[mypyc] Refactor mypyc.ir.ops: replace LoadInt with Integer (#9859)
The new class is a direct subclass of `Value` instead of an `Op` subclass.
It essentially changes integers from operations to literals.
The main benefit is that IR generation is a bit easier, as `Integer` instances
no longer must be added to a basic block. We can also get rid of some special
treatment of `LoadInt` in IR pretty printing and C generation.
Liveness analysis and some other analyses may also become faster, since
they don't need to track the lifetimes of integers, and there are fewer ops for
which data flow information needs to be calculated. Integers no longer have
interesting lifetimes, since they are treated as "pure values" and always directly
associated with the `Op` that uses them. I couldn't measure a performance
improvement, however, so the impact may be negligible or non-existent.
This may also make some IR optimizations slightly easier to implement.
Work on mypyc/mypyc#781.
mypy
3c99f126 - [mypyc] Refactor mypyc.ir.ops: replace LoadInt with Integer (#9859)
