PR rtl-optimization/51069 (verify_loop_info failed)

[Jan Hubicka]

Hi,
in this testcase peeling of loop contaiing irreducible region leads to
increasing size of the region (by removing the conditional path into it).
remove_path is not quite ready for this scenario.  Still it would be nice to
avoid us creating irreducible region in cases where they are not.

Bootstrapped/regtested x86_64-linux, OK?

int a, b, c, d, e, f, bar (void);

void
foo (int x)
{
  for (;;)
    {
      if (!x)
        {
          for (d = 6; d >= 0; d--)
            {
              while (!b)
                ;
              if (e)
                return foo (x);
              if (f)
                {
                  a = 0;
                  continue;
                }
              for (; c; c--)
                ;
            }
        }
      if (bar ())
        break;
      e = 0;
      if (x)
        for (;;)
          ;
    }
}
        PR rtl-optimization/51069
        * cfgloopmanip.c (remove_path): Removing path making irreducible
        region unconditional makes BB part of the region.

Index: cfgloopmanip.c
===================================================================
*** cfgloopmanip.c      (revision 182708)
--- cfgloopmanip.c      (working copy)
*************** remove_path (edge e)
*** 290,295 ****
--- 290,296 ----
    int i, nrem, n_bord_bbs;
    sbitmap seen;
    bool irred_invalidated = false;
+   edge_iterator ei;
  
    if (!can_remove_branch_p (e))
      return false;
*************** remove_path (edge e)
*** 329,337 ****
    /* Find "border" hexes -- i.e. those with predecessor in removed path.  */
    for (i = 0; i < nrem; i++)
      SET_BIT (seen, rem_bbs[i]->index);
    for (i = 0; i < nrem; i++)
      {
-       edge_iterator ei;
        bb = rem_bbs[i];
        FOR_EACH_EDGE (ae, ei, rem_bbs[i]->succs)
        if (ae->dest != EXIT_BLOCK_PTR && !TEST_BIT (seen, ae->dest->index))
--- 330,341 ----
    /* Find "border" hexes -- i.e. those with predecessor in removed path.  */
    for (i = 0; i < nrem; i++)
      SET_BIT (seen, rem_bbs[i]->index);
+   FOR_EACH_EDGE (ae, ei, e->src->succs)
+     if (ae != e && ae->dest != EXIT_BLOCK_PTR && !TEST_BIT (seen, 
ae->dest->index)
+       && ae->flags & EDGE_IRREDUCIBLE_LOOP)
+       irred_invalidated = true;
    for (i = 0; i < nrem; i++)
      {
        bb = rem_bbs[i];
        FOR_EACH_EDGE (ae, ei, rem_bbs[i]->succs)
        if (ae->dest != EXIT_BLOCK_PTR && !TEST_BIT (seen, ae->dest->index))