https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108780
Bug ID: 108780
Summary: Spurious warning with -ftrivial-auto-var-init=zero
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: trprince at synopsys dot com
Target Milestone: ---
I encountered the following spurious (or at least, confusing/misleading--note
the variable name) warning on some code after enabling
`-ftrivial-auto-var-init=zero` on one of our codebases. It appears that there
have been similar issues with spurious warnings and
`-ftrivial-auto-var-init=zero` in the past but I was able to reproduce this
with trunk on godbolt:
https://godbolt.org/z/zre74sWq1
$ cat bad.cpp
struct a {
int b();
};
void c() {
a d;
const auto &e(d.b());
}
$ g++ --version
g++ (GCC) 12.1.0
Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ g++ -ftrivial-auto-var-init=zero -Wuninitialized -c bad.cpp
bad.cpp: In function ‘void c()’:
bad.cpp:6:22: warning: ‘D.2414’ is used uninitialized [-Wuninitialized]
6 | const auto &e(d.b());
| ^
$
I'd be happy to provide any additional context if I'm missing anything.
