https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111536
Bug ID: 111536
Summary: -fanalyzer false positive with NRVO return
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: analyzer
Assignee: dmalcolm at gcc dot gnu.org
Reporter: ibuclaw at gdcproject dot org
Target Milestone: ---
This code (translated from D to C++):
---
struct Guard {
int i;
~Guard() {}
};
Guard lock() {
return Guard();
}
void bar() {
auto foo = lock();
}
---
Produces this warning with -fanalyzer.
---
nrvo.cc: In function ‘Guard lock()’:
nrvo.cc:6:18: warning: use of uninitialized value ‘<unknown>’ [CWE-457]
[-Wanalyzer-use-of-uninitialized-value]
6 | return Guard();
| ^
‘Guard lock()’: events 1-3
|
| 5 | Guard lock() {
| | ^~~~~
| | |
| | (1) region created on stack here
| | (2) capacity: 8 bytes
| 6 | return Guard();
| | ~
| | |
| | (3) use of uninitialized value ‘<unknown>’ here
|
nrvo.cc:6:18: warning: use of uninitialized value ‘<unknown>’ [CWE-457]
[-Wanalyzer-use-of-uninitialized-value]
6 | return Guard();
| ^
‘void bar()’: events 1-2
|
| 8 | void bar() {
| | ^~~
| | |
| | (1) entry to ‘bar’
| 9 | auto foo = lock();
| | ~
| | |
| | (2) calling ‘lock’ from ‘bar’
|
+--> ‘Guard lock()’: events 3-6
|
| 5 | Guard lock() {
| | ~~~~~ ^~~~
| | | |
| | | (3) entry to ‘lock’
| | (4) region created on stack here
| | (5) capacity: 8 bytes
| 6 | return Guard();
| | ~
| | |
| | (6) use of uninitialized value ‘<unknown>’
here
|
---
This is the GIMPLE representation.
---
struct Guard lock ()
{
<retval>->a = 0;
return <retval>;
}
void bar ()
{
struct Guard foo;
try
{
foo = lock (); [return slot optimization]
try
{
}
finally
{
Guard::~Guard (&foo);
}
}
finally
{
foo = {CLOBBER(eol)};
}
}
---
