Re: [PATCH 3/3] lib/regexec: Resolve unused variable

[Paul Eggert]

On 8/23/21 3:38 AM, Darren Kenny wrote:

> What I did here was to not overwrite the value if DEBUG is set,
> since it appeared to never be checked anyway within the for-loop.

Yes, but although your patch pacified Coverity I still don't understand 
exactly why. I'd like to get to the bottom of it before continuing.

> I can only assume (pun not intended) that this
> is ending up as a no-op for our build, which means that Coverity sees it
> as never being read after the for-loop.
I'm working blind here, since Coverity's documentation is secret, which 
means you'll need to help out by reading its documentation and/or 
running Coverity yourself. Can you do that and let us know the following?

* What values does Coverity define the macros __GNUC__ and 
__GNUC_MINOR__ to? Or does it leave these symbols undefined?

* Similarly for _MSC_VER (defined by Microsoft C compilers).

* Does Coverity support the __builtin_unreachable and/or __builtin_trap 
functions, like GCC does? (See their use in verify.h.)

* Does Coverity support __assume, like Microsoft C does? (Also see 
verify.h.)

* Does Coverity support __has_builtin, like GCC and Clang do? (Again, 
see verify.h.)

* Are you compiling with -DGCC_LINT and/or -Dlint?

* Does the attached patch work for you? If not, why not, and what sort 
of improvements could be made?

Thanks.

coverity2.diff
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