Signed overflow / unsigned wrap-around

I've recently read this:
https://lwn.net/ml/linux-kernel/20240122235208.work.748-kees@kernel.org/

Trying to experiment a bit with what I learned:

    $ cat wrapme.c
    #include <stdint.h>
    #include <err.h>
    #include <stdlib.h>
    #include <stdio.h>
    #include <limits.h>

    int main(int argc, char **argv)
    {
        int val, ival;

        if (argc < 2)
            errx(1, "Usage: %s VALUE", argv[0]);

        val = INT_MAX;
        ival = atoi(argv[1]); // feeling lazy today.

        printf("will it overflow?\n");
        if (val + ival < val)
            printf("It will overflow\n");
        else
            printf("It won't overflow\n");

        val += ival;
        printf("%d\n", val);
        return 0;
    }

Compiled with different options...

    $ make
    gcc -o ftrapv -ftrapv wrapme.c
    gcc -o fwrapv -fwrapv wrapme.c
    gcc -o default wrapme.c

How will it behave upon signed integer overflow?

    $ ./fwrapv 0
    will it overflow?
    It won't overflow
    2147483647

    $ ./fwrapv 1
    will it overflow?
    It will overflow
    -2147483648

    $ ./ftrapv 0
    will it overflow?
    It won't overflow
    2147483647

    $ ./ftrapv 1
    will it overflow?
    Aborted (core dumped)

    $ ./default 0
    will it overflow?
    It won't overflow
    2147483647

    $ ./default 1
    will it overflow?
    It won't overflow
    -2147483648