Function moe_router_gemm_rt 

pub fn moe_router_gemm_rt(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    input: DevicePtr,
    weight: &DenseWeight,
    output: DevicePtr,
    m: u32,
    n: u32,
    k: u32,
    stream: u64,
) -> Result<()>

2026-09-28: dense_gemm_router on 64x128 tiles with a 4x8 register tile per thread (kernel moe_router_gemm_rt, kernels/gb10/common/moe_router_gemm_prefill.cu): the same per-output FP32 accumulation in ascending k, so the same bits. Needs k % 16 == 0.