From 69468146b4ed8a92d63b22c91db7c1832dd49a78 Mon Sep 17 00:00:00 2001
From: Raymond Hettinger <python@rcn.com>
Date: Sat, 20 Jul 2013 10:56:58 -0700
Subject: Issue #18513: Add workaround for OS X 10.8 cexp bug that leads to
 wrong cmath.rect(0.0,-0.0) results.

---
 Misc/NEWS             | 3 +++
 Modules/cmathmodule.c | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/Misc/NEWS b/Misc/NEWS
index 5283da6..87a4ec5 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -28,6 +28,9 @@ Library
 
 - Issue #18455: multiprocessing should not retry connect() with same socket.
 
+- Issue #18513: Fix behaviour of cmath.rect w.r.t. signed zeros on OS X 10.8 +
+  gcc.
+
 - Issue #18101: Tcl.split() now process Unicode strings nested in a tuple as it
   do with byte strings.
 
diff --git a/Modules/cmathmodule.c b/Modules/cmathmodule.c
index 0dc6bdb..5720678 100644
--- a/Modules/cmathmodule.c
+++ b/Modules/cmathmodule.c
@@ -1006,6 +1006,13 @@ cmath_rect(PyObject *self, PyObject *args)
         else
             errno = 0;
     }
+    else if (phi == 0.0) {
+        /* Workaround for buggy results with phi=-0.0 on OS X 10.8.  See
+           bugs.python.org/issue18513. */
+        z.real = r;
+        z.imag = r * phi;
+        errno = 0;
+    }
     else {
         z.real = r * cos(phi);
         z.imag = r * sin(phi);
-- 
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