RFR: 8267807: C2: Downcast receiver to target holder during inlining

[Vladimir Ivanov]

On Tue, 1 Jun 2021 07:01:19 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

> What about adding a simple test for this? Maybe by using the new IR testing framework once it's there.

Existing tests (and new CHA tests under reviews) trigger the assert in `Parse::do_field_access()` when the cast is absent:

    const TypeInstPtr *tjp = TypeInstPtr::make(TypePtr::NotNull, iter().get_declared_field_holder());
    assert(_gvn.type(obj)->higher_equal(tjp), "cast_up is no longer needed");

Once IR testing framework is integrated, it may be worth the effort to prepare a stand-alone simple test case.

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PR: https://git.openjdk.java.net/jdk/pull/4212