diff -Naur mpfr-2.1.1-p2/atanh.c mpfr-2.1.1-p3/atanh.c
--- mpfr-2.1.1-p2/atanh.c	2004-02-13 09:33:55.000000000 +0000
+++ mpfr-2.1.1-p3/atanh.c	2005-03-17 00:24:50.801314000 +0000
@@ -1,6 +1,6 @@
 /* mpfr_atanh -- Inverse Hyperbolic Tangente of Unsigned Integer Number
 
-Copyright 2001, 2002, 2003, 2004 Free Software Foundation.
+Copyright 2001, 2002, 2003, 2004, 2005 Free Software Foundation.
 
 This file is part of the MPFR Library.
 
@@ -58,14 +58,11 @@
   /* atanh(x) = NaN as soon as |x| > 1, and arctanh(+/-1) = +/-Inf */
   if (MPFR_EXP(xt) > 0)
     {
-      if (MPFR_EXP(xt) == 1)
+      if (MPFR_EXP(xt) == 1 && mpfr_powerof2_raw (xt))
         {
-          if (mpfr_cmp_ui (xt, 1) || mpfr_cmp_si (xt, -1))
-            {
-              MPFR_SET_INF(y);
-              MPFR_SET_SAME_SIGN(y, xt);
-              MPFR_RET(0);
-            }
+          MPFR_SET_INF(y);
+          MPFR_SET_SAME_SIGN(y, xt);
+          MPFR_RET(0);
         }
       MPFR_SET_NAN(y);
       MPFR_RET_NAN;
diff -Naur mpfr-2.1.1-p2/tests/tatanh.c mpfr-2.1.1-p3/tests/tatanh.c
--- mpfr-2.1.1-p2/tests/tatanh.c	2004-02-13 09:33:55.000000000 +0000
+++ mpfr-2.1.1-p3/tests/tatanh.c	2005-03-17 00:21:40.347287000 +0000
@@ -1,6 +1,6 @@
 /* Test file for mpfr_atanh.
 
-Copyright 2001, 2002, 2003, 2004 Free Software Foundation.
+Copyright 2001, 2002, 2003, 2004, 2005 Free Software Foundation.
 Adapted from tatan.c.
 
 This file is part of the MPFR Library.
@@ -32,6 +32,7 @@
 special (void)
 {
   mpfr_t x, y, z;
+  int i;
 
   mpfr_init (x);
   mpfr_init (y);
@@ -53,20 +54,24 @@
       exit (1);
     }
 
-  /* atanh(+/-2) = NaN */
-  mpfr_set_ui (x, 2, GMP_RNDN);
-  mpfr_atanh (y, x, GMP_RNDN);
-  if (!mpfr_nan_p (y))
+  /* atanh(+/-x) = NaN if x > 1 */
+  for (i = 3; i <= 6; i++)
     {
-      printf ("Error: mpfr_atanh(2) <> NaN\n");
-      exit (1);
-    }
-  mpfr_neg (x, x, GMP_RNDN);
-  mpfr_atanh (y, x, GMP_RNDN);
-  if (!mpfr_nan_p (y))
-    {
-      printf ("Error: mpfr_atanh(-2) <> NaN\n");
-      exit (1);
+      mpfr_set_si (x, i, GMP_RNDN);
+      mpfr_div_2ui (x, x, 1, GMP_RNDN);
+      mpfr_atanh (y, x, GMP_RNDN);
+      if (!mpfr_nan_p (y))
+        {
+          printf ("Error: mpfr_atanh(%d/2) <> NaN\n", i);
+          exit (1);
+        }
+      mpfr_neg (x, x, GMP_RNDN);
+      mpfr_atanh (y, x, GMP_RNDN);
+      if (!mpfr_nan_p (y))
+        {
+          printf ("Error: mpfr_atanh(-%d/2) <> NaN\n", i);
+          exit (1);
+        }
     }
 
   /* atanh(+0) = +0, atanh(-0) = -0 */