Common sub-expression elimination for inverse query evaluation

Provided herein are optimizations for an instruction tree of an inverse query engine. Secondary sub-expression elimination trees are provided, which are data structures configured to include nodes that allow for temporary variables that hold processing context or state for idempotent fragments of query expression(s). As such, when sub-paths for a query expression are processed against a message, the processing context may be stored within nodes of one or more sub-expression elimination trees. The next time this same fragment is processed, regardless of where it appears within the instruction tree, the data structure is accessed to identify and retrieve the state information such that the idempotent fragment is only calculated or evaluated once.