[Bug c/30368] missing warning for dereferencing null pointer

[egallager at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30368

Eric Gallager  changed:

   What|Removed |Added

   See Also||https://gcc.gnu.org/bugzill
   ||a/show_bug.cgi?id=16351

--- Comment #10 from Eric Gallager  ---
(In reply to Jeffrey A. Law from comment #8)
> The plan for 16351 would be to catch in gimple-ssa-isolate-paths.c, but that
> won't catch this instance because of the wrapping ADDR_EXPR.
> 
> Regardless, while related, this is not, IMHO a dup of 16351

putting it under "See Also" then

[Bug c/30368] missing warning for dereferencing null pointer

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30368

Martin Sebor  changed:

   What|Removed |Added

   Keywords||diagnostic
 CC||msebor at gcc dot gnu.org
   Last reconfirmed|2007-03-13 16:12:46 |2020-5-18

--- Comment #9 from Martin Sebor  ---
Missing warning reconfirmed with GCC 11.

The last pass where the null pointer is still available is the CCP1 pass whose
output shows that it removes it:

$ gcc -O2 -S -Wall -Wextra -fdump-tree-ccp1-all=/dev/stdout pr30368.c

...
Substituting values and folding statements

Folding statement: _1 = _3->b;
Folded into: _1 = 0B;

Folding statement: if (_1 != 0B)
...

So it should be possible to diagnose the dereference there, just prior to its
removal.

[Bug c/30368] missing warning for dereferencing null pointer

[law at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30368

Jeffrey A. Law law at redhat dot com changed:

   What|Removed |Added

 Status|RESOLVED|NEW
 CC||law at redhat dot com
 Resolution|DUPLICATE   |---

--- Comment #8 from Jeffrey A. Law law at redhat dot com ---
The plan for 16351 would be to catch in gimple-ssa-isolate-paths.c, but that
won't catch this instance because of the wrapping ADDR_EXPR.

Regardless, while related, this is not, IMHO a dup of 16351

[Bug c/30368] missing warning for dereferencing null pointer

[manu at gcc dot gnu dot org]

--- Comment #6 from manu at gcc dot gnu dot org  2007-03-13 16:12 ---
So the conclusion is that we should emit a warning for the undefinedness.


-- 

manu at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
 Ever Confirmed|0   |1
   Last reconfirmed|-00-00 00:00:00 |2007-03-13 16:12:46
   date||
Summary|wrong result|missing warning for
   ||dereferencing null pointer


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30368

[Bug c/30368] missing warning for dereferencing null pointer

[manu at gcc dot gnu dot org]

--- Comment #7 from manu at gcc dot gnu dot org  2007-03-13 16:22 ---
and as such, this is a duplicate of bug 16351.

*** This bug has been marked as a duplicate of 16351 ***


-- 

manu at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution||DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30368