re PR c++/77803 (Bogus implicit-fallthrough warning)

	PR c++/77803
	* gimplify.c (last_stmt_in_scope): Add check for FALLTHROUGH ().

	* g++.dg/warn/Wimplicit-fallthrough-1.C: New test.

From-SVN: r240861

gcc/ChangeLog

+2016-10-07  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/77803
+	* gimplify.c (last_stmt_in_scope): Add check for FALLTHROUGH ().
+
 2016-10-07  Richard Biener  <rguenther@suse.de>
 
 	* bitmap.h: Document constraints on bitmap modification while

gcc/gimplify.c

@@ -1687,6 +1687,8 @@ last_stmt_in_scope (gimple *stmt)
 	stmt = gimple_seq_last_stmt (gimple_try_eval (try_stmt));
 	gimple *last_eval = last_stmt_in_scope (stmt);
 	if (gimple_stmt_may_fallthru (last_eval)
+	    && (last_eval == NULL
+		|| !gimple_call_internal_p (last_eval, IFN_FALLTHROUGH))
 	    && gimple_try_kind (try_stmt) == GIMPLE_TRY_FINALLY)
 	  {
 	    stmt = gimple_seq_last_stmt (gimple_try_cleanup (try_stmt));

gcc/testsuite/ChangeLog

+2016-10-07  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/77803
+	* g++.dg/warn/Wimplicit-fallthrough-1.C: New test.
+
 2016-10-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/77664

gcc/testsuite/g++.dg/warn/Wimplicit-fallthrough-1.C

+// PR c++/77803
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wimplicit-fallthrough" }
+
+struct A {};
+int a;
+
+void
+fn1 ()
+{
+  switch (0) {
+  case 0:
+  {
+    A b;
+    [[fallthrough]];
+  }
+  default:
+    a = 0;
+  }
+}
+
+void
+fn2 ()
+{
+  switch (0) {
+  case 0:
+  {
+    A b; // { dg-warning "statement may fall through" }
+  }
+  default:
+    a = 0;
+  }
+}