gustedt added a comment. >> Also discussing consequences for `va_arg` functions such as `printf` would >> be nice. > > Does the information in the `Passing and Returning an Object` section > suffice, or are there more details you're looking for there?
The narrow `_BitInt` types are not promoted to `int` for arithmetic. For the function call ABI we would need to know if the same strategy holds for `va_arg` parameters. For each of these types with representing standard integer type `T` two scenarios would be possible - When passed to a `va_arg` function the same rules for `T` as an argument for a prototyped function parameter apply. - When passed to a `va_arg` function the value is promoted as if it where a `T`, that is in general there is a promotion to `int`. This has in particular implications to whether or not the `wN` length modifier for `printf` and `scanf` can be used for narrow `_BitInt` types or not: in the first scenario that would not be possible in the second in would be possible without problems. I would be much in favor of the second choice, `va_arg` functions usually are not made to handle narrow input well. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D115169/new/ https://reviews.llvm.org/D115169 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
