Remove operator-(size_t, dyn_dim), add tests

The operator-(size_t ,dyn_dim) is not used and somewhat bug prone

src/include/migraphx/shape.hpp

@@ -112,7 +112,6 @@ struct shape
         friend dynamic_dimension operator+(const dynamic_dimension& x, const std::size_t& y);
         friend dynamic_dimension operator+(const std::size_t& x, const dynamic_dimension& y);
         friend dynamic_dimension operator-(const dynamic_dimension& x, const std::size_t& y);
-        friend dynamic_dimension operator-(const std::size_t& x, const dynamic_dimension& y);
     };
 
     static const std::vector<type_t>& types();

src/shape.cpp

@@ -541,10 +541,6 @@ shape::dynamic_dimension operator-(const shape::dynamic_dimension& x, const std:
 {
     return {x.min - y, x.max - y, x.opt == 0 ? 0 : x.opt - y};
 }
-shape::dynamic_dimension operator-(const std::size_t& x, const shape::dynamic_dimension& y)
-{
-    return {x - y.min, x - y.max, y.opt == 0 ? 0 : x - y.opt};
-}
 
 bool operator==(const shape& x, const shape& y)
 {

test/shape_test.cpp

@@ -174,6 +174,28 @@ TEST_CASE(dynamic_dimension_size_t_compares)
     EXPECT(static_cast<std::size_t>(2) != b);
 }
 
+TEST_CASE(dynamic_dimension_add_sub_fixed)
+{
+    using migraphx::shape;
+    auto a = shape::dynamic_dimension{2, 5, 2};
+
+    auto b = shape::dynamic_dimension{3, 6, 3};
+    EXPECT((a + 1) == b);
+    EXPECT((1 + a) == b);
+    EXPECT((b - 1) == a);
+
+    auto c = shape::dynamic_dimension{4, 7, 4};
+    EXPECT((a + 2) == c);
+    EXPECT((2 + a) == c);
+    EXPECT((c - 2) == a);
+
+    auto d = shape::dynamic_dimension{4, 8, 0};
+    auto e = shape::dynamic_dimension{2, 6, 0};
+    EXPECT((d - 2) == e);
+    EXPECT((e + 2) == d);
+    EXPECT((2 + e) == d);
+}
+
 TEST_CASE(test_shape_dynamic_errors)
 {
     using migraphx::shape;