Backout broken backport. (Sorry.)
diff --git a/Objects/floatobject.c b/Objects/floatobject.c
index 6a2af74..865c960 100644
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -600,20 +600,10 @@
#endif
PyFPE_START_PROTECT("modulo", return 0)
mod = fmod(vx, wx);
- if (mod) {
- /* ensure the remainder has the same sign as the denominator */
- if ((wx < 0) != (mod < 0)) {
- mod += wx;
- }
- }
- else {
- /* the remainder is zero, and in the presence of signed zeroes
- fmod returns different results across platforms; ensure
- it has the same sign as the denominator; we'd like to do
- "mod = wx * 0.0", but that may get optimized away */
- mod *= mod; /* hide "mod = +0" from optimizer */
- if (wx < 0.0)
- mod = -mod;
+ /* note: checking mod*wx < 0 is incorrect -- underflows to
+ 0 if wx < sqrt(smallest nonzero double) */
+ if (mod && ((wx < 0) != (mod < 0))) {
+ mod += wx;
}
PyFPE_END_PROTECT(mod)
return PyFloat_FromDouble(mod);