RFR: 8373999: C2: apply KnownBits and unsigned bounds to Add / Sub operations

Thu Dec 18 11:51:41 UTC 2025

Hi,

This PR improves the implementation of `AddNode/SubNode::Value` by taking advantage of the additional information in `TypeInt`. The implementation has some pretty non-trivial logic. Fortunately, the test infrastructure is already there.

Please take a look and leave your reviews, thanks a lot.

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Commit messages:
 - Improve Add/SubNode::Value with unsigned bounds and known bits

Changes: https://git.openjdk.org/jdk/pull/28897/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28897&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8373999
  Stats: 309 lines in 4 files changed: 235 ins; 66 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/28897.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28897/head:pull/28897

PR: https://git.openjdk.org/jdk/pull/28897