I don't understand the meaning of usingless machine language code generated by compiling C language

I compiled the following C language program with clang (clang is 3.4-1ubuntu3, OS is Ubuntu Ubuntu 14.04.5 on AWS, 32bit).

sample.c

#include <stdio.h>
int func(int a, int b)
{
    return a + b;
}
int main()
{
    int x = 1;
    int y = 2;
    int c;
    c = func(x, y);
    printf("%d\n",c);
    return 0;
}

This is an excerpt of the result of disassembling the code compiled with clang with objdump -d.

objdump.s

 8048464:       89 4c 24 04             mov    %ecx,0x4(%esp)
 8048468:       e8 b3 ff ff ff          call   8048420 <func>
 804846d:       8d 0d 30 85 04 08       lea    0x8048530,%ecx
 8048473:       89 45 f0                mov    %eax,-0x10(%ebp)
 8048476:       8b 45 f0                mov    -0x10(%ebp),%eax

What I would like you to know is mov %eax,-0x10(%esp) After mov -0x10(%esp),%eax Is why you need it. The value of the eax register hasn't changed, so I feel it's unnecessary. Is there any special reason? By the way, even if I compile it with gcc, the generated code was similar. If you are an expert, I would appreciate it if you could tell me.