llvm-project

da6f3e6c - [Hexagon] Fix HexagonRDFOpt hang during live-in recomputation (#209986)

[Hexagon] Fix HexagonRDFOpt hang during live-in recomputation (#209986) After HexagonRDFOpt, the compiler recomputed live-in registers for every block in one batch. On large inputs (e.g. kernel builds) this was slow, and on some functions each pass changed the live-in values of other blocks, triggering more passes until the compiler hung (PR #207422). Fix: process blocks one at a time in post-order (successors before predecessors) and stop as soon as nothing changes. Add a pass limit as a safety net to keep compile time bounded in all cases.