RFR: 8342156: C2: Compilation failure with fewer arguments after JDK-8329032

[Vladimir Kozlov]

On Mon, 21 Oct 2024 14:05:54 GMT, Daniel Lundén <dlunden at openjdk.org> wrote:

> Adding C2 register allocation support for APX EGPRs ([JDK-8329032](https://bugs.openjdk.org/browse/JDK-8329032)) reduced, due to unfortunate rounding in the register mask size computation, the available space for incoming/outgoing method arguments in register masks.
> 
> ### Changeset
> 
> - Bump the number of 32-bit words dedicated to incoming/outgoing arguments in register masks from 3 to 4.
> - Add a regression test.
> 
> ### Testing
> 
> - [GitHub Actions](https://github.com/dlunde/jdk/actions/runs/11436050131)
> - `tier1` to `tier4` (and additional Oracle-internal testing) on Windows x64, Linux x64, Linux aarch64, macOS x64, and macOS aarch64.
> - C2 compilation time benchmarking for DaCapo on Windows x64, Linux x64, Linux aarch64, macOS x64, and macOS aarch64. There is no observable difference in C2 compilation time.

Looks good. Thank you for adding test.

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

Marked as reviewed by kvn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/21612#pullrequestreview-2383167782