RFR: 8279225: C1 longs comparison operation destroys argument registers [v2]

[Sergey Nazarkin]

On Mon, 27 Dec 2021 10:52:33 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> src/hotspot/cpu/arm/c1_LIRAssembler_arm.cpp line 1823:
>> 
>>> 1821:         __ teq(xlo, ylo, eq);
>>> 1822:       } else {
>>> 1823:         __ cmp(xlo, ylo);
>> 
>> nit: we may want to use `__ subs(Rtemp, xlo, ylo);` here to align with the usage in match rules in arm.ad, e.g., `compL_reg_reg_LEGT`. It's okay to me if you use `cmp` anyway.
>
> I agree.

Aligned with C2  implementation

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PR: https://git.openjdk.java.net/jdk/pull/6934