[PATCH] Fix ubsan ICE (PR sanitizer/79897)

[Jakub Jelinek]

Hi!

Apparently fold_build_addr_expr doesn't make the argument addressable,
it is only made addressable during following gimplification and that is too
late here.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?

2017-03-06  Jakub Jelinek  <ja...@redhat.com>

        PR sanitizer/79897
        * ubsan.c (ubsan_encode_value): Call mark_addressable on the
        temporary.

--- gcc/ubsan.c.jj      2017-02-21 09:03:57.000000000 +0100
+++ gcc/ubsan.c 2017-03-06 21:37:32.013422810 +0100
@@ -145,6 +145,7 @@ ubsan_encode_value (tree t, bool in_expa
             code by making vars unnecessarily addressable.  */
          tree var = create_tmp_var (type);
          tree tem = build2 (MODIFY_EXPR, void_type_node, var, t);
+         mark_addressable (var);
          if (in_expand_p)
            {
              rtx mem
--- gcc/testsuite/c-c++-common/ubsan/pr79897.c.jj       2017-03-06 
21:48:01.007297214 +0100
+++ gcc/testsuite/c-c++-common/ubsan/pr79897.c  2017-03-06 21:42:56.505230894 
+0100
@@ -0,0 +1,15 @@
+/* PR sanitizer/79897 */
+/* { dg-do compile } */
+/* { dg-options "-fsanitize=enum -O2" } */
+
+enum E
+{
+  A = 0,
+  B = ~0U + 1LL
+} x = A;
+
+int
+main ()
+{
+  return x != A;
+}

        Jakub