Re: Call for compiler help/advice: atomic builtins for v3

[Paolo Carlini <pcarlini at suse dot de>]

Richard Henderson wrote:

>On Mon, Nov 07, 2005 at 03:45:46AM +0100, Paolo Carlini wrote:
>  
>
>>Richard, sorry, I don't agree, on second thought. You are not
>>considering that the idea is using a "smart" libgcc, a la glibc, as per
>>Mark and Uli messages.
>>    
>>
>Yes, I am.  I stand by my statement: libgcc is the wrong level at
>which to attack this.  If you want to make libstdc++ auto-detect
>the machine, that's fine.  But it has to be in code specific to
>that library.
>  
>
I don't see, however, a detailed scenario where something can go wrong.
If you mean you have a "feeling" that it's better not to touch libgcc,
it's another thing, I respect your feelings about the architecture of
gcc, of course, but you have yet to provide a specific situation where
things can go wrong.

To repeat, my point is that in most of the cases application would not
have anything inlined and the choice would be deferred completely to
libgcc, which knows the machine. If, on the other hand, something is
inlined in the application (an atomic operation) had better to be ok for
that machine in the first place (i.e., if you pass -march=i686, then you
need an i686).

Paolo.