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=-0.7 required=5.0 tests=BAYES_00,HEADER_SPAM, INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: ff499,32898cca6ca4143e X-Google-Attributes: gidff499,public X-Google-Thread: 103376,32898cca6ca4143e X-Google-Attributes: gid103376,public From: jfc@mit.edu (John F Carr) Subject: Re: Compiler Optimisation? Date: 1998/12/13 Message-ID: <98-12-030@comp.compilers>#1/1 X-Deja-AN: 421868147 Sender: johnl@iecc.com References: <98-12-010@comp.compilers> <98-12-020@comp.compilers> X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com Organization: Massachvsetts Institvte of Technology Keywords: optimize Newsgroups: comp.lang.ada,comp.compilers X-FAQ-and-archives: http://www.iecc.com/compilers Date: 1998-12-13T00:00:00+00:00 List-Id: Thomas W. Christopher wrote: >As I recall, he found that "folding," performing constant arithmetic at >compile time, not only makes the compiled code run faster, but also the >compiler. On AIX 3.1, I found that "gcc -O -c" was often faster than "gcc -c" because the assembler was so slow. Apparently IBM didn't use it much internally (or adb, the assembly-level debugger which was also slow and buggy). It was faster for gcc to optimize the code than it was for as to process the extra instructions in unoptimized code. -- John Carr (jfc@mit.edu)