Request for reviews (XS): 6866651: Regression: simple int sum crashes jvm (build 1.6.0_14-b08 and 1.7.0-ea-b59)

[John Coomes]

Tom Rodriguez (Thomas.Rodriguez at Sun.COM) wrote:
> You also don't need the /othervm part.

Minor point, but isn't it polite to use /othervm for a test that could
cause a crash?  If it's run in the same vm, a crash would bring down
the harness.

-John

> On Aug 14, 2009, at 3:09 PM, Vladimir Kozlov wrote:
> 
> > Looks good.
> >
> > I would remove -server from the test options to run it with tested
> > (client) VM instead of default VM.
> >
> > Thanks,
> > Vladimir
> >
> > changpeng fang - Sun Microsystems - Santa Clara United States wrote:
> >> http://cr.openjdk.java.net/~cfang/6866651/webrev.00/
> >> Fixed 6866651: Regression: simple int sum crashes jvm (build  
> >> 1.6.0_14-b08 and 1.7.0-ea-b59)
> >> Problem:
> >> set_req_X will do dead code elimination if the original input has  
> >> no other use. However, it is possible to
> >> have the current node (this) removed if a dead loop exists.  So,   
> >> dead code elimination in set_req_X is not
> >> safe, and may  cause undesired consequences (like the segfault in  
> >> 6866651)
> >> Solution:
> >> Instead of doing dead code elimination immediately in set_req_X, we  
> >> put the dead node (original input) into
> >> the worklist, and the dead node will eventually be eliminated when  
> >> it is its turn to be processed.
> >> In addition,  before ideal transformations, we replace a node with  
> >> a constant if we know it computes a constant
> >> to skip unneeded optimizations on this node.
> >> Tests: JPRT, CompileTheWorld, Test case in bug report (Test.java in  
> >> webrev)
> >> Thanks,
> >> Changpeng
>