | |
463 Node *top = phase->C->top(); | |
464 PhaseIterGVN *igvn = phase->is_IterGVN(); | |
465 DUIterator j; | |
466 while(progress) { | |
467 progress = false; | |
468 for (j = outs(); has_out(j); j++) { | |
469 Node *n = out(j); | |
470 if( n->is_Phi() ) { | |
471 assert( igvn->eqv(n->in(0), this), "" ); | |
472 assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" ); | |
473 // Break dead loop data path. | |
474 // Eagerly replace phis with top to avoid phis copies generation. | |
475 igvn->add_users_to_worklist(n); | |
476 igvn->hash_delete(n); // Yank from hash before hacking edges | |
477 igvn->subsume_node(n, top); | |
478 if( max != outcnt() ) { | |
479 progress = true; | |
480 j = refresh_out_pos(j); | |
481 max = outcnt(); | |
482 } | |
483 } | |
484 } | |
485 } | |
486 add_to_worklist = true; | |
487 } | |
488 } | |
489 if (add_to_worklist) { | |
490 phase->is_IterGVN()->add_users_to_worklist(this); // Revisit collapsed Phis | |
491 } | |
492 | |
493 if( cnt <= 1 ) { // Only 1 path in? | |
494 set_req(0, NULL); // Null control input for region copy | |
495 if( cnt == 0 && !can_reshape) { // Parse phase - leave the node as it is. | |
496 // No inputs or all inputs are NULL. | |
497 return NULL; | |
498 } else if (can_reshape) { // Optimization phase - remove the node | |
499 PhaseIterGVN *igvn = phase->is_IterGVN(); | |
500 Node *parent_ctrl; | |
501 if( cnt == 0 ) { | |
502 assert( req() == 1, "no inputs expected" ); | |
503 // During IGVN phase such region will be subsumed by TOP node | |
504 // so region's phis will have TOP as control node. | |
505 // Kill phis here to avoid it. PhiNode::is_copy() will be always false. | |
506 // Also set other user's input to top. | |
507 parent_ctrl = phase->C->top(); | |
508 } else { | |
509 // The fallthrough case since we already checked dead loops above. | |
510 parent_ctrl = in(1); | |
511 assert(parent_ctrl != NULL, "Region is a copy of some non-null control"); | |
512 assert(!igvn->eqv(parent_ctrl, this), "Close dead loop"); | |
513 } | |
514 if (!add_to_worklist) | |
515 igvn->add_users_to_worklist(this); // Check for further allowed opts | |
516 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) { | |
517 Node* n = last_out(i); | |
518 igvn->hash_delete(n); // Remove from worklist before modifying edges | |
519 if( n->is_Phi() ) { // Collapse all Phis | |
520 // Eagerly replace phis to avoid copies generation. | |
521 igvn->add_users_to_worklist(n); | |
522 igvn->hash_delete(n); // Yank from hash before hacking edges | |
523 if( cnt == 0 ) { | |
524 assert( n->req() == 1, "No data inputs expected" ); | |
525 igvn->subsume_node(n, parent_ctrl); // replaced by top | |
526 } else { | |
527 assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" ); | |
528 Node* in1 = n->in(1); // replaced by unique input | |
529 if( n->as_Phi()->is_unsafe_data_reference(in1) ) | |
530 in1 = phase->C->top(); // replaced by top | |
531 igvn->subsume_node(n, in1); | |
532 } | |
533 } | |
534 else if( n->is_Region() ) { // Update all incoming edges | |
535 assert( !igvn->eqv(n, this), "Must be removed from DefUse edges"); | |
536 uint uses_found = 0; | |
537 for( uint k=1; k < n->req(); k++ ) { | |
538 if( n->in(k) == this ) { | |
539 n->set_req(k, parent_ctrl); | |
540 uses_found++; | |
541 } | |
542 } | |
543 if( uses_found > 1 ) { // (--i) done at the end of the loop. | |
544 i -= (uses_found - 1); | |
545 } | |
546 } | |
547 else { | |
548 assert( igvn->eqv(n->in(0), this), "Expect RegionNode to be control parent"); | |
549 n->set_req(0, parent_ctrl); | |
550 } | |
551 #ifdef ASSERT | |
552 for( uint k=0; k < n->req(); k++ ) { | |
553 assert( !igvn->eqv(n->in(k), this), "All uses of RegionNode should be gone"); | |
554 } | |
555 #endif | |
556 } | |
557 // Remove the RegionNode itself from DefUse info | |
558 igvn->remove_dead_node(this); | |
559 return NULL; | |
560 } | |
561 return this; // Record progress | |
562 } | |
563 | |
564 | |
565 // If a Region flows into a Region, merge into one big happy merge. | |
566 if (can_reshape) { | |
567 Node *m = merge_region(this, phase); | |
568 if (m != NULL) return m; | |
569 } | |
570 | |
571 // Check if this region is the root of a clipping idiom on floats | |
572 if( ConvertFloat2IntClipping && can_reshape && req() == 4 ) { | |
573 // Check that only one use is a Phi and that it simplifies to two constants + | |
574 PhiNode* phi = has_unique_phi(); | |
575 if (phi != NULL) { // One Phi user | |
576 // Check inputs to the Phi | |
577 ConNode *min; | |
578 ConNode *max; | |
579 Node *val; | |
580 uint min_idx; | |
581 uint max_idx; | |
582 uint val_idx; | |
583 if( check_phi_clipping( phi, min, min_idx, max, max_idx, val, val_idx ) ) { | |
584 IfNode *top_if; | |
585 IfNode *bot_if; | |
586 if( check_if_clipping( this, bot_if, top_if ) ) { | |
587 // Control pattern checks, now verify compares | |
588 Node *top_in = NULL; // value being compared against | |
589 Node *bot_in = NULL; | |
590 if( check_compare_clipping( true, bot_if, min, bot_in ) && | |
591 check_compare_clipping( false, top_if, max, top_in ) ) { | |
592 if( bot_in == top_in ) { | |
593 PhaseIterGVN *gvn = phase->is_IterGVN(); | |
594 assert( gvn != NULL, "Only had DefUse info in IterGVN"); | |
595 // Only remaining check is that bot_in == top_in == (Phi's val + mods) | |
596 | |
597 // Check for the ConvF2INode | |
598 ConvF2INode *convf2i; | |
599 if( check_convf2i_clipping( phi, val_idx, convf2i, min, max ) && | |
600 convf2i->in(1) == bot_in ) { | |
601 // Matched pattern, including LShiftI; RShiftI, replace with integer compares | |
602 // max test | |
603 Node *cmp = gvn->register_new_node_with_optimizer(new (phase->C, 3) CmpINode( convf2i, min )); | |
604 Node *boo = gvn->register_new_node_with_optimizer(new (phase->C, 2) BoolNode( cmp, BoolTest::lt )); | |
605 IfNode *iff = (IfNode*)gvn->register_new_node_with_optimizer(new (phase->C, 2) IfNode( top_if->in(0), boo, PROB_UNLIKELY_MAG(5), top_if->_fcnt )); | |
606 Node *if_min= gvn->register_new_node_with_optimizer(new (phase->C, 1) IfTrueNode (iff)); | |
607 Node *ifF = gvn->register_new_node_with_optimizer(new (phase->C, 1) IfFalseNode(iff)); | |
608 // min test | |
609 cmp = gvn->register_new_node_with_optimizer(new (phase->C, 3) CmpINode( convf2i, max )); | |
610 boo = gvn->register_new_node_with_optimizer(new (phase->C, 2) BoolNode( cmp, BoolTest::gt )); | |
611 iff = (IfNode*)gvn->register_new_node_with_optimizer(new (phase->C, 2) IfNode( ifF, boo, PROB_UNLIKELY_MAG(5), bot_if->_fcnt )); | |
612 Node *if_max= gvn->register_new_node_with_optimizer(new (phase->C, 1) IfTrueNode (iff)); | |
613 ifF = gvn->register_new_node_with_optimizer(new (phase->C, 1) IfFalseNode(iff)); | |
614 // update input edges to region node | |
615 set_req_X( min_idx, if_min, gvn ); | |
616 set_req_X( max_idx, if_max, gvn ); | |
617 set_req_X( val_idx, ifF, gvn ); | |
618 // remove unnecessary 'LShiftI; RShiftI' idiom | |
619 gvn->hash_delete(phi); | |
620 phi->set_req_X( val_idx, convf2i, gvn ); | |
621 gvn->hash_find_insert(phi); | |
622 // Return transformed region node | |
623 return this; | |
624 } | |
625 } | |
626 } | |
627 } | |
628 } | |
629 } | |
630 } | |
631 | |
632 return NULL; | |
633 } | |
634 | |
635 | |
636 | |
637 const RegMask &RegionNode::out_RegMask() const { | |
638 return RegMask::Empty; | |
639 } | |
640 | |
641 // Find the one non-null required input. RegionNode only | |
642 Node *Node::nonnull_req() const { | |
643 assert( is_Region(), "" ); | |
644 for( uint i = 1; i < _cnt; i++ ) | |
645 if( in(i) ) | |
646 return in(i); | |
647 ShouldNotReachHere(); | |
648 return NULL; | |
649 } | |
650 | |
651 | |
652 //============================================================================= | |
653 // note that these functions assume that the _adr_type field is flattened | |
654 uint PhiNode::hash() const { | |
655 const Type* at = _adr_type; | |
656 return TypeNode::hash() + (at ? at->hash() : 0); | |
657 } | |
658 uint PhiNode::cmp( const Node &n ) const { | |
659 return TypeNode::cmp(n) && _adr_type == ((PhiNode&)n)._adr_type; | |
660 } | |
661 static inline | |
662 const TypePtr* flatten_phi_adr_type(const TypePtr* at) { | |
663 if (at == NULL || at == TypePtr::BOTTOM) return at; | |
664 return Compile::current()->alias_type(at)->adr_type(); | |
665 } | |
666 | |
667 //----------------------------make--------------------------------------------- | |
668 // create a new phi with edges matching r and set (initially) to x | |
669 PhiNode* PhiNode::make(Node* r, Node* x, const Type *t, const TypePtr* at) { | |
670 uint preds = r->req(); // Number of predecessor paths | |
671 assert(t != Type::MEMORY || at == flatten_phi_adr_type(at), "flatten at"); | |
672 PhiNode* p = new (Compile::current(), preds) PhiNode(r, t, at); | |
673 for (uint j = 1; j < preds; j++) { | |
674 // Fill in all inputs, except those which the region does not yet have | |
675 if (r->in(j) != NULL) | |
676 p->init_req(j, x); | |
677 } | |
678 return p; | |
679 } | |
680 PhiNode* PhiNode::make(Node* r, Node* x) { | |
681 const Type* t = x->bottom_type(); | |
682 const TypePtr* at = NULL; | |
683 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); | |
684 return make(r, x, t, at); | |
685 } | |
686 PhiNode* PhiNode::make_blank(Node* r, Node* x) { | |
687 const Type* t = x->bottom_type(); | |
688 const TypePtr* at = NULL; | |
689 if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); | |
690 return new (Compile::current(), r->req()) PhiNode(r, t, at); | |
691 } | |
692 | |
693 | |
694 //------------------------slice_memory----------------------------------------- | |
695 // create a new phi with narrowed memory type | |
696 PhiNode* PhiNode::slice_memory(const TypePtr* adr_type) const { | |
697 PhiNode* mem = (PhiNode*) clone(); | |
698 *(const TypePtr**)&mem->_adr_type = adr_type; | |
699 // convert self-loops, or else we get a bad graph | |
700 for (uint i = 1; i < req(); i++) { | |
701 if ((const Node*)in(i) == this) mem->set_req(i, mem); | |
702 } | |
703 mem->verify_adr_type(); | |
704 return mem; | |
705 } | |
706 | |
707 //------------------------verify_adr_type-------------------------------------- | |
708 #ifdef ASSERT | |
709 void PhiNode::verify_adr_type(VectorSet& visited, const TypePtr* at) const { | |
710 if (visited.test_set(_idx)) return; //already visited | |
711 | |
712 // recheck constructor invariants: | |
713 verify_adr_type(false); | |
714 | |
715 // recheck local phi/phi consistency: | |
716 assert(_adr_type == at || _adr_type == TypePtr::BOTTOM, | |
717 "adr_type must be consistent across phi nest"); | |
718 | |
719 // walk around | |
720 for (uint i = 1; i < req(); i++) { | |
721 Node* n = in(i); | |
722 if (n == NULL) continue; | |
723 const Node* np = in(i); | |
724 if (np->is_Phi()) { | |
725 np->as_Phi()->verify_adr_type(visited, at); | |
726 } else if (n->bottom_type() == Type::TOP | |
727 || (n->is_Mem() && n->in(MemNode::Address)->bottom_type() == Type::TOP)) { | |
728 // ignore top inputs | |
729 } else { | |
730 const TypePtr* nat = flatten_phi_adr_type(n->adr_type()); | |
731 // recheck phi/non-phi consistency at leaves: | |
732 assert((nat != NULL) == (at != NULL), ""); | |
733 assert(nat == at || nat == TypePtr::BOTTOM, | |
734 "adr_type must be consistent at leaves of phi nest"); | |
735 } | |
736 } | |
737 } | |
738 | |
739 // Verify a whole nest of phis rooted at this one. | |
740 void PhiNode::verify_adr_type(bool recursive) const { | |
741 if (is_error_reported()) return; // muzzle asserts when debugging an error | |
742 if (Node::in_dump()) return; // muzzle asserts when printing | |
743 | |
744 assert((_type == Type::MEMORY) == (_adr_type != NULL), "adr_type for memory phis only"); | |
745 | |
746 if (!VerifyAliases) return; // verify thoroughly only if requested | |
747 | |
748 assert(_adr_type == flatten_phi_adr_type(_adr_type), | |
749 "Phi::adr_type must be pre-normalized"); | |
750 | |
751 if (recursive) { | |
752 VectorSet visited(Thread::current()->resource_area()); | |
753 verify_adr_type(visited, _adr_type); | |
754 } | |
755 } | |
756 #endif | |
757 | |
758 | |
759 //------------------------------Value------------------------------------------ | |
760 // Compute the type of the PhiNode | |
761 const Type *PhiNode::Value( PhaseTransform *phase ) const { | |
762 Node *r = in(0); // RegionNode | |
763 if( !r ) // Copy or dead | |
764 return in(1) ? phase->type(in(1)) : Type::TOP; | |
765 | |
766 // Note: During parsing, phis are often transformed before their regions. | |
767 // This means we have to use type_or_null to defend against untyped regions. | |
768 if( phase->type_or_null(r) == Type::TOP ) // Dead code? | |
769 return Type::TOP; | |
770 | |
771 // Check for trip-counted loop. If so, be smarter. | |
772 CountedLoopNode *l = r->is_CountedLoop() ? r->as_CountedLoop() : NULL; | |
773 if( l && l->can_be_counted_loop(phase) && | |
774 ((const Node*)l->phi() == this) ) { // Trip counted loop! | |
775 // protect against init_trip() or limit() returning NULL | |
776 const Node *init = l->init_trip(); | |
777 const Node *limit = l->limit(); | |
778 if( init != NULL && limit != NULL && l->stride_is_con() ) { | |
779 const TypeInt *lo = init ->bottom_type()->isa_int(); | |
780 const TypeInt *hi = limit->bottom_type()->isa_int(); | |
781 if( lo && hi ) { // Dying loops might have TOP here | |
782 int stride = l->stride_con(); | |
783 if( stride < 0 ) { // Down-counter loop | |
784 const TypeInt *tmp = lo; lo = hi; hi = tmp; | |
785 stride = -stride; | |
786 } | |
787 if( lo->_hi < hi->_lo ) // Reversed endpoints are well defined :-( | |
788 return TypeInt::make(lo->_lo,hi->_hi,3); | |
789 } | |
790 } | |
791 } | |
792 | |
793 // Until we have harmony between classes and interfaces in the type | |
794 // lattice, we must tread carefully around phis which implicitly | |
795 // convert the one to the other. | |
796 const TypeInstPtr* ttip = _type->isa_instptr(); | |
797 bool is_intf = false; | |
798 if (ttip != NULL) { | |
799 ciKlass* k = ttip->klass(); | |
800 if (k->is_loaded() && k->is_interface()) | |
801 is_intf = true; | |
802 } | |
803 | |
804 // Default case: merge all inputs | |
805 const Type *t = Type::TOP; // Merged type starting value | |
806 for (uint i = 1; i < req(); ++i) {// For all paths in | |
807 // Reachable control path? | |
808 if (r->in(i) && phase->type(r->in(i)) == Type::CONTROL) { | |
809 const Type* ti = phase->type(in(i)); | |
810 // We assume that each input of an interface-valued Phi is a true | |
811 // subtype of that interface. This might not be true of the meet | |
812 // of all the input types. The lattice is not distributive in | |
813 // such cases. Ward off asserts in type.cpp by refusing to do | |
814 // meets between interfaces and proper classes. | |
815 const TypeInstPtr* tiip = ti->isa_instptr(); | |
816 if (tiip) { | |
817 bool ti_is_intf = false; | |
818 ciKlass* k = tiip->klass(); | |
819 if (k->is_loaded() && k->is_interface()) | |
820 ti_is_intf = true; | |
821 if (is_intf != ti_is_intf) | |
822 { t = _type; break; } | |
823 } | |
824 t = t->meet(ti); | |
825 } | |
826 } | |
827 | |
828 // The worst-case type (from ciTypeFlow) should be consistent with "t". | |
829 // That is, we expect that "t->higher_equal(_type)" holds true. | |
830 // There are various exceptions: | |
831 // - Inputs which are phis might in fact be widened unnecessarily. | |
832 // For example, an input might be a widened int while the phi is a short. | |
833 // - Inputs might be BotPtrs but this phi is dependent on a null check, | |
834 // and postCCP has removed the cast which encodes the result of the check. | |
835 // - The type of this phi is an interface, and the inputs are classes. | |
836 // - Value calls on inputs might produce fuzzy results. | |
837 // (Occurrences of this case suggest improvements to Value methods.) | |
838 // | |
839 // It is not possible to see Type::BOTTOM values as phi inputs, | |
840 // because the ciTypeFlow pre-pass produces verifier-quality types. | |
841 const Type* ft = t->filter(_type); // Worst case type | |
842 | |
843 #ifdef ASSERT | |
844 // The following logic has been moved into TypeOopPtr::filter. | |
845 const Type* jt = t->join(_type); | |
846 if( jt->empty() ) { // Emptied out??? | |
847 | |
848 // Check for evil case of 't' being a class and '_type' expecting an | |
849 // interface. This can happen because the bytecodes do not contain | |
850 // enough type info to distinguish a Java-level interface variable | |
851 // from a Java-level object variable. If we meet 2 classes which | |
852 // both implement interface I, but their meet is at 'j/l/O' which | |
853 // doesn't implement I, we have no way to tell if the result should | |
854 // be 'I' or 'j/l/O'. Thus we'll pick 'j/l/O'. If this then flows | |
855 // into a Phi which "knows" it's an Interface type we'll have to | |
856 // uplift the type. | |
857 if( !t->empty() && ttip && ttip->is_loaded() && ttip->klass()->is_interface() ) | |
858 { assert(ft == _type, ""); } // Uplift to interface | |
859 // Otherwise it's something stupid like non-overlapping int ranges | |
860 // found on dying counted loops. | |
861 else | |
862 { assert(ft == Type::TOP, ""); } // Canonical empty value | |
863 } | |
864 | |
865 else { | |
866 | |
867 // If we have an interface-typed Phi and we narrow to a class type, the join | |
868 // should report back the class. However, if we have a J/L/Object | |
869 // class-typed Phi and an interface flows in, it's possible that the meet & | |
870 // join report an interface back out. This isn't possible but happens | |
871 // because the type system doesn't interact well with interfaces. | |
872 const TypeInstPtr *jtip = jt->isa_instptr(); | |
873 if( jtip && ttip ) { | |
874 if( jtip->is_loaded() && jtip->klass()->is_interface() && | |
875 ttip->is_loaded() && !ttip->klass()->is_interface() ) | |
876 // Happens in a CTW of rt.jar, 320-341, no extra flags | |
877 { assert(ft == ttip->cast_to_ptr_type(jtip->ptr()), ""); jt = ft; } | |
878 } | |
879 if (jt != ft && jt->base() == ft->base()) { | |
880 if (jt->isa_int() && | |
881 jt->is_int()->_lo == ft->is_int()->_lo && | |
882 jt->is_int()->_hi == ft->is_int()->_hi) | |
883 jt = ft; | |
884 if (jt->isa_long() && | |
885 jt->is_long()->_lo == ft->is_long()->_lo && | |
886 jt->is_long()->_hi == ft->is_long()->_hi) | |
887 jt = ft; | |
888 } | |
889 if (jt != ft) { | |
890 tty->print("merge type: "); t->dump(); tty->cr(); | |
891 tty->print("kill type: "); _type->dump(); tty->cr(); | |
892 tty->print("join type: "); jt->dump(); tty->cr(); | |
893 tty->print("filter type: "); ft->dump(); tty->cr(); | |
894 } | |
895 assert(jt == ft, ""); | |
896 } | |
897 #endif //ASSERT | |
898 | |
899 // Deal with conversion problems found in data loops. | |
900 ft = phase->saturate(ft, phase->type_or_null(this), _type); | |
901 | |
902 return ft; | |
903 } | |
904 | |
905 | |
906 //------------------------------is_diamond_phi--------------------------------- | |
907 // Does this Phi represent a simple well-shaped diamond merge? Return the | |
908 // index of the true path or 0 otherwise. | |
909 int PhiNode::is_diamond_phi() const { | |
910 // Check for a 2-path merge | |
911 Node *region = in(0); | |
912 if( !region ) return 0; | |
913 if( region->req() != 3 ) return 0; | |
914 if( req() != 3 ) return 0; | |
915 // Check that both paths come from the same If | |
916 Node *ifp1 = region->in(1); | |
917 Node *ifp2 = region->in(2); | |
918 if( !ifp1 || !ifp2 ) return 0; | |
919 Node *iff = ifp1->in(0); | |
920 if( !iff || !iff->is_If() ) return 0; | |
921 if( iff != ifp2->in(0) ) return 0; | |
922 // Check for a proper bool/cmp | |
923 const Node *b = iff->in(1); | |
924 if( !b->is_Bool() ) return 0; | |
925 const Node *cmp = b->in(1); | |
926 if( !cmp->is_Cmp() ) return 0; | |
927 | |
928 // Check for branching opposite expected | |
929 if( ifp2->Opcode() == Op_IfTrue ) { | |
930 assert( ifp1->Opcode() == Op_IfFalse, "" ); | |
931 return 2; | |
932 } else { | |
933 assert( ifp1->Opcode() == Op_IfTrue, "" ); | |
934 return 1; | |
935 } | |
936 } | |
937 | |
938 //----------------------------check_cmove_id----------------------------------- | |
939 // Check for CMove'ing a constant after comparing against the constant. | |
940 // Happens all the time now, since if we compare equality vs a constant in | |
941 // the parser, we "know" the variable is constant on one path and we force | |
942 // it. Thus code like "if( x==0 ) {/*EMPTY*/}" ends up inserting a | |
943 // conditional move: "x = (x==0)?0:x;". Yucko. This fix is slightly more | |
944 // general in that we don't need constants. Since CMove's are only inserted | |
945 // in very special circumstances, we do it here on generic Phi's. | |
946 Node* PhiNode::is_cmove_id(PhaseTransform* phase, int true_path) { | |
947 assert(true_path !=0, "only diamond shape graph expected"); | |
948 | |
949 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: | |
950 // phi->region->if_proj->ifnode->bool->cmp | |
951 Node* region = in(0); | |
952 Node* iff = region->in(1)->in(0); | |
953 BoolNode* b = iff->in(1)->as_Bool(); | |
954 Node* cmp = b->in(1); | |
955 Node* tval = in(true_path); | |
956 Node* fval = in(3-true_path); | |
957 Node* id = CMoveNode::is_cmove_id(phase, cmp, tval, fval, b); | |
958 if (id == NULL) | |
959 return NULL; | |
960 | |
961 // Either value might be a cast that depends on a branch of 'iff'. | |
962 // Since the 'id' value will float free of the diamond, either | |
963 // decast or return failure. | |
964 Node* ctl = id->in(0); | |
965 if (ctl != NULL && ctl->in(0) == iff) { | |
966 if (id->is_ConstraintCast()) { | |
967 return id->in(1); | |
968 } else { | |
969 // Don't know how to disentangle this value. | |
970 return NULL; | |
971 } | |
972 } | |
973 | |
974 return id; | |
975 } | |
976 | |
977 //------------------------------Identity--------------------------------------- | |
978 // Check for Region being Identity. | |
979 Node *PhiNode::Identity( PhaseTransform *phase ) { | |
980 // Check for no merging going on | |
981 // (There used to be special-case code here when this->region->is_Loop. | |
982 // It would check for a tributary phi on the backedge that the main phi | |
983 // trivially, perhaps with a single cast. The unique_input method | |
984 // does all this and more, by reducing such tributaries to 'this'.) | |
985 Node* uin = unique_input(phase); | |
986 if (uin != NULL) { | |
987 return uin; | |
988 } | |
989 | |
990 int true_path = is_diamond_phi(); | |
991 if (true_path != 0) { | |
992 Node* id = is_cmove_id(phase, true_path); | |
993 if (id != NULL) return id; | |
994 } | |
995 | |
996 return this; // No identity | |
997 } | |
998 | |
999 //-----------------------------unique_input------------------------------------ | |
1000 // Find the unique value, discounting top, self-loops, and casts. | |
1001 // Return top if there are no inputs, and self if there are multiple. | |
1002 Node* PhiNode::unique_input(PhaseTransform* phase) { | |
1003 // 1) One unique direct input, or | |
1004 // 2) some of the inputs have an intervening ConstraintCast and | |
1005 // the type of input is the same or sharper (more specific) | |
1006 // than the phi's type. | |
1007 // 3) an input is a self loop | |
1008 // | |
1009 // 1) input or 2) input or 3) input __ | |
1010 // / \ / \ \ / \ | |
1011 // \ / | cast phi cast | |
1012 // phi \ / / \ / | |
1013 // phi / -- | |
1014 | |
1015 Node* r = in(0); // RegionNode | |
1016 if (r == NULL) return in(1); // Already degraded to a Copy | |
1017 Node* uncasted_input = NULL; // The unique uncasted input (ConstraintCasts removed) | |
1018 Node* direct_input = NULL; // The unique direct input | |
1019 | |
1020 for (uint i = 1, cnt = req(); i < cnt; ++i) { | |
1021 Node* rc = r->in(i); | |
1022 if (rc == NULL || phase->type(rc) == Type::TOP) | |
1023 continue; // ignore unreachable control path | |
1024 Node* n = in(i); | |
1025 Node* un = n->uncast(); | |
1026 if (un == NULL || un == this || phase->type(un) == Type::TOP) { | |
1027 continue; // ignore if top, or in(i) and "this" are in a data cycle | |
1028 } | |
1029 // Check for a unique uncasted input | |
1030 if (uncasted_input == NULL) { | |
1031 uncasted_input = un; | |
1032 } else if (uncasted_input != un) { | |
1033 uncasted_input = NodeSentinel; // no unique uncasted input | |
1034 } | |
1035 // Check for a unique direct input | |
1036 if (direct_input == NULL) { | |
1037 direct_input = n; | |
1038 } else if (direct_input != n) { | |
1039 direct_input = NodeSentinel; // no unique direct input | |
1040 } | |
1041 } | |
1042 if (direct_input == NULL) { | |
1043 return phase->C->top(); // no inputs | |
1044 } | |
1045 assert(uncasted_input != NULL,""); | |
1046 | |
1047 if (direct_input != NodeSentinel) { | |
1048 return direct_input; // one unique direct input | |
1049 } | |
1050 if (uncasted_input != NodeSentinel && | |
1051 phase->type(uncasted_input)->higher_equal(type())) { | |
1052 return uncasted_input; // one unique uncasted input | |
1053 } | |
1054 | |
1055 // Nothing. | |
1056 return NULL; | |
1057 } | |
1058 | |
1059 //------------------------------is_x2logic------------------------------------- | |
1060 // Check for simple convert-to-boolean pattern | |
1061 // If:(C Bool) Region:(IfF IfT) Phi:(Region 0 1) | |
1062 // Convert Phi to an ConvIB. | |
1063 static Node *is_x2logic( PhaseGVN *phase, PhiNode *phi, int true_path ) { | |
1064 assert(true_path !=0, "only diamond shape graph expected"); | |
1065 // Convert the true/false index into an expected 0/1 return. | |
1066 // Map 2->0 and 1->1. | |
1067 int flipped = 2-true_path; | |
1068 | |
1069 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: | |
1070 // phi->region->if_proj->ifnode->bool->cmp | |
1071 Node *region = phi->in(0); | |
1072 Node *iff = region->in(1)->in(0); | |
1073 BoolNode *b = (BoolNode*)iff->in(1); | |
1074 const CmpNode *cmp = (CmpNode*)b->in(1); | |
1075 | |
1076 Node *zero = phi->in(1); | |
1077 Node *one = phi->in(2); | |
1078 const Type *tzero = phase->type( zero ); | |
1079 const Type *tone = phase->type( one ); | |
1080 | |
1081 // Check for compare vs 0 | |
1082 const Type *tcmp = phase->type(cmp->in(2)); | |
1083 if( tcmp != TypeInt::ZERO && tcmp != TypePtr::NULL_PTR ) { | |
1084 // Allow cmp-vs-1 if the other input is bounded by 0-1 | |
1085 if( !(tcmp == TypeInt::ONE && phase->type(cmp->in(1)) == TypeInt::BOOL) ) | |
1086 return NULL; | |
1087 flipped = 1-flipped; // Test is vs 1 instead of 0! | |
1088 } | |
1089 | |
1090 // Check for setting zero/one opposite expected | |
1091 if( tzero == TypeInt::ZERO ) { | |
1092 if( tone == TypeInt::ONE ) { | |
1093 } else return NULL; | |
1094 } else if( tzero == TypeInt::ONE ) { | |
1095 if( tone == TypeInt::ZERO ) { | |
1096 flipped = 1-flipped; | |
1097 } else return NULL; | |
1098 } else return NULL; | |
1099 | |
1100 // Check for boolean test backwards | |
1101 if( b->_test._test == BoolTest::ne ) { | |
1102 } else if( b->_test._test == BoolTest::eq ) { | |
1103 flipped = 1-flipped; | |
1104 } else return NULL; | |
1105 | |
1106 // Build int->bool conversion | |
1107 Node *n = new (phase->C, 2) Conv2BNode( cmp->in(1) ); | |
1108 if( flipped ) | |
1109 n = new (phase->C, 3) XorINode( phase->transform(n), phase->intcon(1) ); | |
1110 | |
1111 return n; | |
1112 } | |
1113 | |
1114 //------------------------------is_cond_add------------------------------------ | |
1115 // Check for simple conditional add pattern: "(P < Q) ? X+Y : X;" | |
1116 // To be profitable the control flow has to disappear; there can be no other | |
1117 // values merging here. We replace the test-and-branch with: | |
1118 // "(sgn(P-Q))&Y) + X". Basically, convert "(P < Q)" into 0 or -1 by | |
1119 // moving the carry bit from (P-Q) into a register with 'sbb EAX,EAX'. | |
1120 // Then convert Y to 0-or-Y and finally add. | |
1121 // This is a key transform for SpecJava _201_compress. | |
1122 static Node* is_cond_add(PhaseGVN *phase, PhiNode *phi, int true_path) { | |
1123 assert(true_path !=0, "only diamond shape graph expected"); | |
1124 | |
1125 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: | |
1126 // phi->region->if_proj->ifnode->bool->cmp | |
1127 RegionNode *region = (RegionNode*)phi->in(0); | |
1128 Node *iff = region->in(1)->in(0); | |
1129 BoolNode* b = iff->in(1)->as_Bool(); | |
1130 const CmpNode *cmp = (CmpNode*)b->in(1); | |
1131 | |
1132 // Make sure only merging this one phi here | |
1133 if (region->has_unique_phi() != phi) return NULL; | |
1134 | |
1135 // Make sure each arm of the diamond has exactly one output, which we assume | |
1136 // is the region. Otherwise, the control flow won't disappear. | |
1137 if (region->in(1)->outcnt() != 1) return NULL; | |
1138 if (region->in(2)->outcnt() != 1) return NULL; | |
1139 | |
1140 // Check for "(P < Q)" of type signed int | |
1141 if (b->_test._test != BoolTest::lt) return NULL; | |
1142 if (cmp->Opcode() != Op_CmpI) return NULL; | |
1143 | |
1144 Node *p = cmp->in(1); | |
1145 Node *q = cmp->in(2); | |
1146 Node *n1 = phi->in( true_path); | |
1147 Node *n2 = phi->in(3-true_path); | |
1148 | |
1149 int op = n1->Opcode(); | |
1150 if( op != Op_AddI // Need zero as additive identity | |
1151 /*&&op != Op_SubI && | |
1152 op != Op_AddP && | |
1153 op != Op_XorI && | |
1154 op != Op_OrI*/ ) | |
1155 return NULL; | |
1156 | |
1157 Node *x = n2; | |
1158 Node *y = n1->in(1); | |
1159 if( n2 == n1->in(1) ) { | |
1160 y = n1->in(2); | |
1161 } else if( n2 == n1->in(1) ) { | |
1162 } else return NULL; | |
1163 | |
1164 // Not so profitable if compare and add are constants | |
1165 if( q->is_Con() && phase->type(q) != TypeInt::ZERO && y->is_Con() ) | |
1166 return NULL; | |
1167 | |
1168 Node *cmplt = phase->transform( new (phase->C, 3) CmpLTMaskNode(p,q) ); | |
1169 Node *j_and = phase->transform( new (phase->C, 3) AndINode(cmplt,y) ); | |
1170 return new (phase->C, 3) AddINode(j_and,x); | |
1171 } | |
1172 | |
1173 //------------------------------is_absolute------------------------------------ | |
1174 // Check for absolute value. | |
1175 static Node* is_absolute( PhaseGVN *phase, PhiNode *phi_root, int true_path) { | |
1176 assert(true_path !=0, "only diamond shape graph expected"); | |
1177 | |
1178 int cmp_zero_idx = 0; // Index of compare input where to look for zero | |
1179 int phi_x_idx = 0; // Index of phi input where to find naked x | |
1180 | |
1181 // ABS ends with the merge of 2 control flow paths. | |
1182 // Find the false path from the true path. With only 2 inputs, 3 - x works nicely. | |
1183 int false_path = 3 - true_path; | |
1184 | |
1185 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: | |
1186 // phi->region->if_proj->ifnode->bool->cmp | |
1187 BoolNode *bol = phi_root->in(0)->in(1)->in(0)->in(1)->as_Bool(); | |
1188 | |
1189 // Check bool sense | |
1190 switch( bol->_test._test ) { | |
1191 case BoolTest::lt: cmp_zero_idx = 1; phi_x_idx = true_path; break; | |
1192 case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break; | |
1193 case BoolTest::gt: cmp_zero_idx = 2; phi_x_idx = true_path; break; | |
1194 case BoolTest::ge: cmp_zero_idx = 1; phi_x_idx = false_path; break; | |
1195 default: return NULL; break; | |
1196 } | |
1197 | |
1198 // Test is next | |
1199 Node *cmp = bol->in(1); | |
1200 const Type *tzero = NULL; | |
1201 switch( cmp->Opcode() ) { | |
1202 case Op_CmpF: tzero = TypeF::ZERO; break; // Float ABS | |
1203 case Op_CmpD: tzero = TypeD::ZERO; break; // Double ABS | |
1204 default: return NULL; | |
1205 } | |
1206 | |
1207 // Find zero input of compare; the other input is being abs'd | |
1208 Node *x = NULL; | |
1209 bool flip = false; | |
1210 if( phase->type(cmp->in(cmp_zero_idx)) == tzero ) { | |
1211 x = cmp->in(3 - cmp_zero_idx); | |
1212 } else if( phase->type(cmp->in(3 - cmp_zero_idx)) == tzero ) { | |
1213 // The test is inverted, we should invert the result... | |
1214 x = cmp->in(cmp_zero_idx); | |
1215 flip = true; | |
1216 } else { | |
1217 return NULL; | |
1218 } | |
1219 | |
1220 // Next get the 2 pieces being selected, one is the original value | |
1221 // and the other is the negated value. | |
1222 if( phi_root->in(phi_x_idx) != x ) return NULL; | |
1223 | |
1224 // Check other phi input for subtract node | |
1225 Node *sub = phi_root->in(3 - phi_x_idx); | |
1226 | |
1227 // Allow only Sub(0,X) and fail out for all others; Neg is not OK | |
1228 if( tzero == TypeF::ZERO ) { | |
1229 if( sub->Opcode() != Op_SubF || | |
1230 sub->in(2) != x || | |
1231 phase->type(sub->in(1)) != tzero ) return NULL; | |
1232 x = new (phase->C, 2) AbsFNode(x); | |
1233 if (flip) { | |
1234 x = new (phase->C, 3) SubFNode(sub->in(1), phase->transform(x)); | |
1235 } | |
1236 } else { | |
1237 if( sub->Opcode() != Op_SubD || | |
1238 sub->in(2) != x || | |
1239 phase->type(sub->in(1)) != tzero ) return NULL; | |
1240 x = new (phase->C, 2) AbsDNode(x); | |
1241 if (flip) { | |
1242 x = new (phase->C, 3) SubDNode(sub->in(1), phase->transform(x)); | |
1243 } | |
1244 } | |
1245 | |
1246 return x; | |
1247 } | |
1248 | |
1249 //------------------------------split_once------------------------------------- | |
1250 // Helper for split_flow_path | |
1251 static void split_once(PhaseIterGVN *igvn, Node *phi, Node *val, Node *n, Node *newn) { | |
1252 igvn->hash_delete(n); // Remove from hash before hacking edges | |
1253 | |
1254 uint j = 1; | |
1255 for( uint i = phi->req()-1; i > 0; i-- ) { | |
1256 if( phi->in(i) == val ) { // Found a path with val? | |
1257 // Add to NEW Region/Phi, no DU info | |
1258 newn->set_req( j++, n->in(i) ); | |
1259 // Remove from OLD Region/Phi | |
1260 n->del_req(i); | |
1261 } | |
1262 } | |
1263 | |
1264 // Register the new node but do not transform it. Cannot transform until the | |
1265 // entire Region/Phi conglerate has been hacked as a single huge transform. | |
1266 igvn->register_new_node_with_optimizer( newn ); | |
1267 // Now I can point to the new node. | |
1268 n->add_req(newn); | |
1269 igvn->_worklist.push(n); | |
1270 } | |
1271 | |
1272 //------------------------------split_flow_path-------------------------------- | |
1273 // Check for merging identical values and split flow paths | |
1274 static Node* split_flow_path(PhaseGVN *phase, PhiNode *phi) { | |
1275 BasicType bt = phi->type()->basic_type(); | |
1276 if( bt == T_ILLEGAL || type2size[bt] <= 0 ) | |
1277 return NULL; // Bail out on funny non-value stuff | |
1278 if( phi->req() <= 3 ) // Need at least 2 matched inputs and a | |
1279 return NULL; // third unequal input to be worth doing | |
1280 | |
1281 // Scan for a constant | |
1282 uint i; | |
1283 for( i = 1; i < phi->req()-1; i++ ) { | |
1284 Node *n = phi->in(i); | |
1285 if( !n ) return NULL; | |
1286 if( phase->type(n) == Type::TOP ) return NULL; | |
1287 if( n->Opcode() == Op_ConP ) | |
1288 break; | |
1289 } | |
1290 if( i >= phi->req() ) // Only split for constants | |
1291 return NULL; | |
1292 | |
1293 Node *val = phi->in(i); // Constant to split for | |
1294 uint hit = 0; // Number of times it occurs | |
1295 | |
1296 for( ; i < phi->req(); i++ ){ // Count occurances of constant | |
1297 Node *n = phi->in(i); | |
1298 if( !n ) return NULL; | |
1299 if( phase->type(n) == Type::TOP ) return NULL; | |
1300 if( phi->in(i) == val ) | |
1301 hit++; | |
1302 } | |
1303 | |
1304 if( hit <= 1 || // Make sure we find 2 or more | |
1305 hit == phi->req()-1 ) // and not ALL the same value | |
1306 return NULL; | |
1307 | |
1308 // Now start splitting out the flow paths that merge the same value. | |
1309 // Split first the RegionNode. | |
1310 PhaseIterGVN *igvn = phase->is_IterGVN(); | |
1311 Node *r = phi->region(); | |
1312 RegionNode *newr = new (phase->C, hit+1) RegionNode(hit+1); | |
1313 split_once(igvn, phi, val, r, newr); | |
1314 | |
1315 // Now split all other Phis than this one | |
1316 for (DUIterator_Fast kmax, k = r->fast_outs(kmax); k < kmax; k++) { | |
1317 Node* phi2 = r->fast_out(k); | |
1318 if( phi2->is_Phi() && phi2->as_Phi() != phi ) { | |
1319 PhiNode *newphi = PhiNode::make_blank(newr, phi2); | |
1320 split_once(igvn, phi, val, phi2, newphi); | |
1321 } | |
1322 } | |
1323 | |
1324 // Clean up this guy | |
1325 igvn->hash_delete(phi); | |
1326 for( i = phi->req()-1; i > 0; i-- ) { | |
1327 if( phi->in(i) == val ) { | |
1328 phi->del_req(i); | |
1329 } | |
1330 } | |
1331 phi->add_req(val); | |
1332 | |
1333 return phi; | |
1334 } | |
1335 | |
1336 //============================================================================= | |
1337 //------------------------------simple_data_loop_check------------------------- | |
1338 // Try to determing if the phi node in a simple safe/unsafe data loop. | |
1339 // Returns: | |
1340 // enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop }; | |
1341 // Safe - safe case when the phi and it's inputs reference only safe data | |
1342 // nodes; | |
1343 // Unsafe - the phi and it's inputs reference unsafe data nodes but there | |
1344 // is no reference back to the phi - need a graph walk | |
1345 // to determine if it is in a loop; | |
1346 // UnsafeLoop - unsafe case when the phi references itself directly or through | |
1347 // unsafe data node. | |
1348 // Note: a safe data node is a node which could/never reference itself during | |
1349 // GVN transformations. For now it is Con, Proj, Phi, CastPP, CheckCastPP. | |
1350 // I mark Phi nodes as safe node not only because they can reference itself | |
1351 // but also to prevent mistaking the fallthrough case inside an outer loop | |
1352 // as dead loop when the phi references itselfs through an other phi. | |
1353 PhiNode::LoopSafety PhiNode::simple_data_loop_check(Node *in) const { | |
1354 // It is unsafe loop if the phi node references itself directly. | |
1355 if (in == (Node*)this) | |
1356 return UnsafeLoop; // Unsafe loop | |
1357 // Unsafe loop if the phi node references itself through an unsafe data node. | |
1358 // Exclude cases with null inputs or data nodes which could reference | |
1359 // itself (safe for dead loops). | |
1360 if (in != NULL && !in->is_dead_loop_safe()) { | |
1361 // Check inputs of phi's inputs also. | |
1362 // It is much less expensive then full graph walk. | |
1363 uint cnt = in->req(); | |
1364 for (uint i = 1; i < cnt; ++i) { | |
1365 Node* m = in->in(i); | |
1366 if (m == (Node*)this) | |
1367 return UnsafeLoop; // Unsafe loop | |
1368 if (m != NULL && !m->is_dead_loop_safe()) { | |
1369 // Check the most common case (about 30% of all cases): | |
1370 // phi->Load/Store->AddP->(ConP ConP Con)/(Parm Parm Con). | |
1371 Node *m1 = (m->is_AddP() && m->req() > 3) ? m->in(1) : NULL; | |
1372 if (m1 == (Node*)this) | |
1373 return UnsafeLoop; // Unsafe loop | |
1374 if (m1 != NULL && m1 == m->in(2) && | |
1375 m1->is_dead_loop_safe() && m->in(3)->is_Con()) { | |
1376 continue; // Safe case | |
1377 } | |
1378 // The phi references an unsafe node - need full analysis. | |
1379 return Unsafe; | |
1380 } | |
1381 } | |
1382 } | |
1383 return Safe; // Safe case - we can optimize the phi node. | |
1384 } | |
1385 | |
1386 //------------------------------is_unsafe_data_reference----------------------- | |
1387 // If phi can be reached through the data input - it is data loop. | |
1388 bool PhiNode::is_unsafe_data_reference(Node *in) const { | |
1389 assert(req() > 1, ""); | |
1390 // First, check simple cases when phi references itself directly or | |
1391 // through an other node. | |
1392 LoopSafety safety = simple_data_loop_check(in); | |
1393 if (safety == UnsafeLoop) | |
1394 return true; // phi references itself - unsafe loop | |
1395 else if (safety == Safe) | |
1396 return false; // Safe case - phi could be replaced with the unique input. | |
1397 | |
1398 // Unsafe case when we should go through data graph to determine | |
1399 // if the phi references itself. | |
1400 | |
1401 ResourceMark rm; | |
1402 | |
1403 Arena *a = Thread::current()->resource_area(); | |
1404 Node_List nstack(a); | |
1405 VectorSet visited(a); | |
1406 | |
1407 nstack.push(in); // Start with unique input. | |
1408 visited.set(in->_idx); | |
1409 while (nstack.size() != 0) { | |
1410 Node* n = nstack.pop(); | |
1411 uint cnt = n->req(); | |
1412 for (uint i = 1; i < cnt; i++) { // Only data paths | |
1413 Node* m = n->in(i); | |
1414 if (m == (Node*)this) { | |
1415 return true; // Data loop | |
1416 } | |
1417 if (m != NULL && !m->is_dead_loop_safe()) { // Only look for unsafe cases. | |
1418 if (!visited.test_set(m->_idx)) | |
1419 nstack.push(m); | |
1420 } | |
1421 } | |
1422 } | |
1423 return false; // The phi is not reachable from its inputs | |
1424 } | |
1425 | |
1426 | |
1427 //------------------------------Ideal------------------------------------------ | |
1428 // Return a node which is more "ideal" than the current node. Must preserve | |
1429 // the CFG, but we can still strip out dead paths. | |
1430 Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) { | |
1431 // The next should never happen after 6297035 fix. | |
1432 if( is_copy() ) // Already degraded to a Copy ? | |
1433 return NULL; // No change | |
1434 | |
1435 Node *r = in(0); // RegionNode | |
1436 assert(r->in(0) == NULL || !r->in(0)->is_Root(), "not a specially hidden merge"); | |
1437 | |
1438 // Note: During parsing, phis are often transformed before their regions. | |
1439 // This means we have to use type_or_null to defend against untyped regions. | |
1440 if( phase->type_or_null(r) == Type::TOP ) // Dead code? | |
1441 return NULL; // No change | |
1442 | |
1443 Node *top = phase->C->top(); | |
1444 | |
1445 // The are 2 situations when only one valid phi's input is left | |
1446 // (in addition to Region input). | |
1447 // One: region is not loop - replace phi with this input. | |
1448 // Two: region is loop - replace phi with top since this data path is dead | |
1449 // and we need to break the dead data loop. | |
1450 Node* progress = NULL; // Record if any progress made | |
1451 for( uint j = 1; j < req(); ++j ){ // For all paths in | |
1452 // Check unreachable control paths | |
1453 Node* rc = r->in(j); | |
1454 Node* n = in(j); // Get the input | |
1455 if (rc == NULL || phase->type(rc) == Type::TOP) { | |
1456 if (n != top) { // Not already top? | |
1457 set_req(j, top); // Nuke it down | |
1458 progress = this; // Record progress | |
1459 } | |
1460 } | |
1461 } | |
1462 | |
1463 Node* uin = unique_input(phase); | |
1464 if (uin == top) { // Simplest case: no alive inputs. | |
1465 if (can_reshape) // IGVN transformation | |
1466 return top; | |
1467 else | |
1468 return NULL; // Identity will return TOP | |
1469 } else if (uin != NULL) { | |
1470 // Only one not-NULL unique input path is left. | |
1471 // Determine if this input is backedge of a loop. | |
1472 // (Skip new phis which have no uses and dead regions). | |
1473 if( outcnt() > 0 && r->in(0) != NULL ) { | |
1474 // First, take the short cut when we know it is a loop and | |
1475 // the EntryControl data path is dead. | |
1476 assert(!r->is_Loop() || r->req() == 3, "Loop node should have 3 inputs"); | |
1477 // Then, check if there is a data loop when phi references itself directly | |
1478 // or through other data nodes. | |
1479 if( r->is_Loop() && !phase->eqv_uncast(uin, in(LoopNode::EntryControl)) || | |
1480 !r->is_Loop() && is_unsafe_data_reference(uin) ) { | |
1481 // Break this data loop to avoid creation of a dead loop. | |
1482 if (can_reshape) { | |
1483 return top; | |
1484 } else { | |
1485 // We can't return top if we are in Parse phase - cut inputs only | |
1486 // let Identity to handle the case. | |
1487 replace_edge(uin, top); | |
1488 return NULL; | |
1489 } | |
1490 } | |
1491 } | |
1492 | |
1493 // One unique input. | |
1494 debug_only(Node* ident = Identity(phase)); | |
1495 // The unique input must eventually be detected by the Identity call. | |
1496 #ifdef ASSERT | |
1497 if (ident != uin && !ident->is_top()) { | |
1498 // print this output before failing assert | |
1499 r->dump(3); | |
1500 this->dump(3); | |
1501 ident->dump(); | |
1502 uin->dump(); | |
1503 } | |
1504 #endif | |
1505 assert(ident == uin || ident->is_top(), "Identity must clean this up"); | |
1506 return NULL; | |
1507 } | |
1508 | |
1509 | |
1510 Node* opt = NULL; | |
1511 int true_path = is_diamond_phi(); | |
1512 if( true_path != 0 ) { | |
1513 // Check for CMove'ing identity. If it would be unsafe, | |
1514 // handle it here. In the safe case, let Identity handle it. | |
1515 Node* unsafe_id = is_cmove_id(phase, true_path); | |
1516 if( unsafe_id != NULL && is_unsafe_data_reference(unsafe_id) ) | |
1517 opt = unsafe_id; | |
1518 | |
1519 // Check for simple convert-to-boolean pattern | |
1520 if( opt == NULL ) | |
1521 opt = is_x2logic(phase, this, true_path); | |
1522 | |
1523 // Check for absolute value | |
1524 if( opt == NULL ) | |
1525 opt = is_absolute(phase, this, true_path); | |
1526 | |
1527 // Check for conditional add | |
1528 if( opt == NULL && can_reshape ) | |
1529 opt = is_cond_add(phase, this, true_path); | |
1530 | |
1531 // These 4 optimizations could subsume the phi: | |
1532 // have to check for a dead data loop creation. | |
1533 if( opt != NULL ) { | |
1534 if( opt == unsafe_id || is_unsafe_data_reference(opt) ) { | |
1535 // Found dead loop. | |
1536 if( can_reshape ) | |
1537 return top; | |
1538 // We can't return top if we are in Parse phase - cut inputs only | |
1539 // to stop further optimizations for this phi. Identity will return TOP. | |
1540 assert(req() == 3, "only diamond merge phi here"); | |
1541 set_req(1, top); | |
1542 set_req(2, top); | |
1543 return NULL; | |
1544 } else { | |
1545 return opt; | |
1546 } | |
1547 } | |
1548 } | |
1549 | |
1550 // Check for merging identical values and split flow paths | |
1551 if (can_reshape) { | |
1552 opt = split_flow_path(phase, this); | |
1553 // This optimization only modifies phi - don't need to check for dead loop. | |
1554 assert(opt == NULL || phase->eqv(opt, this), "do not elide phi"); | |
1555 if (opt != NULL) return opt; | |
1556 } | |
1557 | |
1558 if (in(1) != NULL && in(1)->Opcode() == Op_AddP && can_reshape) { | |
1559 // Try to undo Phi of AddP: | |
1560 // (Phi (AddP base base y) (AddP base2 base2 y)) | |
1561 // becomes: | |
1562 // newbase := (Phi base base2) | |
1563 // (AddP newbase newbase y) | |
1564 // | |
1565 // This occurs as a result of unsuccessful split_thru_phi and | |
1566 // interferes with taking advantage of addressing modes. See the | |
1567 // clone_shift_expressions code in matcher.cpp | |
1568 Node* addp = in(1); | |
1569 const Type* type = addp->in(AddPNode::Base)->bottom_type(); | |
1570 Node* y = addp->in(AddPNode::Offset); | |
1571 if (y != NULL && addp->in(AddPNode::Base) == addp->in(AddPNode::Address)) { | |
1572 // make sure that all the inputs are similar to the first one, | |
1573 // i.e. AddP with base == address and same offset as first AddP | |
1574 bool doit = true; | |
1575 for (uint i = 2; i < req(); i++) { | |
1576 if (in(i) == NULL || | |
1577 in(i)->Opcode() != Op_AddP || | |
1578 in(i)->in(AddPNode::Base) != in(i)->in(AddPNode::Address) || | |
1579 in(i)->in(AddPNode::Offset) != y) { | |
1580 doit = false; | |
1581 break; | |
1582 } | |
1583 // Accumulate type for resulting Phi | |
1584 type = type->meet(in(i)->in(AddPNode::Base)->bottom_type()); | |
1585 } | |
1586 Node* base = NULL; | |
1587 if (doit) { | |
1588 // Check for neighboring AddP nodes in a tree. | |
1589 // If they have a base, use that it. | |
1590 for (DUIterator_Fast kmax, k = this->fast_outs(kmax); k < kmax; k++) { | |
1591 Node* u = this->fast_out(k); | |
1592 if (u->is_AddP()) { | |
1593 Node* base2 = u->in(AddPNode::Base); | |
1594 if (base2 != NULL && !base2->is_top()) { | |
1595 if (base == NULL) | |
1596 base = base2; | |
1597 else if (base != base2) | |
1598 { doit = false; break; } | |
1599 } | |
1600 } | |
1601 } | |
1602 } | |
1603 if (doit) { | |
1604 if (base == NULL) { | |
1605 base = new (phase->C, in(0)->req()) PhiNode(in(0), type, NULL); | |
1606 for (uint i = 1; i < req(); i++) { | |
1607 base->init_req(i, in(i)->in(AddPNode::Base)); | |
1608 } | |
1609 phase->is_IterGVN()->register_new_node_with_optimizer(base); | |
1610 } | |
1611 return new (phase->C, 4) AddPNode(base, base, y); | |
1612 } | |
1613 } | |
1614 } | |
1615 | |
1616 // Split phis through memory merges, so that the memory merges will go away. | |
1617 // Piggy-back this transformation on the search for a unique input.... | |
1618 // It will be as if the merged memory is the unique value of the phi. | |
1619 // (Do not attempt this optimization unless parsing is complete. | |
1620 // It would make the parser's memory-merge logic sick.) | |
1621 // (MergeMemNode is not dead_loop_safe - need to check for dead loop.) | |
1622 if (progress == NULL && can_reshape && type() == Type::MEMORY) { | |
1623 // see if this phi should be sliced | |
1624 uint merge_width = 0; | |
1625 bool saw_self = false; | |
1626 for( uint i=1; i<req(); ++i ) {// For all paths in | |
1627 Node *ii = in(i); | |
1628 if (ii->is_MergeMem()) { | |
1629 MergeMemNode* n = ii->as_MergeMem(); | |
1630 merge_width = MAX2(merge_width, n->req()); | |
1631 saw_self = saw_self || phase->eqv(n->base_memory(), this); | |
1632 } | |
1633 } | |
1634 | |
1635 // This restriction is temporarily necessary to ensure termination: | |
1636 if (!saw_self && adr_type() == TypePtr::BOTTOM) merge_width = 0; | |
1637 | |
1638 if (merge_width > Compile::AliasIdxRaw) { | |
1639 // found at least one non-empty MergeMem | |
1640 const TypePtr* at = adr_type(); | |
1641 if (at != TypePtr::BOTTOM) { | |
1642 // Patch the existing phi to select an input from the merge: | |
1643 // Phi:AT1(...MergeMem(m0, m1, m2)...) into | |
1644 // Phi:AT1(...m1...) | |
1645 int alias_idx = phase->C->get_alias_index(at); | |
1646 for (uint i=1; i<req(); ++i) { | |
1647 Node *ii = in(i); | |
1648 if (ii->is_MergeMem()) { | |
1649 MergeMemNode* n = ii->as_MergeMem(); | |
1650 // compress paths and change unreachable cycles to TOP | |
1651 // If not, we can update the input infinitely along a MergeMem cycle | |
1652 // Equivalent code is in MemNode::Ideal_common | |
1653 Node *m = phase->transform(n); | |
1654 // If tranformed to a MergeMem, get the desired slice | |
1655 // Otherwise the returned node represents memory for every slice | |
1656 Node *new_mem = (m->is_MergeMem()) ? | |
1657 m->as_MergeMem()->memory_at(alias_idx) : m; | |
1658 // Update input if it is progress over what we have now | |
1659 if (new_mem != ii) { | |
1660 set_req(i, new_mem); | |
1661 progress = this; | |
1662 } | |
1663 } | |
1664 } | |
1665 } else { | |
1666 // We know that at least one MergeMem->base_memory() == this | |
1667 // (saw_self == true). If all other inputs also references this phi | |
1668 // (directly or through data nodes) - it is dead loop. | |
1669 bool saw_safe_input = false; | |
1670 for (uint j = 1; j < req(); ++j) { | |
1671 Node *n = in(j); | |
1672 if (n->is_MergeMem() && n->as_MergeMem()->base_memory() == this) | |
1673 continue; // skip known cases | |
1674 if (!is_unsafe_data_reference(n)) { | |
1675 saw_safe_input = true; // found safe input | |
1676 break; | |
1677 } | |
1678 } | |
1679 if (!saw_safe_input) | |
1680 return top; // all inputs reference back to this phi - dead loop | |
1681 | |
1682 // Phi(...MergeMem(m0, m1:AT1, m2:AT2)...) into | |
1683 // MergeMem(Phi(...m0...), Phi:AT1(...m1...), Phi:AT2(...m2...)) | |
1684 PhaseIterGVN *igvn = phase->is_IterGVN(); | |
1685 Node* hook = new (phase->C, 1) Node(1); | |
1686 PhiNode* new_base = (PhiNode*) clone(); | |
1687 // Must eagerly register phis, since they participate in loops. | |
1688 if (igvn) { | |
1689 igvn->register_new_node_with_optimizer(new_base); | |
1690 hook->add_req(new_base); | |
1691 } | |
1692 MergeMemNode* result = MergeMemNode::make(phase->C, new_base); | |
1693 for (uint i = 1; i < req(); ++i) { | |
1694 Node *ii = in(i); | |
1695 if (ii->is_MergeMem()) { | |
1696 MergeMemNode* n = ii->as_MergeMem(); | |
1697 for (MergeMemStream mms(result, n); mms.next_non_empty2(); ) { | |
1698 // If we have not seen this slice yet, make a phi for it. | |
1699 bool made_new_phi = false; | |
1700 if (mms.is_empty()) { | |
1701 Node* new_phi = new_base->slice_memory(mms.adr_type(phase->C)); | |
1702 made_new_phi = true; | |
1703 if (igvn) { | |
1704 igvn->register_new_node_with_optimizer(new_phi); | |
1705 hook->add_req(new_phi); | |
1706 } | |
1707 mms.set_memory(new_phi); | |
1708 } | |
1709 Node* phi = mms.memory(); | |
1710 assert(made_new_phi || phi->in(i) == n, "replace the i-th merge by a slice"); | |
1711 phi->set_req(i, mms.memory2()); | |
1712 } | |
1713 } | |
1714 } | |
1715 // Distribute all self-loops. | |
1716 { // (Extra braces to hide mms.) | |
1717 for (MergeMemStream mms(result); mms.next_non_empty(); ) { | |
1718 Node* phi = mms.memory(); | |
1719 for (uint i = 1; i < req(); ++i) { | |
1720 if (phi->in(i) == this) phi->set_req(i, phi); | |
1721 } | |
1722 } | |
1723 } | |
1724 // now transform the new nodes, and return the mergemem | |
1725 for (MergeMemStream mms(result); mms.next_non_empty(); ) { | |
1726 Node* phi = mms.memory(); | |
1727 mms.set_memory(phase->transform(phi)); | |
1728 } | |
1729 if (igvn) { // Unhook. | |
1730 igvn->hash_delete(hook); | |
1731 for (uint i = 1; i < hook->req(); i++) { | |
1732 hook->set_req(i, NULL); | |
1733 } | |
1734 } | |
1735 // Replace self with the result. | |
1736 return result; | |
1737 } | |
1738 } | |
1739 } | |
1740 | |
1741 return progress; // Return any progress | |
1742 } | |
1743 | |
1744 //------------------------------out_RegMask------------------------------------ | |
1745 const RegMask &PhiNode::in_RegMask(uint i) const { | |
1746 return i ? out_RegMask() : RegMask::Empty; | |
1747 } | |
1748 | |
1749 const RegMask &PhiNode::out_RegMask() const { | |
1750 uint ideal_reg = Matcher::base2reg[_type->base()]; | |
1751 assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" ); | |
1752 if( ideal_reg == 0 ) return RegMask::Empty; | |
1753 return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]); | |
1754 } | |
1755 | |
1756 #ifndef PRODUCT | |
1757 void PhiNode::dump_spec(outputStream *st) const { | |
1758 TypeNode::dump_spec(st); | |
1759 if (in(0) != NULL && | |
1760 in(0)->is_CountedLoop() && | |
1761 in(0)->as_CountedLoop()->phi() == this) { | |
1762 st->print(" #tripcount"); | |
1763 } | |
1764 } | |
1765 #endif | |
1766 | |
1767 | |
1768 //============================================================================= | |
1769 const Type *GotoNode::Value( PhaseTransform *phase ) const { | |
1770 // If the input is reachable, then we are executed. | |
1771 // If the input is not reachable, then we are not executed. | |
1772 return phase->type(in(0)); | |
1773 } | |
1774 | |
1775 Node *GotoNode::Identity( PhaseTransform *phase ) { | |
1776 return in(0); // Simple copy of incoming control | |
1777 } | |
1778 | |
1779 const RegMask &GotoNode::out_RegMask() const { | |
1780 return RegMask::Empty; | |
1781 } | |
1782 | |
1783 //============================================================================= | |
1784 const RegMask &JumpNode::out_RegMask() const { | |
1785 return RegMask::Empty; | |
1786 } | |
1787 | |
1788 //============================================================================= | |
1789 const RegMask &JProjNode::out_RegMask() const { | |
1790 return RegMask::Empty; | |
1791 } | |
1792 | |
1793 //============================================================================= | |
1794 const RegMask &CProjNode::out_RegMask() const { | |
1795 return RegMask::Empty; | |
1796 } | |
1797 | |
1798 | |
1799 | |
1800 //============================================================================= | |
1801 | |
1802 uint PCTableNode::hash() const { return Node::hash() + _size; } | |
1803 uint PCTableNode::cmp( const Node &n ) const | |
1804 { return _size == ((PCTableNode&)n)._size; } | |
1805 | |
1806 const Type *PCTableNode::bottom_type() const { | |
1807 const Type** f = TypeTuple::fields(_size); | |
1808 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; | |
1809 return TypeTuple::make(_size, f); | |
1810 } | |
1811 | |
1812 //------------------------------Value------------------------------------------ | |
1813 // Compute the type of the PCTableNode. If reachable it is a tuple of | |
1814 // Control, otherwise the table targets are not reachable | |
1815 const Type *PCTableNode::Value( PhaseTransform *phase ) const { | |
1816 if( phase->type(in(0)) == Type::CONTROL ) | |
1817 return bottom_type(); | |
1818 return Type::TOP; // All paths dead? Then so are we | |
1819 } | |
1820 | |
1821 //------------------------------Ideal------------------------------------------ | |
1822 // Return a node which is more "ideal" than the current node. Strip out | |
1823 // control copies | |
1824 Node *PCTableNode::Ideal(PhaseGVN *phase, bool can_reshape) { | |
1825 return remove_dead_region(phase, can_reshape) ? this : NULL; | |
1826 } | |
1827 | |
1828 //============================================================================= | |
1829 uint JumpProjNode::hash() const { | |
1830 return Node::hash() + _dest_bci; | |
1831 } | |
1832 | |
1833 uint JumpProjNode::cmp( const Node &n ) const { | |
1834 return ProjNode::cmp(n) && | |
1835 _dest_bci == ((JumpProjNode&)n)._dest_bci; | |
1836 } | |
1837 | |
1838 #ifndef PRODUCT | |
1839 void JumpProjNode::dump_spec(outputStream *st) const { | |
1840 ProjNode::dump_spec(st); | |
1841 st->print("@bci %d ",_dest_bci); | |
1842 } | |
1843 #endif | |
1844 | |
1845 //============================================================================= | |
1846 //------------------------------Value------------------------------------------ | |
1847 // Check for being unreachable, or for coming from a Rethrow. Rethrow's cannot | |
1848 // have the default "fall_through_index" path. | |
1849 const Type *CatchNode::Value( PhaseTransform *phase ) const { | |
1850 // Unreachable? Then so are all paths from here. | |
1851 if( phase->type(in(0)) == Type::TOP ) return Type::TOP; | |
1852 // First assume all paths are reachable | |
1853 const Type** f = TypeTuple::fields(_size); | |
1854 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; | |
1855 // Identify cases that will always throw an exception | |
1856 // () rethrow call | |
1857 // () virtual or interface call with NULL receiver | |
1858 // () call is a check cast with incompatible arguments | |
1859 if( in(1)->is_Proj() ) { | |
1860 Node *i10 = in(1)->in(0); | |
1861 if( i10->is_Call() ) { | |
1862 CallNode *call = i10->as_Call(); | |
1863 // Rethrows always throw exceptions, never return | |
1864 if (call->entry_point() == OptoRuntime::rethrow_stub()) { | |
1865 f[CatchProjNode::fall_through_index] = Type::TOP; | |
1866 } else if( call->req() > TypeFunc::Parms ) { | |
1867 const Type *arg0 = phase->type( call->in(TypeFunc::Parms) ); | |
1868 // Check for null reciever to virtual or interface calls | |
1869 if( call->is_CallDynamicJava() && | |
1870 arg0->higher_equal(TypePtr::NULL_PTR) ) { | |
1871 f[CatchProjNode::fall_through_index] = Type::TOP; | |
1872 } | |
1873 } // End of if not a runtime stub | |
1874 } // End of if have call above me | |
1875 } // End of slot 1 is not a projection | |
1876 return TypeTuple::make(_size, f); | |
1877 } | |
1878 | |
1879 //============================================================================= | |
1880 uint CatchProjNode::hash() const { | |
1881 return Node::hash() + _handler_bci; | |
1882 } | |
1883 | |
1884 | |
1885 uint CatchProjNode::cmp( const Node &n ) const { | |
1886 return ProjNode::cmp(n) && | |
1887 _handler_bci == ((CatchProjNode&)n)._handler_bci; | |
1888 } | |
1889 | |
1890 | |
1891 //------------------------------Identity--------------------------------------- | |
1892 // If only 1 target is possible, choose it if it is the main control | |
1893 Node *CatchProjNode::Identity( PhaseTransform *phase ) { | |
1894 // If my value is control and no other value is, then treat as ID | |
1895 const TypeTuple *t = phase->type(in(0))->is_tuple(); | |
1896 if (t->field_at(_con) != Type::CONTROL) return this; | |
1897 // If we remove the last CatchProj and elide the Catch/CatchProj, then we | |
1898 // also remove any exception table entry. Thus we must know the call | |
1899 // feeding the Catch will not really throw an exception. This is ok for | |
1900 // the main fall-thru control (happens when we know a call can never throw | |
1901 // an exception) or for "rethrow", because a further optimnization will | |
1902 // yank the rethrow (happens when we inline a function that can throw an | |
1903 // exception and the caller has no handler). Not legal, e.g., for passing | |
1904 // a NULL receiver to a v-call, or passing bad types to a slow-check-cast. | |
1905 // These cases MUST throw an exception via the runtime system, so the VM | |
1906 // will be looking for a table entry. | |
1907 Node *proj = in(0)->in(1); // Expect a proj feeding CatchNode | |
1908 CallNode *call; | |
1909 if (_con != TypeFunc::Control && // Bail out if not the main control. | |
1910 !(proj->is_Proj() && // AND NOT a rethrow | |
1911 proj->in(0)->is_Call() && | |
1912 (call = proj->in(0)->as_Call()) && | |
1913 call->entry_point() == OptoRuntime::rethrow_stub())) | |
1914 return this; | |
1915 | |
1916 // Search for any other path being control | |
1917 for (uint i = 0; i < t->cnt(); i++) { | |
1918 if (i != _con && t->field_at(i) == Type::CONTROL) | |
1919 return this; | |
1920 } | |
1921 // Only my path is possible; I am identity on control to the jump | |
1922 return in(0)->in(0); | |
1923 } | |
1924 | |
1925 | |
1926 #ifndef PRODUCT | |
1927 void CatchProjNode::dump_spec(outputStream *st) const { | |
1928 ProjNode::dump_spec(st); | |
1929 st->print("@bci %d ",_handler_bci); | |
1930 } | |
1931 #endif | |
1932 | |
1933 //============================================================================= | |
1934 //------------------------------Identity--------------------------------------- | |
1935 // Check for CreateEx being Identity. | |
1936 Node *CreateExNode::Identity( PhaseTransform *phase ) { | |
1937 if( phase->type(in(1)) == Type::TOP ) return in(1); | |
1938 if( phase->type(in(0)) == Type::TOP ) return in(0); | |
1939 // We only come from CatchProj, unless the CatchProj goes away. | |
1940 // If the CatchProj is optimized away, then we just carry the | |
1941 // exception oop through. | |
1942 CallNode *call = in(1)->in(0)->as_Call(); | |
1943 | |
1944 return ( in(0)->is_CatchProj() && in(0)->in(0)->in(1) == in(1) ) | |
1945 ? this | |
1946 : call->in(TypeFunc::Parms); | |
1947 } | |
1948 | |
1949 //============================================================================= | |
1950 #ifndef PRODUCT | |
1951 void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const { | |
1952 st->print("%s", Name()); | |
1953 } | |
1954 #endif |