[Openmp-commits] [openmp] [clang-tidy] Add performance-move-smart-pointer-contents check. (PR #66139)
Congcong Cai via Openmp-commits
openmp-commits at lists.llvm.org
Tue Sep 12 18:39:13 PDT 2023
https://github.com/HerrCai0907 requested changes to this pull request.
This check has some issue in my opinion, the semantic of `std::move(*p)` are not same as `*std::move(p)`
```c++
#include <iostream>
#include <memory>
#include <string>
using std::unique_ptr;
void f1() {
unique_ptr<std::string> p{new std::string("demo")};
std::cout << p.get() << " *p=" << *p << "\n";
auto x = std::move(*p);
std::cout << p.get() << " *p=" << *p << " x=" << x << "\n";
}
void f2() {
unique_ptr<std::string> p{new std::string("demo")};
std::cout << p.get() << " *p=" << *p << "\n";
auto x = *std::move(p);
std::cout << p.get() << " *p=" << *p << " x=" << x << "\n";
}
int main() {
std::cout << "std::move(*p)\n";
f1();
std::cout << "*std::move(p)\n";
f2();
}
```
The output is
```
std::move(*p)
0x603000001b40 *p=demo
0x603000001b40 *p= x=demo
*std::move(p)
0x603000001b70 *p=demo
0x603000001b70 *p=demo x=demo
```
In `*std::move(p)`, move constructor does not happen, it is same as *p.
https://github.com/llvm/llvm-project/pull/66139
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