https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81281
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
void
foo (unsigned p, unsigned a, unsigned b)
{
unsigned q = p + 7;
if (a - (1U + __INT_MAX__) >= 2)
__builtin_unreachable ();
int d = p + b;
int c = p + a;
if (c - d != __INT_MAX__)
__builtin_abort ();
}
void
bar (unsigned p, unsigned a)
{
unsigned q = p + 7;
if (a - (1U + __INT_MAX__) >= 2)
__builtin_unreachable ();
int c = p;
int d = p + a;
if (c - d != -__INT_MAX__ - 1)
__builtin_abort ();
}
int
main ()
{
foo (-1U, 1U + __INT_MAX__, 1U);
bar (-1U, 1U + __INT_MAX__);
return 0;
}
is a testcase that fails on the trunk with -O2 because of this (without any
sanitization).
On the other side, when add is a plus and not pointer_plus, the pattern doesn't
contain :c as I found when writing the testcase, so it matches only if the
SSA_NAMEs are in the right order.
