diff --git a/include/intx/builtins.h b/include/intx/builtins.h
deleted file mode 100644
index def76e8e..00000000
--- a/include/intx/builtins.h
+++ /dev/null
@@ -1,67 +0,0 @@
-// builtins: Portable C/C++ compiler builtins.
-// Copyright 2018 Pawel Bylica.
-// Licensed under the Apache License, Version 2.0.
-
-/**
- * @file
- * Implementation of GCC/clang builtins for MSVC compiler.
- */
-
-#pragma once
-
-#ifdef _MSC_VER
-#include <intrin.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/**
- * Returns the number of leading 0-bits in `x`, starting at the most significant bit position.
- * If `x` is 0, the result is undefined.
- */
-static inline int __builtin_clz(unsigned int x)
-{
-    unsigned long most_significant_bit;
-    _BitScanReverse(&most_significant_bit, x);
-    return 31 ^ (int)most_significant_bit;
-}
-
-/**
- * Returns the number of leading 0-bits in `x`, starting at the most significant bit position.
- * If `x` is 0, the result is undefined.
- */
-static inline int __builtin_clzl(unsigned __int64 x)
-{
-    unsigned long most_significant_bit;
-    _BitScanReverse64(&most_significant_bit, x);
-    return 63 ^ (int)most_significant_bit;
-}
-
-/**
- * Returns the number of 1-bits in `x`.
- */
-static inline int __builtin_popcount(unsigned int x)
-{
-    return (int)__popcnt(x);
-}
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif
-
-#ifdef __cplusplus
-namespace builtins
-{
-inline int clz(unsigned int x)
-{
-    return __builtin_clz(x);
-}
-inline int clz(unsigned long x)
-{
-    return __builtin_clzl(x);
-}
-}  // namespace builtins
-#endif