fix pooling3x3s2 max. test=develop (#4419)

lite/backends/arm/math/pooling.cc

@@ -2224,7 +2224,13 @@ void pooling3x3s2p1_max(const float* din,
     w_unroll_size -= 1;
     w_unroll_remian = wout - w_unroll_size * 4;
   }
-  float32x4_t vmin = vdupq_n_f32(std::numeric_limits<float>::lowest());
+  int w_needed = wout * 2 + 1;
+  int need_right = w_needed - win - pad_right;
+  int w_2 = need_right > 0 ? w_unroll_remian : w_unroll_remian + 1;
+  w_2 = w_unroll_size <= 0 ? w_2 - 1 : w_2;
+  need_right = wout > 1 ? need_right : 0;
+  float minval = std::numeric_limits<float>::lowest();
+  float32x4_t vmin = vdupq_n_f32(minval);
 
   for (int n = 0; n < num; ++n) {
     float* data_out_batch = data_out + n * chout * size_channel_out;
@@ -2263,6 +2269,11 @@ void pooling3x3s2p1_max(const float* din,
               break;
           }
         }
+
+        auto pr0 = dr0;
+        auto pr1 = dr1;
+        auto pr2 = dr2;
+
         int cnt_num = w_unroll_size;
         if (w_unroll_size > 0) {
 #ifdef __aarch64__
@@ -2316,27 +2327,60 @@ void pooling3x3s2p1_max(const float* din,
                 "q11",
                 "q15");
 #endif
+
           dr0 -= 8;
           dr1 -= 8;
           dr2 -= 8;
-        }
-        // deal with right pad
-        int wstart = w_unroll_size * 4 * S - P;
-        for (int j = 0; j < w_unroll_remian; ++j) {
-          int wend = std::min(wstart + K, win);
-          int st = wstart > 0 ? wstart : 0;
-          float tmp = dr0[0];
-          for (int i = 0; i < wend - st; i++) {
+        } else {
+          float tmp = minval;
+          int left_ = std::min(2, win);
+          for (int i = 0; i < left_; i++) {
             tmp = std::max(tmp, dr0[i]);
             tmp = std::max(tmp, dr1[i]);
             tmp = std::max(tmp, dr2[i]);
           }
-          *(dr_out++) = tmp;
-          dr0 += S - (st - wstart);
-          dr1 += S - (st - wstart);
-          dr2 += S - (st - wstart);
-          wstart += S;
+
+          dr_out[0] = tmp;
+          dr0++;
+          dr1++;
+          dr2++;
+          dr_out++;
         }
+
+        for (int w = 0; w < w_2 - 1; w += 1) {
+          float32x4_t vr0 = vld1q_f32(dr0);
+          float32x4_t vr1 = vld1q_f32(dr1);
+          float32x4_t vr2 = vld1q_f32(dr2);
+          vr0 = vsetq_lane_f32(minval, vr0, 3);
+          vr1 = vsetq_lane_f32(minval, vr1, 3);
+          vr2 = vsetq_lane_f32(minval, vr2, 3);
+          float32x4_t vmax1 = vmaxq_f32(vr0, vr1);
+          vmax1 = vmaxq_f32(vmax1, vr2);
+          float32x2_t vmax2 =
+              vpmax_f32(vget_low_f32(vmax1), vget_high_f32(vmax1));
+          float32x2_t vmax = vpmax_f32(vmax2, vmax2);
+          dr_out[0] = vget_lane_f32(vmax, 0);
+          dr_out++;
+
+          dr0 += 2;
+          dr1 += 2;
+          dr2 += 2;
+        }
+
+        if (need_right) {
+          float tmp = minval;
+          int idx = win - 1;
+          tmp = std::max(tmp, std::max(pr0[idx], pr1[idx]));
+          tmp = std::max(tmp, pr2[idx]);
+          dr_out[0] = tmp;
+          if (win % 2) {
+            idx = win - 2;
+            tmp = std::max(tmp, std::max(pr0[idx], pr1[idx]));
+            tmp = std::max(tmp, pr2[idx]);
+            dr_out[0] = tmp;
+          }
+        }
+
         data_out_channel += wout;
       }
     }
@@ -2573,6 +2617,7 @@ void pooling3x3s2p0_max(const float* din,
   int wend = std::min(tmp_val + K, win) - tmp_val;
   float minval = std::numeric_limits<float>::lowest();
   remain = right > 0 ? remain : remain + 1;
+
   for (int n = 0; n < num; ++n) {
     float* data_out_batch = data_out + n * chout * size_channel_out;
     const float* data_in_batch = data_in + n * chin * size_channel_in;
@@ -2663,13 +2708,14 @@ void pooling3x3s2p0_max(const float* din,
               vpmax_f32(vget_low_f32(vmax1), vget_high_f32(vmax1));
           float32x2_t vmax = vpmax_f32(vmax2, vmax2);
           dr_out[0] = vget_lane_f32(vmax, 0);
+
           dr_out++;
           dr0 += 2;
           dr1 += 2;
           dr2 += 2;
         }
-        if (right) {
-          float tmp = dr0[0];  // std::numeric_limits<float>::min();
+        if (right > 0) {
+          float tmp = dr0[0];
           for (int i = 0; i < wend; i++) {
             tmp = std::max(tmp, std::max(dr0[i], dr1[i]));
             tmp = std::max(tmp, dr2[i]);