On Mon, 30 Mar 2020 at 06:54, Daniel Brodsky <dnbrd...@gmail.com> wrote:
> Using `#pragma clang diagnostic ignored > "-Wtautological-type-limit-compare"` suppresses the errors (on Clang > 9). I could go and drop that in for the problem areas? There's only a > few so it wouldn't be a major change. I'm thinking of adding a macro > like this: > #define PRAGMA(x) _Pragma(stringify(x)) > #define IF_IGNORE_TYPE_LIMIT(statement) \ > PRAGMA(clang diagnostic push) \ > PRAGMA(clang diagnostic ignored "-Wtautological-type-limit-compare") \ > if (statement) \ > PRAGMA(clang diagnostic pop) This is not an in-principle objection, but we have found in the past that various gcc/clang implementations of _Pragma() are simply buggy when used inside macros; see the comments on this patch attempt: https://patchwork.kernel.org/patch/10620079/ (one of which has a link to half a dozen gcc bug reports involving _Pragma and three clang bugs). For that particular case the approach we eventually took was to only use the _Pragma() stuff on clang because gcc mishandled it and luckily the spurious warning was clang-only. It's a shame, because the whole point of _Pragma() is to let you do this kind of thing in a macro, but the actual implementations in compilers are clearly just not fit-for-purpose. So if you do go down this path please make sure you test it on a wide variety of different clang and gcc versions. thanks -- PMM
