RFR: 8227407: ZGC: C2 loads and load barriers can get separated by safepoints

[Stuart Monteith]

Hi Erik,
  I tried applying your patch from:
    http://cr.openjdk.java.net/~eosterlund/8227407/webrev.03/

and get:
   patch: **** malformed patch at line 345:    // LoadNode::hash()
doesn't take the _control_dependency field

If I change the "17" to "18" it does apply successfully:
 @@ -152,18 +152,16 @@

It is line 323 in the webrev.patch.
That the line count from before is incorrect is odd. This was applied
to a fresh repository this morning.


The aarch64 code seems fine with the 02 patch, running tier1 tests and
some other workloads.

Thanks for adding the verification.

BR,
 Stuart

On Mon, 22 Jul 2019 at 17:51, Erik Österlund <erik.osterlund at oracle.com> wrote:
>
> Hi Roland,
>
> How about UnknownControl? "Dependency" is kind of implied by the enum type.
>
> Webrev:
> http://cr.openjdk.java.net/~eosterlund/8227407/webrev.03/
>
> Incremental:
> http://cr.openjdk.java.net/~eosterlund/8227407/webrev.02_03/
>
> What do you think?
>
> Thanks,
> /Erik
>
> On 2019-07-22 16:57, Roland Westrelin wrote:
> >
> >> How would you feel about adding a new enum value for UnsafePinned, and
> >> modifying the LoadNode::Ideal transformation to
> >> explicitly allow the floating if the !depends_only_on_test() ||
> >> is_unsafe_pinned()?
> >
> > That's fine with me but the name UnsafePinned wouldn't work because
> > Pinned is currently used for one thing other than unsafe: some arraycopy
> > related optimizations. UnknownControlDependency or something shorter?
> >
> > Roland.
> >