fix[next]: DaCe field addressing in builtin_neighbors (#1349)

Bugfix in DaCe backend to make field addressing in builtin_neighbors consistent with the canonical representation (field dimensions alphabetically sorted).

src/gt4py/next/program_processors/runners/dace_iterator/itir_to_tasklet.py

@@ -243,10 +243,8 @@ def builtin_neighbors(
     )
     # select full shape only in the neighbor-axis dimension
     field_subset = [
-        f"0:{sdfg.arrays[iterator.field.data].shape[idx]}"
-        if dim == table.neighbor_axis.value
-        else f"i_{dim}"
-        for idx, dim in enumerate(iterator.dimensions)
+        f"0:{shape}" if dim == table.neighbor_axis.value else f"i_{dim}"
+        for dim, shape in zip(sorted(iterator.dimensions), sdfg.arrays[iterator.field.data].shape)
     ]
     state.add_memlet_path(
         iterator.field,
@@ -575,6 +573,7 @@ def _visit_deref(self, node: itir.FunCall) -> list[ValueExpr]:
             return iterator
 
         args: list[ValueExpr]
+        sorted_dims = sorted(iterator.dimensions)
         if self.context.reduce_limit:
             # we are visiting a child node of reduction, so the neighbor index can be used for indirect addressing
             result_name = unique_var_name()
@@ -596,7 +595,7 @@ def _visit_deref(self, node: itir.FunCall) -> list[ValueExpr]:
             # if dim is not found in iterator indices, we take the neighbor index over the reduction domain
             flat_index = [
                 f"{iterator.indices[dim].data}_v" if dim in iterator.indices else index_name
-                for dim in sorted(iterator.dimensions)
+                for dim in sorted_dims
             ]
             args = [ValueExpr(iterator.field, iterator.dtype)] + [
                 ValueExpr(iterator.indices[dim], iterator.dtype) for dim in iterator.indices
@@ -629,11 +628,9 @@ def _visit_deref(self, node: itir.FunCall) -> list[ValueExpr]:
             return [ValueExpr(value=result_access, dtype=iterator.dtype)]
 
         else:
-            sorted_index = sorted(iterator.indices.items(), key=lambda x: x[0])
-            flat_index = [
-                ValueExpr(x[1], iterator.dtype) for x in sorted_index if x[0] in iterator.dimensions
+            args = [ValueExpr(iterator.field, iterator.dtype)] + [
+                ValueExpr(iterator.indices[dim], iterator.dtype) for dim in sorted_dims
             ]
-            args = [ValueExpr(iterator.field, iterator.dtype), *flat_index]
             internals = [f"{arg.value.data}_v" for arg in args]
             expr = f"{internals[0]}[{', '.join(internals[1:])}]"
             return self.add_expr_tasklet(list(zip(args, internals)), expr, iterator.dtype, "deref")