Re: [PATCH] kbuild: add some extra warning flags unconditionally

[Nick Desaulniers]

From: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> On Thu, May 9, 2019 at 4:11 PM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote:
> > BTW, is this a speedup when doing CC/LD FLAGS etc checks unconditionally?
>
> Yes.
> cc-option is somewhat costly because it invoked the compiler to
> check if the given flag is supported.
>
> So, I want to get rid of as many cc-option calls as possible.
>
>
> > Asking in general - do you have any numbers :-)?
>
> Removing a couple of cc-options does not make
> a measurable difference in general use-cases.
>
> But, this might be more beneficial for chrome OS
> because $(CC) is a wrapper and invoking it is much more expensive.

Android does too, which we plan on removing as we recently measured
the performance cost of 5% for having a Python wrapper to aid in
bisection.

Anyways, I checked these options with clang 4 and gcc 4.6.4 in godbolt.
Tested-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
-- 
Thanks,
~Nick Desaulniers