Path: utzoo!attcan!uunet!mcvax!hp4nl!philmds!leo
From: leo@philmds.UUCP (Leo de Wit)
Newsgroups: comp.lang.c
Subject: Re: C optimizer
Keywords: C Ultrix
Message-ID: <954@philmds.UUCP>
Date: 14 Feb 89 09:22:17 GMT
References: <515@larry.UUCP>
Reply-To: leo@philmds.UUCP (Leo de Wit)
Organization: Philips I&E DTS Eindhoven
Lines: 15

In article <515@larry.UUCP> jwp@larry.UUCP (Jeffrey W Percival) writes:
|I have a question about how much optimizing I should worry about when
|writing programs in C.  Suppose I have this code fragment:
|
|	x = (1 + cos(r)) / (cos(r) * sin(r));
|	y = (cos(r) - sin(r)) / (1 + sin(r));
|
|I made this up, but the point is the re-use of the sin() and cos()
|calls.  Now, can I expect the compiler to form only one call to sin and
|cos?

Try rand() instead of sin(), cos(). Now, you wouldn't want the compiler
to form only one call to rand(), would you?

    Leo.