+ * 27.8.2004 Goetz
+ Classes need a flag comparable to visibility of entities.
+ This flag must express whether these classes are accessed from
+ outside, i.e., the fields must have a specific layout.
+ Further it should express whether the outside can allocate classes
+ of the type. Then we can determine whether the class can be turned
+ into a description class by, e.g., rta.
+
+ *
+
+ * 5.7.04 Goetz
+ in free_type: check the types that there is no pointer type that points
+ to the freed type. If so report error.
+
+ + 28.6.04 MMB
+ Div/Mod optimization for constants produces a result that will be optimized
+ again and again :-( Add a flag or a clever encoding so thios does not happen
+
+ + Goetz 10.6.04
+ Error in removing dead code:
+ In an if condition is a loop. We optimized the if condition to Jmp/Bad,
+ the loop now is unreachable. It should be removed by gigo or the like.
+ It remains in the representation as all blocks in the loop have a
+ valid predecessor, i.e., walking from End we find a true loop. We need
+ a pass walking and marking starting at the Start node to remove this loop.
+ Currently scc causes an segmetation fault for this situation.
+
+ + Goetz 10.6.04
+ Error in irscc: If we have an unreachable loop, or a loop
+ resulting from an exiting endless recursion, irscc finds
+ no tail ==> issues an assertion.
+
+ * Goetz 10.6.04
+ Error in interprocedural view: Endless recursions are lost.
+
+ * print routines for all enums!
+
+ * Add flag whether mode is associative, float modes are not!!