Most compilers do not use "unit" tests per se. Much more common are integration tests targeted at a particular lowering phase or optimization pass. This is pre

Most compilers do not use "unit" tests per se. Much more common are integration tests targeted at a particular lowering phase or optimization pass. This is pretty important since "unit tests" would be far too constraining for reasonable modifications to the compiler, e.g. adding a new pass could change the actual output code without modifying the semantics.