------- Comment #1 from rguenth at gcc dot gnu dot org 2007-11-27 11:30 -------
Runtime testcase:
int __attribute__((noinline)) GetParent(void)
{
static int count = 0;
count++;
switch (count)
{
case 1:
case 3:
case 4:
return 1;
default:
return 0;
}
}
int __attribute__((noinline)) FindCommonAncestor(int aNode1, int aNode2)
{
if (aNode1 && aNode2) {
int offset = 0;
int anc1 = aNode1;
for (;;) {
++offset;
int parent = GetParent();
if (!parent)
break;
anc1 = parent;
}
int anc2 = aNode2;
for (;;) {
--offset;
int parent = GetParent();
if (!parent)
break;
anc2 = parent;
}
if (anc1 == anc2) {
anc1 = aNode1;
anc2 = aNode2;
while (offset > 0) {
anc1 = GetParent();
--offset;
}
while (offset < 0) {
anc2 = GetParent();
++offset;
}
while (anc1 != anc2) {
anc1 = GetParent();
anc2 = GetParent();
}
return anc1;
}
}
return 0;
}
extern void abort (void);
int main()
{
if (FindCommonAncestor (1, 1) != 0)
abort ();
return 0;
}
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34244
