https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96511
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Known to fail| |10.2.0, 11.0, 8.4.0, 9.3.0
Status|UNCONFIRMED |NEW
Last reconfirmed| |2020-08-07
CC| |msebor at gcc dot gnu.org
--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Confirmed. To determine the final offset the warning multiplies the offset in
a POINTER_PLUS expression by the elements size the same way it does the index
in an ARRAY_REF expression. The latter is correct but the former isn't.
A simplified test case:
$ cat pr96511.C && gcc -S -Wall -Wextra pr96511.C
void* operator new (__SIZE_TYPE__, void *p) { return p; }
void g ()
{
int a[2];
new (&a[0] + 1) int;
}
pr96511.C: In function ‘void g()’:
pr96511.C:7:14: warning: placement new constructing an object of type ‘int’ and
size ‘4’ in a region of type ‘int [2]’ and size ‘0’ [-Wplacement-new=]
7 | new (&a[0] + 1) int;
| ~~~~~~^~~
