re PR middle-end/80707 (r247844 causes error: extra outgoing edge)

gcc/
	PR middle-end/80707
	* tree-cfg.c: Remove cfg edges of unreachable case statements.

gcc/testsuite/
	PR middle-end/80707
	* g++.dg/pr80707.C: New test.

From-SVN: r247984

gcc/ChangeLog

+2017-05-12  Peter Bergner  <bergner@vnet.ibm.com>
+
+	PR middle-end/80707
+	* tree-cfg.c: Remove cfg edges of unreachable case statements.
+
 2017-05-12  Will Schmidt  <will_schmidt@vnet.ibm.com>
 
 	* config/rs6000/rs6000.c (rs6000_gimple_fold_builtin): Add handling for

gcc/testsuite/ChangeLog

+2017-05-12  Peter Bergner  <bergner@vnet.ibm.com>
+
+	PR middle-end/80707
+	* g++.dg/pr80707.C: New test.
+
 2017-05-12  Will Schmidt  <will_schmidt@vnet.ibm.com>
 
 	* gcc.target/powerpc/fold-vec-div-float.c: New.

gcc/testsuite/g++.dg/pr80707.C

+// PR middle-end/80707 ICE: extra outgoing edge causes verify_flow_info error.
+// { dg-do compile }
+// { dg-options "-O3" } */
+
+struct A {
+  int m_fn1(int &) const;
+};
+int A::m_fn1(int &p1) const {
+  int a[6];
+  int b = 0;
+  for (int i;; i++) {
+    if (a[i])
+      break;
+    b++;
+  }
+  while (b) {
+    int c;
+    switch (b) {
+    case 1:
+      c = 0;
+      break;
+    case 5:
+      c = a[0];
+    }
+    if (c)
+      p1 = 0;
+    b--;
+  }
+}

gcc/tree-cfg.c

@@ -1684,6 +1684,10 @@ group_case_labels_stmt (gswitch *stmt)
 	  || (EDGE_COUNT (base_bb->succs) == 0
 	      && gimple_seq_unreachable_p (bb_seq (base_bb))))
 	{
+	  edge e;
+	  if (base_bb != default_bb
+	      && (e = find_edge (gimple_bb (stmt), base_bb)) != NULL)
+	    remove_edge_and_dominated_blocks (e);
 	  gimple_switch_set_label (stmt, i, NULL_TREE);
 	  i++;
 	  new_size--;