[compiler-rt] r257126 - [profile] Add comments to portability macros for readability (NFC)

[Vedant Kumar via llvm-commits]

Author: vedantk
Date: Thu Jan  7 18:49:34 2016
New Revision: 257126

URL: http://llvm.org/viewvc/llvm-project?rev=257126&view=rev
Log:
[profile] Add comments to portability macros for readability (NFC)

Modified:
    compiler-rt/trunk/lib/profile/InstrProfilingPort.h

Modified: compiler-rt/trunk/lib/profile/InstrProfilingPort.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/profile/InstrProfilingPort.h?rev=257126&r1=257125&r2=257126&view=diff
==============================================================================
--- compiler-rt/trunk/lib/profile/InstrProfilingPort.h (original)
+++ compiler-rt/trunk/lib/profile/InstrProfilingPort.h Thu Jan  7 18:49:34 2016
@@ -29,16 +29,16 @@
 #define COMPILER_RT_BOOL_CMPXCHG(Ptr, OldV, NewV)                              \
   (InterlockedCompareExchange64((LONGLONG volatile *)Ptr, (LONGLONG)NewV,      \
                                 (LONGLONG)OldV) == (LONGLONG)OldV)
-#else
+#else /* !defined(_WIN64) */
 #define COMPILER_RT_BOOL_CMPXCHG(Ptr, OldV, NewV)                              \
   (InterlockedCompareExchange((LONG volatile *)Ptr, (LONG)NewV, (LONG)OldV) == \
    (LONG)OldV)
 #endif
-#else
+#else /* !defined(_MSC_VER) */
 #define COMPILER_RT_BOOL_CMPXCHG(Ptr, OldV, NewV)                              \
   __sync_bool_compare_and_swap(Ptr, OldV, NewV)
 #endif
-#else
+#else /* COMPILER_RT_HAS_ATOMICS != 1 */
 #define COMPILER_RT_BOOL_CMPXCHG(Ptr, OldV, NewV)                              \
   BoolCmpXchg((void **)Ptr, OldV, NewV)
 #endif