On Mon, Mar 7, 2016 at 2:34 PM, Marek Polacek <pola...@redhat.com> wrote:
> On Fri, Mar 04, 2016 at 07:17:46PM +0100, Uros Bizjak wrote:
>> Hello!
>>
>> > This is not a regression but I thought I'd post this anyway. Martin
>> > reported
>> > that we generate -Wunused-value warnings on the attached testcase, which
>> > arguable doesn't make sense. Setting TREE_USED suppresses the warning.
>> > Since
>> > we already compute 'fetch_op' I used that. (This warning doesn't trigger
>> > e.g.
>> > for __atomic_load/store/compare.)
>> >
>> > Bootstrapped/regtested on x86_64-linux, ok for trunk or gcc7?
>> >
>> > 2016-03-04 Marek Polacek <pola...@redhat.com>
>> >
>> > PR c/69407
>> > * c-common.c (resolve_overloaded_builtin): Set TREE_USED for the fetch
>> > operations.
>> >
>> > * gcc.dg/atomic-op-6.c: New test.
>>
>> You can probably revert my workaround [1] that suppressed these
>> warnings in libsupc++/guard.cc.
>
> Ah, thanks for the heads-up, I'll do that once I get the patch in.
I have committed the attached revert after bootstrap on
x86_64-linux-gnu {,-m32}. There were no warnings when compiling
guard.cc.
2016-03-18 Uros Bizjak <ubiz...@gmail.com>
Revert:
2015-07-02 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.
Uros.
Index: libsupc++/guard.cc
===================================================================
--- libsupc++/guard.cc (revision 234330)
+++ libsupc++/guard.cc (working copy)
@@ -117,7 +117,6 @@ __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)
@@ -133,7 +132,6 @@ __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
