From d46b4f75146ee63b8e60215abea431d0aa8ea3c4 Mon Sep 17 00:00:00 2001
From: "A. Unique TensorFlower" <gardener@tensorflow.org>
Date: Tue, 2 Jul 2019 15:04:52 -0700
Subject: [PATCH] Metal: More information on graph processing.

PiperOrigin-RevId: 256247206
---
 tensorflow/lite/delegates/gpu/metal/compiled_model.cc | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tensorflow/lite/delegates/gpu/metal/compiled_model.cc b/tensorflow/lite/delegates/gpu/metal/compiled_model.cc
index 97f8dfc6fa2..872491afdff 100644
--- a/tensorflow/lite/delegates/gpu/metal/compiled_model.cc
+++ b/tensorflow/lite/delegates/gpu/metal/compiled_model.cc
@@ -573,7 +573,14 @@ Status ValidateOptimizeModel(const std::vector<ValueId>& input_buffers,
       GetMissingOutputBufferIds(output_buffers, sorted_chains);
   info.gpu_tasks_count = static_cast<int>(sorted_chains.size());
   if (sorted_chains.empty()) {
-    return InternalError("Empty chains");
+    const std::string message =
+        "No valid operations in the graph.\nInput operations count " +
+        std::to_string(info.operations_count) + "\nUnused operations " +
+        std::to_string(info.unused_operations.size()) + "\nUnused inputs " +
+        std::to_string(info.unused_input_buffer_ids.size()) +
+        "\nMissing output buffers " +
+        std::to_string(info.missing_output_buffer_ids.size());
+    return InternalError(message);
   }
   for (const auto& chain : sorted_chains) output->push_back(FuseChain(chain));
   return OkStatus();