Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1998, 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 "ci/ciMethodData.hpp"

 #include "classfile/systemDictionary.hpp"

 #include "classfile/vmSymbols.hpp"

 #include "compiler/compileLog.hpp"

 #include "interpreter/linkResolver.hpp"

 #include "memory/universe.inline.hpp"

 #include "opto/addnode.hpp"

 #include "opto/divnode.hpp"

 #include "opto/idealGraphPrinter.hpp"

 #include "opto/matcher.hpp"

 #include "opto/memnode.hpp"

 #include "opto/mulnode.hpp"

 #include "opto/parse.hpp"

 #include "opto/runtime.hpp"

 #include "runtime/deoptimization.hpp"

 #include "runtime/sharedRuntime.hpp"

 extern int explicit_null_checks_inserted,

            explicit_null_checks_elided;

 //---------------------------------array_load----------------------------------

 void Parse::array_load(BasicType elem_type) {

   const Type* elem = Type::TOP;

   Node* adr = array_addressing(elem_type, 0, &elem);

   if (stopped())  return;     // guaranteed null or range check

   dec_sp(2);                  // Pop array and index

   const TypeAryPtr* adr_type = TypeAryPtr::get_array_body_type(elem_type);

   Node* ld = make_load(control(), adr, elem, elem_type, adr_type);

   push(ld);

 }

 //--------------------------------array_store----------------------------------

 void Parse::array_store(BasicType elem_type) {

   Node* adr = array_addressing(elem_type, 1);

   if (stopped())  return;     // guaranteed null or range check

   Node* val = pop();

   dec_sp(2);                  // Pop array and index

   const TypeAryPtr* adr_type = TypeAryPtr::get_array_body_type(elem_type);

   store_to_memory(control(), adr, val, elem_type, adr_type);

 }

 //------------------------------array_addressing-------------------------------

 // Pull array and index from the stack.  Compute pointer-to-element.

 Node* Parse::array_addressing(BasicType type, int vals, const Type* *result2) {

   Node *idx   = peek(0+vals);   // Get from stack without popping

   Node *ary   = peek(1+vals);   // in case of exception

   // Null check the array base, with correct stack contents

   ary = null_check(ary, T_ARRAY);

   // Compile-time detect of null-exception?

   if (stopped())  return top();

   const TypeAryPtr* arytype  = _gvn.type(ary)->is_aryptr();

   const TypeInt*    sizetype = arytype->size();

   const Type*       elemtype = arytype->elem();

   if (UseUniqueSubclasses && result2 != NULL) {

     const Type* el = elemtype->make_ptr();

     if (el && el->isa_instptr()) {

       const TypeInstPtr* toop = el->is_instptr();

       if (toop->klass()->as_instance_klass()->unique_concrete_subklass()) {

         // If we load from "AbstractClass[]" we must see "ConcreteSubClass".

         const Type* subklass = Type::get_const_type(toop->klass());

         elemtype = subklass->join(el);

       }

     }

   }

   // Check for big class initializers with all constant offsets

   // feeding into a known-size array.

   const TypeInt* idxtype = _gvn.type(idx)->is_int();

   // See if the highest idx value is less than the lowest array bound,

   // and if the idx value cannot be negative:

   bool need_range_check = true;

   if (idxtype->_hi < sizetype->_lo && idxtype->_lo >= 0) {

     need_range_check = false;

     if (C->log() != NULL)   C->log()->elem("observe that='!need_range_check'");

   }

   ciKlass * arytype_klass = arytype->klass();

   if ((arytype_klass != NULL) && (!arytype_klass->is_loaded())) {

     // Only fails for some -Xcomp runs

     // The class is unloaded.  We have to run this bytecode in the interpreter.

     uncommon_trap(Deoptimization::Reason_unloaded,

                   Deoptimization::Action_reinterpret,

                   arytype->klass(), "!loaded array");

     return top();

   }

   // Do the range check

   if (GenerateRangeChecks && need_range_check) {

     Node* tst;

     if (sizetype->_hi <= 0) {

       // The greatest array bound is negative, so we can conclude that we're

       // compiling unreachable code, but the unsigned compare trick used below

       // only works with non-negative lengths.  Instead, hack "tst" to be zero so

       // the uncommon_trap path will always be taken.

       tst = _gvn.intcon(0);

     } else {

       // Range is constant in array-oop, so we can use the original state of mem

       Node* len = load_array_length(ary);

       // Test length vs index (standard trick using unsigned compare)

       Node* chk = _gvn.transform( new (C) CmpUNode(idx, len) );

       BoolTest::mask btest = BoolTest::lt;

       tst = _gvn.transform( new (C) BoolNode(chk, btest) );

     }

     // Branch to failure if out of bounds

     { BuildCutout unless(this, tst, PROB_MAX);

       if (C->allow_range_check_smearing()) {

         // Do not use builtin_throw, since range checks are sometimes

         // made more stringent by an optimistic transformation.

         // This creates "tentative" range checks at this point,

         // which are not guaranteed to throw exceptions.

         // See IfNode::Ideal, is_range_check, adjust_check.

         uncommon_trap(Deoptimization::Reason_range_check,

                       Deoptimization::Action_make_not_entrant,

                       NULL, "range_check");

       } else {

         // If we have already recompiled with the range-check-widening

         // heroic optimization turned off, then we must really be throwing

         // range check exceptions.

         builtin_throw(Deoptimization::Reason_range_check, idx);

       }

     }

   }

   // Check for always knowing you are throwing a range-check exception

   if (stopped())  return top();

   Node* ptr = array_element_address(ary, idx, type, sizetype);

   if (result2 != NULL)  *result2 = elemtype;

   assert(ptr != top(), "top should go hand-in-hand with stopped");

   return ptr;

 }

 // returns IfNode

 IfNode* Parse::jump_if_fork_int(Node* a, Node* b, BoolTest::mask mask) {

   Node   *cmp = _gvn.transform( new (C) CmpINode( a, b)); // two cases: shiftcount > 32 and shiftcount <= 32

   Node   *tst = _gvn.transform( new (C) BoolNode( cmp, mask));

   IfNode *iff = create_and_map_if( control(), tst, ((mask == BoolTest::eq) ? PROB_STATIC_INFREQUENT : PROB_FAIR), COUNT_UNKNOWN );

   return iff;

 }

 // return Region node

 Node* Parse::jump_if_join(Node* iffalse, Node* iftrue) {

   Node *region  = new (C) RegionNode(3); // 2 results

   record_for_igvn(region);

   region->init_req(1, iffalse);

   region->init_req(2, iftrue );

   _gvn.set_type(region, Type::CONTROL);

   region = _gvn.transform(region);

   set_control (region);

   return region;

 }

 //------------------------------helper for tableswitch-------------------------

 void Parse::jump_if_true_fork(IfNode *iff, int dest_bci_if_true, int prof_table_index) {

   // True branch, use existing map info

   { PreserveJVMState pjvms(this);

     Node *iftrue  = _gvn.transform( new (C) IfTrueNode (iff) );

     set_control( iftrue );

     profile_switch_case(prof_table_index);

     merge_new_path(dest_bci_if_true);

   }

   // False branch

   Node *iffalse = _gvn.transform( new (C) IfFalseNode(iff) );

   set_control( iffalse );

 }

 void Parse::jump_if_false_fork(IfNode *iff, int dest_bci_if_true, int prof_table_index) {

   // True branch, use existing map info

   { PreserveJVMState pjvms(this);

     Node *iffalse  = _gvn.transform( new (C) IfFalseNode (iff) );

     set_control( iffalse );

     profile_switch_case(prof_table_index);

     merge_new_path(dest_bci_if_true);

   }

   // False branch

   Node *iftrue = _gvn.transform( new (C) IfTrueNode(iff) );

   set_control( iftrue );

 }

 void Parse::jump_if_always_fork(int dest_bci, int prof_table_index) {

   // False branch, use existing map and control()

   profile_switch_case(prof_table_index);

   merge_new_path(dest_bci);

 }

 extern "C" {

   static int jint_cmp(const void *i, const void *j) {

     int a = *(jint *)i;

     int b = *(jint *)j;

     return a > b ? 1 : a < b ? -1 : 0;

   }

 }

 // Default value for methodData switch indexing. Must be a negative value to avoid

 // conflict with any legal switch index.

 #define NullTableIndex -1

 class SwitchRange : public StackObj {

   // a range of integers coupled with a bci destination

   jint _lo;                     // inclusive lower limit

   jint _hi;                     // inclusive upper limit

   int _dest;

   int _table_index;             // index into method data table

 public:

   jint lo() const              { return _lo;   }

   jint hi() const              { return _hi;   }

   int  dest() const            { return _dest; }

   int  table_index() const     { return _table_index; }

   bool is_singleton() const    { return _lo == _hi; }

   void setRange(jint lo, jint hi, int dest, int table_index) {

     assert(lo <= hi, "must be a non-empty range");

     _lo = lo, _hi = hi; _dest = dest; _table_index = table_index;

   }

   bool adjoinRange(jint lo, jint hi, int dest, int table_index) {

     assert(lo <= hi, "must be a non-empty range");

     if (lo == _hi+1 && dest == _dest && table_index == _table_index) {

       _hi = hi;

       return true;

     }

     return false;

   }

   void set (jint value, int dest, int table_index) {

     setRange(value, value, dest, table_index);

   }

   bool adjoin(jint value, int dest, int table_index) {

     return adjoinRange(value, value, dest, table_index);

   }

   void print(ciEnv* env) {

     if (is_singleton())

       tty->print(" {%d}=>%d", lo(), dest());

     else if (lo() == min_jint)

       tty->print(" {..%d}=>%d", hi(), dest());

     else if (hi() == max_jint)

       tty->print(" {%d..}=>%d", lo(), dest());

     else

       tty->print(" {%d..%d}=>%d", lo(), hi(), dest());

   }

 };

 //-------------------------------do_tableswitch--------------------------------

 void Parse::do_tableswitch() {

   Node* lookup = pop();

   // Get information about tableswitch

   int default_dest = iter().get_dest_table(0);

   int lo_index     = iter().get_int_table(1);

   int hi_index     = iter().get_int_table(2);

   int len          = hi_index - lo_index + 1;

   if (len < 1) {

     // If this is a backward branch, add safepoint

     maybe_add_safepoint(default_dest);

     merge(default_dest);

     return;

   }

   // generate decision tree, using trichotomy when possible

   int rnum = len+2;

   bool makes_backward_branch = false;

   SwitchRange* ranges = NEW_RESOURCE_ARRAY(SwitchRange, rnum);

   int rp = -1;

   if (lo_index != min_jint) {

     ranges[++rp].setRange(min_jint, lo_index-1, default_dest, NullTableIndex);

   }

   for (int j = 0; j < len; j++) {

     jint match_int = lo_index+j;

     int  dest      = iter().get_dest_table(j+3);

     makes_backward_branch |= (dest <= bci());

     int  table_index = method_data_update() ? j : NullTableIndex;

     if (rp < 0 || !ranges[rp].adjoin(match_int, dest, table_index)) {

       ranges[++rp].set(match_int, dest, table_index);

     }

   }

   jint highest = lo_index+(len-1);

   assert(ranges[rp].hi() == highest, "");

   if (highest != max_jint

       && !ranges[rp].adjoinRange(highest+1, max_jint, default_dest, NullTableIndex)) {

     ranges[++rp].setRange(highest+1, max_jint, default_dest, NullTableIndex);

   }

   assert(rp < len+2, "not too many ranges");

   // Safepoint in case if backward branch observed

   if( makes_backward_branch && UseLoopSafepoints )

     add_safepoint();

   jump_switch_ranges(lookup, &ranges[0], &ranges[rp]);

 }

 //------------------------------do_lookupswitch--------------------------------

 void Parse::do_lookupswitch() {

   Node *lookup = pop();         // lookup value

   // Get information about lookupswitch

   int default_dest = iter().get_dest_table(0);

   int len          = iter().get_int_table(1);

   if (len < 1) {    // If this is a backward branch, add safepoint

     maybe_add_safepoint(default_dest);

     merge(default_dest);

     return;

   }

   // generate decision tree, using trichotomy when possible

   jint* table = NEW_RESOURCE_ARRAY(jint, len*2);

   {

     for( int j = 0; j < len; j++ ) {

       table[j+j+0] = iter().get_int_table(2+j+j);

       table[j+j+1] = iter().get_dest_table(2+j+j+1);

     }

     qsort( table, len, 2*sizeof(table[0]), jint_cmp );

   }

   int rnum = len*2+1;

   bool makes_backward_branch = false;

   SwitchRange* ranges = NEW_RESOURCE_ARRAY(SwitchRange, rnum);

   int rp = -1;

   for( int j = 0; j < len; j++ ) {

     jint match_int   = table[j+j+0];

     int  dest        = table[j+j+1];

     int  next_lo     = rp < 0 ? min_jint : ranges[rp].hi()+1;

     int  table_index = method_data_update() ? j : NullTableIndex;

     makes_backward_branch |= (dest <= bci());

     if( match_int != next_lo ) {

       ranges[++rp].setRange(next_lo, match_int-1, default_dest, NullTableIndex);

     }

     if( rp < 0 || !ranges[rp].adjoin(match_int, dest, table_index) ) {

       ranges[++rp].set(match_int, dest, table_index);

     }

   }

   jint highest = table[2*(len-1)];

   assert(ranges[rp].hi() == highest, "");

   if( highest != max_jint

       && !ranges[rp].adjoinRange(highest+1, max_jint, default_dest, NullTableIndex) ) {

     ranges[++rp].setRange(highest+1, max_jint, default_dest, NullTableIndex);

   }

   assert(rp < rnum, "not too many ranges");

   // Safepoint in case backward branch observed

   if( makes_backward_branch && UseLoopSafepoints )

     add_safepoint();

   jump_switch_ranges(lookup, &ranges[0], &ranges[rp]);

 }

 //----------------------------create_jump_tables-------------------------------

 bool Parse::create_jump_tables(Node* key_val, SwitchRange* lo, SwitchRange* hi) {

   // Are jumptables enabled

   if (!UseJumpTables)  return false;

   // Are jumptables supported

   if (!Matcher::has_match_rule(Op_Jump))  return false;

   // Don't make jump table if profiling

   if (method_data_update())  return false;

   // Decide if a guard is needed to lop off big ranges at either (or

   // both) end(s) of the input set. We'll call this the default target

   // even though we can't be sure that it is the true "default".

   bool needs_guard = false;

   int default_dest;

   int64 total_outlier_size = 0;

   int64 hi_size = ((int64)hi->hi()) - ((int64)hi->lo()) + 1;

   int64 lo_size = ((int64)lo->hi()) - ((int64)lo->lo()) + 1;

   if (lo->dest() == hi->dest()) {

     total_outlier_size = hi_size + lo_size;

     default_dest = lo->dest();

   } else if (lo_size > hi_size) {

     total_outlier_size = lo_size;

     default_dest = lo->dest();

   } else {

     total_outlier_size = hi_size;

     default_dest = hi->dest();

   }

   // If a guard test will eliminate very sparse end ranges, then

   // it is worth the cost of an extra jump.

   if (total_outlier_size > (MaxJumpTableSparseness * 4)) {

     needs_guard = true;

     if (default_dest == lo->dest()) lo++;

     if (default_dest == hi->dest()) hi--;

   }

   // Find the total number of cases and ranges

   int64 num_cases = ((int64)hi->hi()) - ((int64)lo->lo()) + 1;

   int num_range = hi - lo + 1;

   // Don't create table if: too large, too small, or too sparse.

   if (num_cases < MinJumpTableSize || num_cases > MaxJumpTableSize)

     return false;

   if (num_cases > (MaxJumpTableSparseness * num_range))

     return false;

   // Normalize table lookups to zero

   int lowval = lo->lo();

   key_val = _gvn.transform( new (C) SubINode(key_val, _gvn.intcon(lowval)) );

   // Generate a guard to protect against input keyvals that aren't

   // in the switch domain.

   if (needs_guard) {

     Node*   size = _gvn.intcon(num_cases);

     Node*   cmp = _gvn.transform( new (C) CmpUNode(key_val, size) );

     Node*   tst = _gvn.transform( new (C) BoolNode(cmp, BoolTest::ge) );

     IfNode* iff = create_and_map_if( control(), tst, PROB_FAIR, COUNT_UNKNOWN);

     jump_if_true_fork(iff, default_dest, NullTableIndex);

   }

   // Create an ideal node JumpTable that has projections

   // of all possible ranges for a switch statement

   // The key_val input must be converted to a pointer offset and scaled.

   // Compare Parse::array_addressing above.

 #ifdef _LP64

   // Clean the 32-bit int into a real 64-bit offset.

   // Otherwise, the jint value 0 might turn into an offset of 0x0800000000.

   const TypeLong* lkeytype = TypeLong::make(CONST64(0), num_cases-1, Type::WidenMin);

   key_val       = _gvn.transform( new (C) ConvI2LNode(key_val, lkeytype) );

 #endif

   // Shift the value by wordsize so we have an index into the table, rather

   // than a switch value

   Node *shiftWord = _gvn.MakeConX(wordSize);

   key_val = _gvn.transform( new (C) MulXNode( key_val, shiftWord));

   // Create the JumpNode

   Node* jtn = _gvn.transform( new (C) JumpNode(control(), key_val, num_cases) );

   // These are the switch destinations hanging off the jumpnode

   int i = 0;

   for (SwitchRange* r = lo; r <= hi; r++) {

     for (int j = r->lo(); j <= r->hi(); j++, i++) {

       Node* input = _gvn.transform(new (C) JumpProjNode(jtn, i, r->dest(), j - lowval));

       {

         PreserveJVMState pjvms(this);

         set_control(input);

         jump_if_always_fork(r->dest(), r->table_index());

       }

     }

   }

   assert(i == num_cases, "miscount of cases");

   stop_and_kill_map();  // no more uses for this JVMS

   return true;

 }

 //----------------------------jump_switch_ranges-------------------------------

 void Parse::jump_switch_ranges(Node* key_val, SwitchRange *lo, SwitchRange *hi, int switch_depth) {

   Block* switch_block = block();

   if (switch_depth == 0) {

     // Do special processing for the top-level call.

     assert(lo->lo() == min_jint, "initial range must exhaust Type::INT");

     assert(hi->hi() == max_jint, "initial range must exhaust Type::INT");

     // Decrement pred-numbers for the unique set of nodes.

 #ifdef ASSERT

     // Ensure that the block's successors are a (duplicate-free) set.

     int successors_counted = 0;  // block occurrences in [hi..lo]

     int unique_successors = switch_block->num_successors();

     for (int i = 0; i < unique_successors; i++) {

       Block* target = switch_block->successor_at(i);

       // Check that the set of successors is the same in both places.

       int successors_found = 0;

       for (SwitchRange* p = lo; p <= hi; p++) {

         if (p->dest() == target->start())  successors_found++;

       }

       assert(successors_found > 0, "successor must be known");

       successors_counted += successors_found;

     }

     assert(successors_counted == (hi-lo)+1, "no unexpected successors");

 #endif

     // Maybe prune the inputs, based on the type of key_val.

     jint min_val = min_jint;

     jint max_val = max_jint;

     const TypeInt* ti = key_val->bottom_type()->isa_int();

     if (ti != NULL) {

       min_val = ti->_lo;

       max_val = ti->_hi;

       assert(min_val <= max_val, "invalid int type");

     }

     while (lo->hi() < min_val)  lo++;

     if (lo->lo() < min_val)  lo->setRange(min_val, lo->hi(), lo->dest(), lo->table_index());

     while (hi->lo() > max_val)  hi--;

     if (hi->hi() > max_val)  hi->setRange(hi->lo(), max_val, hi->dest(), hi->table_index());

   }

 #ifndef PRODUCT

   if (switch_depth == 0) {

     _max_switch_depth = 0;

     _est_switch_depth = log2_intptr((hi-lo+1)-1)+1;

   }

 #endif

   assert(lo <= hi, "must be a non-empty set of ranges");

   if (lo == hi) {

     jump_if_always_fork(lo->dest(), lo->table_index());

   } else {

     assert(lo->hi() == (lo+1)->lo()-1, "contiguous ranges");

     assert(hi->lo() == (hi-1)->hi()+1, "contiguous ranges");

     if (create_jump_tables(key_val, lo, hi)) return;

     int nr = hi - lo + 1;

     SwitchRange* mid = lo + nr/2;

     // if there is an easy choice, pivot at a singleton:

     if (nr > 3 && !mid->is_singleton() && (mid-1)->is_singleton())  mid--;

     assert(lo < mid && mid <= hi, "good pivot choice");

     assert(nr != 2 || mid == hi,   "should pick higher of 2");

     assert(nr != 3 || mid == hi-1, "should pick middle of 3");

     Node *test_val = _gvn.intcon(mid->lo());

     if (mid->is_singleton()) {

       IfNode *iff_ne = jump_if_fork_int(key_val, test_val, BoolTest::ne);

       jump_if_false_fork(iff_ne, mid->dest(), mid->table_index());

       // Special Case:  If there are exactly three ranges, and the high

       // and low range each go to the same place, omit the "gt" test,

       // since it will not discriminate anything.

       bool eq_test_only = (hi == lo+2 && hi->dest() == lo->dest());

       if (eq_test_only) {

         assert(mid == hi-1, "");

       }

       // if there is a higher range, test for it and process it:

       if (mid < hi && !eq_test_only) {

         // two comparisons of same values--should enable 1 test for 2 branches

         // Use BoolTest::le instead of BoolTest::gt

         IfNode *iff_le  = jump_if_fork_int(key_val, test_val, BoolTest::le);

         Node   *iftrue  = _gvn.transform( new (C) IfTrueNode(iff_le) );

         Node   *iffalse = _gvn.transform( new (C) IfFalseNode(iff_le) );

         { PreserveJVMState pjvms(this);

           set_control(iffalse);

           jump_switch_ranges(key_val, mid+1, hi, switch_depth+1);

         }

         set_control(iftrue);

       }

     } else {

       // mid is a range, not a singleton, so treat mid..hi as a unit

       IfNode *iff_ge = jump_if_fork_int(key_val, test_val, BoolTest::ge);

       // if there is a higher range, test for it and process it:

       if (mid == hi) {

         jump_if_true_fork(iff_ge, mid->dest(), mid->table_index());

       } else {

         Node *iftrue  = _gvn.transform( new (C) IfTrueNode(iff_ge) );

         Node *iffalse = _gvn.transform( new (C) IfFalseNode(iff_ge) );

         { PreserveJVMState pjvms(this);

           set_control(iftrue);

           jump_switch_ranges(key_val, mid, hi, switch_depth+1);

         }

         set_control(iffalse);

       }

     }

     // in any case, process the lower range

     jump_switch_ranges(key_val, lo, mid-1, switch_depth+1);

   }

   // Decrease pred_count for each successor after all is done.

   if (switch_depth == 0) {

     int unique_successors = switch_block->num_successors();

     for (int i = 0; i < unique_successors; i++) {

       Block* target = switch_block->successor_at(i);

       // Throw away the pre-allocated path for each unique successor.

       target->next_path_num();

     }

   }

 #ifndef PRODUCT

   _max_switch_depth = MAX2(switch_depth, _max_switch_depth);

   if (TraceOptoParse && Verbose && WizardMode && switch_depth == 0) {

     SwitchRange* r;

     int nsing = 0;

     for( r = lo; r <= hi; r++ ) {

       if( r->is_singleton() )  nsing++;

     }

     tty->print(">>> ");

     _method->print_short_name();

     tty->print_cr(" switch decision tree");

     tty->print_cr("    %d ranges (%d singletons), max_depth=%d, est_depth=%d",

                   hi-lo+1, nsing, _max_switch_depth, _est_switch_depth);

     if (_max_switch_depth > _est_switch_depth) {

       tty->print_cr("******** BAD SWITCH DEPTH ********");

     }

     tty->print("   ");

     for( r = lo; r <= hi; r++ ) {

       r->print(env());

     }

     tty->print_cr("");

   }

 #endif

 }

 void Parse::modf() {

   Node *f2 = pop();

   Node *f1 = pop();

   Node* c = make_runtime_call(RC_LEAF, OptoRuntime::modf_Type(),

                               CAST_FROM_FN_PTR(address, SharedRuntime::frem),

                               "frem", NULL, //no memory effects

                               f1, f2);

   Node* res = _gvn.transform(new (C) ProjNode(c, TypeFunc::Parms + 0));

   push(res);

 }

 void Parse::modd() {

   Node *d2 = pop_pair();

   Node *d1 = pop_pair();

   Node* c = make_runtime_call(RC_LEAF, OptoRuntime::Math_DD_D_Type(),

                               CAST_FROM_FN_PTR(address, SharedRuntime::drem),

                               "drem", NULL, //no memory effects

                               d1, top(), d2, top());

   Node* res_d   = _gvn.transform(new (C) ProjNode(c, TypeFunc::Parms + 0));

 #ifdef ASSERT

   Node* res_top = _gvn.transform(new (C) ProjNode(c, TypeFunc::Parms + 1));

   assert(res_top == top(), "second value must be top");

 #endif

   push_pair(res_d);

 }

 void Parse::l2f() {

   Node* f2 = pop();

   Node* f1 = pop();

   Node* c = make_runtime_call(RC_LEAF, OptoRuntime::l2f_Type(),

                               CAST_FROM_FN_PTR(address, SharedRuntime::l2f),

                               "l2f", NULL, //no memory effects

                               f1, f2);

   Node* res = _gvn.transform(new (C) ProjNode(c, TypeFunc::Parms + 0));

   push(res);

 }

 void Parse::do_irem() {

   // Must keep both values on the expression-stack during null-check

   zero_check_int(peek());

   // Compile-time detect of null-exception?

   if (stopped())  return;

   Node* b = pop();

   Node* a = pop();

   const Type *t = _gvn.type(b);

   if (t != Type::TOP) {

     const TypeInt *ti = t->is_int();

     if (ti->is_con()) {

       int divisor = ti->get_con();

       // check for positive power of 2

       if (divisor > 0 &&

           (divisor & ~(divisor-1)) == divisor) {

         // yes !

         Node *mask = _gvn.intcon((divisor - 1));

         // Sigh, must handle negative dividends

         Node *zero = _gvn.intcon(0);

         IfNode *ifff = jump_if_fork_int(a, zero, BoolTest::lt);

         Node *iff = _gvn.transform( new (C) IfFalseNode(ifff) );

         Node *ift = _gvn.transform( new (C) IfTrueNode (ifff) );

         Node *reg = jump_if_join(ift, iff);

         Node *phi = PhiNode::make(reg, NULL, TypeInt::INT);

         // Negative path; negate/and/negate

         Node *neg = _gvn.transform( new (C) SubINode(zero, a) );

         Node *andn= _gvn.transform( new (C) AndINode(neg, mask) );

         Node *negn= _gvn.transform( new (C) SubINode(zero, andn) );

         phi->init_req(1, negn);

         // Fast positive case

         Node *andx = _gvn.transform( new (C) AndINode(a, mask) );

         phi->init_req(2, andx);

         // Push the merge

         push( _gvn.transform(phi) );

         return;

       }

     }

   }

   // Default case

   push( _gvn.transform( new (C) ModINode(control(),a,b) ) );

 }

 // Handle jsr and jsr_w bytecode

 void Parse::do_jsr() {

   assert(bc() == Bytecodes::_jsr || bc() == Bytecodes::_jsr_w, "wrong bytecode");

   // Store information about current state, tagged with new _jsr_bci

   int return_bci = iter().next_bci();

   int jsr_bci    = (bc() == Bytecodes::_jsr) ? iter().get_dest() : iter().get_far_dest();

   // Update method data

   profile_taken_branch(jsr_bci);

   // The way we do things now, there is only one successor block

   // for the jsr, because the target code is cloned by ciTypeFlow.

   Block* target = successor_for_bci(jsr_bci);

   // What got pushed?

   const Type* ret_addr = target->peek();

   assert(ret_addr->singleton(), "must be a constant (cloned jsr body)");

   // Effect on jsr on stack

   push(_gvn.makecon(ret_addr));

   // Flow to the jsr.

   merge(jsr_bci);

 }

 // Handle ret bytecode

 void Parse::do_ret() {

   // Find to whom we return.

   assert(block()->num_successors() == 1, "a ret can only go one place now");

   Block* target = block()->successor_at(0);

   assert(!target->is_ready(), "our arrival must be expected");

   profile_ret(target->flow()->start());

   int pnum = target->next_path_num();

   merge_common(target, pnum);

 }

 //--------------------------dynamic_branch_prediction--------------------------

 // Try to gather dynamic branch prediction behavior.  Return a probability

 // of the branch being taken and set the "cnt" field.  Returns a -1.0

 // if we need to use static prediction for some reason.

 float Parse::dynamic_branch_prediction(float &cnt) {

   ResourceMark rm;

   cnt  = COUNT_UNKNOWN;

   // Use MethodData information if it is available

   // FIXME: free the ProfileData structure

   ciMethodData* methodData = method()->method_data();

   if (!methodData->is_mature())  return PROB_UNKNOWN;

   ciProfileData* data = methodData->bci_to_data(bci());

   if (!data->is_JumpData())  return PROB_UNKNOWN;

   // get taken and not taken values

   int     taken = data->as_JumpData()->taken();

   int not_taken = 0;

   if (data->is_BranchData()) {

     not_taken = data->as_BranchData()->not_taken();

   }

   // scale the counts to be commensurate with invocation counts:

   taken = method()->scale_count(taken);

   not_taken = method()->scale_count(not_taken);

   // Give up if too few (or too many, in which case the sum will overflow) counts to be meaningful.

   // We also check that individual counters are positive first, overwise the sum can become positive.

   if (taken < 0 || not_taken < 0 || taken + not_taken < 40) {

     if (C->log() != NULL) {

       C->log()->elem("branch target_bci='%d' taken='%d' not_taken='%d'", iter().get_dest(), taken, not_taken);

     }

     return PROB_UNKNOWN;

   }

   // Compute frequency that we arrive here

   float sum = taken + not_taken;

   // Adjust, if this block is a cloned private block but the

   // Jump counts are shared.  Taken the private counts for

   // just this path instead of the shared counts.

   if( block()->count() > 0 )

     sum = block()->count();

   cnt = sum / FreqCountInvocations;

   // Pin probability to sane limits

   float prob;

   if( !taken )

     prob = (0+PROB_MIN) / 2;

   else if( !not_taken )

     prob = (1+PROB_MAX) / 2;

   else {                         // Compute probability of true path

     prob = (float)taken / (float)(taken + not_taken);

     if (prob > PROB_MAX)  prob = PROB_MAX;

     if (prob < PROB_MIN)   prob = PROB_MIN;

   }

   assert((cnt > 0.0f) && (prob > 0.0f),

          "Bad frequency assignment in if");

   if (C->log() != NULL) {

     const char* prob_str = NULL;

     if (prob >= PROB_MAX)  prob_str = (prob == PROB_MAX) ? "max" : "always";

     if (prob <= PROB_MIN)  prob_str = (prob == PROB_MIN) ? "min" : "never";

     char prob_str_buf[30];

     if (prob_str == NULL) {

       sprintf(prob_str_buf, "%g", prob);

       prob_str = prob_str_buf;

     }

     C->log()->elem("branch target_bci='%d' taken='%d' not_taken='%d' cnt='%g' prob='%s'",

                    iter().get_dest(), taken, not_taken, cnt, prob_str);

   }

   return prob;

 }

 //-----------------------------branch_prediction-------------------------------

 float Parse::branch_prediction(float& cnt,

                                BoolTest::mask btest,

                                int target_bci) {

   float prob = dynamic_branch_prediction(cnt);

   // If prob is unknown, switch to static prediction

   if (prob != PROB_UNKNOWN)  return prob;

   prob = PROB_FAIR;                   // Set default value

   if (btest == BoolTest::eq)          // Exactly equal test?

     prob = PROB_STATIC_INFREQUENT;    // Assume its relatively infrequent

   else if (btest == BoolTest::ne)

     prob = PROB_STATIC_FREQUENT;      // Assume its relatively frequent

   // If this is a conditional test guarding a backwards branch,

   // assume its a loop-back edge.  Make it a likely taken branch.

   if (target_bci < bci()) {

     if (is_osr_parse()) {    // Could be a hot OSR'd loop; force deopt

       // Since it's an OSR, we probably have profile data, but since

       // branch_prediction returned PROB_UNKNOWN, the counts are too small.

       // Let's make a special check here for completely zero counts.

       ciMethodData* methodData = method()->method_data();

       if (!methodData->is_empty()) {

         ciProfileData* data = methodData->bci_to_data(bci());

         // Only stop for truly zero counts, which mean an unknown part

         // of the OSR-ed method, and we want to deopt to gather more stats.

         // If you have ANY counts, then this loop is simply 'cold' relative

         // to the OSR loop.

         if (data->as_BranchData()->taken() +

             data->as_BranchData()->not_taken() == 0 ) {

           // This is the only way to return PROB_UNKNOWN:

           return PROB_UNKNOWN;

         }

       }

     }

     prob = PROB_STATIC_FREQUENT;     // Likely to take backwards branch

   }

   assert(prob != PROB_UNKNOWN, "must have some guess at this point");

   return prob;

 }

 // The magic constants are chosen so as to match the output of

 // branch_prediction() when the profile reports a zero taken count.

 // It is important to distinguish zero counts unambiguously, because

 // some branches (e.g., _213_javac.Assembler.eliminate) validly produce

 // very small but nonzero probabilities, which if confused with zero

 // counts would keep the program recompiling indefinitely.

 bool Parse::seems_never_taken(float prob) {

   return prob < PROB_MIN;

 }

 // True if the comparison seems to be the kind that will not change its

 // statistics from true to false.  See comments in adjust_map_after_if.

 // This question is only asked along paths which are already

 // classifed as untaken (by seems_never_taken), so really,

 // if a path is never taken, its controlling comparison is

 // already acting in a stable fashion.  If the comparison

 // seems stable, we will put an expensive uncommon trap

 // on the untaken path.  To be conservative, and to allow

 // partially executed counted loops to be compiled fully,

 // we will plant uncommon traps only after pointer comparisons.

 bool Parse::seems_stable_comparison(BoolTest::mask btest, Node* cmp) {

   for (int depth = 4; depth > 0; depth--) {

     // The following switch can find CmpP here over half the time for

     // dynamic language code rich with type tests.

     // Code using counted loops or array manipulations (typical

     // of benchmarks) will have many (>80%) CmpI instructions.

     switch (cmp->Opcode()) {

     case Op_CmpP:

       // A never-taken null check looks like CmpP/BoolTest::eq.

       // These certainly should be closed off as uncommon traps.

       if (btest == BoolTest::eq)

         return true;

       // A never-failed type check looks like CmpP/BoolTest::ne.

       // Let's put traps on those, too, so that we don't have to compile

       // unused paths with indeterminate dynamic type information.

       if (ProfileDynamicTypes)

         return true;

       return false;

     case Op_CmpI:

       // A small minority (< 10%) of CmpP are masked as CmpI,

       // as if by boolean conversion ((p == q? 1: 0) != 0).

       // Detect that here, even if it hasn't optimized away yet.

       // Specifically, this covers the 'instanceof' operator.

       if (btest == BoolTest::ne || btest == BoolTest::eq) {

         if (_gvn.type(cmp->in(2))->singleton() &&

             cmp->in(1)->is_Phi()) {

           PhiNode* phi = cmp->in(1)->as_Phi();

           int true_path = phi->is_diamond_phi();

           if (true_path > 0 &&

               _gvn.type(phi->in(1))->singleton() &&

               _gvn.type(phi->in(2))->singleton()) {

             // phi->region->if_proj->ifnode->bool->cmp

             BoolNode* bol = phi->in(0)->in(1)->in(0)->in(1)->as_Bool();

             btest = bol->_test._test;

             cmp = bol->in(1);

             continue;

           }

         }

       }

       return false;

     }

   }

   return false;

 }

 //-------------------------------repush_if_args--------------------------------

 // Push arguments of an "if" bytecode back onto the stack by adjusting _sp.

 inline int Parse::repush_if_args() {

 #ifndef PRODUCT

   if (PrintOpto && WizardMode) {

     tty->print("defending against excessive implicit null exceptions on %s @%d in ",

                Bytecodes::name(iter().cur_bc()), iter().cur_bci());

     method()->print_name(); tty->cr();

   }

 #endif

   int bc_depth = - Bytecodes::depth(iter().cur_bc());

   assert(bc_depth == 1 || bc_depth == 2, "only two kinds of branches");

   DEBUG_ONLY(sync_jvms());   // argument(n) requires a synced jvms

   assert(argument(0) != NULL, "must exist");

   assert(bc_depth == 1 || argument(1) != NULL, "two must exist");

   inc_sp(bc_depth);

   return bc_depth;

 }

 //----------------------------------do_ifnull----------------------------------

 void Parse::do_ifnull(BoolTest::mask btest, Node *c) {

   int target_bci = iter().get_dest();

   Block* branch_block = successor_for_bci(target_bci);

   Block* next_block   = successor_for_bci(iter().next_bci());

   float cnt;

   float prob = branch_prediction(cnt, btest, target_bci);

   if (prob == PROB_UNKNOWN) {

     // (An earlier version of do_ifnull omitted this trap for OSR methods.)

 #ifndef PRODUCT

     if (PrintOpto && Verbose)

       tty->print_cr("Never-taken edge stops compilation at bci %d",bci());

 #endif

     repush_if_args(); // to gather stats on loop

     // We need to mark this branch as taken so that if we recompile we will

     // see that it is possible. In the tiered system the interpreter doesn't

     // do profiling and by the time we get to the lower tier from the interpreter

     // the path may be cold again. Make sure it doesn't look untaken

     profile_taken_branch(target_bci, !ProfileInterpreter);

     uncommon_trap(Deoptimization::Reason_unreached,

                   Deoptimization::Action_reinterpret,

                   NULL, "cold");

     if (EliminateAutoBox) {

       // Mark the successor blocks as parsed

       branch_block->next_path_num();

       next_block->next_path_num();

     }

     return;

   }

   explicit_null_checks_inserted++;

   // Generate real control flow

   Node   *tst = _gvn.transform( new (C) BoolNode( c, btest ) );

   // Sanity check the probability value

   assert(prob > 0.0f,"Bad probability in Parser");

  // Need xform to put node in hash table

   IfNode *iff = create_and_xform_if( control(), tst, prob, cnt );

   assert(iff->_prob > 0.0f,"Optimizer made bad probability in parser");

   // True branch

   { PreserveJVMState pjvms(this);

     Node* iftrue  = _gvn.transform( new (C) IfTrueNode (iff) );

     set_control(iftrue);

     if (stopped()) {            // Path is dead?

       explicit_null_checks_elided++;

       if (EliminateAutoBox) {

         // Mark the successor block as parsed

         branch_block->next_path_num();

       }

     } else {                    // Path is live.

       // Update method data

       profile_taken_branch(target_bci);

       adjust_map_after_if(btest, c, prob, branch_block, next_block);

       if (!stopped()) {

         merge(target_bci);

       }

     }

   }

   // False branch

   Node* iffalse = _gvn.transform( new (C) IfFalseNode(iff) );

   set_control(iffalse);

   if (stopped()) {              // Path is dead?

     explicit_null_checks_elided++;

     if (EliminateAutoBox) {

       // Mark the successor block as parsed

       next_block->next_path_num();

     }

   } else  {                     // Path is live.

     // Update method data

     profile_not_taken_branch();

     adjust_map_after_if(BoolTest(btest).negate(), c, 1.0-prob,

                         next_block, branch_block);

   }

 }

 //------------------------------------do_if------------------------------------

 void Parse::do_if(BoolTest::mask btest, Node* c) {

   int target_bci = iter().get_dest();

   Block* branch_block = successor_for_bci(target_bci);

   Block* next_block   = successor_for_bci(iter().next_bci());

   float cnt;

   float prob = branch_prediction(cnt, btest, target_bci);

   float untaken_prob = 1.0 - prob;

   if (prob == PROB_UNKNOWN) {

 #ifndef PRODUCT

     if (PrintOpto && Verbose)

       tty->print_cr("Never-taken edge stops compilation at bci %d",bci());

 #endif

     repush_if_args(); // to gather stats on loop

     // We need to mark this branch as taken so that if we recompile we will

     // see that it is possible. In the tiered system the interpreter doesn't

     // do profiling and by the time we get to the lower tier from the interpreter

     // the path may be cold again. Make sure it doesn't look untaken

     profile_taken_branch(target_bci, !ProfileInterpreter);

     uncommon_trap(Deoptimization::Reason_unreached,

                   Deoptimization::Action_reinterpret,

                   NULL, "cold");

     if (EliminateAutoBox) {

       // Mark the successor blocks as parsed

       branch_block->next_path_num();

       next_block->next_path_num();

     }

     return;

   }

   // Sanity check the probability value

   assert(0.0f < prob && prob < 1.0f,"Bad probability in Parser");

   bool taken_if_true = true;

   // Convert BoolTest to canonical form:

   if (!BoolTest(btest).is_canonical()) {

     btest         = BoolTest(btest).negate();

     taken_if_true = false;

     // prob is NOT updated here; it remains the probability of the taken

     // path (as opposed to the prob of the path guarded by an 'IfTrueNode').

   }

   assert(btest != BoolTest::eq, "!= is the only canonical exact test");

   Node* tst0 = new (C) BoolNode(c, btest);

   Node* tst = _gvn.transform(tst0);

   BoolTest::mask taken_btest   = BoolTest::illegal;

   BoolTest::mask untaken_btest = BoolTest::illegal;

   if (tst->is_Bool()) {

     // Refresh c from the transformed bool node, since it may be

     // simpler than the original c.  Also re-canonicalize btest.

     // This wins when (Bool ne (Conv2B p) 0) => (Bool ne (CmpP p NULL)).

     // That can arise from statements like: if (x instanceof C) ...

     if (tst != tst0) {

       // Canonicalize one more time since transform can change it.

       btest = tst->as_Bool()->_test._test;

       if (!BoolTest(btest).is_canonical()) {

         // Reverse edges one more time...

         tst   = _gvn.transform( tst->as_Bool()->negate(&_gvn) );

         btest = tst->as_Bool()->_test._test;

         assert(BoolTest(btest).is_canonical(), "sanity");

         taken_if_true = !taken_if_true;

       }

       c = tst->in(1);

     }

     BoolTest::mask neg_btest = BoolTest(btest).negate();

     taken_btest   = taken_if_true ?     btest : neg_btest;

     untaken_btest = taken_if_true ? neg_btest :     btest;

   }

   // Generate real control flow

   float true_prob = (taken_if_true ? prob : untaken_prob);

   IfNode* iff = create_and_map_if(control(), tst, true_prob, cnt);

   assert(iff->_prob > 0.0f,"Optimizer made bad probability in parser");

   Node* taken_branch   = new (C) IfTrueNode(iff);

   Node* untaken_branch = new (C) IfFalseNode(iff);

   if (!taken_if_true) {  // Finish conversion to canonical form

     Node* tmp      = taken_branch;

     taken_branch   = untaken_branch;

     untaken_branch = tmp;

   }

   // Branch is taken:

   { PreserveJVMState pjvms(this);

     taken_branch = _gvn.transform(taken_branch);

     set_control(taken_branch);

     if (stopped()) {

       if (EliminateAutoBox) {

         // Mark the successor block as parsed

         branch_block->next_path_num();

       }

     } else {

       // Update method data

       profile_taken_branch(target_bci);

       adjust_map_after_if(taken_btest, c, prob, branch_block, next_block);

       if (!stopped()) {

         merge(target_bci);

       }

     }

   }

   untaken_branch = _gvn.transform(untaken_branch);

   set_control(untaken_branch);

   // Branch not taken.

   if (stopped()) {

     if (EliminateAutoBox) {

       // Mark the successor block as parsed

       next_block->next_path_num();

     }

   } else {

     // Update method data

     profile_not_taken_branch();

     adjust_map_after_if(untaken_btest, c, untaken_prob,

                         next_block, branch_block);

   }

 }

 //----------------------------adjust_map_after_if------------------------------

 // Adjust the JVM state to reflect the result of taking this path.

 // Basically, it means inspecting the CmpNode controlling this

 // branch, seeing how it constrains a tested value, and then

 // deciding if it's worth our while to encode this constraint

 // as graph nodes in the current abstract interpretation map.

 void Parse::adjust_map_after_if(BoolTest::mask btest, Node* c, float prob,

                                 Block* path, Block* other_path) {

   if (stopped() || !c->is_Cmp() || btest == BoolTest::illegal)

     return;                             // nothing to do

   bool is_fallthrough = (path == successor_for_bci(iter().next_bci()));

   if (seems_never_taken(prob) && seems_stable_comparison(btest, c)) {

     // If this might possibly turn into an implicit null check,

     // and the null has never yet been seen, we need to generate

     // an uncommon trap, so as to recompile instead of suffering

     // with very slow branches.  (We'll get the slow branches if

     // the program ever changes phase and starts seeing nulls here.)

     //

     // We do not inspect for a null constant, since a node may

     // optimize to 'null' later on.

     //

     // Null checks, and other tests which expect inequality,

     // show btest == BoolTest::eq along the non-taken branch.

     // On the other hand, type tests, must-be-null tests,

     // and other tests which expect pointer equality,

     // show btest == BoolTest::ne along the non-taken branch.

     // We prune both types of branches if they look unused.

     repush_if_args();

     // We need to mark this branch as taken so that if we recompile we will

     // see that it is possible. In the tiered system the interpreter doesn't

     // do profiling and by the time we get to the lower tier from the interpreter

     // the path may be cold again. Make sure it doesn't look untaken

     if (is_fallthrough) {

       profile_not_taken_branch(!ProfileInterpreter);

     } else {

       profile_taken_branch(iter().get_dest(), !ProfileInterpreter);

     }

     uncommon_trap(Deoptimization::Reason_unreached,

                   Deoptimization::Action_reinterpret,

                   NULL,

                   (is_fallthrough ? "taken always" : "taken never"));

     return;

   }

   Node* val = c->in(1);

   Node* con = c->in(2);

   const Type* tcon = _gvn.type(con);

   const Type* tval = _gvn.type(val);

   bool have_con = tcon->singleton();

   if (tval->singleton()) {

     if (!have_con) {

       // Swap, so constant is in con.

       con  = val;

       tcon = tval;

       val  = c->in(2);

       tval = _gvn.type(val);

       btest = BoolTest(btest).commute();

       have_con = true;

     } else {

       // Do we have two constants?  Then leave well enough alone.

       have_con = false;

     }

   }

   if (!have_con)                        // remaining adjustments need a con

     return;

   sharpen_type_after_if(btest, con, tcon, val, tval);

 }

 static Node* extract_obj_from_klass_load(PhaseGVN* gvn, Node* n) {

   Node* ldk;

   if (n->is_DecodeNKlass()) {

     if (n->in(1)->Opcode() != Op_LoadNKlass) {

       return NULL;

     } else {

       ldk = n->in(1);

     }

   } else if (n->Opcode() != Op_LoadKlass) {

     return NULL;

   } else {

     ldk = n;

   }

   assert(ldk != NULL && ldk->is_Load(), "should have found a LoadKlass or LoadNKlass node");

   Node* adr = ldk->in(MemNode::Address);

   intptr_t off = 0;

   Node* obj = AddPNode::Ideal_base_and_offset(adr, gvn, off);

   if (obj == NULL || off != oopDesc::klass_offset_in_bytes()) // loading oopDesc::_klass?

     return NULL;

   const TypePtr* tp = gvn->type(obj)->is_ptr();

   if (tp == NULL || !(tp->isa_instptr() || tp->isa_aryptr())) // is obj a Java object ptr?

     return NULL;

   return obj;

 }

 void Parse::sharpen_type_after_if(BoolTest::mask btest,

                                   Node* con, const Type* tcon,

                                   Node* val, const Type* tval) {

   // Look for opportunities to sharpen the type of a node

   // whose klass is compared with a constant klass.

   if (btest == BoolTest::eq && tcon->isa_klassptr()) {

     Node* obj = extract_obj_from_klass_load(&_gvn, val);

     const TypeOopPtr* con_type = tcon->isa_klassptr()->as_instance_type();

     if (obj != NULL && (con_type->isa_instptr() || con_type->isa_aryptr())) {

        // Found:

        //   Bool(CmpP(LoadKlass(obj._klass), ConP(Foo.klass)), [eq])

        // or the narrowOop equivalent.

        const Type* obj_type = _gvn.type(obj);

        const TypeOopPtr* tboth = obj_type->join(con_type)->isa_oopptr();

        if (tboth != NULL && tboth->klass_is_exact() && tboth != obj_type &&

            tboth->higher_equal(obj_type)) {

           // obj has to be of the exact type Foo if the CmpP succeeds.

           int obj_in_map = map()->find_edge(obj);

           JVMState* jvms = this->jvms();

           if (obj_in_map >= 0 &&

               (jvms->is_loc(obj_in_map) || jvms->is_stk(obj_in_map))) {

             TypeNode* ccast = new (C) CheckCastPPNode(control(), obj, tboth);

             const Type* tcc = ccast->as_Type()->type();

             assert(tcc != obj_type && tcc->higher_equal(obj_type), "must improve");

             // Delay transform() call to allow recovery of pre-cast value

             // at the control merge.

             _gvn.set_type_bottom(ccast);

             record_for_igvn(ccast);

             // Here's the payoff.

             replace_in_map(obj, ccast);

           }

        }

     }

   }

   int val_in_map = map()->find_edge(val);

   if (val_in_map < 0)  return;          // replace_in_map would be useless

   {

     JVMState* jvms = this->jvms();

     if (!(jvms->is_loc(val_in_map) ||

           jvms->is_stk(val_in_map)))

       return;                           // again, it would be useless

   }

   // Check for a comparison to a constant, and "know" that the compared

   // value is constrained on this path.

   assert(tcon->singleton(), "");

   ConstraintCastNode* ccast = NULL;

   Node* cast = NULL;

   switch (btest) {

   case BoolTest::eq:                    // Constant test?

     {

       const Type* tboth = tcon->join(tval);

       if (tboth == tval)  break;        // Nothing to gain.

       if (tcon->isa_int()) {

         ccast = new (C) CastIINode(val, tboth);

       } else if (tcon == TypePtr::NULL_PTR) {

         // Cast to null, but keep the pointer identity temporarily live.

         ccast = new (C) CastPPNode(val, tboth);

       } else {

         const TypeF* tf = tcon->isa_float_constant();

         const TypeD* td = tcon->isa_double_constant();

         // Exclude tests vs float/double 0 as these could be

         // either +0 or -0.  Just because you are equal to +0

         // doesn't mean you ARE +0!

         // Note, following code also replaces Long and Oop values.

         if ((!tf || tf->_f != 0.0) &&

             (!td || td->_d != 0.0))

           cast = con;                   // Replace non-constant val by con.

       }

     }

     break;

   case BoolTest::ne:

     if (tcon == TypePtr::NULL_PTR) {

       cast = cast_not_null(val, false);

     }

     break;

   default:

     // (At this point we could record int range types with CastII.)

     break;

   }

   if (ccast != NULL) {

     const Type* tcc = ccast->as_Type()->type();

     assert(tcc != tval && tcc->higher_equal(tval), "must improve");

     // Delay transform() call to allow recovery of pre-cast value

     // at the control merge.

     ccast->set_req(0, control());

     _gvn.set_type_bottom(ccast);

     record_for_igvn(ccast);

     cast = ccast;

   }

   if (cast != NULL) {                   // Here's the payoff.

     replace_in_map(val, cast);

   }

 }

 //------------------------------do_one_bytecode--------------------------------

 // Parse this bytecode, and alter the Parsers JVM->Node mapping

 void Parse::do_one_bytecode() {

   Node *a, *b, *c, *d;          // Handy temps

   BoolTest::mask btest;

   int i;

   assert(!has_exceptions(), "bytecode entry state must be clear of throws");

   if (C->check_node_count(NodeLimitFudgeFactor * 5,

                           "out of nodes parsing method")) {

     return;

   }

 #ifdef ASSERT

   // for setting breakpoints

   if (TraceOptoParse) {

     tty->print(" @");

     dump_bci(bci());

     tty->cr();

   }

 #endif

   switch (bc()) {

   case Bytecodes::_nop:

     // do nothing

     break;

   case Bytecodes::_lconst_0:

     push_pair(longcon(0));

     break;

   case Bytecodes::_lconst_1:

     push_pair(longcon(1));

     break;

   case Bytecodes::_fconst_0:

     push(zerocon(T_FLOAT));

     break;

   case Bytecodes::_fconst_1:

     push(makecon(TypeF::ONE));

     break;

   case Bytecodes::_fconst_2:

     push(makecon(TypeF::make(2.0f)));

     break;

   case Bytecodes::_dconst_0:

     push_pair(zerocon(T_DOUBLE));

     break;

   case Bytecodes::_dconst_1:

     push_pair(makecon(TypeD::ONE));

     break;

   case Bytecodes::_iconst_m1:push(intcon(-1)); break;

   case Bytecodes::_iconst_0: push(intcon( 0)); break;

   case Bytecodes::_iconst_1: push(intcon( 1)); break;

   case Bytecodes::_iconst_2: push(intcon( 2)); break;

   case Bytecodes::_iconst_3: push(intcon( 3)); break;

   case Bytecodes::_iconst_4: push(intcon( 4)); break;

   case Bytecodes::_iconst_5: push(intcon( 5)); break;

   case Bytecodes::_bipush:   push(intcon(iter().get_constant_u1())); break;

   case Bytecodes::_sipush:   push(intcon(iter().get_constant_u2())); break;

   case Bytecodes::_aconst_null: push(null());  break;

   case Bytecodes::_ldc:

   case Bytecodes::_ldc_w:

   case Bytecodes::_ldc2_w:

     // If the constant is unresolved, run this BC once in the interpreter.

     {

       ciConstant constant = iter().get_constant();

       if (constant.basic_type() == T_OBJECT &&

           !constant.as_object()->is_loaded()) {

         int index = iter().get_constant_pool_index();

         constantTag tag = iter().get_constant_pool_tag(index);

         uncommon_trap(Deoptimization::make_trap_request

                       (Deoptimization::Reason_unloaded,

                        Deoptimization::Action_reinterpret,

                        index),

                       NULL, tag.internal_name());

         break;

       }

       assert(constant.basic_type() != T_OBJECT || constant.as_object()->is_instance(),

              "must be java_mirror of klass");

       bool pushed = push_constant(constant, true);

       guarantee(pushed, "must be possible to push this constant");

     }

     break;

   case Bytecodes::_aload_0:

     push( local(0) );

     break;

   case Bytecodes::_aload_1:

     push( local(1) );

     break;

   case Bytecodes::_aload_2:

     push( local(2) );

     break;

   case Bytecodes::_aload_3:

     push( local(3) );

     break;

   case Bytecodes::_aload:

     push( local(iter().get_index()) );

     break;

   case Bytecodes::_fload_0:

   case Bytecodes::_iload_0:

     push( local(0) );

     break;

   case Bytecodes::_fload_1:

   case Bytecodes::_iload_1:

     push( local(1) );

     break;

   case Bytecodes::_fload_2:

   case Bytecodes::_iload_2:

     push( local(2) );

     break;

   case Bytecodes::_fload_3:

   case Bytecodes::_iload_3:

     push( local(3) );

     break;

   case Bytecodes::_fload:

   case Bytecodes::_iload:

     push( local(iter().get_index()) );

     break;

   case Bytecodes::_lload_0:

     push_pair_local( 0 );

     break;

   case Bytecodes::_lload_1:

     push_pair_local( 1 );

     break;

   case Bytecodes::_lload_2:

     push_pair_local( 2 );

     break;

   case Bytecodes::_lload_3:

     push_pair_local( 3 );

     break;

   case Bytecodes::_lload:

     push_pair_local( iter().get_index() );

     break;

   case Bytecodes::_dload_0:

     push_pair_local(0);

     break;

   case Bytecodes::_dload_1:

     push_pair_local(1);

     break;

   case Bytecodes::_dload_2:

     push_pair_local(2);

     break;

   case Bytecodes::_dload_3:

     push_pair_local(3);

     break;

   case Bytecodes::_dload:

     push_pair_local(iter().get_index());

     break;

   case Bytecodes::_fstore_0:

   case Bytecodes::_istore_0:

   case Bytecodes::_astore_0:

     set_local( 0, pop() );

     break;

   case Bytecodes::_fstore_1:

   case Bytecodes::_istore_1:

   case Bytecodes::_astore_1:

     set_local( 1, pop() );

     break;

   case Bytecodes::_fstore_2:

   case Bytecodes::_istore_2:

   case Bytecodes::_astore_2:

     set_local( 2, pop() );

     break;

   case Bytecodes::_fstore_3:

   case Bytecodes::_istore_3:

   case Bytecodes::_astore_3:

     set_local( 3, pop() );

     break;

   case Bytecodes::_fstore:

   case Bytecodes::_istore:

   case Bytecodes::_astore:

     set_local( iter().get_index(), pop() );

     break;

   // long stores

   case Bytecodes::_lstore_0:

     set_pair_local( 0, pop_pair() );

     break;

   case Bytecodes::_lstore_1:

     set_pair_local( 1, pop_pair() );

     break;

   case Bytecodes::_lstore_2:

     set_pair_local( 2, pop_pair() );

     break;

   case Bytecodes::_lstore_3:

     set_pair_local( 3, pop_pair() );

     break;

   case Bytecodes::_lstore:

     set_pair_local( iter().get_index(), pop_pair() );

     break;

   // double stores

   case Bytecodes::_dstore_0:

     set_pair_local( 0, dstore_rounding(pop_pair()) );

     break;

   case Bytecodes::_dstore_1:

     set_pair_local( 1, dstore_rounding(pop_pair()) );

     break;

   case Bytecodes::_dstore_2:

     set_pair_local( 2, dstore_rounding(pop_pair()) );

     break;

   case Bytecodes::_dstore_3:

     set_pair_local( 3, dstore_rounding(pop_pair()) );

     break;

   case Bytecodes::_dstore:

     set_pair_local( iter().get_index(), dstore_rounding(pop_pair()) );

     break;

   case Bytecodes::_pop:  dec_sp(1);   break;

   case Bytecodes::_pop2: dec_sp(2);   break;

   case Bytecodes::_swap:

     a = pop();

     b = pop();

     push(a);

     push(b);

     break;

   case Bytecodes::_dup:

     a = pop();

     push(a);

     push(a);

     break;

   case Bytecodes::_dup_x1:

     a = pop();

     b = pop();

     push( a );

     push( b );

     push( a );

     break;

   case Bytecodes::_dup_x2:

     a = pop();

     b = pop();

     c = pop();

     push( a );

     push( c );

     push( b );

     push( a );

     break;

   case Bytecodes::_dup2:

     a = pop();

     b = pop();

     push( b );

     push( a );

     push( b );

     push( a );

     break;

   case Bytecodes::_dup2_x1:

     // before: .. c, b, a

     // after:  .. b, a, c, b, a

     // not tested

     a = pop();

     b = pop();

     c = pop();

     push( b );

     push( a );

     push( c );

     push( b );

     push( a );

     break;

   case Bytecodes::_dup2_x2:

     // before: .. d, c, b, a

     // after:  .. b, a, d, c, b, a

     // not tested

     a = pop();

     b = pop();

     c = pop();

     d = pop();

     push( b );

     push( a );

     push( d );

     push( c );

     push( b );

     push( a );

     break;

   case Bytecodes::_arraylength: {

     // Must do null-check with value on expression stack

     Node *ary = null_check(peek(), T_ARRAY);

     // Compile-time detect of null-exception?

     if (stopped())  return;

     a = pop();

     push(load_array_length(a));

     break;

   }

   case Bytecodes::_baload: array_load(T_BYTE);   break;

   case Bytecodes::_caload: array_load(T_CHAR);   break;

   case Bytecodes::_iaload: array_load(T_INT);    break;

   case Bytecodes::_saload: array_load(T_SHORT);  break;

   case Bytecodes::_faload: array_load(T_FLOAT);  break;

   case Bytecodes::_aaload: array_load(T_OBJECT); break;

   case Bytecodes::_laload: {

     a = array_addressing(T_LONG, 0);

     if (stopped())  return;     // guaranteed null or range check

     dec_sp(2);                  // Pop array and index

     push_pair(make_load(control(), a, TypeLong::LONG, T_LONG, TypeAryPtr::LONGS));

     break;

   }

   case Bytecodes::_daload: {

     a = array_addressing(T_DOUBLE, 0);

     if (stopped())  return;     // guaranteed null or range check

     dec_sp(2);                  // Pop array and index

     push_pair(make_load(control(), a, Type::DOUBLE, T_DOUBLE, TypeAryPtr::DOUBLES));

     break;

   }

   case Bytecodes::_bastore: array_store(T_BYTE);  break;

   case Bytecodes::_castore: array_store(T_CHAR);  break;

   case Bytecodes::_iastore: array_store(T_INT);   break;

   case Bytecodes::_sastore: array_store(T_SHORT); break;

   case Bytecodes::_fastore: array_store(T_FLOAT); break;

   case Bytecodes::_aastore: {

     d = array_addressing(T_OBJECT, 1);

     if (stopped())  return;     // guaranteed null or range check

     array_store_check();

     c = pop();                  // Oop to store

     b = pop();                  // index (already used)

     a = pop();                  // the array itself

     const TypeOopPtr* elemtype  = _gvn.type(a)->is_aryptr()->elem()->make_oopptr();

     const TypeAryPtr* adr_type = TypeAryPtr::OOPS;

     Node* store = store_oop_to_array(control(), a, d, adr_type, c, elemtype, T_OBJECT);

     break;

   }

   case Bytecodes::_lastore: {

     a = array_addressing(T_LONG, 2);

     if (stopped())  return;     // guaranteed null or range check

     c = pop_pair();

     dec_sp(2);                  // Pop array and index

     store_to_memory(control(), a, c, T_LONG, TypeAryPtr::LONGS);

     break;

   }

   case Bytecodes::_dastore: {

     a = array_addressing(T_DOUBLE, 2);

     if (stopped())  return;     // guaranteed null or range check

     c = pop_pair();

     dec_sp(2);                  // Pop array and index

     c = dstore_rounding(c);

     store_to_memory(control(), a, c, T_DOUBLE, TypeAryPtr::DOUBLES);

     break;

   }

   case Bytecodes::_getfield:

     do_getfield();

     break;

   case Bytecodes::_getstatic:

     do_getstatic();

     break;

   case Bytecodes::_putfield:

     do_putfield();

     break;

   case Bytecodes::_putstatic:

     do_putstatic();

     break;

   case Bytecodes::_irem:

     do_irem();

     break;

   case Bytecodes::_idiv:

     // Must keep both values on the expression-stack during null-check

     zero_check_int(peek());

     // Compile-time detect of null-exception?

     if (stopped())  return;

     b = pop();

     a = pop();

     push( _gvn.transform( new (C) DivINode(control(),a,b) ) );

     break;

   case Bytecodes::_imul:

     b = pop(); a = pop();

     push( _gvn.transform( new (C) MulINode(a,b) ) );

     break;

   case Bytecodes::_iadd:

     b = pop(); a = pop();

     push( _gvn.transform( new (C) AddINode(a,b) ) );

     break;

   case Bytecodes::_ineg:

     a = pop();

     push( _gvn.transform( new (C) SubINode(_gvn.intcon(0),a)) );

     break;

   case Bytecodes::_isub:

     b = pop(); a = pop();

     push( _gvn.transform( new (C) SubINode(a,b) ) );

     break;

   case Bytecodes::_iand:

     b = pop(); a = pop();

     push( _gvn.transform( new (C) AndINode(a,b) ) );

     break;

   case Bytecodes::_ior:

     b = pop(); a = pop();

     push( _gvn.transform( new (C) OrINode(a,b) ) );

     break;

   case Bytecodes::_ixor:

     b = pop(); a = pop();

     push( _gvn.transform( new (C) XorINode(a,b) ) );

     break;

   case Bytecodes::_ishl:

     b = pop(); a = pop();

     push( _gvn.transform( new (C) LShiftINode(a,b) ) );

     break;

   case Bytecodes::_ishr:

     b = pop(); a = pop();

     push( _gvn.transform( new (C) RShiftINode(a,b) ) );

     break;

   case Bytecodes::_iushr:

     b = pop(); a = pop();

     push( _gvn.transform( new (C) URShiftINode(a,b) ) );

     break;

   case Bytecodes::_fneg:

     a = pop();

     b = _gvn.transform(new (C) NegFNode (a));

     push(b);

     break;

   case Bytecodes::_fsub:

     b = pop();

     a = pop();

     c = _gvn.transform( new (C) SubFNode(a,b) );

     d = precision_rounding(c);

     push( d );

     break;

   case Bytecodes::_fadd:

     b = pop();

     a = pop();

     c = _gvn.transform( new (C) AddFNode(a,b) );

     d = precision_rounding(c);

     push( d );

     break;

   case Bytecodes::_fmul:

     b = pop();

     a = pop();

     c = _gvn.transform( new (C) MulFNode(a,b) );

     d = precision_rounding(c);

     push( d );

     break;

   case Bytecodes::_fdiv:

     b = pop();

     a = pop();

     c = _gvn.transform( new (C) DivFNode(0,a,b) );

     d = precision_rounding(c);

     push( d );

     break;

   case Bytecodes::_frem:

     if (Matcher::has_match_rule(Op_ModF)) {

       // Generate a ModF node.

       b = pop();

       a = pop();

       c = _gvn.transform( new (C) ModFNode(0,a,b) );

       d = precision_rounding(c);

       push( d );

     }

     else {

       // Generate a call.

       modf();

     }

     break;

   case Bytecodes::_fcmpl:

     b = pop();

     a = pop();

     c = _gvn.transform( new (C) CmpF3Node( a, b));

     push(c);

     break;

   case Bytecodes::_fcmpg:

     b = pop();

     a = pop();

     // Same as fcmpl but need to flip the unordered case.  Swap the inputs,

     // which negates the result sign except for unordered.  Flip the unordered

     // as well by using CmpF3 which implements unordered-lesser instead of

     // unordered-greater semantics.  Finally, commute the result bits.  Result

     // is same as using a CmpF3Greater except we did it with CmpF3 alone.

     c = _gvn.transform( new (C) CmpF3Node( b, a));

     c = _gvn.transform( new (C) SubINode(_gvn.intcon(0),c) );

     push(c);

     break;

   case Bytecodes::_f2i:

     a = pop();

     push(_gvn.transform(new (C) ConvF2INode(a)));

     break;

   case Bytecodes::_d2i:

     a = pop_pair();

     b = _gvn.transform(new (C) ConvD2INode(a));

     push( b );

     break;

   case Bytecodes::_f2d:

     a = pop();

     b = _gvn.transform( new (C) ConvF2DNode(a));

     push_pair( b );

     break;

   case Bytecodes::_d2f:

     a = pop_pair();

     b = _gvn.transform( new (C) ConvD2FNode(a));

     // This breaks _227_mtrt (speed & correctness) and _222_mpegaudio (speed)

     //b = _gvn.transform(new (C) RoundFloatNode(0, b) );

     push( b );

     break;

   case Bytecodes::_l2f:

     if (Matcher::convL2FSupported()) {

       a = pop_pair();

       b = _gvn.transform( new (C) ConvL2FNode(a));

       // For i486.ad, FILD doesn't restrict precision to 24 or 53 bits.

       // Rather than storing the result into an FP register then pushing

       // out to memory to round, the machine instruction that implements

       // ConvL2D is responsible for rounding.

       // c = precision_rounding(b);

       c = _gvn.transform(b);

       push(c);

     } else {

       l2f();

     }

     break;

   case Bytecodes::_l2d:

     a = pop_pair();

     b = _gvn.transform( new (C) ConvL2DNode(a));

     // For i486.ad, rounding is always necessary (see _l2f above).

     // c = dprecision_rounding(b);

     c = _gvn.transform(b);

     push_pair(c);

     break;

   case Bytecodes::_f2l:

     a = pop();

     b = _gvn.transform( new (C) ConvF2LNode(a));

     push_pair(b);

     break;

   case Bytecodes::_d2l:

     a = pop_pair();

     b = _gvn.transform( new (C) ConvD2LNode(a));

     push_pair(b);

     break;

   case Bytecodes::_dsub:

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) SubDNode(a,b) );

     d = dprecision_rounding(c);

     push_pair( d );

     break;

   case Bytecodes::_dadd:

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) AddDNode(a,b) );

     d = dprecision_rounding(c);

     push_pair( d );

     break;

   case Bytecodes::_dmul:

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) MulDNode(a,b) );

     d = dprecision_rounding(c);

     push_pair( d );

     break;

   case Bytecodes::_ddiv:

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) DivDNode(0,a,b) );

     d = dprecision_rounding(c);

     push_pair( d );

     break;

   case Bytecodes::_dneg:

     a = pop_pair();

     b = _gvn.transform(new (C) NegDNode (a));

     push_pair(b);

     break;

   case Bytecodes::_drem:

     if (Matcher::has_match_rule(Op_ModD)) {

       // Generate a ModD node.

       b = pop_pair();

       a = pop_pair();

       // a % b

       c = _gvn.transform( new (C) ModDNode(0,a,b) );

       d = dprecision_rounding(c);

       push_pair( d );

     }

     else {

       // Generate a call.

       modd();

     }

     break;

   case Bytecodes::_dcmpl:

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) CmpD3Node( a, b));

     push(c);

     break;

   case Bytecodes::_dcmpg:

     b = pop_pair();

     a = pop_pair();

     // Same as dcmpl but need to flip the unordered case.

     // Commute the inputs, which negates the result sign except for unordered.

     // Flip the unordered as well by using CmpD3 which implements

     // unordered-lesser instead of unordered-greater semantics.

     // Finally, negate the result bits.  Result is same as using a

     // CmpD3Greater except we did it with CmpD3 alone.

     c = _gvn.transform( new (C) CmpD3Node( b, a));

     c = _gvn.transform( new (C) SubINode(_gvn.intcon(0),c) );

     push(c);

     break;

     // Note for longs -> lo word is on TOS, hi word is on TOS - 1

   case Bytecodes::_land:

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) AndLNode(a,b) );

     push_pair(c);

     break;

   case Bytecodes::_lor:

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) OrLNode(a,b) );

     push_pair(c);

     break;

   case Bytecodes::_lxor:

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) XorLNode(a,b) );

     push_pair(c);

     break;

   case Bytecodes::_lshl:

     b = pop();                  // the shift count

     a = pop_pair();             // value to be shifted

     c = _gvn.transform( new (C) LShiftLNode(a,b) );

     push_pair(c);

     break;

   case Bytecodes::_lshr:

     b = pop();                  // the shift count

     a = pop_pair();             // value to be shifted

     c = _gvn.transform( new (C) RShiftLNode(a,b) );

     push_pair(c);

     break;

   case Bytecodes::_lushr:

     b = pop();                  // the shift count

     a = pop_pair();             // value to be shifted

     c = _gvn.transform( new (C) URShiftLNode(a,b) );

     push_pair(c);

     break;

   case Bytecodes::_lmul:

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) MulLNode(a,b) );

     push_pair(c);

     break;

   case Bytecodes::_lrem:

     // Must keep both values on the expression-stack during null-check

     assert(peek(0) == top(), "long word order");

     zero_check_long(peek(1));

     // Compile-time detect of null-exception?

     if (stopped())  return;

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) ModLNode(control(),a,b) );

     push_pair(c);

     break;

   case Bytecodes::_ldiv:

     // Must keep both values on the expression-stack during null-check

     assert(peek(0) == top(), "long word order");

     zero_check_long(peek(1));

     // Compile-time detect of null-exception?

     if (stopped())  return;

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) DivLNode(control(),a,b) );

     push_pair(c);

     break;

   case Bytecodes::_ladd:

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) AddLNode(a,b) );

     push_pair(c);

     break;

   case Bytecodes::_lsub:

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) SubLNode(a,b) );

     push_pair(c);

     break;

   case Bytecodes::_lcmp:

     // Safepoints are now inserted _before_ branches.  The long-compare

     // bytecode painfully produces a 3-way value (-1,0,+1) which requires a

     // slew of control flow.  These are usually followed by a CmpI vs zero and

     // a branch; this pattern then optimizes to the obvious long-compare and

     // branch.  However, if the branch is backwards there's a Safepoint

     // inserted.  The inserted Safepoint captures the JVM state at the

     // pre-branch point, i.e. it captures the 3-way value.  Thus if a

     // long-compare is used to control a loop the debug info will force

     // computation of the 3-way value, even though the generated code uses a

     // long-compare and branch.  We try to rectify the situation by inserting

     // a SafePoint here and have it dominate and kill the safepoint added at a

     // following backwards branch.  At this point the JVM state merely holds 2

     // longs but not the 3-way value.

     if( UseLoopSafepoints ) {

       switch( iter().next_bc() ) {

       case Bytecodes::_ifgt:

       case Bytecodes::_iflt:

       case Bytecodes::_ifge:

       case Bytecodes::_ifle:

       case Bytecodes::_ifne:

       case Bytecodes::_ifeq:

         // If this is a backwards branch in the bytecodes, add Safepoint

         maybe_add_safepoint(iter().next_get_dest());

       }

     }

     b = pop_pair();

     a = pop_pair();

     c = _gvn.transform( new (C) CmpL3Node( a, b ));

     push(c);

     break;

   case Bytecodes::_lneg:

     a = pop_pair();

     b = _gvn.transform( new (C) SubLNode(longcon(0),a));

     push_pair(b);

     break;

   case Bytecodes::_l2i:

     a = pop_pair();

     push( _gvn.transform( new (C) ConvL2INode(a)));

     break;

   case Bytecodes::_i2l:

     a = pop();

     b = _gvn.transform( new (C) ConvI2LNode(a));

     push_pair(b);

     break;

   case Bytecodes::_i2b:

     // Sign extend

     a = pop();

     a = _gvn.transform( new (C) LShiftINode(a,_gvn.intcon(24)) );

     a = _gvn.transform( new (C) RShiftINode(a,_gvn.intcon(24)) );

     push( a );

     break;

   case Bytecodes::_i2s:

     a = pop();

     a = _gvn.transform( new (C) LShiftINode(a,_gvn.intcon(16)) );

     a = _gvn.transform( new (C) RShiftINode(a,_gvn.intcon(16)) );

     push( a );

     break;

   case Bytecodes::_i2c:

     a = pop();

     push( _gvn.transform( new (C) AndINode(a,_gvn.intcon(0xFFFF)) ) );

     break;

   case Bytecodes::_i2f:

     a = pop();

     b = _gvn.transform( new (C) ConvI2FNode(a) ) ;

     c = precision_rounding(b);

     push (b);

     break;

   case Bytecodes::_i2d:

     a = pop();

     b = _gvn.transform( new (C) ConvI2DNode(a));

     push_pair(b);

     break;

   case Bytecodes::_iinc:        // Increment local

     i = iter().get_index();     // Get local index

     set_local( i, _gvn.transform( new (C) AddINode( _gvn.intcon(iter().get_iinc_con()), local(i) ) ) );

     break;

   // Exit points of synchronized methods must have an unlock node

   case Bytecodes::_return:

     return_current(NULL);

     break;

   case Bytecodes::_ireturn:

   case Bytecodes::_areturn:

   case Bytecodes::_freturn:

     return_current(pop());

     break;

   case Bytecodes::_lreturn:

     return_current(pop_pair());

     break;

   case Bytecodes::_dreturn:

     return_current(pop_pair());

     break;

   case Bytecodes::_athrow:

     // null exception oop throws NULL pointer exception

     null_check(peek());

     if (stopped())  return;

     // Hook the thrown exception directly to subsequent handlers.

     if (BailoutToInterpreterForThrows) {

       // Keep method interpreted from now on.

       uncommon_trap(Deoptimization::Reason_unhandled,

                     Deoptimization::Action_make_not_compilable);

       return;

     }

     if (env()->jvmti_can_post_on_exceptions()) {

       // check if we must post exception events, take uncommon trap if so (with must_throw = false)

       uncommon_trap_if_should_post_on_exceptions(Deoptimization::Reason_unhandled, false);

     }

     // Here if either can_post_on_exceptions or should_post_on_exceptions is false

     add_exception_state(make_exception_state(peek()));

     break;

   case Bytecodes::_goto:   // fall through

   case Bytecodes::_goto_w: {

     int target_bci = (bc() == Bytecodes::_goto) ? iter().get_dest() : iter().get_far_dest();

     // If this is a backwards branch in the bytecodes, add Safepoint

     maybe_add_safepoint(target_bci);

     // Update method data

     profile_taken_branch(target_bci);

     // Merge the current control into the target basic block

     merge(target_bci);

     // See if we can get some profile data and hand it off to the next block

     Block *target_block = block()->successor_for_bci(target_bci);

     if (target_block->pred_count() != 1)  break;

     ciMethodData* methodData = method()->method_data();

     if (!methodData->is_mature())  break;

     ciProfileData* data = methodData->bci_to_data(bci());

     assert( data->is_JumpData(), "" );

     int taken = ((ciJumpData*)data)->taken();

     taken = method()->scale_count(taken);

     target_block->set_count(taken);

     break;

   }

   case Bytecodes::_ifnull:    btest = BoolTest::eq; goto handle_if_null;

   case Bytecodes::_ifnonnull: btest = BoolTest::ne; goto handle_if_null;

   handle_if_null:

     // If this is a backwards branch in the bytecodes, add Safepoint

     maybe_add_safepoint(iter().get_dest());

     a = null();

     b = pop();

     c = _gvn.transform( new (C) CmpPNode(b, a) );

     do_ifnull(btest, c);

     break;

   case Bytecodes::_if_acmpeq: btest = BoolTest::eq; goto handle_if_acmp;

   case Bytecodes::_if_acmpne: btest = BoolTest::ne; goto handle_if_acmp;

   handle_if_acmp:

     // If this is a backwards branch in the bytecodes, add Safepoint

     maybe_add_safepoint(iter().get_dest());

     a = pop();

     b = pop();

     c = _gvn.transform( new (C) CmpPNode(b, a) );

     do_if(btest, c);

     break;

   case Bytecodes::_ifeq: btest = BoolTest::eq; goto handle_ifxx;

   case Bytecodes::_ifne: btest = BoolTest::ne; goto handle_ifxx;

   case Bytecodes::_iflt: btest = BoolTest::lt; goto handle_ifxx;

   case Bytecodes::_ifle: btest = BoolTest::le; goto handle_ifxx;

   case Bytecodes::_ifgt: btest = BoolTest::gt; goto handle_ifxx;

   case Bytecodes::_ifge: btest = BoolTest::ge; goto handle_ifxx;

   handle_ifxx:

     // If this is a backwards branch in the bytecodes, add Safepoint

     maybe_add_safepoint(iter().get_dest());

     a = _gvn.intcon(0);

     b = pop();

     c = _gvn.transform( new (C) CmpINode(b, a) );

     do_if(btest, c);

     break;

   case Bytecodes::_if_icmpeq: btest = BoolTest::eq; goto handle_if_icmp;

   case Bytecodes::_if_icmpne: btest = BoolTest::ne; goto handle_if_icmp;

   case Bytecodes::_if_icmplt: btest = BoolTest::lt; goto handle_if_icmp;

   case Bytecodes::_if_icmple: btest = BoolTest::le; goto handle_if_icmp;

   case Bytecodes::_if_icmpgt: btest = BoolTest::gt; goto handle_if_icmp;

   case Bytecodes::_if_icmpge: btest = BoolTest::ge; goto handle_if_icmp;

   handle_if_icmp:

     // If this is a backwards branch in the bytecodes, add Safepoint

     maybe_add_safepoint(iter().get_dest());

     a = pop();

     b = pop();

     c = _gvn.transform( new (C) CmpINode( b, a ) );

     do_if(btest, c);

     break;

   case Bytecodes::_tableswitch:

     do_tableswitch();

     break;

   case Bytecodes::_lookupswitch:

     do_lookupswitch();

     break;

   case Bytecodes::_invokestatic:

   case Bytecodes::_invokedynamic:

   case Bytecodes::_invokespecial:

   case Bytecodes::_invokevirtual:

   case Bytecodes::_invokeinterface:

     do_call();

     break;

   case Bytecodes::_checkcast:

     do_checkcast();

     break;

   case Bytecodes::_instanceof:

     do_instanceof();

     break;

   case Bytecodes::_anewarray:

     do_anewarray();

     break;

   case Bytecodes::_newarray:

     do_newarray((BasicType)iter().get_index());

     break;

   case Bytecodes::_multianewarray:

     do_multianewarray();

     break;

   case Bytecodes::_new:

     do_new();

     break;

   case Bytecodes::_jsr:

   case Bytecodes::_jsr_w:

     do_jsr();

     break;

   case Bytecodes::_ret:

     do_ret();

     break;

   case Bytecodes::_monitorenter:

     do_monitor_enter();

     break;

   case Bytecodes::_monitorexit:

     do_monitor_exit();

     break;

   case Bytecodes::_breakpoint:

     // Breakpoint set concurrently to compile

     // %%% use an uncommon trap?

     C->record_failure("breakpoint in method");

     return;

   default:

 #ifndef PRODUCT

     map()->dump(99);

 #endif

     tty->print("\nUnhandled bytecode %s\n", Bytecodes::name(bc()) );

     ShouldNotReachHere();

   }

 #ifndef PRODUCT

   IdealGraphPrinter *printer = IdealGraphPrinter::printer();

   if(printer) {

     char buffer[256];

     sprintf(buffer, "Bytecode %d: %s", bci(), Bytecodes::name(bc()));

     bool old = printer->traverse_outs();

     printer->set_traverse_outs(true);

     printer->print_method(C, buffer, 4);

     printer->set_traverse_outs(old);

   }

 #endif

 }