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2001 Dec 30 17:09

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Re: [vox-tech] C/ASM question
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Re: [vox-tech] C/ASM question

You should be able to do 
-fno-schedule-insns and -fno-schedule-insns2

to turn the scheduler off.  You can verify by doing 

This will tell you when something is reordered.

As a note, these optimizations above all are supposed to maintain program
integrity.  Meaning they shouldn't change the output.  Are you
experiencing this?  If so, you may have found a GCC bug (I found one once
deep in the bowels of their scheduler a few years ago) and you should do
your civic duty and submit a bug report 8-).

-- Chris

On Wed, 5 Sep 2001, Foo Lim wrote:

> Hi all,
> Is there any way to tell the gcc compiler not to reorder/optimize certain
> parts of the code.  My problem stems when I try to compile a C/C++ program
> with -O3 optimizations (which is required in this project).  I have a
> macro that calls this multiple times:
> #define queue_store(address, value) \
>  asm("list_0store $0, %0, %1" : : "r" (address), "r" (value) );
> An example usage of the above assembly macro would be:
> #define ExampleUse (t1, t2) \
>  queue_store(addr, t1); \
>  queue_store(addr, t2);
> (Actually, the macro that causes the most problems have 5 parameters.)
> The assembly for ExampleUse needs to be together.  What the compiler likes
> to do is reorder the queue_stores into what it thinks is the best way to
> allocate registers and optimize the execution.  Are there any directives I
> can set within ExampleUse() or anything I can do to prevent the
> reordering?
> Thanks In Advance!
> FL
> P.S.  The above is MIPS assembly if that helps, and the list_0store is not
> a standard MIPS instruction.

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