RFR: 8330853: Add missing checks for ConnectionGraph::can_reduce_cmp() call [v2]

[Vladimir Kozlov]

> In Leyden testing CI we start hitting assert:
> 
> 
> # Internal Error (/workspace/open/src/hotspot/share/opto/node.hpp:407), pid=3216007, tid=3216030
> # assert(i < _max) failed: oob: i=2, _max=2
> 
> Stack: [0x00007f20b011b000,0x00007f20b021b000], sp=0x00007f20b02157e0, free space=1001k
> Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
> V [libjvm.so+0xbf5bb4] Node::in(unsigned int) const [clone .part.0]+0x24 (node.hpp:407)
> V [libjvm.so+0xbf69ea] ConnectionGraph::can_reduce_cmp(Node*, Node*) const+0x9a (node.hpp:407)
> V [libjvm.so+0xbf74a6] ConnectionGraph::can_reduce_check_users(Node*, unsigned int) const+0x996 (escape.cpp:578)
> 
> 
> [JDK-8316991](https://bugs.openjdk.org/browse/JDK-8316991) added new code which assumes that we always have sequence : IfNode->Bool->Cmp: [escape.cpp#L569](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/escape.cpp#L569)
> which is not true in some cases. In failed cases there is additional Opaque4 node between If and Bool nodes.
> 
> The fix is to add missing checks for If, Bool and Cmp nodes.
> 
> The fix is verified in Leyden CI testing. The failure happens only with special C2 mode compilation in Leyden.

Vladimir Kozlov has updated the pull request incrementally with one additional commit since the last revision:

  Remove redundant opcode check

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/18916/files
  - new: https://git.openjdk.org/jdk/pull/18916/files/943fda52..6c19152f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18916&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18916&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/18916.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18916/head:pull/18916

PR: https://git.openjdk.org/jdk/pull/18916