A BDA dword read whose span the probe rejects falls back to four byte
lookups with a branch each, and every fault was recorded inline with a
compare-exchange and seven stores. Both were copied into every read
site and both wave64 lane halves, so one large compute program grows
to about a million SPIR-V words and spends about 95 s in
vkCreateComputePipelines.
Faults are now recorded by one DontInline function, record_bda_fault,
and the byte fallback of a dword is read_bda_dword_bytes, in a stop
and a coherent variant, returning the value and whether the invocation
stops. Read order, fault reasons, pcs, Volatile and the stop behaviour
are unchanged, and so is the probe path.
Celegans12
boykopovar