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; echo $?
8
$
$ icc -O3 small.c; ./a.out; echo $?
9
$
$ cat small.c
struct
{
unsigned char f0;
} a, *b = &a, c, *e = &c;
int d, f;
int main ()
{
for (f = 0; f < 2; f++)
a.f0 = 0;
for (; a.f0 != 8; a.f0 = (unsigned) a.f0 + 9)
while (d)
;
*e = *b;
return c.f0;
}
$