re PR target/7042 (cris-elf miscompiles line_hints in ghostscript - "return" delay slot bug)

	PR target/7042
	* reorg.c (make_return_insns) [DELAY_SLOTS_FOR_EPILOGUE]: Exit
	early if current_function_epilogue_delay_list is non-empty.
	* config/cris/cris.md ("return"): Add sanity check asserting that
	current_function_epilogue_delay_list is empty.

From-SVN: r54668

gcc/ChangeLog

+2002-06-16  Hans-Peter Nilsson  <hp@axis.com>
+
+	PR target/7042
+	* reorg.c (make_return_insns) [DELAY_SLOTS_FOR_EPILOGUE]: Exit
+	early if current_function_epilogue_delay_list is non-empty.
+	* config/cris/cris.md ("return"): Add sanity check asserting that
+	current_function_epilogue_delay_list is empty.
+
 2002-06-16  Jeff Law <law@redhat.com>
 
 	* toplev.c (rest_of_compilation): Perform a simpler, less costly

gcc/config/cris/cris.md

@@ -3394,6 +3394,11 @@
   /* Just needs to hold a 'movem [sp+],rN'.  */
   char rd[sizeof (\"movem [$sp+],$r99\")];
 
+  /* Try to avoid reorg.c surprises; avoid emitting invalid code, prefer
+     crashing.  This test would have avoided invalid code for target/7042.  */
+  if (current_function_epilogue_delay_list != NULL)
+    abort ();
+
   *rd = 0;
 
   /* Start from the last call-saved register.  We know that we have a

gcc/reorg.c

@@ -3485,6 +3485,17 @@ make_return_insns (first)
   rtx real_return_label = end_of_function_label;
   int slots, i;
 
+#ifdef DELAY_SLOTS_FOR_EPILOGUE
+  /* If a previous pass filled delay slots in the epilogue, things get a
+     bit more complicated, as those filler insns would generally (without
+     data flow analysis) have to be executed after any existing branch
+     delay slot filler insns.  It is also unknown whether such a
+     transformation would actually be profitable.  Note that the existing
+     code only cares for branches with (some) filled delay slots.  */
+  if (current_function_epilogue_delay_list != NULL)
+    return;
+#endif
+
   /* See if there is a RETURN insn in the function other than the one we
      made for END_OF_FUNCTION_LABEL.  If so, set up anything we can't change
      into a RETURN to jump to it.  */