[jdk11u-dev] RFR: 8262017: C2: assert(n != __null) failed: Bad immediate dominator info.

[Martin Doerr]

Backport of JDK-8262017. Min/Max computation code taken from JDK-8244504. Removed additional bool parameter from set_subtree_ctrl because JDK-8256655 is not in 11u (loopTransform.cpp).

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

Commit messages:
 - Backport 2db9005c07585b580b3ec0889b8b5e3ed0d0ca6a

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/156/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=156&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8262017
  Stats: 312 lines in 4 files changed: 300 ins; 4 del; 8 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/156.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/156/head:pull/156

PR: https://git.openjdk.java.net/jdk11u-dev/pull/156