Cx Dev Log - 2026-03-17

Bringing control flow to a compiler and shipping a more feature-complete frontend branch in one day changes the landscape for the Cx language project. Backend Phase 5: Control Flow Takes Shape We nailed the largest lump commit in backend history on codex/backend-ir-from-main. If you looked under the hood, you'd see 2,559 insertions across three files. Most notable are the 1,656 new lines within lower.rs and the creation of validate.rs with 1,052 lines. Prior to this, IR was pretty much linear—a straight shot from start to finish. Now we’ve integrated true control flow graphs. This means we've got conditional branches, explicit blocks for then/else/merge, and chaining for else-if clauses. Critical here is how SSA (Static Single Assignment) environments are split and merged, ditching phi nodes in favor of block parameters especially for merge points. This shift wasn't new—it harks back to decisions made in Phase 1, but today marked its real-world test and validation. It's cleaner, lighte