[FRONTEND] Add empty return value and remove protect to open the access to contained_tys_vec_t (#514)

Signed-off-by: Mengchi Zhang <mengchi@fb.com>

include/triton/ir/instructions.h

@@ -475,6 +475,7 @@ protected:
   std::string get_eviction_policy_repr() const {
     if (eviction_ == EVICT_FIRST) return ".L1::evict_first";
     if (eviction_ == EVICT_LAST) return ".L2::evict_last";
+    return "";
   }
   EVICTION_POLICY eviction_;
   CACHE_MODIFIER cache_;

include/triton/ir/type.h

@@ -21,7 +21,6 @@ class type {
 public:
   typedef std::vector<unsigned>	         block_shapes_t;
 
-protected:
   typedef std::vector<type*>                  contained_tys_vec_t;
   typedef contained_tys_vec_t::iterator       ty_iterator;
   typedef contained_tys_vec_t::const_iterator const_ty_iterator;