[patch] Make tree-ssa-pre FRE/PRE handle load after store

[Steven Bosscher]

On Wednesday 07 September 2005 09:31, Richard Guenther wrote:
> Where do you make sure you don't remove a trapping load?  Answer:
> we would have had a trapping store in this case - but is it true we can
> kill a trapping load in this case?  Like from a volatile variable?

Volatile expressions are completely ignored.
You are right that I didn't think of trapping loads.  At least
we know for sure that a store happened before the load, but I
am not sure if that means we are safe (e.g. does a store to
NULL trap too??).

Gr.
Steven