llvm-project

08396d76 - [Sparc][clang] make `_Complex` ABI GCC-compatible (#212340)

[Sparc][clang] make `_Complex` ABI GCC-compatible (#212340) Modify the ABI of `_Complex` so that it matches GCC for all types, specifically: - On SPARC, a `_Complex` value with an integer element type is now passed and returned packed into the one or two integer registers it fits in, matching GCC. Clang previously passed such a value indirectly and returned it with one part per register. `-fclang-abi-compat=23` restores the previous behavior. - On SPARC64, a `_Complex char` or `_Complex short` is now right-justified in its slot in the parameter array, like every other scalar narrower than a slot, rather than left-justified the way a small struct is. `-fclang-abi-compat=23` restores the previous behavior. Complex integers are a GNU extension, but generally clang is compatible with GCC. Really, you might as well be, deviating can only bite users. I've now validated the implementation with https://github.com/folkertdev/powerpc-complex-abi-validation which compiles various signatures using `_Complex` with GCC and Clang and checks that values make it from one side to the other. related: - https://github.com/rust-lang/rust/issues/154023 - https://github.com/llvm/llvm-project/pull/208917 - https://github.com/llvm/llvm-project/pull/212119