From 9457fd952cafc701375fc9fae575a4aca1374de3 Mon Sep 17 00:00:00 2001
From: Joseph Myers <joseph@codesourcery.com>
Date: Fri, 26 Apr 2013 19:26:22 +0000
Subject: Fix catan, catanh missing underflows (bug 15406).

---
 math/s_catan.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

(limited to 'math/s_catan.c')

diff --git a/math/s_catan.c b/math/s_catan.c
index 783941a..6a1016e 100644
--- a/math/s_catan.c
+++ b/math/s_catan.c
@@ -20,7 +20,7 @@
 #include <complex.h>
 #include <math.h>
 #include <math_private.h>
-
+#include <float.h>
 
 __complex__ double
 __catan (__complex__ double x)
@@ -83,6 +83,17 @@ __catan (__complex__ double x)
 	  num = 4.0 * __imag__ x;
 	  __imag__ res = 0.25 * __log1p (num / den);
 	}
+
+      if (fabs (__real__ res) < DBL_MIN)
+	{
+	  volatile double force_underflow = __real__ res * __real__ res;
+	  (void) force_underflow;
+	}
+      if (fabs (__imag__ res) < DBL_MIN)
+	{
+	  volatile double force_underflow = __imag__ res * __imag__ res;
+	  (void) force_underflow;
+	}
     }
 
   return res;
-- 
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