[jdk17u-dev] RFR: 8361117: SIGSEGV in LShiftLNode::Ideal due to unexpected dead node [v2]

[Martin Doerr]

> This is a new fix for [JDK-8361117](https://bugs.openjdk.org/browse/JDK-8361117) for OpenJDK. I can't see the corresponding fix because it's not public.
> 
> This fix is taken from https://github.com/openjdk/jdk/commit/05a0a710313917fe7124ff43fe9c9af1d649bcac.
> The problem is described in https://github.com/openjdk/jdk/blob/674cc3eeca77f1f2a6d937b1df5c5cd8a13c2d31/test/hotspot/jtreg/compiler/arraycopy/TestACSameSrcDst.java#L87 but that regression test didn't reproduce the issue in jdk17u.
> 
> I've taken the reproducer from the issue and put it into a new regression test. The VM crashes without the fix and the test passes with the fix.

Martin Doerr has updated the pull request incrementally with one additional commit since the last revision:

  Rename new test.

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

Changes:
  - all: https://git.openjdk.org/jdk17u-dev/pull/4204/files
  - new: https://git.openjdk.org/jdk17u-dev/pull/4204/files/40c63e86..3c8ec182

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=4204&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=4204&range=00-01

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/4204.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/4204/head:pull/4204

PR: https://git.openjdk.org/jdk17u-dev/pull/4204