[Bug debug/66714] ICE in loc_list_from_tree with -g

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66714

--- Comment #15 from vries at gcc dot gnu.org ---
My guess at this point is that the problem is that in 
replace_block_vars_by_duplicates, we replace the old decls in the block with
new decls, but that the value-exprs that we copy from the old to the new decls
still contain the old decls.