[jdk17u-dev] Integrated: 8296545: C2 Blackholes should allow load optimizations

Tue Apr 25 20:19:25 UTC 2023

On Wed, 19 Apr 2023 13:36:37 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Unclean backport to improve Blackhole performance and match it to released JDK 20.
> The backport is unclean because there are two little conflicts:
>   1. The context conflict in `MemBarNode::make`, where the `MemBarStoreStore` was moved to another place. I resolved the conflict by hand: accepted only the `Blackhole` case removal.
>   2. IR Framework needs `MUL_I` constant for test to work.
> 
> Additional testing:
>   - [x] macos-aarch64-server-fastdebug, `compiler/irTests/blackhole` (includes new test)
>   - [x] Eyeballing perfasm outputs with/without this patch

This pull request has now been integrated.

Changeset: e1326051
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.org/jdk17u-dev/commit/e132605161ff25cdac0d993ab8ab41f75f367200
Stats:     211 lines in 8 files changed: 168 ins; 42 del; 1 mod

8296545: C2 Blackholes should allow load optimizations

Reviewed-by: mdoerr
Backport-of: eab0ada3a16a432fdfd1f0b8fceca149c725451b

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PR: https://git.openjdk.org/jdk17u-dev/pull/1273