RFR: 8285973: x86_64: Improve fp comparison and cmove for eq/ne [v2]

[Quan Anh Mai]

On Wed, 4 May 2022 23:16:41 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> src/hotspot/cpu/x86/x86_64.ad line 6998:
>> 
>>> 6996:   ins_encode %{
>>> 6997:     __ cmovl(Assembler::parity, $dst$$Register, $src$$Register);
>>> 6998:     __ cmovl(Assembler::notEqual, $dst$$Register, $src$$Register);
>> 
>> Should this be `equal`?
>
> I see that you swapped `src, dst` in `match()` but `format` is sill incorrect and the code is confusing.

This is a flipping the sense of the test by flipping the input of the `CMove`, so this is essentially the same as in the above rule. Thanks.

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PR: https://git.openjdk.java.net/jdk/pull/8525