Lazily save double registers for HCallRuntime instructions within Hydrogen code stubs.

src/arm/lithium-arm.cc

 // Copyright 2012 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 843 matching lines @@
 }
 
 
 void LChunkBuilder::VisitInstruction(HInstruction* current) {
   HInstruction* old_current = current_instruction_;
   current_instruction_ = current;
   if (current->has_position()) position_ = current->position();
   LInstruction* instr = current->CompileToLithium(this);
 
   if (instr != NULL) {
+    // Associate the hydrogen instruction first, since we may need it for
+    // the ClobbersRegisters() or ClobbersDoubleRegisters() calls below.
+    instr->set_hydrogen_value(current);
+
 #if DEBUG
     // Make sure that the lithium instruction has either no fixed register
     // constraints in temps or the result OR no uses that are only used at
     // start. If this invariant doesn't hold, the register allocator can decide
     // to insert a split of a range immediately before the instruction due to an
     // already allocated register needing to be used for the instruction's fixed
     // register constraint. In this case, The register allocator won't see an
     // interference between the split child and the use-at-start (it would if
     // the it was just a plain use), so it is free to move the split child into
     // the same register that is used for the use-at-start.
@@ skipping 16 matching lines @@
     }
 #endif
 
     instr->set_position(position_);
     if (FLAG_stress_pointer_maps && !instr->HasPointerMap()) {
       instr = AssignPointerMap(instr);
     }
     if (FLAG_stress_environments && !instr->HasEnvironment()) {
       instr = AssignEnvironment(instr);
     }
-    instr->set_hydrogen_value(current);
     chunk_->AddInstruction(instr, current_block_);
   }
   current_instruction_ = old_current;
 }
 
 
 LEnvironment* LChunkBuilder::CreateEnvironment(
     HEnvironment* hydrogen_env,
     int* argument_index_accumulator,
     ZoneList<HValue*>* objects_to_materialize) {
@@ skipping 1690 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseRegister(instr->index());
   return DefineAsRegister(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal