From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,d901a50a5adfec3c X-Google-Attributes: gid103376,public X-Google-Thread: 1094ba,9f0bf354542633fd X-Google-Attributes: gid1094ba,public From: "Dean F. Sutherland" Subject: Re: Fortran or Ada? Date: 1998/09/29 Message-ID: <3610F2E5.A3A507BF@cs.cmu.edu>#1/1 X-Deja-AN: 395997318 Content-Transfer-Encoding: 7bit References: <36068E73.F0398C54@meca.polymtl.ca> <6u8r5o$aa4$1@nnrp1.dejanews.com> <360A3446.8AD84137@lmco.com> <6udre0$ha1$1@nnrp1.dejanews.com> <19980925.185359.250@yktvmv.watson.ibm.com> <6uifdr$dog$1@nnrp1.dejanews.com> <19980928.184428.604@yktvmv.watson.ibm.com> To: jbs@.watson.ibm.com Content-Type: text/plain; charset=us-ascii Organization: Carnegie Mellon Univ. -- Computer Science Dept. Mime-Version: 1.0 Newsgroups: comp.lang.fortran,comp.lang.ada Date: 1998-09-29T00:00:00+00:00 List-Id: jbs@yktvmv.watson.ibm.com wrote: > > > It appears to me that this implicates Ada in at least > two respects: > 1. It appears the developers were having trouble meeting their > performance target tempting them to cut corners. Ada is of course > notoriously inefficient. > 2. It appears there is no cheap way of turning off conversion > error checking in Ada, tempting programmers to leave it active in > inappropriate places. > James B. Shearer Wrong on both counts. For number one, check out http://www.adahome.com/Ammo/Stories/Tartan-Realtime.html This (admittedly old) writeup describes compiled Ada beating both custom hand-written assembly and also C. In my time at Tartan I saw a number of commercial customers (no Gov't mandate!) switch to Tartan Ada for the C3x/C4x DSPs because we were able to produce substantially faster code than TI's C compiler. Speaking as a compiler optimizer writer, Ada's semantics give much more scope for optimization than C (or C++) -- without requiring the level of hairy pointer aliasing analysis that C/C++ compilers must perform to get good results. Ada may be "notoriously inefficient," but there is ABSOLUTELY NOTHING inherent in the language that makes it so. There certainly have been, and will continue to be, Ada compilers with quite impressive and state-of-the-art optimization. Those compilers produce code that is most assuredly competitive with any other language. That "notoriously inefficient" impression is just plain dead wrong. For #2: There's pragma suppress -- thoroughly standard (just look in the reference manual: section 11.5). There are compile time switches. Perhaps it would be wise to consider a more careful fact-check before posting on this subject again. Sincerely, Dean F. Sutherland dsutherland@acm.org dfsuther@cs.cmu.edu ex-Tartan/TI optimization and code generation