gh-104263: Rely on Py_NAN and introduce Py_INFINITY (GH-104202)

This PR removes `_Py_dg_stdnan` and `_Py_dg_infinity` in favour of
using the standard `NAN` and `INFINITY` macros provided by C99.
This change has the side-effect of fixing a bug on MIPS where the
hard-coded value used by `_Py_dg_stdnan` gave a signalling NaN
rather than a quiet NaN.
---------

Co-authored-by: Mark Dickinson <dickinsm@gmail.com>

1 files changed, 1 insertions, 12 deletions

diff --git a/Objects/floatobject.c b/Objects/floatobject.c
index d257857..83a263c 100644
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -2424,25 +2424,14 @@ PyFloat_Unpack2(const char *data, int le)
     f |= *p;
 
     if (e == 0x1f) {
-#if _PY_SHORT_FLOAT_REPR == 0
         if (f == 0) {
             /* Infinity */
             return sign ? -Py_HUGE_VAL : Py_HUGE_VAL;
         }
         else {
             /* NaN */
-            return sign ? -Py_NAN : Py_NAN;
+            return sign ? -fabs(Py_NAN) : fabs(Py_NAN);
         }
-#else  // _PY_SHORT_FLOAT_REPR == 1
-        if (f == 0) {
-            /* Infinity */
-            return _Py_dg_infinity(sign);
-        }
-        else {
-            /* NaN */
-            return _Py_dg_stdnan(sign);
-        }
-#endif  // _PY_SHORT_FLOAT_REPR == 1
     }
 
     x = (double)f / 1024.0;