[PATCH, PR67405, committed] Avoid NULL pointer dereference

[Ilya Enkovich <enkovich.gnu@gmail.com>]

Hi,

This fixes an ICE by adding a NULL check.  Bootstrapped and regtested for x86_64-unknown-linux-gnu.  Applied to trunk.  Does this need to be ported to gcc-5-branch?

Thanks,
Ilya
--
gcc/

2015-09-01  Ilya Enkovich  <enkovich.gnu@gmail.com>

	PR target/67405
	* tree-chkp.c (chkp_find_bound_slots_1): Add NULL check.

gcc/testsuite/

2015-09-01  Ilya Enkovich  <enkovich.gnu@gmail.com>

	PR target/67405
	* g++.dg/pr67405.C: New test.


diff --git a/gcc/testsuite/g++.dg/pr67405.C b/gcc/testsuite/g++.dg/pr67405.C
new file mode 100644
index 0000000..5055921
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr67405.C
@@ -0,0 +1,11 @@
+// { dg-do compile }
+
+struct S
+{
+  S f; // { dg-error "incomplete type" }
+};
+
+void
+fn1 (S p1)
+{
+}
diff --git a/gcc/tree-chkp.c b/gcc/tree-chkp.c
index 8c1b48c..2489abb 100644
--- a/gcc/tree-chkp.c
+++ b/gcc/tree-chkp.c
@@ -1667,8 +1667,9 @@ chkp_find_bound_slots_1 (const_tree type, bitmap have_bound,
       for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
 	if (TREE_CODE (field) == FIELD_DECL)
 	  {
-	    HOST_WIDE_INT field_offs
-	      = TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field));
+	    HOST_WIDE_INT field_offs = 0;
+	    if (DECL_FIELD_BIT_OFFSET (field))
+	      field_offs += TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field));
 	    if (DECL_FIELD_OFFSET (field))
 	      field_offs += TREE_INT_CST_LOW (DECL_FIELD_OFFSET (field)) * 8;
 	    chkp_find_bound_slots_1 (TREE_TYPE (field), have_bound,