re PR sanitizer/81212 (-Wreturn-type is disabled when used together with -fsanitize=return)

	PR c++/81212
	* tree-cfg.c (pass_warn_function_return::execute): Handle
	__builtin_ubsan_handle_missing_return like __builtin_unreachable
	with BUILTINS_LOCATION.

	* g++.dg/ubsan/pr81212.C: New test.
	* g++.dg/ubsan/return-1.C: Add -Wno-return-type to dg-options.
	* g++.dg/ubsan/return-2.C: Likewise.
	* g++.dg/ubsan/return-7.C: Likewise.

From-SVN: r255354

gcc/ChangeLog

 2017-12-02  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/81212
+	* tree-cfg.c (pass_warn_function_return::execute): Handle
+	__builtin_ubsan_handle_missing_return like __builtin_unreachable
+	with BUILTINS_LOCATION.
+
 	PR target/78643
 	PR target/80583
 	* expr.c (get_inner_reference): If DECL_MODE of a non-bitfield

gcc/testsuite/ChangeLog

 2017-12-02  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/81212
+	* g++.dg/ubsan/pr81212.C: New test.
+	* g++.dg/ubsan/return-1.C: Add -Wno-return-type to dg-options.
+	* g++.dg/ubsan/return-2.C: Likewise.
+	* g++.dg/ubsan/return-7.C: Likewise.
+
 	PR target/78643
 	PR target/80583
 	* gcc.target/i386/pr80583.c: New test.

gcc/testsuite/g++.dg/ubsan/pr81212.C

+// PR c++/81212
+// { dg-do compile }
+// { dg-options "-Wreturn-type -fsanitize=return" }
+
+struct S
+{
+  S (void *);
+  void *s;
+};
+
+S
+foo (bool x, void *y)
+{
+  if (x)
+    return S (y);
+}	// { dg-warning "control reaches end of non-void function" }

gcc/testsuite/g++.dg/ubsan/return-1.C

 // { dg-do run }
-// { dg-options "-fsanitize=return" }
+// { dg-options "-fsanitize=return -Wno-return-type" }
 // { dg-shouldfail "ubsan" }
 
 struct S { S (); ~S (); };

gcc/testsuite/g++.dg/ubsan/return-2.C

 // { dg-do run }
-// { dg-options "-fsanitize=return -fno-sanitize-recover=return" }
+// { dg-options "-fsanitize=return -fno-sanitize-recover=return -Wno-return-type" }
 
 struct S { S (); ~S (); };
 

gcc/testsuite/g++.dg/ubsan/return-7.C

 // { dg-do run }
-// { dg-options "-fsanitize=undefined" }
+// { dg-options "-fsanitize=undefined -Wno-return-type" }
 // { dg-shouldfail "ubsan" }
 
 struct S { S (); ~S (); };

gcc/tree-cfg.c

@@ -9151,10 +9151,13 @@ pass_warn_function_return::execute (function *fun)
 	  if (EDGE_COUNT (bb->succs) == 0)
 	    {
 	      gimple *last = last_stmt (bb);
+	      const enum built_in_function ubsan_missing_ret
+		= BUILT_IN_UBSAN_HANDLE_MISSING_RETURN;
 	      if (last
-		  && (LOCATION_LOCUS (gimple_location (last))
-		      == BUILTINS_LOCATION)
-		  && gimple_call_builtin_p (last, BUILT_IN_UNREACHABLE))
+		  && ((LOCATION_LOCUS (gimple_location (last))
+		       == BUILTINS_LOCATION
+		       && gimple_call_builtin_p (last, BUILT_IN_UNREACHABLE))
+		      || gimple_call_builtin_p (last, ubsan_missing_ret)))
 		{
 		  gimple_stmt_iterator gsi = gsi_for_stmt (last);
 		  gsi_prev_nondebug (&gsi);