Re: [PATCH 1/2] i2c: rcar: refactor private flags

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> May I ask how exactly you spotted the "shift-31-problem" in
> drivers/i2c/busses/i2c-rcar.c:
>  - visual code review?
>  - static analysis, special compiler flags?

This one. I run a set of static code analyziers when applying patches.
One of them is 'cppcheck' which reported it.

> According to feedback from GCC community [2], with 'gcc -std=gnu89',
> shifting into (not past) the sign bit is "defined behavior" which is why
> UBSAN doesn't report this as an issue in Linux kernel. That makes me

I see. I guess it can be argued. Yet, BIT() solves other issues as well
('1' vs '1u'), so this was probably a reasonable move nonetheless, plus
we are super-super-sure about the shifting now.

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