    1. store_src_rg                   coords = src.rg
    2. init_lane_masks                CondMask = LoopMask = RetMask = true
    3. zero_slot_unmasked             x(0) = 0
    4. copy_constant                  x(1) = 0x3F800000 (1.0)
    5. copy_constant                  x(2) = 0x40000000 (2.0)
    6. copy_constant                  x(3) = 0x40400000 (3.0)
    7. copy_2_slots_unmasked          y = x(0..1)
    8. copy_2_slots_unmasked          $0..1 = y
    9. zero_slot_unmasked             $2 = 0
   10. copy_constant                  $3 = 0x3F800000 (1.0)
   11. load_src                       src.rgba = $0..3