Possible gcc bug with setjmp()?

[Jeroen Demeyer <jdemeyer@xxxxxxxxxxxxx>]

I have some problematic code using setjmp() behaving differently from 
what I expect.  I would like to know whether it is a bug in GCC or 
whether I am somehow abusing setjmp()/longjmp().

Call the example program below jmp.c and compile with
gcc -Og jmp.c -o jmp
using GCC-4.8.0. Run the program ./jmp and the output is

Returning 1
x = 0, n = 1
Returning 0
x = 42, n = 1
Aborted

Strangely, g() is returning 0 the second time (after longjmp()) but the 
return value, assigned to n, equals 1. With other optimization levels or 
earlier versions of GCC, the output is what I expect:

Returning 1
x = 0, n = 1
Returning 0
x = 42, n = 0



/* jmp.c */

#include <stdio.h>
#include <stdlib.h>
#include <setjmp.h>

static sigjmp_buf env;

static inline int g(int x)
{
    if (x)
    {
        fprintf(stderr, "Returning 0\n");
        return 0;
    }
    else
    {
        fprintf(stderr, "Returning 1\n");
        return 1;
    }
}

int f(int *e)
{
    if (*e) return 1;

    int x = setjmp(env);
    int n = g(x);
    fprintf(stderr, "x = %i, n = %i\n", x, n);

    if (n == 0) exit(0);
    if (x) abort();
    longjmp(env, 42);
}

int main(int argc, char** argv)
{
    int v = 0;
    return f(&v);
}