RFR: 8283726: x86_64 intrinsics for compareUnsigned method in Integer and Long [v3]

[Quan Anh Mai]

On Tue, 28 Jun 2022 05:51:42 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Quan Anh Mai has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   add comparison for direct value of compare
>
> src/hotspot/cpu/x86/x86_64.ad line 13027:
> 
>> 13025: // Manifest a CmpU result in an integer register.  Very painful.
>> 13026: // This is the test to avoid.
>> 13027: instruct cmpU3_reg_reg(rRegI dst, rRegI src1, rRegI src2, rFlagsReg flags)
> 
> Do you plan to add 32 bit support?
> Integer pattern can be moved to common file x86.ad and 64 pattern can handled in 32/64 bit AD files.

Yes I will add support for 32-bit after this patch, basic rules are often put in the bit-specific ad file so I think it would be more preferable to follow that convention here.

> src/hotspot/share/opto/subnode.hpp line 247:
> 
>> 245:     init_class_id(Class_Sub);
>> 246:   }
>> 247:   virtual int Opcode() const;
> 
> In-lining may connect the inputs to constant, hence a Value routine may be useful here.

`CmpU3` inherits the `Value` method from its superclass `CmpU`

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PR: https://git.openjdk.org/jdk/pull/9068