MAINT: npymath cleanups for isnan, isinf, isinfinite, signbit, nextafter (#22684)

* make isnan, isinf, isfinite, signbit, nextafter aliases

* fixes from review

Co-authored-by: Sebastian Berg <sebastianb@nvidia.com>

8 files changed, 10 insertions, 195 deletions

diff --git a/numpy/core/config.h.in b/numpy/core/config.h.in
index f4ccdcd94..a47968a7d 100644
--- a/numpy/core/config.h.in
+++ b/numpy/core/config.h.in
@@ -52,11 +52,6 @@
 #mesondefine HAVE_ATTRIBUTE_TARGET_AVX512F_WITH_INTRINSICS
 #mesondefine HAVE_ATTRIBUTE_TARGET_AVX512_SKX_WITH_INTRINSICS
 
-#mesondefine HAVE_DECL_ISNAN
-#mesondefine HAVE_DECL_ISINF
-#mesondefine HAVE_DECL_ISFINITE
-#mesondefine HAVE_DECL_SIGNBIT
-
 /* C99 complex support and complex.h are not universal */
 #mesondefine HAVE_COMPLEX_H
 #mesondefine HAVE_CABS
diff --git a/numpy/core/include/numpy/_numpyconfig.h.in b/numpy/core/include/numpy/_numpyconfig.h.in
index 8e799971a..a21820026 100644
--- a/numpy/core/include/numpy/_numpyconfig.h.in
+++ b/numpy/core/include/numpy/_numpyconfig.h.in
@@ -14,10 +14,6 @@
 #mesondefine NPY_SIZEOF_PY_LONG_LONG
 #mesondefine NPY_SIZEOF_LONGLONG
 
-#mesondefine NPY_HAVE_DECL_ISNAN
-#mesondefine NPY_HAVE_DECL_ISINF
-#mesondefine NPY_HAVE_DECL_ISFINITE
-#mesondefine NPY_HAVE_DECL_SIGNBIT
 #mesondefine NPY_USE_C99_COMPLEX
 #mesondefine NPY_HAVE_COMPLEX_DOUBLE
 #mesondefine NPY_HAVE_COMPLEX_FLOAT
diff --git a/numpy/core/include/numpy/npy_math.h b/numpy/core/include/numpy/npy_math.h
index d7c9fbb4f..a1fd11396 100644
--- a/numpy/core/include/numpy/npy_math.h
+++ b/numpy/core/include/numpy/npy_math.h
@@ -195,6 +195,7 @@ NPY_INPLACE double npy_atan2(double x, double y);
 #define npy_sqrt sqrt
 #define npy_pow pow
 #define npy_modf modf
+#define npy_nextafter nextafter
 
 #if defined(__arm64__) && defined(__APPLE__)
 /* due to a build problem with scipy, export these as functions */
@@ -206,11 +207,11 @@ NPY_INPLACE double npy_log1p(double x);
 #define npy_copysign copysign
 #define npy_log1p log1p
 #endif
-double npy_nextafter(double x, double y);
+
 double npy_spacing(double x);
 
 /*
- * IEEE 754 fpu handling. Those are guaranteed to be macros
+ * IEEE 754 fpu handling
  */
 
 /* use builtins to avoid function calls in tight loops
@@ -218,11 +219,7 @@ double npy_spacing(double x);
 #ifdef HAVE___BUILTIN_ISNAN
     #define npy_isnan(x) __builtin_isnan(x)
 #else
-    #ifndef NPY_HAVE_DECL_ISNAN
-        #define npy_isnan(x) ((x) != (x))
-    #else
-        #define npy_isnan(x) isnan(x)
-    #endif
+    #define npy_isnan(x) isnan(x)
 #endif
 
 
@@ -230,39 +227,17 @@ double npy_spacing(double x);
 #ifdef HAVE___BUILTIN_ISFINITE
     #define npy_isfinite(x) __builtin_isfinite(x)
 #else
-    #ifndef NPY_HAVE_DECL_ISFINITE
-        #ifdef _MSC_VER
-            #define npy_isfinite(x) _finite((x))
-        #else
-            #define npy_isfinite(x) !npy_isnan((x) + (-x))
-        #endif
-    #else
-        #define npy_isfinite(x) isfinite((x))
-    #endif
+    #define npy_isfinite(x) isfinite((x))
 #endif
 
 /* only available if npy_config.h is available (= numpys own build) */
 #ifdef HAVE___BUILTIN_ISINF
     #define npy_isinf(x) __builtin_isinf(x)
 #else
-    #ifndef NPY_HAVE_DECL_ISINF
-        #define npy_isinf(x) (!npy_isfinite(x) && !npy_isnan(x))
-    #else
-        #define npy_isinf(x) isinf((x))
-    #endif
+    #define npy_isinf(x) isinf((x))
 #endif
 
-#ifndef NPY_HAVE_DECL_SIGNBIT
-    int _npy_signbit_f(float x);
-    int _npy_signbit_d(double x);
-    int _npy_signbit_ld(long double x);
-    #define npy_signbit(x) \
-        (sizeof (x) == sizeof (long double) ? _npy_signbit_ld (x) \
-         : sizeof (x) == sizeof (double) ? _npy_signbit_d (x) \
-         : _npy_signbit_f (x))
-#else
-    #define npy_signbit(x) signbit((x))
-#endif
+#define npy_signbit(x) signbit((x))
 
 /*
  * float C99 math funcs that need fixups or are blocklist-able
@@ -305,8 +280,8 @@ NPY_INPLACE float npy_modff(float x, float* y);
 #define npy_frexpf frexpf
 #define npy_ldexpf ldexpf
 #define npy_copysignf copysignf
+#define npy_nextafterf nextafterf
 
-float npy_nextafterf(float x, float y);
 float npy_spacingf(float x);
 
 /*
@@ -349,8 +324,8 @@ NPY_INPLACE npy_longdouble npy_modfl(npy_longdouble x, npy_longdouble* y);
 #define npy_frexpl frexpl
 #define npy_ldexpl ldexpl
 #define npy_copysignl copysignl
+#define npy_nextafterl nextafterl
 
-npy_longdouble npy_nextafterl(npy_longdouble x, npy_longdouble y);
 npy_longdouble npy_spacingl(npy_longdouble x);
 
 /*
diff --git a/numpy/core/meson.build b/numpy/core/meson.build
index 507d0868d..2b23d3f14 100644
--- a/numpy/core/meson.build
+++ b/numpy/core/meson.build
@@ -459,7 +459,6 @@ npymath_sources = [
   src_file.process('src/npymath/ieee754.c.src'),
   src_file.process('src/npymath/npy_math_complex.c.src'),
   npy_math_internal_h,
-  'src/npymath/_signbit.c',
   'src/npymath/halffloat.c',
   'src/npymath/npy_math.c',
 ]
diff --git a/numpy/core/setup.py b/numpy/core/setup.py
index 9a3b41637..4001f7ab0 100644
--- a/numpy/core/setup.py
+++ b/numpy/core/setup.py
@@ -60,14 +60,6 @@ class CallOnceOnly:
             out = copy.deepcopy(pickle.loads(self._check_types))
         return out
 
-    def check_ieee_macros(self, *a, **kw):
-        if self._check_ieee_macros is None:
-            out = check_ieee_macros(*a, **kw)
-            self._check_ieee_macros = pickle.dumps(out)
-        else:
-            out = copy.deepcopy(pickle.loads(self._check_ieee_macros))
-        return out
-
     def check_complex(self, *a, **kw):
         if self._check_complex is None:
             out = check_complex(*a, **kw)
@@ -293,43 +285,6 @@ def check_complex(config, mathlibs):
 
     return priv, pub
 
-def check_ieee_macros(config):
-    priv = []
-    pub = []
-
-    macros = []
-
-    def _add_decl(f):
-        priv.append(fname2def("decl_%s" % f))
-        pub.append('NPY_%s' % fname2def("decl_%s" % f))
-
-    # XXX: hack to circumvent cpp pollution from python: python put its
-    # config.h in the public namespace, so we have a clash for the common
-    # functions we test. We remove every function tested by python's
-    # autoconf, hoping their own test are correct
-    _macros = ["isnan", "isinf", "signbit", "isfinite"]
-    for f in _macros:
-        py_symbol = fname2def("decl_%s" % f)
-        already_declared = config.check_decl(py_symbol,
-                headers=["Python.h", "math.h"])
-        if already_declared:
-            if config.check_macro_true(py_symbol,
-                    headers=["Python.h", "math.h"]):
-                pub.append('NPY_%s' % fname2def("decl_%s" % f))
-        else:
-            macros.append(f)
-    # Normally, isnan and isinf are macro (C99), but some platforms only have
-    # func, or both func and macro version. Check for macro only, and define
-    # replacement ones if not found.
-    # Note: including Python.h is necessary because it modifies some math.h
-    # definitions
-    for f in macros:
-        st = config.check_decl(f, headers=["Python.h", "math.h"])
-        if st:
-            _add_decl(f)
-
-    return priv, pub
-
 def check_types(config_cmd, ext, build_dir):
     private_defines = []
     public_defines = []
@@ -510,7 +465,6 @@ def configuration(parent_package='',top_path=None):
             moredefs.append(('MATHLIB', ','.join(mathlibs)))
 
             check_math_capabilities(config_cmd, ext, moredefs, mathlibs)
-            moredefs.extend(cocache.check_ieee_macros(config_cmd)[0])
             moredefs.extend(cocache.check_complex(config_cmd, mathlibs)[0])
 
             # Signal check
@@ -629,7 +583,6 @@ def configuration(parent_package='',top_path=None):
                 moredefs.append(('NPY_NO_SMP', 0))
 
             mathlibs = check_mathlib(config_cmd)
-            moredefs.extend(cocache.check_ieee_macros(config_cmd)[1])
             moredefs.extend(cocache.check_complex(config_cmd, mathlibs)[1])
 
             if NPY_RELAXED_STRIDES_DEBUG:
@@ -710,8 +663,7 @@ def configuration(parent_package='',top_path=None):
 
     config.numpy_include_dirs.extend(config.paths('include'))
 
-    deps = [join('src', 'npymath', '_signbit.c'),
-            join('include', 'numpy', '*object.h'),
+    deps = [join('include', 'numpy', '*object.h'),
             join(codegen_dir, 'genapi.py'),
             ]
 
diff --git a/numpy/core/src/npymath/_signbit.c b/numpy/core/src/npymath/_signbit.c
deleted file mode 100644
index 12af55387..000000000
--- a/numpy/core/src/npymath/_signbit.c
+++ /dev/null
@@ -1,32 +0,0 @@
-/* Adapted from cephes */
-
-int
-_npy_signbit_d(double x)
-{
-    union
-    {
-        double d;
-        short s[4];
-        int i[2];
-    } u;
-
-    u.d = x;
-
-#if NPY_SIZEOF_INT == 4
-
-#ifdef WORDS_BIGENDIAN /* defined in pyconfig.h */
-    return u.i[0] < 0;
-#else
-    return u.i[1] < 0;
-#endif
-
-#else  /* NPY_SIZEOF_INT != 4 */
-
-#ifdef WORDS_BIGENDIAN
-    return u.s[0] < 0;
-#else
-    return u.s[3] < 0;
-#endif
-
-#endif  /* NPY_SIZEOF_INT */
-}
diff --git a/numpy/core/src/npymath/ieee754.c.src b/numpy/core/src/npymath/ieee754.c.src
index 5d8cb06a4..8fccc9a69 100644
--- a/numpy/core/src/npymath/ieee754.c.src
+++ b/numpy/core/src/npymath/ieee754.c.src
@@ -15,20 +15,6 @@
 #define LDBL_TRUE_MIN __LDBL_DENORM_MIN__
 #endif
 
-#if !defined(HAVE_DECL_SIGNBIT)
-#include "_signbit.c"
-
-int _npy_signbit_f(float x)
-{
-    return _npy_signbit_d((double) x);
-}
-
-int _npy_signbit_ld(long double x)
-{
-    return _npy_signbit_d((double) x);
-}
-#endif
-
 /*
  * FIXME: There is a lot of redundancy between _next* and npy_nextafter*.
  * refactor this at some point
@@ -326,25 +312,6 @@ static npy_longdouble _nextl(npy_longdouble x, int p)
 }
 /**end repeat**/
 
-/*
- * Decorate all the math functions which are available on the current platform
- */
-
-float npy_nextafterf(float x, float y)
-{
-    return nextafterf(x, y);
-}
-
-double npy_nextafter(double x, double y)
-{
-    return nextafter(x, y);
-}
-
-npy_longdouble npy_nextafterl(npy_longdouble x, npy_longdouble y)
-{
-    return nextafterl(x, y);
-}
-
 int npy_clear_floatstatus() {
     char x=0;
     return npy_clear_floatstatus_barrier(&x);
diff --git a/numpy/core/src/npymath/ieee754.cpp b/numpy/core/src/npymath/ieee754.cpp
index ebc1dbeba..1c59bf300 100644
--- a/numpy/core/src/npymath/ieee754.cpp
+++ b/numpy/core/src/npymath/ieee754.cpp
@@ -17,21 +17,6 @@
 #define LDBL_TRUE_MIN __LDBL_DENORM_MIN__
 #endif
 
-#if !defined(HAVE_DECL_SIGNBIT)
-#include "_signbit.c"
-
-int
-_npy_signbit_f(float x)
-{
-    return _npy_signbit_d((double)x);
-}
-
-int
-_npy_signbit_ld(long double x)
-{
-    return _npy_signbit_d((double)x);
-}
-#endif
 
 /*
  * FIXME: There is a lot of redundancy between _next* and npy_nextafter*.
@@ -388,28 +373,6 @@ npy_spacingl(npy_longdouble x)
 }
 }
 
-/*
- * Decorate all the math functions which are available on the current platform
- */
-
-extern "C" float
-npy_nextafterf(float x, float y)
-{
-    return nextafterf(x, y);
-}
-
-extern "C" double
-npy_nextafter(double x, double y)
-{
-    return nextafter(x, y);
-}
-
-extern "C" npy_longdouble
-npy_nextafterl(npy_longdouble x, npy_longdouble y)
-{
-    return nextafterl(x, y);
-}
-
 extern "C" int
 npy_clear_floatstatus()
 {