Index: include/math.h
===================================================================
--- include/math.h
+++ include/math.h
@@ -766,6 +766,14 @@
 inline _LIBCPP_INLINE_VISIBILITY
 long double
 abs(long double __lcpp_x) _NOEXCEPT {return ::fabsl(__lcpp_x);}
+    
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<
+    std::is_integral<_A1>::value &&
+    !std::is_unsigned<_A1>::value, // allows for long long int, long int, int
+_A1>::type
+abs(_A1 __lcpp_x) _NOEXCEPT {return abs(__lcpp_x);}
 #endif // !(defined(_AIX) || defined(__sun__))
 
 // acos
Index: test/libcxx/numerics/c.math/abs.fail.cpp
===================================================================
--- /dev/null
+++ test/libcxx/numerics/c.math/abs.fail.cpp
@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <cstdlib>
+
+#include "test_macros.h"
+
+#ifndef _LIBCPP_VERSION
+#error _LIBCPP_VERSION not defined
+#endif
+
+int main()
+{
+    unsigned int ui = -5;
+    std::abs(ui); // unsigned types are not allowed
+    
+    long long double lld = -10;
+    std::abs(lld); // no overload and not `is_integral`
+    
+    return 0;
+}
+
Index: test/libcxx/numerics/c.math/abs.pass.cpp
===================================================================
--- /dev/null
+++ test/libcxx/numerics/c.math/abs.pass.cpp
@@ -0,0 +1,52 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <math.h>
+#include <assert.h>
+
+#include "test_macros.h"
+
+#ifndef _LIBCPP_VERSION
+#error _LIBCPP_VERSION not defined
+#endif
+
+template <class T>
+void test_abs()
+{
+    T val = -5;
+    T pos_val = 5;
+    
+    assert(abs(val) == 5);
+    assert(abs(pos_val) == 5);
+    
+    ASSERT_SAME_TYPE(decltype(abs(val)), T);
+}
+
+void test_big()
+{
+    long long int big_value = 9223372036854775800; // a value to big for ints to store
+    long long int negative_big_value = -big_value;
+    assert(abs(negative_big_value) == big_value); // make sure it doesnt get casted to a smaller type
+}
+
+int main()
+{
+    test_abs<int>();
+    test_abs<long int>();
+    test_abs<long long int>();
+    test_abs<long double>();
+    test_abs<double>();
+    test_abs<float>();
+    test_abs<short int>();
+    test_abs<char>();
+    
+    test_big();
+    
+    return 0;
+}
+