Path: csiph.com!xmission!news.snarked.org!border2.nntp.dca1.giganews.com!nntp.giganews.com!news.iecc.com!.POSTED.news.iecc.com!nerds-end From: Hans Aberg Newsgroups: comp.compilers Subject: Re: Optimization techniques Date: Fri, 19 Apr 2019 00:52:54 +0200 Organization: A noiseless patient Spider Lines: 7 Sender: news@iecc.com Approved: comp.compilers@iecc.com Message-ID: <19-04-008@comp.compilers> References: <19-04-004@comp.compilers> <19-04-006@comp.compilers> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="97510"; mail-complaints-to="abuse@iecc.com" Keywords: optimize, LLVM Posted-Date: 19 Apr 2019 10:34:27 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:2192 On 2019-04-18 10:07, John Levine wrote: > [Great reading list, thanks. Floating add and multiply commute but > they don't associate. a+b should be the sams as b+a, but (a+b)+c not > the same as a+(b+c). -John] Actually, LLVM has an optimization assuming associativity, which is legit with sufficiently high precision.