Remove dead branches when compiling to C

Specifically remove branches where flow-typing implies false, as this
allows the optimizer to prove anything, which can result in nonsense
code. This does incur something of a performance hit.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/anf.ml b/src/anf.ml
index 38c77e0b..5db836e9 100644
--- a/src/anf.ml
+++ b/src/anf.ml
@@ -436,6 +436,8 @@ and pp_aval = function
 
 let ae_lit lit typ = AE_val (AV_lit (lit, typ))
 
+let is_dead_aexp (AE_aux (_, env, _)) = prove __POS__ env nc_false
+
 (** GLOBAL: gensym_counter is used to generate fresh identifiers where
    needed. It should be safe to reset between top level
    definitions. **)