Some tests in gcc.c-torture rely on undefined behaviour?

[Ian Lance Taylor]

Diego Novillo <dnovillo@redhat.com> writes:

> The problem is somewhat more widespread now with the tree
> optimizers.  In particular with old test cases.  Some of these
> cases are essentially optimized into empty functions by the time
> we get into the RTL passes.

Hmmm, yeah.

> We would have to audit them all and add enough external
> functions, volatile markers or what-have-you to have them survive
> until RTL.  Not sure if it's worth it.

I'm sure it isn't.

Clearly test cases which we now understand to be invalid should be
changed or removed.  Other than that, I would vote for leaving them
alone.  Unless people are concerned about the number of tests we
have.

(To speed up running the testsuite it would probably be more useful in
any case to put some time into running test cases in parallel on
native systems.  Tcl has enough support for processes that this
shouldn't be very hard.  It would mostly be a bookkeeping issue, I
think.)

Ian