64-bit Sparc support and -fstack-check

[Richard Kenner]

It appears this does not work at all.  I suspect it has something to do with
the "stack bias", but I don't understand how the bias is implemented.  It
would seem like it would have to be taken into account at register
elimination level (e.g,, for stack checking to work), but it's done at
virtual register instantiation level, so I'm confused.

To see the problem, compile 

main()
{
   char s[4096];
}

with -m64 -fstack-check and run.

Can somebody who understands this please explain how this is supposed to work?