dump_mir
dump MIR state to file.
val is used to select which passes and functions to dump. For example:
all matches all passes and functions,
foo matches all passes for functions whose name contains ‘foo’,
foo & ConstProp only the ‘ConstProp’ pass for function names containing ‘foo’,
foo | bar all passes for function names containing ‘foo’ or ‘bar’.
This feature has no tracking issue, and is therefore likely internal to the compiler, not being intended for general use.