[llvm-branch-commits] [LowerAllowCheck] Add llvm.allow.sanitize.* intrinsics (PR #172029)

[Marco Elver via llvm-branch-commits]

https://github.com/melver created https://github.com/llvm/llvm-project/pull/172029

Add new intrinsics:
  - llvm.allow.sanitize.address
  - llvm.allow.sanitize.thread
  - llvm.allow.sanitize.memory
  - llvm.allow.sanitize.hwaddress

These intrinsics return true if the corresponding sanitizer is enabled
for the function, and false otherwise. They are lowered by
LowerAllowCheckPass to constant booleans based on the corresponding
sanitize_* function attributes.

LowerAllowCheckPass is now "required" to run on functions with optnone
to ensure correct lowering at O0.