re PR middle-end/71249 (-Wswitch-unreachable false positive for a compound…

re PR middle-end/71249 (-Wswitch-unreachable false positive for a compound statement containing a used label)

	PR c/71249
	* gimplify.c (gimplify_switch_expr): Look into the innermost lexical
	scope.

	* c-c++-common/Wswitch-unreachable-2.c: New test.

From-SVN: r236649

gcc/ChangeLog

+2016-05-24  Marek Polacek  <polacek@redhat.com>
+
+	PR c/71249
+	* gimplify.c (gimplify_switch_expr): Look into the innermost lexical
+	scope.
+
 2016-05-24  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/71257

gcc/gimplify.c

@@ -1605,8 +1605,9 @@ gimplify_switch_expr (tree *expr_p, gimple_seq *pre_p)
 	  && switch_body_seq != NULL)
 	{
 	  gimple_seq seq = switch_body_seq;
-	  if (gimple_code (switch_body_seq) == GIMPLE_BIND)
-	    seq = gimple_bind_body (as_a <gbind *> (switch_body_seq));
+	  /* Look into the innermost lexical scope.  */
+	  while (gimple_code (seq) == GIMPLE_BIND)
+	    seq = gimple_bind_body (as_a <gbind *> (seq));
 	  gimple *stmt = gimple_seq_first_stmt (seq);
 	  enum gimple_code code = gimple_code (stmt);
 	  if (code != GIMPLE_LABEL && code != GIMPLE_TRY)

gcc/testsuite/ChangeLog

+2016-05-24  Marek Polacek  <polacek@redhat.com>
+
+	PR c/71249
+	* c-c++-common/Wswitch-unreachable-2.c: New test.
+
 2016-05-24  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/71257

gcc/testsuite/c-c++-common/Wswitch-unreachable-2.c

+/* PR c/71249 */
+/* { dg-do compile } */
+
+int
+f (int i)
+{
+  switch (i)
+    {
+      {
+	int j;
+      foo:
+	return i; /* { dg-bogus "statement will never be executed" } */
+      };
+    case 3:
+      goto foo;
+    }
+  return i;
+}