http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60429
--- Comment #18 from Richard Biener <rguenth at gcc dot gnu.org> ---
Seems to be a PTA issue:
InsertionSort_pETEchase.29_82, points-to vars: { }
InsertionSort_pETEchase.29_86, points-to non-local, points-to escaped,
points-to vars: { }
p1_155, points-to NULL, points-to vars: { }
<bb 30>:
InsertionSort_pETEchase.29_82->next = p1_84;
p1_155->next = InsertionSort_pETEchase.28_85;
InsertionSort_pETEchase.29_86 = InsertionSort_pETEchase.28_85->back;
InsertionSort_pETEchase.29_86->next = p1_155;
p1_155->back = &InsertionSort_pETEchaseBackTMP;
taking _155 as example
# p1_155 = PHI <_35(57), p1_58(60)>
_35, points-to NULL, points-to vars: { }
p1_58, points-to vars: { }
_35 = MEM[(struct _EdgeTableEntry * *)&AET + 16B];
# p1_58 = PHI <p1_84(59), p1_84(30), p1_87(34)>
p1_84 = p1_155->next;
p1_87 = p1_155->next;
so it's a cycle seeded only by MEM[(struct _EdgeTableEntry * *)&AET + 16B];
_35 = { NULL } same as AET.128+64
_35 = AET.128+64
# p1_150 = PHI <&AET(47), p1_151(49)>
# p1_151 = PHI <p1_19(47), p1_45(49)>
p1_45 = p1_151->next;
fn3_tmp = p1_45;
p1_151->next = p1_47;
p1_151->back = p1_150;
p1_150 = &AET.0+96
*p1_150 + 128 = p1_151
Note that valgrind shows loads of errors (with the reduced testcase at least)
that show invalid reads and writes even at -O0. So we may just optimistically
optimize based on that undefined behavior.
At least I can't see anything wrong with what PTA derives ...
