如何检查两个用C语言编写的不同风格的代码是否等价？

样式一：

#include <stdio.h>
#define K1 42
#define K2 1200

int i1, i2, i3 = -10;
unsigned u1, u2 = 1230, u3 = K1, u4;

int main( void ) {
    
    scanf( "%d", &i2 );
    scanf( "%u", &u1 );
    for ( i1 = i2 - 1; i2 < i3-i1 || u2 >= u1; u2 = u3, u3 = u3 % ++u4 ) {
        i2 = i2 / 2 + i3++;
        scanf( "%u", &u4 );
        do {
            i3 -= K2;
            u4 = ( u4 << 2 ) & ~ 0x04;
            i1 = i3 / i2;
        } while ( u4 < K1 && i1 + 23 >= i2 + 4 );
        u3 = --u1 + ( u4 -= 2);
    }
    u1 = ( u4 - u2 ) * 5 + ( u2 + u3 ) / 6 - u1;
    
    return 0;
}

样式二：

#include <stdio.h>
#define K1 42
#define K2 1200

int i1 = 0;
int i2 = 0;
int i3 = -10;
int t;
unsigned u1 = 0;
unsigned u2 = 1230;
unsigned u3 = K1;
unsigned u4 = 0 ;

int main(){

    scanf( "%d", &i2 );
    scanf( "%d", &u1 );
    i1 = i2 - 1;
    t = i3 - i1;
    
for_beg:
    if ( i2 < t ) goto for_tt;
    if ( u2 >= u1 ) goto for_tt;
    goto for_ff;

for_tt:
    i2 = i2 / 2;
    i2 += i3;
    i3 += 1;
    scanf( "%u", &u4 );
    
do_begin:
    i3 -= K2;
    u4 = u4 << 2;
    u4 = ~ 0x04;
    i1 = i3 / i2;
    
while_beg:
    if ( u4 >= K1 ) goto while_ff;
    t = i1 + 23;
    int t2 = i2 + 4;
    if ( t < t2 ) goto while_ff;
    goto do_begin;
    
while_ff:
    u1 -= 1;
    u4 -= 2;
    u3 = u1 + u4;

for_end:
    u4 += 1;
    u3 %= u4;
    goto for_beg;
    
for_ff:
    t = u4 - u2;
    t2 = u2 + u3;
    t *= 5;
    t2 /= 6;
    t += t2;
    t -= u1;
    
    return 0;
}

不止是逐行验证代码，我应该使用调试工具吗？谢谢你，谢谢！
我尝试执行打印u1变量的代码，但代码仍在循环中