diff options
| -rw-r--r-- | Doc/whatsnew/3.11.rst | 6 | ||||
| -rw-r--r-- | Include/pymath.h | 31 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Build/2022-02-04-21-26-50.bpo-46640.HXUmQp.rst | 4 |
3 files changed, 20 insertions, 21 deletions
diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst index 1558d67..7b5e7da 100644 --- a/Doc/whatsnew/3.11.rst +++ b/Doc/whatsnew/3.11.rst @@ -604,6 +604,12 @@ Build Changes ``isinf()``, ``isnan()``, ``round()``. (Contributed by Victor Stinner in :issue:`45440`.) +* Building Python now requires a C99 ``<math.h>`` header file providing + a ``NAN`` constant, or the ``__builtin_nan()`` built-in function. If a + platform does not support Not-a-Number (NaN), the ``Py_NO_NAN`` macro can be + defined in the ``pyconfig.h`` file. + (Contributed by Victor Stinner in :issue:`46640`.) + * Freelists for object structs can now be disabled. A new :program:`configure` option :option:`!--without-freelists` can be used to disable all freelists except empty tuple singleton. diff --git a/Include/pymath.h b/Include/pymath.h index 57310fc..edd0841 100644 --- a/Include/pymath.h +++ b/Include/pymath.h @@ -51,29 +51,18 @@ #endif /* Py_NAN - * A value that evaluates to a NaN. On IEEE 754 platforms INF*0 or - * INF/INF works. Define Py_NO_NAN in pyconfig.h if your platform - * doesn't support NaNs. + * A value that evaluates to a quiet Not-a-Number (NaN). + * Define Py_NO_NAN in pyconfig.h if your platform doesn't support NaNs. */ #if !defined(Py_NAN) && !defined(Py_NO_NAN) -# if !defined(__INTEL_COMPILER) -# define Py_NAN (Py_HUGE_VAL * 0.) -# else /* __INTEL_COMPILER */ -# if defined(ICC_NAN_STRICT) - #pragma float_control(push) - #pragma float_control(precise, on) - #pragma float_control(except, on) - Py_NO_INLINE static double __icc_nan() - { - return sqrt(-1.0); - } - #pragma float_control (pop) -# define Py_NAN __icc_nan() -# else /* ICC_NAN_RELAXED as default for Intel Compiler */ - static const union { unsigned char buf[8]; double __icc_nan; } __nan_store = {0,0,0,0,0,0,0xf8,0x7f}; -# define Py_NAN (__nan_store.__icc_nan) -# endif /* ICC_NAN_STRICT */ -# endif /* __INTEL_COMPILER */ +# if _Py__has_builtin(__builtin_nan) + // Built-in implementation of the ISO C99 function nan(): quiet NaN. +# define Py_NAN (__builtin_nan("")) +#else + // Use C99 NAN constant: quiet Not-A-Number. + // NAN is a float, Py_NAN is a double: cast to double. +# define Py_NAN ((double)NAN) +# endif #endif #endif /* Py_PYMATH_H */ diff --git a/Misc/NEWS.d/next/Build/2022-02-04-21-26-50.bpo-46640.HXUmQp.rst b/Misc/NEWS.d/next/Build/2022-02-04-21-26-50.bpo-46640.HXUmQp.rst new file mode 100644 index 0000000..c738111 --- /dev/null +++ b/Misc/NEWS.d/next/Build/2022-02-04-21-26-50.bpo-46640.HXUmQp.rst @@ -0,0 +1,4 @@ +Building Python now requires a C99 ``<math.h>`` header file providing a ``NAN`` +constant, or the ``__builtin_nan()`` built-in function. If a platform does not +support Not-a-Number (NaN), the ``Py_NO_NAN`` macro can be defined in the +``pyconfig.h`` file. Patch by Victor Stinner. |