RFR: 8332268: C2: Add missing optimizations for UDivI/L and UModI/L and unify the shared logic with the signed nodes [v17]

theoweidmannoracle duke at openjdk.org
Mon Dec 2 16:38:03 UTC 2024


> This PR introduces
> - several new optimizations to unsigned division and modulo
>    - x % 1, x % x, x % 2^k
>    - x / 1, x / x, x / 2^k 
>    - does not implement the Granlund and Montgomery algorithm, which has been implemented for signed modulo division in the past. It is unclear if a lot is to be gained by implementing this.
> - tests to test existing optimizations for signed division and modulo 
>    - does not test the Granlund and Montgomery algorithm directly

theoweidmannoracle has updated the pull request incrementally with two additional commits since the last revision:

 - Update UDivINodeIdealizationTests.java
 - Remove more magic numbers

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/22061/files
  - new: https://git.openjdk.org/jdk/pull/22061/files/8e709eb0..621cf4d1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22061&range=16
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22061&range=15-16

  Stats: 6 lines in 2 files changed: 2 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/22061.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22061/head:pull/22061

PR: https://git.openjdk.org/jdk/pull/22061


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