1 /* 2 * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "memory/allocation.inline.hpp" 27 #include "opto/callnode.hpp" 28 #include "opto/loopnode.hpp" 29 #include "opto/movenode.hpp" 30 #include "opto/valuetypenode.hpp" 31 32 33 //------------------------------split_thru_region------------------------------ 34 // Split Node 'n' through merge point. 35 Node *PhaseIdealLoop::split_thru_region( Node *n, Node *region ) { 36 uint wins = 0; 37 assert( n->is_CFG(), "" ); 38 assert( region->is_Region(), "" ); 39 Node *r = new RegionNode( region->req() ); 40 IdealLoopTree *loop = get_loop( n ); 41 for( uint i = 1; i < region->req(); i++ ) { 42 Node *x = n->clone(); 43 Node *in0 = n->in(0); 44 if( in0->in(0) == region ) x->set_req( 0, in0->in(i) ); 45 for( uint j = 1; j < n->req(); j++ ) { 46 Node *in = n->in(j); 47 if( get_ctrl(in) == region ) 48 x->set_req( j, in->in(i) ); 49 } 50 _igvn.register_new_node_with_optimizer(x); 51 set_loop(x, loop); 52 set_idom(x, x->in(0), dom_depth(x->in(0))+1); 53 r->init_req(i, x); 54 } 55 56 // Record region 57 r->set_req(0,region); // Not a TRUE RegionNode 58 _igvn.register_new_node_with_optimizer(r); 59 set_loop(r, loop); 60 if( !loop->_child ) 61 loop->_body.push(r); 62 return r; 63 } 64 65 //------------------------------split_up--------------------------------------- 66 // Split block-local op up through the phis to empty the current block 67 bool PhaseIdealLoop::split_up( Node *n, Node *blk1, Node *blk2 ) { 68 if( n->is_CFG() ) { 69 assert( n->in(0) != blk1, "Lousy candidate for split-if" ); 70 return false; 71 } 72 if( get_ctrl(n) != blk1 && get_ctrl(n) != blk2 ) 73 return false; // Not block local 74 if( n->is_Phi() ) return false; // Local PHIs are expected 75 76 // Recursively split-up inputs 77 for (uint i = 1; i < n->req(); i++) { 78 if( split_up( n->in(i), blk1, blk2 ) ) { 79 // Got split recursively and self went dead? 80 if (n->outcnt() == 0) 81 _igvn.remove_dead_node(n); 82 return true; 83 } 84 } 85 86 // Check for needing to clone-up a compare. Can't do that, it forces 87 // another (nested) split-if transform. Instead, clone it "down". 88 if( n->is_Cmp() ) { 89 assert(get_ctrl(n) == blk2 || get_ctrl(n) == blk1, "must be in block with IF"); 90 // Check for simple Cmp/Bool/CMove which we can clone-up. Cmp/Bool/CMove 91 // sequence can have no other users and it must all reside in the split-if 92 // block. Non-simple Cmp/Bool/CMove sequences are 'cloned-down' below - 93 // private, per-use versions of the Cmp and Bool are made. These sink to 94 // the CMove block. If the CMove is in the split-if block, then in the 95 // next iteration this will become a simple Cmp/Bool/CMove set to clone-up. 96 Node *bol, *cmov; 97 if( !(n->outcnt() == 1 && n->unique_out()->is_Bool() && 98 (bol = n->unique_out()->as_Bool()) && 99 (get_ctrl(bol) == blk1 || 100 get_ctrl(bol) == blk2) && 101 bol->outcnt() == 1 && 102 bol->unique_out()->is_CMove() && 103 (cmov = bol->unique_out()->as_CMove()) && 104 (get_ctrl(cmov) == blk1 || 105 get_ctrl(cmov) == blk2) ) ) { 106 107 // Must clone down 108 #ifndef PRODUCT 109 if( PrintOpto && VerifyLoopOptimizations ) { 110 tty->print("Cloning down: "); 111 n->dump(); 112 } 113 #endif 114 // Clone down any block-local BoolNode uses of this CmpNode 115 for (DUIterator i = n->outs(); n->has_out(i); i++) { 116 Node* bol = n->out(i); 117 assert( bol->is_Bool(), "" ); 118 if (bol->outcnt() == 1) { 119 Node* use = bol->unique_out(); 120 if (use->Opcode() == Op_Opaque4) { 121 if (use->outcnt() == 1) { 122 Node* iff = use->unique_out(); 123 assert(iff->is_If(), "unexpected node type"); 124 Node *use_c = iff->in(0); 125 if (use_c == blk1 || use_c == blk2) { 126 continue; 127 } 128 } 129 } else { 130 // We might see an Opaque1 from a loop limit check here 131 assert(use->is_If() || use->is_CMove() || use->Opcode() == Op_Opaque1, "unexpected node type"); 132 Node *use_c = use->is_If() ? use->in(0) : get_ctrl(use); 133 if (use_c == blk1 || use_c == blk2) { 134 assert(use->is_CMove(), "unexpected node type"); 135 continue; 136 } 137 } 138 } 139 if (get_ctrl(bol) == blk1 || get_ctrl(bol) == blk2) { 140 // Recursively sink any BoolNode 141 #ifndef PRODUCT 142 if( PrintOpto && VerifyLoopOptimizations ) { 143 tty->print("Cloning down: "); 144 bol->dump(); 145 } 146 #endif 147 for (DUIterator j = bol->outs(); bol->has_out(j); j++) { 148 Node* u = bol->out(j); 149 // Uses are either IfNodes, CMoves or Opaque4 150 if (u->Opcode() == Op_Opaque4) { 151 assert(u->in(1) == bol, "bad input"); 152 for (DUIterator_Last kmin, k = u->last_outs(kmin); k >= kmin; --k) { 153 Node* iff = u->last_out(k); 154 assert(iff->is_If() || iff->is_CMove(), "unexpected node type"); 155 assert( iff->in(1) == u, "" ); 156 // Get control block of either the CMove or the If input 157 Node *iff_ctrl = iff->is_If() ? iff->in(0) : get_ctrl(iff); 158 Node *x1 = bol->clone(); 159 Node *x2 = u->clone(); 160 register_new_node(x1, iff_ctrl); 161 register_new_node(x2, iff_ctrl); 162 _igvn.replace_input_of(x2, 1, x1); 163 _igvn.replace_input_of(iff, 1, x2); 164 } 165 _igvn.remove_dead_node(u); 166 --j; 167 } else { 168 // We might see an Opaque1 from a loop limit check here 169 assert(u->is_If() || u->is_CMove() || u->Opcode() == Op_Opaque1, "unexpected node type"); 170 assert(u->in(1) == bol, ""); 171 // Get control block of either the CMove or the If input 172 Node *u_ctrl = u->is_If() ? u->in(0) : get_ctrl(u); 173 assert((u_ctrl != blk1 && u_ctrl != blk2) || u->is_CMove(), "won't converge"); 174 Node *x = bol->clone(); 175 register_new_node(x, u_ctrl); 176 _igvn.replace_input_of(u, 1, x); 177 --j; 178 } 179 } 180 _igvn.remove_dead_node(bol); 181 --i; 182 } 183 } 184 // Clone down this CmpNode 185 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; --j) { 186 Node* bol = n->last_out(j); 187 assert( bol->in(1) == n, "" ); 188 Node *x = n->clone(); 189 register_new_node(x, get_ctrl(bol)); 190 _igvn.replace_input_of(bol, 1, x); 191 } 192 _igvn.remove_dead_node( n ); 193 194 return true; 195 } 196 } 197 198 // See if splitting-up a Store. Any anti-dep loads must go up as 199 // well. An anti-dep load might be in the wrong block, because in 200 // this particular layout/schedule we ignored anti-deps and allow 201 // memory to be alive twice. This only works if we do the same 202 // operations on anti-dep loads as we do their killing stores. 203 if( n->is_Store() && n->in(MemNode::Memory)->in(0) == n->in(0) ) { 204 // Get store's memory slice 205 int alias_idx = C->get_alias_index(_igvn.type(n->in(MemNode::Address))->is_ptr()); 206 207 // Get memory-phi anti-dep loads will be using 208 Node *memphi = n->in(MemNode::Memory); 209 assert( memphi->is_Phi(), "" ); 210 // Hoist any anti-dep load to the splitting block; 211 // it will then "split-up". 212 for (DUIterator_Fast imax,i = memphi->fast_outs(imax); i < imax; i++) { 213 Node *load = memphi->fast_out(i); 214 if( load->is_Load() && alias_idx == C->get_alias_index(_igvn.type(load->in(MemNode::Address))->is_ptr()) ) 215 set_ctrl(load,blk1); 216 } 217 } 218 219 // Found some other Node; must clone it up 220 #ifndef PRODUCT 221 if( PrintOpto && VerifyLoopOptimizations ) { 222 tty->print("Cloning up: "); 223 n->dump(); 224 } 225 #endif 226 227 // ConvI2L may have type information on it which becomes invalid if 228 // it moves up in the graph so change any clones so widen the type 229 // to TypeLong::INT when pushing it up. 230 const Type* rtype = NULL; 231 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::INT) { 232 rtype = TypeLong::INT; 233 } 234 235 // Value types should not be split through Phis but each value input 236 // needs to be merged individually. At this point, value types should 237 // only be used by AllocateNodes. Try to remove redundant allocations 238 // and unlink the now dead value type node. 239 if (n->is_ValueType()) { 240 n->as_ValueType()->remove_redundant_allocations(&_igvn, this); 241 return true; // n is now dead 242 } 243 244 // Now actually split-up this guy. One copy per control path merging. 245 Node *phi = PhiNode::make_blank(blk1, n); 246 for( uint j = 1; j < blk1->req(); j++ ) { 247 Node *x = n->clone(); 248 // Widen the type of the ConvI2L when pushing up. 249 if (rtype != NULL) x->as_Type()->set_type(rtype); 250 if( n->in(0) && n->in(0) == blk1 ) 251 x->set_req( 0, blk1->in(j) ); 252 for( uint i = 1; i < n->req(); i++ ) { 253 Node *m = n->in(i); 254 if( get_ctrl(m) == blk1 ) { 255 assert( m->in(0) == blk1, "" ); 256 x->set_req( i, m->in(j) ); 257 } 258 } 259 register_new_node( x, blk1->in(j) ); 260 phi->init_req( j, x ); 261 } 262 // Announce phi to optimizer 263 register_new_node(phi, blk1); 264 265 // Remove cloned-up value from optimizer; use phi instead 266 _igvn.replace_node( n, phi ); 267 268 // (There used to be a self-recursive call to split_up() here, 269 // but it is not needed. All necessary forward walking is done 270 // by do_split_if() below.) 271 272 return true; 273 } 274 275 //------------------------------register_new_node------------------------------ 276 void PhaseIdealLoop::register_new_node( Node *n, Node *blk ) { 277 assert(!n->is_CFG(), "must be data node"); 278 _igvn.register_new_node_with_optimizer(n); 279 set_ctrl(n, blk); 280 IdealLoopTree *loop = get_loop(blk); 281 if( !loop->_child ) 282 loop->_body.push(n); 283 } 284 285 //------------------------------small_cache------------------------------------ 286 struct small_cache : public Dict { 287 288 small_cache() : Dict( cmpkey, hashptr ) {} 289 Node *probe( Node *use_blk ) { return (Node*)((*this)[use_blk]); } 290 void lru_insert( Node *use_blk, Node *new_def ) { Insert(use_blk,new_def); } 291 }; 292 293 //------------------------------spinup----------------------------------------- 294 // "Spin up" the dominator tree, starting at the use site and stopping when we 295 // find the post-dominating point. 296 297 // We must be at the merge point which post-dominates 'new_false' and 298 // 'new_true'. Figure out which edges into the RegionNode eventually lead up 299 // to false and which to true. Put in a PhiNode to merge values; plug in 300 // the appropriate false-arm or true-arm values. If some path leads to the 301 // original IF, then insert a Phi recursively. 302 Node *PhaseIdealLoop::spinup( Node *iff_dom, Node *new_false, Node *new_true, Node *use_blk, Node *def, small_cache *cache ) { 303 if (use_blk->is_top()) // Handle dead uses 304 return use_blk; 305 Node *prior_n = (Node*)((intptr_t)0xdeadbeef); 306 Node *n = use_blk; // Get path input 307 assert( use_blk != iff_dom, "" ); 308 // Here's the "spinup" the dominator tree loop. Do a cache-check 309 // along the way, in case we've come this way before. 310 while( n != iff_dom ) { // Found post-dominating point? 311 prior_n = n; 312 n = idom(n); // Search higher 313 Node *s = cache->probe( prior_n ); // Check cache 314 if( s ) return s; // Cache hit! 315 } 316 317 Node *phi_post; 318 if( prior_n == new_false || prior_n == new_true ) { 319 phi_post = def->clone(); 320 phi_post->set_req(0, prior_n ); 321 register_new_node(phi_post, prior_n); 322 } else { 323 // This method handles both control uses (looking for Regions) or data 324 // uses (looking for Phis). If looking for a control use, then we need 325 // to insert a Region instead of a Phi; however Regions always exist 326 // previously (the hash_find_insert below would always hit) so we can 327 // return the existing Region. 328 if( def->is_CFG() ) { 329 phi_post = prior_n; // If looking for CFG, return prior 330 } else { 331 assert( def->is_Phi(), "" ); 332 assert( prior_n->is_Region(), "must be a post-dominating merge point" ); 333 334 // Need a Phi here 335 phi_post = PhiNode::make_blank(prior_n, def); 336 // Search for both true and false on all paths till find one. 337 for( uint i = 1; i < phi_post->req(); i++ ) // For all paths 338 phi_post->init_req( i, spinup( iff_dom, new_false, new_true, prior_n->in(i), def, cache ) ); 339 Node *t = _igvn.hash_find_insert(phi_post); 340 if( t ) { // See if we already have this one 341 // phi_post will not be used, so kill it 342 _igvn.remove_dead_node(phi_post); 343 phi_post->destruct(); 344 phi_post = t; 345 } else { 346 register_new_node( phi_post, prior_n ); 347 } 348 } 349 } 350 351 // Update cache everywhere 352 prior_n = (Node*)((intptr_t)0xdeadbeef); // Reset IDOM walk 353 n = use_blk; // Get path input 354 // Spin-up the idom tree again, basically doing path-compression. 355 // Insert cache entries along the way, so that if we ever hit this 356 // point in the IDOM tree again we'll stop immediately on a cache hit. 357 while( n != iff_dom ) { // Found post-dominating point? 358 prior_n = n; 359 n = idom(n); // Search higher 360 cache->lru_insert( prior_n, phi_post ); // Fill cache 361 } // End of while not gone high enough 362 363 return phi_post; 364 } 365 366 //------------------------------find_use_block--------------------------------- 367 // Find the block a USE is in. Normally USE's are in the same block as the 368 // using instruction. For Phi-USE's, the USE is in the predecessor block 369 // along the corresponding path. 370 Node *PhaseIdealLoop::find_use_block( Node *use, Node *def, Node *old_false, Node *new_false, Node *old_true, Node *new_true ) { 371 // CFG uses are their own block 372 if( use->is_CFG() ) 373 return use; 374 375 if( use->is_Phi() ) { // Phi uses in prior block 376 // Grab the first Phi use; there may be many. 377 // Each will be handled as a separate iteration of 378 // the "while( phi->outcnt() )" loop. 379 uint j; 380 for( j = 1; j < use->req(); j++ ) 381 if( use->in(j) == def ) 382 break; 383 assert( j < use->req(), "def should be among use's inputs" ); 384 return use->in(0)->in(j); 385 } 386 // Normal (non-phi) use 387 Node *use_blk = get_ctrl(use); 388 // Some uses are directly attached to the old (and going away) 389 // false and true branches. 390 if( use_blk == old_false ) { 391 use_blk = new_false; 392 set_ctrl(use, new_false); 393 } 394 if( use_blk == old_true ) { 395 use_blk = new_true; 396 set_ctrl(use, new_true); 397 } 398 399 if (use_blk == NULL) { // He's dead, Jim 400 _igvn.replace_node(use, C->top()); 401 } 402 403 return use_blk; 404 } 405 406 //------------------------------handle_use------------------------------------- 407 // Handle uses of the merge point. Basically, split-if makes the merge point 408 // go away so all uses of the merge point must go away as well. Most block 409 // local uses have already been split-up, through the merge point. Uses from 410 // far below the merge point can't always be split up (e.g., phi-uses are 411 // pinned) and it makes too much stuff live. Instead we use a path-based 412 // solution to move uses down. 413 // 414 // If the use is along the pre-split-CFG true branch, then the new use will 415 // be from the post-split-CFG true merge point. Vice-versa for the false 416 // path. Some uses will be along both paths; then we sink the use to the 417 // post-dominating location; we may need to insert a Phi there. 418 void PhaseIdealLoop::handle_use( Node *use, Node *def, small_cache *cache, Node *region_dom, Node *new_false, Node *new_true, Node *old_false, Node *old_true ) { 419 420 Node *use_blk = find_use_block(use,def,old_false,new_false,old_true,new_true); 421 if( !use_blk ) return; // He's dead, Jim 422 423 // Walk up the dominator tree until I hit either the old IfFalse, the old 424 // IfTrue or the old If. Insert Phis where needed. 425 Node *new_def = spinup( region_dom, new_false, new_true, use_blk, def, cache ); 426 427 // Found where this USE goes. Re-point him. 428 uint i; 429 for( i = 0; i < use->req(); i++ ) 430 if( use->in(i) == def ) 431 break; 432 assert( i < use->req(), "def should be among use's inputs" ); 433 _igvn.replace_input_of(use, i, new_def); 434 } 435 436 //------------------------------do_split_if------------------------------------ 437 // Found an If getting its condition-code input from a Phi in the same block. 438 // Split thru the Region. 439 void PhaseIdealLoop::do_split_if( Node *iff ) { 440 if (PrintOpto && VerifyLoopOptimizations) { 441 tty->print_cr("Split-if"); 442 } 443 if (TraceLoopOpts) { 444 tty->print_cr("SplitIf"); 445 } 446 447 C->set_major_progress(); 448 Node *region = iff->in(0); 449 Node *region_dom = idom(region); 450 451 // We are going to clone this test (and the control flow with it) up through 452 // the incoming merge point. We need to empty the current basic block. 453 // Clone any instructions which must be in this block up through the merge 454 // point. 455 DUIterator i, j; 456 bool progress = true; 457 while (progress) { 458 progress = false; 459 for (i = region->outs(); region->has_out(i); i++) { 460 Node* n = region->out(i); 461 if( n == region ) continue; 462 // The IF to be split is OK. 463 if( n == iff ) continue; 464 if( !n->is_Phi() ) { // Found pinned memory op or such 465 if (split_up(n, region, iff)) { 466 i = region->refresh_out_pos(i); 467 progress = true; 468 } 469 continue; 470 } 471 assert( n->in(0) == region, "" ); 472 473 // Recursively split up all users of a Phi 474 for (j = n->outs(); n->has_out(j); j++) { 475 Node* m = n->out(j); 476 // If m is dead, throw it away, and declare progress 477 if (_nodes[m->_idx] == NULL) { 478 _igvn.remove_dead_node(m); 479 // fall through 480 } 481 else if (m != iff && split_up(m, region, iff)) { 482 // fall through 483 } else { 484 continue; 485 } 486 // Something unpredictable changed. 487 // Tell the iterators to refresh themselves, and rerun the loop. 488 i = region->refresh_out_pos(i); 489 j = region->refresh_out_pos(j); 490 progress = true; 491 } 492 } 493 } 494 495 // Now we have no instructions in the block containing the IF. 496 // Split the IF. 497 Node *new_iff = split_thru_region( iff, region ); 498 499 // Replace both uses of 'new_iff' with Regions merging True/False 500 // paths. This makes 'new_iff' go dead. 501 Node *old_false = NULL, *old_true = NULL; 502 Node *new_false = NULL, *new_true = NULL; 503 for (DUIterator_Last j2min, j2 = iff->last_outs(j2min); j2 >= j2min; --j2) { 504 Node *ifp = iff->last_out(j2); 505 assert( ifp->Opcode() == Op_IfFalse || ifp->Opcode() == Op_IfTrue, "" ); 506 ifp->set_req(0, new_iff); 507 Node *ifpx = split_thru_region( ifp, region ); 508 509 // Replace 'If' projection of a Region with a Region of 510 // 'If' projections. 511 ifpx->set_req(0, ifpx); // A TRUE RegionNode 512 513 // Setup dominator info 514 set_idom(ifpx, region_dom, dom_depth(region_dom) + 1); 515 516 // Check for splitting loop tails 517 if( get_loop(iff)->tail() == ifp ) 518 get_loop(iff)->_tail = ifpx; 519 520 // Replace in the graph with lazy-update mechanism 521 new_iff->set_req(0, new_iff); // hook self so it does not go dead 522 lazy_replace(ifp, ifpx); 523 new_iff->set_req(0, region); 524 525 // Record bits for later xforms 526 if( ifp->Opcode() == Op_IfFalse ) { 527 old_false = ifp; 528 new_false = ifpx; 529 } else { 530 old_true = ifp; 531 new_true = ifpx; 532 } 533 } 534 _igvn.remove_dead_node(new_iff); 535 // Lazy replace IDOM info with the region's dominator 536 lazy_replace( iff, region_dom ); 537 538 // Now make the original merge point go dead, by handling all its uses. 539 small_cache region_cache; 540 // Preload some control flow in region-cache 541 region_cache.lru_insert( new_false, new_false ); 542 region_cache.lru_insert( new_true , new_true ); 543 // Now handle all uses of the splitting block 544 for (DUIterator k = region->outs(); region->has_out(k); k++) { 545 Node* phi = region->out(k); 546 if (!phi->in(0)) { // Dead phi? Remove it 547 _igvn.remove_dead_node(phi); 548 } else if (phi == region) { // Found the self-reference 549 continue; // No roll-back of DUIterator 550 } else if (phi->is_Phi()) { // Expected common case: Phi hanging off of Region 551 assert(phi->in(0) == region, "Inconsistent graph"); 552 // Need a per-def cache. Phi represents a def, so make a cache 553 small_cache phi_cache; 554 555 // Inspect all Phi uses to make the Phi go dead 556 for (DUIterator_Last lmin, l = phi->last_outs(lmin); l >= lmin; --l) { 557 Node* use = phi->last_out(l); 558 // Compute the new DEF for this USE. New DEF depends on the path 559 // taken from the original DEF to the USE. The new DEF may be some 560 // collection of PHI's merging values from different paths. The Phis 561 // inserted depend only on the location of the USE. We use a 562 // 2-element cache to handle multiple uses from the same block. 563 handle_use(use, phi, &phi_cache, region_dom, new_false, new_true, old_false, old_true); 564 } // End of while phi has uses 565 // Remove the dead Phi 566 _igvn.remove_dead_node( phi ); 567 } else { 568 assert(phi->in(0) == region, "Inconsistent graph"); 569 // Random memory op guarded by Region. Compute new DEF for USE. 570 handle_use(phi, region, ®ion_cache, region_dom, new_false, new_true, old_false, old_true); 571 } 572 // Every path above deletes a use of the region, except for the region 573 // self-cycle (which is needed by handle_use calling find_use_block 574 // calling get_ctrl calling get_ctrl_no_update looking for dead 575 // regions). So roll back the DUIterator innards. 576 --k; 577 } // End of while merge point has phis 578 579 assert(region->outcnt() == 1, "Only self reference should remain"); // Just Self on the Region 580 region->set_req(0, NULL); // Break the self-cycle 581 582 // Any leftover bits in the splitting block must not have depended on local 583 // Phi inputs (these have already been split-up). Hence it's safe to hoist 584 // these guys to the dominating point. 585 lazy_replace( region, region_dom ); 586 #ifndef PRODUCT 587 if( VerifyLoopOptimizations ) verify(); 588 #endif 589 }