From patchwork Wed Feb 28 11:06:26 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 13575200 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 2B3BEC47DD9 for ; Wed, 28 Feb 2024 11:07:21 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rfHll-0002DG-T0; Wed, 28 Feb 2024 06:06:38 -0500 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 1rfHlj-0002Cx-RE for qemu-devel@nongnu.org; Wed, 28 Feb 2024 06:06:36 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rfHlh-0008Ud-NJ for qemu-devel@nongnu.org; Wed, 28 Feb 2024 06:06:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1709118391; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=EIxQVyU6go+0CROhf2rdWnGTMgB9SOkWFl2adckGTt8=; b=R/i1WC1aCrhoBDQjlw709ip5kyzQm2F2bM4akzNeuw5iawmKhwhpSULIX8Er6k0M1tQ2Bm n+dhFlWPoN4REvQZBhz776BxAIFpOb60RL4ZGe/mFDdqsgj3uw++LHm4M5o7J4exHa5llF EUuWG0NX1L08GuXUDrEQgxang7LwFF4= Received: from mail-ej1-f71.google.com (mail-ej1-f71.google.com [209.85.218.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-411-qS86PA65NAehtZJ37SrO5Q-1; Wed, 28 Feb 2024 06:06:30 -0500 X-MC-Unique: qS86PA65NAehtZJ37SrO5Q-1 Received: by mail-ej1-f71.google.com with SMTP id a640c23a62f3a-a43381a778aso234065266b.1 for ; Wed, 28 Feb 2024 03:06:30 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709118389; x=1709723189; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=EIxQVyU6go+0CROhf2rdWnGTMgB9SOkWFl2adckGTt8=; b=Z7PnijuG5yvhY1WqxMzbI9mwIwAwViPH6dQJ7beeYmlQ92rixsdn81kxqEqqnskVhl 1hT86zaep8JC/Ho7WJ5X47bd2iMy/36lrboBsh/YkS55Tvl+XpohcQpkGXrFNksbfE7s W/X4s3XDqlFkFSjAsONqSBF8Ktp67XBOfTXbLy2uIdz1gC0Nl1duzJcPNnx/0ylHyFfH M8eDevkuQ+uDl4UdPT9b8krgdCkm/9F/W466GyJxYhgerod9H5iztfOHTuvBpmBSGhGA nY7qk6wOVEWIqpxVZO1LOzWMFVwjjOGEUs0pepLLtADZnIQt8wSxM9ig/DT4g5DwAnGr xatw== X-Gm-Message-State: AOJu0YzFgIE5fQMcNwO5TyK1OCoFzHhnZ/uznrn4heuerf9VpKLZddB2 Jz4bNThBMI3a+r+/XjGLLoKm/vcGpTnEiLf3G0GGPba3e5SAGis0TvJLpi/axBpU8UDdjnUdLLx w7tGnf691TEiXa9QSZdhz0zB0cpPDN5af8XKedxb1vW2IuYtHgOf6ct/63r2klqp5//VmnR6o+W Vc73lerUzRaAlgFF6hqUKUVZW9KJsgGB3iUqjg X-Received: by 2002:a17:906:ad5:b0:a44:da2:11b6 with SMTP id z21-20020a1709060ad500b00a440da211b6mr601622ejf.67.1709118388920; Wed, 28 Feb 2024 03:06:28 -0800 (PST) X-Google-Smtp-Source: AGHT+IEpBWxXpzP8EEJCHrLUIRTgRRnQlyjxGy8yr6eghDCHdIjd8Cxj7liIrqkv2tuu0mYXKoQIVQ== X-Received: by 2002:a17:906:ad5:b0:a44:da2:11b6 with SMTP id z21-20020a1709060ad500b00a440da211b6mr601608ejf.67.1709118388451; Wed, 28 Feb 2024 03:06:28 -0800 (PST) Received: from [192.168.10.118] ([2001:b07:6468:f312:63a7:c72e:ea0e:6045]) by smtp.gmail.com with ESMTPSA id ti6-20020a170907c20600b00a43c3e5e008sm1281286ejc.205.2024.02.28.03.06.27 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Feb 2024 03:06:27 -0800 (PST) From: Paolo Bonzini To: qemu-devel@nongnu.org Subject: [PATCH] tcg/optimize: lower some ANDs to two shifts Date: Wed, 28 Feb 2024 12:06:26 +0100 Message-ID: <20240228110626.287178-1-pbonzini@redhat.com> X-Mailer: git-send-email 2.43.2 MIME-Version: 1.0 Received-SPF: pass client-ip=170.10.129.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.088, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham 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 Signed-off-by: Paolo Bonzini --- tcg/optimize.c | 60 +++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 52 insertions(+), 8 deletions(-) diff --git a/tcg/optimize.c b/tcg/optimize.c index 3995bc047db..8ea1f287788 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -1281,6 +1281,43 @@ static bool fold_add2(OptContext *ctx, TCGOp *op) return fold_addsub2(ctx, op, true); } +static bool fold_and_to_shifts(OptContext *ctx, uint64_t c, TCGOp *op) +{ + TCGOpcode shl_opc = tcg->type == TCG_TYPE_I32 ? INDEX_op_shl_i32 : INDEX_op_shl_i64; + TCGOpcode shr_opc = tcg->type == TCG_TYPE_I32 ? INDEX_op_shr_i32 : INDEX_op_shr_i64; + + TCGOpcode first, second; + int count; + TCGOp *op2; + + unsigned_c = tcg->type == TCG_TYPE_I32 ? (uint32_t) c : c; + if (is_power_of_2(-c) && + !tcg_op_imm_match(op->opc, c)) { + /* AND with 11...11000, shift right then left. */ + count = ctz64(c); + first = shr_opc; + } else if (is_power_of_2(c + 1) && + !tcg_op_imm_match(INDEX_op_and_i64, c)) { + /* AND with 00...00111, shift left then right. */ + int bits = tcg->type == TCG_TYPE_I32 ? 32 : 64; + count = bits - cto64(c); + first = shl_opc; + } else { + return false; + } + + + op->opc = first; + op->args[2] = arg_new_constant(ctx, count); + + second = shl_opc ^ shr_opc ^ first; + op2 = tcg_op_insert_after(ctx->tcg, op, second, 3); + op2->args[0] = op->args[0]; + op2->args[1] = op->args[0]; + op2->args[2] = arg_new_constant(ctx, count); + return true; +} + static bool fold_and(OptContext *ctx, TCGOp *op) { uint64_t z1, z2; @@ -1294,6 +1331,18 @@ static bool fold_and(OptContext *ctx, TCGOp *op) z1 = arg_info(op->args[1])->z_mask; z2 = arg_info(op->args[2])->z_mask; + + /* + * Known-zeros does not imply known-ones. Therefore unless + * arg2 is constant, we can't infer affected bits from it. + */ + if (arg_is_const(op->args[2])) { + if (fold_and_to_shifts(ctx, z2, op)) { + return true; + } + ctx->a_mask = z1 & ~z2; + } + ctx->z_mask = z1 & z2; /* @@ -1303,14 +1352,6 @@ static bool fold_and(OptContext *ctx, TCGOp *op) ctx->s_mask = arg_info(op->args[1])->s_mask & arg_info(op->args[2])->s_mask; - /* - * Known-zeros does not imply known-ones. Therefore unless - * arg2 is constant, we can't infer affected bits from it. - */ - if (arg_is_const(op->args[2])) { - ctx->a_mask = z1 & ~z2; - } - return fold_masks(ctx, op); } @@ -1333,6 +1374,9 @@ static bool fold_andc(OptContext *ctx, TCGOp *op) */ if (arg_is_const(op->args[2])) { uint64_t z2 = ~arg_info(op->args[2])->z_mask; + if (fold_and_to_shifts(ctx, z2, op)) { + return true; + } ctx->a_mask = z1 & ~z2; z1 &= z2; }