https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102248
Bug ID: 102248
Summary: -Wstringop-overflow false positive
Product: gcc
Version: 10.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: eugene.chereshnev at intel dot com
Target Milestone: ---
Created attachment 51428
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51428&action=edit
Preprocessed file
Observing false positive with 10.x versions, 9.x and 11.x versions are good.
Reproduced only with -O3.
$ g++ --version
g++ (GCC) 10.3.0
Copyright (C) 2020 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.
$ cat 1.cpp
#include <cstdint>
struct Foo {
int8_t a, b;
Foo(): a(0), b(1) {}
};
struct Bar {
Bar();
Foo x0;
Foo x1;
Foo x2;
Foo x3;
};
void foo(Foo&);
Bar::Bar() { foo(x0); }
$ g++ -c -O3 1.cpp
In constructor ‘Foo::Foo()’,
inlined from ‘Bar::Bar()’ at 1.cpp:21:10:
1.cpp:6:21: warning: writing 8 bytes into a region of size 2
[-Wstringop-overflow=]
6 | Foo(): a(0), b(1) {}
| ^
1.cpp: In constructor ‘Bar::Bar()’:
1.cpp:12:9: note: at offset 0 to object ‘Bar::x0’ with size 2 declared here
12 | Foo x0;
| ^~
Godbolt link: https://godbolt.org/z/W7e4PqK7n
