1 /*
   2  * Copyright (c) 1998, 2015, 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/block.hpp"
  28 #include "opto/c2compiler.hpp"
  29 #include "opto/callnode.hpp"
  30 #include "opto/cfgnode.hpp"
  31 #include "opto/machnode.hpp"
  32 #include "opto/runtime.hpp"
  33 #if defined AD_MD_HPP
  34 # include AD_MD_HPP
  35 #elif defined TARGET_ARCH_MODEL_x86_32
  36 # include "adfiles/ad_x86_32.hpp"
  37 #elif defined TARGET_ARCH_MODEL_x86_64
  38 # include "adfiles/ad_x86_64.hpp"
  39 #elif defined TARGET_ARCH_MODEL_sparc
  40 # include "adfiles/ad_sparc.hpp"
  41 #elif defined TARGET_ARCH_MODEL_zero
  42 # include "adfiles/ad_zero.hpp"
  43 #elif defined TARGET_ARCH_MODEL_ppc_64
  44 # include "adfiles/ad_ppc_64.hpp"
  45 #elif defined TARGET_ARCH_MODEL_aarch32
  46 # include "adfiles/ad_aarch32.hpp"
  47 #endif
  48 
  49 // Optimization - Graph Style
  50 
  51 // Check whether val is not-null-decoded compressed oop,
  52 // i.e. will grab into the base of the heap if it represents NULL.
  53 static bool accesses_heap_base_zone(Node *val) {
  54   if (Universe::narrow_oop_base() != NULL) { // Implies UseCompressedOops.
  55     if (val && val->is_Mach()) {
  56       if (val->as_Mach()->ideal_Opcode() == Op_DecodeN) {
  57         // This assumes all Decodes with TypePtr::NotNull are matched to nodes that
  58         // decode NULL to point to the heap base (Decode_NN).
  59         if (val->bottom_type()->is_oopptr()->ptr() == TypePtr::NotNull) {
  60           return true;
  61         }
  62       }
  63       // Must recognize load operation with Decode matched in memory operand.
  64       // We should not reach here exept for PPC/AIX, as os::zero_page_read_protected()
  65       // returns true everywhere else. On PPC, no such memory operands
  66       // exist, therefore we did not yet implement a check for such operands.
  67       NOT_AIX(Unimplemented());
  68     }
  69   }
  70   return false;
  71 }
  72 
  73 static bool needs_explicit_null_check_for_read(Node *val) {
  74   // On some OSes (AIX) the page at address 0 is only write protected.
  75   // If so, only Store operations will trap.
  76   if (os::zero_page_read_protected()) {
  77     return false;  // Implicit null check will work.
  78   }
  79   // Also a read accessing the base of a heap-based compressed heap will trap.
  80   if (accesses_heap_base_zone(val) &&                    // Hits the base zone page.
  81       Universe::narrow_oop_use_implicit_null_checks()) { // Base zone page is protected.
  82     return false;
  83   }
  84 
  85   return true;
  86 }
  87 
  88 //------------------------------implicit_null_check----------------------------
  89 // Detect implicit-null-check opportunities.  Basically, find NULL checks
  90 // with suitable memory ops nearby.  Use the memory op to do the NULL check.
  91 // I can generate a memory op if there is not one nearby.
  92 // The proj is the control projection for the not-null case.
  93 // The val is the pointer being checked for nullness or
  94 // decodeHeapOop_not_null node if it did not fold into address.
  95 void PhaseCFG::implicit_null_check(Block* block, Node *proj, Node *val, int allowed_reasons) {
  96   // Assume if null check need for 0 offset then always needed
  97   // Intel solaris doesn't support any null checks yet and no
  98   // mechanism exists (yet) to set the switches at an os_cpu level
  99   if( !ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(0)) return;
 100 
 101   // Make sure the ptr-is-null path appears to be uncommon!
 102   float f = block->end()->as_MachIf()->_prob;
 103   if( proj->Opcode() == Op_IfTrue ) f = 1.0f - f;
 104   if( f > PROB_UNLIKELY_MAG(4) ) return;
 105 
 106   uint bidx = 0;                // Capture index of value into memop
 107   bool was_store;               // Memory op is a store op
 108 
 109   // Get the successor block for if the test ptr is non-null
 110   Block* not_null_block;  // this one goes with the proj
 111   Block* null_block;
 112   if (block->get_node(block->number_of_nodes()-1) == proj) {
 113     null_block     = block->_succs[0];
 114     not_null_block = block->_succs[1];
 115   } else {
 116     assert(block->get_node(block->number_of_nodes()-2) == proj, "proj is one or the other");
 117     not_null_block = block->_succs[0];
 118     null_block     = block->_succs[1];
 119   }
 120   while (null_block->is_Empty() == Block::empty_with_goto) {
 121     null_block     = null_block->_succs[0];
 122   }
 123 
 124   // Search the exception block for an uncommon trap.
 125   // (See Parse::do_if and Parse::do_ifnull for the reason
 126   // we need an uncommon trap.  Briefly, we need a way to
 127   // detect failure of this optimization, as in 6366351.)
 128   {
 129     bool found_trap = false;
 130     for (uint i1 = 0; i1 < null_block->number_of_nodes(); i1++) {
 131       Node* nn = null_block->get_node(i1);
 132       if (nn->is_MachCall() &&
 133           nn->as_MachCall()->entry_point() == SharedRuntime::uncommon_trap_blob()->entry_point()) {
 134         const Type* trtype = nn->in(TypeFunc::Parms)->bottom_type();
 135         if (trtype->isa_int() && trtype->is_int()->is_con()) {
 136           jint tr_con = trtype->is_int()->get_con();
 137           Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(tr_con);
 138           Deoptimization::DeoptAction action = Deoptimization::trap_request_action(tr_con);
 139           assert((int)reason < (int)BitsPerInt, "recode bit map");
 140           if (is_set_nth_bit(allowed_reasons, (int) reason)
 141               && action != Deoptimization::Action_none) {
 142             // This uncommon trap is sure to recompile, eventually.
 143             // When that happens, C->too_many_traps will prevent
 144             // this transformation from happening again.
 145             found_trap = true;
 146           }
 147         }
 148         break;
 149       }
 150     }
 151     if (!found_trap) {
 152       // We did not find an uncommon trap.
 153       return;
 154     }
 155   }
 156 
 157   // Check for decodeHeapOop_not_null node which did not fold into address
 158   bool is_decoden = ((intptr_t)val) & 1;
 159   val = (Node*)(((intptr_t)val) & ~1);
 160 
 161   assert(!is_decoden || (val->in(0) == NULL) && val->is_Mach() &&
 162          (val->as_Mach()->ideal_Opcode() == Op_DecodeN), "sanity");
 163 
 164   // Search the successor block for a load or store who's base value is also
 165   // the tested value.  There may be several.
 166   Node_List *out = new Node_List(Thread::current()->resource_area());
 167   MachNode *best = NULL;        // Best found so far
 168   for (DUIterator i = val->outs(); val->has_out(i); i++) {
 169     Node *m = val->out(i);
 170     if( !m->is_Mach() ) continue;
 171     MachNode *mach = m->as_Mach();
 172     was_store = false;
 173     int iop = mach->ideal_Opcode();
 174     switch( iop ) {
 175     case Op_LoadB:
 176     case Op_LoadUB:
 177     case Op_LoadUS:
 178     case Op_LoadD:
 179     case Op_LoadF:
 180     case Op_LoadI:
 181     case Op_LoadL:
 182     case Op_LoadP:
 183     case Op_LoadN:
 184     case Op_LoadS:
 185     case Op_LoadKlass:
 186     case Op_LoadNKlass:
 187     case Op_LoadRange:
 188     case Op_LoadD_unaligned:
 189     case Op_LoadL_unaligned:
 190       assert(mach->in(2) == val, "should be address");
 191       break;
 192     case Op_StoreB:
 193     case Op_StoreC:
 194     case Op_StoreCM:
 195     case Op_StoreD:
 196     case Op_StoreF:
 197     case Op_StoreI:
 198     case Op_StoreL:
 199     case Op_StoreP:
 200     case Op_StoreN:
 201     case Op_StoreNKlass:
 202       was_store = true;         // Memory op is a store op
 203       // Stores will have their address in slot 2 (memory in slot 1).
 204       // If the value being nul-checked is in another slot, it means we
 205       // are storing the checked value, which does NOT check the value!
 206       if( mach->in(2) != val ) continue;
 207       break;                    // Found a memory op?
 208     case Op_StrComp:
 209     case Op_StrEquals:
 210     case Op_StrIndexOf:
 211     case Op_AryEq:
 212     case Op_EncodeISOArray:
 213       // Not a legit memory op for implicit null check regardless of
 214       // embedded loads
 215       continue;
 216     default:                    // Also check for embedded loads
 217       if( !mach->needs_anti_dependence_check() )
 218         continue;               // Not an memory op; skip it
 219       if( must_clone[iop] ) {
 220         // Do not move nodes which produce flags because
 221         // RA will try to clone it to place near branch and
 222         // it will cause recompilation, see clone_node().
 223         continue;
 224       }
 225       {
 226         // Check that value is used in memory address in
 227         // instructions with embedded load (CmpP val1,(val2+off)).
 228         Node* base;
 229         Node* index;
 230         const MachOper* oper = mach->memory_inputs(base, index);
 231         if (oper == NULL || oper == (MachOper*)-1) {
 232           continue;             // Not an memory op; skip it
 233         }
 234         if (val == base ||
 235             val == index && val->bottom_type()->isa_narrowoop()) {
 236           break;                // Found it
 237         } else {
 238           continue;             // Skip it
 239         }
 240       }
 241       break;
 242     }
 243 
 244     // On some OSes (AIX) the page at address 0 is only write protected.
 245     // If so, only Store operations will trap.
 246     // But a read accessing the base of a heap-based compressed heap will trap.
 247     if (!was_store && needs_explicit_null_check_for_read(val)) {
 248       continue;
 249     }
 250 
 251     // Check that node's control edge is not-null block's head or dominates it,
 252     // otherwise we can't hoist it because there are other control dependencies.
 253     Node* ctrl = mach->in(0);
 254     if (ctrl != NULL && !(ctrl == not_null_block->head() ||
 255         get_block_for_node(ctrl)->dominates(not_null_block))) {
 256       continue;
 257     }
 258 
 259     // check if the offset is not too high for implicit exception
 260     {
 261       intptr_t offset = 0;
 262       const TypePtr *adr_type = NULL;  // Do not need this return value here
 263       const Node* base = mach->get_base_and_disp(offset, adr_type);
 264       if (base == NULL || base == NodeSentinel) {
 265         // Narrow oop address doesn't have base, only index
 266         if( val->bottom_type()->isa_narrowoop() &&
 267             MacroAssembler::needs_explicit_null_check(offset) )
 268           continue;             // Give up if offset is beyond page size
 269         // cannot reason about it; is probably not implicit null exception
 270       } else {
 271         const TypePtr* tptr;
 272         if (UseCompressedOops && (Universe::narrow_oop_shift() == 0 ||
 273                                   Universe::narrow_klass_shift() == 0)) {
 274           // 32-bits narrow oop can be the base of address expressions
 275           tptr = base->get_ptr_type();
 276         } else {
 277           // only regular oops are expected here
 278           tptr = base->bottom_type()->is_ptr();
 279         }
 280         // Give up if offset is not a compile-time constant
 281         if( offset == Type::OffsetBot || tptr->_offset == Type::OffsetBot )
 282           continue;
 283         offset += tptr->_offset; // correct if base is offseted
 284         if( MacroAssembler::needs_explicit_null_check(offset) )
 285           continue;             // Give up is reference is beyond 4K page size
 286       }
 287     }
 288 
 289     // Check ctrl input to see if the null-check dominates the memory op
 290     Block *cb = get_block_for_node(mach);
 291     cb = cb->_idom;             // Always hoist at least 1 block
 292     if( !was_store ) {          // Stores can be hoisted only one block
 293       while( cb->_dom_depth > (block->_dom_depth + 1))
 294         cb = cb->_idom;         // Hoist loads as far as we want
 295       // The non-null-block should dominate the memory op, too. Live
 296       // range spilling will insert a spill in the non-null-block if it is
 297       // needs to spill the memory op for an implicit null check.
 298       if (cb->_dom_depth == (block->_dom_depth + 1)) {
 299         if (cb != not_null_block) continue;
 300         cb = cb->_idom;
 301       }
 302     }
 303     if( cb != block ) continue;
 304 
 305     // Found a memory user; see if it can be hoisted to check-block
 306     uint vidx = 0;              // Capture index of value into memop
 307     uint j;
 308     for( j = mach->req()-1; j > 0; j-- ) {
 309       if( mach->in(j) == val ) {
 310         vidx = j;
 311         // Ignore DecodeN val which could be hoisted to where needed.
 312         if( is_decoden ) continue;
 313       }
 314       // Block of memory-op input
 315       Block *inb = get_block_for_node(mach->in(j));
 316       Block *b = block;          // Start from nul check
 317       while( b != inb && b->_dom_depth > inb->_dom_depth )
 318         b = b->_idom;           // search upwards for input
 319       // See if input dominates null check
 320       if( b != inb )
 321         break;
 322     }
 323     if( j > 0 )
 324       continue;
 325     Block *mb = get_block_for_node(mach);
 326     // Hoisting stores requires more checks for the anti-dependence case.
 327     // Give up hoisting if we have to move the store past any load.
 328     if( was_store ) {
 329       Block *b = mb;            // Start searching here for a local load
 330       // mach use (faulting) trying to hoist
 331       // n might be blocker to hoisting
 332       while( b != block ) {
 333         uint k;
 334         for( k = 1; k < b->number_of_nodes(); k++ ) {
 335           Node *n = b->get_node(k);
 336           if( n->needs_anti_dependence_check() &&
 337               n->in(LoadNode::Memory) == mach->in(StoreNode::Memory) )
 338             break;              // Found anti-dependent load
 339         }
 340         if( k < b->number_of_nodes() )
 341           break;                // Found anti-dependent load
 342         // Make sure control does not do a merge (would have to check allpaths)
 343         if( b->num_preds() != 2 ) break;
 344         b = get_block_for_node(b->pred(1)); // Move up to predecessor block
 345       }
 346       if( b != block ) continue;
 347     }
 348 
 349     // Make sure this memory op is not already being used for a NullCheck
 350     Node *e = mb->end();
 351     if( e->is_MachNullCheck() && e->in(1) == mach )
 352       continue;                 // Already being used as a NULL check
 353 
 354     // Found a candidate!  Pick one with least dom depth - the highest
 355     // in the dom tree should be closest to the null check.
 356     if (best == NULL || get_block_for_node(mach)->_dom_depth < get_block_for_node(best)->_dom_depth) {
 357       best = mach;
 358       bidx = vidx;
 359     }
 360   }
 361   // No candidate!
 362   if (best == NULL) {
 363     return;
 364   }
 365 
 366   // ---- Found an implicit null check
 367   extern int implicit_null_checks;
 368   implicit_null_checks++;
 369 
 370   if( is_decoden ) {
 371     // Check if we need to hoist decodeHeapOop_not_null first.
 372     Block *valb = get_block_for_node(val);
 373     if( block != valb && block->_dom_depth < valb->_dom_depth ) {
 374       // Hoist it up to the end of the test block.
 375       valb->find_remove(val);
 376       block->add_inst(val);
 377       map_node_to_block(val, block);
 378       // DecodeN on x86 may kill flags. Check for flag-killing projections
 379       // that also need to be hoisted.
 380       for (DUIterator_Fast jmax, j = val->fast_outs(jmax); j < jmax; j++) {
 381         Node* n = val->fast_out(j);
 382         if( n->is_MachProj() ) {
 383           get_block_for_node(n)->find_remove(n);
 384           block->add_inst(n);
 385           map_node_to_block(n, block);
 386         }
 387       }
 388     }
 389   }
 390   // Hoist the memory candidate up to the end of the test block.
 391   Block *old_block = get_block_for_node(best);
 392   old_block->find_remove(best);
 393   block->add_inst(best);
 394   map_node_to_block(best, block);
 395 
 396   // Move the control dependence if it is pinned to not-null block.
 397   // Don't change it in other cases: NULL or dominating control.
 398   if (best->in(0) == not_null_block->head()) {
 399     // Set it to control edge of null check.
 400     best->set_req(0, proj->in(0)->in(0));
 401   }
 402 
 403   // Check for flag-killing projections that also need to be hoisted
 404   // Should be DU safe because no edge updates.
 405   for (DUIterator_Fast jmax, j = best->fast_outs(jmax); j < jmax; j++) {
 406     Node* n = best->fast_out(j);
 407     if( n->is_MachProj() ) {
 408       get_block_for_node(n)->find_remove(n);
 409       block->add_inst(n);
 410       map_node_to_block(n, block);
 411     }
 412   }
 413 
 414   // proj==Op_True --> ne test; proj==Op_False --> eq test.
 415   // One of two graph shapes got matched:
 416   //   (IfTrue  (If (Bool NE (CmpP ptr NULL))))
 417   //   (IfFalse (If (Bool EQ (CmpP ptr NULL))))
 418   // NULL checks are always branch-if-eq.  If we see a IfTrue projection
 419   // then we are replacing a 'ne' test with a 'eq' NULL check test.
 420   // We need to flip the projections to keep the same semantics.
 421   if( proj->Opcode() == Op_IfTrue ) {
 422     // Swap order of projections in basic block to swap branch targets
 423     Node *tmp1 = block->get_node(block->end_idx()+1);
 424     Node *tmp2 = block->get_node(block->end_idx()+2);
 425     block->map_node(tmp2, block->end_idx()+1);
 426     block->map_node(tmp1, block->end_idx()+2);
 427     Node *tmp = new (C) Node(C->top()); // Use not NULL input
 428     tmp1->replace_by(tmp);
 429     tmp2->replace_by(tmp1);
 430     tmp->replace_by(tmp2);
 431     tmp->destruct();
 432   }
 433 
 434   // Remove the existing null check; use a new implicit null check instead.
 435   // Since schedule-local needs precise def-use info, we need to correct
 436   // it as well.
 437   Node *old_tst = proj->in(0);
 438   MachNode *nul_chk = new (C) MachNullCheckNode(old_tst->in(0),best,bidx);
 439   block->map_node(nul_chk, block->end_idx());
 440   map_node_to_block(nul_chk, block);
 441   // Redirect users of old_test to nul_chk
 442   for (DUIterator_Last i2min, i2 = old_tst->last_outs(i2min); i2 >= i2min; --i2)
 443     old_tst->last_out(i2)->set_req(0, nul_chk);
 444   // Clean-up any dead code
 445   for (uint i3 = 0; i3 < old_tst->req(); i3++) {
 446     Node* in = old_tst->in(i3);
 447     old_tst->set_req(i3, NULL);
 448     if (in->outcnt() == 0) {
 449       // Remove dead input node
 450       in->disconnect_inputs(NULL, C);
 451       block->find_remove(in);
 452     }
 453   }
 454 
 455   latency_from_uses(nul_chk);
 456   latency_from_uses(best);
 457 
 458   // insert anti-dependences to defs in this block
 459   if (! best->needs_anti_dependence_check()) {
 460     for (uint k = 1; k < block->number_of_nodes(); k++) {
 461       Node *n = block->get_node(k);
 462       if (n->needs_anti_dependence_check() &&
 463           n->in(LoadNode::Memory) == best->in(StoreNode::Memory)) {
 464         // Found anti-dependent load
 465         insert_anti_dependences(block, n);
 466 }
 467     }
 468   }
 469 }
 470 
 471 
 472 //------------------------------select-----------------------------------------
 473 // Select a nice fellow from the worklist to schedule next. If there is only
 474 // one choice, then use it. Projections take top priority for correctness
 475 // reasons - if I see a projection, then it is next.  There are a number of
 476 // other special cases, for instructions that consume condition codes, et al.
 477 // These are chosen immediately. Some instructions are required to immediately
 478 // precede the last instruction in the block, and these are taken last. Of the
 479 // remaining cases (most), choose the instruction with the greatest latency
 480 // (that is, the most number of pseudo-cycles required to the end of the
 481 // routine). If there is a tie, choose the instruction with the most inputs.
 482 Node* PhaseCFG::select(Block* block, Node_List &worklist, GrowableArray<int> &ready_cnt, VectorSet &next_call, uint sched_slot) {
 483 
 484   // If only a single entry on the stack, use it
 485   uint cnt = worklist.size();
 486   if (cnt == 1) {
 487     Node *n = worklist[0];
 488     worklist.map(0,worklist.pop());
 489     return n;
 490   }
 491 
 492   uint choice  = 0; // Bigger is most important
 493   uint latency = 0; // Bigger is scheduled first
 494   uint score   = 0; // Bigger is better
 495   int idx = -1;     // Index in worklist
 496   int cand_cnt = 0; // Candidate count
 497 
 498   for( uint i=0; i<cnt; i++ ) { // Inspect entire worklist
 499     // Order in worklist is used to break ties.
 500     // See caller for how this is used to delay scheduling
 501     // of induction variable increments to after the other
 502     // uses of the phi are scheduled.
 503     Node *n = worklist[i];      // Get Node on worklist
 504 
 505     int iop = n->is_Mach() ? n->as_Mach()->ideal_Opcode() : 0;
 506     if( n->is_Proj() ||         // Projections always win
 507         n->Opcode()== Op_Con || // So does constant 'Top'
 508         iop == Op_CreateEx ||   // Create-exception must start block
 509         iop == Op_CheckCastPP
 510         ) {
 511       worklist.map(i,worklist.pop());
 512       return n;
 513     }
 514 
 515     // Final call in a block must be adjacent to 'catch'
 516     Node *e = block->end();
 517     if( e->is_Catch() && e->in(0)->in(0) == n )
 518       continue;
 519 
 520     // Memory op for an implicit null check has to be at the end of the block
 521     if( e->is_MachNullCheck() && e->in(1) == n )
 522       continue;
 523 
 524     // Schedule IV increment last.
 525     if (e->is_Mach() && e->as_Mach()->ideal_Opcode() == Op_CountedLoopEnd &&
 526         e->in(1)->in(1) == n && n->is_iteratively_computed())
 527       continue;
 528 
 529     uint n_choice  = 2;
 530 
 531     // See if this instruction is consumed by a branch. If so, then (as the
 532     // branch is the last instruction in the basic block) force it to the
 533     // end of the basic block
 534     if ( must_clone[iop] ) {
 535       // See if any use is a branch
 536       bool found_machif = false;
 537 
 538       for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
 539         Node* use = n->fast_out(j);
 540 
 541         // The use is a conditional branch, make them adjacent
 542         if (use->is_MachIf() && get_block_for_node(use) == block) {
 543           found_machif = true;
 544           break;
 545         }
 546 
 547         // More than this instruction pending for successor to be ready,
 548         // don't choose this if other opportunities are ready
 549         if (ready_cnt.at(use->_idx) > 1)
 550           n_choice = 1;
 551       }
 552 
 553       // loop terminated, prefer not to use this instruction
 554       if (found_machif)
 555         continue;
 556     }
 557 
 558     // See if this has a predecessor that is "must_clone", i.e. sets the
 559     // condition code. If so, choose this first
 560     for (uint j = 0; j < n->req() ; j++) {
 561       Node *inn = n->in(j);
 562       if (inn) {
 563         if (inn->is_Mach() && must_clone[inn->as_Mach()->ideal_Opcode()] ) {
 564           n_choice = 3;
 565           break;
 566         }
 567       }
 568     }
 569 
 570     // MachTemps should be scheduled last so they are near their uses
 571     if (n->is_MachTemp()) {
 572       n_choice = 1;
 573     }
 574 
 575     uint n_latency = get_latency_for_node(n);
 576     uint n_score   = n->req();   // Many inputs get high score to break ties
 577 
 578     // Keep best latency found
 579     cand_cnt++;
 580     if (choice < n_choice ||
 581         (choice == n_choice &&
 582          ((StressLCM && Compile::randomized_select(cand_cnt)) ||
 583           (!StressLCM &&
 584            (latency < n_latency ||
 585             (latency == n_latency &&
 586              (score < n_score))))))) {
 587       choice  = n_choice;
 588       latency = n_latency;
 589       score   = n_score;
 590       idx     = i;               // Also keep index in worklist
 591     }
 592   } // End of for all ready nodes in worklist
 593 
 594   assert(idx >= 0, "index should be set");
 595   Node *n = worklist[(uint)idx];      // Get the winner
 596 
 597   worklist.map((uint)idx, worklist.pop());     // Compress worklist
 598   return n;
 599 }
 600 
 601 
 602 //------------------------------set_next_call----------------------------------
 603 void PhaseCFG::set_next_call(Block* block, Node* n, VectorSet& next_call) {
 604   if( next_call.test_set(n->_idx) ) return;
 605   for( uint i=0; i<n->len(); i++ ) {
 606     Node *m = n->in(i);
 607     if( !m ) continue;  // must see all nodes in block that precede call
 608     if (get_block_for_node(m) == block) {
 609       set_next_call(block, m, next_call);
 610     }
 611   }
 612 }
 613 
 614 //------------------------------needed_for_next_call---------------------------
 615 // Set the flag 'next_call' for each Node that is needed for the next call to
 616 // be scheduled.  This flag lets me bias scheduling so Nodes needed for the
 617 // next subroutine call get priority - basically it moves things NOT needed
 618 // for the next call till after the call.  This prevents me from trying to
 619 // carry lots of stuff live across a call.
 620 void PhaseCFG::needed_for_next_call(Block* block, Node* this_call, VectorSet& next_call) {
 621   // Find the next control-defining Node in this block
 622   Node* call = NULL;
 623   for (DUIterator_Fast imax, i = this_call->fast_outs(imax); i < imax; i++) {
 624     Node* m = this_call->fast_out(i);
 625     if (get_block_for_node(m) == block && // Local-block user
 626         m != this_call &&       // Not self-start node
 627         m->is_MachCall()) {
 628       call = m;
 629       break;
 630     }
 631   }
 632   if (call == NULL)  return;    // No next call (e.g., block end is near)
 633   // Set next-call for all inputs to this call
 634   set_next_call(block, call, next_call);
 635 }
 636 
 637 //------------------------------add_call_kills-------------------------------------
 638 // helper function that adds caller save registers to MachProjNode
 639 static void add_call_kills(MachProjNode *proj, RegMask& regs, const char* save_policy, bool exclude_soe) {
 640   // Fill in the kill mask for the call
 641   for( OptoReg::Name r = OptoReg::Name(0); r < _last_Mach_Reg; r=OptoReg::add(r,1) ) {
 642     if( !regs.Member(r) ) {     // Not already defined by the call
 643       // Save-on-call register?
 644       if ((save_policy[r] == 'C') ||
 645           (save_policy[r] == 'A') ||
 646           ((save_policy[r] == 'E') && exclude_soe)) {
 647         proj->_rout.Insert(r);
 648       }
 649     }
 650   }
 651 }
 652 
 653 
 654 //------------------------------sched_call-------------------------------------
 655 uint PhaseCFG::sched_call(Block* block, uint node_cnt, Node_List& worklist, GrowableArray<int>& ready_cnt, MachCallNode* mcall, VectorSet& next_call) {
 656   RegMask regs;
 657 
 658   // Schedule all the users of the call right now.  All the users are
 659   // projection Nodes, so they must be scheduled next to the call.
 660   // Collect all the defined registers.
 661   for (DUIterator_Fast imax, i = mcall->fast_outs(imax); i < imax; i++) {
 662     Node* n = mcall->fast_out(i);
 663     assert( n->is_MachProj(), "" );
 664     int n_cnt = ready_cnt.at(n->_idx)-1;
 665     ready_cnt.at_put(n->_idx, n_cnt);
 666     assert( n_cnt == 0, "" );
 667     // Schedule next to call
 668     block->map_node(n, node_cnt++);
 669     // Collect defined registers
 670     regs.OR(n->out_RegMask());
 671     // Check for scheduling the next control-definer
 672     if( n->bottom_type() == Type::CONTROL )
 673       // Warm up next pile of heuristic bits
 674       needed_for_next_call(block, n, next_call);
 675 
 676     // Children of projections are now all ready
 677     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
 678       Node* m = n->fast_out(j); // Get user
 679       if(get_block_for_node(m) != block) {
 680         continue;
 681       }
 682       if( m->is_Phi() ) continue;
 683       int m_cnt = ready_cnt.at(m->_idx)-1;
 684       ready_cnt.at_put(m->_idx, m_cnt);
 685       if( m_cnt == 0 )
 686         worklist.push(m);
 687     }
 688 
 689   }
 690 
 691   // Act as if the call defines the Frame Pointer.
 692   // Certainly the FP is alive and well after the call.
 693   regs.Insert(_matcher.c_frame_pointer());
 694 
 695   // Set all registers killed and not already defined by the call.
 696   uint r_cnt = mcall->tf()->range()->cnt();
 697   int op = mcall->ideal_Opcode();
 698   MachProjNode *proj = new (C) MachProjNode( mcall, r_cnt+1, RegMask::Empty, MachProjNode::fat_proj );
 699   map_node_to_block(proj, block);
 700   block->insert_node(proj, node_cnt++);
 701 
 702   // Select the right register save policy.
 703   const char *save_policy = NULL;
 704   switch (op) {
 705     case Op_CallRuntime:
 706     case Op_CallLeaf:
 707     case Op_CallLeafNoFP:
 708       // Calling C code so use C calling convention
 709       save_policy = _matcher._c_reg_save_policy;
 710       break;
 711 
 712     case Op_CallStaticJava:
 713     case Op_CallDynamicJava:
 714       // Calling Java code so use Java calling convention
 715       save_policy = _matcher._register_save_policy;
 716       break;
 717 
 718     default:
 719       ShouldNotReachHere();
 720   }
 721 
 722   // When using CallRuntime mark SOE registers as killed by the call
 723   // so values that could show up in the RegisterMap aren't live in a
 724   // callee saved register since the register wouldn't know where to
 725   // find them.  CallLeaf and CallLeafNoFP are ok because they can't
 726   // have debug info on them.  Strictly speaking this only needs to be
 727   // done for oops since idealreg2debugmask takes care of debug info
 728   // references but there no way to handle oops differently than other
 729   // pointers as far as the kill mask goes.
 730   bool exclude_soe = op == Op_CallRuntime;
 731 
 732   // If the call is a MethodHandle invoke, we need to exclude the
 733   // register which is used to save the SP value over MH invokes from
 734   // the mask.  Otherwise this register could be used for
 735   // deoptimization information.
 736   if (op == Op_CallStaticJava) {
 737     MachCallStaticJavaNode* mcallstaticjava = (MachCallStaticJavaNode*) mcall;
 738     if (mcallstaticjava->_method_handle_invoke)
 739       proj->_rout.OR(Matcher::method_handle_invoke_SP_save_mask());
 740   }
 741 
 742   add_call_kills(proj, regs, save_policy, exclude_soe);
 743 
 744   return node_cnt;
 745 }
 746 
 747 
 748 //------------------------------schedule_local---------------------------------
 749 // Topological sort within a block.  Someday become a real scheduler.
 750 bool PhaseCFG::schedule_local(Block* block, GrowableArray<int>& ready_cnt, VectorSet& next_call) {
 751   // Already "sorted" are the block start Node (as the first entry), and
 752   // the block-ending Node and any trailing control projections.  We leave
 753   // these alone.  PhiNodes and ParmNodes are made to follow the block start
 754   // Node.  Everything else gets topo-sorted.
 755 
 756 #ifndef PRODUCT
 757     if (trace_opto_pipelining()) {
 758       tty->print_cr("# --- schedule_local B%d, before: ---", block->_pre_order);
 759       for (uint i = 0;i < block->number_of_nodes(); i++) {
 760         tty->print("# ");
 761         block->get_node(i)->fast_dump();
 762       }
 763       tty->print_cr("#");
 764     }
 765 #endif
 766 
 767   // RootNode is already sorted
 768   if (block->number_of_nodes() == 1) {
 769     return true;
 770   }
 771 
 772   // Move PhiNodes and ParmNodes from 1 to cnt up to the start
 773   uint node_cnt = block->end_idx();
 774   uint phi_cnt = 1;
 775   uint i;
 776   for( i = 1; i<node_cnt; i++ ) { // Scan for Phi
 777     Node *n = block->get_node(i);
 778     if( n->is_Phi() ||          // Found a PhiNode or ParmNode
 779         (n->is_Proj()  && n->in(0) == block->head()) ) {
 780       // Move guy at 'phi_cnt' to the end; makes a hole at phi_cnt
 781       block->map_node(block->get_node(phi_cnt), i);
 782       block->map_node(n, phi_cnt++);  // swap Phi/Parm up front
 783     } else {                    // All others
 784       // Count block-local inputs to 'n'
 785       uint cnt = n->len();      // Input count
 786       uint local = 0;
 787       for( uint j=0; j<cnt; j++ ) {
 788         Node *m = n->in(j);
 789         if( m && get_block_for_node(m) == block && !m->is_top() )
 790           local++;              // One more block-local input
 791       }
 792       ready_cnt.at_put(n->_idx, local); // Count em up
 793 
 794 #ifdef ASSERT
 795       if( UseConcMarkSweepGC || UseG1GC ) {
 796         if( n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_StoreCM ) {
 797           // Check the precedence edges
 798           for (uint prec = n->req(); prec < n->len(); prec++) {
 799             Node* oop_store = n->in(prec);
 800             if (oop_store != NULL) {
 801               assert(get_block_for_node(oop_store)->_dom_depth <= block->_dom_depth, "oop_store must dominate card-mark");
 802             }
 803           }
 804         }
 805       }
 806 #endif
 807 
 808       // A few node types require changing a required edge to a precedence edge
 809       // before allocation.
 810       if( n->is_Mach() && n->req() > TypeFunc::Parms &&
 811           (n->as_Mach()->ideal_Opcode() == Op_MemBarAcquire ||
 812            n->as_Mach()->ideal_Opcode() == Op_MemBarVolatile) ) {
 813         // MemBarAcquire could be created without Precedent edge.
 814         // del_req() replaces the specified edge with the last input edge
 815         // and then removes the last edge. If the specified edge > number of
 816         // edges the last edge will be moved outside of the input edges array
 817         // and the edge will be lost. This is why this code should be
 818         // executed only when Precedent (== TypeFunc::Parms) edge is present.
 819         Node *x = n->in(TypeFunc::Parms);
 820         n->del_req(TypeFunc::Parms);
 821         n->add_prec(x);
 822       }
 823     }
 824   }
 825   for(uint i2=i; i2< block->number_of_nodes(); i2++ ) // Trailing guys get zapped count
 826     ready_cnt.at_put(block->get_node(i2)->_idx, 0);
 827 
 828   // All the prescheduled guys do not hold back internal nodes
 829   uint i3;
 830   for(i3 = 0; i3<phi_cnt; i3++ ) {  // For all pre-scheduled
 831     Node *n = block->get_node(i3);       // Get pre-scheduled
 832     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
 833       Node* m = n->fast_out(j);
 834       if (get_block_for_node(m) == block) { // Local-block user
 835         int m_cnt = ready_cnt.at(m->_idx)-1;
 836         ready_cnt.at_put(m->_idx, m_cnt);   // Fix ready count
 837       }
 838     }
 839   }
 840 
 841   Node_List delay;
 842   // Make a worklist
 843   Node_List worklist;
 844   for(uint i4=i3; i4<node_cnt; i4++ ) {    // Put ready guys on worklist
 845     Node *m = block->get_node(i4);
 846     if( !ready_cnt.at(m->_idx) ) {   // Zero ready count?
 847       if (m->is_iteratively_computed()) {
 848         // Push induction variable increments last to allow other uses
 849         // of the phi to be scheduled first. The select() method breaks
 850         // ties in scheduling by worklist order.
 851         delay.push(m);
 852       } else if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_CreateEx) {
 853         // Force the CreateEx to the top of the list so it's processed
 854         // first and ends up at the start of the block.
 855         worklist.insert(0, m);
 856       } else {
 857         worklist.push(m);         // Then on to worklist!
 858       }
 859     }
 860   }
 861   while (delay.size()) {
 862     Node* d = delay.pop();
 863     worklist.push(d);
 864   }
 865 
 866   // Warm up the 'next_call' heuristic bits
 867   needed_for_next_call(block, block->head(), next_call);
 868 
 869 #ifndef PRODUCT
 870     if (trace_opto_pipelining()) {
 871       for (uint j=0; j< block->number_of_nodes(); j++) {
 872         Node     *n = block->get_node(j);
 873         int     idx = n->_idx;
 874         tty->print("#   ready cnt:%3d  ", ready_cnt.at(idx));
 875         tty->print("latency:%3d  ", get_latency_for_node(n));
 876         tty->print("%4d: %s\n", idx, n->Name());
 877       }
 878     }
 879 #endif
 880 
 881   uint max_idx = (uint)ready_cnt.length();
 882   // Pull from worklist and schedule
 883   while( worklist.size() ) {    // Worklist is not ready
 884 
 885 #ifndef PRODUCT
 886     if (trace_opto_pipelining()) {
 887       tty->print("#   ready list:");
 888       for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
 889         Node *n = worklist[i];      // Get Node on worklist
 890         tty->print(" %d", n->_idx);
 891       }
 892       tty->cr();
 893     }
 894 #endif
 895 
 896     // Select and pop a ready guy from worklist
 897     Node* n = select(block, worklist, ready_cnt, next_call, phi_cnt);
 898     block->map_node(n, phi_cnt++);    // Schedule him next
 899 
 900 #ifndef PRODUCT
 901     if (trace_opto_pipelining()) {
 902       tty->print("#    select %d: %s", n->_idx, n->Name());
 903       tty->print(", latency:%d", get_latency_for_node(n));
 904       n->dump();
 905       if (Verbose) {
 906         tty->print("#   ready list:");
 907         for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
 908           Node *n = worklist[i];      // Get Node on worklist
 909           tty->print(" %d", n->_idx);
 910         }
 911         tty->cr();
 912       }
 913     }
 914 
 915 #endif
 916     if( n->is_MachCall() ) {
 917       MachCallNode *mcall = n->as_MachCall();
 918       phi_cnt = sched_call(block, phi_cnt, worklist, ready_cnt, mcall, next_call);
 919       continue;
 920     }
 921 
 922     if (n->is_Mach() && n->as_Mach()->has_call()) {
 923       RegMask regs;
 924       regs.Insert(_matcher.c_frame_pointer());
 925       regs.OR(n->out_RegMask());
 926 
 927       MachProjNode *proj = new (C) MachProjNode( n, 1, RegMask::Empty, MachProjNode::fat_proj );
 928       map_node_to_block(proj, block);
 929       block->insert_node(proj, phi_cnt++);
 930 
 931       add_call_kills(proj, regs, _matcher._c_reg_save_policy, false);
 932     }
 933 
 934     // Children are now all ready
 935     for (DUIterator_Fast i5max, i5 = n->fast_outs(i5max); i5 < i5max; i5++) {
 936       Node* m = n->fast_out(i5); // Get user
 937       if (get_block_for_node(m) != block) {
 938         continue;
 939       }
 940       if( m->is_Phi() ) continue;
 941       if (m->_idx >= max_idx) { // new node, skip it
 942         assert(m->is_MachProj() && n->is_Mach() && n->as_Mach()->has_call(), "unexpected node types");
 943         continue;
 944       }
 945       int m_cnt = ready_cnt.at(m->_idx)-1;
 946       ready_cnt.at_put(m->_idx, m_cnt);
 947       if( m_cnt == 0 )
 948         worklist.push(m);
 949     }
 950   }
 951 
 952   if( phi_cnt != block->end_idx() ) {
 953     // did not schedule all.  Retry, Bailout, or Die
 954     if (C->subsume_loads() == true && !C->failing()) {
 955       // Retry with subsume_loads == false
 956       // If this is the first failure, the sentinel string will "stick"
 957       // to the Compile object, and the C2Compiler will see it and retry.
 958       C->record_failure(C2Compiler::retry_no_subsuming_loads());
 959     }
 960     // assert( phi_cnt == end_idx(), "did not schedule all" );
 961     return false;
 962   }
 963 
 964 #ifndef PRODUCT
 965   if (trace_opto_pipelining()) {
 966     tty->print_cr("#");
 967     tty->print_cr("# after schedule_local");
 968     for (uint i = 0;i < block->number_of_nodes();i++) {
 969       tty->print("# ");
 970       block->get_node(i)->fast_dump();
 971     }
 972     tty->cr();
 973   }
 974 #endif
 975 
 976 
 977   return true;
 978 }
 979 
 980 //--------------------------catch_cleanup_fix_all_inputs-----------------------
 981 static void catch_cleanup_fix_all_inputs(Node *use, Node *old_def, Node *new_def) {
 982   for (uint l = 0; l < use->len(); l++) {
 983     if (use->in(l) == old_def) {
 984       if (l < use->req()) {
 985         use->set_req(l, new_def);
 986       } else {
 987         use->rm_prec(l);
 988         use->add_prec(new_def);
 989         l--;
 990       }
 991     }
 992   }
 993 }
 994 
 995 //------------------------------catch_cleanup_find_cloned_def------------------
 996 Node* PhaseCFG::catch_cleanup_find_cloned_def(Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) {
 997   assert( use_blk != def_blk, "Inter-block cleanup only");
 998 
 999   // The use is some block below the Catch.  Find and return the clone of the def
1000   // that dominates the use. If there is no clone in a dominating block, then
1001   // create a phi for the def in a dominating block.
1002 
1003   // Find which successor block dominates this use.  The successor
1004   // blocks must all be single-entry (from the Catch only; I will have
1005   // split blocks to make this so), hence they all dominate.
1006   while( use_blk->_dom_depth > def_blk->_dom_depth+1 )
1007     use_blk = use_blk->_idom;
1008 
1009   // Find the successor
1010   Node *fixup = NULL;
1011 
1012   uint j;
1013   for( j = 0; j < def_blk->_num_succs; j++ )
1014     if( use_blk == def_blk->_succs[j] )
1015       break;
1016 
1017   if( j == def_blk->_num_succs ) {
1018     // Block at same level in dom-tree is not a successor.  It needs a
1019     // PhiNode, the PhiNode uses from the def and IT's uses need fixup.
1020     Node_Array inputs = new Node_List(Thread::current()->resource_area());
1021     for(uint k = 1; k < use_blk->num_preds(); k++) {
1022       Block* block = get_block_for_node(use_blk->pred(k));
1023       inputs.map(k, catch_cleanup_find_cloned_def(block, def, def_blk, n_clone_idx));
1024     }
1025 
1026     // Check to see if the use_blk already has an identical phi inserted.
1027     // If it exists, it will be at the first position since all uses of a
1028     // def are processed together.
1029     Node *phi = use_blk->get_node(1);
1030     if( phi->is_Phi() ) {
1031       fixup = phi;
1032       for (uint k = 1; k < use_blk->num_preds(); k++) {
1033         if (phi->in(k) != inputs[k]) {
1034           // Not a match
1035           fixup = NULL;
1036           break;
1037         }
1038       }
1039     }
1040 
1041     // If an existing PhiNode was not found, make a new one.
1042     if (fixup == NULL) {
1043       Node *new_phi = PhiNode::make(use_blk->head(), def);
1044       use_blk->insert_node(new_phi, 1);
1045       map_node_to_block(new_phi, use_blk);
1046       for (uint k = 1; k < use_blk->num_preds(); k++) {
1047         new_phi->set_req(k, inputs[k]);
1048       }
1049       fixup = new_phi;
1050     }
1051 
1052   } else {
1053     // Found the use just below the Catch.  Make it use the clone.
1054     fixup = use_blk->get_node(n_clone_idx);
1055   }
1056 
1057   return fixup;
1058 }
1059 
1060 //--------------------------catch_cleanup_intra_block--------------------------
1061 // Fix all input edges in use that reference "def".  The use is in the same
1062 // block as the def and both have been cloned in each successor block.
1063 static void catch_cleanup_intra_block(Node *use, Node *def, Block *blk, int beg, int n_clone_idx) {
1064 
1065   // Both the use and def have been cloned. For each successor block,
1066   // get the clone of the use, and make its input the clone of the def
1067   // found in that block.
1068 
1069   uint use_idx = blk->find_node(use);
1070   uint offset_idx = use_idx - beg;
1071   for( uint k = 0; k < blk->_num_succs; k++ ) {
1072     // Get clone in each successor block
1073     Block *sb = blk->_succs[k];
1074     Node *clone = sb->get_node(offset_idx+1);
1075     assert( clone->Opcode() == use->Opcode(), "" );
1076 
1077     // Make use-clone reference the def-clone
1078     catch_cleanup_fix_all_inputs(clone, def, sb->get_node(n_clone_idx));
1079   }
1080 }
1081 
1082 //------------------------------catch_cleanup_inter_block---------------------
1083 // Fix all input edges in use that reference "def".  The use is in a different
1084 // block than the def.
1085 void PhaseCFG::catch_cleanup_inter_block(Node *use, Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) {
1086   if( !use_blk ) return;        // Can happen if the use is a precedence edge
1087 
1088   Node *new_def = catch_cleanup_find_cloned_def(use_blk, def, def_blk, n_clone_idx);
1089   catch_cleanup_fix_all_inputs(use, def, new_def);
1090 }
1091 
1092 //------------------------------call_catch_cleanup-----------------------------
1093 // If we inserted any instructions between a Call and his CatchNode,
1094 // clone the instructions on all paths below the Catch.
1095 void PhaseCFG::call_catch_cleanup(Block* block) {
1096 
1097   // End of region to clone
1098   uint end = block->end_idx();
1099   if( !block->get_node(end)->is_Catch() ) return;
1100   // Start of region to clone
1101   uint beg = end;
1102   while(!block->get_node(beg-1)->is_MachProj() ||
1103         !block->get_node(beg-1)->in(0)->is_MachCall() ) {
1104     beg--;
1105     assert(beg > 0,"Catch cleanup walking beyond block boundary");
1106   }
1107   // Range of inserted instructions is [beg, end)
1108   if( beg == end ) return;
1109 
1110   // Clone along all Catch output paths.  Clone area between the 'beg' and
1111   // 'end' indices.
1112   for( uint i = 0; i < block->_num_succs; i++ ) {
1113     Block *sb = block->_succs[i];
1114     // Clone the entire area; ignoring the edge fixup for now.
1115     for( uint j = end; j > beg; j-- ) {
1116       Node *clone = block->get_node(j-1)->clone();
1117       sb->insert_node(clone, 1);
1118       map_node_to_block(clone, sb);
1119       if (clone->needs_anti_dependence_check()) {
1120         insert_anti_dependences(sb, clone);
1121       }
1122     }
1123   }
1124 
1125 
1126   // Fixup edges.  Check the def-use info per cloned Node
1127   for(uint i2 = beg; i2 < end; i2++ ) {
1128     uint n_clone_idx = i2-beg+1; // Index of clone of n in each successor block
1129     Node *n = block->get_node(i2);        // Node that got cloned
1130     // Need DU safe iterator because of edge manipulation in calls.
1131     Unique_Node_List *out = new Unique_Node_List(Thread::current()->resource_area());
1132     for (DUIterator_Fast j1max, j1 = n->fast_outs(j1max); j1 < j1max; j1++) {
1133       out->push(n->fast_out(j1));
1134     }
1135     uint max = out->size();
1136     for (uint j = 0; j < max; j++) {// For all users
1137       Node *use = out->pop();
1138       Block *buse = get_block_for_node(use);
1139       if( use->is_Phi() ) {
1140         for( uint k = 1; k < use->req(); k++ )
1141           if( use->in(k) == n ) {
1142             Block* b = get_block_for_node(buse->pred(k));
1143             Node *fixup = catch_cleanup_find_cloned_def(b, n, block, n_clone_idx);
1144             use->set_req(k, fixup);
1145           }
1146       } else {
1147         if (block == buse) {
1148           catch_cleanup_intra_block(use, n, block, beg, n_clone_idx);
1149         } else {
1150           catch_cleanup_inter_block(use, buse, n, block, n_clone_idx);
1151         }
1152       }
1153     } // End for all users
1154 
1155   } // End of for all Nodes in cloned area
1156 
1157   // Remove the now-dead cloned ops
1158   for(uint i3 = beg; i3 < end; i3++ ) {
1159     block->get_node(beg)->disconnect_inputs(NULL, C);
1160     block->remove_node(beg);
1161   }
1162 
1163   // If the successor blocks have a CreateEx node, move it back to the top
1164   for(uint i4 = 0; i4 < block->_num_succs; i4++ ) {
1165     Block *sb = block->_succs[i4];
1166     uint new_cnt = end - beg;
1167     // Remove any newly created, but dead, nodes.
1168     for( uint j = new_cnt; j > 0; j-- ) {
1169       Node *n = sb->get_node(j);
1170       if (n->outcnt() == 0 &&
1171           (!n->is_Proj() || n->as_Proj()->in(0)->outcnt() == 1) ){
1172         n->disconnect_inputs(NULL, C);
1173         sb->remove_node(j);
1174         new_cnt--;
1175       }
1176     }
1177     // If any newly created nodes remain, move the CreateEx node to the top
1178     if (new_cnt > 0) {
1179       Node *cex = sb->get_node(1+new_cnt);
1180       if( cex->is_Mach() && cex->as_Mach()->ideal_Opcode() == Op_CreateEx ) {
1181         sb->remove_node(1+new_cnt);
1182         sb->insert_node(cex, 1);
1183       }
1184     }
1185   }
1186 }