Re: Unsafe Optimizations (formerly Compiler Design in C...)

harrison@necssd.NEC.COM (Mark Harrison)
Sat, 23 Jun 90 04:19:07 GMT

          From comp.compilers

Related articles
[12 earlier articles]
Re: Unsafe Optimizations (formerly Compiler Design in C...) chip@tct.uucp (1990-06-20)
Re: Unsafe Optimizations (formerly Compiler Design in C...) grunwald@foobar.Colorado.EDU (Dirk Grunwald) (1990-06-20)
Re: Unsafe Optimizations (formerly Compiler Design in C...) marti@inf.ethz.ch (1990-06-21)
Re: Unsafe Optimizations (formerly Compiler Design in C...) pardo@june.cs.washington.edu (1990-06-21)
Re: Unsafe Optimizations (formerly Compiler Design in C...) kend%mrloog.wr.tek.com@RELAY.CS.NET (Ken Dickey) (1990-06-21)
Re: Unsafe Optimizations (formerly Compiler Design in C...) chittamu@dino.cs.umass.edu (1990-06-22)
Re: Unsafe Optimizations (formerly Compiler Design in C...) harrison@necssd.NEC.COM (1990-06-23)
| List of all articles for this month |

Newsgroups: comp.compilers
From: harrison@necssd.NEC.COM (Mark Harrison)
Posted-Date: 22 Jun 90 14:57:19 GMT
Keywords: code, optimize, vector
Organization: NEC America Inc. SSD, Irving, TX
References: <1990Jun12.163959.2593@esegue.segue.boston.ma.us> <1990Jun15.051349.3016@esegue.segue.boston.ma.us>
Date: Sat, 23 Jun 90 04:19:07 GMT



In article <1990Jun15.051349.3016@esegue.segue.boston.ma.us>, pardo@june.cs.washington.edu (David Keppel) writes:


> while (*d++ = *s++)
> ; /* VOID */


> while (d[i] = s[i])
> ++i;


I interviewed at Convex Computers once, and during my coding test they
asked me what approach I would take to optimize my code. I mentioned
converting array references to pointers, and everyone laughed. Their
vectorizing code generator was able to vectorize array references,
but there wasn't much they could do with pointers. I thought it
was interesting that one computer's optimization was another computer's
de-optimization.
--
Mark Harrison harrison@necssd.NEC.COM
(214)518-5050 {necntc, cs.utexas.edu}!necssd!harrison
standard disclaimers apply...


--


Post a followup to this message

Return to the comp.compilers page.
Search the comp.compilers archives again.