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[2001:8b0:bf73:93f7::51bb:e332]) by smtp.gmail.com with ESMTPSA id n2-20020adfe342000000b00343eac2acc4sm30378243wrj.111.2024.04.29.13.29.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Apr 2024 13:29:17 -0700 (PDT) Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.95) (envelope-from ) id 1s1Xbz-003Mos-1r; Mon, 29 Apr 2024 20:28:31 +0000 Date: Mon, 29 Apr 2024 20:28:31 +0000 (UTC) From: Joseph Myers To: Krishna Narayanan cc: gcc@gcc.gnu.org Subject: Re: [RISC-V] Support for trapping math in RISC-V In-Reply-To: Message-ID: <465937-78a-b98c-14fa-f27a12d83894@redhat.com> References: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII X-Spam-Status: No, score=-3.8 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP 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 Wed, 24 Apr 2024, Krishna Narayanan via Gcc wrote: > Hi all, > Is the RISC-V community planning to add support for trapping math in RISC-V > in the near future!? > This LLVM thread > https://discourse.llvm.org/t/trapping-math-for-risc-v/72168/7 suggests a > software emulation of traps, is the GNU team also on similar lines to this > implementation or has some different views. That strategy sounds both very slow and not even complete (it doesn't cover the case of exact underflow, which doesn't raise the exception flag, but should signal the exception when trapping is enabled). Traps are not part of standard C. I'm not aware of any implementations of the TS 18661-5 interfaces to alternate exception handling either. -- Joseph S. Myers josmyers@redhat.com