Compiler version and platform:
Intel(R) C Intel(R) 64 Compiler for applications running on Intel(R) 64, Version 17.0.1.132 Build 20161005
$ icc -O2 small.c; ./a.out
0
$
$ icc -O3 small.c; ./a.out
-1
$
$ cat small.c
int printf (const char *, ...);
int a, b, c, d = 1, e, f;
void foo ()
{
for (c = 0; c < 2; c++)
{
if (d)
{
if (a && e)
continue;
b = c;
c = b;
}
break;
}
}
int main ()
{
foo ();
printf ("%d\n", c);
for (f = 0; f < 2; f++)
;
return 0;
}
$