Fix debug tracing of live ranges and remove unused code....

src/hydrogen.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5998 matching lines @@
     if (range->IsChild()) {
       parent_index = range->parent()->id();
     } else {
       parent_index = range->id();
     }
     LOperand* op = range->FirstHint();
     int hint_index = -1;
     if (op != NULL && op->IsUnallocated()) hint_index = op->VirtualRegister();
     trace_.Add(" %d %d", parent_index, hint_index);
     UseInterval* cur_interval = range->first_interval();
-    while (cur_interval != NULL) {
+    while (cur_interval != NULL && range->Covers(cur_interval->start())) {
       trace_.Add(" [%d, %d[",
                  cur_interval->start().Value(),
                  cur_interval->end().Value());
       cur_interval = cur_interval->next();
     }
 
     UsePosition* current_pos = range->first_pos();
     while (current_pos != NULL) {
-      if (current_pos->RegisterIsBeneficial()) {
+      if (current_pos->RegisterIsBeneficial() || FLAG_trace_all_uses) {
         trace_.Add(" %d M", current_pos->pos().Value());
       }
       current_pos = current_pos->next();
     }
 
     trace_.Add(" \"\"\n");
   }
 }
 
 
@@ skipping 87 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal