remove unused code test=develop (#22327)

paddle/fluid/operators/sum_op.cu

@@ -67,22 +67,6 @@ __global__ void SumSelectedRowsCUDAKernel(T **sr_in_out, int64_t N,
   }
 }
 
-template <class T>
-__global__ void SumAlign4CUDAKernel(const T *in_0, const T *in_1, T *out,
-                                    int64_t N) {
-  int id = blockIdx.x * blockDim.x + threadIdx.x;
-  for (int i = id; i < N / 4; i += blockDim.x * gridDim.x) {
-    const float4 *in0_4 = reinterpret_cast<float4 *>(in_0);
-    const float4 *in1_4 = reinterpret_cast<float4 *>(in_1);
-    float4 tmp;
-    tmp.x = in0_4[i].x + in1_4[i].x;
-    tmp.y = in0_4[i].y + in1_4[i].y;
-    tmp.z = in0_4[i].z + in1_4[i].z;
-    tmp.w = in0_4[i].w + in1_4[i].w;
-    reinterpret_cast<float4 *>(out)[i] = tmp;
-  }
-}
-
 template <class T>
 void SumToLoDTensor(const framework::ExecutionContext &context) {
   auto in_vars = context.MultiInputVar("X");