diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2018-05-10 18:10:57 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2018-05-10 18:10:57 +0100 |
| commit | cd95fc28fb6d8afced0d70ce52c294d0761a9daa (patch) | |
| tree | e40abcab80b13b762aac605ee27bc93128e48ed7 | |
| parent | debbdc00182eb83db5d8acc241feb37c81bc63ec (diff) | |
atomic.h: Work around gcc spurious "unused value" warning
Some versions of gcc produce a spurious warning if the result of
__atomic_compare_echange_n() is not used and the type involved
is a signed 8 bit value:
error: value computed is not used [-Werror=unused-value]
This has been seen on at least
gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
Work around this by using an explicit cast to void to indicate
that we don't care about the return value.
We don't currently use our atomic_cmpxchg() macro on any signed
8 bit types, but the upcoming support for the Arm v8.1-Atomics
will require it.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
| -rw-r--r-- | include/qemu/atomic.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h index d73c9e14d7..9ed39effd3 100644 --- a/include/qemu/atomic.h +++ b/include/qemu/atomic.h @@ -187,7 +187,7 @@ /* Returns the eventual value, failed or not */ #define atomic_cmpxchg__nocheck(ptr, old, new) ({ \ typeof_strip_qual(*ptr) _old = (old); \ - __atomic_compare_exchange_n(ptr, &_old, new, false, \ + (void)__atomic_compare_exchange_n(ptr, &_old, new, false, \ __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); \ _old; \ }) |