From patchwork Fri Nov 5 18:17:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Wakely X-Patchwork-Id: 47130 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id DBFB03858432 for ; Fri, 5 Nov 2021 18:19:14 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org DBFB03858432 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1636136354; bh=zrSBQlFyYSZBCmNUH1FwB3x9GJPDXp87cW9ZBJJ1Isg=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=u1m7+fyQBV8mCo9IEqtqClCR8A2xkCGYB2XxZ/rCUiOrG3FCEc/xmix6vaSP8MMaU RHI1tRLhSgT99iQuBUs+EOX59Ih4h8mRpq86ZqiQOGqJs0ETtM9dSO+ZAPs/xZO0Vk vbmbsgVHKs4Fxuft+YroSV3ddfSgEIj8XUmN+mco= X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id A27D53858432 for ; Fri, 5 Nov 2021 18:17:43 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org A27D53858432 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-130-CBK1yZlXM-6U9fHFN7c6jQ-1; Fri, 05 Nov 2021 14:17:42 -0400 X-MC-Unique: CBK1yZlXM-6U9fHFN7c6jQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 37A0310A8E11; Fri, 5 Nov 2021 18:17:41 +0000 (UTC) Received: from localhost (unknown [10.33.36.17]) by smtp.corp.redhat.com (Postfix) with ESMTP id C8E0B60BF1; Fri, 5 Nov 2021 18:17:40 +0000 (UTC) To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [committed] libstdc++: Add [[unlikely]] attributes to std::random_device routines Date: Fri, 5 Nov 2021 18:17:39 +0000 Message-Id: <20211105181739.2245825-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-14.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Jonathan Wakely via Gcc-patches From: Jonathan Wakely Reply-To: Jonathan Wakely Errors-To: gcc-patches-bounces+patchwork=sourceware.org@gcc.gnu.org Sender: "Gcc-patches" Tested x86+64-linux, pushed to trunk. libstdc++-v3/ChangeLog: * src/c++11/random.cc (__x86_rdrand, __x86_rdseed): Add [[unlikely]] attribute. --- libstdc++-v3/src/c++11/random.cc | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/src/c++11/random.cc b/libstdc++-v3/src/c++11/random.cc index 55a73c51fca..4b88818646f 100644 --- a/libstdc++-v3/src/c++11/random.cc +++ b/libstdc++-v3/src/c++11/random.cc @@ -97,7 +97,7 @@ namespace std _GLIBCXX_VISIBILITY(default) unsigned int retries = 100; unsigned int val; - while (__builtin_ia32_rdrand32_step(&val) == 0) + while (__builtin_ia32_rdrand32_step(&val) == 0) [[__unlikely__]] if (--retries == 0) std::__throw_runtime_error(__N("random_device: rdrand failed")); @@ -113,7 +113,7 @@ namespace std _GLIBCXX_VISIBILITY(default) unsigned int retries = 100; unsigned int val; - while (__builtin_ia32_rdseed_si_step(&val) == 0) + while (__builtin_ia32_rdseed_si_step(&val) == 0) [[__unlikely__]] { if (--retries == 0) {