simpl_phase phase names iter
= CoreDoPasses
- [ maybe_strictness_before phase
+ $ [ maybe_strictness_before phase
, CoreDoSimplify iter
(base_mode { sm_phase = Phase phase
, sm_names = names })
- , maybe_rule_check (Phase phase)
- ]
+ , maybe_rule_check (Phase phase) ]
+
+ -- Vectorisation can introduce a fair few common sub expressions involving
+ -- DPH primitives. For example, see the Reverse test from dph-examples.
+ -- We need to eliminate these common sub expressions before their definitions
+ -- are inlined in phase 2. The CSE introduces lots of v1 = v2 bindings,
+ -- so we also run simpl_gently to inline them.
+ ++ (if dopt Opt_Vectorise dflags && phase == 3
+ then [CoreCSE, simpl_gently]
+ else [])
vectorisation
= runWhen (dopt Opt_Vectorise dflags) $