[clang] [HLSL] Convert vectors to bool for unary ! (PR #163857)

[Justin Bogner via cfe-commits]

bogner wrote:

I'm surprised that this is HLSL specific, though it obviously falls into the minutiae of a few different language extensions here.

Is the behaviour in C++ mode here intentional, or did it just follow the opencl behaviour from ext_vector? The change that introduced logical not for vector isn't very clear about this, but may be matching GCC, I'm not sure: https://reviews.llvm.org/D80979.

In any case, I think we should probably investigate whether we're doing the "right" thing in C++ mode separately from the change itself.

https://github.com/llvm/llvm-project/pull/163857