RFR: 8314117: RISC-V: Incorrect VMReg encoding in RISCV64Frame.java

[Fei Yang]

On Thu, 10 Aug 2023 14:01:25 GMT, Feilong Jiang <fjiang at openjdk.org> wrote:

> Hi, inspired by [JDK-8247351](https://bugs.openjdk.org/browse/JDK-8247351),  this patch fixes a VMReg encoding issue in `RISCV64Frame.java`. As the VMReg has two slots in a 64-bit VM, the encoding of `fp` should be `8 << 1` instead of `8`.
> 
> Testing:
> - [x] tier1 with release build
> - [ ] tier2 with release build
> - [ ] tier3 with release build

Looks reasonable to me. Thanks for finding this.

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Marked as reviewed by fyang (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15226#pullrequestreview-1573086628