[Bug fix] matmul bug after reshape+transpose+matmul fuse

paddle/fluid/operators/mkldnn/matmul_mkldnn_op.cc

@@ -235,6 +235,47 @@ class MatMulMKLDNNHandler
         out_strides;
   };
 
+  phi::DDim GetDimForInput(const ExecutionContext& ctx,
+                           std::string input_name) {
+    auto shape = ctx.Attr<std::vector<int>>("fused_reshape_" + input_name);
+    auto axis = ctx.Attr<std::vector<int>>("fused_transpose_" + input_name);
+    auto input_dims = ctx.Input<Tensor>(input_name)->dims();
+    if (!shape.empty() && !axis.empty()) {
+      auto it_zero = std::find(shape.begin(), shape.end(), 0);
+      if (it_zero != shape.end()) {
+        for (uint64_t i = 0; i < shape.size(); i++) {
+          if (shape[i] == 0) {
+            PADDLE_ENFORCE_LT(
+                i, input_dims.size(),
+                paddle::platform::errors::InvalidArgument(
+                    "The index of 0 in fused_reshape_%s ",
+                    "should be less than output dim size, ",
+                    "but the index is %d and output dim size is %d", input_name,
+                    i, input_dims.size()));
+            shape[i] = input_dims.at(i);
+          }
+        }
+      }
+
+      // if "-1" is present then one of reshape dims must be infered
+      auto it_negative = std::find(shape.begin(), shape.end(), -1);
+      if (it_negative != shape.end()) {
+        int64_t dim_product = 1;
+        for (int i = 0; i < input_dims.size(); i++) {
+          dim_product *= input_dims.at(i);
+        }
+
+        int64_t shape_product = std::accumulate(shape.begin(), shape.end(), -1,
+                                                std::multiplies<int>());
+        int index = std::distance(shape.begin(), it_negative);
+        shape[index] = dim_product / shape_product;
+      }
+
+      return input_dims.reshape(shape).transpose(axis);
+    }
+    return input_dims;
+  }
+
   std::pair<phi::funcs::MatDescriptor, memory::dims> GetInputDimsAndStrides(
       const ExecutionContext& ctx, std::string input_name) {
     auto shape = ctx.Attr<std::vector<int>>("fused_reshape_" + input_name);
@@ -342,8 +383,8 @@ class MatMulMKLDNNHandler
 
     batch_size_ = 1;
     if (out_bs > 1 && (IsOutputFused(ctx) || IsInputFused(ctx))) {
-      auto& x_dims = ctx.Input<Tensor>("X")->dims();
-      auto& y_dims = ctx.Input<Tensor>("Y")->dims();
+      auto x_dims = GetDimForInput(ctx, "X");
+      auto y_dims = GetDimForInput(ctx, "Y");
       batch_size_ = x_bs > y_bs ? x_dims[0] : y_dims[0];
       x_bs /= batch_size_;
       y_bs /= batch_size_;