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  1. JDK
  2. JDK-8362117

C2: compiler/stringopts/TestStackedConcatsAppendUncommonTrap.java fails with a wrong result

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      compiler/stringopts/TestStackedConcatsAppendUncommonTrap.java fails with a wrong result after stacked string concatenation optimizations when run with stress flags.

      -Xcomp -XX:CompileThreshold=100 -XX:-TieredCompilation -XX:+DeoptimizeALot

      These flags inline 'f' into the main method which is OSR compiled in the failure case (and maybe they avoid the uncommon trap that JDK-8357105 was caused by).

      This bug is hidden by JDK-8273612 since JDK 18, but to my understanding, that fix should not affect correctness, only inlining decisions for the -Xcomp mode.

      ===

      The test runs fine before JDK-8271341, then starts crashing until JDK-8291775, and after that it produces the wrong result. The failure mode looks similar to JDK-7179138 since in both cases a result with the wrong length is produced.

        1. 35_before_stringopts.png
          35_before_stringopts.png
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        2. stacked_concat_in_failure_case.png
          stacked_concat_in_failure_case.png
          282 kB

            dskantz Daniel Skantz
            dskantz Daniel Skantz
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              Created:
              Updated: