re PR debug/44694 (Long var tracking compile time of GiNaC tests)

	PR debug/44694
	* dwarf2out.c (reg_loc_descriptor): For eliminated arg_pointer_rtx
	or frame_pointer_rtx use DW_OP_fbreg offset DW_OP_stack_value.

From-SVN: r161662

gcc/ChangeLog

+2010-07-01  Jakub Jelinek  <jakub@redhat.com>
+
+	PR debug/44694
+	* dwarf2out.c (reg_loc_descriptor): For eliminated arg_pointer_rtx
+	or frame_pointer_rtx use DW_OP_fbreg offset DW_OP_stack_value.
+
 2010-07-01  Richard Guenther  <rguenther@suse.de>
 
 	* emit-rtl.c (set_mem_attributes_minus_bitpos): Use unsigned

gcc/dwarf2out.c

@@ -12999,6 +12999,26 @@ reg_loc_descriptor (rtx rtl, enum var_init_status initialized)
   if (REGNO (rtl) >= FIRST_PSEUDO_REGISTER)
     return 0;
 
+  /* We only use "frame base" when we're sure we're talking about the
+     post-prologue local stack frame.  We do this by *not* running
+     register elimination until this point, and recognizing the special
+     argument pointer and soft frame pointer rtx's.
+     Use DW_OP_fbreg offset DW_OP_stack_value in this case.  */
+  if ((rtl == arg_pointer_rtx || rtl == frame_pointer_rtx)
+      && eliminate_regs (rtl, VOIDmode, NULL_RTX) != rtl)
+    {
+      dw_loc_descr_ref result = NULL;
+
+      if (dwarf_version >= 4 || !dwarf_strict)
+	{
+	  result = mem_loc_descriptor (rtl, VOIDmode, initialized);
+	  if (result)
+	    add_loc_descr (&result,
+			   new_loc_descr (DW_OP_stack_value, 0, 0));
+	}
+      return result;
+    }
+
   regs = targetm.dwarf_register_span (rtl);
 
   if (hard_regno_nregs[REGNO (rtl)][GET_MODE (rtl)] > 1 || regs)