diff --git a/libcxx/include/__config b/libcxx/include/__config
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -201,8 +201,6 @@
 #  define _LIBCPP_COMPILER_GCC
 #elif defined(_MSC_VER)
 #  define _LIBCPP_COMPILER_MSVC
-#elif defined(__IBMCPP__)
-#  define _LIBCPP_COMPILER_IBM
 #endif
 
 #if defined(_LIBCPP_COMPILER_GCC) && __cplusplus < 201103L
@@ -506,28 +504,7 @@
 
 #define _LIBCPP_DISABLE_EXTENSION_WARNING
 
-#elif defined(_LIBCPP_COMPILER_IBM)
-
-#define _ALIGNAS(x) __attribute__((__aligned__(x)))
-#define _ALIGNAS_TYPE(x) __attribute__((__aligned__(_LIBCPP_ALIGNOF(x))))
-#define _ATTRIBUTE(x) __attribute__((x))
-#define _LIBCPP_NORETURN __attribute__((noreturn))
-
-#define _LIBCPP_HAS_NO_UNICODE_CHARS
-
-#if defined(_AIX)
-#define __MULTILOCALE_API
-#endif
-
-#define _LIBCPP_HAS_NO_ASAN
-
-#define _LIBCPP_ALWAYS_INLINE __attribute__ ((__always_inline__))
-
-#define _LIBCPP_HAS_NO_VECTOR_EXTENSION
-
-#define _LIBCPP_DISABLE_EXTENSION_WARNING
-
-#endif // _LIBCPP_COMPILER_[CLANG|GCC|MSVC|IBM]
+#endif // _LIBCPP_COMPILER_[CLANG|GCC|MSVC]
 
 #if defined(_LIBCPP_OBJECT_FORMAT_COFF)