2017-05-30  Jakub Jelinek  <jakub@redhat.com>

 	Backported from mainline

	2016-12-21  Jakub Jelinek  <jakub@redhat.com>

	PR c/77767

	* c-decl.c (grokdeclarator): If *expr is non-NULL, append expression

	to *expr instead of overwriting it.

	* gcc.c-torture/execute/pr77767.c: New test.

--- gcc/c/c-decl.c

+++ gcc/c/c-decl.c

@@ -5409,11 +5409,21 @@ grokdeclarator (const struct c_declarator *declarator,

   if (TREE_CODE (type) == ERROR_MARK)

     return error_mark_node;

   if (expr == NULL)

-    expr = &expr_dummy;

+    {

+      expr = &expr_dummy;

+      expr_dummy = NULL_TREE;

+    }

   if (expr_const_operands == NULL)

     expr_const_operands = &expr_const_operands_dummy;

-  *expr = declspecs->expr;

+  if (declspecs->expr)

+    {

+      if (*expr)

+	*expr = build2 (COMPOUND_EXPR, TREE_TYPE (declspecs->expr), *expr,

+			declspecs->expr);

+      else

+	*expr = declspecs->expr;

+    }

   *expr_const_operands = declspecs->expr_const_operands;

   if (decl_context == FUNCDEF)

--- /dev/null

+++ gcc/testsuite/gcc.c-torture/execute/pr77767.c

@@ -0,0 +1,16 @@

+/* PR c/77767 */

+

+void

+foo (int a, int b[a++], int c, int d[c++])

+{

+  if (a != 2 || c != 2)

+    __builtin_abort ();

+}

+

+int

+main ()

+{

+  int e[10];

+  foo (1, e, 1, e);

+  return 0;

+}