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From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/97756] [9/10/11/12 Regression] Inefficient handling of 128-bit arguments
Date: Mon, 30 Aug 2021 05:18:43 +0000 [thread overview]
Message-ID: <bug-97756-4-GcMdLhQC0q@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-97756-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97756
--- Comment #7 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Patrick Palka from comment #3)
> Perhaps related to this PR: On x86_64, the following basic wrapper around
> int128 addition
>
> __uint128_t f(__uint128_t x, __uint128_t y) { return x + y; }
>
> gets compiled (/w -O3, -O2 or -Os) to the seemingly suboptimal
>
> movq %rdi, %r9
> movq %rdx, %rax
> movq %rsi, %r8
> movq %rcx, %rdx
> addq %r9, %rax
> adcq %r8, %rdx
> ret
>
> Clang does:
>
> movq %rdi, %rax
> addq %rdx, %rax
> adcq %rcx, %rsi
> movq %rsi, %rdx
> retq
Remove addti3/ashlti3 from i386.md also helps this.
next prev parent reply other threads:[~2021-08-30 5:18 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-08 19:53 [Bug rtl-optimization/97756] New: " tkoenig at gcc dot gnu.org
2020-11-09 6:29 ` [Bug rtl-optimization/97756] " tkoenig at gcc dot gnu.org
2020-12-25 11:35 ` tkoenig at gcc dot gnu.org
2021-03-10 12:55 ` ppalka at gcc dot gnu.org
2021-04-28 4:58 ` pinskia at gcc dot gnu.org
2021-04-28 7:20 ` [Bug rtl-optimization/97756] [9/10/11/12 Regression] " jakub at gcc dot gnu.org
2021-06-01 8:18 ` rguenth at gcc dot gnu.org
2021-08-30 5:18 ` crazylht at gmail dot com [this message]
2022-05-27 9:43 ` [Bug rtl-optimization/97756] [10/11/12/13 " rguenth at gcc dot gnu.org
2022-06-28 10:42 ` jakub at gcc dot gnu.org
2023-07-07 10:38 ` [Bug rtl-optimization/97756] [11/12/13/14 " rguenth at gcc dot gnu.org
2023-07-13 21:09 ` pinskia at gcc dot gnu.org
2023-07-16 11:48 ` tkoenig at gcc dot gnu.org
2023-11-07 18:38 ` tkoenig at gcc dot gnu.org
2023-11-13 9:06 ` cvs-commit at gcc dot gnu.org
2023-11-13 17:52 ` tkoenig at gcc dot gnu.org
2023-11-14 12:20 ` cvs-commit at gcc dot gnu.org
2024-04-26 12:54 ` [Bug rtl-optimization/97756] [11/12/13 " roger at nextmovesoftware dot com
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