From:	j DOT aldrich6 AT genie DOT com
Message-Id:	<199603250147.AA209418472@relay1.geis.com>
Date:	Mon, 25 Mar 96 01:34:00 UTC 0000
To:	djgpp AT delorie DOT com
Mime-Version:	1.0
Subject:	Re: Optimization causes error

Reply to message 2241407    from BILL_CURRIE AT M on 03/24/96  5:12PM


>> This happens because the -O3 option goes berserk, inlining everything
>> it can. Unfortunately the inline asm does not touch the labels you
>> provide, so if you call your asm routine more than once in your code
>> there is more than one copy of your asm routine in the asm file generated
>> (compile with -S to see it). The solution is to simply write your asm
>> function in a different source file to the one it is used in (maybe
>> asmstuff.cc). In this way the compiler cannot inline your asm (since it
>> ends up in a different .o file) and your problem is solved.

>Alternatively, use local labels, ie

[example deleted]

>use b for backwards references and f for forward references.

If I remember correctly (not being an assembly programmer myself), can't
you just use the 'volatile' keyword with the function that contains the asm to
prevent gcc from optimizing it?  As I recall, 'volatile' tells gcc not
tooptimize
any given code/variable it is used with (in addition to its other uses).

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