tests/tfrac.c: added testcase for bug in mpfr_frac.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@6453 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 24 insertions, 0 deletions

diff --git a/tests/tfrac.c b/tests/tfrac.c
index 5c8151c0d..a09807813 100644
--- a/tests/tfrac.c
+++ b/tests/tfrac.c
@@ -172,6 +172,28 @@ special (void)
   mpfr_clear (t);
 }
 
+static void
+bug20090918 (void)
+{
+  mpfr_t x, y;
+  mp_limb_t y0;
+
+  mpfr_init2 (x, 53);
+  mpfr_init2 (y, 13);
+  mpfr_set_str (x, "61680.352935791015625", 10, MPFR_RNDN);
+  mpfr_frac (y, x, MPFR_RNDZ);
+  y0 = MPFR_MANT(y)[0];
+  while ((y0 >> 1) << 1 == y0)
+    y0 >>= 1;
+  if (y0 > 0x2000)
+    {
+      printf ("Error in bug20090918 (significand has more than 13 bits).\n");
+      exit (1);
+    }
+  mpfr_clear (x);
+  mpfr_clear (y);
+}
+
 #define TEST_FUNCTION mpfr_frac
 #include "tgeneric.c"
 
@@ -227,6 +249,8 @@ main (void)
   mpfr_clear (ip);
   mpfr_clear (fp);
 
+  bug20090918 ();
+
   test_generic (2, 1000, 10);
 
   tests_end_mpfr ();