> 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 on the dead `InlineTypeNode` have been replaced by `TOP`.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: Review comments and test fix ------------- Changes: - all: https://git.openjdk.org/valhalla/pull/2433/files - new: https://git.openjdk.org/valhalla/pull/2433/files/426af5ba..741acf68 Webrevs: - full: https://webrevs.openjdk.org/?repo=valhalla&pr=2433&range=01 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=2433&range=00-01 Stats: 9 lines in 2 files changed: 5 ins; 0 del; 4 mod Patch: https://git.openjdk.org/valhalla/pull/2433.diff Fetch: git fetch https://git.openjdk.org/valhalla.git pull/2433/head:pull/2433 PR: https://git.openjdk.org/valhalla/pull/2433
