On Wed, 13 May 2026 14:34:34 GMT, Tobias Hartmann <[email protected]> wrote:
>> The original failure was in `test21` from >> `compiler/valhalla/inlinetypes/TestNullableInlineTypes.java#id5`. I >> extracted it into a standalone reproducer. >> >> C2 asserts in `InlineTypeNode::field_value_by_offset` while looking up a >> field value by offset. The lookup reaches a flat field whose corresponding >> input is already `TOP`. This happens on the normal return path from >> `test2()` in `test()`. That path is dead because `test2()` always throws a >> `NullPointerException` when it tries to initialize a null restricted field >> with null. We only "know" this after incremental inlining though. >> >> So at this point, with `-XX:+StressIGVN`, the impossible control path has >> not been removed yet, but the data path has already started dying: field >> values on the dead `InlineTypeNode` have been replaced by `TOP`. >> `InlineTypeNode::field_value_by_offset` already accounts for this with a >> `value->is_top()` check, but the offset assert in that case is too strict. >> >> In this reproducer, the lookup is recursive: it asks for a field inside a >> flat field whose value is already `TOP`. Therefore, the requested offset is >> the offset of a nested field within the flattened payload, while >> `field->offset_in_bytes()` is the offset of the enclosing flat field. Those >> offsets are not expected to match. >> >> I adjusted the assert accordingly. >> >> Thanks, >> Tobias >> >> --------- >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > Tobias Hartmann has updated the pull request incrementally with one > additional commit since the last revision: > > bug number Thanks Quan Anh! ------------- PR Comment: https://git.openjdk.org/valhalla/pull/2433#issuecomment-4457399367
