[lworld] RFR: 8377480: [lworld] incorrect execution due to EA pointer comparison optimization at scalarized call [v2]

[Dan Heidinga]

On Thu, 12 Feb 2026 09:31:58 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> src/hotspot/share/opto/escape.cpp line 2150:
>> 
>>> 2148:       }
>>> 2149:       _i_sig_cc++;
>>> 2150:     }
>> 
>> Is it worth tracking the previous BasicType from the signature rather than reaching back with the `_i_sig_cc-1`?  
>> 
>> Something like:
>> Suggestion:
>> 
>>    BasicType prev_bt = T_VOID;
>>     while (_i_sig_cc < _sig_cc->length()) {
>>       BasicType bt = _sig_cc->at(_i_sig_cc)._bt;
>>       if (bt == T_METADATA) {
>>         _depth++;
>>       } else if (bt == T_VOID && (prev_bt != T_LONG && prev_bt != T_DOUBLE)) {
>>         _depth--;
>>         if (_depth == 0) {
>>           _i_domain++;
>>         }
>>       } else {
>>         return;
>>       }
>>       prev_bt = bt;
>>       _i_sig_cc++;
>>     }
>
> I pushed a new commit that does that.
> When  `_sig_cc->at(_i_sig_cc)._bt = T_LONG`, the method exits. So next time it's called, with the suggested code above, `prev_bt` is not set to `T_LONG`, the way it should. The `prev_bt` initialization is slightly more complicated as a result.

Thanks.  Looks good to me

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PR Review Comment: https://git.openjdk.org/valhalla/pull/2079#discussion_r2799004141