RFR: 8323220: Reassociate loop invariants involved in Cmps and Add/Subs [v14]
Joshua Cao
duke at openjdk.org
Fri Mar 22 18:48:56 UTC 2024
> // inv1 == (x + inv2) => ( inv1 - inv2 ) == x
> // inv1 == (x - inv2) => ( inv1 + inv2 ) == x
> // inv1 == (inv2 - x) => (-inv1 + inv2 ) == x
>
>
> For example,
>
>
> fn(inv1, inv2)
> while(...)
> x = foobar()
> if inv1 == x + inv2
> blackhole()
>
>
> We can transform this into
>
>
> fn(inv1, inv2)
> t = inv1 - inv2
> while(...)
> x = foobar()
> if t == x
> blackhole()
>
>
> Here is an example: https://github.com/openjdk/jdk/blob/b78896b9aafcb15f453eaed6e154a5461581407b/src/java.base/share/classes/java/lang/invoke/LambdaFormEditor.java#L910. LHS `1` and RHS `pos` are both loop invariant
>
> Passes tier1 locally on Linux machine. Passes GHA on my fork.
Joshua Cao has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 17 additional commits since the last revision:
- Merge branch 'master' into licm
- @run driver -> @run main
- Add tests for add/sub reassociation
- Merge branch 'master' into licm
- Make inputs deterministic. Make size an arg. Fix comments. Formatting.
- Update test to utilize @setup method for arguments
- Merge branch 'master' into licm
- Add correctness test for some random tests with random inputs
- Add some correctness tests where we do reassociate
- Remove unused TestInfo parameter. Have some tests exit mid-loop.
- ... and 7 more: https://git.openjdk.org/jdk/compare/aac43a2d...32cb9c0d
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/17375/files
- new: https://git.openjdk.org/jdk/pull/17375/files/33e34b03..32cb9c0d
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=17375&range=13
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=17375&range=12-13
Stats: 55614 lines in 2299 files changed: 8712 ins; 5522 del; 41380 mod
Patch: https://git.openjdk.org/jdk/pull/17375.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/17375/head:pull/17375
PR: https://git.openjdk.org/jdk/pull/17375
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