Path: csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!npeer03.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!border3.nntp.dca.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!news.iecc.com!.POSTED!nerds-end From: Abid Newsgroups: comp.compilers Subject: Compiler optimization and floating point operations Date: Wed, 23 Oct 2013 13:47:10 -0700 (PDT) Organization: Compilers Central Lines: 16 Sender: johnl@iecc.com Approved: comp.compilers@iecc.com Message-ID: <13-10-026@comp.compilers> NNTP-Posting-Host: news.iecc.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 X-Trace: leila.iecc.com 1382576985 82656 64.57.183.58 (24 Oct 2013 01:09:45 GMT) X-Complaints-To: abuse@iecc.com NNTP-Posting-Date: Thu, 24 Oct 2013 01:09:45 +0000 (UTC) Keywords: arithmetic, optimize, question Posted-Date: 23 Oct 2013 21:09:45 EDT X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com X-FAQ-and-archives: http://compilers.iecc.com X-Received-Bytes: 1499 Xref: csiph.com comp.compilers:1009 Hi All: Does back end compiler optimizations affect the floating point accuracy? Is there any research work in this area? Thanks, Abid [The answer to the first question is "sometimes", and there has been a great deal of work in this area going back to the 1960s. I know IBM Fortran compilers that carefully preserve bit identical results in regular and optimized code, and I know other compilers that freely use all of the mathematical (but not arithmetic) equivalences that Fortran allows. -John]