[CIR] Implement cir.int type and attribute

[sitio-couto]

Replaces the usage of the building integer types by a dialect-specific integer with arbitrary size and signedness. Since building integer attributes requires builtin integer types, a cir.int attribute was also created.

[bcardosolopes]

I really like this, good work Vinicius.

It would also probably be interesting if we add aliases as part of this, so we don't need to do all these changes again. I was thinking for instance !cir.int<s32> could be just !s32 (or !si32?), and so on a so forth.

I also believe we can make it more terse without losing meaning, like:
!cir.int<s, 32> -> cir.int<s32>
!cir.int<u, 16> -> cir.int<u16>, ...
(For parsing that you could use llvm::StringSwitch).

wdyt?

[bcardosolopes]

Regarding tests:

• Add a test/CIR/IR/int.cir test, listing a good set of variations of types and attributes.
• Add a few malformed / unsupported types in test/CIR/IR/invalid.cir that exercise the verifiers or asm parser. Example: !cir.int<s, 42>.

[sitio-couto]

I also believe we can make it more terse without losing meaning, like:
!cir.int<s, 32> -> cir.int
!cir.int<u, 16> -> cir.int, ...
(For parsing that you could use llvm::StringSwitch).

@bcardosolopes regarding this review ☝️

It would look good on the IR, but not so much on the code. Having a keyword switch for parsing arbitrary integer types seems a bit cumbersome and contradictory. Since the type aliases already fix the "looks" matter, I would rather leave this as-is so we get a bit of a cleaner code.

Let me know what you think.

[bcardosolopes]

Since the type aliases already fix the "looks" matter

Good point, we don't need two "terse" representations!

Let me know what you think.

Sounds good to leave as is and handle on the alias

[bcardosolopes]

Overall looks great, pending the existence of one last mlir::IntegerAttr I've found. Two follow ups:

• Move this out from draft so I can approve.
• Mark conversations you've tackled as "resolved" (in general for other PRs too - since it removes some noise)

[bcardosolopes]

I already moved it out of Draft, but there are some remaining conflicts, feel free to rebase and merge when you fix them.