From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-0016f401.pphosted.com (mx0a-0016f401.pphosted.com [67.231.148.174]) by sourceware.org (Postfix) with ESMTPS id 5A3513858D39 for ; Fri, 19 May 2023 02:14:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 5A3513858D39 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=marvell.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=marvell.com Received: from pps.filterd (m0045849.ppops.net [127.0.0.1]) by mx0a-0016f401.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 34IHoIQK012879 for ; Thu, 18 May 2023 19:14:22 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=marvell.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=pfpt0220; bh=MUHWxZWG8M+zuZ1PMjKF9Je4fxEOYOlqTpgCiLCDejY=; b=dTKSeUHF5llS+LnVsmVdWz7KHUW+bexlevS7qM4m4ezoB8uPIpI32AOEuLU5Qvki7fYn PyAcxVOuy0+X5ZJA434vu0nt58ldxfB5EMX/2AYE5NSFS7g72dWjng9lGCLz3oMrzM8b 5cvQsk3J+0hTH/CkyR91li1yVcMdS/Be0P4ZSPQ5WuVgBmGXaqkOJjxdUIUIRh0eiZmS 7rmV9WMmr2neNRM8KkNnp2XKfrLPb3M5/LAawlN22Vyy99I5SVp2ihZ90/Us9/v4cJLC DSQ8g573Dg8vIoPCaC1PMqeRntW5JI/9Nzh8JQy+H8F/HakREKh/glEXkUW/FUB7a7q1 Pw== Received: from dc5-exch01.marvell.com ([199.233.59.181]) by mx0a-0016f401.pphosted.com (PPS) with ESMTPS id 3qn7jbe58g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Thu, 18 May 2023 19:14:22 -0700 Received: from DC5-EXCH02.marvell.com (10.69.176.39) by DC5-EXCH01.marvell.com (10.69.176.38) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Thu, 18 May 2023 19:14:20 -0700 Received: from maili.marvell.com (10.69.176.80) by DC5-EXCH02.marvell.com (10.69.176.39) with Microsoft SMTP Server id 15.0.1497.48 via Frontend Transport; Thu, 18 May 2023 19:14:20 -0700 Received: from vpnclient.wrightpinski.org.com (unknown [10.69.242.187]) by maili.marvell.com (Postfix) with ESMTP id 0AD903F706F; Thu, 18 May 2023 19:14:18 -0700 (PDT) From: Andrew Pinski To: CC: Andrew Pinski Subject: [PATCH 1/2] Improve do_store_flag for single bit comparison against 0 Date: Thu, 18 May 2023 19:14:09 -0700 Message-ID: <20230519021410.1841811-1-apinski@marvell.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Proofpoint-GUID: 0pxFlMTJ-GibSIeqONj1Hpt6IY-4wf4g X-Proofpoint-ORIG-GUID: 0pxFlMTJ-GibSIeqONj1Hpt6IY-4wf4g X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-05-18_17,2023-05-17_02,2023-02-09_01 X-Spam-Status: No, score=-14.3 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,KAM_NUMSUBJECT,RCVD_IN_DNSWL_LOW,SPF_HELO_NONE,SPF_NONE,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: While working something else, I noticed we could improve the following function code generation: ``` unsigned f(unsigned t) { if (t & ~(1<<30)) __builtin_unreachable(); return t != 0; } ``` Right know we just emit a comparison against 0 instead of just a shift right by 30. There is code in do_store_flag which already optimizes `(t & 1<<30) != 0` to `(t >> 30) & 1`. This patch extends it to handle the case where we know t has a nonzero of just one bit set. OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. gcc/ChangeLog: * expr.cc (do_store_flag): Extend the one bit checking case to handle the case where we don't have an and but rather still one bit is known to be non-zero. --- gcc/expr.cc | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/gcc/expr.cc b/gcc/expr.cc index 5ede094e705..91528e734e7 100644 --- a/gcc/expr.cc +++ b/gcc/expr.cc @@ -13083,15 +13083,30 @@ do_store_flag (sepops ops, rtx target, machine_mode mode) && integer_zerop (arg1) && (TYPE_PRECISION (ops->type) != 1 || TYPE_UNSIGNED (ops->type))) { - gimple *srcstmt = get_def_for_expr (arg0, BIT_AND_EXPR); - if (srcstmt - && integer_pow2p (gimple_assign_rhs2 (srcstmt))) + wide_int nz = tree_nonzero_bits (arg0); + + if (wi::popcount (nz) == 1) { + tree op0; + tree op1; + gimple *srcstmt = get_def_for_expr (arg0, BIT_AND_EXPR); + /* If the defining statement was (x & POW2), then remove the and + as we are going to add it back. */ + if (srcstmt + && integer_pow2p (gimple_assign_rhs2 (srcstmt))) + { + op0 = gimple_assign_rhs1 (srcstmt); + op1 = gimple_assign_rhs2 (srcstmt); + } + else + { + op0 = arg0; + op1 = wide_int_to_tree (TREE_TYPE (op0), nz); + } enum tree_code tcode = code == NE ? NE_EXPR : EQ_EXPR; type = lang_hooks.types.type_for_mode (mode, unsignedp); - tree temp = fold_build2_loc (loc, BIT_AND_EXPR, TREE_TYPE (arg1), - gimple_assign_rhs1 (srcstmt), - gimple_assign_rhs2 (srcstmt)); + tree temp = fold_build2_loc (loc, BIT_AND_EXPR, TREE_TYPE (op0), + op0, op1); temp = fold_single_bit_test (loc, tcode, temp, arg1, type); if (temp) return expand_expr (temp, target, VOIDmode, EXPAND_NORMAL); -- 2.31.1