https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108808
Bug ID: 108808
Summary: G++ -O2 incorrectly bypasses an infinite loop
Product: gcc
Version: 12.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: zhihan.yue at foxmail dot com
Target Milestone: ---
Compile the following code with G++ -O2:
#include <string>
#include <iostream>
struct Test {
bool a = false;
std::string b;
};
int main() {
Test test;
test.a = false;
std::cout << "enter" << std::endl;
while(! test.a);
std::cout << "passed" << std::endl;
return 0;
}
Executing the program, the output will be:
enter
passed
This shows that the infinite loop was skipped.
Tested versions: (x64)
- Problem happens on GCC V10.1-10.4, V11.1-11.3, V12.1-12.2
- No such problem on GCC V9.5, V8.5, V7.5
Seems like a bug introduced in V10.1
