Traverse down instead of up for const propogation

src/propagate_constant.cpp

@@ -22,22 +22,33 @@ bool skip_propogate(instruction_ref ins)
 
 void propagate_constant::apply(program& p) const
 {
+    for(auto i:iterator_for(p))
+    {
+        if (i->name() != "@literal")
+            continue;
+        if (i->outputs().empty())
+            continue;
         fix([&](auto self, auto ins) {
-        if(not skip_propogate(ins))
+            std::unordered_set<instruction_ref> children(ins->outputs().begin(), ins->outputs().end());
+            for(auto child : children)
             {
-            auto r = ins->eval();
+                if(not skip_propogate(child))
+                {
+                    auto r = child->eval();
                     if(not r.empty())
                     {
-                assert(r.get_shape() == ins->get_shape());
+                        assert(r.get_shape() == child->get_shape());
                         auto l = p.add_literal(r.get_shape(), r.data());
-                p.replace_instruction(ins, l);
-                return;
+                        self(p.replace_instruction(child, l));
                     }
                 } 
-        std::unordered_set<instruction_ref> children(ins->inputs().begin(), ins->inputs().end());
-        for(auto child : children)
+                else
+                {
                     self(child);
-    })(std::prev(p.end()));
+                }
+            }
+        })(i);
+    }
 }
 
 } // namespace MIGRAPHX_INLINE_NS