diff --git a/lib/std/builtin.zig b/lib/std/builtin.zig
index ff6d20370ca4ecb2dcccab50eff0b1f5a55e8945..b1f1406684b31659ec33a7d9cf40472f943aaa08 100644
--- a/lib/std/builtin.zig
+++ b/lib/std/builtin.zig
@@ -190,7 +190,7 @@ pub const CallingConvention = enum {
 
 /// This data structure is used by the Zig language code generation and
 /// therefore must be kept in sync with the compiler implementation.
-pub const AddressSpace = enum(u4) {
+pub const AddressSpace = enum(u5) {
     generic,
     gs,
     fs,