RFR: 8368303: AlwaysAtomicAccesses is excessively strict

[Albert Mingkun Yang]

On Mon, 22 Sep 2025 16:51:08 GMT, Andrew Haley <aph at openjdk.org> wrote:

> In C1, the experimental flag `AlwaysAtomicAccesses` treats accesses to all fields as if they were volatile fields. This is correct but excessive: we only need single-copy atomicity to satisfy `AlwaysAtomicAccesses`. 
> 
> We need this in order to allow progress on JDK-8365147.

I get the feeling that this "optimization" (using plain store/move for smaller types) should be done at a lower level/later stage, i.e. in respective backend.

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PR Comment: https://git.openjdk.org/jdk/pull/27432#issuecomment-3323721293