Matthew Craven authored Mar 09, 2024 and Marge Bot committed Mar 19, 2024

Don't use bigNatFromWord#, because that's terrible:
 * We shouldn't have to traverse a linked list at run-time
   to build a BigNat# literal. That's just silly!
 * The static List object we have to create is much larger
   than the actual BigNat#'s contents, bloating code size.
 * We have to read the corresponding interface file,
   which causes un-tracked implicit dependencies. (#23942)

Instead, encode them into the appropriate platform-dependent
sequence of bytes, and generate code that copies these bytes
at run-time from an Addr# literal into a new ByteArray#.
A ByteArray# literal would be the correct thing to generate,
but these are not yet supported; see also #17747.

Somewhat surprisingly, this change results in a slight
reduction in compiler allocations, averaging around 0.5%
on ghc's compiler performance tests, including when compiling
programs that contain no bignum literals to begin with.
The specific cause of this has not been investigated.

Since ...