2016-09-30 Fritz Reese <fritzoreese@gmail.com>

Fix ICE for maps with zero components.

	PR fortran/77764
	* gcc/fortran/interface.c (gfc_compare_union_types): Null-guard map
	components.

	PR fortran/77764
	* gcc/testsuite/gfortran.dg/dec_union_8.f90: New testcase.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@240652 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 15 insertions, 4 deletions

diff --git a/gcc/fortran/interface.c b/gcc/fortran/interface.c
index 3f6774e630b9..04ad0e295f76 100644
--- a/gcc/fortran/interface.c
+++ b/gcc/fortran/interface.c
@@ -526,6 +526,7 @@ int
 gfc_compare_union_types (gfc_symbol *un1, gfc_symbol *un2)
 {
   gfc_component *map1, *map2, *cmp1, *cmp2;
+  gfc_symbol *map1_t, *map2_t;
 
   if (un1->attr.flavor != FL_UNION || un2->attr.flavor != FL_UNION)
     return 0;
@@ -541,16 +542,26 @@ gfc_compare_union_types (gfc_symbol *un1, gfc_symbol *un2)
      we compare the maps sequentially. */
   for (;;)
   {
-    cmp1 = map1->ts.u.derived->components;
-    cmp2 = map2->ts.u.derived->components;
+    map1_t = map1->ts.u.derived;
+    map2_t = map2->ts.u.derived;
+
+    cmp1 = map1_t->components;
+    cmp2 = map2_t->components;
+
+    /* Protect against null components.  */
+    if (map1_t->attr.zero_comp != map2_t->attr.zero_comp)
+      return 0;
+
+    if (map1_t->attr.zero_comp)
+      return 1;
+
     for (;;)
     {
       /* No two fields will ever point to the same map type unless they are
          the same component, because one map field is created with its type
          declaration. Therefore don't worry about recursion here. */
       /* TODO: worry about recursion into parent types of the unions? */
-      if (compare_components (cmp1, cmp2,
-            map1->ts.u.derived, map2->ts.u.derived) == 0)
+      if (compare_components (cmp1, cmp2, map1_t, map2_t) == 0)
         return 0;
 
       cmp1 = cmp1->next;