[bugfix] fix some subtleties in the instruction generator

python/dune/perftool/generation/loopy.py

@@ -99,14 +99,15 @@ class _IDCounter:
     count = 0
 
 
-def _insn_cache_key(inames, code=None, expr=None, **kwargs):
+def _insn_cache_key(code=None, expression=None, **kwargs):
     if code:
         return code
-    if expr:
-        return expr
+    if expression:
+        return expression
+    raise ValueError("Please specify either code or expression for instruction!")
 
 
-@generator_factory(item_tags=("insn_id"), no_deco=True, cache_key_generator=_insn_cache_key)
+@generator_factory(item_tags=("insn_id"), cache_key_generator=_insn_cache_key)
 def instruction(code=None, expression=None, **kwargs):
     assert code or expression
     assert not (code and expression)