Re: [Patch, Fortran] PR 85599: warn about short-circuiting of logical expressions for non-pure functions

[Janus Weil <janus at gcc dot gnu dot org>]

2018-07-17 17:18 GMT+02:00 Fritz Reese <fritzoreese@gmail.com>:
>> 2018-07-17 9:52 GMT+02:00 Janus Weil <janus@gcc.gnu.org>:
>> > In other words: Does it make sense to tone down
>> > -Wfunction-elimination, by only warning about impure functions?
>>
>> Here is an update of the patch which does that. Regtesting now ...
>
> Would not this break the testcase function_optimize_5.f90 :

My regtest says so as well ;)


> The docs for -Wfunction-elimination would read:
>
>> Warn if any calls to functions are eliminated by the optimizations
>> enabled by the @option{-ffrontend-optimize} option.
>> This option is implied by @option{-Wextra}.
>
> However, with your patch, it should probably read something like "warn
> if any calls to impure functions are eliminated..." Possibly with an
> explicit remark indicating that pure functions are not warned.

Yes.

However, the test case above seems to indicate that the
function-elimination optimization is not applied to impure functions
anyway (which is good IMHO). It that is true, then my modifications
practically disable the old -Wfunction-elimination warnings completely
:/



> Have you considered using levels for the flag, such that the original
> behavior of -Wfunction-elimination would be retained with e.g.
> -Wfunction-elimination=2 whereas one could use
> -Wfunction-elimination=1 (or similar) to omit warnings about impure
> functions?

One could do that, but IMHO it would be overkill. I don't see much
sense in warning for the elimination of pure functions. But maybe I'm
missing something?

Cheers,
Janus