RFR(S): 8231612: 100% cpu on arm32 in Service Thread

[Kim Barrett]

> On Nov 19, 2019, at 10:18 AM, Aleksei Voitylov <aleksei.voitylov at bell-sw.com> wrote:
> 
> Kim,
> 
> you are right, to play it safe we need to -fno-tree-pre all relevant
> bool occurrances. I'll get back with an updated webrev when testing is
> finished.

I think just sprinkling the build system with -fno-tree-pre to address this doesn’t
scale in the face of people writing new code.

I think we need to find a way to write CmpxchgByteUsingInt in such a way that
it doesn’t tickle this bug, or forbid byte-sized cmpxchg (which would be painful),
or provide some entirely other implementation approach.