RFR(S): 8240195: some jaotc failures of fastdebug build with specific flags

[Tobias Hartmann]

Looks good to me too. The indentation in subtypenode.cpp:118 is wrong.

Best regards,
Tobias

On 09.03.20 16:42, Vladimir Kozlov wrote:
> Good.
> 
> Thanks,
> Vladimir
> 
> On 3/9/20 2:10 AM, Roland Westrelin wrote:
>>
>> Correct webrev is:
>>
>> http://cr.openjdk.java.net/~roland/8240195/webrev.00/
>>
>>> 8238691 wrongly made all subtype checks with an abstract super class
>>> which has no sub class fail. It's only valid if the subclass is loaded
>>> from an oop because no oop of an abstract class can be allocated.
>>>
>>> On an:
>>> obj instanceof klass
>>> subtype check, the SubTypeCheckNode is created with a direct edge to
>>> the obj node.
>>>
>>> So to distinguish:
>>> obj instanceof abstractKlass
>>> from:
>>> abstractKlass.class.isAssignableFrom(c)
>>> all that is needed is to check whether the input to the SubTypeCheckNode
>>> is an oop.
>>>
>>> There's one exception to this, thought. Exception handling sometimes
>>> create the following pattern:
>>> (SubTypeCheck (LoadKlass obj) ...)
>>> which must be transformed to:
>>> (SubTypeCheck obj ...)
>>> first in order to not miss an constant folding opportunity. I added that
>>> transformation in SubTypeCheckNode::Ideal().
>>>
>>> Roland.
>>