mysterymath marked an inline comment as done. mysterymath added inline comments.
================ Comment at: clang/lib/Headers/limits.h:55 #define UCHAR_MAX (__SCHAR_MAX__*2 +1) -#define USHRT_MAX (__SHRT_MAX__ *2 +1) +#define USHRT_MAX (__SHRT_MAX__ * 2U + 1U) #define UINT_MAX (__INT_MAX__ *2U +1U) ---------------- aaron.ballman wrote: > It's worth double-checking that this still gives the correct type for the > macro: > > C2x 5.2.4.2.1p2: For all unsigned integer types for which <limits.h> or > <stdint.h> define a macro with suffix _WIDTH holding its width N, there is a > macro with suffix _MAX holding the maximal value 2N − 1 that is representable > by the type and that has the same type as would an expression that is an > object of the corresponding type converted according to the integer > promotions. ... Ah, thanks; it hadn't occurred to me that the type of the expression would be specified in the standard. It could be either `unsigned int` or `int`, depending on the target. The most straightforward approach I could think of to produce the right type is: 1) Perform the arithmetic in `unsigned int` to produce the right value 2) Cast to `unsigned short` to produce the right type 3) Directly perform integer promotion using unary plus The use of unary plus is a bit odd here, but it seems like the most direct way to express the logic, and the overall expression seems less fragile than the `#if` alternative. I've added a comment to explain this as well. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D144218/new/ https://reviews.llvm.org/D144218 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
