Re: [PATCH] fix BUILD_BUG_ON() and a couple of bogus uses of it

David Miller
2009-09-18T00:45:15Z

From: David Miller <davem@davemloft.net>
Date: Thu, 17 Sep 2009 17:31:54 -0700 (PDT)

> From: Andrew Morton <akpm@linux-foundation.org>
> Date: Thu, 17 Sep 2009 17:15:04 -0700
>
>> There's a shortcoming in the current BUILD_BUG_ON() - it silently does
>> nothing if passed a non-constant arg.
>>
>> I suspect that in the 2.6.31 code, that BUILD_BUG_ON() just does
>> nothing at all, and that Jan's patch is now exposing this. It might be
>> compiler-version dependent too.
>>
>>
>> <tests it>
>>
>> Yup, on base 2.6.31, this:
>
> Ok, I'll have to either change this function to a macro or
> get rid of the check.

I can't even get GCC to see the constant evaluated by is_power_of_2().

I give up, I'll just remove the BUILD_BUG_ON() entirely.