From nobody Sat Nov 23 17:53:27 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=nongnu.org ARC-Seal: i=1; a=rsa-sha256; t=1732153825; cv=none; d=zohomail.com; s=zohoarc; b=RuzrB4lyH51LJ8EPb8kqnbW0PWvYnEyByPsk/OgrpO5w3dYEAO8OPfaCwdynP7IkiVw1YT6f1j3q2Y7hNV7kjv+cz2m/Ei7jxHxSUEpJgyuKWBM08wpqSO+IBuN/cELO1HG1UAkUmFKAFWJrFAZuU6rGqYE42tU4DOR8sW5KPyw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1732153825; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Reply-To:Reply-To:References:Sender:Subject:Subject:To:To:Message-Id; bh=gOqbb409IemoDA9cXRKMqCB6ZUSy0Qk58RmK/jyokAM=; b=J6wifnqvbWUBSmsGt96s0XqoZI2zt6yIg9i22HGWA0qD1n6PWupyOis80eaSKHJbQO/Erjl5g17PY9FzC6L+bgSVyBpemlv7BpKpS2xogxA85HBZq8RJGQDgJVTk8DvDNqqnxXzZoPFpueBdFaxCM4MqAx/l+Z6FeOj7Kao1wMk= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1732153824977156.45141354552425; Wed, 20 Nov 2024 17:50:24 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tDwHx-0001fT-P9; Wed, 20 Nov 2024 20:47:21 -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 1tDwHu-0001dO-MO for qemu-devel@nongnu.org; Wed, 20 Nov 2024 20:47:18 -0500 Received: from rev.ng ([94.130.142.21]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tDwHt-0004ZP-7S for qemu-devel@nongnu.org; Wed, 20 Nov 2024 20:47:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=rev.ng; s=dkim; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive:List-Unsubscribe:List-Unsubscribe-Post: List-Help; bh=gOqbb409IemoDA9cXRKMqCB6ZUSy0Qk58RmK/jyokAM=; b=LQ28/UUF0fF3/ns UMioWfeToFvaoy2MSNVq5FSH6NXASrhNUrNy3f2kiAOfLXOB6pTSB0kroWBFiG9knggN1/iuBQwQ2 S2EGXvo+uYlj6Rac5jrZj9VWFRavn1To83P/d9SFeBmLmeQsZsDwhRL87lWnVDifCI1ygWJ7oXeWj dI=; To: qemu-devel@nongnu.org Cc: ale@rev.ng, ltaylorsimpson@gmail.com, bcain@quicinc.com, richard.henderson@linaro.org, philmd@linaro.org, alex.bennee@linaro.org Subject: [RFC PATCH v1 22/43] helper-to-tcg: PrepareForTcgPass, remove functions w. cycles Date: Thu, 21 Nov 2024 02:49:26 +0100 Message-ID: <20241121014947.18666-23-anjo@rev.ng> In-Reply-To: <20241121014947.18666-1-anjo@rev.ng> References: <20241121014947.18666-1-anjo@rev.ng> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=94.130.142.21; envelope-from=anjo@rev.ng; helo=rev.ng 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_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 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: , Reply-to: Anton Johansson From: Anton Johansson via Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1732153826513116600 Content-Type: text/plain; charset="utf-8" Functions with cycles are removed for two primary reasons: * as a simplifying assumption for register allocation which occurs down the line, and; * if a function contains cycles post-optimization neither unrolling or loop vectorization were beneficial, and the function _might_ be better suited as a helper anyway. Cycles are detected by iterating over Strongly Connected Components (SCCs) which imply the existence of cycles if: - a SCC contains more than one node, or; - it has a self-edge. Signed-off-by: Anton Johansson --- .../PrepareForTcgPass/PrepareForTcgPass.cpp | 32 +++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForT= cgPass.cpp b/subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForT= cgPass.cpp index f0ef1abd17..ccbe3820a0 100644 --- a/subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForTcgPass.= cpp +++ b/subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForTcgPass.= cpp @@ -16,10 +16,42 @@ // =20 #include +#include +#include +#include =20 using namespace llvm; =20 +static void removeFunctionsWithLoops(Module &M, ModuleAnalysisManager &MAM) +{ + // Iterate over all Strongly Connected Components (SCCs), a SCC implies + // the existence of loops if: + // - it has more than one node, or; + // - it has a self-edge. + SmallVector FunctionsToRemove; + for (Function &F : M) { + if (F.isDeclaration()) { + continue; + } + for (auto It =3D scc_begin(&F); !It.isAtEnd(); ++It) { +#if LLVM_VERSION_MAJOR > 10 + if (It.hasCycle()) { +#else + if (It.hasLoop()) { +#endif + FunctionsToRemove.push_back(&F); + break; + } + } + } + + for (auto *F : FunctionsToRemove) { + F->deleteBody(); + } +} + PreservedAnalyses PrepareForTcgPass::run(Module &M, ModuleAnalysisManager = &MAM) { + removeFunctionsWithLoops(M, MAM); return PreservedAnalyses::none(); } --=20 2.45.2