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List:       openjdk-hotspot-compiler-dev
Subject:    Integrated: 8301033: RISC-V: Handle special cases for MinI/MaxI nodes for Zbb
From:       Fei Yang <fyang () openjdk ! org>
Date:       2023-01-30 12:19:25
Message-ID: inVQnSpqAXpoAizlfN344AW__H3WxaNkZm0fk6QByBM=.6ac65d3e-0ee6-431a-b569-59147280743b () github ! com
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On Wed, 25 Jan 2023 03:40:04 GMT, Fei Yang <fyang@openjdk.org> wrote:

> The code generation for MinI/MaxI nodes for Zbb extension could be improved when \
> one of the source operands is constant 0. We can make use of the dedicated zero \
> register of the architecture for these special cases. This adds two match rules for \
> those cases. 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:
> - [x] https://github.com/openjdk/jdk/blob/master/test/hotspot/jtreg/compiler/intrinsics/math/TestMinMaxIntrinsics.java
>                 
> - [x] Tier1 tested with QEMU (Enabled support for Zbb extension)

This pull request has now been integrated.

Changeset: 61a5f114
Author:    Fei Yang <fyang@openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/61a5f114eee3a90cfff9ab8b815bacca8985c211
                
Stats:     38 lines in 1 file changed: 34 ins; 0 del; 4 mod

8301033: RISC-V: Handle special cases for MinI/MaxI nodes for Zbb

Reviewed-by: fjiang, luhenry, shade

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

PR: https://git.openjdk.org/jdk/pull/12176


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