By far, one of the most common things to check for is whether or not a
value is zero, as it typically allows folding away unnecesary
operations (other close contenders that can help with eliding operations are 1 and -1).
So instead of requiring a check for an immediate and then actually
retrieving the integral value and checking it, we can wrap it within a
function to make it more convenient.
This is useful when we wish to know if a contained value is something
like 0xFFFFFFFF, as this helps perform constant folding. For example the
operation: x & 0xFFFFFFFF can be folded to just x in the 32-bit case.
This'll make it slightly nicer to do basic constant folding for 32-bit
and 64-bit variants of the same IR opcode type. By that, I mean it's
possible to inspect immediate values without a bunch of conditional
checks beforehand to verify that it's possible to call GetU32() or
GetU64, etc.
enum classes are still considered complete types when forward declared
(as the compiler knows the exact size of the type from the declaration
alone). The only difference in this case being that the members of the
enum class aren't visible. Given we don't use the members within this
header in any way, we can simply forward declare them here and remove
the inclusions.
ARM's Architecture Specification Language doesn't distinguish between floats and integers
as much as we do. This makes some things difficult to implement. Since our register
allocator is now capable of allocating values to XMMs and GPRs as necessary, the
Transfer IR instructions are no longer necessary as they used to be and they can be
removed.
