Re: [PATCH] tools/perf: Do not set a variable unless it will be used

From: Ricardo Ribalda
Date: Fri Jun 04 2021 - 15:25:51 EST


Hi Peter

On Fri, 4 Jun 2021 at 11:36, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Fri, Jun 04, 2021 at 11:26:38AM +0200, Ricardo Ribalda wrote:
> > clang-13 triggers the following warning:
> >
> > bench/inject-buildid.c:351:6: error: variable 'len' set but not used [-Werror,-Wunused-but-set-variable]
> > u64 len = 0;
> >
> > This patch sets the value to len only if it will be used afterwards.
>
> My vote would be to kill that warning, what absolute shite.

My knowledge of llvm codebase is close to NULL, so it is much easier
for me to "fix" the code.

I would assume that the static analyser has found a magic condition
where the previous if always returns false, and has managed to
"optimize" the code.





--
Ricardo Ribalda