| Issue |
146973
|
| Summary |
[aarch64][win] Applying alignment to a stack object causes a mis-compilation when using exception on Arm64 Windows
|
| Labels |
backend:AArch64,
platform:windows
|
| Assignees |
|
| Reporter |
dpaoliello
|
Given the following code:
```cpp
// Large object: alignment seems to be important?
struct alignas(128) BigObj {
int value;
// Destructor so it's kept alive.
~BigObj() { }
};
// Exception type need to be large enough to not fit in a register.
struct Error {
int value;
int padding[3];
};
int main() {
BigObj bo{};
try {
throw Error { 42, {0, 0, 0} };
} catch (const Error& e) {
return e.value;
}
return 0;
}
```
This program crashes when built and run on Arm64 Windows:
```pwsh
> & 'C:\Program Files\LLVM\bin\clang.exe' .\test.cpp
> .\a.exe
> $LASTEXITCODE
-1073741819
```
The `alignas` seems to be important: if I remove that and replace it with a very large array within `BigObj` then the issue no longer reproduces.
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