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 15:15:25 PST 2010

Thanks.  I fixed the class name and ran it with jtreg to confirm that it works.

On Feb 17, 2010, at 3:03 PM, Vladimir Kozlov wrote:

> Looks good.
> The main test class is called Tester - not Test6663854:
> public class Tester {
> Vladimir
> Tom Rodriguez wrote:
>> Oops.
>> tom
>> 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/

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