Rename "parallel recompilation" to "concurrent recompilation".

src/hydrogen-instructions.h

 // 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 864 matching lines @@
 
   // This gives the instruction an opportunity to replace itself with an
   // instruction that does the same in some better way.  To replace an
   // instruction with a new one, first add the new instruction to the graph,
   // then return it.  Return NULL to have the instruction deleted.
   virtual HValue* Canonicalize() { return this; }
 
   bool Equals(HValue* other);
   virtual intptr_t Hashcode();
 
-  // Compute unique ids upfront that is safe wrt GC and parallel recompilation.
+  // Compute unique ids upfront that is safe wrt GC and concurrent compilation.
   virtual void FinalizeUniqueValueId() { }
 
   // Printing support.
   virtual void PrintTo(StringStream* stream) = 0;
   void PrintNameTo(StringStream* stream);
   void PrintTypeTo(StringStream* stream);
   void PrintRangeTo(StringStream* stream);
   void PrintChangesTo(StringStream* stream);
 
   const char* Mnemonic() const;
@@ skipping 5900 matching lines @@
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_