diff --git a/libc/src/__support/CPP/bit.h b/libc/src/__support/CPP/bit.h
--- a/libc/src/__support/CPP/bit.h
+++ b/libc/src/__support/CPP/bit.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SUPPORT_CPP_BIT_H
 #define LLVM_LIBC_SUPPORT_CPP_BIT_H
 
+#include "src/__support/CPP/type_traits.h"
 #include "src/__support/macros/config.h" // LIBC_HAS_BUILTIN
 
 namespace __llvm_libc::cpp {
@@ -26,8 +27,10 @@
 template <class To, class From> constexpr To bit_cast(const From &from) {
   static_assert(sizeof(To) == sizeof(From), "To and From must be of same size");
 #if defined(LLVM_LIBC_HAS_BUILTIN_BIT_CAST)
-  return __builtin_bit_cast(To, from);
-#else
+  if constexpr (cpp::is_trivially_copyable<To>::value &&
+                cpp::is_trivially_copyable<From>::value)
+    return __builtin_bit_cast(To, from);
+#endif // defined(LLVM_LIBC_HAS_BUILTIN_BIT_CAST)
   To to;
   char *dst = reinterpret_cast<char *>(&to);
   const char *src = reinterpret_cast<const char *>(&from);
@@ -38,7 +41,6 @@
     dst[i] = src[i];
 #endif // defined(LLVM_LIBC_HAS_BUILTIN_MEMCPY_INLINE)
   return to;
-#endif // defined(LLVM_LIBC_HAS_BUILTIN_BIT_CAST)
 }
 
 } // namespace __llvm_libc::cpp
diff --git a/libc/src/__support/CPP/type_traits.h b/libc/src/__support/CPP/type_traits.h
--- a/libc/src/__support/CPP/type_traits.h
+++ b/libc/src/__support/CPP/type_traits.h
@@ -28,6 +28,10 @@
 using true_type = cpp::integral_constant<bool, true>;
 using false_type = cpp::integral_constant<bool, false>;
 
+template <class _Tp>
+struct is_trivially_copyable
+    : public integral_constant<bool, __is_trivially_copyable(_Tp)> {};
+
 template <typename T, typename U> struct is_same : cpp::false_type {};
 template <typename T> struct is_same<T, T> : cpp::true_type {};
 template <typename T, typename U>