Celegans12 9513703244 fix(shader): read the half-wave scans of wave64 reductions on any host subgroup ...

The GFX10 lowering of a wave64 reduction scans rows with DPP row_shr
1/2/4/8 and v_permlanex16_b32 under EXEC -1, then joins lanes 31 and 63
with a scalar op. The console fills lanes outside the entry EXEC with
the identity, but on the host they can be helpers that sit out subgroup
operations or invocations that were never launched: on 64 lanes (RADV)
the emulated chain reads 0 or stale values from them, and on 32 lanes
lane 63 throws since #997.

EmitReadLane now recognises the sequence on any host for UMin, UMax,
SMin, SMax, IAdd, AND and OR when the keys are the identity outside the
entry EXEC. On 64 lanes, lanes 31 and 63 become subgroup reductions of
the keys of invocations 0-31 and 32-63; on 32 lanes or fewer, lane 31
reduces all keys and lane 63 is the identity. It throws without
subgroup arithmetic or on a subgroup wider than the wave. VulkanDevice
reports GroupNonUniformArithmetic and ShaderValidation checks it.

2026-10-08 12:10:32 +02:00

..

ARCHITECTURE.md

docs: add architecture overview with Mermaid diagrams

2026-10-04 11:20:38 +02:00

BUILD.md

Merge pull request #1083 from ctz23/docs/linux-x11-build-requirements-20261007

2026-10-08 18:29:03 +13:00

CONVENTIONS.md

refactor(docs): separated user and dev in docs + compatibility file

2026-09-28 22:58:17 +03:00

HW_ORACLE.md

fix(oracle)!: require explicit float modes

2026-10-07 14:58:28 +05:00

PROGRESS.md

fix(progress): report shared-source libraries

2026-10-07 21:40:38 +02:00

TechnicalDebt.md

fix(shader): read the half-wave scans of wave64 reductions on any host subgroup

2026-10-08 12:10:32 +02:00