From: Jeff Law <jeffreyalaw@gmail.com>
To: liuhongt <hongtao.liu@intel.com>, gcc-patches@gcc.gnu.org
Cc: vmakarov@redhat.com, linkw@gcc.gnu.org, segher@kernel.crashing.org
Subject: Re: [PATCH] Only use NO_REGS in cost calculation when !hard_regno_mode_ok for GENERAL_REGS and mode.
Date: Fri, 19 May 2023 15:31:44 -0600 [thread overview]
Message-ID: <37637566-5943-fe3d-3741-b246ec954b23@gmail.com> (raw)
In-Reply-To: <20230517065702.2935000-1-hongtao.liu@intel.com>
On 5/17/23 00:57, liuhongt via Gcc-patches wrote:
> r14-172-g0368d169492017 replaces GENERAL_REGS with NO_REGS in cost
> calculation when the preferred register class are not known yet.
> It regressed powerpc PR109610 and PR109858, it looks too aggressive to use
> NO_REGS when mode can be allocated with GENERAL_REGS.
> The patch takes a step back, still use GENERAL_REGS when
> hard_regno_mode_ok for mode and GENERAL_REGS, otherwise uses NO_REGS.
> Kewen confirmed the patch fixed PR109858, I vefiried it also fixed PR109610.
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> No big performance impact for SPEC2017 on icelake server.
> Ok for trunk?
>
> gcc/ChangeLog:
>
> * ira-costs.cc (scan_one_insn): Only use NO_REGS in cost
> calculation when !hard_regno_mode_ok for GENERAL_REGS and
> mode, otherwise still use GENERAL_REGS.
BTW, Vlad is on PTO right now. I'm sure he'll handle this after he
returns and starts digging out of all the stuff that's piled up.
jeff
next prev parent reply other threads:[~2023-05-19 21:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-17 6:57 liuhongt
2023-05-19 21:31 ` Jeff Law [this message]
2023-05-25 14:29 ` Vladimir Makarov
2023-05-25 15:37 ` Segher Boessenkool
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