llvm-project

a08ac225 - [flang] Implement SIMPLE procedure support (parsing, semantics, diagnostics) (#161285)

[flang] Implement SIMPLE procedure support (parsing, semantics, diagnostics) (#161285) Implement support for the Fortran 2023 `SIMPLE` procedure specifier. This change includes: - Parsing and attribute registration for `SIMPLE` procedures - Adding `SIMPLE` to procedure characteristics - Semantic support for `SIMPLE`, including treating `SIMPLE` procedures as `PURE` (`SIMPLE` implies `PURE`) - Rejecting `SIMPLE` + `IMPURE` combinations - Emitting and reading `SIMPLE` in mod files - Adding parser, semantic, and modfile tests to validate `SIMPLE` behavior `SIMPLE` procedures satisfy `PURE` requirements, while `PURE` procedures do not imply `SIMPLE`.