refine vbroadcast jitcode

test=develop

paddle/fluid/operators/jit/gen/vbroadcast.cc

@@ -37,36 +37,33 @@ void VBroadcastJitCode::genCode() {
   }
 
   // protect param_h
-  const size_t width_in_byte = sizeof(float) * w_;
   mov(reg_height, param_h);
-  int acc_num_regs = 0;
-  for (int num_regs : groups) {
+  Label l_next_h;
+  xor_(reg_h_i, reg_h_i);
+  mov(reg_ptr_dst_i, param_dst);
+  L(l_next_h);
+  {
     mov(reg_ptr_src_i, param_src);
-    add(reg_ptr_src_i, acc_num_regs * block_size);
+    for (int num_regs : groups) {
       size_t w_offset = 0;
       for (int reg_i = 0; reg_i < num_regs; ++reg_i) {
         vmovups(ymm_t(reg_i), ptr[reg_ptr_src_i + w_offset]);
         w_offset += block_size;
       }
+      add(reg_ptr_src_i, num_regs * block_size);
 
-    Label l_next_h;
-    xor_(reg_h_i, reg_h_i);
-    mov(reg_ptr_dst_i, param_dst);
-    add(reg_ptr_dst_i, acc_num_regs * block_size);
-    L(l_next_h);
-    {
       w_offset = 0;
       for (int reg_i = 0; reg_i < num_regs; ++reg_i) {
         vmovups(ptr[reg_ptr_dst_i + w_offset], ymm_t(reg_i));
         w_offset += block_size;
       }
-      add(reg_ptr_dst_i, width_in_byte);
+      add(reg_ptr_dst_i, num_regs * block_size);
+    }  // end of groups
     inc(reg_h_i);
     cmp(reg_h_i, reg_height);
     jl(l_next_h, T_NEAR);
   }  // end of l_next_h
-    acc_num_regs += num_regs;
-  }  // end of groups
+
   postCode();
 }