[patch] arm,rx: don't ICE on naked functions with local vars

[DJ Delorie]

This patch tests for at least one user-caused reason for this
assertion failing - requiring a local frame in a naked function.  For
this case at least, it would be better to trigger an error than to
ICE.  OK?

static int bar;
void __attribute__((naked)) function(void) {
   int foo, result;
   result = subFunction(&foo, &bar);   // ICE here
}

        * expr.c (expand_expr_addr_expr_1): Detect a user request for
        a local frame in a naked function, and produce a suitable
        error for that specific case.

Index: expr.c
===================================================================
--- expr.c      (revision 176766)
+++ expr.c      (working copy)
@@ -6943,13 +6943,22 @@ expand_expr_addr_expr_1 (tree exp, rtx t
                                modifier == EXPAND_INITIALIZER
                                ? EXPAND_INITIALIZER : EXPAND_CONST_ADDRESS);
 
          /* If the DECL isn't in memory, then the DECL wasn't properly
             marked TREE_ADDRESSABLE, which will be either a front-end
             or a tree optimizer bug.  */
-         gcc_assert (MEM_P (result));
+
+         if (TREE_ADDRESSABLE (exp)
+             && ! MEM_P (result)
+             && ! targetm.calls.allocate_stack_slots_for_args())
+           {
+             error ("local frame unavailable (naked function?)");
+             return result;
+           }
+         else
+           gcc_assert (MEM_P (result));
          result = XEXP (result, 0);
 
          /* ??? Is this needed anymore?  */
          if (DECL_P (exp) && !TREE_USED (exp) == 0)
            {
              assemble_external (exp);