[lworld] RFR: 8328699: [lworld] C2 compilation fails with "no reachable node should have no use" [v2]

[Tobias Hartmann]

> `InlineTypeNode::set_*` methods should use `set_req_X` instead of `set_req` to make sure that an input node becoming dead is processed by IGVN.
> 
> Edit: I just noticed that the barrier part of JDK-8328682 causes some issues so I'm using this change to quickly back it out. Will REDO with JDK-8328704.
> 
> Thanks,
> Tobias

Tobias Hartmann has updated the pull request incrementally with two additional commits since the last revision:

 - Added TODO
 - Backout of 8328682 which causes issues

-------------

Changes:
  - all: https://git.openjdk.org/valhalla/pull/1055/files
  - new: https://git.openjdk.org/valhalla/pull/1055/files/1d2e15db..fcc21adb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1055&range=01
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1055&range=00-01

  Stats: 5 lines in 2 files changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1055.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1055/head:pull/1055

PR: https://git.openjdk.org/valhalla/pull/1055