-d treecheck fails to detect bad AVIS_SSAASSIGN

Bugzilla Link	702
Created on	Apr 29, 2010 22:30
Resolution	INVALID
Resolved on	May 01, 2010 20:12
Version	svn
OS	Linux
Architecture	PC

Extended Description

I had a problem in PM with SSAASSIGN chain corruption, so
ran with -d treecheck to isolate the fault. No problems reported,
yet the crash still happens.
Then, I manually entered CHKdoTreeCheck(arg_node) calls
at IVEXIfundef entry and exit: Bingo! The bad SSAASSIGN
nodes were detected properly. 
This is in my local code, so no idea if this hits the
live system: 
rev 16795:16812:MODIFIED
I got it to fail with sac/testsuite/optimizations/awlf/duplhs.sac.