[Committed] s390 bootstrap: last_bb_active set but not used

[Andreas Krebbel]

Hi,

this fixes a bootstrap problem on s390.  s390 doesn't have "return"
nor "simple_return" expanders so the last_bb_active variable stays
unused in thread_prologue_and_epilogue_insns.

Committed to mainline as obvious.

Bye,

-Andreas-


2011-10-06  Andreas Krebbel  <andreas.kreb...@de.ibm.com>

        * function.c (thread_prologue_and_epilogue_insns): Mark
        last_bb_active as possibly unused.  It is unused for targets which
        do neither have "return" nor "simple_return" expanders.


Index: gcc/function.c
===================================================================
*** gcc/function.c.orig
--- gcc/function.c
*************** thread_prologue_and_epilogue_insns (void
*** 5453,5459 ****
  {
    bool inserted;
    basic_block last_bb;
!   bool last_bb_active;
  #ifdef HAVE_simple_return
    bool unconverted_simple_returns = false;
    basic_block simple_return_block_hot = NULL;
--- 5453,5459 ----
  {
    bool inserted;
    basic_block last_bb;
!   bool last_bb_active ATTRIBUTE_UNUSED;
  #ifdef HAVE_simple_return
    bool unconverted_simple_returns = false;
    basic_block simple_return_block_hot = NULL;