From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-x234.google.com (mail-lj1-x234.google.com [IPv6:2a00:1450:4864:20::234]) by sourceware.org (Postfix) with ESMTPS id F3F6A3858D32 for ; Thu, 25 May 2023 11:35:49 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org F3F6A3858D32 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-lj1-x234.google.com with SMTP id 38308e7fff4ca-2af98eb6ef0so5028621fa.3 for ; Thu, 25 May 2023 04:35:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1685014548; x=1687606548; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=LlNjPuhc+cGc/dCvRMqb9c3cnBRSboCMg/BH2BTk9Q0=; b=qb4d1HRRDGYSYS+Nbjpaq/7N4SWdMVoktCLS7WBSPLK8YH+Y2iNgHTAwoVf/thV+R+ mC0+y+UKRxVaVmuhc3wnZHqcyyhBCRAxgp0aztl7dkud+3WSWgw3JXYAkIxM1qupStJi pOOkbS2/DmunXOGySv11EqoO0HUB7TMijKBzYODKQBRdYgzWXkDhfwL351Sl0RX5hqPF H6F9IZDE6r3LHRglL1xmwPMfzUXHPWm6UR1KH5qYNgdw4mDO2RuYrbosz0KiW5l/s5uE JOEUOwJ7LPU0EZFngel+WlX1AwbjXl+/f8SPr03PyuXmgJpk+8I2iExZcZGpDHOVLAG2 Ohnw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685014548; x=1687606548; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=LlNjPuhc+cGc/dCvRMqb9c3cnBRSboCMg/BH2BTk9Q0=; b=WB5hyzaGslB+3yGJvegaGBFKN/rKaulr17bgnLYGk8l+XAQXGPurHYrhjdpjMoYy7Y ZB5Mt0nN7vn/JqNqVHP78dyDtnr7iKDo/06/BppopnhMlgSy6X7gEpzzr5kDcVA3vuRb MSTtS+iTvmSrrX8FQaE7VOdQeddfV+HB4QCx3a4fNQ+p2559Yh/bfCKhE1QtwTJ5NRlZ 3DVaM9rQG1/L9M/zcrFuU9MXV3Y2LWob0ysVZlF2dJrOYRvupdwfMFiMcENS4QTCrdiQ uHi3TOgnjzXBdU6RyspNmEt394T+wnWLb1rafDAspbpb7FEjuORyA30tRbULV8hlykPh nHOA== X-Gm-Message-State: AC+VfDxNWfwQt2aD/WCjTFdpISGAorTvCVONmyMOxea8xtEJ5Se+X38q SE/yPO+kjTnUngFts8wzRZU+Do42zy9zwHD4CCw= X-Google-Smtp-Source: ACHHUZ6eLRggJEy0gbz87VXeOfvRhttuov7JJL4z+oegP4cb/Kbhti1m1Jne4qt2L0RgWapDUT/K9aw8bxD6SikH83k= X-Received: by 2002:a2e:9c49:0:b0:2ad:8ffe:5f37 with SMTP id t9-20020a2e9c49000000b002ad8ffe5f37mr784942ljj.47.1685014548117; Thu, 25 May 2023 04:35:48 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Richard Biener Date: Thu, 25 May 2023 13:33:40 +0200 Message-ID: Subject: Re: [PATCH] [x86] reenable dword MOVE_MAX for better memmove inlining To: Alexandre Oliva Cc: gcc-patches@gcc.gnu.org, "H.J. Lu" , Jan Hubicka , Uros Bizjak Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-1.4 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Thu, May 25, 2023 at 1:10=E2=80=AFPM Alexandre Oliva = wrote: > > On May 25, 2023, Richard Biener wrote: > > > I mean we could do what RTL expansion would do later and do > > by-pieces, thus emit multiple loads/stores but not n loads and then > > n stores but interleaved. > > That wouldn't help e.g. gcc.dg/memcpy-6.c's fold_move_8, because > MOVE_MAX and MOVE_MAX_PIECES currently limits inline expansion to 4 > bytes on x86 without SSE, both in gimple and RTL, and interleaved loads > and stores wouldn't help with memmove. We can't fix that by changing > code that uses MOVE_MAX and/or MOVE_MAX_PIECES, when these limits are > set too low. > > I'm also concerned that doing more such expansion in gimple folding > would be reversed in later gimple passes. That's good in that it would > enable efficient rtl movmem/cpymem instruction selection, but it's not > clear to me that there would generally be benefits to such early > open-coding in gimple. Btw, there was a short period where the MOVE_MAX limit was restricted but that had fallout and we've reverted since then. Richard. > -- > Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/ > Free Software Activist GNU Toolchain Engineer > Disinformation flourishes because many people care deeply about injustice > but very few check the facts. Ask me about