The report for 6589823 includes a test case which fails with meet not symmetric but it's failing for different reasons.  From the comments of that report:

Please see Tester.java class generated by JITTester which fails the same
way starting from HS12-b03 (jdk7b26). The error is:

=== Meet Not Symmetric ===
t   =                   narrowoop: Tester_Class_2:TopPTR:exact *[int:48]:AnyNull:exact *,iid=-58
this=                   Tester_Class_0:AnyNull *
mt=(t meet this)=       java/lang/Object:NotNull:exact *,iid=-58
t_dual=                 narrowoop: Tester_Class_2:exact *[int:48]:NotNull:exact *,iid=58
this_dual=              Tester_Class_0:NotNull *
mt_dual=                java/lang/Object:AnyNull:exact *,iid=58
mt_dual meet t_dual=    narrowoop: Tester_Class_2:exact *[int:48]:NotNull:exact *
mt_dual meet this_dual= java/lang/Object:NotNull *
# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc:  SuppressErrorAt=/type.cpp:541
#
# A fatal error has been detected by the Java Runtime Environment:
#
#  Internal Error (/BUILD_AREA/jdk7/hotspot/src/share/vm/opto/type.cpp:541), pid=12905, tid=1083214144
#  Error: meet not symmetric
#


The problem is not reproduced with HS12-b01 (jdk7b25).
The problem is -XX:+AggressiveOpts specific.

To reproduce the problem do something like:
1. ssh linux-amd64 machine
2. javac Tester.java
3. /net/sqenfs-1.sfbay/export1/jdk/re/7/promoted/all/b27/binaries/linux-amd64/fastdebug/bin/java  -Xcomp -d64 -server  -XX:+AggressiveOpts Tester

Running with +DoEscapeAnalysis alone it fails like this with current c2_baseline:

java -d64 -XX:+DoEscapeAnalysis -Xcomp Tester                             VM option '+DoEscapeAnalysis'
=== Meet Not Symmetric ===
t   =                   Tester_Class_2:TopPTR:exact *[int:48]:AnyNull:exact *,iid=-55
this=                   Tester_Class_0:AnyNull *
mt=(t meet this)=       java/lang/Object:NotNull:exact *,iid=-55
t_dual=                 Tester_Class_2:exact *[int:48]:NotNull:exact *,iid=55
this_dual=              Tester_Class_0:NotNull *
mt_dual=                java/lang/Object:AnyNull:exact *,iid=55
mt_dual meet t_dual=    Tester_Class_2:exact *[int:48]:NotNull:exact *
mt_dual meet this_dual= java/lang/Object:NotNull *
# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc:  SuppressErrorAt=/type.cpp:552
#
# A fatal error has been detected by the Java Runtime Environment:
#
#  Internal Error (/net/smite.sfbay/export/ws/baseline/src/share/vm/opto/type.cpp:552), pid=16221, tid=9
#  Error: meet not symmetric
#
# Java VM: OpenJDK 64-Bit Server VM (13.0-b01-never-baseline-jvmg compiled mode solaris-sparc )
# An error report file with more information is saved as:
# /never/hs_err_pid16221.log
#
# If you would like to submit a bug report, please visit:
#   http://java.sun.com/webapps/bugreport/crash.jsp
#
Current thread is 9
Dumping core ...
Abort (core dumped)

I think the problem is that mt, which is the value we're going to return, has an instance id which seems like it should have been stripped during the meet.