------- Comment #10 from rguenth at gcc dot gnu dot org 2010-05-28 17:51
-------
(In reply to comment #9)
> Okay. What if we stick with equality operators, then?
>
> static inline void
> foo(int *p)
> {
> if (p == a + 1 || p == a + 2) {
> p[-1] = 0;
> }
> }
>
> This code results in the same warning.
Yep. That's because a and b might not bind locally and thus we do not
know whether &b[0] == &a[1].
We don't warn for -fno-common, but in this case we might still
optimize the comparison.
Confirmed for the testcase in comment #9.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rguenth at gcc dot gnu dot
| |org
Status|UNCONFIRMED |NEW
Component|c |middle-end
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2010-05-28 17:51:52
date| |
Summary|Spurious array subscript |Spurious array subscript
|warning |warning, &b[0] == &a[1] is
| |not folded
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44300
