Request LLVM to implement _CountLeadingZeros and _CountLeadingZeros64 when targeting ARM/ARM64 #1586
Description
Currently LLVM does not define the MSVC builtins _CountLeadingZeros and _CountLeadingZeros64 when targeting ARM/ARM64. This forces us to maintain a parallel code path in <bit> for LLVM targeting ARM.
We should make a bug/feature request asking the LLVM devs to implement these builtins when targeting ARM/ARM64.