[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PULL 07/21] atomic.h: Work around gcc spurious "unused val
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PULL 07/21] atomic.h: Work around gcc spurious "unused value" warning |
Date: |
Thu, 10 May 2018 18:45:05 +0100 |
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 <address@hidden>
Reviewed-by: Richard Henderson <address@hidden>
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
---
include/qemu/atomic.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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; \
})
--
2.17.0
- [Qemu-devel] [PULL 00/21] target-arm queue, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 03/21] pc: simplify MachineClass::get_hotplug_handler handling, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 02/21] softfloat: Handle default NaN mode after pickNaNMulAdd, not before, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 01/21] hw/arm/iotkit.c: fix minor memory leak, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 07/21] atomic.h: Work around gcc spurious "unused value" warning,
Peter Maydell <=
- [Qemu-devel] [PULL 08/21] tcg: Introduce helpers for integer min/max, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 06/21] make sure that we aren't overwriting mc->get_hotplug_handler by accident, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 09/21] target/arm: Use new min/max expanders, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 10/21] target/xtensa: Use new min/max expanders, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 05/21] arm/boot: split load_dtb() from arm_load_kernel(), Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 12/21] tcg: Use GEN_ATOMIC_HELPER_FN for opposite endian atomic add, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 11/21] tcg: Introduce atomic helpers for integer min/max, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 04/21] platform-bus-device: use device plug callback instead of machine_done notifier, Peter Maydell, 2018/05/10