Integrated: 8360775: Fix Shenandoah GC test failures when APX is enabled

[Srinivas Vamsi Parasa]

On Fri, 27 Jun 2025 00:02:08 GMT, Srinivas Vamsi Parasa <sparasa at openjdk.org> wrote:

> This PR fixes the test failures seen in many JTreg tests related to Shenandoah GC (`test/hotspot/jtreg/gc/shenandoah/`) with UseAPX. The issues were root caused to: 
> 
> 1. Higher band registers are not saved and restored in Shenandoah load_reference_barrier. 
> 2. Pusha/Popa implementation using push2p/pop2p does not restore the contents of rax.
> 
> Both the issues are fixed in this PR.

This pull request has now been integrated.

Changeset: 1c560727
Author:    Srinivas Vamsi Parasa <sparasa at openjdk.org>
Committer: Sandhya Viswanathan <sviswanathan at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/1c560727b850593561982ccc3ed37b0e98b3bbee
Stats:     41 lines in 2 files changed: 40 ins; 0 del; 1 mod

8360775: Fix Shenandoah GC test failures when APX is enabled

Reviewed-by: sviswanathan, jbhateja, epeter

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PR: https://git.openjdk.org/jdk/pull/26009