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SubjectRe: [PATCH for 3.12] mutex: Avoid gcc version dependent __builtin_constant_p() usage.
op 17-10-13 12:52, Peter Zijlstra schreef:
> On Thu, Oct 17, 2013 at 07:45:29PM +0900, Tetsuo Handa wrote:
>> Commit 040a0a37 "mutex: Add support for wound/wait style locks" used
>> "!__builtin_constant_p(p == NULL)" but gcc 3.x cannot handle such expression
>> correctly, leading to boot failure when built with CONFIG_DEBUG_MUTEXES=y.
> So I completely forgot all about this, but wouldn't something like:
>
> !(__builtin_constant_p(p) && p == NULL)
>
> Not also work and generate the same code?
>
See earlier discussion. It was already answered why that was undesirable. ;)

~Maarten


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