Re: [wireless-next:master 70/102] drivers/net/wireless/b43/phy_ht.c:338:35: sparse: cast truncates bits from constant value (ffff3fff becomes 3fff)

[Dan Carpenter <dan.carpenter@oracle.com>]

On Tue, Sep 16, 2014 at 10:17:18AM +0800, Fengguang Wu wrote:
> I could disable this warning in my reports, but CC sparse authors
> first to check if there are more elegant solutions.

int main(void)
{
        printf("%x\n", (unsigned short)~(0xc00));   // <-- ok
        printf("%x\n", (unsigned short)~(0xc000));  // <-- complains

        return 0;
}

test.c:10:40: warning: cast truncates bits from constant value (ffff3fff becomes 3fff)

The reason the first one is ok is because we don't complain if the
truncated bits are purely sign bits.  I feel like it should apply to the
second statement as well.  If we're only masking out 0xffff then don't
complain.

regards,
dan carpenter