nathanchance added a comment.
I am still running a series of builds against the Linux kernel but I already
see one instance of this warning where the suggestion would change the meaning
of the code in an incorrect way:
drivers/input/touchscreen.c:81:17: warning: use of bitwise '|' with boolean
operands [-Wbool-operation]
data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/input/touchscreen.c:81:17: warning: use of bitwise '|' with boolean
operands [-Wbool-operation]
data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/input/touchscreen.c:94:17: warning: use of bitwise '|' with boolean
operands [-Wbool-operation]
data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/input/touchscreen.c:94:17: warning: use of bitwise '|' with boolean
operands [-Wbool-operation]
data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/input/touchscreen.c:108:17: warning: use of bitwise '|' with boolean
operands [-Wbool-operation]
data_present = touchscreen_get_prop_u32(dev,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
5 warnings generated.
Which corresponds to this file:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/input/touchscreen.c?h=v5.14-rc6
If the calls to `touchscreen_get_prop_u32` short circuit, we could use
`maximum` or `fuzz` uninitialized. There might be a cleaner way to rewrite that
block to avoid the warning but based on the other instances of this warning I
see, I am not sure `|` vs. `||` is worth warning about (but I am happy to hear
examples of how it could be a bug). Most people realize `&&` short circuits (as
`if (a && foo(a->...))` is relatively common) but most probably are not
thinking about `||` short circuiting (and it would be more of an optimization
than correctness issue as far as I understand it).
Additionally, I have not caught any instances of `&` being used instead of
`&&`, including the ones I notated previously; those were caught because only
the right side had side effects. As was pointed out here and on the mailing
list
<https://lore.kernel.org/r/defb9e5133234835950c21511d776...@acums.aculab.com/>,
the `lib/zstd/` warning is probably a bug, as the short circuit should happen
if `offset_1` is zero, otherwise there is unnecessary work done.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D108003/new/
https://reviews.llvm.org/D108003
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