[libc++] Rewrite <cmath>

[philnik]

Summary

The <cmath> implementation has a few things that I wanted to change. I originally planned to do them one at a time, but noticed that the changes essentially amount to a rewrite of the header, so I did that instead.

Specifically the changes are:

• Replacing _LIBCPP_INLINE_VISIBILITY with _LIBCPP_HIDE_FROM_ABI
• Moving the enable_ifs from the return type to a defaulted template parameter
• Removing the libcpp prefix on the argument names
• Granularizing the header
• Moving the functions into the versioned namespace
• Using builtins for the math functions

The libcpp prefix has been added for compatibility with newlib in D5080, but I think we can remove the workaround. We use __x elsewhere and newlib doesn't use __x in it's implementation since 2015 for GCC 2.97 and later. I think even older newlibs shouldn't be affected, since we don't rely on the macros from the libc with this patch.

The main functional change here is switching to builtins for all functions. This has multiple benefits:

• We can provide the full overload set of all functions without having to include the libc math.h
• We can support <cmath> during constant evaluation, even on platforms which don't have the functions implemented (once P0533R9 is implemented)
• Platforms with an incomplete implementation of math.h can use libc++ (there will be a link-time error if the functions are used instead of a compile-time error when trying to build libc++)

The main disadvantage of this patch is that it adds a double overload for all functions, but I think this is outweighed by the benefits, especially since the overloads are all just forwarding to __builtin_<function name>.

[philnik]

• Generate files

[philnik]

• try to fix CI

[philnik]

Rewrite the rest of math.h

[philnik]

• Try to fix CI

[philnik]

• Try to fix CI

[philnik]

• Fix tests

[philnik]

• Try to fix CI

[ldionne]

libcxx/include/__cmath/angular_functions.h

1 ↗

(On Diff #465723)

This change needs to be split into multiple patches that can be reviewed and validated on their own, especially since cmath and math.h interact with the C library, which makes them even more tricky. You already outlined in your commit message all the different things that this patch does, and I think each of them can be a separate patch. I know this is more work, but I think it's the only way to land this.

libcxx/include/CMakeLists.txt

set(files
   __chrono/steady_clock.h
   __chrono/system_clock.h
   __chrono/time_point.h
   __chrono/weekday.h
   __chrono/year.h
   __chrono/year_month.h
   __chrono/year_month_day.h
   __chrono/year_month_weekday.h
+  __cmath/compare.h
+  __cmath/isfinite.h
+  __cmath/isinf.h
+  __cmath/isnan.h
+  __cmath/isnormal.h
+  __cmath/signbit.h
   __compare/common_comparison_category.h
   __compare/compare_partial_order_fallback.h
   __compare/compare_strong_order_fallback.h
   __compare/compare_three_way.h
   __compare/compare_three_way_result.h
   __compare/compare_weak_order_fallback.h
   __compare/is_eq.h
   __compare/ordering.h

libcxx/include/__cmath/compare.h

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CMATH_COMPARE_H
+#define _LIBCPP___CMATH_COMPARE_H
+
+#include <__config>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_arithmetic.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+template <class _Tp,
+          class _Up,
+          std::__enable_if_t<std::is_arithmetic<_Tp>::value && std::is_arithmetic<_Up>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool isless(_Tp __lhs, _Up __rhs) _NOEXCEPT {
+  return __builtin_isless(__lhs, __rhs);
+}
+
+template <class _Tp,
+          class _Up,
+          std::__enable_if_t<std::is_arithmetic<_Tp>::value && std::is_arithmetic<_Up>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool islessequal(_Tp __lhs, _Up __rhs) _NOEXCEPT {
+  return __builtin_islessequal(__lhs, __rhs);
+}
+
+template <class _Tp,
+          class _Up,
+          std::__enable_if_t<std::is_arithmetic<_Tp>::value && std::is_arithmetic<_Up>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool islessgreater(_Tp __lhs, _Up __rhs) _NOEXCEPT {
+  return __builtin_islessgreater(__lhs, __rhs);
+}
+
+template <class _Tp,
+          class _Up,
+          std::__enable_if_t<std::is_arithmetic<_Tp>::value && std::is_arithmetic<_Up>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool isgreaterequal(_Tp __lhs, _Up __rhs) _NOEXCEPT {
+  return __builtin_isgreaterequal(__lhs, __rhs);
+}
+
+template <class _Tp,
+          class _Up,
+          std::__enable_if_t<std::is_arithmetic<_Tp>::value && std::is_arithmetic<_Up>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool isgreater(_Tp __lhs, _Up __rhs) _NOEXCEPT {
+  return __builtin_isgreater(__lhs, __rhs);
+}
+
+template <class _Tp,
+          class _Up,
+          std::__enable_if_t<std::is_arithmetic<_Tp>::value && std::is_arithmetic<_Up>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool isunordered(_Tp __lhs, _Up __rhs) _NOEXCEPT {
+  return __builtin_isunordered(__lhs, __rhs);
+}
+
+#endif // _LIBCPP___CMATH_COMPARE_H

libcxx/include/__cmath/isfinite.h

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CMATH_ISFINITE_H
+#define _LIBCPP___CMATH_ISFINITE_H
+
+#include <__config>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_arithmetic.h>
+#include <limits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+template <class _Tp,
+          std::__enable_if_t< std::is_arithmetic<_Tp>::value && std::numeric_limits<_Tp>::has_infinity, int> = 0>
+inline _LIBCPP_HIDE_FROM_ABI bool isfinite(_Tp __lcpp_x) _NOEXCEPT {
+  return __builtin_isfinite(__lcpp_x);
+}
+
+template <class _Tp,
+          std::__enable_if_t< std::is_arithmetic<_Tp>::value && !std::numeric_limits<_Tp>::has_infinity, int> = 0>
+inline _LIBCPP_HIDE_FROM_ABI bool isfinite(_Tp) _NOEXCEPT {
+  return true;
+}
+
+#endif // _LIBCPP___CMATH_ISFINITE_H

libcxx/include/__cmath/isinf.h

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CMATH_ISINF_H
+#define _LIBCPP___CMATH_ISINF_H
+
+#include <__config>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_arithmetic.h>
+#include <limits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+template <class _Tp,
+          std::__enable_if_t<std::is_arithmetic<_Tp>::value && std::numeric_limits<_Tp>::has_infinity, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool isinf(_Tp __v) _NOEXCEPT {
+  return __builtin_isinf(__v);
+}
+
+template <class _Tp,
+          std::__enable_if_t<std::is_arithmetic<_Tp>::value && !std::numeric_limits<_Tp>::has_infinity, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool isinf(_Tp) _NOEXCEPT {
+  return false;
+}
+
+#endif // _LIBCPP___CMATH_ISINF_H

libcxx/include/__cmath/isnan.h

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CMATH_ISNAN_H
+#define _LIBCPP___CMATH_ISNAN_H
+
+#include <__config>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_floating_point.h>
+#include <__type_traits/is_integral.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+template <class _Tp, std::__enable_if_t<std::is_floating_point<_Tp>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool isnan(_Tp __v) _NOEXCEPT {
+  return __builtin_isnan(__v);
+}
+
+template <class _Tp, std::__enable_if_t<std::is_integral<_Tp>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool isnan(_Tp) _NOEXCEPT {
+  return false;
+}
+
+#endif // _LIBCPP___CMATH_ISNAN_H

libcxx/include/__cmath/isnormal.h

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CMATH_ISNORMAL_H
+#define _LIBCPP___CMATH_ISNORMAL_H
+
+#include <__config>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_floating_point.h>
+#include <__type_traits/is_integral.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+template <class _Tp, std::__enable_if_t<std::is_floating_point<_Tp>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool isnormal(_Tp __v) _NOEXCEPT {
+  return __builtin_isnormal(__v);
+}
+
+template <class _Tp, std::__enable_if_t<std::is_integral<_Tp>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool isnormal(_Tp __v) _NOEXCEPT {
+  return __v != 0;
+}
+
+#endif // _LIBCPP___CMATH_ISNORMAL_H

libcxx/include/__cmath/signbit.h

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CMATH_SIGNBIT_H
+#define _LIBCPP___CMATH_SIGNBIT_H
+
+#include <__config>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_floating_point.h>
+#include <__type_traits/is_integral.h>
+#include <__type_traits/is_signed.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+template <class _Tp, std::__enable_if_t<std::is_floating_point<_Tp>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool signbit(_Tp __v) _NOEXCEPT {
+  return __builtin_signbit(__v);
+}
+
+template <class _Tp, std::__enable_if_t<std::is_integral<_Tp>::value && std::is_signed<_Tp>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool signbit(_Tp __v) _NOEXCEPT {
+  return __v < 0;
+}
+
+template <class _Tp, std::__enable_if_t<std::is_integral<_Tp>::value && !std::is_signed<_Tp>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI bool signbit(_Tp) _NOEXCEPT {
+  return false;
+}
+
+#endif // _LIBCPP___CMATH_SIGNBIT_H

libcxx/include/math.h

 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #include_next <math.h>
 
-#ifdef __cplusplus
-
-// We support including .h headers inside 'extern "C"' contexts, so switch
-// back to C++ linkage before including these C++ headers.
-extern "C++" {
+#ifdef isless
+#  undef isless
+#endif
 
-#include <__type_traits/promote.h>
-#include <limits>
-#include <stdlib.h>
-#include <type_traits>
+#ifdef islessequal
+#  undef islessequal
+#endif
 
-// signbit
+#ifdef islessgreater
+#  undef islessgreater
+#endif
 
-#ifdef signbit
+#ifdef isgreaterequal
+#  undef isgreaterequal
+#endif
 
-template <class _A1>
-_LIBCPP_INLINE_VISIBILITY
-bool
-__libcpp_signbit(_A1 __lcpp_x) _NOEXCEPT
-{
-#if __has_builtin(__builtin_signbit)
-    return __builtin_signbit(__lcpp_x);
-#else
-    return signbit(__lcpp_x);
+#ifdef isgreater
+#  undef isgreater
 #endif
-}
 
-#undef signbit
+#ifdef isunordered
+#  undef isunordered
+#endif
 
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_floating_point<_A1>::value, bool>::type
-signbit(_A1 __lcpp_x) _NOEXCEPT
-{
-    return __libcpp_signbit((typename std::__promote<_A1>::type)__lcpp_x);
-}
+#ifdef isfinite
+#  undef isfinite
+#endif
 
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<
-    std::is_integral<_A1>::value && std::is_signed<_A1>::value, bool>::type
-signbit(_A1 __lcpp_x) _NOEXCEPT
-{ return __lcpp_x < 0; }
+#ifdef isinf
+#  undef isinf
+#endif
 
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<
-    std::is_integral<_A1>::value && !std::is_signed<_A1>::value, bool>::type
-signbit(_A1) _NOEXCEPT
-{ return false; }
+#ifdef isnan
+#  undef isnan
+#endif
 
-#elif defined(_LIBCPP_MSVCRT)
+#ifdef isnormal
+#  undef isnormal
+#endif
 
-template <typename _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_floating_point<_A1>::value, bool>::type
-signbit(_A1 __lcpp_x) _NOEXCEPT
-{
-  return ::signbit(static_cast<typename std::__promote<_A1>::type>(__lcpp_x));
-}
+#ifdef signbit
+#  undef signbit
+#endif
 
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<
-    std::is_integral<_A1>::value && std::is_signed<_A1>::value, bool>::type
-signbit(_A1 __lcpp_x) _NOEXCEPT
-{ return __lcpp_x < 0; }
+#ifdef __cplusplus
 
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<
-    std::is_integral<_A1>::value && !std::is_signed<_A1>::value, bool>::type
-signbit(_A1) _NOEXCEPT
-{ return false; }
+// We support including .h headers inside 'extern "C"' contexts, so switch
+// back to C++ linkage before including these C++ headers.
+extern "C++" {
+#include <__cmath/compare.h>
+#include <__cmath/isfinite.h>
+#include <__cmath/isinf.h>
+#include <__cmath/isnan.h>
+#include <__cmath/isnormal.h>
+#include <__cmath/signbit.h>
 
-#endif // signbit
+#include <__type_traits/promote.h>
+#include <limits>
+#include <stdlib.h>
+#include <type_traits>
 
 // fpclassify
 
 #ifdef fpclassify
 
 template <class _A1>
 _LIBCPP_INLINE_VISIBILITY
 int

 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
 typename std::enable_if<std::is_integral<_A1>::value, int>::type
 fpclassify(_A1 __lcpp_x) _NOEXCEPT
 { return __lcpp_x == 0 ? FP_ZERO : FP_NORMAL; }
 
 #endif // fpclassify
 
-// isfinite
-
-#ifdef isfinite
-
-template <class _A1>
-_LIBCPP_INLINE_VISIBILITY
-bool
-__libcpp_isfinite(_A1 __lcpp_x) _NOEXCEPT
-{
-#if __has_builtin(__builtin_isfinite)
-    return __builtin_isfinite(__lcpp_x);
-#else
-    return isfinite(__lcpp_x);
-#endif
-}
-
-#undef isfinite
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<
-    std::is_arithmetic<_A1>::value && std::numeric_limits<_A1>::has_infinity,
-    bool>::type
-isfinite(_A1 __lcpp_x) _NOEXCEPT
-{
-    return __libcpp_isfinite((typename std::__promote<_A1>::type)__lcpp_x);
-}
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<
-    std::is_arithmetic<_A1>::value && !std::numeric_limits<_A1>::has_infinity,
-    bool>::type
-isfinite(_A1) _NOEXCEPT
-{ return true; }
-
-#endif // isfinite
-
-// isinf
-
-#ifdef isinf
-
-template <class _A1>
-_LIBCPP_INLINE_VISIBILITY
-bool
-__libcpp_isinf(_A1 __lcpp_x) _NOEXCEPT
-{
-#if __has_builtin(__builtin_isinf)
-    return __builtin_isinf(__lcpp_x);
-#else
-    return isinf(__lcpp_x);
-#endif
-}
-
-#undef isinf
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<
-    std::is_arithmetic<_A1>::value && std::numeric_limits<_A1>::has_infinity,
-    bool>::type
-isinf(_A1 __lcpp_x) _NOEXCEPT
-{
-    return __libcpp_isinf((typename std::__promote<_A1>::type)__lcpp_x);
-}
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<
-    std::is_arithmetic<_A1>::value && !std::numeric_limits<_A1>::has_infinity,
-    bool>::type
-isinf(_A1) _NOEXCEPT
-{ return false; }
-
-#ifdef _LIBCPP_PREFERRED_OVERLOAD
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-isinf(float __lcpp_x) _NOEXCEPT { return __libcpp_isinf(__lcpp_x); }
-
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
-bool
-isinf(double __lcpp_x) _NOEXCEPT { return __libcpp_isinf(__lcpp_x); }
-
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-isinf(long double __lcpp_x) _NOEXCEPT { return __libcpp_isinf(__lcpp_x); }
-#endif
-
-#endif // isinf
-
-// isnan
-
-#ifdef isnan
-
-template <class _A1>
-_LIBCPP_INLINE_VISIBILITY
-bool
-__libcpp_isnan(_A1 __lcpp_x) _NOEXCEPT
-{
-#if __has_builtin(__builtin_isnan)
-    return __builtin_isnan(__lcpp_x);
-#else
-    return isnan(__lcpp_x);
-#endif
-}
-
-#undef isnan
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_floating_point<_A1>::value, bool>::type
-isnan(_A1 __lcpp_x) _NOEXCEPT
-{
-    return __libcpp_isnan((typename std::__promote<_A1>::type)__lcpp_x);
-}
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_integral<_A1>::value, bool>::type
-isnan(_A1) _NOEXCEPT
-{ return false; }
-
-#ifdef _LIBCPP_PREFERRED_OVERLOAD
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-isnan(float __lcpp_x) _NOEXCEPT { return __libcpp_isnan(__lcpp_x); }
-
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
-bool
-isnan(double __lcpp_x) _NOEXCEPT { return __libcpp_isnan(__lcpp_x); }
-
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-isnan(long double __lcpp_x) _NOEXCEPT { return __libcpp_isnan(__lcpp_x); }
-#endif
-
-#endif // isnan
-
-// isnormal
-
-#ifdef isnormal
-
-template <class _A1>
-_LIBCPP_INLINE_VISIBILITY
-bool
-__libcpp_isnormal(_A1 __lcpp_x) _NOEXCEPT
-{
-#if __has_builtin(__builtin_isnormal)
-    return __builtin_isnormal(__lcpp_x);
-#else
-    return isnormal(__lcpp_x);
-#endif
-}
-
-#undef isnormal
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_floating_point<_A1>::value, bool>::type
-isnormal(_A1 __lcpp_x) _NOEXCEPT
-{
-    return __libcpp_isnormal((typename std::__promote<_A1>::type)__lcpp_x);
-}
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_integral<_A1>::value, bool>::type
-isnormal(_A1 __lcpp_x) _NOEXCEPT
-{ return __lcpp_x != 0; }
-
-#endif // isnormal
-
-// isgreater
-
-#ifdef isgreater
-
-template <class _A1, class _A2>
-_LIBCPP_INLINE_VISIBILITY
-bool
-__libcpp_isgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return isgreater(__lcpp_x, __lcpp_y);
-}
-
-#undef isgreater
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-isgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_isgreater((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif // isgreater
-
-// isgreaterequal
-
-#ifdef isgreaterequal
-
-template <class _A1, class _A2>
-_LIBCPP_INLINE_VISIBILITY
-bool
-__libcpp_isgreaterequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return isgreaterequal(__lcpp_x, __lcpp_y);
-}
-
-#undef isgreaterequal
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-isgreaterequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_isgreaterequal((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif // isgreaterequal
-
-// isless
-
-#ifdef isless
-
-template <class _A1, class _A2>
-_LIBCPP_INLINE_VISIBILITY
-bool
-__libcpp_isless(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return isless(__lcpp_x, __lcpp_y);
-}
-
-#undef isless
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-isless(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_isless((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif // isless
-
-// islessequal
-
-#ifdef islessequal
-
-template <class _A1, class _A2>
-_LIBCPP_INLINE_VISIBILITY
-bool
-__libcpp_islessequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return islessequal(__lcpp_x, __lcpp_y);
-}
-
-#undef islessequal
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-islessequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_islessequal((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif // islessequal
-
-// islessgreater
-
-#ifdef islessgreater
-
-template <class _A1, class _A2>
-_LIBCPP_INLINE_VISIBILITY
-bool
-__libcpp_islessgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return islessgreater(__lcpp_x, __lcpp_y);
-}
-
-#undef islessgreater
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-islessgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_islessgreater((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif // islessgreater
-
-// isunordered
-
-#ifdef isunordered
-
-template <class _A1, class _A2>
-_LIBCPP_INLINE_VISIBILITY
-bool
-__libcpp_isunordered(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return isunordered(__lcpp_x, __lcpp_y);
-}
-
-#undef isunordered
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-isunordered(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_isunordered((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif // isunordered
-
 // abs
 //
 // handled in stdlib.h
 
 // div
 //
 // handled in stdlib.h
 

libcxx/include/module.modulemap.in

module compat {
     module clocale {
       @requires_LIBCXX_ENABLE_LOCALIZATION@
       header "clocale"
       export *
     }
     module cmath {
       header "cmath"
       export *
+
+      module __cmath {
+        module compare  { private header "__cmath/compare.h" }
+        module isfinite { private header "__cmath/isfinite.h" }
+        module isinf    { private header "__cmath/isinf.h" }
+        module isnan    { private header "__cmath/isnan.h" }
+        module isnormal { private header "__cmath/isnormal.h" }
+        module signbit  { private header "__cmath/signbit.h" }
+      }
     }
     module csetjmp {
       header "csetjmp"
       export *
     }
     module csignal {
       header "csignal"
       export *