Why am I not getting compiler warnings for buffer overflow with -D_FORTIFY_SOURCE=2 in gcc 10.2.0?

Question

Is there any change wrt to FORTIFY_SOURCE in gcc 10.2.0. I am not getting compiler warnings for buffer overflow during build but buffer overflow is detected during runtime and the program terminates.

I have set the flags -O2 -g -D_FORTIFY_SOURCE=2. Previously on gcc7.3, this implementation did give me the compiler warnings as well as the runtime warnings. Now I am not getting any compiler warnings and I have just updated the gcc version.

Also for information I have -Wall and -Wextra flags enabled as well.

here is my main.cpp file

#include "stdio.h"
#include "string.h"

int main(void)
{
    char var1[5];
    char var2[9];
    printf("size of var1",var1,sizeof(var1));
    strcpy(var1,"abcdefghi");
    memcpy(&var1,&var2,10);
    printf("size of var1",var1,sizeof(var1));
    return 0;


}

Have been stuck on it for days so would really appreciate some help.