re PR c/12553 ([tree-ssa] ICE in gimplify_expr with volatiles)

        PR c/12553
        * tree.c (build1) <ADDR_EXPR>: Set TREE_SIDE_EFFECTS
        appropriately.

From-SVN: r72726

gcc/testsuite/gcc.dg/volatile1.c

+/* PR c/12553: we were erroneously setting TREE_SIDE_EFFECTS on &y, which
+   confused tree-ssa.  */
+
+void f()
+{
+  int x;
+  volatile int y;
+  &x == &y;
+}