Optionally, if I have enough time and it proves to be really useful: use #symbolic #execution to determine if #decompiled code corresponds to original sources code. It doesn't look trivial at all, as codes written by humans tends to be much more verbose, logical, etc, than codes generated by compilers.

In summary: it's hard to compare, say, humans written Abstract Syntax Trees against the #AST given by an optimising #decompiler taking as input code optimised by a #compiler.