<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/86057>86057</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [x86_32][clang] Empty structure argument are ignored in function variable arguments.
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          CoTinker
      </td>
    </tr>
</table>

<pre>
    demo.cpp
```
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

struct S2210 {} ;
struct S2210 s2210;
void check2210va (int z, ...) {
    struct S2210 arg;
    va_list ap;
    __builtin_va_start(ap, z);
    arg = __builtin_va_arg(ap, struct S2210);
    long double a = __builtin_va_arg(ap, long double);
    printf("%Lf\n", a);
    if (a != 2.0L)
       printf("Fail\n");
 __builtin_va_end(ap);
}
int main (void) {
    check2210va (2, s2210, 2.0L);
}
```
compile command:
```
% clang++ demo.cpp -m32
% ./a.out
```
clang:
```
0.000000
Fail
```
gcc:
```
2.000000
```
https://godbolt.org/z/EqWa5nq13
</pre>
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