0c7c82af23
Add AtomGroup and AtomRank to DILocation behind compile time flag EXPERIMENTAL_KEY_INSTRUCTIONS which is controlled by cmake flag LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS. Add IR read-write roundtrip test in a directory that is unsupported unless the CMake flag is enabled. RFC: https://discourse.llvm.org/t/rfc-improving-is-stmt-placement-for-better-interactive-debugging/82668