510   while (lid != 0) {
 511     LRG& lrg = lrgs(lid);
 512     lrg._area += cost;
 513     raise_pressure(b, lrg, int_pressure, float_pressure);
 514     lid = elements.next();
 515   }
 516   assert(int_pressure.current_pressure() == count_int_pressure(liveout), "the int pressure is incorrect");
 517   assert(float_pressure.current_pressure() == count_float_pressure(liveout), "the float pressure is incorrect");
 518 }
 519 
 520 /*
 521  * Remove dead node if it's not used.
 522  * We only remove projection nodes if the node "defining" the projection is
 523  * dead, for example on x86, if we have a dead Add node we remove its
 524  * RFLAGS node.
 525  */
 526 bool PhaseChaitin::remove_node_if_not_used(Block* b, uint location, Node* n, uint lid, IndexSet* liveout) {
 527   Node* def = n->in(0);
 528   if (!n->is_Proj() ||
 529       (_lrg_map.live_range_id(def) && !liveout->member(_lrg_map.live_range_id(def)))) {
















 530     b->remove_node(location);
 531     LRG& lrg = lrgs(lid);
 532     if (lrg._def == n) {
 533       lrg._def = 0;
 534     }
 535     n->disconnect_inputs(NULL, C);
 536     _cfg.unmap_node_from_block(n);
 537     n->replace_by(C->top());
 538     return true;
 539   }
 540   return false;
 541 }
 542 
 543 /*
 544  * When encountering a fat projection, we might go from a low to high to low
 545  * (since the fat proj only lives at this instruction) going backwards in the
 546  * block. If we find a low to high transition, we record it.
 547  */
 548 void PhaseChaitin::check_for_high_pressure_transition_at_fatproj(uint& block_reg_pressure, uint location, LRG& lrg, Pressure& pressure, const int op_regtype) {
 549   RegMask mask_tmp = lrg.mask();

 510   while (lid != 0) {
 511     LRG& lrg = lrgs(lid);
 512     lrg._area += cost;
 513     raise_pressure(b, lrg, int_pressure, float_pressure);
 514     lid = elements.next();
 515   }
 516   assert(int_pressure.current_pressure() == count_int_pressure(liveout), "the int pressure is incorrect");
 517   assert(float_pressure.current_pressure() == count_float_pressure(liveout), "the float pressure is incorrect");
 518 }
 519 
 520 /*
 521  * Remove dead node if it's not used.
 522  * We only remove projection nodes if the node "defining" the projection is
 523  * dead, for example on x86, if we have a dead Add node we remove its
 524  * RFLAGS node.
 525  */
 526 bool PhaseChaitin::remove_node_if_not_used(Block* b, uint location, Node* n, uint lid, IndexSet* liveout) {
 527   Node* def = n->in(0);
 528   if (!n->is_Proj() ||
 529       (_lrg_map.live_range_id(def) && !liveout->member(_lrg_map.live_range_id(def)))) {
 530     if (n->is_MachProj()) {
 531       // Don't remove KILL projections if their "defining" nodes have
 532       // memory effects (have SCMemProj projection node) -
 533       // they are not dead even when their result is not used.
 534       // For example, compareAndSwapL (and other CAS) and EncodeISOArray nodes.
 535       // The method add_input_to_liveout() keeps such nodes alive (put them on liveout list)
 536       // when it sees SCMemProj node in a block. Unfortunately SCMemProj node could be placed
 537       // in block in such order that KILL MachProj nodes are processed first.
 538       uint cnt = def->outcnt();
 539       for (uint i = 0; i < cnt; i++) {
 540         Node* proj = def->raw_out(i);
 541         if (proj->Opcode() == Op_SCMemProj) {
 542           return false;
 543         }
 544       }
 545     }
 546     b->remove_node(location);
 547     LRG& lrg = lrgs(lid);
 548     if (lrg._def == n) {
 549       lrg._def = 0;
 550     }
 551     n->disconnect_inputs(NULL, C);
 552     _cfg.unmap_node_from_block(n);
 553     n->replace_by(C->top());
 554     return true;
 555   }
 556   return false;
 557 }
 558 
 559 /*
 560  * When encountering a fat projection, we might go from a low to high to low
 561  * (since the fat proj only lives at this instruction) going backwards in the
 562  * block. If we find a low to high transition, we record it.
 563  */
 564 void PhaseChaitin::check_for_high_pressure_transition_at_fatproj(uint& block_reg_pressure, uint location, LRG& lrg, Pressure& pressure, const int op_regtype) {
 565   RegMask mask_tmp = lrg.mask();