fixed conv+bias pattern match causing mxnet tests to fail. (#647)

src/ngraph/runtime/cpu/pass/cpu_fusion.cpp

@@ -644,9 +644,31 @@ void ngraph::runtime::cpu::pass::CPUFusion::construct_conv_bias()
         std::shared_ptr<Node> nn;
 
         auto conv = std::dynamic_pointer_cast<op::Convolution>(m.match_root()->get_input_op(0));
-        auto bias = m.match_root()->get_input_op(1)->get_input_op(0);
-        auto conv_bias = std::shared_ptr<Node>(new op::ConvolutionBias(conv, bias));
-        return conv_bias;
+        if (conv->get_input_shape(0).size() == 4)
+        {
+            auto bias = m.match_root()->get_input_op(1)->get_input_op(0);
+            auto bias_shape = bias->get_shape();
+            if (bias_shape.size() > 1)
+            {
+                NGRAPH_DEBUG
+                    << "mpattern = " << m.match_root()->get_name()
+                    << "conv_bias bias shape != 1, requires reshape to match filter count.";
+                ngraph::AxisVector order(bias_shape.size());
+                std::iota(begin(order), end(order), 0);
+                auto bias_reshape =
+                    std::make_shared<op::Reshape>(bias, order, Shape{conv->get_input_shape(1)[0]});
+                auto conv_bias = std::shared_ptr<Node>(new op::ConvolutionBias(conv, bias_reshape));
+                return conv_bias;
+            }
+            else
+            {
+                auto conv_bias = std::shared_ptr<Node>(new op::ConvolutionBias(conv, bias));
+                return conv_bias;
+            }
+        }
+        NGRAPH_DEBUG << "mpattern = " << m.match_root()->get_name()
+                     << "conv_bias fusion skipped due to input rank size != 4.";
+        return std::shared_ptr<Node>(nullptr);
     };
 
     auto m = std::make_shared<ngraph::pattern::Matcher>(p_conv_bias, callback);