[aarch64-port-dev ] [8u] RFR: JDK-8257192: Integrate AArch64 JIT port into 8u

[Andrew Haley]

On 11/27/20 12:12 PM, Andrew Haley wrote:
> On 11/27/20 8:43 AM, Aleksey Shipilev wrote:
>> On 11/27/20 8:33 AM, Andrew Hughes wrote:
>>> On 07:21 Fri 27 Nov     , Andrew Hughes wrote:
>>>> Umbrella Bug: https://bugs.openjdk.java.net/browse/JDK-8257192
>>>> Webrevs:
>>>>    jdk: https://cr.openjdk.java.net/~andrew/openjdk8/8257192/jdk/webrev.01/
>>
>> *) src/share/vm/adlc/formssel.cpp:
>>    - equivalent_predicates addition changes the shared code path. Is this a bugfix?
> 
> It's necessary because only on AArch64 do we need to distinguish matcher
> rules for loads and stores based on their predicates. Unfortunately this
> caused performance regressions on SPARC (on Unsafe, IIRC.)

Just a correction: this is actually 8145438, Guarantee failures since
8144028: Use AArch64 bit-test instructions in C2, which is to do with far
and near branches.

We still need to make the "&& equivalent_predicates(this, short_branch)"
AArch64-only so as not to degrade SPARC.

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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