In e838f27e0f3 the EndianTest.cpp unittest was updated to avoid using
`llvm::rotl` function, but the corresponding `orc_rt::rotl` function had
not been implemented yet.
This commit implements orc_rt::rotl, orc_rt::rotr, and
orc_rt::has_single_bit by copying their definitions from the
corresponding LLVM header (llvm-project/llvm/include/llvm/ADT/bit.h).
Unit tests for these functions are also copied from their LLVM
counterparts.
Thanks to @jaredwy for spotting this!
The unit test was copied from a similar test in llvm, and was still
qualifying calls with 'llvm::'. This was unintended, but happened to
work because LLVM's bit.h is transitively included through LLVM's gtest
headers. Qualifying with 'orc_rt::' tests the intended functions.
Thanks to @jaredwy for spotting this!
The 64-bit path included references to the llvm:: namespace that would
have caused compile failures but for the fact that they were compiled
out on all machines where the ORC runtime is currently tested.
