Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!feed.news.qwest.net!mpls-nntp-01.inet.qwest.net!216.196.98.143.MISMATCH!border4.nntp.dca.giganews.com!border2.nntp.dca.giganews.com!nntp.giganews.com!news.iecc.com!.POSTED!nerds-end From: Cameron McInally Newsgroups: comp.compilers Subject: Re: Compiler optimization and floating point operations Date: Wed, 23 Oct 2013 22:55:58 -0400 Organization: Compilers Central Lines: 22 Sender: johnl@iecc.com Approved: comp.compilers@iecc.com Message-ID: <13-10-027@comp.compilers> References: <13-10-026@comp.compilers> NNTP-Posting-Host: news.iecc.com X-Trace: leila.iecc.com 1382619315 50995 64.57.183.58 (24 Oct 2013 12:55:15 GMT) X-Complaints-To: abuse@iecc.com NNTP-Posting-Date: Thu, 24 Oct 2013 12:55:15 +0000 (UTC) Keywords: arithmetic, optimize Posted-Date: 24 Oct 2013 08:55:15 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:1010 Hey Abid, On Wed, Oct 23, 2013 at 4:47 PM, Abid wrote: > Does back end compiler optimizations affect the floating point > accuracy? Not all optimizations will affect floating point accuracy, but some may. For example, an optimization that makes use of the associative property or distributive property can have an impact. This is the nature of the limited accuracy in floating point numbers. Another common example is the use of FMA (Fused Multiply Add) instructions. Although, using these instructions will most likely lead to better accuracy, since there is only one rounding error applied to the multiply and the add. > Is there any research work in this area? Yes, tons. Search for "floating point accuracy" and you will be sure to find research going way back. -Cameron