[riscv-port] Integrated: 8278337: riscv: remove unnecessary ld/sd zr around calls

[kuaiwei]

On Tue, 7 Dec 2021 11:21:00 GMT, kuaiwei <duke at openjdk.java.net> wrote:

> It seems zr(x0) is used as stack alignment when saving/restoring registers around calls. But it's unnecessary to ld/st x0 from/to stack. We just need reserve a stack slot in case alignment is required. It passed tier1 tests with fastdebug in qemu.

This pull request has now been integrated.

Changeset: 1a437757
Author:    kuaiwei.kw <kuaiwei.kw at alibaba-inc.com>
Committer: Fei Yang <fyang at openjdk.org>
URL:       https://git.openjdk.java.net/riscv-port/commit/1a437757945ae61524d47e300e0395c02270e18a
Stats:     20 lines in 2 files changed: 4 ins; 10 del; 6 mod

8278337: riscv: remove unnecessary ld/sd zr around calls

Reviewed-by: fyang

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PR: https://git.openjdk.java.net/riscv-port/pull/25