The scheduler knows that insns with different COND_EXEC conditions don't
conflict and can be scheduled independently. Unfortunately, sched-deps.c
does not try to keep the conditions valid as it progresses. For example,

[B0] A0 = [A1]
     B0 = something
[!B0] [A2] = A0

The first and third insns have opposite conditions, so the scheduler
decides they are independent. For most targets this isn't a problem, as
the insn in the middle will produce enough dependencies to ensure the
right order. However, on C6X, order alone isn't sufficient due to the
exposed pipeline: we also need to ensure that the latencies are observed.


Bernd