RFR: 8281429: PhiNode::Value() is too conservative for tripcount of CountedLoop [v2]

[Roland Westrelin]

On Tue, 22 Mar 2022 10:41:32 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

>> Roland Westrelin has updated the pull request incrementally with four additional commits since the last revision:
>> 
>>  - Update src/hotspot/share/opto/cfgnode.cpp
>>    
>>    Co-authored-by: Tobias Hartmann <tobias.hartmann at oracle.com>
>>  - Update src/hotspot/share/opto/cfgnode.cpp
>>    
>>    Co-authored-by: Tobias Hartmann <tobias.hartmann at oracle.com>
>>  - Update src/hotspot/share/opto/loopnode.cpp
>>    
>>    Co-authored-by: Tobias Hartmann <tobias.hartmann at oracle.com>
>>  - Update src/hotspot/share/opto/loopnode.cpp
>>    
>>    Co-authored-by: Tobias Hartmann <tobias.hartmann at oracle.com>
>
> src/hotspot/share/opto/cfgnode.cpp line 1129:
> 
>> 1127:                   julong diff = (uhi - ulo - 1) / (-stride_t->lo_as_long()) * (-stride_t->lo_as_long());
>> 1128:                   julong ufirst = hi->lo_as_long() - diff;
>> 1129:                   first = reinterpret_cast<jlong &>(ufirst);
> 
> Could we also use a `static_cast` here and further down instead?

Thanks for looking at this.
I'm not sure. I modeled this code on java_add/java_substract etc.

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PR: https://git.openjdk.java.net/jdk/pull/7823