Fix the issue with cpp codegen, where it currently cannot handle inputs

like:
```c++
cpp.reshape_strides(Range([(0, 4, 1), (0, 5, 1)]), None, None, [2, 3, 5])
```
and crashes with an index error.

dace/codegen/targets/cpp.py

@@ -417,6 +417,7 @@ def reshape_strides(subset, strides, original_strides, copy_shape):
     dims = len(copy_shape)
 
     reduced_tile_sizes = [ts for ts, s in zip(subset.tile_sizes, original_copy_shape) if s != 1]
+    reduced_tile_sizes += [1] * (dims - len(reduced_tile_sizes))  # Pad the remainder with 1s to maintain dimensions.
 
     reshaped_copy = copy_shape + [ts for ts in subset.tile_sizes if ts != 1]
     reshaped_copy[:len(copy_shape)] = [s / ts for s, ts in zip(copy_shape, reduced_tile_sizes)]

tests/codegen/targets/cpp_test.py

@@ -0,0 +1,75 @@
+import unittest
+from functools import reduce
+from operator import mul
+
+from dace.codegen.targets import cpp
+from dace.subsets import Range
+
+
+class ReshapeStrides(unittest.TestCase):
+    def test_multidim_array_all_dims_unit(self):
+        r = Range([(0, 0, 1), (0, 0, 1)])
+
+        # To smaller-sized shape
+        target_dims = [1]
+        self.assertEqual(r.num_elements_exact(), reduce(mul, target_dims))
+        reshaped, strides = cpp.reshape_strides(r, None, None, target_dims)
+        self.assertEqual(reshaped, [1])
+
+        # To equal-sized shape
+        target_dims = [1, 1]
+        self.assertEqual(r.num_elements_exact(), reduce(mul, target_dims))
+        reshaped, strides = cpp.reshape_strides(r, None, None, target_dims)
+        self.assertEqual(reshaped, [1, 1])
+
+        # To larger-sized shape
+        target_dims = [1, 1, 1]
+        self.assertEqual(r.num_elements_exact(), reduce(mul, target_dims))
+        reshaped, strides = cpp.reshape_strides(r, None, None, target_dims)
+        self.assertEqual(reshaped, [1, 1, 1])
+
+    def test_multidim_array_some_dims_unit(self):
+        r = Range([(0, 1, 1), (0, 0, 1)])
+
+        # To smaller-sized shape
+        target_dims = [2]
+        self.assertEqual(r.num_elements_exact(), reduce(mul, target_dims))
+        reshaped, strides = cpp.reshape_strides(r, None, None, target_dims)
+        self.assertEqual(reshaped, target_dims)
+
+        # To equal-sized shape
+        target_dims = [2, 1]
+        self.assertEqual(r.num_elements_exact(), reduce(mul, target_dims))
+        reshaped, strides = cpp.reshape_strides(r, None, None, target_dims)
+        self.assertEqual(reshaped, target_dims)
+
+        # To equal-sized shape
+        target_dims = [2, 1, 1]
+        self.assertEqual(r.num_elements_exact(), reduce(mul, target_dims))
+        reshaped, strides = cpp.reshape_strides(r, None, None, target_dims)
+        self.assertEqual(reshaped, target_dims)
+
+    def test_multidim_array_different_shape(self):
+        r = Range([(0, 4, 1), (0, 5, 1)])
+
+        # To smaller-sized shape
+        target_dims = [30]
+        self.assertEqual(r.num_elements_exact(), reduce(mul, target_dims))
+        reshaped, strides = cpp.reshape_strides(r, None, None, target_dims)
+        self.assertEqual(reshaped, target_dims)
+
+        # To equal-sized shape
+        target_dims = [15, 2]
+        self.assertEqual(r.num_elements_exact(), reduce(mul, target_dims))
+        reshaped, strides = cpp.reshape_strides(r, None, None, target_dims)
+        self.assertEqual(reshaped, target_dims)
+
+        # To equal-sized shape
+        target_dims = [3, 5, 2]
+        self.assertEqual(r.num_elements_exact(), reduce(mul, target_dims))
+        reshaped, strides = cpp.reshape_strides(r, None, None, target_dims)
+        self.assertEqual(reshaped, target_dims)
+
+
+if __name__ == '__main__':
+    unittest.main()