Path: utzoo!attcan!uunet!yale!mfci!colwell From: colwell@mfci.UUCP (Bob Colwell) Newsgroups: comp.arch Subject: Re: RISC machines and scoreboarding Message-ID: <454@m3.mfci.UUCP> Date: 29 Jun 88 02:09:25 GMT References: <1082@nud.UUCP> <2438@winchester.mips.COM> <1098@nud.UUCP> <2465@winchester.mips.COM> <318@mucmot.UUCP> Sender: root@mfci.UUCP Reply-To: colwell@mfci.UUCP (Bob Colwell) Organization: Multiflow Computer Inc., Branford Ct. 06405 Lines: 35 In article <318@mucmot.UUCP> ron@mucmot.UUCP (Ron Voss) writes: >In article <2465@winchester.mips.COM>, mash@mips.COM (John Mashey) writes: >> c) Figuring that a RISC compiler should do optimization, but worrying >> that this feature might be buggy, is like worrying about the safety >> of flying in a 747 and bringing your own seat-belt because you >> don't really trust Boeing to remember to include them :-) > >I have observed a few cases where hours were wasted searching for a >programming bug, only to find that the CISC (68020) compiler's optimizer >is buggy (so one turns on the optimizer only for a release, since it >slows compilations anyway, thoughouly test again after turning on, etc.). > >Are there really *good* reasons to put more trust in RISC optimizers? Ron, I couldn't let that one slide on by. I think it's a truism that good designers produce good designs, including compilers/optimizers, and not-so-good designers produce everything else. My experience has been that the quality of a piece of software is a far stronger function of the abilities of its creators than of its intrinsic complexity. One could perhaps make the case the a RISC optimizer is likely to be intrinsically less complex than its CISC counterpart due to the more-easily-understood machine spec, but it's probably impossible to prove, and I don't think it's as strong an argument as the above. I also have the feeling that more talented designers are turning their attentions to compilers than ever before, so perhaps the overall quality of this kind of software is improving, but I won't even try to defend that thesis if you don't like it. Bob Colwell mfci!colwell@uunet.uucp Multiflow Computer 175 N. Main St. Branford, CT 06405 203-488-6090