There are two errors know to date and one porblem.

Errors:

1) Using typedef to create differents names for the same type will
confuse the optimization into thinking that they are different
types.

This is a know big issue and not a surprise.

2) Some local declarations go missing for not apparient reason.
To verify this is the case in a suspicious situation uncoment
the DEBUG statemest annotated with "test_1_8" and you'll see in the
stderr output that there are no declarations associate with the
function of interest.

This was a surprise and will require a lot of debugging to track
dowm the root case of the problem. If you wish to see my test case
I will send it to you.

Problem:

If you invoke any of the structure reorg optimizations
(e.g. -fipa-structure-reorg), you'll need to include the options
"-flto -flto-partition=one". The problem is that struction reorg
will unfortunenately run if only "-flto" is included with a
struct reorg option but it will be insane and not function correctly.

I've not found a way to address this yet but I'm hopeful that this
is someing we can cope with.