Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!news.litech.org!news.lightlink.com!news.iecc.com!.POSTED!nerds-end From: Jean-Marc Bourguet Newsgroups: comp.compilers Subject: Re: Compiler optimization and floating point operations Date: Thu, 24 Oct 2013 15:51:59 +0200 Organization: Guest of ProXad - France Lines: 12 Sender: johnl@iecc.com Approved: comp.compilers@iecc.com Message-ID: <13-10-030@comp.compilers> References: <13-10-026@comp.compilers> <13-10-029@comp.compilers> NNTP-Posting-Host: news.iecc.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: leila.iecc.com 1382627941 89929 64.57.183.58 (24 Oct 2013 15:19:01 GMT) X-Complaints-To: abuse@iecc.com NNTP-Posting-Date: Thu, 24 Oct 2013 15:19:01 +0000 (UTC) Keywords: arithmetic Posted-Date: 24 Oct 2013 11:19:01 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:1013 George Neuner writes: > [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] You forgot about NaN ;-) (but I agree associative was probably intended). Yours, -- Jean-Marc [How are NaNs not commutative? -John]