Re: [PATCH] include: Fix compile warning in include/linux/bitops.h

From: Andrew Morton
Date: Mon Jun 11 2012 - 18:59:26 EST


On Fri, 8 Jun 2012 23:15:30 -0400
Namjae Jeon <linkinjeon@xxxxxxxxx> wrote:

> The compile warning is caused by __const_hweight8 when using
> hweight_long with -Wsign-compare option.
> The reason is that the default return value of this macro is signed.
> So need type casting to remove warning.

um, what warning?

Please always quote the compiler messages when fixing build warnings or
errors.

> index fa2a50b..3ad0dae 100644
> --- a/include/asm-generic/bitops/const_hweight.h
> +++ b/include/asm-generic/bitops/const_hweight.h
> @@ -4,7 +4,7 @@
> /*
> * Compile time versions of __arch_hweightN()
> */
> -#define __const_hweight8(w) \
> +#define __const_hweight8(w) (unsigned long) \
> ( (!!((w) & (1ULL << 0))) + \
> (!!((w) & (1ULL << 1))) + \
> (!!((w) & (1ULL << 2))) + \

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