Index: Include/floatobject.h
===================================================================
--- Include/floatobject.h	(revision 67706)
+++ Include/floatobject.h	(working copy)
@@ -32,6 +32,15 @@
 		return PyFloat_FromDouble(-Py_HUGE_VAL);	\
 	} while(0)
 
+/* Py_FORCE_DOUBLE is used to force a possibly extended precision value to
+ double precision; this is useful on x86 systems that make use of the x87
+ FPU. See Modules/cmathmodule.c for an example of its use. On non x86
+ systems it wouldn't be a problem if Py_FORCE_DOUBLE did nothing.*/
+PyAPI_FUNC(double) Py_force_double(double);
+#ifndef Py_FORCE_DOUBLE
+#define Py_FORCE_DOUBLE(x) Py_force_double(x)
+#endif
+
 PyAPI_FUNC(double) PyFloat_GetMax(void);
 PyAPI_FUNC(double) PyFloat_GetMin(void);
 PyAPI_FUNC(PyObject *) PyFloat_GetInfo(void);
Index: Objects/floatobject.c
===================================================================
--- Objects/floatobject.c	(revision 67706)
+++ Objects/floatobject.c	(working copy)
@@ -57,6 +57,18 @@
 	return p + N_FLOATOBJECTS - 1;
 }
 
+/* This function (Py_force_double) doesn't really belong here: it's needed
+ in the math and cmath modules, but we put it in a different file to stop an
+ optimizing compiler from inlining it. */
+
+/* force a (possibly extended precision) value into memory, thereby
+ rounding to double precision */
+double Py_force_double(double x)
+{
+	volatile double y = x;
+	return y;
+}
+
 double
 PyFloat_GetMax(void)
 {
Index: Modules/cmathmodule.c
===================================================================
--- Modules/cmathmodule.c	(revision 67706)
+++ Modules/cmathmodule.c	(working copy)
@@ -478,7 +478,8 @@
 		r.imag = l*sin(z.imag);
 	}
 	/* detect overflow, and set errno accordingly */
-	if (Py_IS_INFINITY(r.real) || Py_IS_INFINITY(r.imag))
+	if (Py_IS_INFINITY(Py_FORCE_DOUBLE(r.real)) ||
+	 Py_IS_INFINITY(Py_FORCE_DOUBLE(r.imag)))
 		errno = ERANGE;
 	else
 		errno = 0;
</div><div class="naked_ctrl">
<form action="/index.cgi/contrast" method="get" name="gate">
<p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="https://bugs.python.org/file12355/force_to_memory2.patch">(-&gt;オリジナル)</a>
/ <label>アドレス: <input type="text" name="naked_post_url" value="https://bugs.python.org/file12355/force_to_memory2.patch" size="22" /></label> <label>モード: <select name="naked_post_mode">
<option value="default">デフォルト</option>
<option value="speech">音声ブラウザ</option>
<option value="ruby">ルビ付き</option>
<option value="contrast" selected="selected">配色反転</option>
<option value="larger-text">文字拡大</option>
<option value="mobile">モバイル</option>
</select>
<input type="submit" value="表示" />
</p>
</form>
</div>