The helper functions to fold over instructions and expressions in
test/OptSupport have a bug where they would not recurse for complex
expressions. And since testing/Live module depends on it, complex
expressions would not be fully analyzed, leading to removal of code
that is *not* dead, e.g.,
  var1 = m[0]
  var1 = m[var1] + m[var1]
would get rewritten to just
  var1 = m[var1] + m[var1]
which is clearly wrong.

Note that this bug affects only Hoopl's tests.