Fixed an exponent/flags-related bug in lngamma.c.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/branches/2.2@4137 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 9 insertions, 4 deletions

diff --git a/lngamma.c b/lngamma.c
index 343f8a5ee..3ef3a1fe2 100644
--- a/lngamma.c
+++ b/lngamma.c
@@ -154,11 +154,16 @@ GAMMA_FUNC (mpfr_ptr y, mpfr_srcptr z0, mp_rnd_t rnd)
     }
 
   /* if x < 0 and -2k-1 <= x <= -2k, then lngamma(x) = NaN */
-  if (MPFR_IS_NEG(z0) && ((mpfr_get_si (z0, GMP_RNDZ) % 2) == 0
-                          || mpfr_integer_p (z0)))
+  if (MPFR_IS_NEG (z0))
     {
-      MPFR_SET_NAN (y);
-      MPFR_RET_NAN;
+      MPFR_SAVE_EXPO_MARK (expo);
+      if (mpfr_get_si (z0, GMP_RNDZ) % 2 == 0 || mpfr_integer_p (z0))
+        {
+          MPFR_SAVE_EXPO_FREE (expo);
+          MPFR_SET_NAN (y);
+          MPFR_RET_NAN;
+        }
+      MPFR_SAVE_EXPO_FREE (expo);
     }
 #endif