1 files changed, 21 insertions, 0 deletions
diff --git a/tests/troot.c b/tests/troot.c
index c6649cf8c..e173db59a 100644
--- a/tests/troot.c
+++ b/tests/troot.c
@@ -405,6 +405,26 @@ cmp_pow (void)
   mpfr_clears (x, y1, y2, (mpfr_ptr) 0);
 }
 
+static void
+bug20171214 (void)
+{
+  mpfr_t x, y;
+  int inex;
+
+  mpfr_init2 (x, 805);
+  mpfr_init2 (y, 837);
+  mpfr_set_ui (x, 1, MPFR_RNDN);
+  inex = mpfr_root (y, x, 120, MPFR_RNDN);
+  MPFR_ASSERTN (inex == 0);
+  MPFR_ASSERTN (mpfr_cmp_ui (y, 1) == 0);
+  mpfr_set_si (x, -1, MPFR_RNDN);
+  inex = mpfr_root (y, x, 121, MPFR_RNDN);
+  MPFR_ASSERTN (inex == 0);
+  MPFR_ASSERTN (mpfr_cmp_si (y, -1) == 0);
+  mpfr_clear (x);
+  mpfr_clear (y);
+}
+
 int
 main (void)
 {
@@ -415,6 +435,7 @@ main (void)
 
   tests_start_mpfr ();
 
+  bug20171214 ();
   exact_powers (3, 1000);
   special ();
   bigint ();