[Bug c/84873] [7/8 Regression] ICE: verify_ssa failed (error: definition in block 3 does not dominate use in block 4)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84873

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code,
                   |                            |wrong-code
          Component|tree-optimization           |c

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Note GCC 6 generated wrong code instead:

i1 (int w3, int n9)
{
  int D.1760;
  unsigned int iftmp.0;
  double D.1764;
  long int D.1765;
  unsigned int D.1766;

  if (n9 == 0) goto <D.1762>; else goto <D.1763>;
  <D.1762>:
  D.1764 = 1.0e+0 +
1.000000000000000055511151231257827021181583404541015625e-1;
  D.1765 = (long int) D.1764;
  D.1766 = (unsigned int) D.1765;
  iftmp.0 = D.1766 + 4294967295;
  goto <D.1767>;
  <D.1763>:
  iftmp.0 = (unsigned int) D.1765;
  <D.1767>:
  D.1760 = w3 >> iftmp.0;
  return D.1760;
}

note how D.1765 is used uninitialized.