[Bug c++/78964] gcc fails to detect pointless increment

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78964

--- Comment #7 from David Binderman <dcb314 at hotmail dot com> ---
(In reply to Markus Trippelsdorf from comment #4)
> And the Linux kernel would not see these warnings anyway:
> 
> Makefile:
>  707 # These warnings generated too much noise in a regular build.
>  708 # Use make W=1 to enable them (see scripts/Makefile.build)
>  709 KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
>  710 KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)

Linux kernel just an example. There are over 100 similar bugs in llvm. 
about 20 in netBSD kernel, about a dozen in gcc itself etc.

Unless you are claiming that every source code that uses gcc switches
off -Wunused-but-set-variable, then I can see some value in this new warning.

From a user perspective, this new warning isn't a lot different to
-Wunused-but-set-variable and that got implemented, why not this ?