From 8cf28c5ebe7b02e769a3f3082fd390e6d8c11542 Mon Sep 17 00:00:00 2001
From: Joseph Myers <joseph@codesourcery.com>
Date: Thu, 31 Jan 2013 22:55:29 +0000
Subject: Fix casinh spurious underflows away from [-i,i] (bug 15062).

---
 math/k_casinhl.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'math/k_casinhl.c')

diff --git a/math/k_casinhl.c b/math/k_casinhl.c
index 6412979..110ae33 100644
--- a/math/k_casinhl.c
+++ b/math/k_casinhl.c
@@ -64,6 +64,26 @@ __kernel_casinhl (__complex__ long double x, int adj)
       res = __clogl (y);
       __real__ res += M_LN2l;
     }
+  else if (rx >= 0.5L && ix < LDBL_EPSILON / 8.0L)
+    {
+      long double s = __ieee754_hypotl (1.0L, rx);
+
+      __real__ res = __ieee754_logl (rx + s);
+      if (adj)
+	__imag__ res = __ieee754_atan2l (s, __imag__ x);
+      else
+	__imag__ res = __ieee754_atan2l (ix, s);
+    }
+  else if (rx < LDBL_EPSILON / 8.0L && ix >= 1.5L)
+    {
+      long double s = __ieee754_sqrtl ((ix + 1.0L) * (ix - 1.0L));
+
+      __real__ res = __ieee754_logl (ix + s);
+      if (adj)
+	__imag__ res = __ieee754_atan2l (rx, __copysignl (s, __imag__ x));
+      else
+	__imag__ res = __ieee754_atan2l (s, rx);
+    }
   else
     {
       __real__ y = (rx - ix) * (rx + ix) + 1.0;
-- 
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