Implement CONST_CLASS in optimizing compiler.

Change-Id: Ia8c8dfbef87cb2f7893bfb6e178466154eec9efd
diff --git a/compiler/optimizing/locations.h b/compiler/optimizing/locations.h
index d96131a..bed688b 100644
--- a/compiler/optimizing/locations.h
+++ b/compiler/optimizing/locations.h
@@ -27,6 +27,9 @@
 
 class HConstant;
 class HInstruction;
+class Location;
+
+std::ostream& operator<<(std::ostream& os, const Location& location);
 
 /**
  * A Location is an abstraction over the potential location
@@ -371,7 +374,7 @@
     if (loc.IsRegister()) {
       core_registers_ &= ~(1 << loc.reg());
     } else {
-      DCHECK(loc.IsFpuRegister());
+      DCHECK(loc.IsFpuRegister()) << loc;
       floating_point_registers_ &= ~(1 << loc.reg());
     }
   }
@@ -528,8 +531,6 @@
   DISALLOW_COPY_AND_ASSIGN(LocationSummary);
 };
 
-std::ostream& operator<<(std::ostream& os, const Location& location);
-
 }  // namespace art
 
 #endif  // ART_COMPILER_OPTIMIZING_LOCATIONS_H_