re PR tree-optimization/87280 (ICE in set_ssa_val_to, at tree-ssa-sccvn.c:3647)

2018-09-12  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/87280
	* tree-ssa-sccvn.c (process_bb): Handle the case of executable
	edge but unreachable target.
	(do_rpo_vn): For conservatively handling a PHI only mark
	the backedge executable but not the block reachable.

	* gcc.dg/torture/pr87280.c: New testcase.

From-SVN: r264241

gcc/ChangeLog

 2018-09-12  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/87280
+	* tree-ssa-sccvn.c (process_bb): Handle the case of executable
+	edge but unreachable target.
+	(do_rpo_vn): For conservatively handling a PHI only mark
+	the backedge executable but not the block reachable.
+
+2018-09-12  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/87266
 	* tree-ssa-sccvn.c (do_rpo_vn): Always iterate to not yet
 	visited blocks.

gcc/testsuite/ChangeLog

 2018-09-12  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/87280
+	* gcc.dg/torture/pr87280.c: New testcase.
+
+2018-09-12  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/87266
 	* gcc.dg/torture/pr87266-1.c: New testcase.
 	* gcc.dg/torture/pr87266-2.c: Likewise.

gcc/testsuite/gcc.dg/torture/pr87280.c

+/* { dg-do compile } */
+/* { dg-additional-options "--param rpo-vn-max-loop-depth=5" } */
+
+int uc;
+
+void
+j8 (int *xv, int f3)
+{
+  uc = 0;
+  while (uc < 1)
+    {
+    }
+
+  if (*xv == 0)
+    {
+      int *o8 = xv;
+
+      if (0)
+	{
+n3:
+	  *o8 = 0;
+	  while (*o8 < 1)
+	    {
+h5:
+	      *o8 = 0;
+	    }
+	}
+
+      while (*xv < 1)
+	if (*xv == 0)
+	  goto h5;
+
+g5:
+      ;
+    }
+
+  *xv = 0;
+  for (;;)
+    {
+      while (uc < 1)
+	{
+	}
+
+      while (f3 < 1)
+	{
+	  if (*xv == 0)
+	    goto n3;
+
+	  while (f3 < 1)
+	    while (*xv < 1)
+	      while (*xv < 1)
+		while (*xv < 1)
+		  while (*xv < 1)
+		    {
+		    }
+	}
+
+      if (*xv == 0)
+	goto g5;
+    }
+}

gcc/tree-ssa-sccvn.c

@@ -5976,15 +5976,24 @@ process_bb (rpo_elim &avail, basic_block bb,
     {
       FOR_EACH_EDGE (e, ei, bb->succs)
 	{
-	  if (e->flags & EDGE_EXECUTABLE)
-	    continue;
-	  if (dump_file && (dump_flags & TDF_DETAILS))
-	    fprintf (dump_file,
-		     "marking outgoing edge %d -> %d executable\n",
-		     e->src->index, e->dest->index);
-	  gcc_checking_assert (iterate || !(e->flags & EDGE_DFS_BACK));
-	  e->flags |= EDGE_EXECUTABLE;
-	  e->dest->flags |= BB_EXECUTABLE;
+	  if (!(e->flags & EDGE_EXECUTABLE))
+	    {
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		fprintf (dump_file,
+			 "marking outgoing edge %d -> %d executable\n",
+			 e->src->index, e->dest->index);
+	      gcc_checking_assert (iterate || !(e->flags & EDGE_DFS_BACK));
+	      e->flags |= EDGE_EXECUTABLE;
+	      e->dest->flags |= BB_EXECUTABLE;
+	    }
+	  else if (!(e->dest->flags & BB_EXECUTABLE))
+	    {
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		fprintf (dump_file,
+			 "marking destination block %d reachable\n",
+			 e->dest->index);
+	      e->dest->flags |= BB_EXECUTABLE;
+	    }
 	}
     }
   for (gimple_stmt_iterator gsi = gsi_start_bb (bb);
@@ -6124,20 +6133,37 @@ process_bb (rpo_elim &avail, basic_block bb,
 	      e->flags |= EDGE_EXECUTABLE;
 	      e->dest->flags |= BB_EXECUTABLE;
 	    }
+	  else if (!(e->dest->flags & BB_EXECUTABLE))
+	    {
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		fprintf (dump_file,
+			 "marking destination block %d reachable\n",
+			 e->dest->index);
+	      e->dest->flags |= BB_EXECUTABLE;
+	    }
 	}
       else if (gsi_one_before_end_p (gsi))
 	{
 	  FOR_EACH_EDGE (e, ei, bb->succs)
 	    {
-	      if (e->flags & EDGE_EXECUTABLE)
-		continue;
-	      if (dump_file && (dump_flags & TDF_DETAILS))
-		fprintf (dump_file,
-			 "marking outgoing edge %d -> %d executable\n",
-			 e->src->index, e->dest->index);
-	      gcc_checking_assert (iterate || !(e->flags & EDGE_DFS_BACK));
-	      e->flags |= EDGE_EXECUTABLE;
-	      e->dest->flags |= BB_EXECUTABLE;
+	      if (!(e->flags & EDGE_EXECUTABLE))
+		{
+		  if (dump_file && (dump_flags & TDF_DETAILS))
+		    fprintf (dump_file,
+			     "marking outgoing edge %d -> %d executable\n",
+			     e->src->index, e->dest->index);
+		  gcc_checking_assert (iterate || !(e->flags & EDGE_DFS_BACK));
+		  e->flags |= EDGE_EXECUTABLE;
+		  e->dest->flags |= BB_EXECUTABLE;
+		}
+	      else if (!(e->dest->flags & BB_EXECUTABLE))
+		{
+		  if (dump_file && (dump_flags & TDF_DETAILS))
+		    fprintf (dump_file,
+			     "marking destination block %d reachable\n",
+			     e->dest->index);
+		  e->dest->flags |= BB_EXECUTABLE;
+		}
 	    }
 	}
 
@@ -6399,7 +6425,6 @@ do_rpo_vn (function *fn, edge entry, bitmap exit_bbs,
 		if (e->flags & EDGE_DFS_BACK)
 		  {
 		    e->flags |= EDGE_EXECUTABLE;
-		    e->dest->flags |= BB_EXECUTABLE;
 		    /* There can be a non-latch backedge into the header
 		       which is part of an outer irreducible region.  We
 		       cannot avoid iterating this block then.  */