[src/gmp_op.c] Fixed a bug in mpfr_cmp_q on NaN rational: the NaN flag

  was set by mpfr_set_q, but the flags were not restored just after.
[tests/tgmpop.c] For mpfr_cmp_q, improved the test where x is NaN by
  checking all the flags (not just erange) and added a test where y is
  a NaN rational.
(merged changesets r12343,12677 from the trunk)

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/branches/4.0@12679 280ebfd0-de03-0410-8827-d642c229c3f4

2 files changed, 32 insertions, 5 deletions

diff --git a/src/gmp_op.c b/src/gmp_op.c
index eab65479c..dc00527f5 100644
--- a/src/gmp_op.c
+++ b/src/gmp_op.c
@@ -455,8 +455,12 @@ mpfr_cmp_q (mpfr_srcptr x, mpq_srcptr q)
   if (MPFR_UNLIKELY (mpz_sgn (mpq_denref (q)) == 0))
     {
       /* q is an infinity or NaN */
-      mpfr_init2 (t, 2);
+      mpfr_flags_t old_flags;
+
+      mpfr_init2 (t, MPFR_PREC_MIN);
+      old_flags = __gmpfr_flags;
       mpfr_set_q (t, q, MPFR_RNDN);
+      __gmpfr_flags = old_flags;
       res = mpfr_cmp (x, t);
       mpfr_clear (t);
       return res;
diff --git a/tests/tgmpop.c b/tests/tgmpop.c
index 27a169026..f1a36fbd2 100644
--- a/tests/tgmpop.c
+++ b/tests/tgmpop.c
@@ -307,16 +307,39 @@ test_cmp_q (mpfr_prec_t pmin, mpfr_prec_t pmax, int nmax)
   mpfr_init2 (z, MPFR_PREC_MIN);
   mpq_init (y);
 
-  /* check the erange flag when x is NaN */
+  /* Check the flags when x is NaN: the erange flags must be set, and
+     only this one. */
   mpfr_set_nan (x);
   mpq_set_ui (y, 17, 1);
-  mpfr_clear_erangeflag ();
+  mpfr_clear_flags ();
   res1 = mpfr_cmp_q (x, y);
-  if (res1 != 0 || mpfr_erangeflag_p () == 0)
+  if (res1 != 0 || __gmpfr_flags != MPFR_FLAGS_ERANGE)
     {
       printf ("Error for mpfr_cmp_q (NaN, 17)\n");
       printf ("Return value: expected 0, got %d\n", res1);
-      printf ("Erange flag: expected set, got %d\n", mpfr_erangeflag_p ());
+      printf ("Expected flags:");
+      flags_out (MPFR_FLAGS_ERANGE);
+      printf ("Got flags:     ");
+      flags_out (__gmpfr_flags);
+      exit (1);
+    }
+
+  /* Check the flags when y is NaN: the erange flags must be set, and
+     only this one. */
+  mpfr_set_ui (x, 42, MPFR_RNDN);
+  /* A NaN rational is represented by 0/0 (MPFR extension). */
+  mpz_set_ui (mpq_numref (y), 0);
+  mpz_set_ui (mpq_denref (y), 0);
+  mpfr_clear_flags ();
+  res1 = mpfr_cmp_q (x, y);
+  if (res1 != 0 || __gmpfr_flags != MPFR_FLAGS_ERANGE)
+    {
+      printf ("Error for mpfr_cmp_q (42, NaN)\n");
+      printf ("Return value: expected 0, got %d\n", res1);
+      printf ("Expected flags:");
+      flags_out (MPFR_FLAGS_ERANGE);
+      printf ("Got flags:     ");
+      flags_out (__gmpfr_flags);
       exit (1);
     }