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From: "kito at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/108764] [RISCV] Cost model for RVB is too aggressive
Date: Sun, 12 Feb 2023 10:08:11 +0000 [thread overview]
Message-ID: <bug-108764-4-cgYcHkmyWd@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108764-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108764
Kito Cheng <kito at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |kito at gcc dot gnu.org
--- Comment #3 from Kito Cheng <kito at gcc dot gnu.org> ---
> I think one solution is to change the cost model of such complex instructions to the sum of the cost for each part. E.g.
> cost for shNadd = COSTS_N_INSNS (SINGLE_SHIFT_COST) + COSTS_N_INSNS (1) # cost of addition
Some RISC-V core implementation did has one cycle for shNadd operation as I
know, but I know it's not true for every implementation.
Anyway, it's really uarch dependent, so I would prefer keep as it for now, and
then extend the cost model function to easier handle different uarch (-mtune)
when GCC 14 is open.
next prev parent reply other threads:[~2023-02-12 10:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-12 7:36 [Bug target/108764] New: " sinan.lin at linux dot alibaba.com
2023-02-12 7:46 ` [Bug target/108764] " sinan.lin at linux dot alibaba.com
2023-02-12 8:22 ` pinskia at gcc dot gnu.org
2023-02-12 10:08 ` kito at gcc dot gnu.org [this message]
2023-02-12 10:47 ` sinan.lin at linux dot alibaba.com
2023-02-12 11:00 ` sinan.lin at linux dot alibaba.com
2023-02-22 2:26 ` law at gcc dot gnu.org
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