Path: csiph.com!goblin3!goblin.stu.neva.ru!news.misty.com!news.iecc.com!.POSTED.news.iecc.com!nerds-end From: "Robin Vowels" Newsgroups: comp.compilers Subject: Re: Optimization techniques and undefined behavior Date: Tue, 7 May 2019 01:22:50 +1000 Organization: Compilers Central Lines: 15 Sender: news@iecc.com Approved: comp.compilers@iecc.com Message-ID: <19-05-041@comp.compilers> References: <19-05-014@comp.compilers> <19-04-021@comp.compilers> <19-04-023@comp.compilers> <19-04-037@comp.compilers> <19-04-039@comp.compilers> <19-04-042@comp.compilers> <19-04-044@comp.compilers> <19-04-047@comp.compilers> <19-05-004@comp.compilers> <19-05-008@comp.compilers> <19-05-014@comp.compilers> <19-05-021@comp.compilers> Mime-Version: 1.0 Content-Type: text/plain; format=flowed; charset="utf-8"; reply-type=response Content-Transfer-Encoding: 8bit Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="82455"; mail-complaints-to="abuse@iecc.com" Keywords: errors, comment Posted-Date: 06 May 2019 13:39:47 EDT X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com X-FAQ-and-archives: http://compilers.iecc.com Xref: csiph.com comp.compilers:2276 From: "David Brown" Sent: Saturday, May 04, 2019 1:23 AM > You are, as usual, very keen to pick out gcc as though it was something > special here. Compilers have been assuming signed integer overflow > never happens for over 20 years (that's just from my own personal > experience), long before gcc was that smart. Some compilers might, but I have not met one that does ignore overflow. Even in evaluating compile-time expressions, an overflow is treated as an error, and a diagnostic is issued. [clang and gcc definitely generate code that ignores integer overflows at runtime. I just checked. -John]