aqjune added a comment. Hello all,
I'm a messenger of @hyeongyukim's two patches that allow clang to turn on noundef analysis by default. The noundef analysis flag was added by D81678 <https://reviews.llvm.org/D81678> in the past. Its goal is to mark arguments and return values in C/C++ as `noundef` if legal. Attaching `noundef` is beneficial because it allows quite a few optimizations that are unsound w.r.t. undef or poison (they are usually guarded with `isGuaranteedNotToBeUndefOrPoison` check). Since the fact that arg/ret values are noundef is derived from the source language (C/C++)'s specification, the information is permanently lost unless explicitly attached by clang. Previously, the flag was not activated by default because it required a lot of tests to be updated, possibly raising conflicts with downstream patches (discussed in this thread: D82317 <https://reviews.llvm.org/D82317>) To handle the conflict, I'd like to update requested tests to simply adding `-disable-noundef-analysis` at `// RUN: %clang_cc1 ...` rather than fixing the whole text. I'll talk about this more in the second patch (D108453 <https://reviews.llvm.org/D108453>). Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D105169/new/ https://reviews.llvm.org/D105169 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
