Support hints for register pairs.

Change-Id: Ia49dc5bf3e9a2bd481425bfe7fbeea9feb66c8e6
diff --git a/compiler/optimizing/locations.h b/compiler/optimizing/locations.h
index 9ce8d35..ebca1cc 100644
--- a/compiler/optimizing/locations.h
+++ b/compiler/optimizing/locations.h
@@ -151,6 +151,10 @@
     return GetKind() == kFpuRegisterPair;
   }
 
+  bool IsRegisterKind() const {
+    return IsRegister() || IsFpuRegister() || IsRegisterPair() || IsFpuRegisterPair();
+  }
+
   int reg() const {
     DCHECK(IsRegister() || IsFpuRegister());
     return GetPayload();