Re: Unsafe Optimizations (WAS: Compiler Design in C How about it?)

moss@cs.umass.edu (Eliot Moss)
Sun, 10 Jun 90 22:05:35 GMT

          From comp.compilers

Related articles
[4 earlier articles]
Re: Unsafe Optimizations (WAS: Compiler Design in C How about it?) pardo@cs.washington.edu (1990-06-05)
Re: Unsafe Optimizations (WAS: Compiler Design in C How about it?) robinson@cs.dal.ca (1990-06-05)
Unsafe Optimizations (WAS: Compiler Design in C How about it?) stewart@sdsu.edu (1990-06-05)
Re: Unsafe Optimizations (WAS: Compiler Design in C How about it?) poser@csli.stanford.edu (1990-06-06)
Re: Unsafe Optimizations (WAS: Compiler Design in C How about it?) larus@primost.cs.wisc.edu (1990-06-07)
Re: Unsafe Optimizations (WAS: Compiler Design in C How about it?) tli@%phakt.usc.edu (1990-06-07)
Re: Unsafe Optimizations (WAS: Compiler Design in C How about it?) moss@cs.umass.edu (1990-06-10)
Re: Unsafe Optimizations (WAS: Compiler Design in C How about it?) cwitty@csli.Stanford.EDU (1990-06-14)
Re: Unsafe Optimizations (WAS: Compiler Design in C How about it?) moss@cs.umass.edu (1990-06-14)
Re: Unsafe Optimizations (WAS: Compiler Design in C How about it?) pardo@june.cs.washington.edu (1990-06-15)
| List of all articles for this month |

Newsgroups: comp.compilers
From: moss@cs.umass.edu (Eliot Moss)
References: <1990Jun1.194941.5781@esegue.segue.boston.ma.us> <1990Jun4.212226.18389@esegue.segue.boston.ma.us> <1990Jun7.010349.2097@esegue.segue.boston.ma.us> <1990Jun7.190315.4578@esegue.segue.boston.ma.us>
Date: Sun, 10 Jun 90 22:05:35 GMT
Organization: Dept of Comp and Info Sci, Univ of Mass (Amherst)
Keywords: optimize
In-Reply-To: tli@%phakt.usc.edu's message of 7 Jun 90 19:03:15 GMT

I would like to note that a number of languages are standardized such that
order of evaluation of certain items is *not specified*, and it is legal for
the compiler to choose any order it likes, non-associativity, etc.,
notwithstanding. Frequently optimizers "assume associativity" under this
rubric. If the programmer has a program where she cares about the difference,
then it is up to her to force evaluation order somehow. (I'm not saying I
agree or disagree with this; I'm merely stating it as a fact of life ...)
--


J. Eliot B. Moss, Assistant Professor
Department of Computer and Information Science
Lederle Graduate Research Center
University of Massachusetts
Amherst, MA 01003
(413) 545-4206; Moss@cs.umass.edu
[Indeed, such ambiguity is more the rule than the exception. Fortran and C
are both standardized that way. -John]
--


Post a followup to this message

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