Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!ames!amdahl!rtech!gonzo!daveb
From: daveb@gonzo.UUCP (Dave Brower)
Newsgroups: comp.lang.c
Subject: Re: Ambiguous C?
Message-ID: <630@gonzo.UUCP>
Date: 29 Apr 89 18:09:12 GMT
References: <111@ssp1.idca.tds.philips.nl> <9249@alice.UUCP>
Reply-To: daveb@gonzo.UUCP (Dave Brower)
Organization: Gonzo Media Group
Lines: 22

In article <9249@alice.UUCP> ark@alice.UUCP (Andrew Koenig) suggests:
>To suppress the optimization, you can probably conceal the
>value of SCU_BDID from the compiler by using it in a way that
>the compiler thinks might change.  For instance:
>
>	static int SCU_BDID = 0x2000;
>
>Now the compiler probably won't be smart enough to realize that
                  ^^^^^^^^
>SCU_BDID is really a constant, so it will have to generate code
>that caters to any bit in the whole word being on.

Since it is static, the compiler might be able to figure it out.  

To get a higher degree of confidence, you can remove the static, showing
the compiler that some other file might know about the variable and
change it.

-dB
-- 
"An expert is someone who's right 75% of the time"
{sun,mtxinu,amdahl,hoptoad}!rtech!gonzo!daveb	daveb@gonzo.uucp