jdk8-mips64-public/hotspot: src/share/vm/opto/chaitin.cpp@ef57c43512d6 (annotated)

src/share/vm/opto/chaitin.cpp@ef57c43512d6 (annotated)

src/share/vm/opto/chaitin.cpp

Thu, 13 Jun 2013 22:02:40 -0700

author: ccheung
date: Thu, 13 Jun 2013 22:02:40 -0700
changeset 5259: ef57c43512d6
parent 4949: 8373c19be854
child 5285: 693e4d04fd09
permissions: -rw-r--r--

8014431: cleanup warnings indicated by the -Wunused-value compiler option on linux
Reviewed-by: dholmes, coleenp
Contributed-by: jeremymanson@google.com, calvin.cheung@oracle.com

 /*
  * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "compiler/compileLog.hpp"
 #include "compiler/oopMap.hpp"
 #include "memory/allocation.inline.hpp"
 #include "opto/addnode.hpp"
 #include "opto/block.hpp"
 #include "opto/callnode.hpp"
 #include "opto/cfgnode.hpp"
 #include "opto/chaitin.hpp"
 #include "opto/coalesce.hpp"
 #include "opto/connode.hpp"
 #include "opto/idealGraphPrinter.hpp"
 #include "opto/indexSet.hpp"
 #include "opto/machnode.hpp"
 #include "opto/memnode.hpp"
 #include "opto/opcodes.hpp"
 #include "opto/rootnode.hpp"
 //=============================================================================
 #ifndef PRODUCT
 void LRG::dump( ) const {
   ttyLocker ttyl;
   tty->print("%d ",num_regs());
   _mask.dump();
   if( _msize_valid ) {
     if( mask_size() == compute_mask_size() ) tty->print(", #%d ",_mask_size);
     else tty->print(", #!!!_%d_vs_%d ",_mask_size,_mask.Size());
   } else {
     tty->print(", #?(%d) ",_mask.Size());
   }
   tty->print("EffDeg: ");
   if( _degree_valid ) tty->print( "%d ", _eff_degree );
   else tty->print("? ");
   if( is_multidef() ) {
     tty->print("MultiDef ");
     if (_defs != NULL) {
       tty->print("(");
       for (int i = 0; i < _defs->length(); i++) {
         tty->print("N%d ", _defs->at(i)->_idx);
       }
       tty->print(") ");
     }
   }
   else if( _def == 0 ) tty->print("Dead ");
   else tty->print("Def: N%d ",_def->_idx);
   tty->print("Cost:%4.2g Area:%4.2g Score:%4.2g ",_cost,_area, score());
   // Flags
   if( _is_oop ) tty->print("Oop ");
   if( _is_float ) tty->print("Float ");
   if( _is_vector ) tty->print("Vector ");
   if( _was_spilled1 ) tty->print("Spilled ");
   if( _was_spilled2 ) tty->print("Spilled2 ");
   if( _direct_conflict ) tty->print("Direct_conflict ");
   if( _fat_proj ) tty->print("Fat ");
   if( _was_lo ) tty->print("Lo ");
   if( _has_copy ) tty->print("Copy ");
   if( _at_risk ) tty->print("Risk ");
   if( _must_spill ) tty->print("Must_spill ");
   if( _is_bound ) tty->print("Bound ");
   if( _msize_valid ) {
     if( _degree_valid && lo_degree() ) tty->print("Trivial ");
   }
   tty->cr();
 }
 #endif
 //------------------------------score------------------------------------------
 // Compute score from cost and area.  Low score is best to spill.
 static double raw_score( double cost, double area ) {
   return cost - (area*RegisterCostAreaRatio) * 1.52588e-5;
 }
 double LRG::score() const {
   // Scale _area by RegisterCostAreaRatio/64K then subtract from cost.
   // Bigger area lowers score, encourages spilling this live range.
   // Bigger cost raise score, prevents spilling this live range.
   // (Note: 1/65536 is the magic constant below; I dont trust the C optimizer
   // to turn a divide by a constant into a multiply by the reciprical).
   double score = raw_score( _cost, _area);
   // Account for area.  Basically, LRGs covering large areas are better
   // to spill because more other LRGs get freed up.
   if( _area == 0.0 )            // No area?  Then no progress to spill
     return 1e35;
   if( _was_spilled2 )           // If spilled once before, we are unlikely
     return score + 1e30;        // to make progress again.
   if( _cost >= _area*3.0 )      // Tiny area relative to cost
     return score + 1e17;        // Probably no progress to spill
   if( (_cost+_cost) >= _area*3.0 ) // Small area relative to cost
     return score + 1e10;        // Likely no progress to spill
   return score;
 }
 //------------------------------LRG_List---------------------------------------
 LRG_List::LRG_List( uint max ) : _cnt(max), _max(max), _lidxs(NEW_RESOURCE_ARRAY(uint,max)) {
   memset( _lidxs, 0, sizeof(uint)*max );
 }
 void LRG_List::extend( uint nidx, uint lidx ) {
   _nesting.check();
   if( nidx >= _max ) {
     uint size = 16;
     while( size <= nidx ) size <<=1;
     _lidxs = REALLOC_RESOURCE_ARRAY( uint, _lidxs, _max, size );
     _max = size;
   }
   while( _cnt <= nidx )
     _lidxs[_cnt++] = 0;
   _lidxs[nidx] = lidx;
 }
 #define NUMBUCKS 3
 // Straight out of Tarjan's union-find algorithm
 uint LiveRangeMap::find_compress(uint lrg) {
   uint cur = lrg;
   uint next = _uf_map[cur];
   while (next != cur) { // Scan chain of equivalences
     assert( next < cur, "always union smaller");
     cur = next; // until find a fixed-point
     next = _uf_map[cur];
   }
   // Core of union-find algorithm: update chain of
   // equivalences to be equal to the root.
   while (lrg != next) {
     uint tmp = _uf_map[lrg];
     _uf_map.map(lrg, next);
     lrg = tmp;
   }
   return lrg;
 }
 // Reset the Union-Find map to identity
 void LiveRangeMap::reset_uf_map(uint max_lrg_id) {
   _max_lrg_id= max_lrg_id;
   // Force the Union-Find mapping to be at least this large
   _uf_map.extend(_max_lrg_id, 0);
   // Initialize it to be the ID mapping.
   for (uint i = 0; i < _max_lrg_id; ++i) {
     _uf_map.map(i, i);
   }
 }
 // Make all Nodes map directly to their final live range; no need for
 // the Union-Find mapping after this call.
 void LiveRangeMap::compress_uf_map_for_nodes() {
   // For all Nodes, compress mapping
   uint unique = _names.Size();
   for (uint i = 0; i < unique; ++i) {
     uint lrg = _names[i];
     uint compressed_lrg = find(lrg);
     if (lrg != compressed_lrg) {
       _names.map(i, compressed_lrg);
     }
   }
 }
 // Like Find above, but no path compress, so bad asymptotic behavior
 uint LiveRangeMap::find_const(uint lrg) const {
   if (!lrg) {
     return lrg; // Ignore the zero LRG
   }
   // Off the end?  This happens during debugging dumps when you got
   // brand new live ranges but have not told the allocator yet.
   if (lrg >= _max_lrg_id) {
     return lrg;
   }
   uint next = _uf_map[lrg];
   while (next != lrg) { // Scan chain of equivalences
     assert(next < lrg, "always union smaller");
     lrg = next; // until find a fixed-point
     next = _uf_map[lrg];
   }
   return next;
 }
 //------------------------------Chaitin----------------------------------------
 PhaseChaitin::PhaseChaitin(uint unique, PhaseCFG &cfg, Matcher &matcher)
   : PhaseRegAlloc(unique, cfg, matcher,
 #ifndef PRODUCT
        print_chaitin_statistics
 #else
        NULL
 #endif
        )
   , _lrg_map(unique)
   , _live(0)
   , _spilled_once(Thread::current()->resource_area())
   , _spilled_twice(Thread::current()->resource_area())
   , _lo_degree(0), _lo_stk_degree(0), _hi_degree(0), _simplified(0)
   , _oldphi(unique)
 #ifndef PRODUCT
   , _trace_spilling(TraceSpilling || C->method_has_option("TraceSpilling"))
 #endif
 {
   NOT_PRODUCT( Compile::TracePhase t3("ctorChaitin", &_t_ctorChaitin, TimeCompiler); )
   _high_frequency_lrg = MIN2(float(OPTO_LRG_HIGH_FREQ), _cfg._outer_loop_freq);
   // Build a list of basic blocks, sorted by frequency
   _blks = NEW_RESOURCE_ARRAY( Block *, _cfg._num_blocks );
   // Experiment with sorting strategies to speed compilation
   double  cutoff = BLOCK_FREQUENCY(1.0); // Cutoff for high frequency bucket
   Block **buckets[NUMBUCKS];             // Array of buckets
   uint    buckcnt[NUMBUCKS];             // Array of bucket counters
   double  buckval[NUMBUCKS];             // Array of bucket value cutoffs
   for (uint i = 0; i < NUMBUCKS; i++) {
     buckets[i] = NEW_RESOURCE_ARRAY(Block *, _cfg._num_blocks);
     buckcnt[i] = 0;
     // Bump by three orders of magnitude each time
     cutoff *= 0.001;
     buckval[i] = cutoff;
     for (uint j = 0; j < _cfg._num_blocks; j++) {
       buckets[i][j] = NULL;
     }
   }
   // Sort blocks into buckets
   for (uint i = 0; i < _cfg._num_blocks; i++) {
     for (uint j = 0; j < NUMBUCKS; j++) {
       if ((j == NUMBUCKS - 1) || (_cfg._blocks[i]->_freq > buckval[j])) {
         // Assign block to end of list for appropriate bucket
         buckets[j][buckcnt[j]++] = _cfg._blocks[i];
         break; // kick out of inner loop
       }
     }
   }
   // Dump buckets into final block array
   uint blkcnt = 0;
   for (uint i = 0; i < NUMBUCKS; i++) {
     for (uint j = 0; j < buckcnt[i]; j++) {
       _blks[blkcnt++] = buckets[i][j];
     }
   }
   assert(blkcnt == _cfg._num_blocks, "Block array not totally filled");
 }
 //------------------------------Union------------------------------------------
 // union 2 sets together.
 void PhaseChaitin::Union( const Node *src_n, const Node *dst_n ) {
   uint src = _lrg_map.find(src_n);
   uint dst = _lrg_map.find(dst_n);
   assert(src, "");
   assert(dst, "");
   assert(src < _lrg_map.max_lrg_id(), "oob");
   assert(dst < _lrg_map.max_lrg_id(), "oob");
   assert(src < dst, "always union smaller");
   _lrg_map.uf_map(dst, src);
 }
 //------------------------------new_lrg----------------------------------------
 void PhaseChaitin::new_lrg(const Node *x, uint lrg) {
   // Make the Node->LRG mapping
   _lrg_map.extend(x->_idx,lrg);
   // Make the Union-Find mapping an identity function
   _lrg_map.uf_extend(lrg, lrg);
 }
 bool PhaseChaitin::clone_projs_shared(Block *b, uint idx, Node *con, Node *copy, uint max_lrg_id) {
   Block *bcon = _cfg._bbs[con->_idx];
   uint cindex = bcon->find_node(con);
   Node *con_next = bcon->_nodes[cindex+1];
   if (con_next->in(0) != con || !con_next->is_MachProj()) {
     return false;               // No MachProj's follow
   }
   // Copy kills after the cloned constant
   Node *kills = con_next->clone();
   kills->set_req(0, copy);
   b->_nodes.insert(idx, kills);
   _cfg._bbs.map(kills->_idx, b);
   new_lrg(kills, max_lrg_id);
   return true;
 }
 //------------------------------compact----------------------------------------
 // Renumber the live ranges to compact them.  Makes the IFG smaller.
 void PhaseChaitin::compact() {
   // Current the _uf_map contains a series of short chains which are headed
   // by a self-cycle.  All the chains run from big numbers to little numbers.
   // The Find() call chases the chains & shortens them for the next Find call.
   // We are going to change this structure slightly.  Numbers above a moving
   // wave 'i' are unchanged.  Numbers below 'j' point directly to their
   // compacted live range with no further chaining.  There are no chains or
   // cycles below 'i', so the Find call no longer works.
   uint j=1;
   uint i;
   for (i = 1; i < _lrg_map.max_lrg_id(); i++) {
     uint lr = _lrg_map.uf_live_range_id(i);
     // Ignore unallocated live ranges
     if (!lr) {
       continue;
     }
     assert(lr <= i, "");
     _lrg_map.uf_map(i, ( lr == i ) ? j++ : _lrg_map.uf_live_range_id(lr));
   }
   // Now change the Node->LR mapping to reflect the compacted names
   uint unique = _lrg_map.size();
   for (i = 0; i < unique; i++) {
     uint lrg_id = _lrg_map.live_range_id(i);
     _lrg_map.map(i, _lrg_map.uf_live_range_id(lrg_id));
   }
   // Reset the Union-Find mapping
   _lrg_map.reset_uf_map(j);
 }
 void PhaseChaitin::Register_Allocate() {
   // Above the OLD FP (and in registers) are the incoming arguments.  Stack
   // slots in this area are called "arg_slots".  Above the NEW FP (and in
   // registers) is the outgoing argument area; above that is the spill/temp
   // area.  These are all "frame_slots".  Arg_slots start at the zero
   // stack_slots and count up to the known arg_size.  Frame_slots start at
   // the stack_slot #arg_size and go up.  After allocation I map stack
   // slots to actual offsets.  Stack-slots in the arg_slot area are biased
   // by the frame_size; stack-slots in the frame_slot area are biased by 0.
   _trip_cnt = 0;
   _alternate = 0;
   _matcher._allocation_started = true;
   ResourceArea split_arena;     // Arena for Split local resources
   ResourceArea live_arena;      // Arena for liveness & IFG info
   ResourceMark rm(&live_arena);
   // Need live-ness for the IFG; need the IFG for coalescing.  If the
   // liveness is JUST for coalescing, then I can get some mileage by renaming
   // all copy-related live ranges low and then using the max copy-related
   // live range as a cut-off for LIVE and the IFG.  In other words, I can
   // build a subset of LIVE and IFG just for copies.
   PhaseLive live(_cfg, _lrg_map.names(), &live_arena);
   // Need IFG for coalescing and coloring
   PhaseIFG ifg(&live_arena);
   _ifg = &ifg;
   // Come out of SSA world to the Named world.  Assign (virtual) registers to
   // Nodes.  Use the same register for all inputs and the output of PhiNodes
   // - effectively ending SSA form.  This requires either coalescing live
   // ranges or inserting copies.  For the moment, we insert "virtual copies"
   // - we pretend there is a copy prior to each Phi in predecessor blocks.
   // We will attempt to coalesce such "virtual copies" before we manifest
   // them for real.
   de_ssa();
 #ifdef ASSERT
   // Veify the graph before RA.
   verify(&live_arena);
 #endif
   {
     NOT_PRODUCT( Compile::TracePhase t3("computeLive", &_t_computeLive, TimeCompiler); )
     _live = NULL;                 // Mark live as being not available
     rm.reset_to_mark();           // Reclaim working storage
     IndexSet::reset_memory(C, &live_arena);
     ifg.init(_lrg_map.max_lrg_id()); // Empty IFG
     gather_lrg_masks( false );    // Collect LRG masks
     live.compute(_lrg_map.max_lrg_id()); // Compute liveness
     _live = &live;                // Mark LIVE as being available
   }
   // Base pointers are currently "used" by instructions which define new
   // derived pointers.  This makes base pointers live up to the where the
   // derived pointer is made, but not beyond.  Really, they need to be live
   // across any GC point where the derived value is live.  So this code looks
   // at all the GC points, and "stretches" the live range of any base pointer
   // to the GC point.
   if (stretch_base_pointer_live_ranges(&live_arena)) {
     NOT_PRODUCT(Compile::TracePhase t3("computeLive (sbplr)", &_t_computeLive, TimeCompiler);)
     // Since some live range stretched, I need to recompute live
     _live = NULL;
     rm.reset_to_mark();         // Reclaim working storage
     IndexSet::reset_memory(C, &live_arena);
     ifg.init(_lrg_map.max_lrg_id());
     gather_lrg_masks(false);
     live.compute(_lrg_map.max_lrg_id());
     _live = &live;
   }
   // Create the interference graph using virtual copies
   build_ifg_virtual();  // Include stack slots this time
   // Aggressive (but pessimistic) copy coalescing.
   // This pass works on virtual copies.  Any virtual copies which are not
   // coalesced get manifested as actual copies
   {
     // The IFG is/was triangular.  I am 'squaring it up' so Union can run
     // faster.  Union requires a 'for all' operation which is slow on the
     // triangular adjacency matrix (quick reminder: the IFG is 'sparse' -
     // meaning I can visit all the Nodes neighbors less than a Node in time
     // O(# of neighbors), but I have to visit all the Nodes greater than a
     // given Node and search them for an instance, i.e., time O(#MaxLRG)).
     _ifg->SquareUp();
     PhaseAggressiveCoalesce coalesce(*this);
     coalesce.coalesce_driver();
     // Insert un-coalesced copies.  Visit all Phis.  Where inputs to a Phi do
     // not match the Phi itself, insert a copy.
     coalesce.insert_copies(_matcher);
   }
   // After aggressive coalesce, attempt a first cut at coloring.
   // To color, we need the IFG and for that we need LIVE.
   {
     NOT_PRODUCT( Compile::TracePhase t3("computeLive", &_t_computeLive, TimeCompiler); )
     _live = NULL;
     rm.reset_to_mark();           // Reclaim working storage
     IndexSet::reset_memory(C, &live_arena);
     ifg.init(_lrg_map.max_lrg_id());
     gather_lrg_masks( true );
     live.compute(_lrg_map.max_lrg_id());
     _live = &live;
   }
   // Build physical interference graph
   uint must_spill = 0;
   must_spill = build_ifg_physical(&live_arena);
   // If we have a guaranteed spill, might as well spill now
   if (must_spill) {
     if(!_lrg_map.max_lrg_id()) {
       return;
     }
     // Bail out if unique gets too large (ie - unique > MaxNodeLimit)
     C->check_node_count(10*must_spill, "out of nodes before split");
     if (C->failing()) {
       return;
     }
     uint new_max_lrg_id = Split(_lrg_map.max_lrg_id(), &split_arena);  // Split spilling LRG everywhere
     _lrg_map.set_max_lrg_id(new_max_lrg_id);
     // Bail out if unique gets too large (ie - unique > MaxNodeLimit - 2*NodeLimitFudgeFactor)
     // or we failed to split
     C->check_node_count(2*NodeLimitFudgeFactor, "out of nodes after physical split");
     if (C->failing()) {
       return;
     }
     NOT_PRODUCT(C->verify_graph_edges();)
     compact();                  // Compact LRGs; return new lower max lrg
     {
       NOT_PRODUCT( Compile::TracePhase t3("computeLive", &_t_computeLive, TimeCompiler); )
       _live = NULL;
       rm.reset_to_mark();         // Reclaim working storage
       IndexSet::reset_memory(C, &live_arena);
       ifg.init(_lrg_map.max_lrg_id()); // Build a new interference graph
       gather_lrg_masks( true );   // Collect intersect mask
       live.compute(_lrg_map.max_lrg_id()); // Compute LIVE
       _live = &live;
     }
     build_ifg_physical(&live_arena);
     _ifg->SquareUp();
     _ifg->Compute_Effective_Degree();
     // Only do conservative coalescing if requested
     if (OptoCoalesce) {
       // Conservative (and pessimistic) copy coalescing of those spills
       PhaseConservativeCoalesce coalesce(*this);
       // If max live ranges greater than cutoff, don't color the stack.
       // This cutoff can be larger than below since it is only done once.
       coalesce.coalesce_driver();
     }
     _lrg_map.compress_uf_map_for_nodes();
 #ifdef ASSERT
     verify(&live_arena, true);
 #endif
   } else {
     ifg.SquareUp();
     ifg.Compute_Effective_Degree();
 #ifdef ASSERT
     set_was_low();
 #endif
   }
   // Prepare for Simplify & Select
   cache_lrg_info();           // Count degree of LRGs
   // Simplify the InterFerence Graph by removing LRGs of low degree.
   // LRGs of low degree are trivially colorable.
   Simplify();
   // Select colors by re-inserting LRGs back into the IFG in reverse order.
   // Return whether or not something spills.
   uint spills = Select( );
   // If we spill, split and recycle the entire thing
   while( spills ) {
     if( _trip_cnt++ > 24 ) {
       DEBUG_ONLY( dump_for_spill_split_recycle(); )
       if( _trip_cnt > 27 ) {
         C->record_method_not_compilable("failed spill-split-recycle sanity check");
         return;
       }
     }
     if (!_lrg_map.max_lrg_id()) {
       return;
     }
     uint new_max_lrg_id = Split(_lrg_map.max_lrg_id(), &split_arena);  // Split spilling LRG everywhere
     _lrg_map.set_max_lrg_id(new_max_lrg_id);
     // Bail out if unique gets too large (ie - unique > MaxNodeLimit - 2*NodeLimitFudgeFactor)
     C->check_node_count(2 * NodeLimitFudgeFactor, "out of nodes after split");
     if (C->failing()) {
       return;
     }
     compact(); // Compact LRGs; return new lower max lrg
     // Nuke the live-ness and interference graph and LiveRanGe info
     {
       NOT_PRODUCT( Compile::TracePhase t3("computeLive", &_t_computeLive, TimeCompiler); )
       _live = NULL;
       rm.reset_to_mark();         // Reclaim working storage
       IndexSet::reset_memory(C, &live_arena);
       ifg.init(_lrg_map.max_lrg_id());
       // Create LiveRanGe array.
       // Intersect register masks for all USEs and DEFs
       gather_lrg_masks(true);
       live.compute(_lrg_map.max_lrg_id());
       _live = &live;
     }
     must_spill = build_ifg_physical(&live_arena);
     _ifg->SquareUp();
     _ifg->Compute_Effective_Degree();
     // Only do conservative coalescing if requested
     if (OptoCoalesce) {
       // Conservative (and pessimistic) copy coalescing
       PhaseConservativeCoalesce coalesce(*this);
       // Check for few live ranges determines how aggressive coalesce is.
       coalesce.coalesce_driver();
     }
     _lrg_map.compress_uf_map_for_nodes();
 #ifdef ASSERT
     verify(&live_arena, true);
 #endif
     cache_lrg_info();           // Count degree of LRGs
     // Simplify the InterFerence Graph by removing LRGs of low degree.
     // LRGs of low degree are trivially colorable.
     Simplify();
     // Select colors by re-inserting LRGs back into the IFG in reverse order.
     // Return whether or not something spills.
     spills = Select();
   }
   // Count number of Simplify-Select trips per coloring success.
   _allocator_attempts += _trip_cnt + 1;
   _allocator_successes += 1;
   // Peephole remove copies
   post_allocate_copy_removal();
 #ifdef ASSERT
   // Veify the graph after RA.
   verify(&live_arena);
 #endif
   // max_reg is past the largest *register* used.
   // Convert that to a frame_slot number.
   if (_max_reg <= _matcher._new_SP) {
     _framesize = C->out_preserve_stack_slots();
   }
   else {
     _framesize = _max_reg -_matcher._new_SP;
   }
   assert((int)(_matcher._new_SP+_framesize) >= (int)_matcher._out_arg_limit, "framesize must be large enough");
   // This frame must preserve the required fp alignment
   _framesize = round_to(_framesize, Matcher::stack_alignment_in_slots());
   assert( _framesize >= 0 && _framesize <= 1000000, "sanity check" );
 #ifndef PRODUCT
   _total_framesize += _framesize;
   if ((int)_framesize > _max_framesize) {
     _max_framesize = _framesize;
   }
 #endif
   // Convert CISC spills
   fixup_spills();
   // Log regalloc results
   CompileLog* log = Compile::current()->log();
   if (log != NULL) {
     log->elem("regalloc attempts='%d' success='%d'", _trip_cnt, !C->failing());
   }
   if (C->failing()) {
     return;
   }
   NOT_PRODUCT(C->verify_graph_edges();)
   // Move important info out of the live_arena to longer lasting storage.
   alloc_node_regs(_lrg_map.size());
   for (uint i=0; i < _lrg_map.size(); i++) {
     if (_lrg_map.live_range_id(i)) { // Live range associated with Node?
       LRG &lrg = lrgs(_lrg_map.live_range_id(i));
       if (!lrg.alive()) {
         set_bad(i);
       } else if (lrg.num_regs() == 1) {
         set1(i, lrg.reg());
       } else {                  // Must be a register-set
         if (!lrg._fat_proj) {   // Must be aligned adjacent register set
           // Live ranges record the highest register in their mask.
           // We want the low register for the AD file writer's convenience.
           OptoReg::Name hi = lrg.reg(); // Get hi register
           OptoReg::Name lo = OptoReg::add(hi, (1-lrg.num_regs())); // Find lo
           // We have to use pair [lo,lo+1] even for wide vectors because
           // the rest of code generation works only with pairs. It is safe
           // since for registers encoding only 'lo' is used.
           // Second reg from pair is used in ScheduleAndBundle on SPARC where
           // vector max size is 8 which corresponds to registers pair.
           // It is also used in BuildOopMaps but oop operations are not
           // vectorized.
           set2(i, lo);
         } else {                // Misaligned; extract 2 bits
           OptoReg::Name hi = lrg.reg(); // Get hi register
           lrg.Remove(hi);       // Yank from mask
           int lo = lrg.mask().find_first_elem(); // Find lo
           set_pair(i, hi, lo);
         }
       }
       if( lrg._is_oop ) _node_oops.set(i);
     } else {
       set_bad(i);
     }
   }
   // Done!
   _live = NULL;
   _ifg = NULL;
   C->set_indexSet_arena(NULL);  // ResourceArea is at end of scope
 }
 //------------------------------de_ssa-----------------------------------------
 void PhaseChaitin::de_ssa() {
   // Set initial Names for all Nodes.  Most Nodes get the virtual register
   // number.  A few get the ZERO live range number.  These do not
   // get allocated, but instead rely on correct scheduling to ensure that
   // only one instance is simultaneously live at a time.
   uint lr_counter = 1;
   for( uint i = 0; i < _cfg._num_blocks; i++ ) {
     Block *b = _cfg._blocks[i];
     uint cnt = b->_nodes.size();
     // Handle all the normal Nodes in the block
     for( uint j = 0; j < cnt; j++ ) {
       Node *n = b->_nodes[j];
       // Pre-color to the zero live range, or pick virtual register
       const RegMask &rm = n->out_RegMask();
       _lrg_map.map(n->_idx, rm.is_NotEmpty() ? lr_counter++ : 0);
     }
   }
   // Reset the Union-Find mapping to be identity
   _lrg_map.reset_uf_map(lr_counter);
 }
 //------------------------------gather_lrg_masks-------------------------------
 // Gather LiveRanGe information, including register masks.  Modification of
 // cisc spillable in_RegMasks should not be done before AggressiveCoalesce.
 void PhaseChaitin::gather_lrg_masks( bool after_aggressive ) {
   // Nail down the frame pointer live range
   uint fp_lrg = _lrg_map.live_range_id(_cfg._root->in(1)->in(TypeFunc::FramePtr));
   lrgs(fp_lrg)._cost += 1e12;   // Cost is infinite
   // For all blocks
   for( uint i = 0; i < _cfg._num_blocks; i++ ) {
     Block *b = _cfg._blocks[i];
     // For all instructions
     for( uint j = 1; j < b->_nodes.size(); j++ ) {
       Node *n = b->_nodes[j];
       uint input_edge_start =1; // Skip control most nodes
       if( n->is_Mach() ) input_edge_start = n->as_Mach()->oper_input_base();
       uint idx = n->is_Copy();
       // Get virtual register number, same as LiveRanGe index
       uint vreg = _lrg_map.live_range_id(n);
       LRG &lrg = lrgs(vreg);
       if( vreg ) {              // No vreg means un-allocable (e.g. memory)
         // Collect has-copy bit
         if( idx ) {
           lrg._has_copy = 1;
           uint clidx = _lrg_map.live_range_id(n->in(idx));
           LRG &copy_src = lrgs(clidx);
           copy_src._has_copy = 1;
         }
         // Check for float-vs-int live range (used in register-pressure
         // calculations)
         const Type *n_type = n->bottom_type();
         if (n_type->is_floatingpoint())
           lrg._is_float = 1;
         // Check for twice prior spilling.  Once prior spilling might have
         // spilled 'soft', 2nd prior spill should have spilled 'hard' and
         // further spilling is unlikely to make progress.
         if( _spilled_once.test(n->_idx) ) {
           lrg._was_spilled1 = 1;
           if( _spilled_twice.test(n->_idx) )
             lrg._was_spilled2 = 1;
         }
 #ifndef PRODUCT
         if (trace_spilling() && lrg._def != NULL) {
           // collect defs for MultiDef printing
           if (lrg._defs == NULL) {
             lrg._defs = new (_ifg->_arena) GrowableArray<Node*>(_ifg->_arena, 2, 0, NULL);
             lrg._defs->append(lrg._def);
           }
           lrg._defs->append(n);
         }
 #endif
         // Check for a single def LRG; these can spill nicely
         // via rematerialization.  Flag as NULL for no def found
         // yet, or 'n' for single def or -1 for many defs.
         lrg._def = lrg._def ? NodeSentinel : n;
         // Limit result register mask to acceptable registers
         const RegMask &rm = n->out_RegMask();
         lrg.AND( rm );
         int ireg = n->ideal_reg();
         assert( !n->bottom_type()->isa_oop_ptr() || ireg == Op_RegP,
                 "oops must be in Op_RegP's" );
         // Check for vector live range (only if vector register is used).
         // On SPARC vector uses RegD which could be misaligned so it is not
         // processes as vector in RA.
         if (RegMask::is_vector(ireg))
           lrg._is_vector = 1;
         assert(n_type->isa_vect() == NULL || lrg._is_vector || ireg == Op_RegD,
                "vector must be in vector registers");
         // Check for bound register masks
         const RegMask &lrgmask = lrg.mask();
         if (lrgmask.is_bound(ireg))
           lrg._is_bound = 1;
         // Check for maximum frequency value
         if (lrg._maxfreq < b->_freq)
           lrg._maxfreq = b->_freq;
         // Check for oop-iness, or long/double
         // Check for multi-kill projection
         switch( ireg ) {
         case MachProjNode::fat_proj:
           // Fat projections have size equal to number of registers killed
           lrg.set_num_regs(rm.Size());
           lrg.set_reg_pressure(lrg.num_regs());
           lrg._fat_proj = 1;
           lrg._is_bound = 1;
           break;
         case Op_RegP:
 #ifdef _LP64
           lrg.set_num_regs(2);  // Size is 2 stack words
 #else
           lrg.set_num_regs(1);  // Size is 1 stack word
 #endif
           // Register pressure is tracked relative to the maximum values
           // suggested for that platform, INTPRESSURE and FLOATPRESSURE,
           // and relative to other types which compete for the same regs.
           //
           // The following table contains suggested values based on the
           // architectures as defined in each .ad file.
           // INTPRESSURE and FLOATPRESSURE may be tuned differently for
           // compile-speed or performance.
           // Note1:
           // SPARC and SPARCV9 reg_pressures are at 2 instead of 1
           // since .ad registers are defined as high and low halves.
           // These reg_pressure values remain compatible with the code
           // in is_high_pressure() which relates get_invalid_mask_size(),
           // Block::_reg_pressure and INTPRESSURE, FLOATPRESSURE.
           // Note2:
           // SPARC -d32 has 24 registers available for integral values,
           // but only 10 of these are safe for 64-bit longs.
           // Using set_reg_pressure(2) for both int and long means
           // the allocator will believe it can fit 26 longs into
           // registers.  Using 2 for longs and 1 for ints means the
           // allocator will attempt to put 52 integers into registers.
           // The settings below limit this problem to methods with
           // many long values which are being run on 32-bit SPARC.
           //
           // ------------------- reg_pressure --------------------
           // Each entry is reg_pressure_per_value,number_of_regs
           //         RegL  RegI  RegFlags   RegF RegD    INTPRESSURE  FLOATPRESSURE
           // IA32     2     1     1          1    1          6           6
           // IA64     1     1     1          1    1         50          41
           // SPARC    2     2     2          2    2         48 (24)     52 (26)
           // SPARCV9  2     2     2          2    2         48 (24)     52 (26)
           // AMD64    1     1     1          1    1         14          15
           // -----------------------------------------------------
 #if defined(SPARC)
           lrg.set_reg_pressure(2);  // use for v9 as well
 #else
           lrg.set_reg_pressure(1);  // normally one value per register
 #endif
           if( n_type->isa_oop_ptr() ) {
             lrg._is_oop = 1;
           }
           break;
         case Op_RegL:           // Check for long or double
         case Op_RegD:
           lrg.set_num_regs(2);
           // Define platform specific register pressure
 #if defined(SPARC) || defined(ARM)
           lrg.set_reg_pressure(2);
 #elif defined(IA32)
           if( ireg == Op_RegL ) {
             lrg.set_reg_pressure(2);
           } else {
             lrg.set_reg_pressure(1);
           }
 #else
           lrg.set_reg_pressure(1);  // normally one value per register
 #endif
           // If this def of a double forces a mis-aligned double,
           // flag as '_fat_proj' - really flag as allowing misalignment
           // AND changes how we count interferences.  A mis-aligned
           // double can interfere with TWO aligned pairs, or effectively
           // FOUR registers!
           if (rm.is_misaligned_pair()) {
             lrg._fat_proj = 1;
             lrg._is_bound = 1;
           }
           break;
         case Op_RegF:
         case Op_RegI:
         case Op_RegN:
         case Op_RegFlags:
         case 0:                 // not an ideal register
           lrg.set_num_regs(1);
 #ifdef SPARC
           lrg.set_reg_pressure(2);
 #else
           lrg.set_reg_pressure(1);
 #endif
           break;
         case Op_VecS:
           assert(Matcher::vector_size_supported(T_BYTE,4), "sanity");
           assert(RegMask::num_registers(Op_VecS) == RegMask::SlotsPerVecS, "sanity");
           lrg.set_num_regs(RegMask::SlotsPerVecS);
           lrg.set_reg_pressure(1);
           break;
         case Op_VecD:
           assert(Matcher::vector_size_supported(T_FLOAT,RegMask::SlotsPerVecD), "sanity");
           assert(RegMask::num_registers(Op_VecD) == RegMask::SlotsPerVecD, "sanity");
           assert(lrgmask.is_aligned_sets(RegMask::SlotsPerVecD), "vector should be aligned");
           lrg.set_num_regs(RegMask::SlotsPerVecD);
           lrg.set_reg_pressure(1);
           break;
         case Op_VecX:
           assert(Matcher::vector_size_supported(T_FLOAT,RegMask::SlotsPerVecX), "sanity");
           assert(RegMask::num_registers(Op_VecX) == RegMask::SlotsPerVecX, "sanity");
           assert(lrgmask.is_aligned_sets(RegMask::SlotsPerVecX), "vector should be aligned");
           lrg.set_num_regs(RegMask::SlotsPerVecX);
           lrg.set_reg_pressure(1);
           break;
         case Op_VecY:
           assert(Matcher::vector_size_supported(T_FLOAT,RegMask::SlotsPerVecY), "sanity");
           assert(RegMask::num_registers(Op_VecY) == RegMask::SlotsPerVecY, "sanity");
           assert(lrgmask.is_aligned_sets(RegMask::SlotsPerVecY), "vector should be aligned");
           lrg.set_num_regs(RegMask::SlotsPerVecY);
           lrg.set_reg_pressure(1);
           break;
         default:
           ShouldNotReachHere();
         }
       }
       // Now do the same for inputs
       uint cnt = n->req();
       // Setup for CISC SPILLING
       uint inp = (uint)AdlcVMDeps::Not_cisc_spillable;
       if( UseCISCSpill && after_aggressive ) {
         inp = n->cisc_operand();
         if( inp != (uint)AdlcVMDeps::Not_cisc_spillable )
           // Convert operand number to edge index number
           inp = n->as_Mach()->operand_index(inp);
       }
       // Prepare register mask for each input
       for( uint k = input_edge_start; k < cnt; k++ ) {
         uint vreg = _lrg_map.live_range_id(n->in(k));
         if (!vreg) {
           continue;
         }
         // If this instruction is CISC Spillable, add the flags
         // bit to its appropriate input
         if( UseCISCSpill && after_aggressive && inp == k ) {
 #ifndef PRODUCT
           if( TraceCISCSpill ) {
             tty->print("  use_cisc_RegMask: ");
             n->dump();
           }
 #endif
           n->as_Mach()->use_cisc_RegMask();
         }
         LRG &lrg = lrgs(vreg);
         // // Testing for floating point code shape
         // Node *test = n->in(k);
         // if( test->is_Mach() ) {
         //   MachNode *m = test->as_Mach();
         //   int  op = m->ideal_Opcode();
         //   if (n->is_Call() && (op == Op_AddF || op == Op_MulF) ) {
         //     int zzz = 1;
         //   }
         // }
         // Limit result register mask to acceptable registers.
         // Do not limit registers from uncommon uses before
         // AggressiveCoalesce.  This effectively pre-virtual-splits
         // around uncommon uses of common defs.
         const RegMask &rm = n->in_RegMask(k);
         if( !after_aggressive &&
           _cfg._bbs[n->in(k)->_idx]->_freq > 1000*b->_freq ) {
           // Since we are BEFORE aggressive coalesce, leave the register
           // mask untrimmed by the call.  This encourages more coalescing.
           // Later, AFTER aggressive, this live range will have to spill
           // but the spiller handles slow-path calls very nicely.
         } else {
           lrg.AND( rm );
         }
         // Check for bound register masks
         const RegMask &lrgmask = lrg.mask();
         int kreg = n->in(k)->ideal_reg();
         bool is_vect = RegMask::is_vector(kreg);
         assert(n->in(k)->bottom_type()->isa_vect() == NULL ||
                is_vect || kreg == Op_RegD,
                "vector must be in vector registers");
         if (lrgmask.is_bound(kreg))
           lrg._is_bound = 1;
         // If this use of a double forces a mis-aligned double,
         // flag as '_fat_proj' - really flag as allowing misalignment
         // AND changes how we count interferences.  A mis-aligned
         // double can interfere with TWO aligned pairs, or effectively
         // FOUR registers!
 #ifdef ASSERT
         if (is_vect) {
           assert(lrgmask.is_aligned_sets(lrg.num_regs()), "vector should be aligned");
           assert(!lrg._fat_proj, "sanity");
           assert(RegMask::num_registers(kreg) == lrg.num_regs(), "sanity");
         }
 #endif
         if (!is_vect && lrg.num_regs() == 2 && !lrg._fat_proj && rm.is_misaligned_pair()) {
           lrg._fat_proj = 1;
           lrg._is_bound = 1;
         }
         // if the LRG is an unaligned pair, we will have to spill
         // so clear the LRG's register mask if it is not already spilled
         if (!is_vect && !n->is_SpillCopy() &&
             (lrg._def == NULL || lrg.is_multidef() || !lrg._def->is_SpillCopy()) &&
             lrgmask.is_misaligned_pair()) {
           lrg.Clear();
         }
         // Check for maximum frequency value
         if( lrg._maxfreq < b->_freq )
           lrg._maxfreq = b->_freq;
       } // End for all allocated inputs
     } // end for all instructions
   } // end for all blocks
   // Final per-liverange setup
   for (uint i2 = 0; i2 < _lrg_map.max_lrg_id(); i2++) {
     LRG &lrg = lrgs(i2);
     assert(!lrg._is_vector || !lrg._fat_proj, "sanity");
     if (lrg.num_regs() > 1 && !lrg._fat_proj) {
       lrg.clear_to_sets();
     }
     lrg.compute_set_mask_size();
     if (lrg.not_free()) {      // Handle case where we lose from the start
       lrg.set_reg(OptoReg::Name(LRG::SPILL_REG));
       lrg._direct_conflict = 1;
     }
     lrg.set_degree(0);          // no neighbors in IFG yet
   }
 }
 //------------------------------set_was_low------------------------------------
 // Set the was-lo-degree bit.  Conservative coalescing should not change the
 // colorability of the graph.  If any live range was of low-degree before
 // coalescing, it should Simplify.  This call sets the was-lo-degree bit.
 // The bit is checked in Simplify.
 void PhaseChaitin::set_was_low() {
 #ifdef ASSERT
   for (uint i = 1; i < _lrg_map.max_lrg_id(); i++) {
     int size = lrgs(i).num_regs();
     uint old_was_lo = lrgs(i)._was_lo;
     lrgs(i)._was_lo = 0;
     if( lrgs(i).lo_degree() ) {
       lrgs(i)._was_lo = 1;      // Trivially of low degree
     } else {                    // Else check the Brigg's assertion
       // Brigg's observation is that the lo-degree neighbors of a
       // hi-degree live range will not interfere with the color choices
       // of said hi-degree live range.  The Simplify reverse-stack-coloring
       // order takes care of the details.  Hence you do not have to count
       // low-degree neighbors when determining if this guy colors.
       int briggs_degree = 0;
       IndexSet *s = _ifg->neighbors(i);
       IndexSetIterator elements(s);
       uint lidx;
       while((lidx = elements.next()) != 0) {
         if( !lrgs(lidx).lo_degree() )
           briggs_degree += MAX2(size,lrgs(lidx).num_regs());
       }
       if( briggs_degree < lrgs(i).degrees_of_freedom() )
         lrgs(i)._was_lo = 1;    // Low degree via the briggs assertion
     }
     assert(old_was_lo <= lrgs(i)._was_lo, "_was_lo may not decrease");
   }
 #endif
 }
 #define REGISTER_CONSTRAINED 16
 //------------------------------cache_lrg_info---------------------------------
 // Compute cost/area ratio, in case we spill.  Build the lo-degree list.
 void PhaseChaitin::cache_lrg_info( ) {
   for (uint i = 1; i < _lrg_map.max_lrg_id(); i++) {
     LRG &lrg = lrgs(i);
     // Check for being of low degree: means we can be trivially colored.
     // Low degree, dead or must-spill guys just get to simplify right away
     if( lrg.lo_degree() ||
        !lrg.alive() ||
         lrg._must_spill ) {
       // Split low degree list into those guys that must get a
       // register and those that can go to register or stack.
       // The idea is LRGs that can go register or stack color first when
       // they have a good chance of getting a register.  The register-only
       // lo-degree live ranges always get a register.
       OptoReg::Name hi_reg = lrg.mask().find_last_elem();
       if( OptoReg::is_stack(hi_reg)) { // Can go to stack?
         lrg._next = _lo_stk_degree;
         _lo_stk_degree = i;
       } else {
         lrg._next = _lo_degree;
         _lo_degree = i;
       }
     } else {                    // Else high degree
       lrgs(_hi_degree)._prev = i;
       lrg._next = _hi_degree;
       lrg._prev = 0;
       _hi_degree = i;
     }
   }
 }
 //------------------------------Pre-Simplify-----------------------------------
 // Simplify the IFG by removing LRGs of low degree that have NO copies
 void PhaseChaitin::Pre_Simplify( ) {
   // Warm up the lo-degree no-copy list
   int lo_no_copy = 0;
   for (uint i = 1; i < _lrg_map.max_lrg_id(); i++) {
     if ((lrgs(i).lo_degree() && !lrgs(i)._has_copy) ||
         !lrgs(i).alive() ||
         lrgs(i)._must_spill) {
       lrgs(i)._next = lo_no_copy;
       lo_no_copy = i;
     }
   }
   while( lo_no_copy ) {
     uint lo = lo_no_copy;
     lo_no_copy = lrgs(lo)._next;
     int size = lrgs(lo).num_regs();
     // Put the simplified guy on the simplified list.
     lrgs(lo)._next = _simplified;
     _simplified = lo;
     // Yank this guy from the IFG.
     IndexSet *adj = _ifg->remove_node( lo );
     // If any neighbors' degrees fall below their number of
     // allowed registers, then put that neighbor on the low degree
     // list.  Note that 'degree' can only fall and 'numregs' is
     // unchanged by this action.  Thus the two are equal at most once,
     // so LRGs hit the lo-degree worklists at most once.
     IndexSetIterator elements(adj);
     uint neighbor;
     while ((neighbor = elements.next()) != 0) {
       LRG *n = &lrgs(neighbor);
       assert( _ifg->effective_degree(neighbor) == n->degree(), "" );
       // Check for just becoming of-low-degree
       if( n->just_lo_degree() && !n->_has_copy ) {
         assert(!(*_ifg->_yanked)[neighbor],"Cannot move to lo degree twice");
         // Put on lo-degree list
         n->_next = lo_no_copy;
         lo_no_copy = neighbor;
       }
     }
   } // End of while lo-degree no_copy worklist not empty
   // No more lo-degree no-copy live ranges to simplify
 }
 //------------------------------Simplify---------------------------------------
 // Simplify the IFG by removing LRGs of low degree.
 void PhaseChaitin::Simplify( ) {
   while( 1 ) {                  // Repeat till simplified it all
     // May want to explore simplifying lo_degree before _lo_stk_degree.
     // This might result in more spills coloring into registers during
     // Select().
     while( _lo_degree || _lo_stk_degree ) {
       // If possible, pull from lo_stk first
       uint lo;
       if( _lo_degree ) {
         lo = _lo_degree;
         _lo_degree = lrgs(lo)._next;
       } else {
         lo = _lo_stk_degree;
         _lo_stk_degree = lrgs(lo)._next;
       }
       // Put the simplified guy on the simplified list.
       lrgs(lo)._next = _simplified;
       _simplified = lo;
       // If this guy is "at risk" then mark his current neighbors
       if( lrgs(lo)._at_risk ) {
         IndexSetIterator elements(_ifg->neighbors(lo));
         uint datum;
         while ((datum = elements.next()) != 0) {
           lrgs(datum)._risk_bias = lo;
         }
       }
       // Yank this guy from the IFG.
       IndexSet *adj = _ifg->remove_node( lo );
       // If any neighbors' degrees fall below their number of
       // allowed registers, then put that neighbor on the low degree
       // list.  Note that 'degree' can only fall and 'numregs' is
       // unchanged by this action.  Thus the two are equal at most once,
       // so LRGs hit the lo-degree worklist at most once.
       IndexSetIterator elements(adj);
       uint neighbor;
       while ((neighbor = elements.next()) != 0) {
         LRG *n = &lrgs(neighbor);
 #ifdef ASSERT
         if( VerifyOpto || VerifyRegisterAllocator ) {
           assert( _ifg->effective_degree(neighbor) == n->degree(), "" );
         }
 #endif
         // Check for just becoming of-low-degree just counting registers.
         // _must_spill live ranges are already on the low degree list.
         if( n->just_lo_degree() && !n->_must_spill ) {
           assert(!(*_ifg->_yanked)[neighbor],"Cannot move to lo degree twice");
           // Pull from hi-degree list
           uint prev = n->_prev;
           uint next = n->_next;
           if( prev ) lrgs(prev)._next = next;
           else _hi_degree = next;
           lrgs(next)._prev = prev;
           n->_next = _lo_degree;
           _lo_degree = neighbor;
         }
       }
     } // End of while lo-degree/lo_stk_degree worklist not empty
     // Check for got everything: is hi-degree list empty?
     if( !_hi_degree ) break;
     // Time to pick a potential spill guy
     uint lo_score = _hi_degree;
     double score = lrgs(lo_score).score();
     double area = lrgs(lo_score)._area;
     double cost = lrgs(lo_score)._cost;
     bool bound = lrgs(lo_score)._is_bound;
     // Find cheapest guy
     debug_only( int lo_no_simplify=0; );
     for( uint i = _hi_degree; i; i = lrgs(i)._next ) {
       assert( !(*_ifg->_yanked)[i], "" );
       // It's just vaguely possible to move hi-degree to lo-degree without
       // going through a just-lo-degree stage: If you remove a double from
       // a float live range it's degree will drop by 2 and you can skip the
       // just-lo-degree stage.  It's very rare (shows up after 5000+ methods
       // in -Xcomp of Java2Demo).  So just choose this guy to simplify next.
       if( lrgs(i).lo_degree() ) {
         lo_score = i;
         break;
       }
       debug_only( if( lrgs(i)._was_lo ) lo_no_simplify=i; );
       double iscore = lrgs(i).score();
       double iarea = lrgs(i)._area;
       double icost = lrgs(i)._cost;
       bool ibound = lrgs(i)._is_bound;
       // Compare cost/area of i vs cost/area of lo_score.  Smaller cost/area
       // wins.  Ties happen because all live ranges in question have spilled
       // a few times before and the spill-score adds a huge number which
       // washes out the low order bits.  We are choosing the lesser of 2
       // evils; in this case pick largest area to spill.
       // Ties also happen when live ranges are defined and used only inside
       // one block. In which case their area is 0 and score set to max.
       // In such case choose bound live range over unbound to free registers
       // or with smaller cost to spill.
       if( iscore < score ||
           (iscore == score && iarea > area && lrgs(lo_score)._was_spilled2) ||
           (iscore == score && iarea == area &&
            ( (ibound && !bound) || ibound == bound && (icost < cost) )) ) {
         lo_score = i;
         score = iscore;
         area = iarea;
         cost = icost;
         bound = ibound;
       }
     }
     LRG *lo_lrg = &lrgs(lo_score);
     // The live range we choose for spilling is either hi-degree, or very
     // rarely it can be low-degree.  If we choose a hi-degree live range
     // there better not be any lo-degree choices.
     assert( lo_lrg->lo_degree() || !lo_no_simplify, "Live range was lo-degree before coalesce; should simplify" );
     // Pull from hi-degree list
     uint prev = lo_lrg->_prev;
     uint next = lo_lrg->_next;
     if( prev ) lrgs(prev)._next = next;
     else _hi_degree = next;
     lrgs(next)._prev = prev;
     // Jam him on the lo-degree list, despite his high degree.
     // Maybe he'll get a color, and maybe he'll spill.
     // Only Select() will know.
     lrgs(lo_score)._at_risk = true;
     _lo_degree = lo_score;
     lo_lrg->_next = 0;
   } // End of while not simplified everything
 }
 //------------------------------is_legal_reg-----------------------------------
 // Is 'reg' register legal for 'lrg'?
 static bool is_legal_reg(LRG &lrg, OptoReg::Name reg, int chunk) {
   if (reg >= chunk && reg < (chunk + RegMask::CHUNK_SIZE) &&
       lrg.mask().Member(OptoReg::add(reg,-chunk))) {
     // RA uses OptoReg which represent the highest element of a registers set.
     // For example, vectorX (128bit) on x86 uses [XMM,XMMb,XMMc,XMMd] set
     // in which XMMd is used by RA to represent such vectors. A double value
     // uses [XMM,XMMb] pairs and XMMb is used by RA for it.
     // The register mask uses largest bits set of overlapping register sets.
     // On x86 with AVX it uses 8 bits for each XMM registers set.
     //
     // The 'lrg' already has cleared-to-set register mask (done in Select()
     // before calling choose_color()). Passing mask.Member(reg) check above
     // indicates that the size (num_regs) of 'reg' set is less or equal to
     // 'lrg' set size.
     // For set size 1 any register which is member of 'lrg' mask is legal.
     if (lrg.num_regs()==1)
       return true;
     // For larger sets only an aligned register with the same set size is legal.
     int mask = lrg.num_regs()-1;
     if ((reg&mask) == mask)
       return true;
   }
   return false;
 }
 //------------------------------bias_color-------------------------------------
 // Choose a color using the biasing heuristic
 OptoReg::Name PhaseChaitin::bias_color( LRG &lrg, int chunk ) {
   // Check for "at_risk" LRG's
   uint risk_lrg = _lrg_map.find(lrg._risk_bias);
   if( risk_lrg != 0 ) {
     // Walk the colored neighbors of the "at_risk" candidate
     // Choose a color which is both legal and already taken by a neighbor
     // of the "at_risk" candidate in order to improve the chances of the
     // "at_risk" candidate of coloring
     IndexSetIterator elements(_ifg->neighbors(risk_lrg));
     uint datum;
     while ((datum = elements.next()) != 0) {
       OptoReg::Name reg = lrgs(datum).reg();
       // If this LRG's register is legal for us, choose it
       if (is_legal_reg(lrg, reg, chunk))
         return reg;
     }
   }
   uint copy_lrg = _lrg_map.find(lrg._copy_bias);
   if( copy_lrg != 0 ) {
     // If he has a color,
     if( !(*(_ifg->_yanked))[copy_lrg] ) {
       OptoReg::Name reg = lrgs(copy_lrg).reg();
       //  And it is legal for you,
       if (is_legal_reg(lrg, reg, chunk))
         return reg;
     } else if( chunk == 0 ) {
       // Choose a color which is legal for him
       RegMask tempmask = lrg.mask();
       tempmask.AND(lrgs(copy_lrg).mask());
       tempmask.clear_to_sets(lrg.num_regs());
       OptoReg::Name reg = tempmask.find_first_set(lrg.num_regs());
       if (OptoReg::is_valid(reg))
         return reg;
     }
   }
   // If no bias info exists, just go with the register selection ordering
   if (lrg._is_vector || lrg.num_regs() == 2) {
     // Find an aligned set
     return OptoReg::add(lrg.mask().find_first_set(lrg.num_regs()),chunk);
   }
   // CNC - Fun hack.  Alternate 1st and 2nd selection.  Enables post-allocate
   // copy removal to remove many more copies, by preventing a just-assigned
   // register from being repeatedly assigned.
   OptoReg::Name reg = lrg.mask().find_first_elem();
   if( (++_alternate & 1) && OptoReg::is_valid(reg) ) {
     // This 'Remove; find; Insert' idiom is an expensive way to find the
     // SECOND element in the mask.
     lrg.Remove(reg);
     OptoReg::Name reg2 = lrg.mask().find_first_elem();
     lrg.Insert(reg);
     if( OptoReg::is_reg(reg2))
       reg = reg2;
   }
   return OptoReg::add( reg, chunk );
 }
 //------------------------------choose_color-----------------------------------
 // Choose a color in the current chunk
 OptoReg::Name PhaseChaitin::choose_color( LRG &lrg, int chunk ) {
   assert( C->in_preserve_stack_slots() == 0 || chunk != 0 || lrg._is_bound || lrg.mask().is_bound1() || !lrg.mask().Member(OptoReg::Name(_matcher._old_SP-1)), "must not allocate stack0 (inside preserve area)");
   assert(C->out_preserve_stack_slots() == 0 || chunk != 0 || lrg._is_bound || lrg.mask().is_bound1() || !lrg.mask().Member(OptoReg::Name(_matcher._old_SP+0)), "must not allocate stack0 (inside preserve area)");
   if( lrg.num_regs() == 1 ||    // Common Case
       !lrg._fat_proj )          // Aligned+adjacent pairs ok
     // Use a heuristic to "bias" the color choice
     return bias_color(lrg, chunk);
   assert(!lrg._is_vector, "should be not vector here" );
   assert( lrg.num_regs() >= 2, "dead live ranges do not color" );
   // Fat-proj case or misaligned double argument.
   assert(lrg.compute_mask_size() == lrg.num_regs() ||
          lrg.num_regs() == 2,"fat projs exactly color" );
   assert( !chunk, "always color in 1st chunk" );
   // Return the highest element in the set.
   return lrg.mask().find_last_elem();
 }
 //------------------------------Select-----------------------------------------
 // Select colors by re-inserting LRGs back into the IFG.  LRGs are re-inserted
 // in reverse order of removal.  As long as nothing of hi-degree was yanked,
 // everything going back is guaranteed a color.  Select that color.  If some
 // hi-degree LRG cannot get a color then we record that we must spill.
 uint PhaseChaitin::Select( ) {
   uint spill_reg = LRG::SPILL_REG;
   _max_reg = OptoReg::Name(0);  // Past max register used
   while( _simplified ) {
     // Pull next LRG from the simplified list - in reverse order of removal
     uint lidx = _simplified;
     LRG *lrg = &lrgs(lidx);
     _simplified = lrg->_next;
 #ifndef PRODUCT
     if (trace_spilling()) {
       ttyLocker ttyl;
       tty->print_cr("L%d selecting degree %d degrees_of_freedom %d", lidx, lrg->degree(),
                     lrg->degrees_of_freedom());
       lrg->dump();
     }
 #endif
     // Re-insert into the IFG
     _ifg->re_insert(lidx);
     if( !lrg->alive() ) continue;
     // capture allstackedness flag before mask is hacked
     const int is_allstack = lrg->mask().is_AllStack();
     // Yeah, yeah, yeah, I know, I know.  I can refactor this
     // to avoid the GOTO, although the refactored code will not
     // be much clearer.  We arrive here IFF we have a stack-based
     // live range that cannot color in the current chunk, and it
     // has to move into the next free stack chunk.
     int chunk = 0;              // Current chunk is first chunk
     retry_next_chunk:
     // Remove neighbor colors
     IndexSet *s = _ifg->neighbors(lidx);
     debug_only(RegMask orig_mask = lrg->mask();)
     IndexSetIterator elements(s);
     uint neighbor;
     while ((neighbor = elements.next()) != 0) {
       // Note that neighbor might be a spill_reg.  In this case, exclusion
       // of its color will be a no-op, since the spill_reg chunk is in outer
       // space.  Also, if neighbor is in a different chunk, this exclusion
       // will be a no-op.  (Later on, if lrg runs out of possible colors in
       // its chunk, a new chunk of color may be tried, in which case
       // examination of neighbors is started again, at retry_next_chunk.)
       LRG &nlrg = lrgs(neighbor);
       OptoReg::Name nreg = nlrg.reg();
       // Only subtract masks in the same chunk
       if( nreg >= chunk && nreg < chunk + RegMask::CHUNK_SIZE ) {
 #ifndef PRODUCT
         uint size = lrg->mask().Size();
         RegMask rm = lrg->mask();
 #endif
         lrg->SUBTRACT(nlrg.mask());
 #ifndef PRODUCT
         if (trace_spilling() && lrg->mask().Size() != size) {
           ttyLocker ttyl;
           tty->print("L%d ", lidx);
           rm.dump();
           tty->print(" intersected L%d ", neighbor);
           nlrg.mask().dump();
           tty->print(" removed ");
           rm.SUBTRACT(lrg->mask());
           rm.dump();
           tty->print(" leaving ");
           lrg->mask().dump();
           tty->cr();
         }
 #endif
       }
     }
     //assert(is_allstack == lrg->mask().is_AllStack(), "nbrs must not change AllStackedness");
     // Aligned pairs need aligned masks
     assert(!lrg->_is_vector || !lrg->_fat_proj, "sanity");
     if (lrg->num_regs() > 1 && !lrg->_fat_proj) {
       lrg->clear_to_sets();
     }
     // Check if a color is available and if so pick the color
     OptoReg::Name reg = choose_color( *lrg, chunk );
 #ifdef SPARC
     debug_only(lrg->compute_set_mask_size());
     assert(lrg->num_regs() < 2 || lrg->is_bound() || is_even(reg-1), "allocate all doubles aligned");
 #endif
     //---------------
     // If we fail to color and the AllStack flag is set, trigger
     // a chunk-rollover event
     if(!OptoReg::is_valid(OptoReg::add(reg,-chunk)) && is_allstack) {
       // Bump register mask up to next stack chunk
       chunk += RegMask::CHUNK_SIZE;
       lrg->Set_All();
       goto retry_next_chunk;
     }
     //---------------
     // Did we get a color?
     else if( OptoReg::is_valid(reg)) {
 #ifndef PRODUCT
       RegMask avail_rm = lrg->mask();
 #endif
       // Record selected register
       lrg->set_reg(reg);
       if( reg >= _max_reg )     // Compute max register limit
         _max_reg = OptoReg::add(reg,1);
       // Fold reg back into normal space
       reg = OptoReg::add(reg,-chunk);
       // If the live range is not bound, then we actually had some choices
       // to make.  In this case, the mask has more bits in it than the colors
       // chosen.  Restrict the mask to just what was picked.
       int n_regs = lrg->num_regs();
       assert(!lrg->_is_vector || !lrg->_fat_proj, "sanity");
       if (n_regs == 1 || !lrg->_fat_proj) {
         assert(!lrg->_is_vector || n_regs <= RegMask::SlotsPerVecY, "sanity");
         lrg->Clear();           // Clear the mask
         lrg->Insert(reg);       // Set regmask to match selected reg
         // For vectors and pairs, also insert the low bit of the pair
         for (int i = 1; i < n_regs; i++)
           lrg->Insert(OptoReg::add(reg,-i));
         lrg->set_mask_size(n_regs);
       } else {                  // Else fatproj
         // mask must be equal to fatproj bits, by definition
       }
 #ifndef PRODUCT
       if (trace_spilling()) {
         ttyLocker ttyl;
         tty->print("L%d selected ", lidx);
         lrg->mask().dump();
         tty->print(" from ");
         avail_rm.dump();
         tty->cr();
       }
 #endif
       // Note that reg is the highest-numbered register in the newly-bound mask.
     } // end color available case
     //---------------
     // Live range is live and no colors available
     else {
       assert( lrg->alive(), "" );
       assert( !lrg->_fat_proj || lrg->is_multidef() ||
               lrg->_def->outcnt() > 0, "fat_proj cannot spill");
       assert( !orig_mask.is_AllStack(), "All Stack does not spill" );
       // Assign the special spillreg register
       lrg->set_reg(OptoReg::Name(spill_reg++));
       // Do not empty the regmask; leave mask_size lying around
       // for use during Spilling
 #ifndef PRODUCT
       if( trace_spilling() ) {
         ttyLocker ttyl;
         tty->print("L%d spilling with neighbors: ", lidx);
         s->dump();
         debug_only(tty->print(" original mask: "));
         debug_only(orig_mask.dump());
         dump_lrg(lidx);
       }
 #endif
     } // end spill case
   }
   return spill_reg-LRG::SPILL_REG;      // Return number of spills
 }
 //------------------------------copy_was_spilled-------------------------------
 // Copy 'was_spilled'-edness from the source Node to the dst Node.
 void PhaseChaitin::copy_was_spilled( Node *src, Node *dst ) {
   if( _spilled_once.test(src->_idx) ) {
     _spilled_once.set(dst->_idx);
     lrgs(_lrg_map.find(dst))._was_spilled1 = 1;
     if( _spilled_twice.test(src->_idx) ) {
       _spilled_twice.set(dst->_idx);
       lrgs(_lrg_map.find(dst))._was_spilled2 = 1;
     }
   }
 }
 //------------------------------set_was_spilled--------------------------------
 // Set the 'spilled_once' or 'spilled_twice' flag on a node.
 void PhaseChaitin::set_was_spilled( Node *n ) {
   if( _spilled_once.test_set(n->_idx) )
     _spilled_twice.set(n->_idx);
 }
 //------------------------------fixup_spills-----------------------------------
 // Convert Ideal spill instructions into proper FramePtr + offset Loads and
 // Stores.  Use-def chains are NOT preserved, but Node->LRG->reg maps are.
 void PhaseChaitin::fixup_spills() {
   // This function does only cisc spill work.
   if( !UseCISCSpill ) return;
   NOT_PRODUCT( Compile::TracePhase t3("fixupSpills", &_t_fixupSpills, TimeCompiler); )
   // Grab the Frame Pointer
   Node *fp = _cfg._broot->head()->in(1)->in(TypeFunc::FramePtr);
   // For all blocks
   for( uint i = 0; i < _cfg._num_blocks; i++ ) {
     Block *b = _cfg._blocks[i];
     // For all instructions in block
     uint last_inst = b->end_idx();
     for( uint j = 1; j <= last_inst; j++ ) {
       Node *n = b->_nodes[j];
       // Dead instruction???
       assert( n->outcnt() != 0 ||// Nothing dead after post alloc
               C->top() == n ||  // Or the random TOP node
               n->is_Proj(),     // Or a fat-proj kill node
               "No dead instructions after post-alloc" );
       int inp = n->cisc_operand();
       if( inp != AdlcVMDeps::Not_cisc_spillable ) {
         // Convert operand number to edge index number
         MachNode *mach = n->as_Mach();
         inp = mach->operand_index(inp);
         Node *src = n->in(inp);   // Value to load or store
         LRG &lrg_cisc = lrgs(_lrg_map.find_const(src));
         OptoReg::Name src_reg = lrg_cisc.reg();
         // Doubles record the HIGH register of an adjacent pair.
         src_reg = OptoReg::add(src_reg,1-lrg_cisc.num_regs());
         if( OptoReg::is_stack(src_reg) ) { // If input is on stack
           // This is a CISC Spill, get stack offset and construct new node
 #ifndef PRODUCT
           if( TraceCISCSpill ) {
             tty->print("    reg-instr:  ");
             n->dump();
           }
 #endif
           int stk_offset = reg2offset(src_reg);
           // Bailout if we might exceed node limit when spilling this instruction
           C->check_node_count(0, "out of nodes fixing spills");
           if (C->failing())  return;
           // Transform node
           MachNode *cisc = mach->cisc_version(stk_offset, C)->as_Mach();
           cisc->set_req(inp,fp);          // Base register is frame pointer
           if( cisc->oper_input_base() > 1 && mach->oper_input_base() <= 1 ) {
             assert( cisc->oper_input_base() == 2, "Only adding one edge");
             cisc->ins_req(1,src);         // Requires a memory edge
           }
           b->_nodes.map(j,cisc);          // Insert into basic block
           n->subsume_by(cisc, C); // Correct graph
           //
           ++_used_cisc_instructions;
 #ifndef PRODUCT
           if( TraceCISCSpill ) {
             tty->print("    cisc-instr: ");
             cisc->dump();
           }
 #endif
         } else {
 #ifndef PRODUCT
           if( TraceCISCSpill ) {
             tty->print("    using reg-instr: ");
             n->dump();
           }
 #endif
           ++_unused_cisc_instructions;    // input can be on stack
         }
       }
     } // End of for all instructions
   } // End of for all blocks
 }
 //------------------------------find_base_for_derived--------------------------
 // Helper to stretch above; recursively discover the base Node for a
 // given derived Node.  Easy for AddP-related machine nodes, but needs
 // to be recursive for derived Phis.
 Node *PhaseChaitin::find_base_for_derived( Node **derived_base_map, Node *derived, uint &maxlrg ) {
   // See if already computed; if so return it
   if( derived_base_map[derived->_idx] )
     return derived_base_map[derived->_idx];
   // See if this happens to be a base.
   // NOTE: we use TypePtr instead of TypeOopPtr because we can have
   // pointers derived from NULL!  These are always along paths that
   // can't happen at run-time but the optimizer cannot deduce it so
   // we have to handle it gracefully.
   assert(!derived->bottom_type()->isa_narrowoop() ||
           derived->bottom_type()->make_ptr()->is_ptr()->_offset == 0, "sanity");
   const TypePtr *tj = derived->bottom_type()->isa_ptr();
   // If its an OOP with a non-zero offset, then it is derived.
   if( tj == NULL || tj->_offset == 0 ) {
     derived_base_map[derived->_idx] = derived;
     return derived;
   }
   // Derived is NULL+offset?  Base is NULL!
   if( derived->is_Con() ) {
     Node *base = _matcher.mach_null();
     assert(base != NULL, "sanity");
     if (base->in(0) == NULL) {
       // Initialize it once and make it shared:
       // set control to _root and place it into Start block
       // (where top() node is placed).
       base->init_req(0, _cfg._root);
       Block *startb = _cfg._bbs[C->top()->_idx];
       startb->_nodes.insert(startb->find_node(C->top()), base );
       _cfg._bbs.map( base->_idx, startb );
       assert(_lrg_map.live_range_id(base) == 0, "should not have LRG yet");
     }
     if (_lrg_map.live_range_id(base) == 0) {
       new_lrg(base, maxlrg++);
     }
     assert(base->in(0) == _cfg._root &&
            _cfg._bbs[base->_idx] == _cfg._bbs[C->top()->_idx], "base NULL should be shared");
     derived_base_map[derived->_idx] = base;
     return base;
   }
   // Check for AddP-related opcodes
   if (!derived->is_Phi()) {
     assert(derived->as_Mach()->ideal_Opcode() == Op_AddP, err_msg_res("but is: %s", derived->Name()));
     Node *base = derived->in(AddPNode::Base);
     derived_base_map[derived->_idx] = base;
     return base;
   }
   // Recursively find bases for Phis.
   // First check to see if we can avoid a base Phi here.
   Node *base = find_base_for_derived( derived_base_map, derived->in(1),maxlrg);
   uint i;
   for( i = 2; i < derived->req(); i++ )
     if( base != find_base_for_derived( derived_base_map,derived->in(i),maxlrg))
       break;
   // Went to the end without finding any different bases?
   if( i == derived->req() ) {   // No need for a base Phi here
     derived_base_map[derived->_idx] = base;
     return base;
   }
   // Now we see we need a base-Phi here to merge the bases
   const Type *t = base->bottom_type();
   base = new (C) PhiNode( derived->in(0), t );
   for( i = 1; i < derived->req(); i++ ) {
     base->init_req(i, find_base_for_derived(derived_base_map, derived->in(i), maxlrg));
     t = t->meet(base->in(i)->bottom_type());
   }
   base->as_Phi()->set_type(t);
   // Search the current block for an existing base-Phi
   Block *b = _cfg._bbs[derived->_idx];
   for( i = 1; i <= b->end_idx(); i++ ) {// Search for matching Phi
     Node *phi = b->_nodes[i];
     if( !phi->is_Phi() ) {      // Found end of Phis with no match?
       b->_nodes.insert( i, base ); // Must insert created Phi here as base
       _cfg._bbs.map( base->_idx, b );
       new_lrg(base,maxlrg++);
       break;
     }
     // See if Phi matches.
     uint j;
     for( j = 1; j < base->req(); j++ )
       if( phi->in(j) != base->in(j) &&
           !(phi->in(j)->is_Con() && base->in(j)->is_Con()) ) // allow different NULLs
         break;
     if( j == base->req() ) {    // All inputs match?
       base = phi;               // Then use existing 'phi' and drop 'base'
       break;
     }
   }
   // Cache info for later passes
   derived_base_map[derived->_idx] = base;
   return base;
 }
 //------------------------------stretch_base_pointer_live_ranges---------------
 // At each Safepoint, insert extra debug edges for each pair of derived value/
 // base pointer that is live across the Safepoint for oopmap building.  The
 // edge pairs get added in after sfpt->jvmtail()->oopoff(), but are in the
 // required edge set.
 bool PhaseChaitin::stretch_base_pointer_live_ranges(ResourceArea *a) {
   int must_recompute_live = false;
   uint maxlrg = _lrg_map.max_lrg_id();
   Node **derived_base_map = (Node**)a->Amalloc(sizeof(Node*)*C->unique());
   memset( derived_base_map, 0, sizeof(Node*)*C->unique() );
   // For all blocks in RPO do...
   for( uint i=0; i<_cfg._num_blocks; i++ ) {
     Block *b = _cfg._blocks[i];
     // Note use of deep-copy constructor.  I cannot hammer the original
     // liveout bits, because they are needed by the following coalesce pass.
     IndexSet liveout(_live->live(b));
     for( uint j = b->end_idx() + 1; j > 1; j-- ) {
       Node *n = b->_nodes[j-1];
       // Pre-split compares of loop-phis.  Loop-phis form a cycle we would
       // like to see in the same register.  Compare uses the loop-phi and so
       // extends its live range BUT cannot be part of the cycle.  If this
       // extended live range overlaps with the update of the loop-phi value
       // we need both alive at the same time -- which requires at least 1
       // copy.  But because Intel has only 2-address registers we end up with
       // at least 2 copies, one before the loop-phi update instruction and
       // one after.  Instead we split the input to the compare just after the
       // phi.
       if( n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_CmpI ) {
         Node *phi = n->in(1);
         if( phi->is_Phi() && phi->as_Phi()->region()->is_Loop() ) {
           Block *phi_block = _cfg._bbs[phi->_idx];
           if( _cfg._bbs[phi_block->pred(2)->_idx] == b ) {
             const RegMask *mask = C->matcher()->idealreg2spillmask[Op_RegI];
             Node *spill = new (C) MachSpillCopyNode( phi, *mask, *mask );
             insert_proj( phi_block, 1, spill, maxlrg++ );
             n->set_req(1,spill);
             must_recompute_live = true;
           }
         }
       }
       // Get value being defined
       uint lidx = _lrg_map.live_range_id(n);
       // Ignore the occasional brand-new live range
       if (lidx && lidx < _lrg_map.max_lrg_id()) {
         // Remove from live-out set
         liveout.remove(lidx);
         // Copies do not define a new value and so do not interfere.
         // Remove the copies source from the liveout set before interfering.
         uint idx = n->is_Copy();
         if (idx) {
           liveout.remove(_lrg_map.live_range_id(n->in(idx)));
         }
       }
       // Found a safepoint?
       JVMState *jvms = n->jvms();
       if( jvms ) {
         // Now scan for a live derived pointer
         IndexSetIterator elements(&liveout);
         uint neighbor;
         while ((neighbor = elements.next()) != 0) {
           // Find reaching DEF for base and derived values
           // This works because we are still in SSA during this call.
           Node *derived = lrgs(neighbor)._def;
           const TypePtr *tj = derived->bottom_type()->isa_ptr();
           assert(!derived->bottom_type()->isa_narrowoop() ||
                   derived->bottom_type()->make_ptr()->is_ptr()->_offset == 0, "sanity");
           // If its an OOP with a non-zero offset, then it is derived.
           if( tj && tj->_offset != 0 && tj->isa_oop_ptr() ) {
             Node *base = find_base_for_derived(derived_base_map, derived, maxlrg);
             assert(base->_idx < _lrg_map.size(), "");
             // Add reaching DEFs of derived pointer and base pointer as a
             // pair of inputs
             n->add_req(derived);
             n->add_req(base);
             // See if the base pointer is already live to this point.
             // Since I'm working on the SSA form, live-ness amounts to
             // reaching def's.  So if I find the base's live range then
             // I know the base's def reaches here.
             if ((_lrg_map.live_range_id(base) >= _lrg_map.max_lrg_id() || // (Brand new base (hence not live) or
                  !liveout.member(_lrg_map.live_range_id(base))) && // not live) AND
                  (_lrg_map.live_range_id(base) > 0) && // not a constant
                  _cfg._bbs[base->_idx] != b) { // base not def'd in blk)
               // Base pointer is not currently live.  Since I stretched
               // the base pointer to here and it crosses basic-block
               // boundaries, the global live info is now incorrect.
               // Recompute live.
               must_recompute_live = true;
             } // End of if base pointer is not live to debug info
           }
         } // End of scan all live data for derived ptrs crossing GC point
       } // End of if found a GC point
       // Make all inputs live
       if (!n->is_Phi()) {      // Phi function uses come from prior block
         for (uint k = 1; k < n->req(); k++) {
           uint lidx = _lrg_map.live_range_id(n->in(k));
           if (lidx < _lrg_map.max_lrg_id()) {
             liveout.insert(lidx);
           }
         }
       }
     } // End of forall instructions in block
     liveout.clear();  // Free the memory used by liveout.
   } // End of forall blocks
   _lrg_map.set_max_lrg_id(maxlrg);
   // If I created a new live range I need to recompute live
   if (maxlrg != _ifg->_maxlrg) {
     must_recompute_live = true;
   }
   return must_recompute_live != 0;
 }
 //------------------------------add_reference----------------------------------
 // Extend the node to LRG mapping
 void PhaseChaitin::add_reference(const Node *node, const Node *old_node) {
   _lrg_map.extend(node->_idx, _lrg_map.live_range_id(old_node));
 }
 //------------------------------dump-------------------------------------------
 #ifndef PRODUCT
 void PhaseChaitin::dump(const Node *n) const {
   uint r = (n->_idx < _lrg_map.size()) ? _lrg_map.find_const(n) : 0;
   tty->print("L%d",r);
   if (r && n->Opcode() != Op_Phi) {
     if( _node_regs ) {          // Got a post-allocation copy of allocation?
       tty->print("[");
       OptoReg::Name second = get_reg_second(n);
       if( OptoReg::is_valid(second) ) {
         if( OptoReg::is_reg(second) )
           tty->print("%s:",Matcher::regName[second]);
         else
           tty->print("%s+%d:",OptoReg::regname(OptoReg::c_frame_pointer), reg2offset_unchecked(second));
       }
       OptoReg::Name first = get_reg_first(n);
       if( OptoReg::is_reg(first) )
         tty->print("%s]",Matcher::regName[first]);
       else
          tty->print("%s+%d]",OptoReg::regname(OptoReg::c_frame_pointer), reg2offset_unchecked(first));
     } else
     n->out_RegMask().dump();
   }
   tty->print("/N%d\t",n->_idx);
   tty->print("%s === ", n->Name());
   uint k;
   for (k = 0; k < n->req(); k++) {
     Node *m = n->in(k);
     if (!m) {
       tty->print("_ ");
     }
     else {
       uint r = (m->_idx < _lrg_map.size()) ? _lrg_map.find_const(m) : 0;
       tty->print("L%d",r);
       // Data MultiNode's can have projections with no real registers.
       // Don't die while dumping them.
       int op = n->Opcode();
       if( r && op != Op_Phi && op != Op_Proj && op != Op_SCMemProj) {
         if( _node_regs ) {
           tty->print("[");
           OptoReg::Name second = get_reg_second(n->in(k));
           if( OptoReg::is_valid(second) ) {
             if( OptoReg::is_reg(second) )
               tty->print("%s:",Matcher::regName[second]);
             else
               tty->print("%s+%d:",OptoReg::regname(OptoReg::c_frame_pointer),
                          reg2offset_unchecked(second));
           }
           OptoReg::Name first = get_reg_first(n->in(k));
           if( OptoReg::is_reg(first) )
             tty->print("%s]",Matcher::regName[first]);
           else
             tty->print("%s+%d]",OptoReg::regname(OptoReg::c_frame_pointer),
                        reg2offset_unchecked(first));
         } else
           n->in_RegMask(k).dump();
       }
       tty->print("/N%d ",m->_idx);
     }
   }
   if( k < n->len() && n->in(k) ) tty->print("| ");
   for( ; k < n->len(); k++ ) {
     Node *m = n->in(k);
     if(!m) {
       break;
     }
     uint r = (m->_idx < _lrg_map.size()) ? _lrg_map.find_const(m) : 0;
     tty->print("L%d",r);
     tty->print("/N%d ",m->_idx);
   }
   if( n->is_Mach() ) n->as_Mach()->dump_spec(tty);
   else n->dump_spec(tty);
   if( _spilled_once.test(n->_idx ) ) {
     tty->print(" Spill_1");
     if( _spilled_twice.test(n->_idx ) )
       tty->print(" Spill_2");
   }
   tty->print("\n");
 }
 void PhaseChaitin::dump( const Block * b ) const {
   b->dump_head( &_cfg._bbs );
   // For all instructions
   for( uint j = 0; j < b->_nodes.size(); j++ )
     dump(b->_nodes[j]);
   // Print live-out info at end of block
   if( _live ) {
     tty->print("Liveout: ");
     IndexSet *live = _live->live(b);
     IndexSetIterator elements(live);
     tty->print("{");
     uint i;
     while ((i = elements.next()) != 0) {
       tty->print("L%d ", _lrg_map.find_const(i));
     }
     tty->print_cr("}");
   }
   tty->print("\n");
 }
 void PhaseChaitin::dump() const {
   tty->print( "--- Chaitin -- argsize: %d  framesize: %d ---\n",
               _matcher._new_SP, _framesize );
   // For all blocks
   for( uint i = 0; i < _cfg._num_blocks; i++ )
     dump(_cfg._blocks[i]);
   // End of per-block dump
   tty->print("\n");
   if (!_ifg) {
     tty->print("(No IFG.)\n");
     return;
   }
   // Dump LRG array
   tty->print("--- Live RanGe Array ---\n");
   for (uint i2 = 1; i2 < _lrg_map.max_lrg_id(); i2++) {
     tty->print("L%d: ",i2);
     if (i2 < _ifg->_maxlrg) {
       lrgs(i2).dump();
     }
     else {
       tty->print_cr("new LRG");
     }
   }
   tty->print_cr("");
   // Dump lo-degree list
   tty->print("Lo degree: ");
   for(uint i3 = _lo_degree; i3; i3 = lrgs(i3)._next )
     tty->print("L%d ",i3);
   tty->print_cr("");
   // Dump lo-stk-degree list
   tty->print("Lo stk degree: ");
   for(uint i4 = _lo_stk_degree; i4; i4 = lrgs(i4)._next )
     tty->print("L%d ",i4);
   tty->print_cr("");
   // Dump lo-degree list
   tty->print("Hi degree: ");
   for(uint i5 = _hi_degree; i5; i5 = lrgs(i5)._next )
     tty->print("L%d ",i5);
   tty->print_cr("");
 }
 //------------------------------dump_degree_lists------------------------------
 void PhaseChaitin::dump_degree_lists() const {
   // Dump lo-degree list
   tty->print("Lo degree: ");
   for( uint i = _lo_degree; i; i = lrgs(i)._next )
     tty->print("L%d ",i);
   tty->print_cr("");
   // Dump lo-stk-degree list
   tty->print("Lo stk degree: ");
   for(uint i2 = _lo_stk_degree; i2; i2 = lrgs(i2)._next )
     tty->print("L%d ",i2);
   tty->print_cr("");
   // Dump lo-degree list
   tty->print("Hi degree: ");
   for(uint i3 = _hi_degree; i3; i3 = lrgs(i3)._next )
     tty->print("L%d ",i3);
   tty->print_cr("");
 }
 //------------------------------dump_simplified--------------------------------
 void PhaseChaitin::dump_simplified() const {
   tty->print("Simplified: ");
   for( uint i = _simplified; i; i = lrgs(i)._next )
     tty->print("L%d ",i);
   tty->print_cr("");
 }
 static char *print_reg( OptoReg::Name reg, const PhaseChaitin *pc, char *buf ) {
   if ((int)reg < 0)
     sprintf(buf, "<OptoReg::%d>", (int)reg);
   else if (OptoReg::is_reg(reg))
     strcpy(buf, Matcher::regName[reg]);
   else
     sprintf(buf,"%s + #%d",OptoReg::regname(OptoReg::c_frame_pointer),
             pc->reg2offset(reg));
   return buf+strlen(buf);
 }
 //------------------------------dump_register----------------------------------
 // Dump a register name into a buffer.  Be intelligent if we get called
 // before allocation is complete.
 char *PhaseChaitin::dump_register( const Node *n, char *buf  ) const {
   if( !this ) {                 // Not got anything?
     sprintf(buf,"N%d",n->_idx); // Then use Node index
   } else if( _node_regs ) {
     // Post allocation, use direct mappings, no LRG info available
     print_reg( get_reg_first(n), this, buf );
   } else {
     uint lidx = _lrg_map.find_const(n); // Grab LRG number
     if( !_ifg ) {
       sprintf(buf,"L%d",lidx);  // No register binding yet
     } else if( !lidx ) {        // Special, not allocated value
       strcpy(buf,"Special");
     } else {
       if (lrgs(lidx)._is_vector) {
         if (lrgs(lidx).mask().is_bound_set(lrgs(lidx).num_regs()))
           print_reg( lrgs(lidx).reg(), this, buf ); // a bound machine register
         else
           sprintf(buf,"L%d",lidx); // No register binding yet
       } else if( (lrgs(lidx).num_regs() == 1)
                  ? lrgs(lidx).mask().is_bound1()
                  : lrgs(lidx).mask().is_bound_pair() ) {
         // Hah!  We have a bound machine register
         print_reg( lrgs(lidx).reg(), this, buf );
       } else {
         sprintf(buf,"L%d",lidx); // No register binding yet
       }
     }
   }
   return buf+strlen(buf);
 }
 //----------------------dump_for_spill_split_recycle--------------------------
 void PhaseChaitin::dump_for_spill_split_recycle() const {
   if( WizardMode && (PrintCompilation || PrintOpto) ) {
     // Display which live ranges need to be split and the allocator's state
     tty->print_cr("Graph-Coloring Iteration %d will split the following live ranges", _trip_cnt);
     for (uint bidx = 1; bidx < _lrg_map.max_lrg_id(); bidx++) {
       if( lrgs(bidx).alive() && lrgs(bidx).reg() >= LRG::SPILL_REG ) {
         tty->print("L%d: ", bidx);
         lrgs(bidx).dump();
       }
     }
     tty->cr();
     dump();
   }
 }
 //------------------------------dump_frame------------------------------------
 void PhaseChaitin::dump_frame() const {
   const char *fp = OptoReg::regname(OptoReg::c_frame_pointer);
   const TypeTuple *domain = C->tf()->domain();
   const int        argcnt = domain->cnt() - TypeFunc::Parms;
   // Incoming arguments in registers dump
   for( int k = 0; k < argcnt; k++ ) {
     OptoReg::Name parmreg = _matcher._parm_regs[k].first();
     if( OptoReg::is_reg(parmreg))  {
       const char *reg_name = OptoReg::regname(parmreg);
       tty->print("#r%3.3d %s", parmreg, reg_name);
       parmreg = _matcher._parm_regs[k].second();
       if( OptoReg::is_reg(parmreg))  {
         tty->print(":%s", OptoReg::regname(parmreg));
       }
       tty->print("   : parm %d: ", k);
       domain->field_at(k + TypeFunc::Parms)->dump();
       tty->print_cr("");
     }
   }
   // Check for un-owned padding above incoming args
   OptoReg::Name reg = _matcher._new_SP;
   if( reg > _matcher._in_arg_limit ) {
     reg = OptoReg::add(reg, -1);
     tty->print_cr("#r%3.3d %s+%2d: pad0, owned by CALLER", reg, fp, reg2offset_unchecked(reg));
   }
   // Incoming argument area dump
   OptoReg::Name begin_in_arg = OptoReg::add(_matcher._old_SP,C->out_preserve_stack_slots());
   while( reg > begin_in_arg ) {
     reg = OptoReg::add(reg, -1);
     tty->print("#r%3.3d %s+%2d: ",reg,fp,reg2offset_unchecked(reg));
     int j;
     for( j = 0; j < argcnt; j++) {
       if( _matcher._parm_regs[j].first() == reg ||
           _matcher._parm_regs[j].second() == reg ) {
         tty->print("parm %d: ",j);
         domain->field_at(j + TypeFunc::Parms)->dump();
         tty->print_cr("");
         break;
       }
     }
     if( j >= argcnt )
       tty->print_cr("HOLE, owned by SELF");
   }
   // Old outgoing preserve area
   while( reg > _matcher._old_SP ) {
     reg = OptoReg::add(reg, -1);
     tty->print_cr("#r%3.3d %s+%2d: old out preserve",reg,fp,reg2offset_unchecked(reg));
   }
   // Old SP
   tty->print_cr("# -- Old %s -- Framesize: %d --",fp,
     reg2offset_unchecked(OptoReg::add(_matcher._old_SP,-1)) - reg2offset_unchecked(_matcher._new_SP)+jintSize);
   // Preserve area dump
   int fixed_slots = C->fixed_slots();
   OptoReg::Name begin_in_preserve = OptoReg::add(_matcher._old_SP, -(int)C->in_preserve_stack_slots());
   OptoReg::Name return_addr = _matcher.return_addr();
   reg = OptoReg::add(reg, -1);
   while (OptoReg::is_stack(reg)) {
     tty->print("#r%3.3d %s+%2d: ",reg,fp,reg2offset_unchecked(reg));
     if (return_addr == reg) {
       tty->print_cr("return address");
     } else if (reg >= begin_in_preserve) {
       // Preserved slots are present on x86
       if (return_addr == OptoReg::add(reg, VMRegImpl::slots_per_word))
         tty->print_cr("saved fp register");
       else if (return_addr == OptoReg::add(reg, 2*VMRegImpl::slots_per_word) &&
                VerifyStackAtCalls)
         tty->print_cr("0xBADB100D   +VerifyStackAtCalls");
       else
         tty->print_cr("in_preserve");
     } else if ((int)OptoReg::reg2stack(reg) < fixed_slots) {
       tty->print_cr("Fixed slot %d", OptoReg::reg2stack(reg));
     } else {
       tty->print_cr("pad2, stack alignment");
     }
     reg = OptoReg::add(reg, -1);
   }
   // Spill area dump
   reg = OptoReg::add(_matcher._new_SP, _framesize );
   while( reg > _matcher._out_arg_limit ) {
     reg = OptoReg::add(reg, -1);
     tty->print_cr("#r%3.3d %s+%2d: spill",reg,fp,reg2offset_unchecked(reg));
   }
   // Outgoing argument area dump
   while( reg > OptoReg::add(_matcher._new_SP, C->out_preserve_stack_slots()) ) {
     reg = OptoReg::add(reg, -1);
     tty->print_cr("#r%3.3d %s+%2d: outgoing argument",reg,fp,reg2offset_unchecked(reg));
   }
   // Outgoing new preserve area
   while( reg > _matcher._new_SP ) {
     reg = OptoReg::add(reg, -1);
     tty->print_cr("#r%3.3d %s+%2d: new out preserve",reg,fp,reg2offset_unchecked(reg));
   }
   tty->print_cr("#");
 }
 //------------------------------dump_bb----------------------------------------
 void PhaseChaitin::dump_bb( uint pre_order ) const {
   tty->print_cr("---dump of B%d---",pre_order);
   for( uint i = 0; i < _cfg._num_blocks; i++ ) {
     Block *b = _cfg._blocks[i];
     if( b->_pre_order == pre_order )
       dump(b);
   }
 }
 //------------------------------dump_lrg---------------------------------------
 void PhaseChaitin::dump_lrg( uint lidx, bool defs_only ) const {
   tty->print_cr("---dump of L%d---",lidx);
   if (_ifg) {
     if (lidx >= _lrg_map.max_lrg_id()) {
       tty->print("Attempt to print live range index beyond max live range.\n");
       return;
     }
     tty->print("L%d: ",lidx);
     if (lidx < _ifg->_maxlrg) {
       lrgs(lidx).dump();
     } else {
       tty->print_cr("new LRG");
     }
   }
   if( _ifg && lidx < _ifg->_maxlrg) {
     tty->print("Neighbors: %d - ", _ifg->neighbor_cnt(lidx));
     _ifg->neighbors(lidx)->dump();
     tty->cr();
   }
   // For all blocks
   for( uint i = 0; i < _cfg._num_blocks; i++ ) {
     Block *b = _cfg._blocks[i];
     int dump_once = 0;
     // For all instructions
     for( uint j = 0; j < b->_nodes.size(); j++ ) {
       Node *n = b->_nodes[j];
       if (_lrg_map.find_const(n) == lidx) {
         if (!dump_once++) {
           tty->cr();
           b->dump_head( &_cfg._bbs );
         }
         dump(n);
         continue;
       }
       if (!defs_only) {
         uint cnt = n->req();
         for( uint k = 1; k < cnt; k++ ) {
           Node *m = n->in(k);
           if (!m)  {
             continue;  // be robust in the dumper
           }
           if (_lrg_map.find_const(m) == lidx) {
             if (!dump_once++) {
               tty->cr();
               b->dump_head(&_cfg._bbs);
             }
             dump(n);
           }
         }
       }
     }
   } // End of per-block dump
   tty->cr();
 }
 #endif // not PRODUCT
 //------------------------------print_chaitin_statistics-------------------------------
 int PhaseChaitin::_final_loads  = 0;
 int PhaseChaitin::_final_stores = 0;
 int PhaseChaitin::_final_memoves= 0;
 int PhaseChaitin::_final_copies = 0;
 double PhaseChaitin::_final_load_cost  = 0;
 double PhaseChaitin::_final_store_cost = 0;
 double PhaseChaitin::_final_memove_cost= 0;
 double PhaseChaitin::_final_copy_cost  = 0;
 int PhaseChaitin::_conserv_coalesce = 0;
 int PhaseChaitin::_conserv_coalesce_pair = 0;
 int PhaseChaitin::_conserv_coalesce_trie = 0;
 int PhaseChaitin::_conserv_coalesce_quad = 0;
 int PhaseChaitin::_post_alloc = 0;
 int PhaseChaitin::_lost_opp_pp_coalesce = 0;
 int PhaseChaitin::_lost_opp_cflow_coalesce = 0;
 int PhaseChaitin::_used_cisc_instructions   = 0;
 int PhaseChaitin::_unused_cisc_instructions = 0;
 int PhaseChaitin::_allocator_attempts       = 0;
 int PhaseChaitin::_allocator_successes      = 0;
 #ifndef PRODUCT
 uint PhaseChaitin::_high_pressure           = 0;
 uint PhaseChaitin::_low_pressure            = 0;
 void PhaseChaitin::print_chaitin_statistics() {
   tty->print_cr("Inserted %d spill loads, %d spill stores, %d mem-mem moves and %d copies.", _final_loads, _final_stores, _final_memoves, _final_copies);
   tty->print_cr("Total load cost= %6.0f, store cost = %6.0f, mem-mem cost = %5.2f, copy cost = %5.0f.", _final_load_cost, _final_store_cost, _final_memove_cost, _final_copy_cost);
   tty->print_cr("Adjusted spill cost = %7.0f.",
                 _final_load_cost*4.0 + _final_store_cost  * 2.0 +
                 _final_copy_cost*1.0 + _final_memove_cost*12.0);
   tty->print("Conservatively coalesced %d copies, %d pairs",
                 _conserv_coalesce, _conserv_coalesce_pair);
   if( _conserv_coalesce_trie || _conserv_coalesce_quad )
     tty->print(", %d tries, %d quads", _conserv_coalesce_trie, _conserv_coalesce_quad);
   tty->print_cr(", %d post alloc.", _post_alloc);
   if( _lost_opp_pp_coalesce || _lost_opp_cflow_coalesce )
     tty->print_cr("Lost coalesce opportunity, %d private-private, and %d cflow interfered.",
                   _lost_opp_pp_coalesce, _lost_opp_cflow_coalesce );
   if( _used_cisc_instructions || _unused_cisc_instructions )
     tty->print_cr("Used cisc instruction  %d,  remained in register %d",
                    _used_cisc_instructions, _unused_cisc_instructions);
   if( _allocator_successes != 0 )
     tty->print_cr("Average allocation trips %f", (float)_allocator_attempts/(float)_allocator_successes);
   tty->print_cr("High Pressure Blocks = %d, Low Pressure Blocks = %d", _high_pressure, _low_pressure);
 }
 #endif // not PRODUCT

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/opto/chaitin.cpp@ef57c43512d6 (annotated)

src/share/vm/opto/chaitin.cpp