RFR (S): Shenandoah matrix update barriers should be conditional

[Aleksey Shipilev]

On 03/09/2017 06:33 PM, Roman Kennke wrote:
> Out of curiousity, how do the numbers look without matrix?

I'll do that exercise when optimizing the single-threaded performance.

>> P.S. I am seriously considering to change bool* to char*, to avoid this C++ bool
>> mess.
> Please go ahead. If we ever encounter a platform that compiles bool to
> more than one byte, our matrix goes through the roof ;-)

...but this goes first!

-Aleksey