RFR: 8302459: Missing late inline cleanup causes compiler/vectorapi/VectorLogicalOpIdentityTest.java IR failure [v2]
Damon Fenacci
dfenacci at openjdk.org
Wed Dec 4 07:24:04 UTC 2024
> # Issue
>
> The `compiler/vectorapi/VectorLogicalOpIdentityTest.java` has been failing because C2 compiling the test `testAndMaskSameValue1` expects to have 1 `AndV` nodes but it has none.
>
> # Cause
>
> The issue has to do with the criteria that trigger a cleanup when performing late inlining. In the failing test, when the compiler tries to inline a `jdk.internal.vm.vector.VectorSupport::binaryOp` call, it fails because its argument is of the wrong type, mainly because some cast nodes “hide” the more “precise” type.
> The graph that leads to the issue looks like this:
> 
> The compiler tries to inline `jdk.internal.vm.vector.VectorSupport::load` and it succeeds:
> 
> The node `3027 VectorBox` has type `IntMaxVector`. `912 CastPP` and `934 CheckCastPP` have type `IntVector`instead.
> The compiler then tries to inline one of the 2 `bynaryOp` calls but it fails because it needs an argument of type `IntMaxVector` and the argument it is given, which is node `934 CheckCastPP` , has type `IntVector`.
>
> This would not happen if between the 2 inlining attempts a _cleanup_ was triggered. IGVN would run and the 2 nodes `912 CastPP` and `934 CheckCastPP` would be folded away. `binaryOp` could then be inlined since the types would match.
>
> # Solution
>
> Instead of fixing this specific case we try a more generic approach: when late inlining we keep track of failed intrinsics and re-examine them during IGVN. If the `Ideal` method for their call node is called, we reschedule the intrinsic attempt for that call.
>
> Additional test runs with `-XX:-TieredCompilation` are added to `VectorLogicalOpIdentityTest.java` and `VectorGatherMaskFoldingTest.java` as regression tests and `-XX:+IncrementalInlineForceCleanup` is removed from `VectorGatherMaskFoldingTest.java` (previously added as workaround for this issue)
Damon Fenacci has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 28 commits:
- Merge branch 'master' into JDK-8302459-new
- JDK-8302459: remove unneeded copyright year change
- JDK-8302459: add failed late inlines handling to dynamic calls
- JDK-8032459: fix indentation
- JDK-8302459: copyright year
- JDK-8302459: simplify late inline failure conditions
- JDK-8302459: revert unneeded copyright update
- JDK-8302459: remove unneeded spaces
- JDK-8302459: increment MH late inline counter when reinserting them
- Merge branch 'master' into JDK-8302459-new
- ... and 18 more: https://git.openjdk.org/jdk/compare/4fbf2720...7a4ffc11
-------------
Changes: https://git.openjdk.org/jdk/pull/21682/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21682&range=01
Stats: 105 lines in 7 files changed: 48 ins; 8 del; 49 mod
Patch: https://git.openjdk.org/jdk/pull/21682.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/21682/head:pull/21682
PR: https://git.openjdk.org/jdk/pull/21682
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