https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114285
--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Antoni from comment #4) > A load in LLVM returns undef, so it is not UB. The problem is in > rustc_codegen_gcc itself. Right, GCC gimple semantics are different from LLVM semantics. GCC gimple semantics are in my opinion the better semantics really. How to handle things like Rust semantics with the GCC gimple semantics is an open question. Basically if I understand correctly Rust semantics depend on LLVM semantics which seems like wrong approach for a security language. undef vs UB is a small semantic difference that makes it hard to program rust really :).
