This is the `ext_vector_type` alternative to D81083.
This patch extends Clang to allow 'bool' as a valid vector element type
(attribute ext_vector_type) in C/C++.
This is intended as the canonical type for SIMD masks and facilitates
clean vector intrinsic declarations. Vectors of i1 are supported on IR
level and below down to many SIMD ISAs, such as AVX512, ARM SVE (fixed
vector length) and the VE target (NEC SX-Aurora TSUBASA).
The RFC on cfe-dev: https://lists.llvm.org/pipermail/cfe-dev/2020-May/065434.html
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D88905
This patch implements the conditional select operator for
ext_vector_types in C++. It does so by using the same semantics as for
C.
D71463 added support for the conditional select operator for VectorType
in C++. Unfortunately the semantics between ext_vector_type in C are
different to VectorType in C++. Select for ext_vector_type is based on
the MSB of the condition vector, whereas for VectorType it is `!= 0`.
This unfortunately means that the behavior is inconsistent between
ExtVectorType and VectorType, but I think using the C semantics for
ExtVectorType in C++ as well should be less surprising for users.
Reviewed By: erichkeane, aaron.ballman
Differential Revision: https://reviews.llvm.org/D98055
Simon Moll