[Bug optimization/12108] wrong code generated in the presence of asm("...")

[anton at a0 dot complang dot tuwien dot ac dot at]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12108



------- Additional Comments From anton at a0 dot complang dot tuwien dot ac dot at  2003-08-30 17:20 -------
Subject: Re:  wrong code generated in the presence of asm("...")

pinskia at gcc dot gnu dot org wrote:
> I think the code is wrong because the asm is not marked as volatile so the schedular is free to 
> move it around.

No: from the gcc manual (node Extended asm):

|   An `asm' instruction without any operands or clobbers (an "old
|style" `asm') will be treated identically to a volatile `asm'
|instruction.

> Can you try this:
> int foo(int);
> main()
> {
>   if(foo(0)!=16)
>     abort();
> }
> int y;
> int foo(int x)
> {
>   if (x) {
>   label1:
>     asm volatile (".skip 16"); /* or ".space 16" or somesuch */
>   label2:
> ;
>   }
>   return (&&label2)-(&&label1);
> }

Same result.

- anton