alt Hacker NewsYes, unaligned loads/stores are a niche feature that has huge implications in processor design - loads across cache-lines with different residency, pages that fault etc.
This is the classic conundrum of legacy system redesign - if customers keep demanding every feature of the old system be present, and work the exact same then the new system will take on the baggage it was designed to get rid of.
The new implementation will be slow and buggy by this standard and nobody will use it.
Unaligned load/store is crucial for zero-copy handling of mmaped data, network streams and all other kinds of space-optimized data structures.
If the CPU doesn't do it software must make many tiny conditional copies which is bad for branch prediction.
This sucks double when you have variable length vector operations... IMO fast unaligned memory accesses should have been mandatory without exceptions for all application-level profiles and everything with vector.