[Bug tree-optimization/88441] missing warning on a buffer overflow with non-constant offset and constant size

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88441

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |10.0
   Target Milestone|---                         |10.0
      Known to fail|                            |9.3.0
         Resolution|---                         |FIXED
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Thanks to r279392 GCC 10 detects the certain overflow in g:

pr88441.c: In function ‘g’:
pr88441.c:13:5: warning: writing 8 bytes into a region of size 7
[-Wstringop-overflow=]
   13 |     __builtin_memcpy (a + i, p, sizeof a);   // missing
-Wstringop-overflow
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pr88441.c:1:6: note: at offset 0 to object ‘a’ with size 8 declared here
    1 | char a[8];
      |      ^

It feels like a separate question whether the possible/likely overflow should
also be diagnosed when it's not certain.  Diagnosing it would be a design
change for the overflow warnings that are currently meant to trigger for
certain overflows, so I'm going to resolve this as fixed.