message: core:vsx fix build failure on GCC<=6 due implementation of v_reduce_sum(v_float64x2)
diff: @@ -718,7 +718,7 @@ OPENCV_HAL_IMPL_VSX_REDUCE_OP_4(v_float32x4, vec_float4, float, min, vec_min)
  inline double v_reduce_sum(const v_float64x2& a)
  {
  - return vec_extract(vec_add(a.val, vec_sld(a.val, a.val, 8)), 0);
  + return vec_extract(vec_add(a.val, vec_permi(a.val, a.val, 3)), 0);
  }
  #define OPENCV_HAL_IMPL_VSX_REDUCE_OP_8(_Tpvec, _Tpvec2, scalartype, suffix, func) \
  