Use volatile global counters in test-tgmath.c.

If build with -Os on s390x, the test-tgmath fails with:
float functions not called often enough (-10000)

Within compile_testf(), the counter (count_float) is saved
before the complex functions are called.
Afterwards the saved counter differs to the current-counter.

But the tests with the complex functions do not increment count_float!
Instead count_float is saved to a register before calling totalorder
and totalordermag which both increment count_float.
The compiler is allowed to do that as totalorderf and totalordermagf
is declared with __attribute__ ((__const__)) in math/bits/mathcalls.h.

Thus this patch adjusts the global counters to be volatile.
Then count_float is saved after totalordermag.

ChangeLog:

	* math/test-tgmath.c (count_double, count_float,
	count_ldouble, count_cdouble, count_cfloat,
	count_cldouble): Use volatile int.

1 files changed, 6 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index ec19da47f2..df941db962 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2018-04-19  Stefan Liebler  <stli@linux.vnet.ibm.com>
+
+	* math/test-tgmath.c (count_double, count_float,
+	count_ldouble, count_cdouble, count_cfloat,
+	count_cldouble): Use volatile int.
+
 2018-04-19  Samuel Thibault  <samuel.thibault@ens-lyon.org>
 
 	* sysdeps/mach/hurd/i386/Makefile [$(subdir) = conform]