src/share/vm/opto/ifg.cpp

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rev 4333 : imported patch log_file


  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 "compiler/oopMap.hpp"
  27 #include "memory/allocation.inline.hpp"
  28 #include "opto/addnode.hpp"
  29 #include "opto/block.hpp"
  30 #include "opto/callnode.hpp"
  31 #include "opto/cfgnode.hpp"
  32 #include "opto/chaitin.hpp"
  33 #include "opto/coalesce.hpp"
  34 #include "opto/connode.hpp"
  35 #include "opto/indexSet.hpp"
  36 #include "opto/machnode.hpp"
  37 #include "opto/memnode.hpp"
  38 #include "opto/opcodes.hpp"
  39 
  40 #define EXACT_PRESSURE 1
  41 
  42 //=============================================================================
  43 //------------------------------IFG--------------------------------------------
  44 PhaseIFG::PhaseIFG( Arena *arena ) : Phase(Interference_Graph), _arena(arena) {
  45 }
  46 
  47 //------------------------------init-------------------------------------------
  48 void PhaseIFG::init( uint maxlrg ) {
  49   _maxlrg = maxlrg;
  50   _yanked = new (_arena) VectorSet(_arena);
  51   _is_square = false;
  52   // Make uninitialized adjacency lists
  53   _adjs = (IndexSet*)_arena->Amalloc(sizeof(IndexSet)*maxlrg);
  54   // Also make empty live range structures
  55   _lrgs = (LRG *)_arena->Amalloc( maxlrg * sizeof(LRG) );
  56   memset(_lrgs,0,sizeof(LRG)*maxlrg);
  57   // Init all to empty
  58   for( uint i = 0; i < maxlrg; i++ ) {
  59     _adjs[i].initialize(maxlrg);
  60     _lrgs[i].Set_All();
  61   }


 428   IndexSetIterator elements(liveout);
 429   uint lidx;
 430   uint cnt = 0;
 431   while ((lidx = elements.next()) != 0) {
 432     if( lrgs(lidx).mask().is_UP() &&
 433         lrgs(lidx).mask_size() &&
 434         (lrgs(lidx)._is_float || lrgs(lidx)._is_vector))
 435       cnt += lrgs(lidx).reg_pressure();
 436   }
 437   return cnt;
 438 }
 439 
 440 //------------------------------lower_pressure---------------------------------
 441 // Adjust register pressure down by 1.  Capture last hi-to-low transition,
 442 static void lower_pressure( LRG *lrg, uint where, Block *b, uint *pressure, uint *hrp_index ) {
 443   if (lrg->mask().is_UP() && lrg->mask_size()) {
 444     if (lrg->_is_float || lrg->_is_vector) {
 445       pressure[1] -= lrg->reg_pressure();
 446       if( pressure[1] == (uint)FLOATPRESSURE ) {
 447         hrp_index[1] = where;
 448 #ifdef EXACT_PRESSURE
 449       if( pressure[1] > b->_freg_pressure )
 450         b->_freg_pressure = pressure[1]+1;
 451 #else
 452         b->_freg_pressure = (uint)FLOATPRESSURE+1;
 453 #endif
 454       }
 455     } else if( lrg->mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) {
 456       pressure[0] -= lrg->reg_pressure();
 457       if( pressure[0] == (uint)INTPRESSURE   ) {
 458         hrp_index[0] = where;
 459 #ifdef EXACT_PRESSURE
 460       if( pressure[0] > b->_reg_pressure )
 461         b->_reg_pressure = pressure[0]+1;
 462 #else
 463         b->_reg_pressure = (uint)INTPRESSURE+1;
 464 #endif
 465       }
 466     }
 467   }
 468 }
 469 
 470 //------------------------------build_ifg_physical-----------------------------
 471 // Build the interference graph using physical registers when available.
 472 // That is, if 2 live ranges are simultaneously alive but in their acceptable
 473 // register sets do not overlap, then they do not interfere.
 474 uint PhaseChaitin::build_ifg_physical( ResourceArea *a ) {
 475   NOT_PRODUCT( Compile::TracePhase t3("buildIFG", &_t_buildIFGphysical, TimeCompiler); )
 476 
 477   uint spill_reg = LRG::SPILL_REG;
 478   uint must_spill = 0;
 479 
 480   // For all blocks (in any order) do...
 481   for( uint i = 0; i < _cfg._num_blocks; i++ ) {
 482     Block *b = _cfg._blocks[i];
 483     // Clone (rather than smash in place) the liveout info, so it is alive
 484     // for the "collect_gc_info" phase later.


 509     // Reset block's register pressure values for each ifg construction
 510     uint pressure[2], hrp_index[2];
 511     pressure[0] = pressure[1] = 0;
 512     hrp_index[0] = hrp_index[1] = last_inst+1;
 513     b->_reg_pressure = b->_freg_pressure = 0;
 514     // Liveout things are presumed live for the whole block.  We accumulate
 515     // 'area' accordingly.  If they get killed in the block, we'll subtract
 516     // the unused part of the block from the area.
 517     int inst_count = last_inst - first_inst;
 518     double cost = (inst_count <= 0) ? 0.0 : b->_freq * double(inst_count);
 519     assert(!(cost < 0.0), "negative spill cost" );
 520     IndexSetIterator elements(&liveout);
 521     uint lidx;
 522     while ((lidx = elements.next()) != 0) {
 523       LRG &lrg = lrgs(lidx);
 524       lrg._area += cost;
 525       // Compute initial register pressure
 526       if (lrg.mask().is_UP() && lrg.mask_size()) {
 527         if (lrg._is_float || lrg._is_vector) {   // Count float pressure
 528           pressure[1] += lrg.reg_pressure();
 529 #ifdef EXACT_PRESSURE
 530           if( pressure[1] > b->_freg_pressure )
 531             b->_freg_pressure = pressure[1];
 532 #endif
 533           // Count int pressure, but do not count the SP, flags
 534         } else if( lrgs(lidx).mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) {
 535           pressure[0] += lrg.reg_pressure();
 536 #ifdef EXACT_PRESSURE
 537           if( pressure[0] > b->_reg_pressure )
 538             b->_reg_pressure = pressure[0];
 539 #endif
 540         }
 541       }
 542     }
 543     assert( pressure[0] == count_int_pressure  (&liveout), "" );
 544     assert( pressure[1] == count_float_pressure(&liveout), "" );
 545 
 546     // The IFG is built by a single reverse pass over each basic block.
 547     // Starting with the known live-out set, we remove things that get
 548     // defined and add things that become live (essentially executing one
 549     // pass of a standard LIVE analysis).  Just before a Node defines a value
 550     // (and removes it from the live-ness set) that value is certainly live.
 551     // The defined value interferes with everything currently live.  The
 552     // value is then removed from the live-ness set and it's inputs are added
 553     // to the live-ness set.
 554     uint j;
 555     for( j = last_inst + 1; j > 1; j-- ) {
 556       Node *n = b->_nodes[j - 1];
 557 
 558       // Get value being defined
 559       uint r = n2lidx(n);


 572               // Could also be a flags-projection of a dead ADD or such.
 573               (n2lidx(def) && !liveout.member(n2lidx(def)) ) ) {
 574             b->_nodes.remove(j - 1);
 575             if( lrgs(r)._def == n ) lrgs(r)._def = 0;
 576             n->disconnect_inputs(NULL, C);
 577             _cfg._bbs.map(n->_idx,NULL);
 578             n->replace_by(C->top());
 579             // Since yanking a Node from block, high pressure moves up one
 580             hrp_index[0]--;
 581             hrp_index[1]--;
 582             continue;
 583           }
 584 
 585           // Fat-projections kill many registers which cannot be used to
 586           // hold live ranges.
 587           if( lrgs(r)._fat_proj ) {
 588             // Count the int-only registers
 589             RegMask itmp = lrgs(r).mask();
 590             itmp.AND(*Matcher::idealreg2regmask[Op_RegI]);
 591             int iregs = itmp.Size();
 592 #ifdef EXACT_PRESSURE
 593             if( pressure[0]+iregs > b->_reg_pressure )
 594               b->_reg_pressure = pressure[0]+iregs;
 595 #endif
 596             if( pressure[0]       <= (uint)INTPRESSURE &&
 597                 pressure[0]+iregs >  (uint)INTPRESSURE ) {
 598 #ifndef EXACT_PRESSURE
 599               b->_reg_pressure = (uint)INTPRESSURE+1;
 600 #endif
 601               hrp_index[0] = j-1;
 602             }
 603             // Count the float-only registers
 604             RegMask ftmp = lrgs(r).mask();
 605             ftmp.AND(*Matcher::idealreg2regmask[Op_RegD]);
 606             int fregs = ftmp.Size();
 607 #ifdef EXACT_PRESSURE
 608             if( pressure[1]+fregs > b->_freg_pressure )
 609               b->_freg_pressure = pressure[1]+fregs;
 610 #endif
 611             if( pressure[1]       <= (uint)FLOATPRESSURE &&
 612                 pressure[1]+fregs >  (uint)FLOATPRESSURE ) {
 613 #ifndef EXACT_PRESSURE
 614               b->_freg_pressure = (uint)FLOATPRESSURE+1;
 615 #endif
 616               hrp_index[1] = j-1;
 617             }
 618           }
 619 
 620         } else {                // Else it is live
 621           // A DEF also ends 'area' partway through the block.
 622           lrgs(r)._area -= cost;
 623           assert(!(lrgs(r)._area < 0.0), "negative spill area" );
 624 
 625           // Insure high score for immediate-use spill copies so they get a color
 626           if( n->is_SpillCopy()
 627               && lrgs(r).is_singledef()        // MultiDef live range can still split
 628               && n->outcnt() == 1              // and use must be in this block
 629               && _cfg._bbs[n->unique_out()->_idx] == b ) {
 630             // All single-use MachSpillCopy(s) that immediately precede their
 631             // use must color early.  If a longer live range steals their
 632             // color, the spill copy will split and may push another spill copy
 633             // further away resulting in an infinite spill-split-retry cycle.
 634             // Assigning a zero area results in a high score() and a good
 635             // location in the simplify list.


 752         // flag-setting behavior alive while also keeping the (useful)
 753         // memory update effect.
 754         for( uint k = ((n->Opcode() == Op_SCMemProj) ? 0:1); k < n->req(); k++ ) {
 755           Node *def = n->in(k);
 756           uint x = n2lidx(def);
 757           if( !x ) continue;
 758           LRG &lrg = lrgs(x);
 759           // No use-side cost for spilling debug info
 760           if( k < debug_start )
 761             // A USE costs twice block frequency (once for the Load, once
 762             // for a Load-delay).  Rematerialized uses only cost once.
 763             lrg._cost += (def->rematerialize() ? b->_freq : (b->_freq + b->_freq));
 764           // It is live now
 765           if( liveout.insert( x ) ) {
 766             // Newly live things assumed live from here to top of block
 767             lrg._area += cost;
 768             // Adjust register pressure
 769             if (lrg.mask().is_UP() && lrg.mask_size()) {
 770               if (lrg._is_float || lrg._is_vector) {
 771                 pressure[1] += lrg.reg_pressure();
 772 #ifdef EXACT_PRESSURE
 773                 if( pressure[1] > b->_freg_pressure )
 774                   b->_freg_pressure = pressure[1];
 775 #endif
 776               } else if( lrg.mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) {
 777                 pressure[0] += lrg.reg_pressure();
 778 #ifdef EXACT_PRESSURE
 779                 if( pressure[0] > b->_reg_pressure )
 780                   b->_reg_pressure = pressure[0];
 781 #endif
 782               }
 783             }
 784             assert( pressure[0] == count_int_pressure  (&liveout), "" );
 785             assert( pressure[1] == count_float_pressure(&liveout), "" );
 786           }
 787           assert(!(lrg._area < 0.0), "negative spill area" );
 788         }
 789       }
 790     } // End of reverse pass over all instructions in block
 791 
 792     // If we run off the top of the block with high pressure and
 793     // never see a hi-to-low pressure transition, just record that
 794     // the whole block is high pressure.
 795     if( pressure[0] > (uint)INTPRESSURE   ) {
 796       hrp_index[0] = 0;
 797 #ifdef EXACT_PRESSURE
 798       if( pressure[0] > b->_reg_pressure )
 799         b->_reg_pressure = pressure[0];
 800 #else
 801       b->_reg_pressure = (uint)INTPRESSURE+1;
 802 #endif
 803     }
 804     if( pressure[1] > (uint)FLOATPRESSURE ) {
 805       hrp_index[1] = 0;
 806 #ifdef EXACT_PRESSURE
 807       if( pressure[1] > b->_freg_pressure )
 808         b->_freg_pressure = pressure[1];
 809 #else
 810       b->_freg_pressure = (uint)FLOATPRESSURE+1;
 811 #endif
 812     }
 813 
 814     // Compute high pressure indice; avoid landing in the middle of projnodes
 815     j = hrp_index[0];
 816     if( j < b->_nodes.size() && j < b->end_idx()+1 ) {
 817       Node *cur = b->_nodes[j];
 818       while( cur->is_Proj() || (cur->is_MachNullCheck()) || cur->is_Catch() ) {
 819         j--;
 820         cur = b->_nodes[j];
 821       }
 822     }
 823     b->_ihrp_index = j;
 824     j = hrp_index[1];
 825     if( j < b->_nodes.size() && j < b->end_idx()+1 ) {
 826       Node *cur = b->_nodes[j];
 827       while( cur->is_Proj() || (cur->is_MachNullCheck()) || cur->is_Catch() ) {
 828         j--;
 829         cur = b->_nodes[j];
 830       }
 831     }


  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 "compiler/oopMap.hpp"
  27 #include "memory/allocation.inline.hpp"
  28 #include "opto/addnode.hpp"
  29 #include "opto/block.hpp"
  30 #include "opto/callnode.hpp"
  31 #include "opto/cfgnode.hpp"
  32 #include "opto/chaitin.hpp"
  33 #include "opto/coalesce.hpp"
  34 #include "opto/connode.hpp"
  35 #include "opto/indexSet.hpp"
  36 #include "opto/machnode.hpp"
  37 #include "opto/memnode.hpp"
  38 #include "opto/opcodes.hpp"
  39 


  40 //=============================================================================
  41 //------------------------------IFG--------------------------------------------
  42 PhaseIFG::PhaseIFG( Arena *arena ) : Phase(Interference_Graph), _arena(arena) {
  43 }
  44 
  45 //------------------------------init-------------------------------------------
  46 void PhaseIFG::init( uint maxlrg ) {
  47   _maxlrg = maxlrg;
  48   _yanked = new (_arena) VectorSet(_arena);
  49   _is_square = false;
  50   // Make uninitialized adjacency lists
  51   _adjs = (IndexSet*)_arena->Amalloc(sizeof(IndexSet)*maxlrg);
  52   // Also make empty live range structures
  53   _lrgs = (LRG *)_arena->Amalloc( maxlrg * sizeof(LRG) );
  54   memset(_lrgs,0,sizeof(LRG)*maxlrg);
  55   // Init all to empty
  56   for( uint i = 0; i < maxlrg; i++ ) {
  57     _adjs[i].initialize(maxlrg);
  58     _lrgs[i].Set_All();
  59   }


 426   IndexSetIterator elements(liveout);
 427   uint lidx;
 428   uint cnt = 0;
 429   while ((lidx = elements.next()) != 0) {
 430     if( lrgs(lidx).mask().is_UP() &&
 431         lrgs(lidx).mask_size() &&
 432         (lrgs(lidx)._is_float || lrgs(lidx)._is_vector))
 433       cnt += lrgs(lidx).reg_pressure();
 434   }
 435   return cnt;
 436 }
 437 
 438 //------------------------------lower_pressure---------------------------------
 439 // Adjust register pressure down by 1.  Capture last hi-to-low transition,
 440 static void lower_pressure( LRG *lrg, uint where, Block *b, uint *pressure, uint *hrp_index ) {
 441   if (lrg->mask().is_UP() && lrg->mask_size()) {
 442     if (lrg->_is_float || lrg->_is_vector) {
 443       pressure[1] -= lrg->reg_pressure();
 444       if( pressure[1] == (uint)FLOATPRESSURE ) {
 445         hrp_index[1] = where;
 446 
 447         if( pressure[1] > b->_freg_pressure )
 448           b->_freg_pressure = pressure[1]+1;



 449       }
 450     } else if( lrg->mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) {
 451       pressure[0] -= lrg->reg_pressure();
 452       if( pressure[0] == (uint)INTPRESSURE   ) {
 453         hrp_index[0] = where;
 454 
 455         if( pressure[0] > b->_reg_pressure )
 456           b->_reg_pressure = pressure[0]+1;



 457       }
 458     }
 459   }
 460 }
 461 
 462 //------------------------------build_ifg_physical-----------------------------
 463 // Build the interference graph using physical registers when available.
 464 // That is, if 2 live ranges are simultaneously alive but in their acceptable
 465 // register sets do not overlap, then they do not interfere.
 466 uint PhaseChaitin::build_ifg_physical( ResourceArea *a ) {
 467   NOT_PRODUCT( Compile::TracePhase t3("buildIFG", &_t_buildIFGphysical, TimeCompiler); )
 468 
 469   uint spill_reg = LRG::SPILL_REG;
 470   uint must_spill = 0;
 471 
 472   // For all blocks (in any order) do...
 473   for( uint i = 0; i < _cfg._num_blocks; i++ ) {
 474     Block *b = _cfg._blocks[i];
 475     // Clone (rather than smash in place) the liveout info, so it is alive
 476     // for the "collect_gc_info" phase later.


 501     // Reset block's register pressure values for each ifg construction
 502     uint pressure[2], hrp_index[2];
 503     pressure[0] = pressure[1] = 0;
 504     hrp_index[0] = hrp_index[1] = last_inst+1;
 505     b->_reg_pressure = b->_freg_pressure = 0;
 506     // Liveout things are presumed live for the whole block.  We accumulate
 507     // 'area' accordingly.  If they get killed in the block, we'll subtract
 508     // the unused part of the block from the area.
 509     int inst_count = last_inst - first_inst;
 510     double cost = (inst_count <= 0) ? 0.0 : b->_freq * double(inst_count);
 511     assert(!(cost < 0.0), "negative spill cost" );
 512     IndexSetIterator elements(&liveout);
 513     uint lidx;
 514     while ((lidx = elements.next()) != 0) {
 515       LRG &lrg = lrgs(lidx);
 516       lrg._area += cost;
 517       // Compute initial register pressure
 518       if (lrg.mask().is_UP() && lrg.mask_size()) {
 519         if (lrg._is_float || lrg._is_vector) {   // Count float pressure
 520           pressure[1] += lrg.reg_pressure();
 521 
 522           if( pressure[1] > b->_freg_pressure )
 523             b->_freg_pressure = pressure[1];
 524 
 525           // Count int pressure, but do not count the SP, flags
 526         } else if( lrgs(lidx).mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) {
 527           pressure[0] += lrg.reg_pressure();
 528 
 529           if( pressure[0] > b->_reg_pressure )
 530             b->_reg_pressure = pressure[0];
 531 
 532         }
 533       }
 534     }
 535     assert( pressure[0] == count_int_pressure  (&liveout), "" );
 536     assert( pressure[1] == count_float_pressure(&liveout), "" );
 537 
 538     // The IFG is built by a single reverse pass over each basic block.
 539     // Starting with the known live-out set, we remove things that get
 540     // defined and add things that become live (essentially executing one
 541     // pass of a standard LIVE analysis).  Just before a Node defines a value
 542     // (and removes it from the live-ness set) that value is certainly live.
 543     // The defined value interferes with everything currently live.  The
 544     // value is then removed from the live-ness set and it's inputs are added
 545     // to the live-ness set.
 546     uint j;
 547     for( j = last_inst + 1; j > 1; j-- ) {
 548       Node *n = b->_nodes[j - 1];
 549 
 550       // Get value being defined
 551       uint r = n2lidx(n);


 564               // Could also be a flags-projection of a dead ADD or such.
 565               (n2lidx(def) && !liveout.member(n2lidx(def)) ) ) {
 566             b->_nodes.remove(j - 1);
 567             if( lrgs(r)._def == n ) lrgs(r)._def = 0;
 568             n->disconnect_inputs(NULL, C);
 569             _cfg._bbs.map(n->_idx,NULL);
 570             n->replace_by(C->top());
 571             // Since yanking a Node from block, high pressure moves up one
 572             hrp_index[0]--;
 573             hrp_index[1]--;
 574             continue;
 575           }
 576 
 577           // Fat-projections kill many registers which cannot be used to
 578           // hold live ranges.
 579           if( lrgs(r)._fat_proj ) {
 580             // Count the int-only registers
 581             RegMask itmp = lrgs(r).mask();
 582             itmp.AND(*Matcher::idealreg2regmask[Op_RegI]);
 583             int iregs = itmp.Size();
 584 
 585             if( pressure[0]+iregs > b->_reg_pressure )
 586               b->_reg_pressure = pressure[0]+iregs;
 587 
 588             if( pressure[0]       <= (uint)INTPRESSURE &&
 589                 pressure[0]+iregs >  (uint)INTPRESSURE ) {



 590               hrp_index[0] = j-1;
 591             }
 592             // Count the float-only registers
 593             RegMask ftmp = lrgs(r).mask();
 594             ftmp.AND(*Matcher::idealreg2regmask[Op_RegD]);
 595             int fregs = ftmp.Size();
 596 
 597             if( pressure[1]+fregs > b->_freg_pressure )
 598               b->_freg_pressure = pressure[1]+fregs;
 599 
 600             if( pressure[1]       <= (uint)FLOATPRESSURE &&
 601                 pressure[1]+fregs >  (uint)FLOATPRESSURE ) {



 602               hrp_index[1] = j-1;
 603             }
 604           }
 605 
 606         } else {                // Else it is live
 607           // A DEF also ends 'area' partway through the block.
 608           lrgs(r)._area -= cost;
 609           assert(!(lrgs(r)._area < 0.0), "negative spill area" );
 610 
 611           // Insure high score for immediate-use spill copies so they get a color
 612           if( n->is_SpillCopy()
 613               && lrgs(r).is_singledef()        // MultiDef live range can still split
 614               && n->outcnt() == 1              // and use must be in this block
 615               && _cfg._bbs[n->unique_out()->_idx] == b ) {
 616             // All single-use MachSpillCopy(s) that immediately precede their
 617             // use must color early.  If a longer live range steals their
 618             // color, the spill copy will split and may push another spill copy
 619             // further away resulting in an infinite spill-split-retry cycle.
 620             // Assigning a zero area results in a high score() and a good
 621             // location in the simplify list.


 738         // flag-setting behavior alive while also keeping the (useful)
 739         // memory update effect.
 740         for( uint k = ((n->Opcode() == Op_SCMemProj) ? 0:1); k < n->req(); k++ ) {
 741           Node *def = n->in(k);
 742           uint x = n2lidx(def);
 743           if( !x ) continue;
 744           LRG &lrg = lrgs(x);
 745           // No use-side cost for spilling debug info
 746           if( k < debug_start )
 747             // A USE costs twice block frequency (once for the Load, once
 748             // for a Load-delay).  Rematerialized uses only cost once.
 749             lrg._cost += (def->rematerialize() ? b->_freq : (b->_freq + b->_freq));
 750           // It is live now
 751           if( liveout.insert( x ) ) {
 752             // Newly live things assumed live from here to top of block
 753             lrg._area += cost;
 754             // Adjust register pressure
 755             if (lrg.mask().is_UP() && lrg.mask_size()) {
 756               if (lrg._is_float || lrg._is_vector) {
 757                 pressure[1] += lrg.reg_pressure();
 758 
 759                 if( pressure[1] > b->_freg_pressure )
 760                   b->_freg_pressure = pressure[1];
 761 
 762               } else if( lrg.mask().overlap(*Matcher::idealreg2regmask[Op_RegI]) ) {
 763                 pressure[0] += lrg.reg_pressure();
 764 
 765                 if( pressure[0] > b->_reg_pressure )
 766                   b->_reg_pressure = pressure[0];
 767 
 768               }
 769             }
 770             assert( pressure[0] == count_int_pressure  (&liveout), "" );
 771             assert( pressure[1] == count_float_pressure(&liveout), "" );
 772           }
 773           assert(!(lrg._area < 0.0), "negative spill area" );
 774         }
 775       }
 776     } // End of reverse pass over all instructions in block
 777 
 778     // If we run off the top of the block with high pressure and
 779     // never see a hi-to-low pressure transition, just record that
 780     // the whole block is high pressure.
 781     if( pressure[0] > (uint)INTPRESSURE   ) {
 782       hrp_index[0] = 0;
 783 
 784       if( pressure[0] > b->_reg_pressure )
 785         b->_reg_pressure = pressure[0];



 786     }
 787     if( pressure[1] > (uint)FLOATPRESSURE ) {
 788       hrp_index[1] = 0;
 789 
 790       if( pressure[1] > b->_freg_pressure )
 791         b->_freg_pressure = pressure[1];



 792     }
 793 
 794     // Compute high pressure indice; avoid landing in the middle of projnodes
 795     j = hrp_index[0];
 796     if( j < b->_nodes.size() && j < b->end_idx()+1 ) {
 797       Node *cur = b->_nodes[j];
 798       while( cur->is_Proj() || (cur->is_MachNullCheck()) || cur->is_Catch() ) {
 799         j--;
 800         cur = b->_nodes[j];
 801       }
 802     }
 803     b->_ihrp_index = j;
 804     j = hrp_index[1];
 805     if( j < b->_nodes.size() && j < b->end_idx()+1 ) {
 806       Node *cur = b->_nodes[j];
 807       while( cur->is_Proj() || (cur->is_MachNullCheck()) || cur->is_Catch() ) {
 808         j--;
 809         cur = b->_nodes[j];
 810       }
 811     }