[PATCH] Fix middle-end/81737

[Marek Polacek]

In my recent change I failed to check whether the type domain
of a type is non-NULL and this goof causes crashing on this
testcase.

Bootstrapped/regtested on x86_64-linux, ok for trunk?

2017-08-07  Marek Polacek  <pola...@redhat.com>

        PR middle-end/81737
        * fold-const.c (fold_indirect_ref_1): Check type_domain.

        * gcc.dg/pr81737.c: New test.

diff --git gcc/fold-const.c gcc/fold-const.c
index d563ba76766..8eaea6cce3a 100644
--- gcc/fold-const.c
+++ gcc/fold-const.c
@@ -14107,8 +14107,10 @@ fold_indirect_ref_1 (location_t loc, tree type, tree 
op0)
                   && type == TREE_TYPE (op00type))
            {
              tree type_domain = TYPE_DOMAIN (op00type);
-             tree min = TYPE_MIN_VALUE (type_domain);
-             if (min && TREE_CODE (min) == INTEGER_CST)
+             tree min;
+             if (type_domain != NULL_TREE
+                 && (min = TYPE_MIN_VALUE (type_domain))
+                 && TREE_CODE (min) == INTEGER_CST)
                {
                  offset_int off = wi::to_offset (op01);
                  offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type));
diff --git gcc/testsuite/gcc.dg/pr81737.c gcc/testsuite/gcc.dg/pr81737.c
index e69de29bb2d..493358956ef 100644
--- gcc/testsuite/gcc.dg/pr81737.c
+++ gcc/testsuite/gcc.dg/pr81737.c
@@ -0,0 +1,6 @@
+/* PR middle-end/81737 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+extern int a[];
+void fn1() { (a + 0)[1]; }

        Marek