antoniofrighetto wrote: > Sorry, can you back up and explain the root problem you're trying to solve? > You have a platform where we're emitting accesses to `errno` as if it weren't > an `int`? What does it look like in source?
Oh, sorry for not providing context earlier. The reasoning behind is to allow certain optimizations involving errno-writing libcalls to occur, if we are able to prove the involved memory location does not alias errno (e.g., because we are accessing a float-typed pointer). IIUC, in standard C, errno is an int, so all legitimate accesses must use int-compatible types (or otherwise violating strict aliasing). Hence, we should be able to leverage TBAA and prove not aliasing with errno, if we do not alias for any nodes belonging to `!llvm.errno.tbaa` (which is presumably gathering all int-based nodes; this should require confirmation). Original miscompilation issue: https://github.com/llvm/llvm-project/issues/114772, previous discussion at: https://discourse.llvm.org/t/rfc-modelling-errno-memory-effects/82972. https://github.com/llvm/llvm-project/pull/125258 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
