diff --git a/libc/docs/dev/code_style.rst b/libc/docs/dev/code_style.rst
index e6fc6df5a0f6b..22a18b7a4cc1d 100644
--- a/libc/docs/dev/code_style.rst
+++ b/libc/docs/dev/code_style.rst
@@ -55,7 +55,7 @@ We define two kinds of macros:
    * ``src/__support/macros/config.h`` - Important compiler and platform
      features. Such macros can be used to produce portable code by
      parameterizing compilation based on the presence or lack of a given
-     feature. e.g., ``LIBC_HAS_BUILTIN``
+     feature. e.g., ``LIBC_HAS_FEATURE``
    * ``src/__support/macros/attributes.h`` - Attributes for functions, types,
      and variables. e.g., ``LIBC_UNUSED``
    * ``src/__support/macros/optimization.h`` - Portable macros for performance
diff --git a/libc/src/__support/CPP/CMakeLists.txt b/libc/src/__support/CPP/CMakeLists.txt
index f76285be52194..84d01fe045160 100644
--- a/libc/src/__support/CPP/CMakeLists.txt
+++ b/libc/src/__support/CPP/CMakeLists.txt
@@ -18,7 +18,6 @@ add_header_library(
     .limits
     .type_traits
     libc.src.__support.macros.attributes
-    libc.src.__support.macros.config
     libc.src.__support.macros.sanitizer
 )
 
@@ -157,7 +156,6 @@ add_header_library(
   DEPENDS
     libc.include.llvm-libc-macros.stdfix_macros
     libc.src.__support.macros.attributes
-    libc.src.__support.macros.config
     libc.src.__support.macros.properties.types
 )
 
diff --git a/libc/src/__support/CPP/atomic.h b/libc/src/__support/CPP/atomic.h
index b74cb5981dbaf..5e428940565b9 100644
--- a/libc/src/__support/CPP/atomic.h
+++ b/libc/src/__support/CPP/atomic.h
@@ -71,10 +71,11 @@ template <typename T> struct Atomic {
 
   T load(MemoryOrder mem_ord = MemoryOrder::SEQ_CST,
          [[maybe_unused]] MemoryScope mem_scope = MemoryScope::DEVICE) {
-    if constexpr (LIBC_HAS_BUILTIN(__scoped_atomic_load_n))
-      return __scoped_atomic_load_n(&val, int(mem_ord), (int)(mem_scope));
-    else
-      return __atomic_load_n(&val, int(mem_ord));
+#if __has_builtin(__scoped_atomic_load_n)
+    return __scoped_atomic_load_n(&val, int(mem_ord), (int)(mem_scope));
+#else
+    return __atomic_load_n(&val, int(mem_ord));
+#endif
   }
 
   // Atomic store.
@@ -85,10 +86,11 @@ template <typename T> struct Atomic {
 
   void store(T rhs, MemoryOrder mem_ord = MemoryOrder::SEQ_CST,
              [[maybe_unused]] MemoryScope mem_scope = MemoryScope::DEVICE) {
-    if constexpr (LIBC_HAS_BUILTIN(__scoped_atomic_store_n))
-      __scoped_atomic_store_n(&val, rhs, int(mem_ord), (int)(mem_scope));
-    else
-      __atomic_store_n(&val, rhs, int(mem_ord));
+#if __has_builtin(__scoped_atomic_store_n)
+    __scoped_atomic_store_n(&val, rhs, int(mem_ord), (int)(mem_scope));
+#else
+    __atomic_store_n(&val, rhs, int(mem_ord));
+#endif
   }
 
   // Atomic compare exchange
@@ -101,47 +103,51 @@ template <typename T> struct Atomic {
 
   T exchange(T desired, MemoryOrder mem_ord = MemoryOrder::SEQ_CST,
              [[maybe_unused]] MemoryScope mem_scope = MemoryScope::DEVICE) {
-    if constexpr (LIBC_HAS_BUILTIN(__scoped_atomic_exchange_n))
-      return __scoped_atomic_exchange_n(&val, desired, int(mem_ord),
-                                        (int)(mem_scope));
-    else
-      return __atomic_exchange_n(&val, desired, int(mem_ord));
+#if __has_builtin(__scoped_atomic_exchange_n)
+    return __scoped_atomic_exchange_n(&val, desired, int(mem_ord),
+                                      (int)(mem_scope));
+#else
+    return __atomic_exchange_n(&val, desired, int(mem_ord));
+#endif
   }
 
   T fetch_add(T increment, MemoryOrder mem_ord = MemoryOrder::SEQ_CST,
               [[maybe_unused]] MemoryScope mem_scope = MemoryScope::DEVICE) {
-    if constexpr (LIBC_HAS_BUILTIN(__scoped_atomic_fetch_add))
-      return __scoped_atomic_fetch_add(&val, increment, int(mem_ord),
-                                       (int)(mem_scope));
-    else
-      return __atomic_fetch_add(&val, increment, int(mem_ord));
+#if __has_builtin(__scoped_atomic_fetch_add)
+    return __scoped_atomic_fetch_add(&val, increment, int(mem_ord),
+                                     (int)(mem_scope));
+#else
+    return __atomic_fetch_add(&val, increment, int(mem_ord));
+#endif
   }
 
   T fetch_or(T mask, MemoryOrder mem_ord = MemoryOrder::SEQ_CST,
              [[maybe_unused]] MemoryScope mem_scope = MemoryScope::DEVICE) {
-    if constexpr (LIBC_HAS_BUILTIN(__scoped_atomic_fetch_or))
-      return __scoped_atomic_fetch_or(&val, mask, int(mem_ord),
-                                      (int)(mem_scope));
-    else
-      return __atomic_fetch_or(&val, mask, int(mem_ord));
+#if __has_builtin(__scoped_atomic_fetch_or)
+    return __scoped_atomic_fetch_or(&val, mask, int(mem_ord), (int)(mem_scope));
+#else
+    return __atomic_fetch_or(&val, mask, int(mem_ord));
+#endif
   }
 
   T fetch_and(T mask, MemoryOrder mem_ord = MemoryOrder::SEQ_CST,
               [[maybe_unused]] MemoryScope mem_scope = MemoryScope::DEVICE) {
-    if constexpr (LIBC_HAS_BUILTIN(__scoped_atomic_fetch_and))
-      return __scoped_atomic_fetch_and(&val, mask, int(mem_ord),
-                                       (int)(mem_scope));
-    else
-      return __atomic_fetch_and(&val, mask, int(mem_ord));
+#if __has_builtin(__scoped_atomic_fetch_and)
+    return __scoped_atomic_fetch_and(&val, mask, int(mem_ord),
+                                     (int)(mem_scope));
+#else
+    return __atomic_fetch_and(&val, mask, int(mem_ord));
+#endif
   }
 
   T fetch_sub(T decrement, MemoryOrder mem_ord = MemoryOrder::SEQ_CST,
               [[maybe_unused]] MemoryScope mem_scope = MemoryScope::DEVICE) {
-    if constexpr (LIBC_HAS_BUILTIN(__scoped_atomic_fetch_sub))
-      return __scoped_atomic_fetch_sub(&val, decrement, int(mem_ord),
-                                       (int)(mem_scope));
-    else
-      return __atomic_fetch_sub(&val, decrement, int(mem_ord));
+#if __has_builtin(__scoped_atomic_fetch_sub)
+    return __scoped_atomic_fetch_sub(&val, decrement, int(mem_ord),
+                                     (int)(mem_scope));
+#else
+    return __atomic_fetch_sub(&val, decrement, int(mem_ord));
+#endif
   }
 
   // Set the value without using an atomic operation. This is useful
@@ -166,7 +172,7 @@ LIBC_INLINE void atomic_thread_fence([[maybe_unused]] MemoryOrder mem_ord) {
 // except no instructions for memory ordering are issued. Only reordering of
 // the instructions by the compiler is suppressed as order instructs.
 LIBC_INLINE void atomic_signal_fence([[maybe_unused]] MemoryOrder mem_ord) {
-#if LIBC_HAS_BUILTIN(__atomic_signal_fence)
+#if __has_builtin(__atomic_signal_fence)
   __atomic_signal_fence(static_cast<int>(mem_ord));
 #else
   // if the builtin is not ready, use asm as a full compiler barrier.
diff --git a/libc/src/__support/CPP/bit.h b/libc/src/__support/CPP/bit.h
index 3f2fbec944054..17d2e5b26e353 100644
--- a/libc/src/__support/CPP/bit.h
+++ b/libc/src/__support/CPP/bit.h
@@ -14,14 +14,13 @@
 #include "src/__support/CPP/limits.h" // numeric_limits
 #include "src/__support/CPP/type_traits.h"
 #include "src/__support/macros/attributes.h"
-#include "src/__support/macros/config.h" // LIBC_HAS_BUILTIN
 #include "src/__support/macros/sanitizer.h"
 
 #include <stdint.h>
 
 namespace LIBC_NAMESPACE::cpp {
 
-#if LIBC_HAS_BUILTIN(__builtin_memcpy_inline)
+#if __has_builtin(__builtin_memcpy_inline)
 #define LLVM_LIBC_HAS_BUILTIN_MEMCPY_INLINE
 #endif
 
@@ -36,20 +35,20 @@ LIBC_INLINE constexpr cpp::enable_if_t<
     To>
 bit_cast(const From &from) {
   MSAN_UNPOISON(&from, sizeof(From));
-#if LIBC_HAS_BUILTIN(__builtin_bit_cast)
+#if __has_builtin(__builtin_bit_cast)
   return __builtin_bit_cast(To, from);
 #else
   To to;
   char *dst = reinterpret_cast<char *>(&to);
   const char *src = reinterpret_cast<const char *>(&from);
-#if LIBC_HAS_BUILTIN(__builtin_memcpy_inline)
+#if __has_builtin(__builtin_memcpy_inline)
   __builtin_memcpy_inline(dst, src, sizeof(To));
 #else
   for (unsigned i = 0; i < sizeof(To); ++i)
     dst[i] = src[i];
-#endif // LIBC_HAS_BUILTIN(__builtin_memcpy_inline)
+#endif // __has_builtin(__builtin_memcpy_inline)
   return to;
-#endif // LIBC_HAS_BUILTIN(__builtin_bit_cast)
+#endif // __has_builtin(__builtin_bit_cast)
 }
 
 template <typename T>
@@ -94,7 +93,7 @@ countr_zero(T value) {
   }
   return zero_bits;
 }
-#if LIBC_HAS_BUILTIN(__builtin_ctzs)
+#if __has_builtin(__builtin_ctzs)
 ADD_SPECIALIZATION(countr_zero, unsigned short, __builtin_ctzs)
 #endif
 ADD_SPECIALIZATION(countr_zero, unsigned int, __builtin_ctz)
@@ -124,7 +123,7 @@ countl_zero(T value) {
   }
   return zero_bits;
 }
-#if LIBC_HAS_BUILTIN(__builtin_clzs)
+#if __has_builtin(__builtin_clzs)
 ADD_SPECIALIZATION(countl_zero, unsigned short, __builtin_clzs)
 #endif
 ADD_SPECIALIZATION(countl_zero, unsigned int, __builtin_clz)
diff --git a/libc/src/__support/CPP/type_traits/is_destructible.h b/libc/src/__support/CPP/type_traits/is_destructible.h
index d47de1cc797b2..f94fe309ac8f7 100644
--- a/libc/src/__support/CPP/type_traits/is_destructible.h
+++ b/libc/src/__support/CPP/type_traits/is_destructible.h
@@ -16,12 +16,11 @@
 #include "src/__support/CPP/type_traits/true_type.h"
 #include "src/__support/CPP/type_traits/type_identity.h"
 #include "src/__support/macros/attributes.h"
-#include "src/__support/macros/config.h"
 
 namespace LIBC_NAMESPACE::cpp {
 
 // is_destructible
-#if LIBC_HAS_BUILTIN(__is_destructible)
+#if __has_builtin(__is_destructible)
 template <typename T>
 struct is_destructible : bool_constant<__is_destructible(T)> {};
 #else
diff --git a/libc/src/__support/CPP/type_traits/is_function.h b/libc/src/__support/CPP/type_traits/is_function.h
index 557b3224484bc..0eba5860ad607 100644
--- a/libc/src/__support/CPP/type_traits/is_function.h
+++ b/libc/src/__support/CPP/type_traits/is_function.h
@@ -12,12 +12,11 @@
 #include "src/__support/CPP/type_traits/is_const.h"
 #include "src/__support/CPP/type_traits/is_reference.h"
 #include "src/__support/macros/attributes.h"
-#include "src/__support/macros/config.h"
 
 namespace LIBC_NAMESPACE::cpp {
 
 // is_function
-#if LIBC_HAS_BUILTIN(__is_function)
+#if __has_builtin(__is_function)
 template <typename T>
 struct is_function : integral_constant<bool, __is_function(T)> {};
 #else
diff --git a/libc/src/__support/CPP/type_traits/is_lvalue_reference.h b/libc/src/__support/CPP/type_traits/is_lvalue_reference.h
index f52e303afad2a..1dff57f186a3a 100644
--- a/libc/src/__support/CPP/type_traits/is_lvalue_reference.h
+++ b/libc/src/__support/CPP/type_traits/is_lvalue_reference.h
@@ -12,12 +12,11 @@
 #include "src/__support/CPP/type_traits/false_type.h"
 #include "src/__support/CPP/type_traits/true_type.h"
 #include "src/__support/macros/attributes.h"
-#include "src/__support/macros/config.h"
 
 namespace LIBC_NAMESPACE::cpp {
 
 // is_lvalue_reference
-#if LIBC_HAS_BUILTIN(__is_lvalue_reference)
+#if __has_builtin(__is_lvalue_reference)
 template <typename T>
 struct is_lvalue_reference : bool_constant<__is_lvalue_reference(T)> {};
 #else
diff --git a/libc/src/__support/CPP/type_traits/is_reference.h b/libc/src/__support/CPP/type_traits/is_reference.h
index c017028edf411..bbfb2b7359c3e 100644
--- a/libc/src/__support/CPP/type_traits/is_reference.h
+++ b/libc/src/__support/CPP/type_traits/is_reference.h
@@ -12,12 +12,11 @@
 #include "src/__support/CPP/type_traits/false_type.h"
 #include "src/__support/CPP/type_traits/true_type.h"
 #include "src/__support/macros/attributes.h"
-#include "src/__support/macros/config.h"
 
 namespace LIBC_NAMESPACE::cpp {
 
 // is_reference
-#if LIBC_HAS_BUILTIN(__is_reference)
+#if __has_builtin(__is_reference)
 template <typename T> struct is_reference : bool_constant<__is_reference(T)> {};
 #else
 template <typename T> struct is_reference : public false_type {};
diff --git a/libc/src/__support/CPP/type_traits/is_rvalue_reference.h b/libc/src/__support/CPP/type_traits/is_rvalue_reference.h
index f0487e41c998f..3efbbe6b033a0 100644
--- a/libc/src/__support/CPP/type_traits/is_rvalue_reference.h
+++ b/libc/src/__support/CPP/type_traits/is_rvalue_reference.h
@@ -12,12 +12,11 @@
 #include "src/__support/CPP/type_traits/false_type.h"
 #include "src/__support/CPP/type_traits/true_type.h"
 #include "src/__support/macros/attributes.h"
-#include "src/__support/macros/config.h"
 
 namespace LIBC_NAMESPACE::cpp {
 
 // is_rvalue_reference
-#if LIBC_HAS_BUILTIN(__is_rvalue_reference)
+#if __has_builtin(__is_rvalue_reference)
 template <typename T>
 struct is_rvalue_reference : bool_constant<__is_rvalue_reference(T)> {};
 #else
diff --git a/libc/src/__support/CPP/type_traits/is_trivially_destructible.h b/libc/src/__support/CPP/type_traits/is_trivially_destructible.h
index 3345149433afc..37e0e869266e1 100644
--- a/libc/src/__support/CPP/type_traits/is_trivially_destructible.h
+++ b/libc/src/__support/CPP/type_traits/is_trivially_destructible.h
@@ -11,12 +11,11 @@
 #include "src/__support/CPP/type_traits/bool_constant.h"
 #include "src/__support/CPP/type_traits/is_destructible.h"
 #include "src/__support/macros/attributes.h"
-#include "src/__support/macros/config.h"
 
 namespace LIBC_NAMESPACE::cpp {
 
 // is_trivially_destructible
-#if LIBC_HAS_BUILTIN(__is_trivially_destructible)
+#if __has_builtin(__is_trivially_destructible)
 template <typename T>
 struct is_trivially_destructible
     : public bool_constant<__is_trivially_destructible(T)> {};
@@ -25,7 +24,7 @@ template <typename T>
 struct is_trivially_destructible
     : public bool_constant<cpp::is_destructible_v<T> &&__has_trivial_destructor(
           T)> {};
-#endif // LIBC_HAS_BUILTIN(__is_trivially_destructible)
+#endif // __has_builtin(__is_trivially_destructible)
 template <typename T>
 LIBC_INLINE_VAR constexpr bool is_trivially_destructible_v =
     is_trivially_destructible<T>::value;
diff --git a/libc/src/__support/CPP/type_traits/remove_all_extents.h b/libc/src/__support/CPP/type_traits/remove_all_extents.h
index bff6341d3e456..5941b82bbc161 100644
--- a/libc/src/__support/CPP/type_traits/remove_all_extents.h
+++ b/libc/src/__support/CPP/type_traits/remove_all_extents.h
@@ -9,14 +9,13 @@
 #define LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_REMOVE_ALL_EXTENTS_H
 
 #include "src/__support/CPP/type_traits/type_identity.h"
-#include "src/__support/macros/config.h"
 
 #include <stddef.h> // size_t
 
 namespace LIBC_NAMESPACE::cpp {
 
 // remove_all_extents
-#if LIBC_HAS_BUILTIN(__remove_all_extents)
+#if __has_builtin(__remove_all_extents)
 template <typename T> using remove_all_extents_t = __remove_all_extents(T);
 template <typename T>
 struct remove_all_extents : cpp::type_identity<remove_all_extents_t<T>> {};
diff --git a/libc/src/__support/FPUtil/CMakeLists.txt b/libc/src/__support/FPUtil/CMakeLists.txt
index 4ded70a675ea8..538d732ad9ebc 100644
--- a/libc/src/__support/FPUtil/CMakeLists.txt
+++ b/libc/src/__support/FPUtil/CMakeLists.txt
@@ -6,7 +6,6 @@ add_header_library(
     libc.include.fenv
     libc.include.math
     libc.src.__support.macros.attributes
-    libc.src.__support.macros.config
     libc.src.errno.errno
 )
 
diff --git a/libc/src/__support/FPUtil/FEnvImpl.h b/libc/src/__support/FPUtil/FEnvImpl.h
index a6a533dcfdf4a..6086d5d3de2dc 100644
--- a/libc/src/__support/FPUtil/FEnvImpl.h
+++ b/libc/src/__support/FPUtil/FEnvImpl.h
@@ -11,7 +11,6 @@
 
 #include "include/llvm-libc-macros/math-macros.h"
 #include "src/__support/macros/attributes.h" // LIBC_INLINE
-#include "src/__support/macros/config.h"     // LIBC_HAS_BUILTIN
 #include "src/__support/macros/properties/architectures.h"
 #include "src/errno/libc_errno.h"
 #include <fenv.h>
diff --git a/libc/src/__support/FPUtil/gpu/FMA.h b/libc/src/__support/FPUtil/gpu/FMA.h
index 86bc860314961..ef1cd26a72dd7 100644
--- a/libc/src/__support/FPUtil/gpu/FMA.h
+++ b/libc/src/__support/FPUtil/gpu/FMA.h
@@ -10,12 +10,12 @@
 #define LLVM_LIBC_SRC___SUPPORT_FPUTIL_GPU_FMA_H
 
 #include "src/__support/CPP/type_traits.h"
-#include "src/__support/macros/config.h"
 
-// These intrinsics map to the FMA instrunctions in the target ISA for the GPU.
+// These intrinsics map to the FMA instructions in the target ISA for the GPU.
 // The default rounding mode generated from these will be to the nearest even.
-static_assert(LIBC_HAS_BUILTIN(__builtin_fma), "FMA builtins must be defined");
-static_assert(LIBC_HAS_BUILTIN(__builtin_fmaf), "FMA builtins must be defined");
+#if !__has_builtin(__builtin_fma) || !__has_builtin(__builtin_fmaf)
+#error "FMA builtins must be defined");
+#endif
 
 namespace LIBC_NAMESPACE {
 namespace fputil {
diff --git a/libc/src/__support/macros/config.h b/libc/src/__support/macros/config.h
index fcc8f551a783f..97599566eaa5e 100644
--- a/libc/src/__support/macros/config.h
+++ b/libc/src/__support/macros/config.h
@@ -13,24 +13,6 @@
 #ifndef LLVM_LIBC_SRC___SUPPORT_MACROS_CONFIG_H
 #define LLVM_LIBC_SRC___SUPPORT_MACROS_CONFIG_H
 
-// LIBC_HAS_BUILTIN()
-//
-// Checks whether the compiler supports a Clang Feature Checking Macro, and if
-// so, checks whether it supports the provided builtin function "x" where x
-// is one of the functions noted in
-// https://clang.llvm.org/docs/LanguageExtensions.html
-//
-// Note: Use this macro to avoid an extra level of #ifdef __has_builtin check.
-// http://releases.llvm.org/3.3/tools/clang/docs/LanguageExtensions.html
-
-// Compiler builtin-detection.
-// clang.llvm.org/docs/LanguageExtensions.html#has-builtin
-#ifdef __has_builtin
-#define LIBC_HAS_BUILTIN(x) __has_builtin(x)
-#else
-#define LIBC_HAS_BUILTIN(x) 0
-#endif
-
 // Compiler feature-detection.
 // clang.llvm.org/docs/LanguageExtensions.html#has-feature-and-has-extension
 #ifdef __has_feature
diff --git a/libc/src/__support/macros/optimization.h b/libc/src/__support/macros/optimization.h
index ae97efcaa4170..59886ca44be12 100644
--- a/libc/src/__support/macros/optimization.h
+++ b/libc/src/__support/macros/optimization.h
@@ -11,7 +11,6 @@
 #define LLVM_LIBC_SRC___SUPPORT_MACROS_OPTIMIZATION_H
 
 #include "src/__support/macros/attributes.h"          // LIBC_INLINE
-#include "src/__support/macros/config.h"              // LIBC_HAS_BUILTIN
 #include "src/__support/macros/properties/compiler.h" // LIBC_COMPILER_IS_CLANG
 
 // We use a template to implement likely/unlikely to make sure that we don't
diff --git a/libc/src/__support/macros/sanitizer.h b/libc/src/__support/macros/sanitizer.h
index fc66c2005c42d..bd9b62b7121a1 100644
--- a/libc/src/__support/macros/sanitizer.h
+++ b/libc/src/__support/macros/sanitizer.h
@@ -47,8 +47,7 @@
 // Functions to unpoison memory
 //-----------------------------------------------------------------------------
 
-#if defined(LIBC_HAVE_MEMORY_SANITIZER) &&                                     \
-    LIBC_HAS_BUILTIN(__builtin_constant_p)
+#if defined(LIBC_HAVE_MEMORY_SANITIZER) && __has_builtin(__builtin_constant_p)
 // Only perform MSAN unpoison in non-constexpr context.
 #include <sanitizer/msan_interface.h>
 #define MSAN_UNPOISON(addr, size)                                              \
diff --git a/libc/src/__support/math_extras.h b/libc/src/__support/math_extras.h
index 28ee1be8b9999..70a8800b285d0 100644
--- a/libc/src/__support/math_extras.h
+++ b/libc/src/__support/math_extras.h
@@ -14,7 +14,6 @@
 #include "src/__support/CPP/limits.h"        // CHAR_BIT, numeric_limits
 #include "src/__support/CPP/type_traits.h"   // is_unsigned_v
 #include "src/__support/macros/attributes.h" // LIBC_INLINE
-#include "src/__support/macros/config.h"     // LIBC_HAS_BUILTIN
 
 namespace LIBC_NAMESPACE {
 
@@ -61,7 +60,7 @@ add_with_carry(T a, T b, T carry_in) {
   return add_with_carry_const<T>(a, b, carry_in);
 }
 
-#if LIBC_HAS_BUILTIN(__builtin_addc)
+#if __has_builtin(__builtin_addc)
 // https://clang.llvm.org/docs/LanguageExtensions.html#multiprecision-arithmetic-builtins
 
 template <>
@@ -129,7 +128,7 @@ add_with_carry<unsigned long long>(unsigned long long a, unsigned long long b,
   }
 }
 
-#endif // LIBC_HAS_BUILTIN(__builtin_addc)
+#endif // __has_builtin(__builtin_addc)
 
 // Subtract with borrow
 template <typename T> struct DiffBorrow {
@@ -157,7 +156,7 @@ sub_with_borrow(T a, T b, T borrow_in) {
   return sub_with_borrow_const<T>(a, b, borrow_in);
 }
 
-#if LIBC_HAS_BUILTIN(__builtin_subc)
+#if __has_builtin(__builtin_subc)
 // https://clang.llvm.org/docs/LanguageExtensions.html#multiprecision-arithmetic-builtins
 
 template <>
@@ -225,7 +224,7 @@ sub_with_borrow<unsigned long long>(unsigned long long a, unsigned long long b,
   }
 }
 
-#endif // LIBC_HAS_BUILTIN(__builtin_subc)
+#endif // __has_builtin(__builtin_subc)
 
 template <typename T>
 [[nodiscard]] LIBC_INLINE constexpr cpp::enable_if_t<cpp::is_unsigned_v<T>, int>
diff --git a/libc/src/__support/memory_size.h b/libc/src/__support/memory_size.h
index 7bd16a1695be9..491123bbabf30 100644
--- a/libc/src/__support/memory_size.h
+++ b/libc/src/__support/memory_size.h
@@ -19,7 +19,7 @@
 namespace LIBC_NAMESPACE {
 namespace internal {
 template <class T> LIBC_INLINE bool mul_overflow(T a, T b, T *res) {
-#if LIBC_HAS_BUILTIN(__builtin_mul_overflow)
+#if __has_builtin(__builtin_mul_overflow)
   return __builtin_mul_overflow(a, b, res);
 #else
   T max = cpp::numeric_limits<T>::max();
diff --git a/libc/src/string/memory_utils/generic/builtin.h b/libc/src/string/memory_utils/generic/builtin.h
index 5239329f653b3..ba4f4b8984088 100644
--- a/libc/src/string/memory_utils/generic/builtin.h
+++ b/libc/src/string/memory_utils/generic/builtin.h
@@ -10,16 +10,16 @@
 #define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_GENERIC_BUILTIN_H
 
 #include "src/__support/macros/attributes.h" // LIBC_INLINE
-#include "src/__support/macros/config.h"     // LIBC_HAS_BUILTIN
 #include "src/string/memory_utils/utils.h"   // Ptr, CPtr
 
 #include <stddef.h> // size_t
 
 namespace LIBC_NAMESPACE {
 
-static_assert(LIBC_HAS_BUILTIN(__builtin_memcpy), "Builtin not defined");
-static_assert(LIBC_HAS_BUILTIN(__builtin_memset), "Builtin not defined");
-static_assert(LIBC_HAS_BUILTIN(__builtin_memmove), "Builtin not defined");
+#if !__has_builtin(__builtin_memcpy) || !__has_builtin(__builtin_memset) ||    \
+    !__has_builtin(__builtin_memmove)
+#error "Builtin not defined");
+#endif
 
 [[maybe_unused]] LIBC_INLINE void
 inline_memcpy_builtin(Ptr dst, CPtr src, size_t count, size_t offset = 0) {
diff --git a/libc/src/string/memory_utils/utils.h b/libc/src/string/memory_utils/utils.h
index 79526d19c6b3d..b3e1a26ad9961 100644
--- a/libc/src/string/memory_utils/utils.h
+++ b/libc/src/string/memory_utils/utils.h
@@ -14,7 +14,6 @@
 #include "src/__support/CPP/type_traits.h"
 #include "src/__support/endian.h"
 #include "src/__support/macros/attributes.h" // LIBC_INLINE
-#include "src/__support/macros/config.h"     // LIBC_HAS_BUILTIN
 #include "src/__support/macros/properties/architectures.h"
 
 #include <stddef.h> // size_t
@@ -71,11 +70,11 @@ LIBC_INLINE bool is_disjoint(const void *p1, const void *p2, size_t size) {
   return sdiff >= 0 ? size <= udiff : size <= neg_udiff;
 }
 
-#if LIBC_HAS_BUILTIN(__builtin_memcpy_inline)
+#if __has_builtin(__builtin_memcpy_inline)
 #define LLVM_LIBC_HAS_BUILTIN_MEMCPY_INLINE
 #endif
 
-#if LIBC_HAS_BUILTIN(__builtin_memset_inline)
+#if __has_builtin(__builtin_memset_inline)
 #define LLVM_LIBC_HAS_BUILTIN_MEMSET_INLINE
 #endif
 
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index 0d531a3dc12a7..ea7b625b89a50 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -216,7 +216,6 @@ libc_support_library(
         ":__support_cpp_limits",
         ":__support_cpp_type_traits",
         ":__support_macros_attributes",
-        ":__support_macros_config",
         ":__support_macros_sanitizer",
     ],
 )
@@ -383,7 +382,6 @@ libc_support_library(
     ],
     deps = [
         ":__support_macros_attributes",
-        ":__support_macros_config",
         ":__support_macros_properties_types",
         ":llvm_libc_macros_stdfix_macros",
     ],
@@ -660,7 +658,6 @@ libc_support_library(
         ":__support_cpp_limits",
         ":__support_cpp_type_traits",
         ":__support_macros_attributes",
-        ":__support_macros_config",
     ],
 )
 
@@ -2318,7 +2315,6 @@ libc_support_library(
         ":__support_cpp_cstddef",
         ":__support_cpp_type_traits",
         ":__support_macros_attributes",
-        ":__support_macros_config",
         ":__support_macros_optimization",
         ":__support_macros_properties_architectures",
         ":__support_macros_properties_cpu_features",