[SPIR-V] Bugs when write to out vertices in mesh shader

[CgGraphic]

when compiling mesh shader code like this into spir_v, it fails to write to gl_Position, producing black image

void MSMain(    
    uint dtid : SV_DispatchThreadID,
    uint gtid : SV_GroupThreadID,
    uint gid : SV_GroupID,
    uint tig : SV_GroupIndex,
    in payload TaskPayload s_Payload,
    out vertices VSOutput verts[MAX_VERTEX_NUM],
    out indices uint3 tris[MAX_PRIMITIVE_NUM])
{
      verts[local_thread_id].Pos= transformtoNDC(position);
      GroupMemoryBarrier();
       /* some calculation read from verts[local_thread_id].Pos*/
       GroupMemoryBarrier();
      verts[local_thread_id] = doStuff ( verts[local_thread_id].SV_POSITION);
}

the compiled code, captured from NSight, create a temp param_var_verts, but failed to write to it

    uint _152[32] = in_var_meshLetId;
    uint _158 = _152[gl_WorkGroupID.x];
    MeshletInfo _160 = ce_MeshLetInfos._m0[_158];
    uint _166 = (_160.mVertexCount + 31u) / 32u;
    VSOutput param_var_verts[64];

   ....
   
     uint _210 = ((_202 * cbMesh.ce_VertexStride) + uint(cbMesh.ce_PositionOffset.x)) >> 2u;
     vec4 _233 = ((vec4(uintBitsToFloat(uvec3(ce_Vertices._m0[_210], ce_Vertices._m0[_210 + 1u], ce_Vertices._m0[_210 + 2u])), 1.0) * cbModel.ce_World) * cbPassMeta.ce_View) * cbPassMeta.ce_Projection;
     vec4 _236 = _233;
     _236.y = -_233.y;
      gl_out[_175].gl_Position = _236;
    // nevery write to param_var_verts, but read from 
     float _242 = -param_var_verts[_175].Pos.w;
     ndcVertexCullBits[_175] = ((((((0u | uint(param_var_verts[_175].Pos.x < _242)) | ((param_var_verts[_175].Pos.x > param_var_verts[_175].Pos.w) ? 2u : 0u)) | ((param_var_verts[_175].Pos.y < _242) ? 4u : 0u)) | ((param_var_verts[_175].Pos.y > param_var_verts[_175].Pos.w) ? 8u : 0u)) | ((param_var_verts[_175].Pos.z < 0.0) ? 16u : 0u)) | ((param_var_verts[_175].Pos.z > param_var_verts[_175].Pos.w) ? 32u : 0u)) | ((param_var_verts[_175].Pos.w <= 0.0) ? 64u : 0u);
            local_to_global[_175] = _202;
     GroupMemoryBarrier();
    // read from param_var_verts[_175].Pos.w
    GroupMemoryBarrier();
    // read from param_var_verts[_175].Pos.w
     gl_out[_388].gl_Position = param_var_verts[_388].Pos;

[kuhar]

Thanks for reporting, @CgGraphic. Would you be able to provide a minimal reproducer with all the definitions necessary to compile it, together with your full compiler invocation command?

[sudonatalie]

Without a sample that we can compile this issue isn't feasible to reproduce. Closing this issue for now but we'd be happy to re-open it if complete repro steps are provided.