[Bug tree-optimization/23855] loop header should also be pulled out of the inner loop too

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=23855

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

           What    |Removed                     |Added
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                 CC|                            |ysrumyan at gmail dot com

--- Comment #30 from Richard Biener <rguenth at gcc dot gnu.org> ---
Well, unfortunately it doesn't fully work for

void bar(void);
void foo(int ie, int je, int ke)
{
  int i, j, k;
  for (k=0; k<ke; ++k)
    for (j=0; j<je; ++j)
      for (i=0; i<ie; ++i)
        bar();
}

it hoists the header check one level but it doesn't manage to hoist the
ie > 0 check all the way up out of the k loop.  I suppose iterating
find_loop_guard in some way would work.  I have a patch in testing.