https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95103
Bug ID: 95103
Summary: Unexpected -Wclobbered in bits/vector.tcc with -O2
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: sbergman at redhat dot com
Target Milestone: ---
I have seen this with at least some GCC 7, and still see it with GCC 10 and
with recent trunk:
> $ cat test.cc
> #include <csetjmp>
> #include <vector>
> struct S {
> S(int);
> ~S();
> };
> void f1();
> bool f2(char const (& s)[3]) {
> for (int i = 0; i != 2; ++i) {
> if (s[i] != 'x') {
> return false;
> }
> }
> return true;
> }
> void f3() {
> std::vector<S> v;
> for (int i = 0; i != 2; ++i) {
> if (!f2("xx")) f1();
> v.push_back(0);
> }
> std::jmp_buf b;
> setjmp(b);
> }
> $ g++ -Wclobbered -O2 -c test.cc
> In file included from /usr/include/c++/10/vector:72,
> from test.cc:2:
> /usr/include/c++/10/bits/vector.tcc: In function ‘void f3()’:
> /usr/include/c++/10/bits/vector.tcc:441:15: warning: variable ‘__new_finish’
> might be clobbered by ‘longjmp’ or ‘vfork’ [-Wclobbered]
> 441 | pointer __new_finish(__new_start);
> | ^~~~~~~~~~~~
