Ping Re: Avoid some left-shifts of negative constants

[Joseph Myers]

Ping.  Does anyone else wish to comment on this patch 
<https://sourceware.org/ml/libc-alpha/2019-02/msg00177.html> as a cleanup 
in this particular case (where as discussed, in any case -1U would be 
problematic because of a change of types, -1 would be problematic as well 
because of possible shifts by 32 or more)?

-- 
Joseph S. Myers
joseph@codesourcery.com