[PATCH] Add checking that during RTL bbs don't mix EH and non-complex predecessor edges

[Jakub Jelinek]

On Fri, Jun 15, 2018 at 09:06:16PM +0200, Jakub Jelinek wrote:
> The following patch fixes it by making sure we don't have EH landing pads
> that are reachable also by the crossing edges by splitting the EH landing
> pad bb we want to jump into and jumping (EDGE_CROSSING) only to the second
> half, leaving the first part with no actual instructions to be the EH
> landing pad.

The following patch adds verification that we don't have such basic blocks
during RTL optimizations.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

Eric, I wonder if sjlj doesn't need a similar fix to the PR86108 patch.
If it does, I think with the following patch it would trigger a checking
failure.  Not familiar with sjlj EH enough to try it myself.

2018-06-15  Jakub Jelinek  <ja...@redhat.com>

        * cfgrtl.c (rtl_verify_edges): Formatting fix.  If bb_has_eh_pred,
        verify all incoming edges are complex.

--- gcc/cfgrtl.c.jj     2018-04-09 20:15:51.237631514 +0200
+++ gcc/cfgrtl.c        2018-06-15 18:15:37.479333131 +0200
@@ -2540,15 +2540,15 @@ rtl_verify_edges (void)
            n_abnormal++;
        }
 
-        if (!has_crossing_edge
-           && JUMP_P (BB_END (bb))
-           && CROSSING_JUMP_P (BB_END (bb)))
-          {
-           print_rtl_with_bb (stderr, get_insns (), TDF_BLOCKS | TDF_DETAILS);
-            error ("Region crossing jump across same section in bb %i",
-                   bb->index);
-            err = 1;
-          }
+      if (!has_crossing_edge
+         && JUMP_P (BB_END (bb))
+         && CROSSING_JUMP_P (BB_END (bb)))
+       {
+         print_rtl_with_bb (stderr, get_insns (), TDF_BLOCKS | TDF_DETAILS);
+         error ("Region crossing jump across same section in bb %i",
+                bb->index);
+         err = 1;
+       }
 
       if (n_eh && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
        {
@@ -2606,6 +2606,18 @@ rtl_verify_edges (void)
          error ("abnormal edges for no purpose in bb %i", bb->index);
          err = 1;
        }
+      if (bb_has_eh_pred (bb))
+       {
+         FOR_EACH_EDGE (e, ei, bb->preds)
+           {
+             if (e->flags & EDGE_COMPLEX)
+               continue;
+             error ("EH incoming edge mixed with non-complex incoming edges "
+                    "in bb %i", bb->index);
+             err = 1;
+             break;
+           }
+       }
     }
 
   /* If there are partitions, do a sanity check on them: A basic block in


        Jakub