review (XS) for 6982533: Crash in ~StubRoutines::jbyte_fill with AggressiveOpts enabled

[Vladimir Kozlov]

Looks good but could we also check (in assert?) that address type is array pointer?

Thanks,
Vladimir

Tom Rodriguez wrote:
> http://cr.openjdk.java.net/~never/6982533
> 
> 6982533: Crash in  ~StubRoutines::jbyte_fill with AggressiveOpts enabled
> Reviewed-by:
> 
> The logic for matching a byte fill is missing a check for the use of
> the index.  It normally happens as part of the check for a shift
> expression but since a byte array doesn't have a shift the check is
> missed.  The fix is to make the index check explicit.  The reason it
> didn't always crash was because of differences in heap size caused by
> ergonomics.  With a 16m heap it crashes on any machine.  Tested with
> failing test case.
> 
> src/share/vm/opto/loopTransform.cpp