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From: Jeff Law <jeffreyalaw@gmail.com>
To: Fei Gao <gaofei@eswincomputing.com>, gcc-patches@gcc.gnu.org
Cc: kito.cheng@gmail.com, palmer@dabbelt.com
Subject: Re: [PATCH 2/3] RISC-V: optimize stack manipulation in save-restore
Date: Mon, 17 Apr 2023 16:51:32 -0600	[thread overview]
Message-ID: <b8fb1f17-7e5d-5c64-f2cf-8bd96b54216e@gmail.com> (raw)
In-Reply-To: <20221201100332.22226-3-gaofei@eswincomputing.com>



On 12/1/22 03:03, Fei Gao wrote:
> The stack that save-restore reserves is not well accumulated in stack allocation and deallocation.
> This patch allows less instructions to be used in stack allocation and deallocation if save-restore enabled.
> 
> before patch:
>    bar:
>      call	t0,__riscv_save_4
>      addi	sp,sp,-64
>      ...
>      li	t0,-12288
>      addi	t0,t0,-1968 # optimized out after patch
>      add	sp,sp,t0 # prologue
>      ...
>      li	t0,12288 # epilogue
>      addi	t0,t0,2000 # optimized out after patch
>      add	sp,sp,t0
>      ...
>      addi	sp,sp,32
>      tail	__riscv_restore_4
> 
> after patch:
>    bar:
>      call	t0,__riscv_save_4
>      addi	sp,sp,-2032
>      ...
>      li	t0,-12288
>      add	sp,sp,t0 # prologue
>      ...
>      li	t0,12288 # epilogue
>      add	sp,sp,t0
>      ...
>      addi	sp,sp,2032
>      tail	__riscv_restore_4
> 
> gcc/ChangeLog:
> 
>          * config/riscv/riscv.cc (riscv_expand_prologue): consider save-restore in stack allocation.
>          (riscv_expand_epilogue): consider save-restore in stack deallocation.
> 
> gcc/testsuite/ChangeLog:
> 
>          * gcc.target/riscv/stack_save_restore.c: New test.
I made a couple of whitespace fixes and pushed this to the trunk after 
running it through a cross testing cycle.

Thanks!

jeff

  parent reply	other threads:[~2023-04-17 22:51 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-01 10:03 [PATCH 0/3] " Fei Gao
2022-12-01 10:03 ` [PATCH 1/3] RISC-V: add a new parameter in riscv_first_stack_step Fei Gao
2023-02-03  8:52   ` [PING][PATCH " Fei Gao
2023-04-16 16:40   ` [PATCH " Jeff Law
2023-04-17 18:09   ` Jeff Law
2022-12-01 10:03 ` [PATCH 2/3] RISC-V: optimize stack manipulation in save-restore Fei Gao
2023-02-03  8:52   ` [PING] " Fei Gao
2023-04-16 16:45   ` Jeff Law
2023-04-17 22:51   ` Jeff Law [this message]
2022-12-01 10:03 ` [PATCH 3/3] RISC-V: make the stack manipulation codes more readable Fei Gao
2023-02-03  8:52   ` [PING] " Fei Gao
2023-04-18  0:14   ` Jeff Law
2023-02-03  8:52 ` [PING] [PATCH 0/3] RISC-V: optimize stack manipulation in save-restore Fei Gao
2023-02-09  2:21   ` [PING 2] " Fei Gao
2023-02-16  7:17   ` Fei Gao
2023-02-16 14:39     ` Jeff Law

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