RFR: 8352893: C2: OrL/INode::add_ring optimize (x | -1) to -1
Manuel Hässig
duke at openjdk.org
Fri Mar 28 10:28:20 UTC 2025
# Issue Summary
The `add_ring()` implementations of `OrINode` and `OrLNode` are missing the optimization that an or with a value where all bits are ones (since we have signed integers in this case `~0 == -1`) will always yield all zeroes.
# Changes
This PR makes the following straight forward changes:
- `Or(I|L)Node::add_ring()` returns `-1` if one of the two inputs is `-1`.
- Add `Or(I|L)` nodes to the IR framework.
- Add a regression IR test for the implemented optimization.
# Testing
- [Github Actions](https://github.com/mhaessig/jdk/actions/runs/14110978686)
- Ran tier1 through tier3 and Oracle internal testing
-------------
Commit messages:
- Add regression test
- ir-framework: Add OrI, and OrL nodes
- OrI/OrLNode: fold x | -1
Changes: https://git.openjdk.org/jdk/pull/24289/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24289&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8352893
Stats: 108 lines in 3 files changed: 108 ins; 0 del; 0 mod
Patch: https://git.openjdk.org/jdk/pull/24289.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/24289/head:pull/24289
PR: https://git.openjdk.org/jdk/pull/24289
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