Since the C compiler can hide that, for core kernel code I think the more problematic thing was Alpha's memory consistency model where (data-)dependent loads accesses did not imply ordering, which is unusual and more burdensome to the programmer than any other ISA.

That required this smp_read_barrier_depends() through the kernel, but actually in recent years that has basically been subsumed by other concurrent access primitives that all the core kernel must use, so I think alpha is no longer much of a problem outside arch/alpha