From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 9300B38515D9 for ; Fri, 26 Aug 2022 15:46:14 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 9300B38515D9 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1661528774; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=pIU3bIkwakiAnsGmQIOzm5eGtldqLV+zmgxbQDLTF2o=; b=NlN4Xhs0mHXlpkBBrO1IMnGdOcFgwWBdlh/34s92Sxmq4+fFNTvrYteQQdUSp6KT9XAVBd shszCQbEhfQbBS3Dyx93OMWNvUf2g4CWM0vdtWjOdeRXwuZo3RTOHpkklWx/cBKuZ7NyI+ PbMo09kqzvbgPa5kcVw581PalJIBmJU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-277-PoxYMMGGOMaAx15frkSNHA-1; Fri, 26 Aug 2022 11:46:13 -0400 X-MC-Unique: PoxYMMGGOMaAx15frkSNHA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B5782185A794 for ; Fri, 26 Aug 2022 15:46:12 +0000 (UTC) Received: from abulafia.home (unknown [10.39.193.54]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 67383C15BB3; Fri, 26 Aug 2022 15:46:12 +0000 (UTC) Received: from abulafia.home (localhost [127.0.0.1]) by abulafia.home (8.17.1/8.17.1) with ESMTPS id 27QFk9PX1155995 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Fri, 26 Aug 2022 17:46:09 +0200 Received: (from aldyh@localhost) by abulafia.home (8.17.1/8.17.1/Submit) id 27QFk9DZ1155994; Fri, 26 Aug 2022 17:46:09 +0200 From: Aldy Hernandez To: GCC patches Cc: Jakub Jelinek , Andrew MacLeod , Aldy Hernandez Subject: [PATCH] [ranger] x == -0.0 does not mean we can replace x with -0.0 Date: Fri, 26 Aug 2022 17:46:06 +0200 Message-Id: <20220826154606.1155977-1-aldyh@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII"; x-default=true X-Spam-Status: No, score=-11.5 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,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: On the true side of x == -0.0, we can't just blindly value propagate the -0.0 into every use of x because x could be +0.0 (or vice versa). With this change, we only allow the transformation if !HONOR_SIGNED_ZEROS or if the range is known not to contain 0. Will commit after tests complete. gcc/ChangeLog: * range-op-float.cc (foperator_equal::op1_range): Do not blindly copy op2 range when honoring signed zeros. --- gcc/range-op-float.cc | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc index ad2fae578d2..ff9fe312acf 100644 --- a/gcc/range-op-float.cc +++ b/gcc/range-op-float.cc @@ -252,8 +252,21 @@ foperator_equal::op1_range (frange &r, tree type, switch (get_bool_state (r, lhs, type)) { case BRS_TRUE: - // If it's true, the result is the same as OP2. - r = op2; + if (HONOR_SIGNED_ZEROS (type) + && op2.contains_p (build_zero_cst (type))) + { + // With signed zeros, x == -0.0 does not mean we can replace + // x with -0.0, because x may be either +0.0 or -0.0. + r.set_varying (type); + } + else + { + // If it's true, the result is the same as OP2. + // + // If the range does not actually contain zeros, this should + // always be OK. + r = op2; + } // The TRUE side of op1 == op2 implies op1 is !NAN. r.set_nan (fp_prop::NO); break; -- 2.37.1