| Issue |
89581
|
| Summary |
[x86] llvm #pragma pack behaviour is different from gcc
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
zhangtianhao6
|
hello, I use #pragma pack(1) to change the ExampleStruct member align and print the address of ExampleStruct, the ExampleStruct address printed by the gcc compiler is 8-byte aligned, but the ExampleStruct address printed by the llvm compiler is 1-byte aligned. why they are different, which is correct?
```
#include <iostream>
#include <mutex>
#pragma pack(1)
struct ExampleStruct {
std::mutex mutex_;
int b;
};
#pragma pack()
ExampleStruct example;
int main(){
std::cout << &example << std::endl;
std::cout << alignof(example) << std::endl;
}
```
```
result:
gcc print: 0x404160
llvm print: 0x555d1805f031
```
godbolt demo:
https://godbolt.org/z/Yv7Taxfqa
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