* [Bug middle-end/93181] [9/10/11 Regression] -Wuninitialized fails to warn about uninitialized value
[not found] <bug-93181-4@http.gcc.gnu.org/bugzilla/>
@ 2021-04-07 20:29 ` msebor at gcc dot gnu.org
2021-04-08 14:25 ` rguenth at gcc dot gnu.org
` (5 subsequent siblings)
6 siblings, 0 replies; 7+ messages in thread
From: msebor at gcc dot gnu.org @ 2021-04-07 20:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93181
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|-Wuninitialized fails to |[9/10/11 Regression]
|warn about uninitialized |-Wuninitialized fails to
|value; |warn about uninitialized
|-Wmaybe-uninitialized |value
|should also warn. |
CC| |msebor at gcc dot gnu.org
Last reconfirmed|2020-01-21 00:00:00 |2021-4-7
Known to fail| |10.2.0, 11.0, 9.2.0
--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> ---
Reconfirmed with GCC 11. The warning ceased to be issued between r120372 and
r120373 so it's technically a regression.
With optimization the warning sees the IL below. Both arguments of the p_3 PHI
that it considers are valid so it has nothing to complain about.
void ub_express (int x)
{
struct foo * p;
int _1;
int _2;
<bb 2> [local count: 1073741824]:
if (x_4(D) == 2)
goto <bb 5>; [34.00%]
else
goto <bb 3>; [66.00%]
<bb 5> [local count: 365072224]:
goto <bb 4>; [100.00%]
<bb 3> [local count: 708669600]:
<bb 4> [local count: 1073741824]:
# p_3 = PHI <&a(3), &b(5)>
# VUSE <.MEM_6(D)>
_1 = p_3->count;
_2 = _1 + 1;
# .MEM_7 = VDEF <.MEM_6(D)>
p_3->count = _2;
# VUSE <.MEM_7>
return;
}
Without optimization the IL (below) does have a PHI with an uninitialized
operand so it could warn then, but it doesn't consider PHI nodes then.
Considering PHIs in the simplest cases (to avoid false positives) also when
-Wuninitialized runs early, without optimization, would make it possible to
detect this bug.
void ub_express (int x)
{
struct foo * p;
int _1;
int _2;
<bb 2> :
if (x_5(D) == 1)
goto <bb 3>; [INV]
else
goto <bb 4>; [INV]
<bb 3> :
p_7 = &a;
<bb 4> :
# p_3 = PHI <p_6(D)(2), p_7(3)>
if (x_5(D) == 2)
goto <bb 5>; [INV]
else
goto <bb 6>; [INV]
<bb 5> :
p_8 = &b;
<bb 6> :
# p_4 = PHI <p_3(4), p_8(5)>
# VUSE <.MEM_9(D)>
_1 = p_4->count;
_2 = _1 + 1;
# .MEM_10 = VDEF <.MEM_9(D)>
p_4->count = _2;
# VUSE <.MEM_10>
return;
}
^ permalink raw reply [flat|nested] 7+ messages in thread* [Bug middle-end/93181] [9/10/11 Regression] -Wuninitialized fails to warn about uninitialized value
[not found] <bug-93181-4@http.gcc.gnu.org/bugzilla/>
2021-04-07 20:29 ` [Bug middle-end/93181] [9/10/11 Regression] -Wuninitialized fails to warn about uninitialized value msebor at gcc dot gnu.org
@ 2021-04-08 14:25 ` rguenth at gcc dot gnu.org
2021-04-30 7:56 ` [Bug middle-end/93181] [9/10/11/12 " rguenth at gcc dot gnu.org
` (4 subsequent siblings)
6 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-04-08 14:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93181
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |9.4
^ permalink raw reply [flat|nested] 7+ messages in thread* [Bug middle-end/93181] [9/10/11/12 Regression] -Wuninitialized fails to warn about uninitialized value
[not found] <bug-93181-4@http.gcc.gnu.org/bugzilla/>
2021-04-07 20:29 ` [Bug middle-end/93181] [9/10/11 Regression] -Wuninitialized fails to warn about uninitialized value msebor at gcc dot gnu.org
2021-04-08 14:25 ` rguenth at gcc dot gnu.org
@ 2021-04-30 7:56 ` rguenth at gcc dot gnu.org
2021-06-01 8:15 ` rguenth at gcc dot gnu.org
` (3 subsequent siblings)
6 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-04-30 7:56 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93181
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P2
^ permalink raw reply [flat|nested] 7+ messages in thread* [Bug middle-end/93181] [9/10/11/12 Regression] -Wuninitialized fails to warn about uninitialized value
[not found] <bug-93181-4@http.gcc.gnu.org/bugzilla/>
` (2 preceding siblings ...)
2021-04-30 7:56 ` [Bug middle-end/93181] [9/10/11/12 " rguenth at gcc dot gnu.org
@ 2021-06-01 8:15 ` rguenth at gcc dot gnu.org
2022-05-27 9:41 ` [Bug middle-end/93181] [10/11/12/13 " rguenth at gcc dot gnu.org
` (2 subsequent siblings)
6 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-06-01 8:15 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93181
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|9.4 |9.5
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 9.4 is being released, retargeting bugs to GCC 9.5.
^ permalink raw reply [flat|nested] 7+ messages in thread* [Bug middle-end/93181] [10/11/12/13 Regression] -Wuninitialized fails to warn about uninitialized value
[not found] <bug-93181-4@http.gcc.gnu.org/bugzilla/>
` (3 preceding siblings ...)
2021-06-01 8:15 ` rguenth at gcc dot gnu.org
@ 2022-05-27 9:41 ` rguenth at gcc dot gnu.org
2022-06-28 10:39 ` jakub at gcc dot gnu.org
2023-07-07 10:36 ` [Bug middle-end/93181] [11/12/13/14 " rguenth at gcc dot gnu.org
6 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-05-27 9:41 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93181
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|9.5 |10.4
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 9 branch is being closed
^ permalink raw reply [flat|nested] 7+ messages in thread* [Bug middle-end/93181] [10/11/12/13 Regression] -Wuninitialized fails to warn about uninitialized value
[not found] <bug-93181-4@http.gcc.gnu.org/bugzilla/>
` (4 preceding siblings ...)
2022-05-27 9:41 ` [Bug middle-end/93181] [10/11/12/13 " rguenth at gcc dot gnu.org
@ 2022-06-28 10:39 ` jakub at gcc dot gnu.org
2023-07-07 10:36 ` [Bug middle-end/93181] [11/12/13/14 " rguenth at gcc dot gnu.org
6 siblings, 0 replies; 7+ messages in thread
From: jakub at gcc dot gnu.org @ 2022-06-28 10:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93181
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|10.4 |10.5
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 10.4 is being released, retargeting bugs to GCC 10.5.
^ permalink raw reply [flat|nested] 7+ messages in thread* [Bug middle-end/93181] [11/12/13/14 Regression] -Wuninitialized fails to warn about uninitialized value
[not found] <bug-93181-4@http.gcc.gnu.org/bugzilla/>
` (5 preceding siblings ...)
2022-06-28 10:39 ` jakub at gcc dot gnu.org
@ 2023-07-07 10:36 ` rguenth at gcc dot gnu.org
6 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2023-07-07 10:36 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93181
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|10.5 |11.5
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 10 branch is being closed.
^ permalink raw reply [flat|nested] 7+ messages in thread