state of clang(1)'s -Wshift-count-negative and -Wshift-overflow
warnings
Dimitry Andric
dim at FreeBSD.org
Thu Nov 3 15:11:06 UTC 2011
On 2011-11-03 11:45, Alexander Best wrote:
...
> /usr/git-freebsd-head/sys/dev/ath/ath_hal/ar5210/ar5210_power.c:36:3: warning: signed shift result (0x200000000) requires 35 bits to represent, but 'int' only has 32 bits [-Wshift-overflow]
> OS_REG_RMW_FIELD(ah, AR_SCR, AR_SCR_SLE, AR_SCR_SLE_ALLOW);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> /usr/git-freebsd-head/sys/dev/ath/ath_hal/ah_internal.h:471:42: note: expanded from macro 'OS_REG_RMW_FIELD'
> (OS_REG_READ(_a, _r) &~ (_f)) | (((_v) << _f##_S) & (_f)))
> ^
> /usr/git-freebsd-head/sys/dev/ath/ah_osdep.h:127:49: note: expanded from macro 'OS_REG_WRITE'
> (bus_space_handle_t)(_ah)->ah_sh, (_reg), (_val))
>
> iirc, back then, it was labeled as a clang bug. however testing with clang tot,
> i still get those warnings. so i just wanted to ask again, whether the warnings
> are really bogus, or if these warnings actually indicate issues during
> shifting?
Those warnings are bogus, and due to this bug:
http://llvm.org/bugs/show_bug.cgi?id=10030
Unfortunately, it is still not fixed for the 3.0 release branch, and I
don't expect it will be fixed for the actual release.
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