[riscv-port] RFR: 8282328: riscv: Intrinsify bigIntegerRightShift

[Fei Yang]

On Wed, 2 Mar 2022 03:00:07 GMT, Taiping Guo <tguo at openjdk.org> wrote:

> BigInteger intrinsic: bigIntegerRightShift intrinsic is missed in current vm. It should be implemented.
> Since that there is no hardware that supports rvv1.0 for now, I used test/jdk/java/math/BigInteger/ModPow.java testcase to compare the number of instructions executed with and without intrinsic. The number of instructions executed for the method shiftRightImplWorker compiled by C2 without intrinsic is about 8.6x ( vlen=256 ) that of version with intrinsic.
> 
> Full jtreg tests on qemu are passed without new failures.

OK.

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Marked as reviewed by fyang (Lead).

PR: https://git.openjdk.java.net/riscv-port/pull/63