On Fri, 19 Jun 2026, Paul Koning via cctalk wrote: > No part, and I don't recall that any ever did. There are a number of > internal representations inside GCC, the specific set and nature of > which has changed over time. There's a tree representation, and > something called "GIMPLE" (don't remember what that means) and later on > there is "RTL" which is what the back ends consume. Those intermediate > forms I think are meant to be generic representations of the program, > through various transformations. The assorted optimization schemes act > on these representations. I suspect part of the reason for multiple > representations is that some optimizations are more easly done on one of > them and others on a different one.
Original GCC was a plain RTL compiler, other internal representations were only retrofitted later on, in early 2000s. You are right in that their use enabled optimisations which were infeasible with RTL. Maciej
