diff --git a/clang/lib/Basic/IdentifierTable.cpp b/clang/lib/Basic/IdentifierTable.cpp
index dafacaf88502b..d811aeec84a0f 100644
--- a/clang/lib/Basic/IdentifierTable.cpp
+++ b/clang/lib/Basic/IdentifierTable.cpp
@@ -109,7 +109,7 @@ namespace {
     KEYMSCOMPAT   = 0x800000,
     KEYSYCL       = 0x1000000,
     KEYALLCXX = KEYCXX | KEYCXX11 | KEYCXX20,
-    KEYALL = (0xfffffff & ~KEYNOMS18 &
+    KEYALL = (0x1ffffff & ~KEYNOMS18 &
               ~KEYNOOPENCL) // KEYNOMS18 and KEYNOOPENCL are used to exclude.
   };