Jaro Reinders authored Jun 01, 2023 and Marge Bot committed Jul 05, 2023

In #22010 we established that Int was not always sufficient to store all
the uniques we generate during compilation on 32-bit platforms. This
commit addresses that problem by using Word64 instead of Int for
uniques.

The core of the change is in GHC.Core.Types.Unique and
GHC.Core.Types.Unique.Supply. However, the representation of uniques is
used in many other places, so those needed changes too. Additionally, the RTS
has been extended with an atomic_inc64 operation.

One major change from this commit is the introduction of the Word64Set and
Word64Map data types. These are adapted versions of IntSet and IntMap
from the containers package. These are planned to be upstreamed in the
future.

As a natural consequence of these changes, the compiler will be a bit
slower and take more space on 32-bit platforms. Our CI tests indicate
around a 5% residency increase.

Metric Increase:
    CoOpt_Read
    CoOpt_Singletons
    LargeRecord
    ManyAlternatives
    ManyConstru...