Path: csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!feeder.erje.net!us.feeder.erje.net!news.linkpendium.com!news.linkpendium.com!news.iecc.com!.POSTED!nerds-end From: glen herrmannsfeldt Newsgroups: comp.compilers Subject: Re: Compiler optimization and floating point operations Date: Thu, 24 Oct 2013 20:21:21 +0000 (UTC) Organization: Aioe.org NNTP Server Lines: 13 Sender: johnl@iecc.com Approved: comp.compilers@iecc.com Message-ID: <13-10-034@comp.compilers> References: <13-10-026@comp.compilers> <13-10-029@comp.compilers> NNTP-Posting-Host: news.iecc.com X-Trace: leila.iecc.com 1382647598 76507 64.57.183.58 (24 Oct 2013 20:46:38 GMT) X-Complaints-To: abuse@iecc.com NNTP-Posting-Date: Thu, 24 Oct 2013 20:46:38 +0000 (UTC) Keywords: arithmetic, administrivia, comment Posted-Date: 24 Oct 2013 16:46:37 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:1017 (snip, John wrote) > [I think you mean they're not associative. I don't know any > situations where a+b != b+a, but lots where a+(b+c) != (a+b)+c -John] I don't know of any with non-commutative addition, but there were some Cray machines with non-commutative multiply. For many Cray applications, getting a close answer fast is better than the exact answer slow. -- glen [Oh, right. Can we safely assume that arithmetic model is dead? -John]