RFR: 8327964: Simplify BigInteger.implMultiplyToLen intrinsic [v5]

[Yudi Zheng]

On Wed, 17 Apr 2024 19:33:01 GMT, Dean Long <dlong at openjdk.org> wrote:

>> Yudi Zheng has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   address comment.
>
> src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp line 4670:
> 
>> 4668:     const Register tmp5  = r15;
>> 4669:     const Register tmp6  = r16;
>> 4670:     const Register tmp7  = r17;
> 
> Why not minimize changes and continue to use r5 for tmp0?  I see no need for r17 or to reassign all the other tmp registers.

Was attempting to align the suffixes. Will revert.

> src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp line 4693:
> 
>> 4691:     const Register xlen  = r1;
>> 4692:     const Register z     = r2;
>> 4693:     const Register zlen  = r3;
> 
> LibraryCallKit::inline_squareToLen() is still computing zlen and passing it as the 4th arg, even though the value is unused.

ppc x86 are not using `multiply_to_len` for `generate_squareToLen`. I think we still need to pass zlen for these platforms.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18226#discussion_r1610083476
PR Review Comment: https://git.openjdk.org/jdk/pull/18226#discussion_r1610088021