[libc][math] Add POSIX math constants to math.h header.

libc/include/llvm-libc-macros/math-macros.h

@@ -50,4 +50,105 @@
 #define math_errhandling (MATH_ERRNO | MATH_ERREXCEPT)
 #endif
 
+// POSIX math constants
+// https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/math.h.html
+#define M_E (__extension__ 0x1.5bf0a8b145769p1)
+#define M_EGAMMA (__extension__ 0x1.2788cfc6fb619p-1)
+#define M_LOG2E (__extension__ 0x1.71547652b82fep0)
+#define M_LOG10E (__extension__ 0x1.bcb7b1526e50ep-2)
+#define M_LN2 (__extension__ 0x1.62e42fefa39efp-1)
+#define M_LN10 (__extension__ 0x1.26bb1bbb55516p1)
+#define M_PHI (__extension__ 0x1.9e3779b97f4a8p0)
+#define M_PI (__extension__ 0x1.921fb54442d18p1)
+#define M_PI_2 (__extension__ 0x1.921fb54442d18p0)
+#define M_PI_4 (__extension__ 0x1.921fb54442d18p-1)
+#define M_1_PI (__extension__ 0x1.45f306dc9c883p-2)
+#define M_1_SQRTPI (__extension__ 0x1.20dd750429b6dp-1)
+#define M_2_PI (__extension__ 0x1.45f306dc9c883p-1)
+#define M_2_SQRTPI (__extension__ 0x1.20dd750429b6dp0)
+#define M_SQRT2 (__extension__ 0x1.6a09e667f3bcdp0)
+#define M_SQRT3 (__extension__ 0x1.bb67ae8584caap0)
+#define M_SQRT1_2 (__extension__ 0x1.6a09e667f3bcdp-1)
+#define M_SQRT1_3 (__extension__ 0x1.279a74590331cp-1)
+
+#define M_Ef (__extension__ 0x1.5bf0a8p1f)
+#define M_EGAMMAf (__extension__ 0x1.2788dp-1f)
+#define M_LOG2Ef (__extension__ 0x1.715476p0f)
+#define M_LOG10Ef (__extension__ 0x1.bcb7b2p-2f)
+#define M_LN2f (__extension__ 0x1.62e43p-1f)
+#define M_LN10f (__extension__ 0x1.26bb1cp1f)
+#define M_PHIf (__extension__ 0x1.9e377ap0f)
+#define M_PIf (__extension__ 0x1.921fb6p1f)
+#define M_PI_2f (__extension__ 0x1.921fb6p0f)
+#define M_PI_4f (__extension__ 0x1.921fb6p-1f)
+#define M_1_PIf (__extension__ 0x1.45f306p-2f)
+#define M_1_SQRTPIf (__extension__ 0x1.20dd76p-1f)
+#define M_2_PIf (__extension__ 0x1.45f306p-1f)
+#define M_2_SQRTPIf (__extension__ 0x1.20dd76p0f)
+#define M_SQRT2f (__extension__ 0x1.6a09e6p0f)
+#define M_SQRT3f (__extension__ 0x1.bb67aep0f)
+#define M_SQRT1_2f (__extension__ 0x1.6a09e6p-1f)
+#define M_SQRT1_3f (__extension__ 0x1.279a74p-1f)
+
+#define M_El (__extension__ 0x1.5bf0a8b1457695355fb8ac404e7ap1L)
+#define M_EGAMMAl (__extension__ 0x1.2788cfc6fb618f49a37c7f0202a6p-1L)
+#define M_LOG2El (__extension__ 0x1.71547652b82fe1777d0ffda0d23ap0L)
+#define M_LOG10El (__extension__ 0x1.bcb7b1526e50e32a6ab7555f5a68p-2L)
+#define M_LN2l (__extension__ 0x1.62e42fefa39ef35793c7673007e6p-1L)
+#define M_LN10l (__extension__ 0x1.26bb1bbb5551582dd4adac5705a6p1L)
+#define M_PHIl (__extension__ 0x1.9e3779b97f4a7c15f39cc0605ceep0L)
+#define M_PIl (__extension__ 0x1.921fb54442d18469898cc51701b8p1L)
+#define M_PI_2l (__extension__ 0x1.921fb54442d18469898cc51701b8p0L)
+#define M_PI_4l (__extension__ 0x1.921fb54442d18469898cc51701b8p-1L)
+#define M_1_PIl (__extension__ 0x1.45f306dc9c882a53f84eafa3ea6ap-2L)
+#define M_1_SQRTPIl (__extension__ 0x1.20dd750429b6d11ae3a914fed7fep-1L)
+#define M_2_PIl (__extension__ 0x1.45f306dc9c882a53f84eafa3ea6ap-1L)
+#define M_2_SQRTPIl (__extension__ 0x1.20dd750429b6d11ae3a914fed7fep0L)
+#define M_SQRT2l (__extension__ 0x1.6a09e667f3bcc908b2fb1366ea95p0L)
+#define M_SQRT3l (__extension__ 0x1.bb67ae8584caa73b25742d7078b8p0L)
+#define M_SQRT1_2l (__extension__ 0x1.6a09e667f3bcc908b2fb1366ea95p-1L)
+#define M_SQRT1_3l (__extension__ 0x1.279a74590331c4d218f81e4afb25p-1L)
+
+#ifdef __FLT16_MANT_DIG__
+#define M_Ef16 (__extension__ 0x1.5cp1f16)
+#define M_EGAMMAf16 (__extension__ 0x1.278p-1f16)
+#define M_LOG2Ef16 (__extension__ 0x1.714f16)
+#define M_LOG10Ef16 (__extension__ 0x1.bccp-2f16)
+#define M_LN2f16 (__extension__ 0x1.63p-1f16)
+#define M_LN10f16 (__extension__ 0x1.26cp1f16)
+#define M_PHIf16 (__extension__ 0x1.9e4p0f16)
+#define M_PIf16 (__extension__ 0x1.92p1f16)
+#define M_PI_2f16 (__extension__ 0x1.92p0f16)
+#define M_PI_4f16 (__extension__ 0x1.92p-1f16)
+#define M_1_PIf16 (__extension__ 0x1.46p-2f16)
+#define M_1_SQRTPIf16 (__extension__ 0x1.20cp-1f16)
+#define M_2_PIf16 (__extension__ 0x1.46p-1f16)
+#define M_2_SQRTPIf16 (__extension__ 0x1.20cp0f16)
+#define M_SQRT2f16 (__extension__ 0x1.6ap0f16)
+#define M_SQRT3f16 (__extension__ 0x1.bb8p0f16)
+#define M_SQRT1_2f16 (__extension__ 0x1.6ap-1f16)
+#define M_SQRT1_3f16 (__extension__ 0x1.278p-1f16)
+#endif // __FLT16_MANT_DIG__
+
+#ifdef __SIZEOF_FLOAT128__
+#define M_Ef128 (__extension__ 0x1.5bf0a8b1457695355fb8ac404e7ap1q)
+#define M_EGAMMAf128 (__extension__ 0x1.2788cfc6fb618f49a37c7f0202a6p-1q)
+#define M_LOG2Ef128 (__extension__ 0x1.71547652b82fe1777d0ffda0d23ap0q)
+#define M_LOG10Ef128 (__extension__ 0x1.bcb7b1526e50e32a6ab7555f5a68p-2q)
+#define M_LN2f128 (__extension__ 0x1.62e42fefa39ef35793c7673007e6p-1q)
+#define M_LN10f128 (__extension__ 0x1.26bb1bbb5551582dd4adac5705a6p1q)
+#define M_PHIf128 (__extension__ 0x1.9e3779b97f4a7c15f39cc0605ceep0q)
+#define M_PIf128 (__extension__ 0x1.921fb54442d18469898cc51701b8p1q)
+#define M_PI_2f128 (__extension__ 0x1.921fb54442d18469898cc51701b8p0q)
+#define M_PI_4f128 (__extension__ 0x1.921fb54442d18469898cc51701b8p-1q)
+#define M_1_PIf128 (__extension__ 0x1.45f306dc9c882a53f84eafa3ea6ap-2q)
+#define M_1_SQRTPIf128 (__extension__ 0x1.20dd750429b6d11ae3a914fed7fep-1q)
+#define M_2_PIf128 (__extension__ 0x1.45f306dc9c882a53f84eafa3ea6ap-1q)
+#define M_2_SQRTPIf128 (__extension__ 0x1.20dd750429b6d11ae3a914fed7fep0q)
+#define M_SQRT2f128 (__extension__ 0x1.6a09e667f3bcc908b2fb1366ea95p0q)
+#define M_SQRT3f128 (__extension__ 0x1.bb67ae8584caa73b25742d7078b8p0q)
+#define M_SQRT1_2f128 (__extension__ 0x1.6a09e667f3bcc908b2fb1366ea95p-1q)
+#define M_SQRT1_3f128 (__extension__ 0x1.279a74590331c4d218f81e4afb25p-1q)
+#endif // __SIZEOF_FLOAT128__
+
 #endif // LLVM_LIBC_MACROS_MATH_MACROS_H

libc/test/include/CMakeLists.txt

@@ -484,6 +484,21 @@ add_libc_test(
     libc.include.llvm-libc-macros.math_function_macros
 )
 
+add_libc_test(
+  math_constants_c_test
+  C_TEST
+  UNIT_TEST_ONLY
+  SUITE
+    libc_include_tests
+  SRCS
+    math_constants_test.c
+  COMPILE_OPTIONS
+    -Wall
+    -Werror
+  DEPENDS
+    libc.include.llvm-libc-macros.math_macros
+)
+
 # Test `#include <...>` of each header in each available language mode.
 # This is gated on -DLLVM_LIBC_BUILD_HEADER_TESTS=ON until all the bugs
 # in headers are fixed so the tests all compile.

libc/test/include/math_constants_test.c

@@ -0,0 +1,23 @@
+//===-- Unittests for math constants --------------------------------------===//
+//
+// 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 "include/llvm-libc-macros/math-macros.h"
+
+#define IS_DOUBLE(X) _Generic((X), double: 1, default: 0)
+
+#define IS_FLOAT(X) _Generic((X), float: 1, default: 0)
+
+// check if macro is defined
+#ifndef M_PI
+#error "M_PI macro is not defined"
+#else
+int main(void) {
+  _Static_assert(IS_DOUBLE(M_PI), "M_PI is not of double type.");
+  _Static_assert(IS_FLOAT(M_PIf), "M_PIf is not of float type.");
+  return 0;
+}
+#endif