From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CC45AC71153 for ; Tue, 29 Aug 2023 13:21:51 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qayeg-0003y7-UO; Tue, 29 Aug 2023 09:21:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qayee-0003vk-VJ for qemu-devel@nongnu.org; Tue, 29 Aug 2023 09:21:12 -0400 Received: from mail-lf1-x12e.google.com ([2a00:1450:4864:20::12e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qayeb-00031i-1k for qemu-devel@nongnu.org; Tue, 29 Aug 2023 09:21:12 -0400 Received: by mail-lf1-x12e.google.com with SMTP id 2adb3069b0e04-50098cc8967so6904454e87.1 for ; Tue, 29 Aug 2023 06:21:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1693315267; x=1693920067; 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=pIaXhqvjX6xMFpNg8SHdTT6gdjOJPQH2OOxiQdoGFyE=; b=Q0KYQ+/8lKMhyTX6oKfoJq6/k17gRecXkn7MR9Vl/g+DIrxWpDNWktBM7z3Dv5WdKS aenijnPbjpWH7/0Fuj6yGLEg/dA6EMzfqVr+fE1YJNsMVE4SdJsWvDSqx2diklxR1sKa 2iIH2yBsCPK9O7yz7Wepc3zRO6kg9C5mvblALM0g8pqxc/SLl92wRRaX4wINBouOEP+2 2NDWLjMyaxJTjfWqhffSEFdzk6Kc1HI2qSLfEhvS7qRPftT5pjby7qtnPb+2RFGKnPt/ z9Hm+ZGWuMMHQBqP6cwns+ndNp136YCaLviIj/EMhZ0UVzKkL68XLzMu150u9cNbvJBm o/Tg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693315267; x=1693920067; 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=pIaXhqvjX6xMFpNg8SHdTT6gdjOJPQH2OOxiQdoGFyE=; b=ak9Tyqbmr7bmvOkpQSwmRSFXqOuNt75peSQMbXOePrgFKLREtdqTvMD7lO9Bd6vvBK bYP7Y8DMmRt6VbcmY9OOrMi7SNJM8hQiogLdfPq7b0OlZeaECHMkv7k0tsBdkI37s6dL T76F8ctBwbiZgh2kw1ZK6LW8HRBQApRDHkQEGnQZycOfs+sWd9imxk0FurN6qQRSKd85 UVpf5nXYrwn1fZpiCRDOzJBrs4ToSiJs8WiGrTs4AeE/4CNRgu8CxnThlr3Swz1BTA+s GY1YbHYddc6KWmhkcI6gIxebtH4dg6EPlPwM4DNBKvwUmhQJbj//4KYm22uODcuQcudt aHjg== X-Gm-Message-State: AOJu0Yxnev4JK2NiLG/vyPBA2/UEIu/Ape+JPLRao0qusDESCc/IClPq EjKlDy1F8pv4Z8iFbTlo6Pq0aCadwWsXVRdEKbP5BQ== X-Google-Smtp-Source: AGHT+IH/hrP8Vedz+JJVF83/9cwgXmz2qgarMo6K/vUwlOUiX6bhCoBCe6GWuGMffZoKtyeL16dGsorNRQkCrYcuCo4= X-Received: by 2002:a05:6512:3701:b0:500:b7dc:6c90 with SMTP id z1-20020a056512370100b00500b7dc6c90mr4198064lfr.36.1693315266838; Tue, 29 Aug 2023 06:21:06 -0700 (PDT) MIME-Version: 1.0 References: <20230822095156.39868-1-philmd@linaro.org> In-Reply-To: <20230822095156.39868-1-philmd@linaro.org> From: Peter Maydell Date: Tue, 29 Aug 2023 14:20:56 +0100 Message-ID: Subject: Re: [PATCH] target/arm: Use deposit_z() in BCF opcode To: =?UTF-8?Q?Philippe_Mathieu=2DDaud=C3=A9?= Cc: qemu-devel@nongnu.org, qemu-arm@nongnu.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::12e; envelope-from=peter.maydell@linaro.org; helo=mail-lf1-x12e.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, 22 Aug 2023 at 10:51, Philippe Mathieu-Daud=C3=A9 wrote: > > When clearing a bitfield we don't need to lead the "load" ? > source register. Use deposit_z_i32() with the BFC > opcode to save a load_reg() call. > > Signed-off-by: Philippe Mathieu-Daud=C3=A9 > --- > target/arm/tcg/translate.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/target/arm/tcg/translate.c b/target/arm/tcg/translate.c > index b71ac2d0d5..1a6938d1b3 100644 > --- a/target/arm/tcg/translate.c > +++ b/target/arm/tcg/translate.c > @@ -7255,7 +7255,7 @@ static bool trans_UBFX(DisasContext *s, arg_UBFX *a= ) > static bool trans_BFCI(DisasContext *s, arg_BFCI *a) > { > int msb =3D a->msb, lsb =3D a->lsb; > - TCGv_i32 t_in, t_rd; > + TCGv_i32 t_rd; > int width; > > if (!ENABLE_ARCH_6T2) { > @@ -7268,15 +7268,14 @@ static bool trans_BFCI(DisasContext *s, arg_BFCI = *a) > } > > width =3D msb + 1 - lsb; > + t_rd =3D load_reg(s, a->rd); > if (a->rn =3D=3D 15) { > /* BFC */ > - t_in =3D tcg_constant_i32(0); > + tcg_gen_deposit_z_i32(t_rd, t_rd, lsb, width); > } else { > /* BFI */ > - t_in =3D load_reg(s, a->rn); > + tcg_gen_deposit_i32(t_rd, t_rd, load_reg(s, a->rn), lsb, width); > } > - t_rd =3D load_reg(s, a->rd); > - tcg_gen_deposit_i32(t_rd, t_rd, t_in, lsb, width); > store_reg(s, a->rd, t_rd); > return true; The comment says we are saving a load_reg() call, but the code change doesn't seem to do that. Before the change: * for BFC we call load_reg for rd * for BFI we call load_reg for rn and rd After the change: * for BFC we call load_reg for rd * for BFI we call load_reg for rn and rd So we're not saving any load_reg() calls as far as I can see ? -- PMM