Index: gcc/cp/typeck.c
===================================================================
--- gcc/cp/typeck.c	(revision 194568)
+++ gcc/cp/typeck.c	(working copy)
@@ -8600,6 +8600,7 @@
 cp_apply_type_quals_to_decl (int type_quals, tree decl)
 {
   tree type = TREE_TYPE (decl);
+  int was_const;
 
   if (type == error_mark_node)
     return;
@@ -8610,6 +8611,9 @@
   gcc_assert (!(TREE_CODE (type) == FUNCTION_TYPE
 		&& type_quals != TYPE_UNQUALIFIED));
 
+  /* Remember const qualifer even if we don't set TREE_READONLY */
+  was_const = type_quals & TYPE_QUAL_CONST;
+
   /* Avoid setting TREE_READONLY incorrectly.  */
   /* We used to check TYPE_NEEDS_CONSTRUCTING here, but now a constexpr
      constructor can produce constant init, so rely on cp_finish_decl to
@@ -8621,6 +8625,9 @@
     type_quals &= ~TYPE_QUAL_CONST;
 
   c_apply_type_quals_to_decl (type_quals, decl);
+
+  if (was_const)
+    TREE_WASREADONLY(decl) = 1;
 }
 
 /* Subroutine of casts_away_constness.  Make T1 and T2 point at
Index: gcc/cp/typeck2.c
===================================================================
--- gcc/cp/typeck2.c	(revision 194568)
+++ gcc/cp/typeck2.c	(working copy)
@@ -633,6 +633,7 @@
 	init = NULL_TREE;
       code = pop_stmt_list (code);
       DECL_INITIAL (dest) = init;
+      TREE_WASREADONLY (dest) = TREE_READONLY (dest);
       TREE_READONLY (dest) = 0;
     }
   else
Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c	(revision 194568)
+++ gcc/dwarf2out.c	(working copy)
@@ -18370,7 +18370,9 @@
       if (decl_by_reference_p (decl_or_origin))
 	add_type_attribute (var_die, TREE_TYPE (type), 0, 0, context_die);
       else
-	add_type_attribute (var_die, type, TREE_READONLY (decl_or_origin),
+	add_type_attribute (var_die, type,
+                TREE_READONLY (decl_or_origin) ||
+                  TREE_WASREADONLY (decl_or_origin),
 			    TREE_THIS_VOLATILE (decl_or_origin), context_die);
     }
 
Index: gcc/tree.h
===================================================================
--- gcc/tree.h	(revision 194568)
+++ gcc/tree.h	(working copy)
@@ -438,6 +438,9 @@
   unsigned deprecated_flag : 1;
   unsigned default_def_flag : 1;
 
+  unsigned wasreadonly_flag : 1;
+  unsigned spare : 7;
+
   union {
     /* The bits in the following structure should only be used with
        accessor macros that constrain inputs with tree checking.  */
@@ -1246,6 +1249,11 @@
    as "const" function (can only read its arguments).  */
 #define TREE_READONLY(NODE) (NON_TYPE_CHECK (NODE)->base.readonly_flag)
 
+/* Keep track of variables that were declared const, even if they might
+   not be placed in read-only memory.  This allows generation of more
+   accurate debug info. */
+#define TREE_WASREADONLY(NODE) (NON_TYPE_CHECK (NODE)->base.wasreadonly_flag)
+
 /* Value of expression is constant.  Always on in all ..._CST nodes.  May
    also appear in an expression or decl where the value is constant.  */
 #define TREE_CONSTANT(NODE) (NON_TYPE_CHECK (NODE)->base.constant_flag)