From: Jeff Law <jeffreyalaw@gmail.com>
To: Hongyu Wang <hongyu.wang@intel.com>, gcc-patches@gcc.gnu.org
Cc: richard.guenther@gmail.com, ubizjak@gmail.com, hongtao.liu@intel.com
Subject: Re: [PATCH] i386: Only enable small loop unrolling in backend [PR 107602]
Date: Mon, 21 Nov 2022 10:40:52 -0700 [thread overview]
Message-ID: <72ce55ba-2cda-6185-b89a-6d30ea95a383@gmail.com> (raw)
In-Reply-To: <20221119062532.75190-1-hongyu.wang@intel.com>
On 11/18/22 23:25, Hongyu Wang via Gcc-patches wrote:
> Hi,
>
> Followed by the discussion in pr107602, -munroll-only-small-loops
> Does not turns on/off -funroll-loops, and current check in
> pass_rtl_unroll_loops::gate would cause -funroll-loops do not take
> effect. Revert the change about targetm.loop_unroll_adjust and apply
> the backend option change to strictly follow the rule that
> -funroll-loops takes full control of loop unrolling, and
> munroll-only-small-loops just change its behavior to unroll small size
> loops.
>
> Bootstrapped and regtested on x86-64-pc-linux-gnu.
>
> Ok for trunk?
>
> gcc/ChangeLog:
>
> PR target/107602
> * common/config/i386/i386-common.cc (ix86_optimization_table):
> Enable loop unroll O2, disable -fweb and -frename-registers
> by default.
> * config/i386/i386-options.cc
> (ix86_override_options_after_change):
> Disable small loop unroll when funroll-loops enabled, reset
> cunroll_grow_size when it is not explicitly enabled.
> (ix86_option_override_internal): Call
> ix86_override_options_after_change instead of calling
> ix86_recompute_optlev_based_flags and ix86_default_align
> separately.
> * config/i386/i386.cc (ix86_loop_unroll_adjust): Adjust unroll
> factor if -munroll-only-small-loops enabled.
> * loop-init.cc (pass_rtl_unroll_loops::gate): Do not enable
> loop unrolling for -O2-speed.
> (pass_rtl_unroll_loops::execute): Rmove
> targetm.loop_unroll_adjust check.
The reversion of the loop-init.cc changes is fine. The x86 maintainers
will need to chime in on the rest. Consider installing the loop-init.cc
reversion immediately as the current state has regressed s390 and
potentially other targets.
jeff
next prev parent reply other threads:[~2022-11-21 17:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-19 6:25 Hongyu Wang
2022-11-21 1:01 ` Liu, Hongtao
2022-11-21 1:35 ` Hongtao Liu
2022-11-21 6:12 ` Hongyu Wang
2022-11-21 17:40 ` Jeff Law [this message]
2022-11-22 1:08 ` Hongtao Liu
2022-11-23 1:54 ` Hongyu Wang
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