Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!lotus!esegue!compilers-sender
From: soi!alex@husc6.harvard.edu (Alex Zatsman)
Newsgroups: comp.compilers
Subject: Re: Automatic optimizations (profile-feedback)
Message-ID: <1989Dec17.231054.481@esegue.segue.boston.ma.us>
Date: 17 Dec 89 23:10:54 GMT
References: <1989Dec13.175606.27677@esegue.segue.boston.ma.us>
Sender: compilers-sender@esegue.segue.boston.ma.us
Reply-To: soi!alex@husc6.harvard.edu (Alex Zatsman)
Organization: Software Options Inc.,  Cambridge,  Mass.
Lines: 24
Approved: compilers@esegue.segue.boston.ma.us

Here in Software Options we've built a so called CGBC back end (CGBC
stands for Code Generation By Coagulation). The technique was
originally developed by Mike Karr in his Ph.D. thesis.  (see his
article in 1984 Proceedings of the SIGPLAN Symposium on Compiler
Construction).  The back end expected as an input a flow graph with
frequencies for each arc.

Being only a prototype, the back end did not use any of the classical
optimization like strength reduction and loop invariants. Nevertheless
the code it produced was no worse and usually better than optimizing C
compilers for Unix (we compared it with Sun and Ultrix C compilers).
It should work much better than that once we have standard
optimization parts added to it, which is expected to be during next
year.

Alex Zatsman.
Software Options, Inc.
22 Hilliard St.
Cambridge MA, 02138
(617) 497-5054
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