A64: Make the simulator sampling friendly.

src/a64/instructions-a64.h

Index: src/a64/instructions-a64.h
diff --git a/src/a64/instructions-a64.h b/src/a64/instructions-a64.h
index b8ef1b200496db30beb872bdcca57d1d060e9ee8..83d22e869f89d5621642dad3aabcdd4c3bdea29b 100644
--- a/src/a64/instructions-a64.h
+++ b/src/a64/instructions-a64.h
@@ -213,10 +213,16 @@ class Instruction {
     return Mask(AddSubExtendedFMask) == AddSubExtendedFixed;
   }
 
+  // Match any loads or stores, including pairs.
   bool IsLoadOrStore() const {
     return Mask(LoadStoreAnyFMask) == LoadStoreAnyFixed;
   }
 
+  // Match any loads, including pairs.
+  bool IsLoad() const;
+  // Match any stores, including pairs.
+  bool IsStore() const;
+
   // Indicate whether Rd can be the stack pointer or the zero register. This
   // does not check that the instruction actually has an Rd field.
   Reg31Mode RdMode() const {