Comment to be explicit that the enumeration values for CondCodes matter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57295 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARM.h

@@ -27,6 +27,8 @@ class raw_ostream;
 
 // Enums corresponding to ARM condition codes
 namespace ARMCC {
+  // The CondCodes constants map directly to the 4-bit encoding of the 
+  // condition field for predicated instructions. 
   enum CondCodes {
     EQ,
     NE,