From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gtd-gmbh.de (mail.gtd.eu [46.24.46.35]) by sourceware.org (Postfix) with ESMTPS id 6F8373871026 for ; Tue, 10 Mar 2020 10:25:03 +0000 (GMT) X-MDAV-Result: clean X-MDAV-Processed: gtd-gmbh.de, Tue, 10 Mar 2020 11:24:19 +0100 Received: from localhost.localdomain [(46.237.211.46)] by gtd-gmbh.de (MDaemon PRO v19.5.4) with ESMTPA id md50013567928.msg; Tue, 10 Mar 2020 11:24:18 +0100 X-Spam-Processed: gtd-gmbh.de, Tue, 10 Mar 2020 11:24:18 +0100 (not processed: message from trusted or authenticated source) X-MDRemoteIP: 46.237.211.46 X-MDHelo: localhost.localdomain X-MDArrival-Date: Tue, 10 Mar 2020 11:24:18 +0100 X-Authenticated-Sender: fabian.schriever@gtd-gmbh.de X-Return-Path: prvs=1338053b71=fabian.schriever@gtd-gmbh.de X-Envelope-From: fabian.schriever@gtd-gmbh.de X-MDaemon-Deliver-To: newlib@sourceware.org From: Fabian Schriever To: newlib@sourceware.org Cc: Fabian Schriever Subject: [PATCH] Fix error in fdim/f for infinities Date: Tue, 10 Mar 2020 11:24:12 +0100 Message-Id: <20200310102412.391-1-fabian.schriever@gtd-gmbh.de> X-Mailer: git-send-email 2.24.1.windows.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-26.9 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_NONE, UNPARSEABLE_RELAY autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: newlib@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Newlib mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 Mar 2020 10:25:17 -0000 The comparison c == FP_INFINITE causes the function to return +inf as it expects x = +inf to always be larger than y. This shortcut causes several issues as it also returns +inf for the following cases: - fdim(+inf, +inf), expected (as per C99): +0.0 - fdim(-inf, any non NaN), expected: +0.0 I don't see a reason to keep the comparison as all the infinity cases return the correct result using just the ternary operation. --- newlib/libm/common/s_fdim.c | 5 +---- newlib/libm/common/sf_fdim.c | 5 +---- 2 files changed, 2 insertions(+), 8 deletions(-) diff --git a/newlib/libm/common/s_fdim.c b/newlib/libm/common/s_fdim.c index 73a027953..61a4908f3 100644 --- a/newlib/libm/common/s_fdim.c +++ b/newlib/libm/common/s_fdim.c @@ -49,11 +49,8 @@ ANSI C, POSIX. double y; #endif { - int c = __fpclassifyd(x); - if (c == FP_NAN) return(x); + if (__fpclassifyd(x) == FP_NAN) return(x); if (__fpclassifyd(y) == FP_NAN) return(y); - if (c == FP_INFINITE) - return HUGE_VAL; return x > y ? x - y : 0.0; } diff --git a/newlib/libm/common/sf_fdim.c b/newlib/libm/common/sf_fdim.c index fe349098b..8fee57002 100644 --- a/newlib/libm/common/sf_fdim.c +++ b/newlib/libm/common/sf_fdim.c @@ -14,11 +14,8 @@ float y; #endif { - int c = __fpclassifyf(x); - if (c == FP_NAN) return(x); + if (__fpclassifyf(x) == FP_NAN) return(x); if (__fpclassifyf(y) == FP_NAN) return(y); - if (c == FP_INFINITE) - return HUGE_VALF; return x > y ? x - y : 0.0; } -- 2.24.1.windows.2