[PATCH, libstdc++]: Avoid "libsupc++/guard.cc:118:18: warning: variable ‘__p’ set but not used" warning

[Uros Bizjak]

Hello!

2015-07-01  Uros Bizjak  <ubiz...@gmail.com>

    * libsupc++/guard.cc (__test_and_acquire): Use __p after __atomic_load
    to avoid unused variable warning.
    (__set_and_release): Use __p after __atomic_store to avoid unused
    variable warning.

Bootstrapped and regression tested on x86_64-linux-gnu.

OK for mainline?

Uros.

Index: libsupc++/guard.cc
===================================================================
--- libsupc++/guard.cc  (revision 225221)
+++ libsupc++/guard.cc  (working copy)
@@ -117,6 +117,7 @@ __test_and_acquire (__cxxabiv1::__guard *g)
   unsigned char __c;
   unsigned char *__p = reinterpret_cast<unsigned char *>(g);
   __atomic_load (__p, &__c,  __ATOMIC_ACQUIRE);
+  (void) __p;
   return _GLIBCXX_GUARD_TEST(&__c);
 }
 #  define _GLIBCXX_GUARD_TEST_AND_ACQUIRE(G) __test_and_acquire (G)
@@ -132,6 +133,7 @@ __set_and_release (__cxxabiv1::__guard *g)
   unsigned char *__p = reinterpret_cast<unsigned char *>(g);
   unsigned char val = 1;
   __atomic_store (__p, &val, __ATOMIC_RELEASE);
+  (void) __p;
 }
 #  define _GLIBCXX_GUARD_SET_AND_RELEASE(G) __set_and_release (G)
 # endif