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* [Bug middle-end/103637] New: [12 Regression] missing warning writing past the end of one of multiple elements of the same array
@ 2021-12-09 19:46 msebor at gcc dot gnu.org
2021-12-10 0:31 ` [Bug middle-end/103637] " pinskia at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: msebor at gcc dot gnu.org @ 2021-12-09 19:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103637
Bug ID: 103637
Summary: [12 Regression] missing warning writing past the end
of one of multiple elements of the same array
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
The fix for pr103215 is too conservative and causes false negatives for past
the end accesses to array elements like in gcc.dg/warn-strnlen-no-nul.c. A
simple test case that shows the problem is below. The dump shows that both
strcpy calls are plainly out of bounds and both could and should be diagnosed.
$ cat y.c && gcc -O2 -S -Wall -fdump-tree-optimized=/dev/stdout y.c
extern int x;
extern char b[5][7];
void f (const char *s)
{
__builtin_strncpy (b[3], s, 9); // warning (good)
}
void g (int i, const char *s)
{
char *d = i ? b[3] : b[4];
__builtin_strncpy (d, s, 9); // warning in GCC 11, missing in 12
}
;; Function f (f, funcdef_no=0, decl_uid=1980, cgraph_uid=1, symbol_order=0)
void f (const char * s)
{
<bb 2> [local count: 1073741824]:
__builtin_strncpy (&b[3], s_2(D), 9); [tail call]
return;
}
y.c: In function ‘f’:
y.c:7:3: warning: ‘__builtin_strncpy’ writing 9 bytes into a region of size 7
overflows the destination [-Wstringop-overflow=]
7 | __builtin_strncpy (b[3], s, 9); // warning (good)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
y.c:3:13: note: at offset 21 into destination object ‘b’ of size 28
3 | extern char b[5][7];
| ^
;; Function g (g, funcdef_no=1, decl_uid=1984, cgraph_uid=2, symbol_order=1)
Removing basic block 3
void g (int i, const char * s)
{
char * iftmp.0_1;
<bb 2> [local count: 1073741824]:
if (i_2(D) != 0)
goto <bb 4>; [50.00%]
else
goto <bb 3>; [50.00%]
<bb 3> [local count: 536870912]:
<bb 4> [local count: 1073741824]:
# iftmp.0_1 = PHI <&b[3](2), &b[4](3)>
__builtin_strncpy (iftmp.0_1, s_4(D), 9); [tail call]
return;
}
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/103637] [12 Regression] missing warning writing past the end of one of multiple elements of the same array
2021-12-09 19:46 [Bug middle-end/103637] New: [12 Regression] missing warning writing past the end of one of multiple elements of the same array msebor at gcc dot gnu.org
@ 2021-12-10 0:31 ` pinskia at gcc dot gnu.org
2022-05-06 8:32 ` [Bug middle-end/103637] [12/13 " jakub at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-10 0:31 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103637
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |12.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/103637] [12/13 Regression] missing warning writing past the end of one of multiple elements of the same array
2021-12-09 19:46 [Bug middle-end/103637] New: [12 Regression] missing warning writing past the end of one of multiple elements of the same array msebor at gcc dot gnu.org
2021-12-10 0:31 ` [Bug middle-end/103637] " pinskia at gcc dot gnu.org
@ 2022-05-06 8:32 ` jakub at gcc dot gnu.org
2023-02-21 15:01 ` rguenth at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2022-05-06 8:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103637
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|12.0 |12.2
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 12.1 is being released, retargeting bugs to GCC 12.2.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/103637] [12/13 Regression] missing warning writing past the end of one of multiple elements of the same array
2021-12-09 19:46 [Bug middle-end/103637] New: [12 Regression] missing warning writing past the end of one of multiple elements of the same array msebor at gcc dot gnu.org
2021-12-10 0:31 ` [Bug middle-end/103637] " pinskia at gcc dot gnu.org
2022-05-06 8:32 ` [Bug middle-end/103637] [12/13 " jakub at gcc dot gnu.org
@ 2023-02-21 15:01 ` rguenth at gcc dot gnu.org
2023-04-14 4:53 ` law at gcc dot gnu.org
2023-05-08 12:23 ` [Bug middle-end/103637] [12/13/14 " rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2023-02-21 15:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103637
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Known to fail| |13.0
Last reconfirmed| |2023-02-21
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed on trunk.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/103637] [12/13 Regression] missing warning writing past the end of one of multiple elements of the same array
2021-12-09 19:46 [Bug middle-end/103637] New: [12 Regression] missing warning writing past the end of one of multiple elements of the same array msebor at gcc dot gnu.org
` (2 preceding siblings ...)
2023-02-21 15:01 ` rguenth at gcc dot gnu.org
@ 2023-04-14 4:53 ` law at gcc dot gnu.org
2023-05-08 12:23 ` [Bug middle-end/103637] [12/13/14 " rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: law at gcc dot gnu.org @ 2023-04-14 4:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103637
Jeffrey A. Law <law at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P2
CC| |law at gcc dot gnu.org
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/103637] [12/13/14 Regression] missing warning writing past the end of one of multiple elements of the same array
2021-12-09 19:46 [Bug middle-end/103637] New: [12 Regression] missing warning writing past the end of one of multiple elements of the same array msebor at gcc dot gnu.org
` (3 preceding siblings ...)
2023-04-14 4:53 ` law at gcc dot gnu.org
@ 2023-05-08 12:23 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2023-05-08 12:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103637
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|12.3 |12.4
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 12.3 is being released, retargeting bugs to GCC 12.4.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-05-08 12:23 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2021-12-09 19:46 [Bug middle-end/103637] New: [12 Regression] missing warning writing past the end of one of multiple elements of the same array msebor at gcc dot gnu.org
2021-12-10 0:31 ` [Bug middle-end/103637] " pinskia at gcc dot gnu.org
2022-05-06 8:32 ` [Bug middle-end/103637] [12/13 " jakub at gcc dot gnu.org
2023-02-21 15:01 ` rguenth at gcc dot gnu.org
2023-04-14 4:53 ` law at gcc dot gnu.org
2023-05-08 12:23 ` [Bug middle-end/103637] [12/13/14 " rguenth at gcc dot gnu.org
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