Just for the record, see also this comment from D82370:
Additionally, remove pattern for selects with 64-bit
inputs, which are rare, because handling them properly
requires more thought.
This reverted part of D81925, which originally added both 32- and 64-bit patterns.
In fact, we found that 64-bit select is not rare, partially due to the use of 64-bit pointers (tend to be uniform in most cases.) This patch is developed to address that pending issue in D81925.
Thanks for working on this!
The observation I made about 64-bit inputs being rare was based on graphics content. The changes I did in D81925 in si-fix-sgpr-copies did not universally work for 64-bit selects, so I removed that part in D82370.