[riscv-port-jdk17u:riscv-port] RFR: 8301033: RISC-V: Handle special cases for MinI/MaxI nodes for Zbb

[Fei Yang]

On Fri, 2 Jun 2023 01:55:55 GMT, Dingli Zhang <dzhang at openjdk.org> wrote:

> Hi, please review this backport to riscv-port-jdk17u.
> Backport of [JDK-8301033](https://bugs.openjdk.org/browse/JDK-8301033). Applies cleanly.
> 
> The difference in -XX:+PrintOptoAssembly output looks like:
> Before:
> 
> 048 li R7, #0 # int, #@loadConI
> 04a + max R10, R12, R7 #@maxI_reg_b
> 04e # pop frame 32
> 
> 
> After:
> 
> 048 max R10, R12, zr #@maxI_reg_zero_b
> 04c # pop frame 32
> 
> 
> Before:
> 
> 028 li R7, #0 # int, #@loadConI
> 02a + min R10, R11, R7 #@minI_reg_b
> 02e # pop frame 32
> 
> 
> After:
> 
> 028 min R10, R11, zr #@minI_reg_zero_b
> 02c # pop frame 32
> 
> 
> Testing:
> - https://github.com/openjdk/jdk/blob/master/test/hotspot/jtreg/compiler/intrinsics/math/TestMinMaxIntrinsics.java
> - tier1-3 tests on QEMU-System w/ and w/o UseZbb (release build)
> - tier1-3 tests on unmatched board w/o UseZbb (release build)

Marked as reviewed by fyang (Lead).

-------------

PR Review: https://git.openjdk.org/riscv-port-jdk17u/pull/66#pullrequestreview-1456570771