Integrated: 8341893: AArch64: Micro-optimize compressed ptr decoding

[Aleksey Shipilev]

On Thu, 10 Oct 2024 07:57:14 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> See the bug for full description. I think there is an accidental inefficiency in decoding: we don't have to shift when shift is zero, but we are tripped by `d != s` check. Other architectures seem to do this right. This fix surgically fixes the decoding. I have a variant of a more comprehensive MacroAssembler fix that could cover this shift-to-mov translation wholesale, but that fix is riskier.
> 
> Additional testing:
>  - [x] Linux AArch64 server fastdebug, `tier{1,2,3}`

This pull request has now been integrated.

Changeset: e3f65039
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/e3f650393744790e24820b2d6d99dd1da1a44de6
Stats:     3 lines in 1 file changed: 2 ins; 0 del; 1 mod

8341893: AArch64: Micro-optimize compressed ptr decoding

Reviewed-by: aph, fyang

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PR: https://git.openjdk.org/jdk/pull/21443