| Issue |
120482
|
| Summary |
[AIX] Bad codegen passing packed aggregates containing PPC vectors
|
| Labels |
platform:aix
|
| Assignees |
|
| Reporter |
hubert-reinterpretcast
|
Consider (with `-DPACKED`):
```cpp
extern "C" {
struct
#if PACKED
__attribute__((__packed__))
#endif
A {
vector unsigned int x;
};
void g(void *p);
void f(unsigned long, A a) {
g(&a);
}
}
```
As a packed structure, arguments of type `A` should be passed without special treatment for 16-byte alignment (https://www.ibm.com/docs/en/aix/7.3?topic=sequence-argument-passing); however, the 16-byte alignment behaviour is observed whether `-DPACKED` is specified or not.
Online compiler link: https://godbolt.org/z/314ddxcb7
Compiler invocation command:
```
clang++ --target=powerpc64-ibm-aix -DPACKED -O -S -o - -emit-llvm packedvecpassing.cc
```
Actual output (partial):
```
define void @f(i64 noundef %0, ptr noundef byval(%struct.A) align 16 %a) local_unnamed_addr #0 {
```
Expected output (partial):
```
define void @f(i64 noundef %0, ptr noundef byval(%struct.A) align 8 %a) local_unnamed_addr #0 {
```
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