RFR (XS) 7901097: Blackhole methods should be non-inlined

[Aleksey Shipilev]

On 11/13/2014 08:34 PM, Gilles Duboscq wrote:
> An other interesting option would be to have blackhole methods in
> WhiteBox or Unsafe or similar which compilers can intrinsify to pin a
> synthetic usage of the consumed value in the CFG. This would have a
> minimal overhead (no code at all).

Yes, Sergey wondered about the same. I think CODETOOLS-7901098 will
allow implementing that without forcing a choice on us.

> However, that would only ensure the value is consumed if there are no
> further optimizations at a lower level (in the CPU for example). Are
> you aware of such optimizations in any interesting platform?

I speculated hardware may drop the operations early if it detects the
result is unclaimed (e.g. is stored to a register which is then
overwritten right away). However, I have yet to see/construct such an
example.

-Aleksey.