APS5_SPANNED_WAVE is now read once by the driver, which sets
SpirvTarget::spannedWaves only on a device with 32-lane compute subgroup
control and computeFullSubgroups. The recompiler no longer reads the
environment. The field is part of the cache key and of the request
serialization (version 32), so a cached or replayed module keeps the mode
it was built in.
A spanned module numbers its lanes SubgroupId * 32 +
SubgroupLocalInvocationId, which needs two full 32-lane subgroups. The
artifact records this as fullSubgroups (disk cache and pipeline identity
included), and the driver creates those pipelines with
REQUIRE_FULL_SUBGROUPS. Compute pipeline captures accept the flag with a
required subgroup size.
The two-lane fallback now catches only SpannedWaveUnsupported, thrown for
a shuffle wider than 32 bits; other emit errors surface as before.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
