[jdk20u] RFR: 8303564: C2: "Bad graph detected in build_loop_late" after a CMove is wrongly split thru phi

[Tobias Hartmann]

Backport of [JDK-8303564](https://bugs.openjdk.java.net/browse/JDK-8303564). Applies cleanly. Approval is pending.

Thanks,
Tobias

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Commit messages:
 - 8303564: C2: "Bad graph detected in build_loop_late" after a CMove is wrongly split thru phi

Changes: https://git.openjdk.org/jdk20u/pull/38/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk20u&pr=38&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8303564
  Stats: 82 lines in 2 files changed: 80 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk20u/pull/38.diff
  Fetch: git fetch https://git.openjdk.org/jdk20u.git pull/38/head:pull/38

PR: https://git.openjdk.org/jdk20u/pull/38