Messages in this thread Patch in this message | | | Date | Tue, 24 Jan 2023 22:48:16 +0100 | From | Michael Karcher <> | Subject | [PATCH v5 1/1] arch/sh: avoid spurious sizeof-pointer-div warning |
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Gcc warns about the pattern sizeof(void*)/sizeof(void), as it looks like the abuse of a pattern to calculate the array size. This pattern appears in the unevaluated part of the ternary operator in _INTC_ARRAY if the parameter is NULL.
The replacement uses an alternate approach to return 0 in case of NULL which does not generate the pattern sizeof(void*)/sizeof(void), but still emits the warning if _INTC_ARRAY is called with a nonarray parameter.
This patch is required for successful compilation with -Werror enabled.
The idea to use _Generic for type distinction is taken from Comment #7 inhttps://gcc.gnu.org/bugzilla/show_bug.cgi?id=108483 by Jakub Jelinek
Signed-off-by: Michael Karcher<kernel@mkarcher.dialup.fu-berlin.de> --- (resend of the mail as plaintext only instead of multipart/alternative) History: v5: - Cleanly generated the patch v4: - Put the case distinction into the numerator instead of the denominator - Refactor the case disctinction into a second macro v3: - I had a stern discussion with Thunderbird about not mangling the space characters in my email, and I hope spaces get sent as standard spaces now v2: - improve title and remove mostly redundant first sentence of the description - adjust formatting of the _Generic construction
diff --git a/include/linux/sh_intc.h b/include/linux/sh_intc.h index c255273b0281..37ad81058d6a 100644 --- a/include/linux/sh_intc.h +++ b/include/linux/sh_intc.h @@ -97,7 +97,10 @@ struct intc_hw_desc { unsigned int nr_subgroups; };
-#define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a) +#define _INTC_SIZEOF_OR_ZERO(a) (_Generic(a, \ + typeof(NULL): 0, \ + default: sizeof(a))) +#define _INTC_ARRAY(a) a, _INTC_SIZEOF_OR_ZERO(a)/sizeof(*a)
#define INTC_HW_DESC(vectors, groups, mask_regs, \ prio_regs, sense_regs, ack_regs) \
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