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* [Bug tree-optimization/110896] New: [12/13/14 Regression] gcc.dg/ubsan/pr81981.c is xfailed
@ 2023-08-03 22:46 pinskia at gcc dot gnu.org
2023-08-03 22:47 ` [Bug tree-optimization/110896] " pinskia at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-08-03 22:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110896
Bug ID: 110896
Summary: [12/13/14 Regression] gcc.dg/ubsan/pr81981.c is
xfailed
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Keywords: diagnostic, xfail
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Blocks: 24639
Target Milestone: ---
The original issue in PR 81981 is fixed. The problem here is we don't even warn
without -fsanitize=undefined too.
Testcase from that PR:
```
int foo (int i)
{
int t[1], u[1];
int n = 0;
if (i)
{
t[n] = i;
u[0] = i;
}
return t[0] + u[0];
}
```
we don't warn about `u[0]` being unintinialized with just `-O2 -Wall -Wextra`
starting in GCC 12 via r12-4625 (the fix for pr102681). That is the issue is
unrelated to -fsanitize=undefined now.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=24639
[Bug 24639] [meta-bug] bug to track all Wuninitialized issues
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/110896] [12/13/14 Regression] gcc.dg/ubsan/pr81981.c is xfailed
2023-08-03 22:46 [Bug tree-optimization/110896] New: [12/13/14 Regression] gcc.dg/ubsan/pr81981.c is xfailed pinskia at gcc dot gnu.org
@ 2023-08-03 22:47 ` pinskia at gcc dot gnu.org
2023-08-04 7:07 ` rguenth at gcc dot gnu.org
2024-03-07 23:26 ` law at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-08-03 22:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110896
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |12.4
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/110896] [12/13/14 Regression] gcc.dg/ubsan/pr81981.c is xfailed
2023-08-03 22:46 [Bug tree-optimization/110896] New: [12/13/14 Regression] gcc.dg/ubsan/pr81981.c is xfailed pinskia at gcc dot gnu.org
2023-08-03 22:47 ` [Bug tree-optimization/110896] " pinskia at gcc dot gnu.org
@ 2023-08-04 7:07 ` rguenth at gcc dot gnu.org
2024-03-07 23:26 ` law at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2023-08-04 7:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110896
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Last reconfirmed| |2023-08-04
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
We simplify this to t[0] * 2 (by luck, so it could also be u[0] * 2) which
means we lose track of the use of the other variable.
Value numbering stmt = t$0_4 = PHI <t$0_13(D)(2), t$0_15(3)>
Setting value number of t$0_4 to t$0_4 (changed)
Making available beyond BB4 t$0_4 for value t$0_4
Value numbering stmt = u$0_12 = PHI <u$0_14(D)(2), u$0_16(3)>
Marking CSEd to PHI node t$0_4 = PHI <t$0_13(D)(2), t$0_15(3)>
Setting value number of u$0_12 to t$0_4 (changed)
...
Replaced redundant PHI node defining u$0_12 with t$0_4
gimple_simplified to _9 = t$0_4 * 2;
early uninit sees conditional init of the memory and so refrains from
diagnosing this.
I suppose this is kind-of a duplicate of the many missed uninit diagnostics
because of CCP optimistic propagation (and only because we don't do optimistic
copyprop we do not have even more such cases).
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/110896] [12/13/14 Regression] gcc.dg/ubsan/pr81981.c is xfailed
2023-08-03 22:46 [Bug tree-optimization/110896] New: [12/13/14 Regression] gcc.dg/ubsan/pr81981.c is xfailed pinskia at gcc dot gnu.org
2023-08-03 22:47 ` [Bug tree-optimization/110896] " pinskia at gcc dot gnu.org
2023-08-04 7:07 ` rguenth at gcc dot gnu.org
@ 2024-03-07 23:26 ` law at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: law at gcc dot gnu.org @ 2024-03-07 23:26 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110896
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] 4+ messages in thread
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2023-08-03 22:46 [Bug tree-optimization/110896] New: [12/13/14 Regression] gcc.dg/ubsan/pr81981.c is xfailed pinskia at gcc dot gnu.org
2023-08-03 22:47 ` [Bug tree-optimization/110896] " pinskia at gcc dot gnu.org
2023-08-04 7:07 ` rguenth at gcc dot gnu.org
2024-03-07 23:26 ` law at gcc dot gnu.org
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