Index: clang/lib/AST/Interp/PrimType.h
===================================================================
--- clang/lib/AST/Interp/PrimType.h
+++ clang/lib/AST/Interp/PrimType.h
@@ -83,18 +83,20 @@
 #define TYPE_SWITCH_CASE(Name, B) \
   case Name: { using T = PrimConv<Name>::T; do {B;} while(0); break; }
 #define TYPE_SWITCH(Expr, B)                                                   \
-  switch (Expr) {                                                              \
-    TYPE_SWITCH_CASE(PT_Sint8, B)                                              \
-    TYPE_SWITCH_CASE(PT_Uint8, B)                                              \
-    TYPE_SWITCH_CASE(PT_Sint16, B)                                             \
-    TYPE_SWITCH_CASE(PT_Uint16, B)                                             \
-    TYPE_SWITCH_CASE(PT_Sint32, B)                                             \
-    TYPE_SWITCH_CASE(PT_Uint32, B)                                             \
-    TYPE_SWITCH_CASE(PT_Sint64, B)                                             \
-    TYPE_SWITCH_CASE(PT_Uint64, B)                                             \
-    TYPE_SWITCH_CASE(PT_Bool, B)                                               \
-    TYPE_SWITCH_CASE(PT_Ptr, B)                                                \
-  }
+  do {                                                                         \
+    switch (Expr) {                                                            \
+      TYPE_SWITCH_CASE(PT_Sint8, B)                                            \
+      TYPE_SWITCH_CASE(PT_Uint8, B)                                            \
+      TYPE_SWITCH_CASE(PT_Sint16, B)                                           \
+      TYPE_SWITCH_CASE(PT_Uint16, B)                                           \
+      TYPE_SWITCH_CASE(PT_Sint32, B)                                           \
+      TYPE_SWITCH_CASE(PT_Uint32, B)                                           \
+      TYPE_SWITCH_CASE(PT_Sint64, B)                                           \
+      TYPE_SWITCH_CASE(PT_Uint64, B)                                           \
+      TYPE_SWITCH_CASE(PT_Bool, B)                                             \
+      TYPE_SWITCH_CASE(PT_Ptr, B)                                              \
+    }                                                                          \
+  } while (0)
 #define COMPOSITE_TYPE_SWITCH(Expr, B, D)                                      \
   switch (Expr) {                                                              \
     TYPE_SWITCH_CASE(PT_Ptr, B)                                                \