b11876

vulkan : one warp tile per subgroup in the small matmul tiles (#30106)

WM of the small tiles was 32, or 8 for 8-wide subgroups, whatever the
tile's BLOCK_SIZE and WARP. With 16-wide subgroups (Mali) the second
subgroup of a workgroup wrote into the next tile's columns. With 8-wide
subgroups some _id tiles left rows uncomputed. Derive WM so there is one
warp tile per subgroup.

Tested on my Pixel 9 Android phone. Before the change there were 20
MUL_MAT and 6 MUL_MAT_ID failures. After the change they all pass.

Fixes #28637

Assisted-by: Claude Opus 5.5

Website:

• https://llama.app

Attestations:

• https://github.com/ggml-org/llama.cpp/attestations/59631087

macOS/iOS:

• macOS Apple Silicon (arm64)
• macOS Apple Silicon (arm64, KleidiAI enabled) DISABLED
• macOS Intel (x64)
• iOS XCFramework

Linux:

• Ubuntu x64 (CPU)
• Ubuntu arm64 (CPU)
• Ubuntu s390x (CPU)
• Ubuntu x64 (Vulkan)
• Ubuntu arm64 (Vulkan)
• Ubuntu x64 (CUDA 12) - CUDA 12.8 libraries
• Ubuntu x64 (CUDA 13) - CUDA 13.4 libraries
• Ubuntu arm64 (CUDA 13) - CUDA 13.4 libraries
• Ubuntu x64 (ROCm 10.0)
• Ubuntu x64 (OpenVINO)
• Ubuntu x64 (SYCL FP32)
• Ubuntu x64 (SYCL FP16)
• Linux arm64 (Snapdragon: CPU, Adreno GPU, Hexagon NPU) - setup guide

Android:

• Android arm64 (CPU)
• Android arm64 (Snapdragon: CPU, Adreno GPU, Hexagon NPU) - setup guide

Windows:

• Windows x64 (CPU)
• Windows arm64 (CPU)
• Windows arm64 (OpenCL Adreno)
• Windows x64 (CUDA 12) - CUDA 12.4 DLLs
• Windows x64 (CUDA 13) - CUDA 13.4 DLLs
• Windows arm64 (CUDA 13) - CUDA 13.4 DLLs
• Windows x64 (Vulkan)
• Windows arm64 (Vulkan)
• Windows x64 (OpenVINO)
• Windows x64 (SYCL)
• Windows x64 (ROCm 10.0)

openEuler:

• DISABLED
• openEuler x86 (310p)
• openEuler x86 (910b, ACL Graph)
• openEuler aarch64 (310p)
• openEuler aarch64 (910b, ACL Graph)

UI:

• UI