add dynamic dimension in the shape class

src/include/migraphx/shape.hpp

@@ -54,6 +54,20 @@ struct shape
     MIGRAPHX_SHAPE_VISIT_TYPES(MIGRAPHX_SHAPE_GENERATE_GET_TYPE)
 #undef MIGRAPHX_SHAPE_GENERATE_GET_TYPE
 
+    // dynamic dimension to support dynamic shape
+    struct dynamic_dimension
+    {
+        std::size_t min = 0;
+        std::size_t max = 0;
+        std::size_t opt = 0;
+        
+        // is the dimension fixed
+        bool is_fixed() const;
+
+        // does the dimension have an optimal size
+        bool has_optimal() const;
+    };
+
     template <class T>
     struct get_type<const T> : get_type<T>
     {
@@ -84,6 +98,9 @@ struct shape
 
     shape(const std::vector<shape>& subs);
 
+    // constructor for dynamic shape
+    shape(type_t t, std::vector<dynamic_dimension> dims);
+
     static shape
     from_permutation(type_t t, const std::vector<std::size_t>& l, const std::vector<int64_t>& perm);
     type_t type() const;

src/shape.cpp

@@ -50,6 +50,7 @@ struct shape_impl
     std::vector<std::size_t> m_strides = {};
     std::vector<shape> m_shapes        = {};
     bool m_standard                    = false;
+    std::vector<shape::dynamic_dimension> dynamic_dims = {};
 
     void calculate_strides()
     {