diff --git a/clang/test/Sema/wchar.c b/clang/test/Sema/wchar.c
--- a/clang/test/Sema/wchar.c
+++ b/clang/test/Sema/wchar.c
@@ -4,7 +4,8 @@
 typedef __WCHAR_TYPE__ wchar_t;
 
 #if defined(_WIN32) || defined(_M_IX86) || defined(__CYGWIN__) \
- || defined(_M_X64) || defined(__ORBIS__) || defined(SHORT_WCHAR)
+ || defined(_M_X64) || defined(__ORBIS__) || defined(SHORT_WCHAR) \
+ || defined(_AIX)
   #define WCHAR_T_TYPE unsigned short
 #elif defined(__aarch64__)
   // See AArch64TargetInfo constructor -- unsigned on non-darwin non-OpenBSD non-NetBSD.