RTL alias analysis

[Richard Henderson]

On Fri, Jan 20, 2006 at 06:39:21PM +0100, Steven Bosscher wrote:
> FWIW, I don't believe this is a "fix", but rather a solid work-around
> for the problem.  I'm still trusting rth's superior compiler brain and
> GCC knowledge to ultimately be ingredients in a real fix ;-)

I don't think it's quite solid for a workaround.

And, unfortunately, I can't think of any "good" solution to 
the problem.  The only only way to prevent some of the 
potential problems is to prevent moving memory operations
across block boundaries, which would be a real joy for our
optimizers.

In some cases I'm sure we could see no ill effects by adding
memory barriers strategically, and in others I'm sure we'd
kill performance.


r~