Comment by ashton314

2 years ago

You misunderstand. If I, at the assembly level, could express things like "this register ranges from 0 to 4"—I might be able to provide ever-lower levels of the stack with more information about my intent. Maybe the ISA can now do something clever to further optimize my program. Now, there will likely always be a time when all types are erased, but if we can push that erasure lower and lower in the stack, then compilers have more and more information about what we actually want them to do, provided our type systems are rich enough to express that intent.

2 comments

ashton314

Reply
almostgotcaught  2 years ago

> "this register ranges from 0 to 4"

that's not a type system, that's an ILP. and we already have that in many compilers (bindings to ILP solvers).

> Maybe the ISA can now do something clever to further optimize my program.

this is a malformed sentence - the ISA is fixed and isn't making any gametime decisions about your code (modulo branch prediction/cache-fretching). it's all in the compiler and like i said we already have this in many many compilers and it's surfaced in various ways (eg trip count on loops).