Re: [PATCH] compiler.h: don't use temporary variable in __compiletime_assert()

From: Peter Zijlstra
Date: Thu May 08 2014 - 02:56:56 EST


On Thu, May 08, 2014 at 08:31:25AM +0200, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg@xxxxxxxxx>
>
> Usually, BUG_ON and friends aren't even evaluated in sparse, but
> recently compiletime_assert_atomic_type() was added, and that now
> results in a sparse warning every time it is used.
>
> The reason turns out to be the temporary variable, after it sparse
> no longer considers the value to be a constant, and results in a
> warning and an error. The error is the more annoying part of this
> as it suppresses any further warnings in the same file, hiding
> other problems.
>
> Since this is all about compile time and the condition should be
> side-effect free to start with, there's no downside (apart maybe
> from a slight compilation time penalty?) to just duplicating it,
> leaving sparse able to evaluate it at check time, getting rid of
> the warning and error.
>
> Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>

Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
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