diff --git a/libc/arch-x86/dynamic_function_dispatch.cpp b/libc/arch-x86/dynamic_function_dispatch.cpp
index 70f4b3e..370b372 100644
--- a/libc/arch-x86/dynamic_function_dispatch.cpp
+++ b/libc/arch-x86/dynamic_function_dispatch.cpp
@@ -107,6 +107,13 @@
     RETURN_FUNC(wmemcmp_func, wmemcmp_freebsd);
 }
 
+typedef int wmemset_func(const wchar_t* __lhs, const wchar_t* __rhs, size_t __n);
+DEFINE_IFUNC_FOR(wmemset) {
+    __builtin_cpu_init();
+    if (__builtin_cpu_supports("avx2")) RETURN_FUNC(wmemset_func, wmemset_avx2);
+    RETURN_FUNC(wmemset_func, wmemset_freebsd);
+}
+
 typedef int strcmp_func(const char* __lhs, const char* __rhs);
 DEFINE_IFUNC_FOR(strcmp) {
     __builtin_cpu_init();