Constant evaluation wrong right-shift result for 32-bit LHS

[fuhsnn]

#include <stdio.h>
int main(void) {
  printf("%d\n", ({ char a[ 3U << 31 >> 31 ]; sizeof(a); })); // expect 1, got 3
  printf("%d\n", ({ char a[ 1 << 31 >> 31 ]; sizeof(a); })); // expect -1, got 1
}