move alias declaration into preamble

python/dune/codegen/blockstructured/accumulation.py

 from dune.codegen.blockstructured.tools import sub_element_inames
-from dune.codegen.generation import accumulation_mixin, instruction
+from dune.codegen.generation import accumulation_mixin, instruction, preamble
 from dune.codegen.loopy.target import dtype_floatingpoint
 from dune.codegen.options import get_form_option
 from dune.codegen.pdelab.geometry import world_dimension, name_intersection_geometry_wrapper
@@ -28,16 +28,13 @@ def name_accumulation_alias(container, accumspace):
     k = get_form_option("number_of_blocks")
     p = accumspace.element.degree()
 
+    @preamble
     def _add_alias_insn(name):
         dim = world_dimension()
         element_stride = tuple(p * (p * k + 1)**i for i in range(0, dim))
         index_stride = tuple((p * k + 1)**i for i in range(0, dim))
         globalarg(name, shape=(k,) * dim + (p + 1,) * dim, strides=element_stride + index_stride, managed=True)
-        code = "auto {} = &{}.container()({},0);".format(name, container, accumspace.lfs.name)
-        instruction(within_inames=frozenset(),
-                    code=code,
-                    read_variables=frozenset({container}),
-                    assignees=frozenset({name}))
+        return "auto {} = &{}.container()({},0);".format(name, container, accumspace.lfs.name)
 
     _add_alias_insn(name)
     _add_alias_insn(name_tail)

python/dune/codegen/blockstructured/argument.py

 from dune.codegen.generation import (kernel_cached,
-                                     valuearg, instruction, globalarg)
+                                     valuearg, globalarg, preamble)
 from dune.codegen.options import get_form_option
 from dune.codegen.pdelab.argument import CoefficientAccess
 from dune.codegen.blockstructured.tools import micro_index_to_macro_index, sub_element_inames
@@ -10,17 +10,18 @@ import pymbolic.primitives as prim
 
 def name_alias(container, lfs, element):
     name = container + "_" + lfs.name + "_alias"
-    k = get_form_option("number_of_blocks")
-    p = element.degree()
-    dim = world_dimension()
-    element_stride = tuple(p * (p * k + 1)**i for i in range(0, dim))
-    index_stride = tuple((p * k + 1)**i for i in range(0, dim))
-    globalarg(name, shape=(k,) * dim + (p + 1,) * dim, strides=element_stride + index_stride, managed=True)
-    code = "const auto {} = &{}({},0);".format(name, container, lfs.name)
-    instruction(within_inames=frozenset(),
-                code=code,
-                read_variables=frozenset({container}),
-                assignees=frozenset({name}))
+
+    @preamble
+    def _add_alias_insn(name):
+        k = get_form_option("number_of_blocks")
+        p = element.degree()
+        dim = world_dimension()
+        element_stride = tuple(p * (p * k + 1)**i for i in range(0, dim))
+        index_stride = tuple((p * k + 1)**i for i in range(0, dim))
+        globalarg(name, shape=(k,) * dim + (p + 1,) * dim, strides=element_stride + index_stride, managed=True)
+        return "const auto {} = &{}({},0);".format(name, container, lfs.name)
+
+    _add_alias_insn(name)
     return name