aykevl added a comment. I need to recompile LLVM to test this patch so it might take a while.
In D81285#2082517 <https://reviews.llvm.org/D81285#2082517>, @atrosinenko wrote: > In D81285#2082394 <https://reviews.llvm.org/D81285#2082394>, @aykevl wrote: > > > Also note that the libgcc documentation does not always reflect the real > > world. For example, `__divmodsi4` on AVR libgcc has a very different > > signature: it returns both the division result and the remainder in > > registers. > > > Do you mean some special calling convention not used outside the > `libgcc`/`clang_rt`? MSP430 has one as well. And I still have to decide how > to express for //some of// generic C implementations that they should use > that special calling convention on MSP430 without cluttering the sources with > `O(target count)` complexity. :) Meanwhile, some hacks do exist for ARM > target already. I don't mean a separate calling convention, although AVR has that as well. Rather, that the builtin has a different function signature. This signature is a bit hard to express in C so you might consider it a different ABI I guess. I implemented it in C by packing the two return values in a single `uint64_t`. ================ Comment at: compiler-rt/lib/builtins/int_lib.h:112 -uint32_t __inline __builtin_ctz(uint32_t value) { +int __inline __builtin_ctz(uint32_t value) { unsigned long trailing_zero = 0; ---------------- atrosinenko wrote: > aykevl wrote: > > Why `int` and not `native_int` here? > Just to use more "textually identical" prototype as for an actual > `__builtin_ctz` from GCC. On the other hand, such dilemma could be one of > arguments against `native_int`. Yes, that makes sense. It is actually defined with `int` in [the official documentation](https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html), and because this is at the C language level and not at the ABI/target level, it's not one of the "int but really int32_t" types. That said, I think the parameter should also be `unsigned int` instead of `uint32_t`. And the same goes for the other types below. Although, in practice, it doesn't really matter as it's all MSVC with 32-bit int everywhere. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D81285/new/ https://reviews.llvm.org/D81285 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
