[stable request] give up on gcc ilog2() constant optimizations

[Jiri Slaby <jslaby@xxxxxxx>]

Hi,

can we have:
commit 474c90156c8dcc2fa815e6716cc9394d7930cb9c
Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Date:   Thu Mar 2 12:17:22 2017 -0800

    give up on gcc ilog2() constant optimizations

in stable trees as far as it applies? It allows building by gcc7 on some
configs.

thanks,
-- 
js
suse labs