Dead-code elimination can't remove string copy insns?

[Naveen Sharma, Noida]

> >> but the alias information should be sufficient to see that 
> the memory region being written into is on the stack, and unused past 
> this insn, hence the store is dead and can be deleted.
> 
> > It should, but we don't do that currently.
> 
> Do you have a sense for how hard this would be to implement?  Is it
> something that's done on tree-ssa, so there's no point adding it in
> mainline?  Will Naveen's stack-slot allocator help?

The stack pseudos rely on the flow infrastructure.
At the moment, the dead stores to the stack should be removed 
in the tail blocks (but not for BLKmode mems). 
But it should be simple to teach flow analysis to handle this 
case with stack pseudos.

Best Regards,
  Naveen Sharma.