RSSA is an IntermediateLanguage, translated from SSA2 by ToRSSA, optimized by RSSASimplify, and translated by ToMachine to Machine.
Description
RSSA is a IntermediateLanguage that makes representation decisions explicit.
Type Checking
The new type language is aimed at expressing bit-level control over
layout and associated packing of data representations. There are
singleton types that denote constants, other atomic types for things
like integers and reals, and arbitrary sum types and sequence (tuple)
types. The big change to the type system is that type checking is now
based on subtyping, not type equality. So, for example, the singleton
type 0xFFFFEEBB whose only inhabitant is the eponymous constant is a
subtype of the type Word32.
Details and Notes
SSA is an abbreviation for Static Single Assignment. The RSSA IntermediateLanguage is a variant of SSA.