[tests/tlngamma.c] added failing test with mpfr-4.0.0-rc2

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@12028 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/tlngamma.c b/tests/tlngamma.c
index 377097807..88fd8b358 100644
--- a/tests/tlngamma.c
+++ b/tests/tlngamma.c
@@ -252,11 +252,45 @@ special (void)
   mpfr_clear (y);
 }
 
+/* test failing with GMP_CHECK_RANDOMIZE=1513869588 */
+static void
+bug20171220 (void)
+{
+  mpfr_t x, y, z;
+  int inex;
+  
+  mpfr_init2 (x, 15);
+  mpfr_init2 (y, 15);
+  mpfr_init2 (z, 15);
+
+  mpfr_set_str (x, "1.01111e+00", 10, MPFR_RNDN); /* x = 8283/8192 */
+  inex = mpfr_lngamma (y, x, MPFR_RNDN);
+  mpfr_set_str (z, "-0.0063109971733698154140545190234", 10, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_equal_p (y, z));
+  MPFR_ASSERTN(inex > 0);
+
+  mpfr_set_prec (x, 43);
+  mpfr_set_prec (y, 1);
+  mpfr_set_prec (z, 1);
+  mpfr_set_str (x, "9.8888652212918e-01", 10, MPFR_RNDN);
+  /* lngamma(x) = 0.00651701007222520, should be rounded up to 0.0078125 */
+  inex = mpfr_lngamma (y, x, MPFR_RNDU);
+  mpfr_set_ui_2exp (z, 1, -7, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_equal_p (y, z));
+  MPFR_ASSERTN(inex > 0);
+
+  mpfr_clear (x);
+  mpfr_clear (y);
+  mpfr_clear (z);
+}
+
 int
 main (void)
 {
   tests_start_mpfr ();
 
+  bug20171220 ();
+
   special ();
   test_generic (MPFR_PREC_MIN, 100, 2);