Fix autoscheduling trivial lut wrappers

src/autoschedulers/adams2019/DefaultCostModel.cpp

@@ -135,8 +135,8 @@ void DefaultCostModel::enqueue(const Internal::Autoscheduler::FunctionDAG &dag,
 void DefaultCostModel::enqueue(int ns, Runtime::Buffer<float> *schedule_feats, double *cost_ptr) {
     num_stages = ns;
 
-    // We know the most stages that will ever be enqueued from the schedule features
-    internal_assert(pipeline_feat_queue.data() && "Call set_schedule_features before calling enqueue\n");
+    // We know the most stages that will ever be enqueued from the pipeline features
+    internal_assert(pipeline_feat_queue.data() && "Call set_pipeline_features before calling enqueue\n");
     const int max_num_stages = pipeline_feat_queue.dim(2).extent();
     internal_assert(num_stages <= max_num_stages)
         << "schedule features has more stages (" << num_stages

src/autoschedulers/adams2019/FunctionDAG.cpp

@@ -959,7 +959,7 @@ FunctionDAG::FunctionDAG(const vector<Function> &outputs, const Target &target)
             }
 
             node.is_wrapper = node.func.is_wrapper();
-            node.is_input = !node.func.has_update_definition() && node.is_wrapper && !any_incoming_edges;
+            node.is_input = !node.is_output && !node.func.has_update_definition() && node.is_wrapper && !any_incoming_edges;
             node.dimensions = node.func.dimensions();
         }
     }

src/autoschedulers/adams2019/test.cpp

@@ -913,6 +913,30 @@ int main(int argc, char **argv) {
         }
     }
 
+    // A trivial pipeline that just loads from a LUT
+    if (true) {
+        Pipeline p1;
+        Pipeline p2;
+        for (int test_condition = 0; test_condition < 2; test_condition++) {
+            Buffer<uint8_t> lut(256);
+            Func f;
+            f(x) = lut(x);
+
+            f.set_estimate(x, 0, 256);
+
+            if (test_condition) {
+                p2 = Pipeline(f);
+            } else {
+                p1 = Pipeline(f);
+            }
+        }
+
+        if (!test_caching(p1, p2, target)) {
+            std::cerr << "Caching check failed on stencil chain" << std::endl;
+            return 1;
+        }
+    }
+
 #ifdef HALIDE_ALLOW_LEGACY_AUTOSCHEDULER_API
     // Reset environment variables.
     set_env_variable("HL_DISABLE_MEMOIZED_FEATURES", cache_features, /* overwrite */ 1);