Integrated: 8343067: C2: revisit constant-offset AddP chains after successful input idealizations

[Roberto Castañeda Lozano]

On Tue, 5 Nov 2024 10:02:16 GMT, Roberto Castañeda Lozano <rcastanedalo at openjdk.org> wrote:

> This changeset re-adds a constant-offset AddP node (`u`) to C2's IGVN worklist when its address is given by another AddP node (`use`) whose offset has changed. This makes it possible for `AddPNode::Ideal` to flatten the address computation in cases where the offset of the latter (`use->in(AddPNode::Offset)`) is found to be constant during IGVN:
> 
> ![idealization](https://github.com/user-attachments/assets/6b632642-c037-457f-bd19-6b30f24e6ac6)
> 
> The end result is the generation of fewer explicit address computation instructions.
> 
> #### Testing
> 
> ##### Functionality
> 
> - tier1-5 (linux-x64, windows-x64, macosx-x64, linux-aarch64, macosx-aarch64; release and debug mode).
> 
> ##### Performance
> 
> - Tested performance on a set of standard benchmark suites (DaCapo, SPECjbb2015, SPECjvm2008). No significant change was observed.

This pull request has now been integrated.

Changeset: ec13364c
Author:    Roberto Castañeda Lozano <rcastanedalo at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/ec13364cdab5a52f704bc5d1575f3da17380b4f2
Stats:     73 lines in 3 files changed: 70 ins; 0 del; 3 mod

8343067: C2: revisit constant-offset AddP chains after successful input idealizations

Reviewed-by: kvn, vlivanov

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PR: https://git.openjdk.org/jdk/pull/21898