[PATCH][testsuite] Avoid division by zero.

[Ilya Tocar]

> >> We won't get zero from exponential function, so expecting zero result
> >> is flawed anyway.
> >>
> >> If we would like to introduce universal epsilon comparisons into the
> >> testsuite, then please read [1]. Being overly pedantic, the definition
> >> should be "|(v[i] - u.a[i]) / v[i]|", as stated in [2].
> >>
> >> [1] http://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
> >> [2] http://en.wikipedia.org/wiki/Relative_error
> >>
> >
> > We get zero from testing zero-masking. Currently we produce 0/0 = NaN.
> > Comparison with NaN is always false, so tests pass. But I think that
> > this should be fixed to avoid division by zero. As for being more
> > pedantic about comparison, I doubt that its useful, when we use
> > 0.0001 as eps.
> 
> In this case, please add simple check for zero, with the above
> comment. We don't test exp function, but masking.
>

Something like this?

---
 gcc/testsuite/gcc.target/i386/m512-check.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/gcc/testsuite/gcc.target/i386/m512-check.h b/gcc/testsuite/gcc.target/i386/m512-check.h
index 3209039..a96a103 100644
--- a/gcc/testsuite/gcc.target/i386/m512-check.h
+++ b/gcc/testsuite/gcc.target/i386/m512-check.h
@@ -58,6 +58,16 @@ check_rough_##UINON_TYPE (UINON_TYPE u, const VALUE_TYPE *v,	\
 								\
   for (i = 0; i < ARRAY_SIZE (u.a); i++)			\
     {								\
+      /* We will always have v[i] == 0 == u.a[i]  for some i,	\
+         when we test zero-masking.  */				\
+      if (v[i] == 0.0 && u.a[i] == 0.0)				\
+	continue;						\
+      if (v[i] == 0.0 && u.a[i] != 0.0)				\
+	{							\
+	  err++;						\
+	  PRINTF ("%i: " FMT " != " FMT "\n",			\
+		  i, v[i], u.a[i]);				\
+	}							\
       VALUE_TYPE rel_err = (u.a[i] - v[i]) / v[i];		\
       if (((rel_err < 0) ? -rel_err : rel_err) > eps)		\
 	{							\
-- 
1.8.3.1