Mercurial > hg > truffle
annotate src/share/vm/opto/cfgnode.cpp @ 74:2a9af0b9cb1c
6674600: (Escape Analysis) Optimize memory graph for instance's fields
Summary: EA gives opportunite to do more aggressive memory optimizations.
Reviewed-by: never, jrose
| author | kvn |
|---|---|
| date | Thu, 20 Mar 2008 15:11:44 -0700 |
| parents | a61af66fc99e |
| children | ba764ed4b6f2 |
| rev | line source |
|---|---|
| 0 | 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 | |
|
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707 //------------------------split_out_instance----------------------------------- |
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708 // Split out an instance type from a bottom phi. |
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709 PhiNode* PhiNode::split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const { |
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710 assert(type() == Type::MEMORY && (adr_type() == TypePtr::BOTTOM || |
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711 adr_type() == TypeRawPtr::BOTTOM) , "bottom or raw memory required"); |
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712 |
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713 // Check if an appropriate node already exists. |
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714 Node *region = in(0); |
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715 for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) { |
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716 Node* use = region->fast_out(k); |
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717 if( use->is_Phi()) { |
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718 PhiNode *phi2 = use->as_Phi(); |
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719 if (phi2->type() == Type::MEMORY && phi2->adr_type() == at) { |
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720 return phi2; |
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721 } |
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722 } |
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723 } |
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724 Compile *C = igvn->C; |
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725 Arena *a = Thread::current()->resource_area(); |
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726 Node_Array node_map = new Node_Array(a); |
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727 Node_Stack stack(a, C->unique() >> 4); |
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728 PhiNode *nphi = slice_memory(at); |
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729 igvn->register_new_node_with_optimizer( nphi ); |
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730 node_map.map(_idx, nphi); |
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731 stack.push((Node *)this, 1); |
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732 while(!stack.is_empty()) { |
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733 PhiNode *ophi = stack.node()->as_Phi(); |
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734 uint i = stack.index(); |
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735 assert(i >= 1, "not control edge"); |
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736 stack.pop(); |
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737 nphi = node_map[ophi->_idx]->as_Phi(); |
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738 for (; i < ophi->req(); i++) { |
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739 Node *in = ophi->in(i); |
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740 if (in == NULL || igvn->type(in) == Type::TOP) |
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741 continue; |
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742 Node *opt = MemNode::optimize_simple_memory_chain(in, at, igvn); |
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743 PhiNode *optphi = opt->is_Phi() ? opt->as_Phi() : NULL; |
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744 if (optphi != NULL && optphi->adr_type() == TypePtr::BOTTOM) { |
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745 opt = node_map[optphi->_idx]; |
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746 if (opt == NULL) { |
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747 stack.push(ophi, i); |
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748 nphi = optphi->slice_memory(at); |
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749 igvn->register_new_node_with_optimizer( nphi ); |
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750 node_map.map(optphi->_idx, nphi); |
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751 ophi = optphi; |
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752 i = 0; // will get incremented at top of loop |
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753 continue; |
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754 } |
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755 } |
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756 nphi->set_req(i, opt); |
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757 } |
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758 } |
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759 return nphi; |
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760 } |
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761 |
| 0 | 762 //------------------------verify_adr_type-------------------------------------- |
| 763 #ifdef ASSERT | |
| 764 void PhiNode::verify_adr_type(VectorSet& visited, const TypePtr* at) const { | |
| 765 if (visited.test_set(_idx)) return; //already visited | |
| 766 | |
| 767 // recheck constructor invariants: | |
| 768 verify_adr_type(false); | |
| 769 | |
| 770 // recheck local phi/phi consistency: | |
| 771 assert(_adr_type == at || _adr_type == TypePtr::BOTTOM, | |
| 772 "adr_type must be consistent across phi nest"); | |
| 773 | |
| 774 // walk around | |
| 775 for (uint i = 1; i < req(); i++) { | |
| 776 Node* n = in(i); | |
| 777 if (n == NULL) continue; | |
| 778 const Node* np = in(i); | |
| 779 if (np->is_Phi()) { | |
| 780 np->as_Phi()->verify_adr_type(visited, at); | |
| 781 } else if (n->bottom_type() == Type::TOP | |
| 782 || (n->is_Mem() && n->in(MemNode::Address)->bottom_type() == Type::TOP)) { | |
| 783 // ignore top inputs | |
| 784 } else { | |
| 785 const TypePtr* nat = flatten_phi_adr_type(n->adr_type()); | |
| 786 // recheck phi/non-phi consistency at leaves: | |
| 787 assert((nat != NULL) == (at != NULL), ""); | |
| 788 assert(nat == at || nat == TypePtr::BOTTOM, | |
| 789 "adr_type must be consistent at leaves of phi nest"); | |
| 790 } | |
| 791 } | |
| 792 } | |
| 793 | |
| 794 // Verify a whole nest of phis rooted at this one. | |
| 795 void PhiNode::verify_adr_type(bool recursive) const { | |
| 796 if (is_error_reported()) return; // muzzle asserts when debugging an error | |
| 797 if (Node::in_dump()) return; // muzzle asserts when printing | |
| 798 | |
| 799 assert((_type == Type::MEMORY) == (_adr_type != NULL), "adr_type for memory phis only"); | |
| 800 | |
| 801 if (!VerifyAliases) return; // verify thoroughly only if requested | |
| 802 | |
| 803 assert(_adr_type == flatten_phi_adr_type(_adr_type), | |
| 804 "Phi::adr_type must be pre-normalized"); | |
| 805 | |
| 806 if (recursive) { | |
| 807 VectorSet visited(Thread::current()->resource_area()); | |
| 808 verify_adr_type(visited, _adr_type); | |
| 809 } | |
| 810 } | |
| 811 #endif | |
| 812 | |
| 813 | |
| 814 //------------------------------Value------------------------------------------ | |
| 815 // Compute the type of the PhiNode | |
| 816 const Type *PhiNode::Value( PhaseTransform *phase ) const { | |
| 817 Node *r = in(0); // RegionNode | |
| 818 if( !r ) // Copy or dead | |
| 819 return in(1) ? phase->type(in(1)) : Type::TOP; | |
| 820 | |
| 821 // Note: During parsing, phis are often transformed before their regions. | |
| 822 // This means we have to use type_or_null to defend against untyped regions. | |
| 823 if( phase->type_or_null(r) == Type::TOP ) // Dead code? | |
| 824 return Type::TOP; | |
| 825 | |
| 826 // Check for trip-counted loop. If so, be smarter. | |
| 827 CountedLoopNode *l = r->is_CountedLoop() ? r->as_CountedLoop() : NULL; | |
| 828 if( l && l->can_be_counted_loop(phase) && | |
| 829 ((const Node*)l->phi() == this) ) { // Trip counted loop! | |
| 830 // protect against init_trip() or limit() returning NULL | |
| 831 const Node *init = l->init_trip(); | |
| 832 const Node *limit = l->limit(); | |
| 833 if( init != NULL && limit != NULL && l->stride_is_con() ) { | |
| 834 const TypeInt *lo = init ->bottom_type()->isa_int(); | |
| 835 const TypeInt *hi = limit->bottom_type()->isa_int(); | |
| 836 if( lo && hi ) { // Dying loops might have TOP here | |
| 837 int stride = l->stride_con(); | |
| 838 if( stride < 0 ) { // Down-counter loop | |
| 839 const TypeInt *tmp = lo; lo = hi; hi = tmp; | |
| 840 stride = -stride; | |
| 841 } | |
| 842 if( lo->_hi < hi->_lo ) // Reversed endpoints are well defined :-( | |
| 843 return TypeInt::make(lo->_lo,hi->_hi,3); | |
| 844 } | |
| 845 } | |
| 846 } | |
| 847 | |
| 848 // Until we have harmony between classes and interfaces in the type | |
| 849 // lattice, we must tread carefully around phis which implicitly | |
| 850 // convert the one to the other. | |
| 851 const TypeInstPtr* ttip = _type->isa_instptr(); | |
| 852 bool is_intf = false; | |
| 853 if (ttip != NULL) { | |
| 854 ciKlass* k = ttip->klass(); | |
| 855 if (k->is_loaded() && k->is_interface()) | |
| 856 is_intf = true; | |
| 857 } | |
| 858 | |
| 859 // Default case: merge all inputs | |
| 860 const Type *t = Type::TOP; // Merged type starting value | |
| 861 for (uint i = 1; i < req(); ++i) {// For all paths in | |
| 862 // Reachable control path? | |
| 863 if (r->in(i) && phase->type(r->in(i)) == Type::CONTROL) { | |
| 864 const Type* ti = phase->type(in(i)); | |
| 865 // We assume that each input of an interface-valued Phi is a true | |
| 866 // subtype of that interface. This might not be true of the meet | |
| 867 // of all the input types. The lattice is not distributive in | |
| 868 // such cases. Ward off asserts in type.cpp by refusing to do | |
| 869 // meets between interfaces and proper classes. | |
| 870 const TypeInstPtr* tiip = ti->isa_instptr(); | |
| 871 if (tiip) { | |
| 872 bool ti_is_intf = false; | |
| 873 ciKlass* k = tiip->klass(); | |
| 874 if (k->is_loaded() && k->is_interface()) | |
| 875 ti_is_intf = true; | |
| 876 if (is_intf != ti_is_intf) | |
| 877 { t = _type; break; } | |
| 878 } | |
| 879 t = t->meet(ti); | |
| 880 } | |
| 881 } | |
| 882 | |
| 883 // The worst-case type (from ciTypeFlow) should be consistent with "t". | |
| 884 // That is, we expect that "t->higher_equal(_type)" holds true. | |
| 885 // There are various exceptions: | |
| 886 // - Inputs which are phis might in fact be widened unnecessarily. | |
| 887 // For example, an input might be a widened int while the phi is a short. | |
| 888 // - Inputs might be BotPtrs but this phi is dependent on a null check, | |
| 889 // and postCCP has removed the cast which encodes the result of the check. | |
| 890 // - The type of this phi is an interface, and the inputs are classes. | |
| 891 // - Value calls on inputs might produce fuzzy results. | |
| 892 // (Occurrences of this case suggest improvements to Value methods.) | |
| 893 // | |
| 894 // It is not possible to see Type::BOTTOM values as phi inputs, | |
| 895 // because the ciTypeFlow pre-pass produces verifier-quality types. | |
| 896 const Type* ft = t->filter(_type); // Worst case type | |
| 897 | |
| 898 #ifdef ASSERT | |
| 899 // The following logic has been moved into TypeOopPtr::filter. | |
| 900 const Type* jt = t->join(_type); | |
| 901 if( jt->empty() ) { // Emptied out??? | |
| 902 | |
| 903 // Check for evil case of 't' being a class and '_type' expecting an | |
| 904 // interface. This can happen because the bytecodes do not contain | |
| 905 // enough type info to distinguish a Java-level interface variable | |
| 906 // from a Java-level object variable. If we meet 2 classes which | |
| 907 // both implement interface I, but their meet is at 'j/l/O' which | |
| 908 // doesn't implement I, we have no way to tell if the result should | |
| 909 // be 'I' or 'j/l/O'. Thus we'll pick 'j/l/O'. If this then flows | |
| 910 // into a Phi which "knows" it's an Interface type we'll have to | |
| 911 // uplift the type. | |
| 912 if( !t->empty() && ttip && ttip->is_loaded() && ttip->klass()->is_interface() ) | |
| 913 { assert(ft == _type, ""); } // Uplift to interface | |
| 914 // Otherwise it's something stupid like non-overlapping int ranges | |
| 915 // found on dying counted loops. | |
| 916 else | |
| 917 { assert(ft == Type::TOP, ""); } // Canonical empty value | |
| 918 } | |
| 919 | |
| 920 else { | |
| 921 | |
| 922 // If we have an interface-typed Phi and we narrow to a class type, the join | |
| 923 // should report back the class. However, if we have a J/L/Object | |
| 924 // class-typed Phi and an interface flows in, it's possible that the meet & | |
| 925 // join report an interface back out. This isn't possible but happens | |
| 926 // because the type system doesn't interact well with interfaces. | |
| 927 const TypeInstPtr *jtip = jt->isa_instptr(); | |
| 928 if( jtip && ttip ) { | |
| 929 if( jtip->is_loaded() && jtip->klass()->is_interface() && | |
| 930 ttip->is_loaded() && !ttip->klass()->is_interface() ) | |
| 931 // Happens in a CTW of rt.jar, 320-341, no extra flags | |
| 932 { assert(ft == ttip->cast_to_ptr_type(jtip->ptr()), ""); jt = ft; } | |
| 933 } | |
| 934 if (jt != ft && jt->base() == ft->base()) { | |
| 935 if (jt->isa_int() && | |
| 936 jt->is_int()->_lo == ft->is_int()->_lo && | |
| 937 jt->is_int()->_hi == ft->is_int()->_hi) | |
| 938 jt = ft; | |
| 939 if (jt->isa_long() && | |
| 940 jt->is_long()->_lo == ft->is_long()->_lo && | |
| 941 jt->is_long()->_hi == ft->is_long()->_hi) | |
| 942 jt = ft; | |
| 943 } | |
| 944 if (jt != ft) { | |
| 945 tty->print("merge type: "); t->dump(); tty->cr(); | |
| 946 tty->print("kill type: "); _type->dump(); tty->cr(); | |
| 947 tty->print("join type: "); jt->dump(); tty->cr(); | |
| 948 tty->print("filter type: "); ft->dump(); tty->cr(); | |
| 949 } | |
| 950 assert(jt == ft, ""); | |
| 951 } | |
| 952 #endif //ASSERT | |
| 953 | |
| 954 // Deal with conversion problems found in data loops. | |
| 955 ft = phase->saturate(ft, phase->type_or_null(this), _type); | |
| 956 | |
| 957 return ft; | |
| 958 } | |
| 959 | |
| 960 | |
| 961 //------------------------------is_diamond_phi--------------------------------- | |
| 962 // Does this Phi represent a simple well-shaped diamond merge? Return the | |
| 963 // index of the true path or 0 otherwise. | |
| 964 int PhiNode::is_diamond_phi() const { | |
| 965 // Check for a 2-path merge | |
| 966 Node *region = in(0); | |
| 967 if( !region ) return 0; | |
| 968 if( region->req() != 3 ) return 0; | |
| 969 if( req() != 3 ) return 0; | |
| 970 // Check that both paths come from the same If | |
| 971 Node *ifp1 = region->in(1); | |
| 972 Node *ifp2 = region->in(2); | |
| 973 if( !ifp1 || !ifp2 ) return 0; | |
| 974 Node *iff = ifp1->in(0); | |
| 975 if( !iff || !iff->is_If() ) return 0; | |
| 976 if( iff != ifp2->in(0) ) return 0; | |
| 977 // Check for a proper bool/cmp | |
| 978 const Node *b = iff->in(1); | |
| 979 if( !b->is_Bool() ) return 0; | |
| 980 const Node *cmp = b->in(1); | |
| 981 if( !cmp->is_Cmp() ) return 0; | |
| 982 | |
| 983 // Check for branching opposite expected | |
| 984 if( ifp2->Opcode() == Op_IfTrue ) { | |
| 985 assert( ifp1->Opcode() == Op_IfFalse, "" ); | |
| 986 return 2; | |
| 987 } else { | |
| 988 assert( ifp1->Opcode() == Op_IfTrue, "" ); | |
| 989 return 1; | |
| 990 } | |
| 991 } | |
| 992 | |
| 993 //----------------------------check_cmove_id----------------------------------- | |
| 994 // Check for CMove'ing a constant after comparing against the constant. | |
| 995 // Happens all the time now, since if we compare equality vs a constant in | |
| 996 // the parser, we "know" the variable is constant on one path and we force | |
| 997 // it. Thus code like "if( x==0 ) {/*EMPTY*/}" ends up inserting a | |
| 998 // conditional move: "x = (x==0)?0:x;". Yucko. This fix is slightly more | |
| 999 // general in that we don't need constants. Since CMove's are only inserted | |
| 1000 // in very special circumstances, we do it here on generic Phi's. | |
| 1001 Node* PhiNode::is_cmove_id(PhaseTransform* phase, int true_path) { | |
| 1002 assert(true_path !=0, "only diamond shape graph expected"); | |
| 1003 | |
| 1004 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: | |
| 1005 // phi->region->if_proj->ifnode->bool->cmp | |
| 1006 Node* region = in(0); | |
| 1007 Node* iff = region->in(1)->in(0); | |
| 1008 BoolNode* b = iff->in(1)->as_Bool(); | |
| 1009 Node* cmp = b->in(1); | |
| 1010 Node* tval = in(true_path); | |
| 1011 Node* fval = in(3-true_path); | |
| 1012 Node* id = CMoveNode::is_cmove_id(phase, cmp, tval, fval, b); | |
| 1013 if (id == NULL) | |
| 1014 return NULL; | |
| 1015 | |
| 1016 // Either value might be a cast that depends on a branch of 'iff'. | |
| 1017 // Since the 'id' value will float free of the diamond, either | |
| 1018 // decast or return failure. | |
| 1019 Node* ctl = id->in(0); | |
| 1020 if (ctl != NULL && ctl->in(0) == iff) { | |
| 1021 if (id->is_ConstraintCast()) { | |
| 1022 return id->in(1); | |
| 1023 } else { | |
| 1024 // Don't know how to disentangle this value. | |
| 1025 return NULL; | |
| 1026 } | |
| 1027 } | |
| 1028 | |
| 1029 return id; | |
| 1030 } | |
| 1031 | |
| 1032 //------------------------------Identity--------------------------------------- | |
| 1033 // Check for Region being Identity. | |
| 1034 Node *PhiNode::Identity( PhaseTransform *phase ) { | |
| 1035 // Check for no merging going on | |
| 1036 // (There used to be special-case code here when this->region->is_Loop. | |
| 1037 // It would check for a tributary phi on the backedge that the main phi | |
| 1038 // trivially, perhaps with a single cast. The unique_input method | |
| 1039 // does all this and more, by reducing such tributaries to 'this'.) | |
| 1040 Node* uin = unique_input(phase); | |
| 1041 if (uin != NULL) { | |
| 1042 return uin; | |
| 1043 } | |
| 1044 | |
| 1045 int true_path = is_diamond_phi(); | |
| 1046 if (true_path != 0) { | |
| 1047 Node* id = is_cmove_id(phase, true_path); | |
| 1048 if (id != NULL) return id; | |
| 1049 } | |
| 1050 | |
| 1051 return this; // No identity | |
| 1052 } | |
| 1053 | |
| 1054 //-----------------------------unique_input------------------------------------ | |
| 1055 // Find the unique value, discounting top, self-loops, and casts. | |
| 1056 // Return top if there are no inputs, and self if there are multiple. | |
| 1057 Node* PhiNode::unique_input(PhaseTransform* phase) { | |
| 1058 // 1) One unique direct input, or | |
| 1059 // 2) some of the inputs have an intervening ConstraintCast and | |
| 1060 // the type of input is the same or sharper (more specific) | |
| 1061 // than the phi's type. | |
| 1062 // 3) an input is a self loop | |
| 1063 // | |
| 1064 // 1) input or 2) input or 3) input __ | |
| 1065 // / \ / \ \ / \ | |
| 1066 // \ / | cast phi cast | |
| 1067 // phi \ / / \ / | |
| 1068 // phi / -- | |
| 1069 | |
| 1070 Node* r = in(0); // RegionNode | |
| 1071 if (r == NULL) return in(1); // Already degraded to a Copy | |
| 1072 Node* uncasted_input = NULL; // The unique uncasted input (ConstraintCasts removed) | |
| 1073 Node* direct_input = NULL; // The unique direct input | |
| 1074 | |
| 1075 for (uint i = 1, cnt = req(); i < cnt; ++i) { | |
| 1076 Node* rc = r->in(i); | |
| 1077 if (rc == NULL || phase->type(rc) == Type::TOP) | |
| 1078 continue; // ignore unreachable control path | |
| 1079 Node* n = in(i); | |
| 1080 Node* un = n->uncast(); | |
| 1081 if (un == NULL || un == this || phase->type(un) == Type::TOP) { | |
| 1082 continue; // ignore if top, or in(i) and "this" are in a data cycle | |
| 1083 } | |
| 1084 // Check for a unique uncasted input | |
| 1085 if (uncasted_input == NULL) { | |
| 1086 uncasted_input = un; | |
| 1087 } else if (uncasted_input != un) { | |
| 1088 uncasted_input = NodeSentinel; // no unique uncasted input | |
| 1089 } | |
| 1090 // Check for a unique direct input | |
| 1091 if (direct_input == NULL) { | |
| 1092 direct_input = n; | |
| 1093 } else if (direct_input != n) { | |
| 1094 direct_input = NodeSentinel; // no unique direct input | |
| 1095 } | |
| 1096 } | |
| 1097 if (direct_input == NULL) { | |
| 1098 return phase->C->top(); // no inputs | |
| 1099 } | |
| 1100 assert(uncasted_input != NULL,""); | |
| 1101 | |
| 1102 if (direct_input != NodeSentinel) { | |
| 1103 return direct_input; // one unique direct input | |
| 1104 } | |
| 1105 if (uncasted_input != NodeSentinel && | |
| 1106 phase->type(uncasted_input)->higher_equal(type())) { | |
| 1107 return uncasted_input; // one unique uncasted input | |
| 1108 } | |
| 1109 | |
| 1110 // Nothing. | |
| 1111 return NULL; | |
| 1112 } | |
| 1113 | |
| 1114 //------------------------------is_x2logic------------------------------------- | |
| 1115 // Check for simple convert-to-boolean pattern | |
| 1116 // If:(C Bool) Region:(IfF IfT) Phi:(Region 0 1) | |
| 1117 // Convert Phi to an ConvIB. | |
| 1118 static Node *is_x2logic( PhaseGVN *phase, PhiNode *phi, int true_path ) { | |
| 1119 assert(true_path !=0, "only diamond shape graph expected"); | |
| 1120 // Convert the true/false index into an expected 0/1 return. | |
| 1121 // Map 2->0 and 1->1. | |
| 1122 int flipped = 2-true_path; | |
| 1123 | |
| 1124 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: | |
| 1125 // phi->region->if_proj->ifnode->bool->cmp | |
| 1126 Node *region = phi->in(0); | |
| 1127 Node *iff = region->in(1)->in(0); | |
| 1128 BoolNode *b = (BoolNode*)iff->in(1); | |
| 1129 const CmpNode *cmp = (CmpNode*)b->in(1); | |
| 1130 | |
| 1131 Node *zero = phi->in(1); | |
| 1132 Node *one = phi->in(2); | |
| 1133 const Type *tzero = phase->type( zero ); | |
| 1134 const Type *tone = phase->type( one ); | |
| 1135 | |
| 1136 // Check for compare vs 0 | |
| 1137 const Type *tcmp = phase->type(cmp->in(2)); | |
| 1138 if( tcmp != TypeInt::ZERO && tcmp != TypePtr::NULL_PTR ) { | |
| 1139 // Allow cmp-vs-1 if the other input is bounded by 0-1 | |
| 1140 if( !(tcmp == TypeInt::ONE && phase->type(cmp->in(1)) == TypeInt::BOOL) ) | |
| 1141 return NULL; | |
| 1142 flipped = 1-flipped; // Test is vs 1 instead of 0! | |
| 1143 } | |
| 1144 | |
| 1145 // Check for setting zero/one opposite expected | |
| 1146 if( tzero == TypeInt::ZERO ) { | |
| 1147 if( tone == TypeInt::ONE ) { | |
| 1148 } else return NULL; | |
| 1149 } else if( tzero == TypeInt::ONE ) { | |
| 1150 if( tone == TypeInt::ZERO ) { | |
| 1151 flipped = 1-flipped; | |
| 1152 } else return NULL; | |
| 1153 } else return NULL; | |
| 1154 | |
| 1155 // Check for boolean test backwards | |
| 1156 if( b->_test._test == BoolTest::ne ) { | |
| 1157 } else if( b->_test._test == BoolTest::eq ) { | |
| 1158 flipped = 1-flipped; | |
| 1159 } else return NULL; | |
| 1160 | |
| 1161 // Build int->bool conversion | |
| 1162 Node *n = new (phase->C, 2) Conv2BNode( cmp->in(1) ); | |
| 1163 if( flipped ) | |
| 1164 n = new (phase->C, 3) XorINode( phase->transform(n), phase->intcon(1) ); | |
| 1165 | |
| 1166 return n; | |
| 1167 } | |
| 1168 | |
| 1169 //------------------------------is_cond_add------------------------------------ | |
| 1170 // Check for simple conditional add pattern: "(P < Q) ? X+Y : X;" | |
| 1171 // To be profitable the control flow has to disappear; there can be no other | |
| 1172 // values merging here. We replace the test-and-branch with: | |
| 1173 // "(sgn(P-Q))&Y) + X". Basically, convert "(P < Q)" into 0 or -1 by | |
| 1174 // moving the carry bit from (P-Q) into a register with 'sbb EAX,EAX'. | |
| 1175 // Then convert Y to 0-or-Y and finally add. | |
| 1176 // This is a key transform for SpecJava _201_compress. | |
| 1177 static Node* is_cond_add(PhaseGVN *phase, PhiNode *phi, int true_path) { | |
| 1178 assert(true_path !=0, "only diamond shape graph expected"); | |
| 1179 | |
| 1180 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: | |
| 1181 // phi->region->if_proj->ifnode->bool->cmp | |
| 1182 RegionNode *region = (RegionNode*)phi->in(0); | |
| 1183 Node *iff = region->in(1)->in(0); | |
| 1184 BoolNode* b = iff->in(1)->as_Bool(); | |
| 1185 const CmpNode *cmp = (CmpNode*)b->in(1); | |
| 1186 | |
| 1187 // Make sure only merging this one phi here | |
| 1188 if (region->has_unique_phi() != phi) return NULL; | |
| 1189 | |
| 1190 // Make sure each arm of the diamond has exactly one output, which we assume | |
| 1191 // is the region. Otherwise, the control flow won't disappear. | |
| 1192 if (region->in(1)->outcnt() != 1) return NULL; | |
| 1193 if (region->in(2)->outcnt() != 1) return NULL; | |
| 1194 | |
| 1195 // Check for "(P < Q)" of type signed int | |
| 1196 if (b->_test._test != BoolTest::lt) return NULL; | |
| 1197 if (cmp->Opcode() != Op_CmpI) return NULL; | |
| 1198 | |
| 1199 Node *p = cmp->in(1); | |
| 1200 Node *q = cmp->in(2); | |
| 1201 Node *n1 = phi->in( true_path); | |
| 1202 Node *n2 = phi->in(3-true_path); | |
| 1203 | |
| 1204 int op = n1->Opcode(); | |
| 1205 if( op != Op_AddI // Need zero as additive identity | |
| 1206 /*&&op != Op_SubI && | |
| 1207 op != Op_AddP && | |
| 1208 op != Op_XorI && | |
| 1209 op != Op_OrI*/ ) | |
| 1210 return NULL; | |
| 1211 | |
| 1212 Node *x = n2; | |
| 1213 Node *y = n1->in(1); | |
| 1214 if( n2 == n1->in(1) ) { | |
| 1215 y = n1->in(2); | |
| 1216 } else if( n2 == n1->in(1) ) { | |
| 1217 } else return NULL; | |
| 1218 | |
| 1219 // Not so profitable if compare and add are constants | |
| 1220 if( q->is_Con() && phase->type(q) != TypeInt::ZERO && y->is_Con() ) | |
| 1221 return NULL; | |
| 1222 | |
| 1223 Node *cmplt = phase->transform( new (phase->C, 3) CmpLTMaskNode(p,q) ); | |
| 1224 Node *j_and = phase->transform( new (phase->C, 3) AndINode(cmplt,y) ); | |
| 1225 return new (phase->C, 3) AddINode(j_and,x); | |
| 1226 } | |
| 1227 | |
| 1228 //------------------------------is_absolute------------------------------------ | |
| 1229 // Check for absolute value. | |
| 1230 static Node* is_absolute( PhaseGVN *phase, PhiNode *phi_root, int true_path) { | |
| 1231 assert(true_path !=0, "only diamond shape graph expected"); | |
| 1232 | |
| 1233 int cmp_zero_idx = 0; // Index of compare input where to look for zero | |
| 1234 int phi_x_idx = 0; // Index of phi input where to find naked x | |
| 1235 | |
| 1236 // ABS ends with the merge of 2 control flow paths. | |
| 1237 // Find the false path from the true path. With only 2 inputs, 3 - x works nicely. | |
| 1238 int false_path = 3 - true_path; | |
| 1239 | |
| 1240 // is_diamond_phi() has guaranteed the correctness of the nodes sequence: | |
| 1241 // phi->region->if_proj->ifnode->bool->cmp | |
| 1242 BoolNode *bol = phi_root->in(0)->in(1)->in(0)->in(1)->as_Bool(); | |
| 1243 | |
| 1244 // Check bool sense | |
| 1245 switch( bol->_test._test ) { | |
| 1246 case BoolTest::lt: cmp_zero_idx = 1; phi_x_idx = true_path; break; | |
| 1247 case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break; | |
| 1248 case BoolTest::gt: cmp_zero_idx = 2; phi_x_idx = true_path; break; | |
| 1249 case BoolTest::ge: cmp_zero_idx = 1; phi_x_idx = false_path; break; | |
| 1250 default: return NULL; break; | |
| 1251 } | |
| 1252 | |
| 1253 // Test is next | |
| 1254 Node *cmp = bol->in(1); | |
| 1255 const Type *tzero = NULL; | |
| 1256 switch( cmp->Opcode() ) { | |
| 1257 case Op_CmpF: tzero = TypeF::ZERO; break; // Float ABS | |
| 1258 case Op_CmpD: tzero = TypeD::ZERO; break; // Double ABS | |
| 1259 default: return NULL; | |
| 1260 } | |
| 1261 | |
| 1262 // Find zero input of compare; the other input is being abs'd | |
| 1263 Node *x = NULL; | |
| 1264 bool flip = false; | |
| 1265 if( phase->type(cmp->in(cmp_zero_idx)) == tzero ) { | |
| 1266 x = cmp->in(3 - cmp_zero_idx); | |
| 1267 } else if( phase->type(cmp->in(3 - cmp_zero_idx)) == tzero ) { | |
| 1268 // The test is inverted, we should invert the result... | |
| 1269 x = cmp->in(cmp_zero_idx); | |
| 1270 flip = true; | |
| 1271 } else { | |
| 1272 return NULL; | |
| 1273 } | |
| 1274 | |
| 1275 // Next get the 2 pieces being selected, one is the original value | |
| 1276 // and the other is the negated value. | |
| 1277 if( phi_root->in(phi_x_idx) != x ) return NULL; | |
| 1278 | |
| 1279 // Check other phi input for subtract node | |
| 1280 Node *sub = phi_root->in(3 - phi_x_idx); | |
| 1281 | |
| 1282 // Allow only Sub(0,X) and fail out for all others; Neg is not OK | |
| 1283 if( tzero == TypeF::ZERO ) { | |
| 1284 if( sub->Opcode() != Op_SubF || | |
| 1285 sub->in(2) != x || | |
| 1286 phase->type(sub->in(1)) != tzero ) return NULL; | |
| 1287 x = new (phase->C, 2) AbsFNode(x); | |
| 1288 if (flip) { | |
| 1289 x = new (phase->C, 3) SubFNode(sub->in(1), phase->transform(x)); | |
| 1290 } | |
| 1291 } else { | |
| 1292 if( sub->Opcode() != Op_SubD || | |
| 1293 sub->in(2) != x || | |
| 1294 phase->type(sub->in(1)) != tzero ) return NULL; | |
| 1295 x = new (phase->C, 2) AbsDNode(x); | |
| 1296 if (flip) { | |
| 1297 x = new (phase->C, 3) SubDNode(sub->in(1), phase->transform(x)); | |
| 1298 } | |
| 1299 } | |
| 1300 | |
| 1301 return x; | |
| 1302 } | |
| 1303 | |
| 1304 //------------------------------split_once------------------------------------- | |
| 1305 // Helper for split_flow_path | |
| 1306 static void split_once(PhaseIterGVN *igvn, Node *phi, Node *val, Node *n, Node *newn) { | |
| 1307 igvn->hash_delete(n); // Remove from hash before hacking edges | |
| 1308 | |
| 1309 uint j = 1; | |
| 1310 for( uint i = phi->req()-1; i > 0; i-- ) { | |
| 1311 if( phi->in(i) == val ) { // Found a path with val? | |
| 1312 // Add to NEW Region/Phi, no DU info | |
| 1313 newn->set_req( j++, n->in(i) ); | |
| 1314 // Remove from OLD Region/Phi | |
| 1315 n->del_req(i); | |
| 1316 } | |
| 1317 } | |
| 1318 | |
| 1319 // Register the new node but do not transform it. Cannot transform until the | |
| 1320 // entire Region/Phi conglerate has been hacked as a single huge transform. | |
| 1321 igvn->register_new_node_with_optimizer( newn ); | |
| 1322 // Now I can point to the new node. | |
| 1323 n->add_req(newn); | |
| 1324 igvn->_worklist.push(n); | |
| 1325 } | |
| 1326 | |
| 1327 //------------------------------split_flow_path-------------------------------- | |
| 1328 // Check for merging identical values and split flow paths | |
| 1329 static Node* split_flow_path(PhaseGVN *phase, PhiNode *phi) { | |
| 1330 BasicType bt = phi->type()->basic_type(); | |
| 1331 if( bt == T_ILLEGAL || type2size[bt] <= 0 ) | |
| 1332 return NULL; // Bail out on funny non-value stuff | |
| 1333 if( phi->req() <= 3 ) // Need at least 2 matched inputs and a | |
| 1334 return NULL; // third unequal input to be worth doing | |
| 1335 | |
| 1336 // Scan for a constant | |
| 1337 uint i; | |
| 1338 for( i = 1; i < phi->req()-1; i++ ) { | |
| 1339 Node *n = phi->in(i); | |
| 1340 if( !n ) return NULL; | |
| 1341 if( phase->type(n) == Type::TOP ) return NULL; | |
| 1342 if( n->Opcode() == Op_ConP ) | |
| 1343 break; | |
| 1344 } | |
| 1345 if( i >= phi->req() ) // Only split for constants | |
| 1346 return NULL; | |
| 1347 | |
| 1348 Node *val = phi->in(i); // Constant to split for | |
| 1349 uint hit = 0; // Number of times it occurs | |
| 1350 | |
| 1351 for( ; i < phi->req(); i++ ){ // Count occurances of constant | |
| 1352 Node *n = phi->in(i); | |
| 1353 if( !n ) return NULL; | |
| 1354 if( phase->type(n) == Type::TOP ) return NULL; | |
| 1355 if( phi->in(i) == val ) | |
| 1356 hit++; | |
| 1357 } | |
| 1358 | |
| 1359 if( hit <= 1 || // Make sure we find 2 or more | |
| 1360 hit == phi->req()-1 ) // and not ALL the same value | |
| 1361 return NULL; | |
| 1362 | |
| 1363 // Now start splitting out the flow paths that merge the same value. | |
| 1364 // Split first the RegionNode. | |
| 1365 PhaseIterGVN *igvn = phase->is_IterGVN(); | |
| 1366 Node *r = phi->region(); | |
| 1367 RegionNode *newr = new (phase->C, hit+1) RegionNode(hit+1); | |
| 1368 split_once(igvn, phi, val, r, newr); | |
| 1369 | |
| 1370 // Now split all other Phis than this one | |
| 1371 for (DUIterator_Fast kmax, k = r->fast_outs(kmax); k < kmax; k++) { | |
| 1372 Node* phi2 = r->fast_out(k); | |
| 1373 if( phi2->is_Phi() && phi2->as_Phi() != phi ) { | |
| 1374 PhiNode *newphi = PhiNode::make_blank(newr, phi2); | |
| 1375 split_once(igvn, phi, val, phi2, newphi); | |
| 1376 } | |
| 1377 } | |
| 1378 | |
| 1379 // Clean up this guy | |
| 1380 igvn->hash_delete(phi); | |
| 1381 for( i = phi->req()-1; i > 0; i-- ) { | |
| 1382 if( phi->in(i) == val ) { | |
| 1383 phi->del_req(i); | |
| 1384 } | |
| 1385 } | |
| 1386 phi->add_req(val); | |
| 1387 | |
| 1388 return phi; | |
| 1389 } | |
| 1390 | |
| 1391 //============================================================================= | |
| 1392 //------------------------------simple_data_loop_check------------------------- | |
| 1393 // Try to determing if the phi node in a simple safe/unsafe data loop. | |
| 1394 // Returns: | |
| 1395 // enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop }; | |
| 1396 // Safe - safe case when the phi and it's inputs reference only safe data | |
| 1397 // nodes; | |
| 1398 // Unsafe - the phi and it's inputs reference unsafe data nodes but there | |
| 1399 // is no reference back to the phi - need a graph walk | |
| 1400 // to determine if it is in a loop; | |
| 1401 // UnsafeLoop - unsafe case when the phi references itself directly or through | |
| 1402 // unsafe data node. | |
| 1403 // Note: a safe data node is a node which could/never reference itself during | |
| 1404 // GVN transformations. For now it is Con, Proj, Phi, CastPP, CheckCastPP. | |
| 1405 // I mark Phi nodes as safe node not only because they can reference itself | |
| 1406 // but also to prevent mistaking the fallthrough case inside an outer loop | |
| 1407 // as dead loop when the phi references itselfs through an other phi. | |
| 1408 PhiNode::LoopSafety PhiNode::simple_data_loop_check(Node *in) const { | |
| 1409 // It is unsafe loop if the phi node references itself directly. | |
| 1410 if (in == (Node*)this) | |
| 1411 return UnsafeLoop; // Unsafe loop | |
| 1412 // Unsafe loop if the phi node references itself through an unsafe data node. | |
| 1413 // Exclude cases with null inputs or data nodes which could reference | |
| 1414 // itself (safe for dead loops). | |
| 1415 if (in != NULL && !in->is_dead_loop_safe()) { | |
| 1416 // Check inputs of phi's inputs also. | |
| 1417 // It is much less expensive then full graph walk. | |
| 1418 uint cnt = in->req(); | |
| 1419 for (uint i = 1; i < cnt; ++i) { | |
| 1420 Node* m = in->in(i); | |
| 1421 if (m == (Node*)this) | |
| 1422 return UnsafeLoop; // Unsafe loop | |
| 1423 if (m != NULL && !m->is_dead_loop_safe()) { | |
| 1424 // Check the most common case (about 30% of all cases): | |
| 1425 // phi->Load/Store->AddP->(ConP ConP Con)/(Parm Parm Con). | |
| 1426 Node *m1 = (m->is_AddP() && m->req() > 3) ? m->in(1) : NULL; | |
| 1427 if (m1 == (Node*)this) | |
| 1428 return UnsafeLoop; // Unsafe loop | |
| 1429 if (m1 != NULL && m1 == m->in(2) && | |
| 1430 m1->is_dead_loop_safe() && m->in(3)->is_Con()) { | |
| 1431 continue; // Safe case | |
| 1432 } | |
| 1433 // The phi references an unsafe node - need full analysis. | |
| 1434 return Unsafe; | |
| 1435 } | |
| 1436 } | |
| 1437 } | |
| 1438 return Safe; // Safe case - we can optimize the phi node. | |
| 1439 } | |
| 1440 | |
| 1441 //------------------------------is_unsafe_data_reference----------------------- | |
| 1442 // If phi can be reached through the data input - it is data loop. | |
| 1443 bool PhiNode::is_unsafe_data_reference(Node *in) const { | |
| 1444 assert(req() > 1, ""); | |
| 1445 // First, check simple cases when phi references itself directly or | |
| 1446 // through an other node. | |
| 1447 LoopSafety safety = simple_data_loop_check(in); | |
| 1448 if (safety == UnsafeLoop) | |
| 1449 return true; // phi references itself - unsafe loop | |
| 1450 else if (safety == Safe) | |
| 1451 return false; // Safe case - phi could be replaced with the unique input. | |
| 1452 | |
| 1453 // Unsafe case when we should go through data graph to determine | |
| 1454 // if the phi references itself. | |
| 1455 | |
| 1456 ResourceMark rm; | |
| 1457 | |
| 1458 Arena *a = Thread::current()->resource_area(); | |
| 1459 Node_List nstack(a); | |
| 1460 VectorSet visited(a); | |
| 1461 | |
| 1462 nstack.push(in); // Start with unique input. | |
| 1463 visited.set(in->_idx); | |
| 1464 while (nstack.size() != 0) { | |
| 1465 Node* n = nstack.pop(); | |
| 1466 uint cnt = n->req(); | |
| 1467 for (uint i = 1; i < cnt; i++) { // Only data paths | |
| 1468 Node* m = n->in(i); | |
| 1469 if (m == (Node*)this) { | |
| 1470 return true; // Data loop | |
| 1471 } | |
| 1472 if (m != NULL && !m->is_dead_loop_safe()) { // Only look for unsafe cases. | |
| 1473 if (!visited.test_set(m->_idx)) | |
| 1474 nstack.push(m); | |
| 1475 } | |
| 1476 } | |
| 1477 } | |
| 1478 return false; // The phi is not reachable from its inputs | |
| 1479 } | |
| 1480 | |
| 1481 | |
| 1482 //------------------------------Ideal------------------------------------------ | |
| 1483 // Return a node which is more "ideal" than the current node. Must preserve | |
| 1484 // the CFG, but we can still strip out dead paths. | |
| 1485 Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) { | |
| 1486 // The next should never happen after 6297035 fix. | |
| 1487 if( is_copy() ) // Already degraded to a Copy ? | |
| 1488 return NULL; // No change | |
| 1489 | |
| 1490 Node *r = in(0); // RegionNode | |
| 1491 assert(r->in(0) == NULL || !r->in(0)->is_Root(), "not a specially hidden merge"); | |
| 1492 | |
| 1493 // Note: During parsing, phis are often transformed before their regions. | |
| 1494 // This means we have to use type_or_null to defend against untyped regions. | |
| 1495 if( phase->type_or_null(r) == Type::TOP ) // Dead code? | |
| 1496 return NULL; // No change | |
| 1497 | |
| 1498 Node *top = phase->C->top(); | |
| 1499 | |
| 1500 // The are 2 situations when only one valid phi's input is left | |
| 1501 // (in addition to Region input). | |
| 1502 // One: region is not loop - replace phi with this input. | |
| 1503 // Two: region is loop - replace phi with top since this data path is dead | |
| 1504 // and we need to break the dead data loop. | |
| 1505 Node* progress = NULL; // Record if any progress made | |
| 1506 for( uint j = 1; j < req(); ++j ){ // For all paths in | |
| 1507 // Check unreachable control paths | |
| 1508 Node* rc = r->in(j); | |
| 1509 Node* n = in(j); // Get the input | |
| 1510 if (rc == NULL || phase->type(rc) == Type::TOP) { | |
| 1511 if (n != top) { // Not already top? | |
| 1512 set_req(j, top); // Nuke it down | |
| 1513 progress = this; // Record progress | |
| 1514 } | |
| 1515 } | |
| 1516 } | |
| 1517 | |
| 1518 Node* uin = unique_input(phase); | |
| 1519 if (uin == top) { // Simplest case: no alive inputs. | |
| 1520 if (can_reshape) // IGVN transformation | |
| 1521 return top; | |
| 1522 else | |
| 1523 return NULL; // Identity will return TOP | |
| 1524 } else if (uin != NULL) { | |
| 1525 // Only one not-NULL unique input path is left. | |
| 1526 // Determine if this input is backedge of a loop. | |
| 1527 // (Skip new phis which have no uses and dead regions). | |
| 1528 if( outcnt() > 0 && r->in(0) != NULL ) { | |
| 1529 // First, take the short cut when we know it is a loop and | |
| 1530 // the EntryControl data path is dead. | |
| 1531 assert(!r->is_Loop() || r->req() == 3, "Loop node should have 3 inputs"); | |
| 1532 // Then, check if there is a data loop when phi references itself directly | |
| 1533 // or through other data nodes. | |
| 1534 if( r->is_Loop() && !phase->eqv_uncast(uin, in(LoopNode::EntryControl)) || | |
| 1535 !r->is_Loop() && is_unsafe_data_reference(uin) ) { | |
| 1536 // Break this data loop to avoid creation of a dead loop. | |
| 1537 if (can_reshape) { | |
| 1538 return top; | |
| 1539 } else { | |
| 1540 // We can't return top if we are in Parse phase - cut inputs only | |
| 1541 // let Identity to handle the case. | |
| 1542 replace_edge(uin, top); | |
| 1543 return NULL; | |
| 1544 } | |
| 1545 } | |
| 1546 } | |
| 1547 | |
| 1548 // One unique input. | |
| 1549 debug_only(Node* ident = Identity(phase)); | |
| 1550 // The unique input must eventually be detected by the Identity call. | |
| 1551 #ifdef ASSERT | |
| 1552 if (ident != uin && !ident->is_top()) { | |
| 1553 // print this output before failing assert | |
| 1554 r->dump(3); | |
| 1555 this->dump(3); | |
| 1556 ident->dump(); | |
| 1557 uin->dump(); | |
| 1558 } | |
| 1559 #endif | |
| 1560 assert(ident == uin || ident->is_top(), "Identity must clean this up"); | |
| 1561 return NULL; | |
| 1562 } | |
| 1563 | |
| 1564 | |
| 1565 Node* opt = NULL; | |
| 1566 int true_path = is_diamond_phi(); | |
| 1567 if( true_path != 0 ) { | |
| 1568 // Check for CMove'ing identity. If it would be unsafe, | |
| 1569 // handle it here. In the safe case, let Identity handle it. | |
| 1570 Node* unsafe_id = is_cmove_id(phase, true_path); | |
| 1571 if( unsafe_id != NULL && is_unsafe_data_reference(unsafe_id) ) | |
| 1572 opt = unsafe_id; | |
| 1573 | |
| 1574 // Check for simple convert-to-boolean pattern | |
| 1575 if( opt == NULL ) | |
| 1576 opt = is_x2logic(phase, this, true_path); | |
| 1577 | |
| 1578 // Check for absolute value | |
| 1579 if( opt == NULL ) | |
| 1580 opt = is_absolute(phase, this, true_path); | |
| 1581 | |
| 1582 // Check for conditional add | |
| 1583 if( opt == NULL && can_reshape ) | |
| 1584 opt = is_cond_add(phase, this, true_path); | |
| 1585 | |
| 1586 // These 4 optimizations could subsume the phi: | |
| 1587 // have to check for a dead data loop creation. | |
| 1588 if( opt != NULL ) { | |
| 1589 if( opt == unsafe_id || is_unsafe_data_reference(opt) ) { | |
| 1590 // Found dead loop. | |
| 1591 if( can_reshape ) | |
| 1592 return top; | |
| 1593 // We can't return top if we are in Parse phase - cut inputs only | |
| 1594 // to stop further optimizations for this phi. Identity will return TOP. | |
| 1595 assert(req() == 3, "only diamond merge phi here"); | |
| 1596 set_req(1, top); | |
| 1597 set_req(2, top); | |
| 1598 return NULL; | |
| 1599 } else { | |
| 1600 return opt; | |
| 1601 } | |
| 1602 } | |
| 1603 } | |
| 1604 | |
| 1605 // Check for merging identical values and split flow paths | |
| 1606 if (can_reshape) { | |
| 1607 opt = split_flow_path(phase, this); | |
| 1608 // This optimization only modifies phi - don't need to check for dead loop. | |
| 1609 assert(opt == NULL || phase->eqv(opt, this), "do not elide phi"); | |
| 1610 if (opt != NULL) return opt; | |
| 1611 } | |
| 1612 | |
| 1613 if (in(1) != NULL && in(1)->Opcode() == Op_AddP && can_reshape) { | |
| 1614 // Try to undo Phi of AddP: | |
| 1615 // (Phi (AddP base base y) (AddP base2 base2 y)) | |
| 1616 // becomes: | |
| 1617 // newbase := (Phi base base2) | |
| 1618 // (AddP newbase newbase y) | |
| 1619 // | |
| 1620 // This occurs as a result of unsuccessful split_thru_phi and | |
| 1621 // interferes with taking advantage of addressing modes. See the | |
| 1622 // clone_shift_expressions code in matcher.cpp | |
| 1623 Node* addp = in(1); | |
| 1624 const Type* type = addp->in(AddPNode::Base)->bottom_type(); | |
| 1625 Node* y = addp->in(AddPNode::Offset); | |
| 1626 if (y != NULL && addp->in(AddPNode::Base) == addp->in(AddPNode::Address)) { | |
| 1627 // make sure that all the inputs are similar to the first one, | |
| 1628 // i.e. AddP with base == address and same offset as first AddP | |
| 1629 bool doit = true; | |
| 1630 for (uint i = 2; i < req(); i++) { | |
| 1631 if (in(i) == NULL || | |
| 1632 in(i)->Opcode() != Op_AddP || | |
| 1633 in(i)->in(AddPNode::Base) != in(i)->in(AddPNode::Address) || | |
| 1634 in(i)->in(AddPNode::Offset) != y) { | |
| 1635 doit = false; | |
| 1636 break; | |
| 1637 } | |
| 1638 // Accumulate type for resulting Phi | |
| 1639 type = type->meet(in(i)->in(AddPNode::Base)->bottom_type()); | |
| 1640 } | |
| 1641 Node* base = NULL; | |
| 1642 if (doit) { | |
| 1643 // Check for neighboring AddP nodes in a tree. | |
| 1644 // If they have a base, use that it. | |
| 1645 for (DUIterator_Fast kmax, k = this->fast_outs(kmax); k < kmax; k++) { | |
| 1646 Node* u = this->fast_out(k); | |
| 1647 if (u->is_AddP()) { | |
| 1648 Node* base2 = u->in(AddPNode::Base); | |
| 1649 if (base2 != NULL && !base2->is_top()) { | |
| 1650 if (base == NULL) | |
| 1651 base = base2; | |
| 1652 else if (base != base2) | |
| 1653 { doit = false; break; } | |
| 1654 } | |
| 1655 } | |
| 1656 } | |
| 1657 } | |
| 1658 if (doit) { | |
| 1659 if (base == NULL) { | |
| 1660 base = new (phase->C, in(0)->req()) PhiNode(in(0), type, NULL); | |
| 1661 for (uint i = 1; i < req(); i++) { | |
| 1662 base->init_req(i, in(i)->in(AddPNode::Base)); | |
| 1663 } | |
| 1664 phase->is_IterGVN()->register_new_node_with_optimizer(base); | |
| 1665 } | |
| 1666 return new (phase->C, 4) AddPNode(base, base, y); | |
| 1667 } | |
| 1668 } | |
| 1669 } | |
| 1670 | |
| 1671 // Split phis through memory merges, so that the memory merges will go away. | |
| 1672 // Piggy-back this transformation on the search for a unique input.... | |
| 1673 // It will be as if the merged memory is the unique value of the phi. | |
| 1674 // (Do not attempt this optimization unless parsing is complete. | |
| 1675 // It would make the parser's memory-merge logic sick.) | |
| 1676 // (MergeMemNode is not dead_loop_safe - need to check for dead loop.) | |
| 1677 if (progress == NULL && can_reshape && type() == Type::MEMORY) { | |
| 1678 // see if this phi should be sliced | |
| 1679 uint merge_width = 0; | |
| 1680 bool saw_self = false; | |
| 1681 for( uint i=1; i<req(); ++i ) {// For all paths in | |
| 1682 Node *ii = in(i); | |
| 1683 if (ii->is_MergeMem()) { | |
| 1684 MergeMemNode* n = ii->as_MergeMem(); | |
| 1685 merge_width = MAX2(merge_width, n->req()); | |
| 1686 saw_self = saw_self || phase->eqv(n->base_memory(), this); | |
| 1687 } | |
| 1688 } | |
| 1689 | |
| 1690 // This restriction is temporarily necessary to ensure termination: | |
| 1691 if (!saw_self && adr_type() == TypePtr::BOTTOM) merge_width = 0; | |
| 1692 | |
| 1693 if (merge_width > Compile::AliasIdxRaw) { | |
| 1694 // found at least one non-empty MergeMem | |
| 1695 const TypePtr* at = adr_type(); | |
| 1696 if (at != TypePtr::BOTTOM) { | |
| 1697 // Patch the existing phi to select an input from the merge: | |
| 1698 // Phi:AT1(...MergeMem(m0, m1, m2)...) into | |
| 1699 // Phi:AT1(...m1...) | |
| 1700 int alias_idx = phase->C->get_alias_index(at); | |
| 1701 for (uint i=1; i<req(); ++i) { | |
| 1702 Node *ii = in(i); | |
| 1703 if (ii->is_MergeMem()) { | |
| 1704 MergeMemNode* n = ii->as_MergeMem(); | |
| 1705 // compress paths and change unreachable cycles to TOP | |
| 1706 // If not, we can update the input infinitely along a MergeMem cycle | |
| 1707 // Equivalent code is in MemNode::Ideal_common | |
| 1708 Node *m = phase->transform(n); | |
| 1709 // If tranformed to a MergeMem, get the desired slice | |
| 1710 // Otherwise the returned node represents memory for every slice | |
| 1711 Node *new_mem = (m->is_MergeMem()) ? | |
| 1712 m->as_MergeMem()->memory_at(alias_idx) : m; | |
| 1713 // Update input if it is progress over what we have now | |
| 1714 if (new_mem != ii) { | |
| 1715 set_req(i, new_mem); | |
| 1716 progress = this; | |
| 1717 } | |
| 1718 } | |
| 1719 } | |
| 1720 } else { | |
| 1721 // We know that at least one MergeMem->base_memory() == this | |
| 1722 // (saw_self == true). If all other inputs also references this phi | |
| 1723 // (directly or through data nodes) - it is dead loop. | |
| 1724 bool saw_safe_input = false; | |
| 1725 for (uint j = 1; j < req(); ++j) { | |
| 1726 Node *n = in(j); | |
| 1727 if (n->is_MergeMem() && n->as_MergeMem()->base_memory() == this) | |
| 1728 continue; // skip known cases | |
| 1729 if (!is_unsafe_data_reference(n)) { | |
| 1730 saw_safe_input = true; // found safe input | |
| 1731 break; | |
| 1732 } | |
| 1733 } | |
| 1734 if (!saw_safe_input) | |
| 1735 return top; // all inputs reference back to this phi - dead loop | |
| 1736 | |
| 1737 // Phi(...MergeMem(m0, m1:AT1, m2:AT2)...) into | |
| 1738 // MergeMem(Phi(...m0...), Phi:AT1(...m1...), Phi:AT2(...m2...)) | |
| 1739 PhaseIterGVN *igvn = phase->is_IterGVN(); | |
| 1740 Node* hook = new (phase->C, 1) Node(1); | |
| 1741 PhiNode* new_base = (PhiNode*) clone(); | |
| 1742 // Must eagerly register phis, since they participate in loops. | |
| 1743 if (igvn) { | |
| 1744 igvn->register_new_node_with_optimizer(new_base); | |
| 1745 hook->add_req(new_base); | |
| 1746 } | |
| 1747 MergeMemNode* result = MergeMemNode::make(phase->C, new_base); | |
| 1748 for (uint i = 1; i < req(); ++i) { | |
| 1749 Node *ii = in(i); | |
| 1750 if (ii->is_MergeMem()) { | |
| 1751 MergeMemNode* n = ii->as_MergeMem(); | |
| 1752 for (MergeMemStream mms(result, n); mms.next_non_empty2(); ) { | |
| 1753 // If we have not seen this slice yet, make a phi for it. | |
| 1754 bool made_new_phi = false; | |
| 1755 if (mms.is_empty()) { | |
| 1756 Node* new_phi = new_base->slice_memory(mms.adr_type(phase->C)); | |
| 1757 made_new_phi = true; | |
| 1758 if (igvn) { | |
| 1759 igvn->register_new_node_with_optimizer(new_phi); | |
| 1760 hook->add_req(new_phi); | |
| 1761 } | |
| 1762 mms.set_memory(new_phi); | |
| 1763 } | |
| 1764 Node* phi = mms.memory(); | |
| 1765 assert(made_new_phi || phi->in(i) == n, "replace the i-th merge by a slice"); | |
| 1766 phi->set_req(i, mms.memory2()); | |
| 1767 } | |
| 1768 } | |
| 1769 } | |
| 1770 // Distribute all self-loops. | |
| 1771 { // (Extra braces to hide mms.) | |
| 1772 for (MergeMemStream mms(result); mms.next_non_empty(); ) { | |
| 1773 Node* phi = mms.memory(); | |
| 1774 for (uint i = 1; i < req(); ++i) { | |
| 1775 if (phi->in(i) == this) phi->set_req(i, phi); | |
| 1776 } | |
| 1777 } | |
| 1778 } | |
| 1779 // now transform the new nodes, and return the mergemem | |
| 1780 for (MergeMemStream mms(result); mms.next_non_empty(); ) { | |
| 1781 Node* phi = mms.memory(); | |
| 1782 mms.set_memory(phase->transform(phi)); | |
| 1783 } | |
| 1784 if (igvn) { // Unhook. | |
| 1785 igvn->hash_delete(hook); | |
| 1786 for (uint i = 1; i < hook->req(); i++) { | |
| 1787 hook->set_req(i, NULL); | |
| 1788 } | |
| 1789 } | |
| 1790 // Replace self with the result. | |
| 1791 return result; | |
| 1792 } | |
| 1793 } | |
|
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1794 // |
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1795 // Other optimizations on the memory chain |
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1796 // |
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1797 const TypePtr* at = adr_type(); |
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1798 for( uint i=1; i<req(); ++i ) {// For all paths in |
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1799 Node *ii = in(i); |
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1800 Node *new_in = MemNode::optimize_memory_chain(ii, at, phase); |
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1801 if (ii != new_in ) { |
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1802 set_req(i, new_in); |
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1803 progress = this; |
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1804 } |
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1805 } |
| 0 | 1806 } |
| 1807 | |
| 1808 return progress; // Return any progress | |
| 1809 } | |
| 1810 | |
| 1811 //------------------------------out_RegMask------------------------------------ | |
| 1812 const RegMask &PhiNode::in_RegMask(uint i) const { | |
| 1813 return i ? out_RegMask() : RegMask::Empty; | |
| 1814 } | |
| 1815 | |
| 1816 const RegMask &PhiNode::out_RegMask() const { | |
| 1817 uint ideal_reg = Matcher::base2reg[_type->base()]; | |
| 1818 assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" ); | |
| 1819 if( ideal_reg == 0 ) return RegMask::Empty; | |
| 1820 return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]); | |
| 1821 } | |
| 1822 | |
| 1823 #ifndef PRODUCT | |
| 1824 void PhiNode::dump_spec(outputStream *st) const { | |
| 1825 TypeNode::dump_spec(st); | |
| 1826 if (in(0) != NULL && | |
| 1827 in(0)->is_CountedLoop() && | |
| 1828 in(0)->as_CountedLoop()->phi() == this) { | |
| 1829 st->print(" #tripcount"); | |
| 1830 } | |
| 1831 } | |
| 1832 #endif | |
| 1833 | |
| 1834 | |
| 1835 //============================================================================= | |
| 1836 const Type *GotoNode::Value( PhaseTransform *phase ) const { | |
| 1837 // If the input is reachable, then we are executed. | |
| 1838 // If the input is not reachable, then we are not executed. | |
| 1839 return phase->type(in(0)); | |
| 1840 } | |
| 1841 | |
| 1842 Node *GotoNode::Identity( PhaseTransform *phase ) { | |
| 1843 return in(0); // Simple copy of incoming control | |
| 1844 } | |
| 1845 | |
| 1846 const RegMask &GotoNode::out_RegMask() const { | |
| 1847 return RegMask::Empty; | |
| 1848 } | |
| 1849 | |
| 1850 //============================================================================= | |
| 1851 const RegMask &JumpNode::out_RegMask() const { | |
| 1852 return RegMask::Empty; | |
| 1853 } | |
| 1854 | |
| 1855 //============================================================================= | |
| 1856 const RegMask &JProjNode::out_RegMask() const { | |
| 1857 return RegMask::Empty; | |
| 1858 } | |
| 1859 | |
| 1860 //============================================================================= | |
| 1861 const RegMask &CProjNode::out_RegMask() const { | |
| 1862 return RegMask::Empty; | |
| 1863 } | |
| 1864 | |
| 1865 | |
| 1866 | |
| 1867 //============================================================================= | |
| 1868 | |
| 1869 uint PCTableNode::hash() const { return Node::hash() + _size; } | |
| 1870 uint PCTableNode::cmp( const Node &n ) const | |
| 1871 { return _size == ((PCTableNode&)n)._size; } | |
| 1872 | |
| 1873 const Type *PCTableNode::bottom_type() const { | |
| 1874 const Type** f = TypeTuple::fields(_size); | |
| 1875 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; | |
| 1876 return TypeTuple::make(_size, f); | |
| 1877 } | |
| 1878 | |
| 1879 //------------------------------Value------------------------------------------ | |
| 1880 // Compute the type of the PCTableNode. If reachable it is a tuple of | |
| 1881 // Control, otherwise the table targets are not reachable | |
| 1882 const Type *PCTableNode::Value( PhaseTransform *phase ) const { | |
| 1883 if( phase->type(in(0)) == Type::CONTROL ) | |
| 1884 return bottom_type(); | |
| 1885 return Type::TOP; // All paths dead? Then so are we | |
| 1886 } | |
| 1887 | |
| 1888 //------------------------------Ideal------------------------------------------ | |
| 1889 // Return a node which is more "ideal" than the current node. Strip out | |
| 1890 // control copies | |
| 1891 Node *PCTableNode::Ideal(PhaseGVN *phase, bool can_reshape) { | |
| 1892 return remove_dead_region(phase, can_reshape) ? this : NULL; | |
| 1893 } | |
| 1894 | |
| 1895 //============================================================================= | |
| 1896 uint JumpProjNode::hash() const { | |
| 1897 return Node::hash() + _dest_bci; | |
| 1898 } | |
| 1899 | |
| 1900 uint JumpProjNode::cmp( const Node &n ) const { | |
| 1901 return ProjNode::cmp(n) && | |
| 1902 _dest_bci == ((JumpProjNode&)n)._dest_bci; | |
| 1903 } | |
| 1904 | |
| 1905 #ifndef PRODUCT | |
| 1906 void JumpProjNode::dump_spec(outputStream *st) const { | |
| 1907 ProjNode::dump_spec(st); | |
| 1908 st->print("@bci %d ",_dest_bci); | |
| 1909 } | |
| 1910 #endif | |
| 1911 | |
| 1912 //============================================================================= | |
| 1913 //------------------------------Value------------------------------------------ | |
| 1914 // Check for being unreachable, or for coming from a Rethrow. Rethrow's cannot | |
| 1915 // have the default "fall_through_index" path. | |
| 1916 const Type *CatchNode::Value( PhaseTransform *phase ) const { | |
| 1917 // Unreachable? Then so are all paths from here. | |
| 1918 if( phase->type(in(0)) == Type::TOP ) return Type::TOP; | |
| 1919 // First assume all paths are reachable | |
| 1920 const Type** f = TypeTuple::fields(_size); | |
| 1921 for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; | |
| 1922 // Identify cases that will always throw an exception | |
| 1923 // () rethrow call | |
| 1924 // () virtual or interface call with NULL receiver | |
| 1925 // () call is a check cast with incompatible arguments | |
| 1926 if( in(1)->is_Proj() ) { | |
| 1927 Node *i10 = in(1)->in(0); | |
| 1928 if( i10->is_Call() ) { | |
| 1929 CallNode *call = i10->as_Call(); | |
| 1930 // Rethrows always throw exceptions, never return | |
| 1931 if (call->entry_point() == OptoRuntime::rethrow_stub()) { | |
| 1932 f[CatchProjNode::fall_through_index] = Type::TOP; | |
| 1933 } else if( call->req() > TypeFunc::Parms ) { | |
| 1934 const Type *arg0 = phase->type( call->in(TypeFunc::Parms) ); | |
| 1935 // Check for null reciever to virtual or interface calls | |
| 1936 if( call->is_CallDynamicJava() && | |
| 1937 arg0->higher_equal(TypePtr::NULL_PTR) ) { | |
| 1938 f[CatchProjNode::fall_through_index] = Type::TOP; | |
| 1939 } | |
| 1940 } // End of if not a runtime stub | |
| 1941 } // End of if have call above me | |
| 1942 } // End of slot 1 is not a projection | |
| 1943 return TypeTuple::make(_size, f); | |
| 1944 } | |
| 1945 | |
| 1946 //============================================================================= | |
| 1947 uint CatchProjNode::hash() const { | |
| 1948 return Node::hash() + _handler_bci; | |
| 1949 } | |
| 1950 | |
| 1951 | |
| 1952 uint CatchProjNode::cmp( const Node &n ) const { | |
| 1953 return ProjNode::cmp(n) && | |
| 1954 _handler_bci == ((CatchProjNode&)n)._handler_bci; | |
| 1955 } | |
| 1956 | |
| 1957 | |
| 1958 //------------------------------Identity--------------------------------------- | |
| 1959 // If only 1 target is possible, choose it if it is the main control | |
| 1960 Node *CatchProjNode::Identity( PhaseTransform *phase ) { | |
| 1961 // If my value is control and no other value is, then treat as ID | |
| 1962 const TypeTuple *t = phase->type(in(0))->is_tuple(); | |
| 1963 if (t->field_at(_con) != Type::CONTROL) return this; | |
| 1964 // If we remove the last CatchProj and elide the Catch/CatchProj, then we | |
| 1965 // also remove any exception table entry. Thus we must know the call | |
| 1966 // feeding the Catch will not really throw an exception. This is ok for | |
| 1967 // the main fall-thru control (happens when we know a call can never throw | |
| 1968 // an exception) or for "rethrow", because a further optimnization will | |
| 1969 // yank the rethrow (happens when we inline a function that can throw an | |
| 1970 // exception and the caller has no handler). Not legal, e.g., for passing | |
| 1971 // a NULL receiver to a v-call, or passing bad types to a slow-check-cast. | |
| 1972 // These cases MUST throw an exception via the runtime system, so the VM | |
| 1973 // will be looking for a table entry. | |
| 1974 Node *proj = in(0)->in(1); // Expect a proj feeding CatchNode | |
| 1975 CallNode *call; | |
| 1976 if (_con != TypeFunc::Control && // Bail out if not the main control. | |
| 1977 !(proj->is_Proj() && // AND NOT a rethrow | |
| 1978 proj->in(0)->is_Call() && | |
| 1979 (call = proj->in(0)->as_Call()) && | |
| 1980 call->entry_point() == OptoRuntime::rethrow_stub())) | |
| 1981 return this; | |
| 1982 | |
| 1983 // Search for any other path being control | |
| 1984 for (uint i = 0; i < t->cnt(); i++) { | |
| 1985 if (i != _con && t->field_at(i) == Type::CONTROL) | |
| 1986 return this; | |
| 1987 } | |
| 1988 // Only my path is possible; I am identity on control to the jump | |
| 1989 return in(0)->in(0); | |
| 1990 } | |
| 1991 | |
| 1992 | |
| 1993 #ifndef PRODUCT | |
| 1994 void CatchProjNode::dump_spec(outputStream *st) const { | |
| 1995 ProjNode::dump_spec(st); | |
| 1996 st->print("@bci %d ",_handler_bci); | |
| 1997 } | |
| 1998 #endif | |
| 1999 | |
| 2000 //============================================================================= | |
| 2001 //------------------------------Identity--------------------------------------- | |
| 2002 // Check for CreateEx being Identity. | |
| 2003 Node *CreateExNode::Identity( PhaseTransform *phase ) { | |
| 2004 if( phase->type(in(1)) == Type::TOP ) return in(1); | |
| 2005 if( phase->type(in(0)) == Type::TOP ) return in(0); | |
| 2006 // We only come from CatchProj, unless the CatchProj goes away. | |
| 2007 // If the CatchProj is optimized away, then we just carry the | |
| 2008 // exception oop through. | |
| 2009 CallNode *call = in(1)->in(0)->as_Call(); | |
| 2010 | |
| 2011 return ( in(0)->is_CatchProj() && in(0)->in(0)->in(1) == in(1) ) | |
| 2012 ? this | |
| 2013 : call->in(TypeFunc::Parms); | |
| 2014 } | |
| 2015 | |
| 2016 //============================================================================= | |
| 2017 #ifndef PRODUCT | |
| 2018 void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const { | |
| 2019 st->print("%s", Name()); | |
| 2020 } | |
| 2021 #endif |