[Bug tree-optimization/107838] spurious "may be used uninitialized" warning on variable initialized at the first iteration of a loop

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107838

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think there's a duplicate bug, we fail to pick up the controlling condition
because IVOPTs replaced the exit test but we still have

  i_19 = (int) ivtmp.4_6;
  if (i_19 == 0)

...

  <bb 7> [local count: 966367643]:
  ivtmp.4_21 = ivtmp.4_6 + 1;
  if (ivtmp.4_21 != 9)

thus with -fno-ivopts the predication code works fine.  It doesn't try
hard enough to consider "derived" conditions like the above.