```C
#include <jack/jack.h>
#include <stdint.h>

jack_default_audio_sample_t read_sample32(const char* buffer) {
        int32_t s = (int32_t)read_le32(buffer);
        uint32_t upper_bound = s > 0 ? (uint32_t)INT32_MAX : (uint32_t)-INT32_MIN;
        return (jack_default_audio_sample_t)s / (jack_default_audio_sample_t)upper_bound;
}
```
produces:

test.c: In function ‘read_sample32’:
test.c:6:65: warning: integer overflow in expression [-Woverflow]
  uint32_t upper_bound = s > 0 ? (uint32_t)INT32_MAX : (uint32_t)-INT32_MIN;