This is 2nd patch in series following the RFC http://lists.llvm.org/pipermail/cfe-dev/2019-March/061834.html informing the community about providing CMSE support in clang/llvm.
This is patch L 1 (as mentioned in the RFC). Previous patch:
C1: [ARM][CMSE] Add commandline option and feature macro https://reviews.llvm.org/D59879
It defines the intrinsics cmse_TT, cmse_TTT, cmse_TTA, cmse_TTAT. There is no tests here as the tests are in subsequent clang patch that uses these intrinsics .