review (S) for 6663854: assert(n != __null,"Bad immediate dominator info.") in C2 with -Xcomp

Tom Rodriguez Thomas.Rodriguez at Sun.COM
Wed Feb 17 14:51:29 PST 2010



On Feb 17, 2010, at 2:30 PM, Tom Rodriguez wrote:

> 6663854: assert(n != __null,"Bad immediate dominator info.") in C2 with -Xcomp
> Reviewed-by:
> This is another instance of the ConvI2L problem with type information
> being raised to a point that it's no longer true, like the bug
> 6659207, resulting in top being returned and some code path being
> mistakenly killed.  The same style of fix for 6659207 won't work in
> this case because there's no option to bailout if the types won't
> work.  Instead we strip the constrained type off the ConvI2L as it is
> pushed up.  The test case was automatically generated and I couldn't
> simplify it any further so it's pretty horrific looking.  Tested with
> test case and confirmed that stripping the type doesn't affect the
> code quality for scimark which is very sensitive to the loss of the
> type information on ConvI2Ls used in address expressions.
> src/share/vm/opto/split_if.cpp
> test/compiler/6663854/

More information about the hotspot-compiler-dev mailing list