From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mengyan1223.wang (mengyan1223.wang [89.208.246.23]) by sourceware.org (Postfix) with ESMTPS id C1F863858D28 for ; Sun, 30 Jan 2022 18:39:18 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C1F863858D28 Received: from [IPv6:240e:358:115e:4e00:dc73:854d:832e:3] (unknown [IPv6:240e:358:115e:4e00:dc73:854d:832e:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-384) server-digest SHA384) (Client did not present a certificate) (Authenticated sender: xry111@mengyan1223.wang) by mengyan1223.wang (Postfix) with ESMTPSA id 411FB65B17 for ; Sun, 30 Jan 2022 13:39:15 -0500 (EST) Message-ID: <8b49a9906a0d1019bd877bf526f71ab5321550fe.camel@mengyan1223.wang> Subject: [PATCH] fold-const: do not fold 'inf/inf' with -ftrapping-math [PR95115] From: Xi Ruoyao To: gcc-patches@gcc.gnu.org Date: Mon, 31 Jan 2022 02:39:09 +0800 Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.42.3 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-3039.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, JMQ_SPF_NEUTRAL, SPF_HELO_PASS, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE 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-List-Received-Date: Sun, 30 Jan 2022 18:39:20 -0000 'inf/inf' should raise an invalid operation exception at runtime. So it should not be folded during compilation unless -fno-trapping-math is used. gcc/ PR middle-end/95115 * fold-const.cc (const_binop): Do not fold "inf/inf". gcc/testsuite * gcc.dg/pr95115.c: New test. --- gcc/fold-const.cc | 8 ++++++++ gcc/testsuite/gcc.dg/pr95115.c | 25 +++++++++++++++++++++++++ 2 files changed, 33 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/pr95115.c diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc index fd9c6352d4f..0e99d5a2e3d 100644 --- a/gcc/fold-const.cc +++ b/gcc/fold-const.cc @@ -1283,6 +1283,14 @@ const_binop (enum tree_code code, tree arg1, tree arg2) && (flag_trapping_math || ! MODE_HAS_INFINITIES (mode))) return NULL_TREE; + /* Don't perform "inf/inf", because it would raise an invalid + operation exception (IEEE 754 section 7.2 clause d). */ + if (code == RDIV_EXPR + && flag_trapping_math + && REAL_VALUE_ISINF (d1) + && REAL_VALUE_ISINF (d2)) + return NULL_TREE; + /* If either operand is a NaN, just return it. Otherwise, set up for floating-point trap; we return an overflow. */ if (REAL_VALUE_ISNAN (d1)) diff --git a/gcc/testsuite/gcc.dg/pr95115.c b/gcc/testsuite/gcc.dg/pr95115.c new file mode 100644 index 00000000000..46a95dfb698 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr95115.c @@ -0,0 +1,25 @@ +/* { dg-do run } */ +/* { dg-options "-O2 -ftrapping-math" } */ +/* { dg-add-options ieee } */ +/* { dg-require-effective-target fenv_exceptions } */ + +#include +#include + +double +x (void) +{ + double d = __builtin_inf (); + return d / d; +} + +int +main (void) +{ + double r = x (); + if (!__builtin_isnan (r)) + abort (); + if (!fetestexcept (FE_INVALID)) + abort (); + exit (0); +} -- 2.35.1