traverseda
/
cpython
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Use copysign to produce appropriately signed zeros instead of trying to worm around possible compiler optimizations.

This commit is contained in:
Mark Dickinson 2010-12-04 13:14:29 +00:00
parent 2cf9ddb390
commit 7b1bee47ae
1 changed files with 5 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
Objects/floatobject.c
View File

@ -609,11 +609,8 @@ float_rem(PyObject *v, PyObject *w)
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;
it has the same sign as the denominator. */
mod = copysign(0.0, wx);
}
PyFPE_END_PROTECT(mod)
return PyFloat_FromDouble(mod);
@ -649,11 +646,8 @@ float_divmod(PyObject *v, PyObject *w)
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;
it has the same sign as the denominator. */
mod = copysign(0.0, wx);
}
/* snap quotient to nearest integral value */
if (div) {
@ -663,8 +657,7 @@ float_divmod(PyObject *v, PyObject *w)
}
else {
/* div is zero - get the same sign as the true quotient */
div *= div; /* hide "div = +0" from optimizers */
floordiv = div * vx / wx; /* zero w/ sign of vx/wx */
floordiv = copysign(0.0, vx / wx); /* zero w/ sign of vx/wx */
}
PyFPE_END_PROTECT(floordiv)
return Py_BuildValue("(dd)", floordiv, mod);