[Bug tree-optimization/72785] [7 Regression] kernel build error since r236831

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72785

--- Comment #4 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
(In reply to Jeffrey A. Law from comment #3)
> If someone has a .i file for this issue, it'd be awful handy.

Well, see comment0:

markus@x4 linux % cat timekeeping.i
int a, b;
extern int ____ilog2_NaN(void);
void by(void) {
  int c = 1;
  b = a ?: c;
  __builtin_constant_p(b) ? b ? ____ilog2_NaN() : 0 : 0;
}