RFR: 8241502: C2: Migrate x86_64.ad to MacroAssembler [v8]

[Vladimir Kozlov]

On Thu, 22 Apr 2021 22:05:44 GMT, John Tortugo <github.com+2249648+JohnTortugo at openjdk.org> wrote:

>> Relates to: https://bugs.openjdk.java.net/browse/JDK-8241502
>> Tested on: Linux tier1, 2 and 3
>> 
>> Can you please take a look whether these changes are going in the direction expected or not? If it is, I'll continue working on the `JDK-8241502` but I'd like to split it in a few PRs since it's a lot of changes.
>
> John Tortugo has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix cast of constant

src/hotspot/cpu/x86/assembler_x86.cpp line 9413:

> 9411: 
> 9412: void Assembler::set_byte_if_not_zero(Register dst) {
> 9413:   emit_int24(0x0F, (unsigned char)0x95, (0xC0 | dst->encoding()));

Can you explain this change?
I see it is used only in c1_LIRAssembler_x86.cpp

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PR: https://git.openjdk.java.net/jdk/pull/2420