* [Bug middle-end/104965] [11/12 Regression] Yet another -Warray-bounds false positive
2022-03-17 12:15 [Bug middle-end/104965] New: Yet another -Warray-bounds false positive redi at gcc dot gnu.org
@ 2022-03-17 12:52 ` rguenth at gcc dot gnu.org
2022-03-17 13:47 ` redi at gcc dot gnu.org
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From: rguenth at gcc dot gnu.org @ 2022-03-17 12:52 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104965
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |11.3
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Likely a similar issue as PR104966, avoid relying on memory CSE across a call
to 'new'.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/104965] [11/12 Regression] Yet another -Warray-bounds false positive
2022-03-17 12:15 [Bug middle-end/104965] New: Yet another -Warray-bounds false positive redi at gcc dot gnu.org
2022-03-17 12:52 ` [Bug middle-end/104965] [11/12 Regression] " rguenth at gcc dot gnu.org
@ 2022-03-17 13:47 ` redi at gcc dot gnu.org
2022-03-17 16:00 ` msebor at gcc dot gnu.org
` (6 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: redi at gcc dot gnu.org @ 2022-03-17 13:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104965
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
In this case s.size() reads a local variable that can't be altered by new.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/104965] [11/12 Regression] Yet another -Warray-bounds false positive
2022-03-17 12:15 [Bug middle-end/104965] New: Yet another -Warray-bounds false positive redi at gcc dot gnu.org
2022-03-17 12:52 ` [Bug middle-end/104965] [11/12 Regression] " rguenth at gcc dot gnu.org
2022-03-17 13:47 ` redi at gcc dot gnu.org
@ 2022-03-17 16:00 ` msebor at gcc dot gnu.org
2022-03-17 23:46 ` pinskia at gcc dot gnu.org
` (5 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: msebor at gcc dot gnu.org @ 2022-03-17 16:00 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104965
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |msebor at gcc dot gnu.org
--- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> ---
It looks like an escape analysis limitation. With this simpler test case using
different types to rule out aliasing assumptions:
#include <string>
int main()
{
std::basic_string<short> s;
auto p = new int[s.size ()]{ };
char c = 0;
if (s.size())
c = *p;
delete[] p;
return c;
}
pr104965.C:9:9: warning: array subscript 0 is outside array bounds of ‘void
[0]’ [-Warray-bounds]
9 | c = *p;
| ^~
pr104965.C:6:34: note: object of size 0 allocated by ‘operator new []’
6 | auto p = new short[s.size ()]{ };
| ^
One of the stores to the local s escapes its address which is then assumed to
have been clobbered by operator new:
<bb 2> [local count: 1073741824]:
s ={v} {CLOBBER};
MEM[(struct _Alloc_hider *)&s] ={v} {CLOBBER};
MEM[(struct _Alloc_hider *)&s]._M_p = &s.D.33279._M_local_buf;
s._M_string_length = 0;
MEM[(char_type &)&s + 16] = 0;
_5 = operator new [] (0);
<bb 3> [local count: 1073741824]:
_10 = s._M_string_length;
if (_10 != 0)
goto <bb 4>; [50.00%]
else
goto <bb 5>; [50.00%]
<bb 4> [local count: 536870913]:
_1 = MEM[(int *)_5];
c_6 = (char) _1;
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/104965] [11/12 Regression] Yet another -Warray-bounds false positive
2022-03-17 12:15 [Bug middle-end/104965] New: Yet another -Warray-bounds false positive redi at gcc dot gnu.org
` (2 preceding siblings ...)
2022-03-17 16:00 ` msebor at gcc dot gnu.org
@ 2022-03-17 23:46 ` pinskia at gcc dot gnu.org
2022-04-21 7:51 ` rguenth at gcc dot gnu.org
` (4 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-03-17 23:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104965
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I think the missed optimization is recorded as either PR 79349 or PR 103827.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/104965] [11/12 Regression] Yet another -Warray-bounds false positive
2022-03-17 12:15 [Bug middle-end/104965] New: Yet another -Warray-bounds false positive redi at gcc dot gnu.org
` (3 preceding siblings ...)
2022-03-17 23:46 ` pinskia at gcc dot gnu.org
@ 2022-04-21 7:51 ` rguenth at gcc dot gnu.org
2022-07-26 12:41 ` [Bug middle-end/104965] [11/12/13 " rguenth at gcc dot gnu.org
` (3 subsequent siblings)
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From: rguenth at gcc dot gnu.org @ 2022-04-21 7:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104965
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|11.3 |11.4
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 11.3 is being released, retargeting bugs to GCC 11.4.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/104965] [11/12/13 Regression] Yet another -Warray-bounds false positive
2022-03-17 12:15 [Bug middle-end/104965] New: Yet another -Warray-bounds false positive redi at gcc dot gnu.org
` (4 preceding siblings ...)
2022-04-21 7:51 ` rguenth at gcc dot gnu.org
@ 2022-07-26 12:41 ` rguenth at gcc dot gnu.org
2022-07-26 12:41 ` rguenth at gcc dot gnu.org
` (2 subsequent siblings)
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From: rguenth at gcc dot gnu.org @ 2022-07-26 12:41 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104965
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P2
Last reconfirmed| |2022-7-26
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Re-confirmed. Didn't we change libstdc++ to not expect CSE around new?
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/104965] [11/12/13 Regression] Yet another -Warray-bounds false positive
2022-03-17 12:15 [Bug middle-end/104965] New: Yet another -Warray-bounds false positive redi at gcc dot gnu.org
` (5 preceding siblings ...)
2022-07-26 12:41 ` [Bug middle-end/104965] [11/12/13 " rguenth at gcc dot gnu.org
@ 2022-07-26 12:41 ` rguenth at gcc dot gnu.org
2022-07-26 13:59 ` redi at gcc dot gnu.org
2023-05-29 10:06 ` [Bug middle-end/104965] [11/12/13/14 " jakub at gcc dot gnu.org
8 siblings, 0 replies; 10+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-07-26 12:41 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104965
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/104965] [11/12/13 Regression] Yet another -Warray-bounds false positive
2022-03-17 12:15 [Bug middle-end/104965] New: Yet another -Warray-bounds false positive redi at gcc dot gnu.org
` (6 preceding siblings ...)
2022-07-26 12:41 ` rguenth at gcc dot gnu.org
@ 2022-07-26 13:59 ` redi at gcc dot gnu.org
2023-05-29 10:06 ` [Bug middle-end/104965] [11/12/13/14 " jakub at gcc dot gnu.org
8 siblings, 0 replies; 10+ messages in thread
From: redi at gcc dot gnu.org @ 2022-07-26 13:59 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104965
--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #6)
> Re-confirmed. Didn't we change libstdc++ to not expect CSE around new?
I don't think that's valid, is it?
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/104965] [11/12/13/14 Regression] Yet another -Warray-bounds false positive
2022-03-17 12:15 [Bug middle-end/104965] New: Yet another -Warray-bounds false positive redi at gcc dot gnu.org
` (7 preceding siblings ...)
2022-07-26 13:59 ` redi at gcc dot gnu.org
@ 2023-05-29 10:06 ` jakub at gcc dot gnu.org
8 siblings, 0 replies; 10+ messages in thread
From: jakub at gcc dot gnu.org @ 2023-05-29 10:06 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104965
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|11.4 |11.5
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 11.4 is being released, retargeting bugs to GCC 11.5.
^ permalink raw reply [flat|nested] 10+ messages in thread