hw-doloop.c: New file.

	* hw-doloop.c: New file.
	* hw-doloop.h: New file.
	* Makefile.in (OBJS): Add hw-doloop.o.
	(hw-doloop.o): New rule.
	($(obj_out_file)): Add hw-doloop.h dependency.
	* config/bfin/bfin.c: Include "hw-doloop.h".
	(loop_info, DEF_VEC_P for loop_info, loop_info_d): Remove.
	(bfin_dump_loops, bfin_bb_in_loop, bfin_scan_loop): Remove.
	(hwloop_optimize): Renamed from bfin_optimize_loop.  Argument
	type changed to hwloop_info.  Return bool, true if the loop was
	successfully optimized.  Remove code that was moved to
	hw-doloop.c, and adjust other parts.
	(hwloop_fail): New static function, containing parts that used
	to be in bfin_optimize_loop.
	(bfin_discover_loop, bfin_discover_loops, free_loops,
	bfin_reorder_loops): Remove.
	(hwloop_pattern_reg): New static function.
	(bfin_doloop_hooks): New variable.
	(bfin_reorg_loops): Remove most code, call reorg_loops.
	* config/bfin/bfin.md (doloop_end splitter): Also enable if
	loop counter is a memory_operand.

From-SVN: r175985

6 files changed, 928 insertions, 668 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 35d8859..f840e57 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,27 @@
+2011-07-07  Bernd Schmidt  <bernds@codesourcery.com>
+
+	* hw-doloop.c: New file.
+	* hw-doloop.h: New file.
+	* Makefile.in (OBJS): Add hw-doloop.o.
+	(hw-doloop.o): New rule.
+	($(obj_out_file)): Add hw-doloop.h dependency.
+	* config/bfin/bfin.c: Include "hw-doloop.h".
+	(loop_info, DEF_VEC_P for loop_info, loop_info_d): Remove.
+	(bfin_dump_loops, bfin_bb_in_loop, bfin_scan_loop): Remove.
+	(hwloop_optimize): Renamed from bfin_optimize_loop.  Argument
+	type changed to hwloop_info.  Return bool, true if the loop was
+	successfully optimized.  Remove code that was moved to
+	hw-doloop.c, and adjust other parts.
+	(hwloop_fail): New static function, containing parts that used
+	to be in bfin_optimize_loop.
+	(bfin_discover_loop, bfin_discover_loops, free_loops,
+	bfin_reorder_loops): Remove.
+	(hwloop_pattern_reg): New static function.
+	(bfin_doloop_hooks): New variable.
+	(bfin_reorg_loops): Remove most code, call reorg_loops.
+	* config/bfin/bfin.md (doloop_end splitter): Also enable if
+	loop counter is a memory_operand.
+
 2011-07-07  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* config.gcc: Support --with-multilib-list for x86 Linux
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 8211911..d09423d 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1300,6 +1300,7 @@ OBJS = \
 	graphite-sese-to-poly.o \
 	gtype-desc.o \
 	haifa-sched.o \
+	hw-doloop.o \
 	hwint.o \
 	ifcvt.o \
 	implicit-zee.o \
@@ -3552,13 +3553,16 @@ target-globals.o : target-globals.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
    $(TM_H) insn-config.h $(MACHMODE_H) $(GGC_H) toplev.h target-globals.h \
    $(FLAGS_H) $(REGS_H) $(RTL_H) reload.h expmed.h $(EXPR_H) $(OPTABS_H) \
    $(LIBFUNCS_H) $(CFGLOOP_H) $(IRA_INT_H) builtins.h gcse.h bb-reorder.h
-
+hw-doloop.o : hw-doloop.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
+   $(RTL_H) $(FLAGS_H) $(EXPR_H) hard-reg-set.h $(BASIC_BLOCK_H) $(TM_P_H) \
+   $(DF_H) $(CFGLAYOUT_H) $(CFGLOOP_H) output.h $(RECOG_H) $(TARGET_H) \
+   $(REGS_H) hw-doloop.h
 $(out_object_file): $(out_file) $(CONFIG_H) coretypes.h $(TM_H) $(TREE_H) \
    $(RTL_H) $(REGS_H) hard-reg-set.h insn-config.h conditions.h \
    output.h $(INSN_ATTR_H) $(SYSTEM_H) toplev.h $(DIAGNOSTIC_CORE_H) \
    $(TARGET_H) $(LIBFUNCS_H) $(TARGET_DEF_H) $(FUNCTION_H) $(SCHED_INT_H) \
    $(TM_P_H) $(EXPR_H) langhooks.h $(GGC_H) $(OPTABS_H) $(REAL_H) \
-   tm-constrs.h $(GIMPLE_H) $(DF_H) cselib.h $(COMMON_TARGET_H)
+   tm-constrs.h $(GIMPLE_H) $(DF_H) cselib.h $(COMMON_TARGET_H) hw-doloop.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) \
 		$(out_file) $(OUTPUT_OPTION)
 
diff --git a/gcc/config/bfin/bfin.c b/gcc/config/bfin/bfin.c
index 22fdfb7..f5b45dc 100644
--- a/gcc/config/bfin/bfin.c
+++ b/gcc/config/bfin/bfin.c
@@ -56,6 +56,7 @@
 #include "timevar.h"
 #include "df.h"
 #include "sel-sched.h"
+#include "hw-doloop.h"
 #include "opts.h"
 
 /* A C structure for machine-specific, per-function data.
@@ -3381,157 +3382,6 @@ bfin_hardware_loop (void)
 /* Maximum distance of the LSETUP instruction from the loop start.  */
 #define MAX_LSETUP_DISTANCE 30
 
-/* We need to keep a vector of loops */
-typedef struct loop_info_d *loop_info;
-DEF_VEC_P (loop_info);
-DEF_VEC_ALLOC_P (loop_info,heap);
-
-/* Information about a loop we have found (or are in the process of
-   finding).  */
-struct GTY (()) loop_info_d
-{
-  /* loop number, for dumps */
-  int loop_no;
-
-  /* All edges that jump into and out of the loop.  */
-  VEC(edge,gc) *incoming;
-
-  /* We can handle two cases: all incoming edges have the same destination
-     block, or all incoming edges have the same source block.  These two
-     members are set to the common source or destination we found, or NULL
-     if different blocks were found.  If both are NULL the loop can't be
-     optimized.  */
-  basic_block incoming_src;
-  basic_block incoming_dest;
-
-  /* First block in the loop.  This is the one branched to by the loop_end
-     insn.  */
-  basic_block head;
-
-  /* Last block in the loop (the one with the loop_end insn).  */
-  basic_block tail;
-
-  /* The successor block of the loop.  This is the one the loop_end insn
-     falls into.  */
-  basic_block successor;
-
-  /* The last instruction in the tail.  */
-  rtx last_insn;
-
-  /* The loop_end insn.  */
-  rtx loop_end;
-
-  /* The iteration register.  */
-  rtx iter_reg;
-
-  /* The new label placed at the beginning of the loop. */
-  rtx start_label;
-
-  /* The new label placed at the end of the loop. */
-  rtx end_label;
-
-  /* The length of the loop.  */
-  int length;
-
-  /* The nesting depth of the loop.  */
-  int depth;
-
-  /* Nonzero if we can't optimize this loop.  */
-  int bad;
-
-  /* True if we have visited this loop.  */
-  int visited;
-
-  /* True if this loop body clobbers any of LC0, LT0, or LB0.  */
-  int clobber_loop0;
-
-  /* True if this loop body clobbers any of LC1, LT1, or LB1.  */
-  int clobber_loop1;
-
-  /* Next loop in the graph. */
-  struct loop_info_d *next;
-
-  /* Immediate outer loop of this loop.  */
-  struct loop_info_d *outer;
-
-  /* Vector of blocks only within the loop, including those within
-     inner loops.  */
-  VEC (basic_block,heap) *blocks;
-
-  /* Same information in a bitmap.  */
-  bitmap block_bitmap;
-
-  /* Vector of inner loops within this loop  */
-  VEC (loop_info,heap) *loops;
-};
-
-static void
-bfin_dump_loops (loop_info loops)
-{
-  loop_info loop;
-
-  for (loop = loops; loop; loop = loop->next)
-    {
-      loop_info i;
-      basic_block b;
-      unsigned ix;
-
-      fprintf (dump_file, ";; loop %d: ", loop->loop_no);
-      if (loop->bad)
-	fprintf (dump_file, "(bad) ");
-      fprintf (dump_file, "{head:%d, depth:%d}", loop->head->index, loop->depth);
-
-      fprintf (dump_file, " blocks: [ ");
-      FOR_EACH_VEC_ELT (basic_block, loop->blocks, ix, b)
-	fprintf (dump_file, "%d ", b->index);
-      fprintf (dump_file, "] ");
-
-      fprintf (dump_file, " inner loops: [ ");
-      FOR_EACH_VEC_ELT (loop_info, loop->loops, ix, i)
-	fprintf (dump_file, "%d ", i->loop_no);
-      fprintf (dump_file, "]\n");
-    }
-  fprintf (dump_file, "\n");
-}
-
-/* Scan the blocks of LOOP (and its inferiors) looking for basic block
-   BB. Return true, if we find it.  */
-
-static bool
-bfin_bb_in_loop (loop_info loop, basic_block bb)
-{
-  return bitmap_bit_p (loop->block_bitmap, bb->index);
-}
-
-/* Scan the blocks of LOOP (and its inferiors) looking for uses of
-   REG.  Return true, if we find any.  Don't count the loop's loop_end
-   insn if it matches LOOP_END.  */
-
-static bool
-bfin_scan_loop (loop_info loop, rtx reg, rtx loop_end)
-{
-  unsigned ix;
-  basic_block bb;
-
-  FOR_EACH_VEC_ELT (basic_block, loop->blocks, ix, bb)
-    {
-      rtx insn;
-
-      for (insn = BB_HEAD (bb);
-	   insn != NEXT_INSN (BB_END (bb));
-	   insn = NEXT_INSN (insn))
-	{
-	  if (!INSN_P (insn))
-	    continue;
-	  if (insn == loop_end)
-	    continue;
-	  if (reg_mentioned_p (reg, PATTERN (insn)))
-	    return true;
-	}
-    }
-  return false;
-}
-
 /* Estimate the length of INSN conservatively.  */
 
 static int
@@ -3559,67 +3409,32 @@ length_for_loop (rtx insn)
 
 /* Optimize LOOP.  */
 
-static void
-bfin_optimize_loop (loop_info loop)
+static bool
+hwloop_optimize (hwloop_info loop)
 {
   basic_block bb;
-  loop_info inner;
+  hwloop_info inner;
   rtx insn, last_insn;
   rtx loop_init, start_label, end_label;
-  rtx reg_lc0, reg_lc1, reg_lt0, reg_lt1, reg_lb0, reg_lb1;
   rtx iter_reg, scratchreg, scratch_init, scratch_init_insn;
   rtx lc_reg, lt_reg, lb_reg;
   rtx seq, seq_end;
   int length;
   unsigned ix;
-  int inner_depth = 0;
-
-  if (loop->visited)
-    return;
-
-  loop->visited = 1;
-
-  if (loop->bad)
-    {
-      if (dump_file)
-	fprintf (dump_file, ";; loop %d bad when found\n", loop->loop_no);
-      goto bad_loop;
-    }
-
-  /* Every loop contains in its list of inner loops every loop nested inside
-     it, even if there are intermediate loops.  This works because we're doing
-     a depth-first search here and never visit a loop more than once.  */
-  FOR_EACH_VEC_ELT (loop_info, loop->loops, ix, inner)
-    {
-      bfin_optimize_loop (inner);
-
-      if (!inner->bad && inner_depth < inner->depth)
-	{
-	  inner_depth = inner->depth;
+  bool clobber0, clobber1;
 
-	  loop->clobber_loop0 |= inner->clobber_loop0;
-	  loop->clobber_loop1 |= inner->clobber_loop1;
-	}
-    }
-
-  loop->depth = inner_depth + 1;
   if (loop->depth > MAX_LOOP_DEPTH)
     {
       if (dump_file)
 	fprintf (dump_file, ";; loop %d too deep\n", loop->loop_no);
-      goto bad_loop;
+      return false;
     }
 
   /* Get the loop iteration register.  */
   iter_reg = loop->iter_reg;
 
-  if (!REG_P (iter_reg))
-    {
-      if (dump_file)
-	fprintf (dump_file, ";; loop %d iteration count not in a register\n",
-		 loop->loop_no);
-      goto bad_loop;
-    }
+  gcc_assert (REG_P (iter_reg));
+
   scratchreg = NULL_RTX;
   scratch_init = iter_reg;
   scratch_init_insn = NULL_RTX;
@@ -3680,7 +3495,7 @@ bfin_optimize_loop (loop_info loop)
 	  if (dump_file)
 	    fprintf (dump_file, ";; loop %d lsetup not before loop_start\n",
 		     loop->loop_no);
-	  goto bad_loop;
+	  return false;
 	}
 
       /* Account for the pop of a scratch register where necessary.  */
@@ -3692,7 +3507,7 @@ bfin_optimize_loop (loop_info loop)
 	{
 	  if (dump_file)
 	    fprintf (dump_file, ";; loop %d lsetup too far away\n", loop->loop_no);
-	  goto bad_loop;
+	  return false;
 	}
     }
 
@@ -3710,7 +3525,7 @@ bfin_optimize_loop (loop_info loop)
       if (dump_file)
 	fprintf (dump_file, ";; loop %d start_label not before loop_end\n",
 		 loop->loop_no);
-      goto bad_loop;
+      return false;
     }
 
   loop->length = length;
@@ -3718,58 +3533,29 @@ bfin_optimize_loop (loop_info loop)
     {
       if (dump_file)
 	fprintf (dump_file, ";; loop %d too long\n", loop->loop_no);
-      goto bad_loop;
+      return false;
     }
 
   /* Scan all the blocks to make sure they don't use iter_reg.  */
-  if (bfin_scan_loop (loop, iter_reg, loop->loop_end))
+  if (loop->iter_reg_used || loop->iter_reg_used_outside)
     {
       if (dump_file)
 	fprintf (dump_file, ";; loop %d uses iterator\n", loop->loop_no);
-      goto bad_loop;
-    }
-
-  /* Scan all the insns to see if the loop body clobber
-     any hardware loop registers. */
-
-  reg_lc0 = gen_rtx_REG (SImode, REG_LC0);
-  reg_lc1 = gen_rtx_REG (SImode, REG_LC1);
-  reg_lt0 = gen_rtx_REG (SImode, REG_LT0);
-  reg_lt1 = gen_rtx_REG (SImode, REG_LT1);
-  reg_lb0 = gen_rtx_REG (SImode, REG_LB0);
-  reg_lb1 = gen_rtx_REG (SImode, REG_LB1);
-
-  FOR_EACH_VEC_ELT (basic_block, loop->blocks, ix, bb)
-    {
-      rtx insn;
-
-      for (insn = BB_HEAD (bb);
-	   insn != NEXT_INSN (BB_END (bb));
-	   insn = NEXT_INSN (insn))
-	{
-	  if (!INSN_P (insn))
-	    continue;
-
-	  if (reg_set_p (reg_lc0, insn)
-	      || reg_set_p (reg_lt0, insn)
-	      || reg_set_p (reg_lb0, insn))
-	    loop->clobber_loop0 = 1;
-	  
-	  if (reg_set_p (reg_lc1, insn)
-	      || reg_set_p (reg_lt1, insn)
-	      || reg_set_p (reg_lb1, insn))
-	    loop->clobber_loop1 |= 1;
-	}
+      return false;
     }
 
-  if ((loop->clobber_loop0 && loop->clobber_loop1)
-      || (loop->depth == MAX_LOOP_DEPTH && loop->clobber_loop0))
+  clobber0 = (TEST_HARD_REG_BIT (loop->regs_set_in_loop, REG_LC0)
+	      || TEST_HARD_REG_BIT (loop->regs_set_in_loop, REG_LB0)
+	      || TEST_HARD_REG_BIT (loop->regs_set_in_loop, REG_LT0));
+  clobber1 = (TEST_HARD_REG_BIT (loop->regs_set_in_loop, REG_LC1)
+	      || TEST_HARD_REG_BIT (loop->regs_set_in_loop, REG_LB1)
+	      || TEST_HARD_REG_BIT (loop->regs_set_in_loop, REG_LT1));
+  if (clobber0 && clobber1)
     {
-      loop->depth = MAX_LOOP_DEPTH + 1;
       if (dump_file)
 	fprintf (dump_file, ";; loop %d no loop reg available\n",
 		 loop->loop_no);
-      goto bad_loop;
+      return false;
     }
 
   /* There should be an instruction before the loop_end instruction
@@ -3814,7 +3600,7 @@ bfin_optimize_loop (loop_info loop)
       if (dump_file)
 	fprintf (dump_file, ";; loop %d has no last instruction\n",
 		 loop->loop_no);
-      goto bad_loop;
+      return false;
     }
 
   if (JUMP_P (last_insn) && !any_condjump_p (last_insn))
@@ -3822,7 +3608,7 @@ bfin_optimize_loop (loop_info loop)
       if (dump_file)
 	fprintf (dump_file, ";; loop %d has bad last instruction\n",
 		 loop->loop_no);
-      goto bad_loop;
+      return false;
     }
   /* In all other cases, try to replace a bad last insn with a nop.  */
   else if (JUMP_P (last_insn)
@@ -3838,7 +3624,7 @@ bfin_optimize_loop (loop_info loop)
 	{
 	  if (dump_file)
 	    fprintf (dump_file, ";; loop %d too long\n", loop->loop_no);
-	  goto bad_loop;
+	  return false;
 	}
       if (dump_file)
 	fprintf (dump_file, ";; loop %d has bad last insn; replace with nop\n",
@@ -3854,19 +3640,19 @@ bfin_optimize_loop (loop_info loop)
   end_label = gen_label_rtx ();
   iter_reg = loop->iter_reg;
 
-  if (loop->depth == 1 && !loop->clobber_loop1)
+  if (loop->depth == 1 && !clobber1)
     {
-      lc_reg = reg_lc1;
-      lt_reg = reg_lt1;
-      lb_reg = reg_lb1;
-      loop->clobber_loop1 = 1;
+      lc_reg = gen_rtx_REG (SImode, REG_LC1);
+      lb_reg = gen_rtx_REG (SImode, REG_LB1);
+      lt_reg = gen_rtx_REG (SImode, REG_LT1);
+      SET_HARD_REG_BIT (loop->regs_set_in_loop, REG_LC1);
     }
   else
     {
-      lc_reg = reg_lc0;
-      lt_reg = reg_lt0;
-      lb_reg = reg_lb0;
-      loop->clobber_loop0 = 1;
+      lc_reg = gen_rtx_REG (SImode, REG_LC0);
+      lb_reg = gen_rtx_REG (SImode, REG_LB0);
+      lt_reg = gen_rtx_REG (SImode, REG_LT0);
+      SET_HARD_REG_BIT (loop->regs_set_in_loop, REG_LC0);
     }
 
   loop->end_label = end_label;
@@ -4009,15 +3795,17 @@ bfin_optimize_loop (loop_info loop)
   /* Insert the loop end label before the last instruction of the loop.  */
   emit_label_before (loop->end_label, loop->last_insn);
 
-  return;
-
- bad_loop:
-
-  if (dump_file)
-    fprintf (dump_file, ";; loop %d is bad\n", loop->loop_no);
-
-  loop->bad = 1;
+  return true;
+}
 
+/* A callback for the hw-doloop pass.  Called when a loop we have discovered
+   turns out not to be optimizable; we have to split the doloop_end pattern
+   into a subtract and a test.  */
+static void
+hwloop_fail (hwloop_info loop)
+{
+  rtx insn = loop->loop_end;
+  
   if (DPREG_P (loop->iter_reg))
     {
       /* If loop->iter_reg is a DREG or PREG, we can split it here
@@ -4039,369 +3827,39 @@ bfin_optimize_loop (loop_info loop)
       LABEL_NUSES (loop->start_label)++;
       delete_insn (loop->loop_end);
     }
-}
-
-/* Called from bfin_reorg_loops when a potential loop end is found.  LOOP is
-   a newly set up structure describing the loop, it is this function's
-   responsibility to fill most of it.  TAIL_BB and TAIL_INSN point to the
-   loop_end insn and its enclosing basic block.  */
-
-static void
-bfin_discover_loop (loop_info loop, basic_block tail_bb, rtx tail_insn)
-{
-  unsigned dwork = 0;
-  basic_block bb;
-  VEC (basic_block,heap) *works = VEC_alloc (basic_block,heap,20);
-
-  loop->tail = tail_bb;
-  loop->head = BRANCH_EDGE (tail_bb)->dest;
-  loop->successor = FALLTHRU_EDGE (tail_bb)->dest;
-  loop->loop_end = tail_insn;
-  loop->last_insn = NULL_RTX;
-  loop->iter_reg = SET_DEST (XVECEXP (PATTERN (tail_insn), 0, 1));
-  loop->depth = loop->length = 0;
-  loop->visited = 0;
-  loop->clobber_loop0 = loop->clobber_loop1 = 0;
-  loop->outer = NULL;
-  loop->loops = NULL;
-  loop->incoming = VEC_alloc (edge, gc, 2);
-  loop->start_label = XEXP (XEXP (SET_SRC (XVECEXP (PATTERN (tail_insn), 0, 0)), 1), 0);
-  loop->end_label = NULL_RTX;
-  loop->bad = 0;
-
-  VEC_safe_push (basic_block, heap, works, loop->head);
-
-  while (VEC_iterate (basic_block, works, dwork++, bb))
-    {
-      edge e;
-      edge_iterator ei;
-      if (bb == EXIT_BLOCK_PTR)
-	{
-	  /* We've reached the exit block.  The loop must be bad. */
-	  if (dump_file)
-	    fprintf (dump_file,
-		     ";; Loop is bad - reached exit block while scanning\n");
-	  loop->bad = 1;
-	  break;
-	}
-
-      if (!bitmap_set_bit (loop->block_bitmap, bb->index))
-	continue;
-
-      /* We've not seen this block before.  Add it to the loop's
-	 list and then add each successor to the work list.  */
-
-      VEC_safe_push (basic_block, heap, loop->blocks, bb);
-
-      if (bb != tail_bb)
-	{
-	  FOR_EACH_EDGE (e, ei, bb->succs)
-	    {
-	      basic_block succ = EDGE_SUCC (bb, ei.index)->dest;
-	      if (!REGNO_REG_SET_P (df_get_live_in (succ),
-				    REGNO (loop->iter_reg)))
-		continue;
-	      if (!VEC_space (basic_block, works, 1))
-		{
-		  if (dwork)
-		    {
-		      VEC_block_remove (basic_block, works, 0, dwork);
-		      dwork = 0;
-		    }
-		  else
-		    VEC_reserve (basic_block, heap, works, 1);
-		}
-	      VEC_quick_push (basic_block, works, succ);
-	    }
-	}
-    }
-
-  /* Find the predecessor, and make sure nothing else jumps into this loop.  */
-  if (!loop->bad)
+  else
     {
-      int pass, retry;
-      FOR_EACH_VEC_ELT (basic_block, loop->blocks, dwork, bb)
-	{
-	  edge e;
-	  edge_iterator ei;
-	  FOR_EACH_EDGE (e, ei, bb->preds)
-	    {
-	      basic_block pred = e->src;
-
-	      if (!bfin_bb_in_loop (loop, pred))
-		{
-		  if (dump_file)
-		    fprintf (dump_file, ";; Loop %d: incoming edge %d -> %d\n",
-			     loop->loop_no, pred->index,
-			     e->dest->index);
-		  VEC_safe_push (edge, gc, loop->incoming, e);
-		}
-	    }
-	}
-
-      for (pass = 0, retry = 1; retry && pass < 2; pass++)
-	{
-	  edge e;
-	  edge_iterator ei;
-	  bool first = true;
-	  retry = 0;
-
-	  FOR_EACH_EDGE (e, ei, loop->incoming)
-	    {
-	      if (first)
-		{
-		  loop->incoming_src = e->src;
-		  loop->incoming_dest = e->dest;
-		  first = false;
-		}
-	      else
-		{
-		  if (e->dest != loop->incoming_dest)
-		    loop->incoming_dest = NULL;
-		  if (e->src != loop->incoming_src)
-		    loop->incoming_src = NULL;
-		}
-	      if (loop->incoming_src == NULL && loop->incoming_dest == NULL)
-		{
-		  if (pass == 0)
-		    {
-		      if (dump_file)
-			fprintf (dump_file,
-				 ";; retrying loop %d with forwarder blocks\n",
-				 loop->loop_no);
-		      retry = 1;
-		      break;
-		    }
-		  loop->bad = 1;
-		  if (dump_file)
-		    fprintf (dump_file,
-			     ";; can't find suitable entry for loop %d\n",
-			     loop->loop_no);
-		  goto out;
-		}
-	    }
-	  if (retry)
-	    {
-	      retry = 0;
-	      FOR_EACH_EDGE (e, ei, loop->incoming)
-		{
-		  if (forwarder_block_p (e->src))
-		    {
-		      edge e2;
-		      edge_iterator ei2;
-
-		      if (dump_file)
-			fprintf (dump_file,
-				 ";; Adding forwarder block %d to loop %d and retrying\n",
-				 e->src->index, loop->loop_no);
-		      VEC_safe_push (basic_block, heap, loop->blocks, e->src);
-		      bitmap_set_bit (loop->block_bitmap, e->src->index);
-		      FOR_EACH_EDGE (e2, ei2, e->src->preds)
-			VEC_safe_push (edge, gc, loop->incoming, e2);
-		      VEC_unordered_remove (edge, loop->incoming, ei.index);
-		      retry = 1;
-		      break;
-		    }
-		}
-	      if (!retry)
-		{
-		  if (dump_file)
-		    fprintf (dump_file, ";; No forwarder blocks found\n");
-		  loop->bad = 1;
-		}
-	    }
-	}
+      splitting_loops = 1;  
+      try_split (PATTERN (insn), insn, 1);
+      splitting_loops = 0;
     }
-
- out:
-  VEC_free (basic_block, heap, works);
 }
 
-/* Analyze the structure of the loops in the current function.  Use STACK
-   for bitmap allocations.  Returns all the valid candidates for hardware
-   loops found in this function.  */
-static loop_info
-bfin_discover_loops (bitmap_obstack *stack, FILE *dump_file)
-{
-  loop_info loops = NULL;
-  loop_info loop;
-  basic_block bb;
-  bitmap tmp_bitmap;
-  int nloops = 0;
+/* A callback for the hw-doloop pass.  This function examines INSN; if
+   it is a loop_end pattern we recognize, return the reg rtx for the
+   loop counter.  Otherwise, return NULL_RTX.  */
 
-  /* Find all the possible loop tails.  This means searching for every
-     loop_end instruction.  For each one found, create a loop_info
-     structure and add the head block to the work list. */
-  FOR_EACH_BB (bb)
-    {
-      rtx tail = BB_END (bb);
-
-      while (GET_CODE (tail) == NOTE)
-	tail = PREV_INSN (tail);
-
-      bb->aux = NULL;
-
-      if (INSN_P (tail) && recog_memoized (tail) == CODE_FOR_loop_end)
-	{
-	  rtx insn;
-	  /* A possible loop end */
-
-	  /* There's a degenerate case we can handle - an empty loop consisting
-	     of only a back branch.  Handle that by deleting the branch.  */
-	  insn = BB_HEAD (BRANCH_EDGE (bb)->dest);
-	  if (next_real_insn (insn) == tail)
-	    {
-	      if (dump_file)
-		{
-		  fprintf (dump_file, ";; degenerate loop ending at\n");
-		  print_rtl_single (dump_file, tail);
-		}
-	      delete_insn_and_edges (tail);
-	      continue;
-	    }
-
-	  loop = XNEW (struct loop_info_d);
-	  loop->next = loops;
-	  loops = loop;
-	  loop->loop_no = nloops++;
-	  loop->blocks = VEC_alloc (basic_block, heap, 20);
-	  loop->block_bitmap = BITMAP_ALLOC (stack);
-	  bb->aux = loop;
-
-	  if (dump_file)
-	    {
-	      fprintf (dump_file, ";; potential loop %d ending at\n",
-		       loop->loop_no);
-	      print_rtl_single (dump_file, tail);
-	    }
-
-	  bfin_discover_loop (loop, bb, tail);
-	}
-    }
-
-  tmp_bitmap = BITMAP_ALLOC (stack);
-  /* Compute loop nestings.  */
-  for (loop = loops; loop; loop = loop->next)
-    {
-      loop_info other;
-      if (loop->bad)
-	continue;
-
-      for (other = loop->next; other; other = other->next)
-	{
-	  if (other->bad)
-	    continue;
-
-	  bitmap_and (tmp_bitmap, other->block_bitmap, loop->block_bitmap);
-	  if (bitmap_empty_p (tmp_bitmap))
-	    continue;
-	  if (bitmap_equal_p (tmp_bitmap, other->block_bitmap))
-	    {
-	      other->outer = loop;
-	      VEC_safe_push (loop_info, heap, loop->loops, other);
-	    }
-	  else if (bitmap_equal_p (tmp_bitmap, loop->block_bitmap))
-	    {
-	      loop->outer = other;
-	      VEC_safe_push (loop_info, heap, other->loops, loop);
-	    }
-	  else
-	    {
-	      if (dump_file)
-		fprintf (dump_file,
-			 ";; can't find suitable nesting for loops %d and %d\n",
-			 loop->loop_no, other->loop_no);
-	      loop->bad = other->bad = 1;
-	    }
-	}
-    }
-  BITMAP_FREE (tmp_bitmap);
+static rtx
+hwloop_pattern_reg (rtx insn)
+{
+  rtx pat, reg;
 
-  return loops;
-}
+  if (!JUMP_P (insn) || recog_memoized (insn) != CODE_FOR_loop_end)
+    return NULL_RTX;
 
-/* Free up the loop structures in LOOPS.  */
-static void
-free_loops (loop_info loops)
-{
-  while (loops)
-    {
-      loop_info loop = loops;
-      loops = loop->next;
-      VEC_free (loop_info, heap, loop->loops);
-      VEC_free (basic_block, heap, loop->blocks);
-      BITMAP_FREE (loop->block_bitmap);
-      XDELETE (loop);
-    }
+  pat = PATTERN (insn);
+  reg = SET_DEST (XVECEXP (PATTERN (insn), 0, 1));
+  if (!REG_P (reg))
+    return NULL_RTX;
+  return reg;
 }
 
-#define BB_AUX_INDEX(BB) ((intptr_t)(BB)->aux)
-
-/* The taken-branch edge from the loop end can actually go forward.  Since the
-   Blackfin's LSETUP instruction requires that the loop end be after the loop
-   start, try to reorder a loop's basic blocks when we find such a case.  */
-static void
-bfin_reorder_loops (loop_info loops, FILE *dump_file)
+static struct hw_doloop_hooks bfin_doloop_hooks =
 {
-  basic_block bb;
-  loop_info loop;
-
-  FOR_EACH_BB (bb)
-    bb->aux = NULL;
-  cfg_layout_initialize (0);
-
-  for (loop = loops; loop; loop = loop->next)
-    {
-      intptr_t index;
-      basic_block bb;
-      edge e;
-      edge_iterator ei;
-
-      if (loop->bad)
-	continue;
-
-      /* Recreate an index for basic blocks that represents their order.  */
-      for (bb = ENTRY_BLOCK_PTR->next_bb, index = 0;
-	   bb != EXIT_BLOCK_PTR;
-	   bb = bb->next_bb, index++)
-	bb->aux = (PTR) index;
-
-      if (BB_AUX_INDEX (loop->head) < BB_AUX_INDEX (loop->tail))
-	continue;
-
-      FOR_EACH_EDGE (e, ei, loop->head->succs)
-	{
-	  if (bitmap_bit_p (loop->block_bitmap, e->dest->index)
-	      && BB_AUX_INDEX (e->dest) < BB_AUX_INDEX (loop->tail))
-	    {
-	      basic_block start_bb = e->dest;
-	      basic_block start_prev_bb = start_bb->prev_bb;
-
-	      if (dump_file)
-		fprintf (dump_file, ";; Moving block %d before block %d\n",
-			 loop->head->index, start_bb->index);
-	      loop->head->prev_bb->next_bb = loop->head->next_bb;
-	      loop->head->next_bb->prev_bb = loop->head->prev_bb;
-
-	      loop->head->prev_bb = start_prev_bb;
-	      loop->head->next_bb = start_bb;
-	      start_prev_bb->next_bb = start_bb->prev_bb = loop->head;
-	      break;
-	    }
-	}
-      loops = loops->next;
-    }
-  
-  FOR_EACH_BB (bb)
-    {
-      if (bb->next_bb != EXIT_BLOCK_PTR)
-	bb->aux = bb->next_bb;
-      else
-	bb->aux = NULL;
-    }
-  cfg_layout_finalize ();
-  df_analyze ();
-}
+  hwloop_pattern_reg,
+  hwloop_optimize,
+  hwloop_fail
+};
 
 /* Run from machine_dependent_reorg, this pass looks for doloop_end insns
    and tries to rewrite the RTL of these loops so that proper Blackfin
@@ -4410,62 +3868,7 @@ bfin_reorder_loops (loop_info loops, FILE *dump_file)
 static void
 bfin_reorg_loops (FILE *dump_file)
 {
-  loop_info loops = NULL;
-  loop_info loop;
-  basic_block bb;
-  bitmap_obstack stack;
-
-  bitmap_obstack_initialize (&stack);
-
-  if (dump_file)
-    fprintf (dump_file, ";; Find loops, first pass\n\n");
-
-  loops = bfin_discover_loops (&stack, dump_file);
-
-  if (dump_file)
-    bfin_dump_loops (loops);
-
-  bfin_reorder_loops (loops, dump_file);
-  free_loops (loops);
-
-  if (dump_file)
-    fprintf (dump_file, ";; Find loops, second pass\n\n");
-
-  loops = bfin_discover_loops (&stack, dump_file);
-  if (dump_file)
-    {
-      fprintf (dump_file, ";; All loops found:\n\n");
-      bfin_dump_loops (loops);
-    }
-
-  /* Now apply the optimizations.  */
-  for (loop = loops; loop; loop = loop->next)
-    bfin_optimize_loop (loop);
-
-  if (dump_file)
-    {
-      fprintf (dump_file, ";; After hardware loops optimization:\n\n");
-      bfin_dump_loops (loops);
-    }
-
-  free_loops (loops);
-
-  if (dump_file)
-    print_rtl (dump_file, get_insns ());
-
-  FOR_EACH_BB (bb)
-    bb->aux = NULL;
-
-  splitting_loops = 1;
-  FOR_EACH_BB (bb)
-    {
-      rtx insn = BB_END (bb);
-      if (!JUMP_P (insn))
-	continue;
-
-      try_split (PATTERN (insn), insn, 1);
-    }
-  splitting_loops = 0;
+  reorg_loops (true, &bfin_doloop_hooks);
 }
 
 /* Possibly generate a SEQUENCE out of three insns found in SLOT.
diff --git a/gcc/config/bfin/bfin.md b/gcc/config/bfin/bfin.md
index a96d1a7..8d8413d 100644
--- a/gcc/config/bfin/bfin.md
+++ b/gcc/config/bfin/bfin.md
@@ -1993,7 +1993,7 @@
 	      (const_int -1)))
    (unspec [(const_int 0)] UNSPEC_LSETUP_END)
    (clobber (match_scratch:SI 2 "=&r"))]
-  "splitting_loops"
+  "memory_operand (operands[0], SImode) || splitting_loops"
   [(set (match_dup 2) (match_dup 0))
    (set (match_dup 2) (plus:SI (match_dup 2) (const_int -1)))
    (set (match_dup 0) (match_dup 2))
diff --git a/gcc/hw-doloop.c b/gcc/hw-doloop.c
new file mode 100644
index 0000000..3d59200
--- /dev/null
+++ b/gcc/hw-doloop.c
@@ -0,0 +1,672 @@
+/* Code to analyze doloop loops in order for targets to perform late
+   optimizations converting doloops to other forms of hardware loops.
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "flags.h"
+#include "expr.h"
+#include "hard-reg-set.h"
+#include "regs.h"
+#include "basic-block.h"
+#include "tm_p.h"
+#include "df.h"
+#include "cfglayout.h"
+#include "cfgloop.h"
+#include "output.h"
+#include "recog.h"
+#include "target.h"
+#include "hw-doloop.h"
+
+#ifdef HAVE_doloop_end
+
+/* Dump information collected in LOOPS.  */
+static void
+dump_hwloops (hwloop_info loops)
+{
+  hwloop_info loop;
+
+  for (loop = loops; loop; loop = loop->next)
+    {
+      hwloop_info i;
+      basic_block b;
+      unsigned ix;
+
+      fprintf (dump_file, ";; loop %d: ", loop->loop_no);
+      if (loop->bad)
+	fprintf (dump_file, "(bad) ");
+      fprintf (dump_file, "{head:%d, depth:%d, reg:%u}",
+	       loop->head == NULL ? -1 : loop->head->index,
+	       loop->depth, REGNO (loop->iter_reg));
+
+      fprintf (dump_file, " blocks: [ ");
+      for (ix = 0; VEC_iterate (basic_block, loop->blocks, ix, b); ix++)
+	fprintf (dump_file, "%d ", b->index);
+      fprintf (dump_file, "] ");
+
+      fprintf (dump_file, " inner loops: [ ");
+      for (ix = 0; VEC_iterate (hwloop_info, loop->loops, ix, i); ix++)
+	fprintf (dump_file, "%d ", i->loop_no);
+      fprintf (dump_file, "]\n");
+    }
+  fprintf (dump_file, "\n");
+}
+
+/* Return true if BB is part of LOOP.  */
+static bool
+bb_in_loop_p (hwloop_info loop, basic_block bb)
+{
+  return bitmap_bit_p (loop->block_bitmap, bb->index);
+}
+
+/* Scan the blocks of LOOP (and its inferiors), and record things such as
+   hard registers set, jumps out of and within the loop.  */
+static void
+scan_loop (hwloop_info loop)
+{
+  unsigned ix;
+  basic_block bb;
+
+  if (loop->bad)
+    return;
+
+  if (REGNO_REG_SET_P (df_get_live_in (loop->successor),
+		       REGNO (loop->iter_reg)))
+    loop->iter_reg_used_outside = true;
+
+  for (ix = 0; VEC_iterate (basic_block, loop->blocks, ix, bb); ix++)
+    {
+      rtx insn;
+      edge e;
+      edge_iterator ei;
+
+      if (bb != loop->tail)
+	FOR_EACH_EDGE (e, ei, bb->succs)
+	  {
+	    if (bb_in_loop_p (loop, e->dest))
+	      {
+		if (!(e->flags & EDGE_FALLTHRU))
+		  loop->jumps_within = true;
+	      }
+	    else
+	      {
+		loop->jumps_outof = true;
+		if (!loop->bad)
+		  gcc_assert (!REGNO_REG_SET_P (df_get_live_in (e->dest),
+						REGNO (loop->iter_reg)));
+	      }
+	  }
+
+      for (insn = BB_HEAD (bb);
+	   insn != NEXT_INSN (BB_END (bb));
+	   insn = NEXT_INSN (insn))
+	{
+	  df_ref *def_rec;
+	  HARD_REG_SET set_this_insn;
+
+	  if (!INSN_P (insn))
+	    continue;
+
+	  if (recog_memoized (insn) < 0
+	      && (GET_CODE (PATTERN (insn)) == ASM_INPUT
+		  || asm_noperands (PATTERN (insn)) >= 0))
+	    loop->has_asm = true;
+
+	  CLEAR_HARD_REG_SET (set_this_insn);
+	  for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
+	    {
+	      rtx dreg = DF_REF_REG (*def_rec);
+
+	      if (!REG_P (dreg))
+		continue;
+
+	      add_to_hard_reg_set (&set_this_insn, GET_MODE (dreg),
+				   REGNO (dreg));
+	    }
+
+	  if (insn == loop->loop_end)
+	    CLEAR_HARD_REG_BIT (set_this_insn, REGNO (loop->iter_reg));
+	  else if (reg_mentioned_p (loop->iter_reg, PATTERN (insn)))
+	    loop->iter_reg_used = true;
+	  IOR_HARD_REG_SET (loop->regs_set_in_loop, set_this_insn);
+	}
+    }
+}
+
+/* Compute the incoming_dest and incoming_src members of LOOP by
+   identifying the edges that jump into the loop.  If there is more
+   than one block that jumps into the loop, incoming_src will be set
+   to NULL; likewise, if there is more than one block in the loop that
+   is the destination of an incoming edge, incoming_dest will be NULL.
+
+   Return true if either of these two fields is nonnull, false
+   otherwise.  */
+static bool
+process_incoming_edges (hwloop_info loop)
+{
+  edge e;
+  edge_iterator ei;
+  bool first = true;
+
+  FOR_EACH_EDGE (e, ei, loop->incoming)
+    {
+      if (first)
+	{
+	  loop->incoming_src = e->src;
+	  loop->incoming_dest = e->dest;
+	  first = false;
+	}
+      else
+	{
+	  if (e->dest != loop->incoming_dest)
+	    loop->incoming_dest = NULL;
+	  if (e->src != loop->incoming_src)
+	    loop->incoming_src = NULL;
+	}
+    }
+  if (loop->incoming_src == NULL && loop->incoming_dest == NULL)
+    return false;
+
+  return true;
+}
+
+/* Try to identify a forwarder block that jump into LOOP, and add it to
+   the set of blocks in the loop, updating the vector of incoming blocks as
+   well.  This transformation gives a second chance to loops we couldn't
+   otherwise handle by increasing the chance that we'll end up with one
+   incoming_src block.
+   Return true if we made a change, false otherwise.  */
+static bool
+add_forwarder_blocks (hwloop_info loop)
+{
+  edge e;
+  edge_iterator ei;
+
+  FOR_EACH_EDGE (e, ei, loop->incoming)
+    {
+      if (forwarder_block_p (e->src))
+	{
+	  edge e2;
+	  edge_iterator ei2;
+
+	  if (dump_file)
+	    fprintf (dump_file,
+		     ";; Adding forwarder block %d to loop %d and retrying\n",
+		     e->src->index, loop->loop_no);
+	  VEC_safe_push (basic_block, heap, loop->blocks, e->src);
+	  bitmap_set_bit (loop->block_bitmap, e->src->index);
+	  FOR_EACH_EDGE (e2, ei2, e->src->preds)
+	    VEC_safe_push (edge, gc, loop->incoming, e2);
+	  VEC_unordered_remove (edge, loop->incoming, ei.index);
+	  return true;
+	}
+    }
+  return false;
+}
+
+/* Called from reorg_loops when a potential loop end is found.  LOOP is
+   a newly set up structure describing the loop, it is this function's
+   responsibility to fill most of it.  TAIL_BB and TAIL_INSN point to the
+   loop_end insn and its enclosing basic block.  REG is the loop counter
+   register.
+   For our purposes, a loop is defined by the set of blocks reachable from
+   the loop head in which the loop counter register is live.  This matches
+   the expected use; targets that call into this code usually replace the
+   loop counter with a different special register.  */
+static void
+discover_loop (hwloop_info loop, basic_block tail_bb, rtx tail_insn, rtx reg)
+{
+  bool found_tail;
+  unsigned dwork = 0;
+  basic_block bb;
+  VEC (basic_block,heap) *works;
+
+  loop->tail = tail_bb;
+  loop->loop_end = tail_insn;
+  loop->iter_reg = reg;
+  loop->incoming = VEC_alloc (edge, gc, 2);
+  loop->start_label = JUMP_LABEL (tail_insn);
+
+  if (EDGE_COUNT (tail_bb->succs) != 2)
+    {
+      loop->bad = true;
+      return;
+    }
+  loop->head = BRANCH_EDGE (tail_bb)->dest;
+  loop->successor = FALLTHRU_EDGE (tail_bb)->dest;
+
+  works = VEC_alloc (basic_block, heap, 20);
+  VEC_safe_push (basic_block, heap, works, loop->head);
+
+  found_tail = false;
+  for (dwork = 0; VEC_iterate (basic_block, works, dwork, bb); dwork++)
+    {
+      edge e;
+      edge_iterator ei;
+      if (bb == EXIT_BLOCK_PTR)
+	{
+	  /* We've reached the exit block.  The loop must be bad. */
+	  if (dump_file)
+	    fprintf (dump_file,
+		     ";; Loop is bad - reached exit block while scanning\n");
+	  loop->bad = true;
+	  break;
+	}
+
+      if (bitmap_bit_p (loop->block_bitmap, bb->index))
+	continue;
+
+      /* We've not seen this block before.  Add it to the loop's
+	 list and then add each successor to the work list.  */
+
+      VEC_safe_push (basic_block, heap, loop->blocks, bb);
+      bitmap_set_bit (loop->block_bitmap, bb->index);
+
+      if (bb == tail_bb)
+	found_tail = true;
+      else
+	{
+	  FOR_EACH_EDGE (e, ei, bb->succs)
+	    {
+	      basic_block succ = EDGE_SUCC (bb, ei.index)->dest;
+	      if (REGNO_REG_SET_P (df_get_live_in (succ),
+				   REGNO (loop->iter_reg)))
+		VEC_safe_push (basic_block, heap, works, succ);
+	    }
+	}
+    }
+
+  if (!found_tail)
+    loop->bad = true;
+  
+  /* Find the predecessor, and make sure nothing else jumps into this loop.  */
+  if (!loop->bad)
+    {
+      FOR_EACH_VEC_ELT (basic_block, loop->blocks, dwork, bb)
+	{
+	  edge e;
+	  edge_iterator ei;
+	  FOR_EACH_EDGE (e, ei, bb->preds)
+	    {
+	      basic_block pred = e->src;
+
+	      if (!bb_in_loop_p (loop, pred))
+		{
+		  if (dump_file)
+		    fprintf (dump_file, ";; Loop %d: incoming edge %d -> %d\n",
+			     loop->loop_no, pred->index,
+			     e->dest->index);
+		  VEC_safe_push (edge, gc, loop->incoming, e);
+		}
+	    }
+	}
+
+      if (!process_incoming_edges (loop))
+	{
+	  if (dump_file)
+	    fprintf (dump_file,
+		     ";; retrying loop %d with forwarder blocks\n",
+		     loop->loop_no);
+	  if (!add_forwarder_blocks (loop))
+	    {
+	      if (dump_file)
+		fprintf (dump_file, ";; No forwarder blocks found\n");
+	      loop->bad = true;
+	    }
+	  else if (!process_incoming_edges (loop))
+	    {
+	      if (dump_file)
+		fprintf (dump_file,
+			 ";; can't find suitable entry for loop %d\n",
+			 loop->loop_no);
+	    }
+	}
+    }
+
+  VEC_free (basic_block, heap, works);
+}
+
+/* Analyze the structure of the loops in the current function.  Use
+   STACK for bitmap allocations.  Returns all the valid candidates for
+   hardware loops found in this function.  HOOKS is the argument
+   passed to reorg_loops, used here to find the iteration registers
+   from a loop_end pattern.  */
+static hwloop_info
+discover_loops (bitmap_obstack *stack, struct hw_doloop_hooks *hooks)
+{
+  hwloop_info loops = NULL;
+  hwloop_info loop;
+  basic_block bb;
+  int nloops = 0;
+
+  /* Find all the possible loop tails.  This means searching for every
+     loop_end instruction.  For each one found, create a hwloop_info
+     structure and add the head block to the work list. */
+  FOR_EACH_BB (bb)
+    {
+      rtx tail = BB_END (bb);
+      rtx insn, reg;
+
+      while (tail && GET_CODE (tail) == NOTE && tail != BB_HEAD (bb))
+	tail = PREV_INSN (tail);
+
+      if (tail == NULL_RTX)
+	continue;
+
+      if (!JUMP_P (tail))
+	continue;
+      reg = hooks->end_pattern_reg (tail);
+      if (reg == NULL_RTX)
+	continue;
+
+      /* A possible loop end */
+
+      /* There's a degenerate case we can handle - an empty loop consisting
+	 of only a back branch.  Handle that by deleting the branch.  */
+      insn = JUMP_LABEL (tail);
+      while (insn && !NONDEBUG_INSN_P (insn))
+	insn = NEXT_INSN (insn);
+      if (insn == tail)
+	{
+	  basic_block succ = FALLTHRU_EDGE (bb)->dest;
+	  if (dump_file)
+	    {
+	      fprintf (dump_file, ";; degenerate loop ending at\n");
+	      print_rtl_single (dump_file, tail);
+	    }
+	  if (!REGNO_REG_SET_P (df_get_live_in (succ), REGNO (reg)))
+	    {
+	      if (dump_file)
+		fprintf (dump_file, ";; deleting it\n");
+	      delete_insn_and_edges (tail);
+	      continue;
+	    }
+	}
+
+      loop = XCNEW (struct hwloop_info_d);
+      loop->next = loops;
+      loops = loop;
+      loop->loop_no = nloops++;
+      loop->blocks = VEC_alloc (basic_block, heap, 20);
+      loop->block_bitmap = BITMAP_ALLOC (stack);
+
+      if (dump_file)
+	{
+	  fprintf (dump_file, ";; potential loop %d ending at\n",
+		   loop->loop_no);
+	  print_rtl_single (dump_file, tail);
+	}
+
+      discover_loop (loop, bb, tail, reg);
+    }
+
+  /* Compute loop nestings.  Given two loops A and B, either the sets
+     of their blocks don't intersect at all, or one is the subset of
+     the other, or the blocks don't form a good nesting structure.  */
+  for (loop = loops; loop; loop = loop->next)
+    {
+      hwloop_info other;
+
+      if (loop->bad)
+	continue;
+
+      for (other = loops; other; other = other->next)
+	{
+	  if (other->bad)
+	    continue;
+
+	  if (!bitmap_intersect_p (other->block_bitmap, loop->block_bitmap))
+	    continue;
+	  if (!bitmap_intersect_compl_p (other->block_bitmap,
+					 loop->block_bitmap))
+	    VEC_safe_push (hwloop_info, heap, loop->loops, other);
+	  else if (!bitmap_intersect_compl_p (loop->block_bitmap,
+					      other->block_bitmap))
+	    VEC_safe_push (hwloop_info, heap, other->loops, loop);
+	  else
+	    {
+	      if (dump_file)
+		fprintf (dump_file,
+			 ";; can't find suitable nesting for loops %d and %d\n",
+			 loop->loop_no, other->loop_no);
+	      loop->bad = other->bad = true;
+	    }
+	}
+    }
+
+  if (dump_file)
+    dump_hwloops (loops);
+
+  return loops;
+}
+
+/* Free up the loop structures in LOOPS.  */
+static void
+free_loops (hwloop_info loops)
+{
+  while (loops)
+    {
+      hwloop_info loop = loops;
+      loops = loop->next;
+      VEC_free (hwloop_info, heap, loop->loops);
+      VEC_free (basic_block, heap, loop->blocks);
+      BITMAP_FREE (loop->block_bitmap);
+      XDELETE (loop);
+    }
+}
+
+#define BB_AUX_INDEX(BB) ((intptr_t) (BB)->aux)
+
+/* Initialize the aux fields to give ascending indices to basic blocks.  */
+static void
+set_bb_indices (void)
+{
+  basic_block bb;
+  intptr_t index;
+
+  index = 0;
+  FOR_EACH_BB (bb)
+    bb->aux = (void *) index++;
+}
+
+/* The taken-branch edge from the loop end can actually go forward.
+   If the target's hardware loop support requires that the loop end be
+   after the loop start, try to reorder a loop's basic blocks when we
+   find such a case.
+   This is not very aggressive; it only moves at most one block.  It
+   does not introduce new branches into loops; it may remove them, or
+   it may switch fallthru/jump edges.  */
+static void
+reorder_loops (hwloop_info loops)
+{
+  basic_block bb;
+  hwloop_info loop;
+
+  cfg_layout_initialize (0);
+
+  set_bb_indices ();
+
+  for (loop = loops; loop; loop = loop->next)
+    {
+      edge e;
+      edge_iterator ei;
+
+      if (loop->bad)
+	continue;
+
+      if (BB_AUX_INDEX (loop->head) <= BB_AUX_INDEX (loop->tail))
+	continue;
+
+      FOR_EACH_EDGE (e, ei, loop->head->succs)
+	{
+	  if (bitmap_bit_p (loop->block_bitmap, e->dest->index)
+	      && BB_AUX_INDEX (e->dest) < BB_AUX_INDEX (loop->tail))
+	    {
+	      basic_block start_bb = e->dest;
+	      basic_block start_prev_bb = start_bb->prev_bb;
+
+	      if (dump_file)
+		fprintf (dump_file, ";; Moving block %d before block %d\n",
+			 loop->head->index, start_bb->index);
+	      loop->head->prev_bb->next_bb = loop->head->next_bb;
+	      loop->head->next_bb->prev_bb = loop->head->prev_bb;
+
+	      loop->head->prev_bb = start_prev_bb;
+	      loop->head->next_bb = start_bb;
+	      start_prev_bb->next_bb = start_bb->prev_bb = loop->head;
+
+	      set_bb_indices ();
+	      break;
+	    }
+	}
+      loops = loops->next;
+    }
+  
+  FOR_EACH_BB (bb)
+    {
+      if (bb->next_bb != EXIT_BLOCK_PTR)
+	bb->aux = bb->next_bb;
+      else
+	bb->aux = NULL;
+    }
+  cfg_layout_finalize ();
+  clear_aux_for_blocks ();
+  df_analyze ();
+}
+
+/* Call the OPT function for LOOP and all of its sub-loops.  This is
+   done in a depth-first search; innermost loops are visited first.
+   OPTIMIZE and FAIL are the functions passed to reorg_loops by the
+   target's reorg pass.  */
+static void
+optimize_loop (hwloop_info loop, struct hw_doloop_hooks *hooks)
+{
+  int ix;
+  hwloop_info inner;
+  int inner_depth = 0;
+
+  if (loop->visited)
+    return;
+
+  loop->visited = 1;
+
+  if (loop->bad)
+    {
+      if (dump_file)
+	fprintf (dump_file, ";; loop %d bad when found\n", loop->loop_no);
+      goto bad_loop;
+    }
+
+  /* Every loop contains in its list of inner loops every loop nested inside
+     it, even if there are intermediate loops.  This works because we're doing
+     a depth-first search here and never visit a loop more than once.
+     Recursion depth is effectively limited by the number of available
+     hardware registers.  */
+  for (ix = 0; VEC_iterate (hwloop_info, loop->loops, ix, inner); ix++)
+    {
+      optimize_loop (inner, hooks);
+
+      if (!inner->bad && inner_depth < inner->depth)
+	inner_depth = inner->depth;
+      /* The set of registers may be changed while optimizing the inner
+	 loop.  */
+      IOR_HARD_REG_SET (loop->regs_set_in_loop, inner->regs_set_in_loop);
+    }
+
+  loop->depth = inner_depth + 1;
+
+  if (hooks->opt (loop))
+    return;
+
+ bad_loop:
+  if (dump_file)
+    fprintf (dump_file, ";; loop %d is bad\n", loop->loop_no);
+
+  loop->bad = true;
+  hooks->fail (loop);
+}
+
+/* This function can be used from a port's machine_dependent_reorg to
+   find and analyze loops that end in loop_end instructions.  It uses
+   a set of function pointers in HOOKS to call back into the
+   target-specific functions to perform the actual machine-specific
+   transformations.
+
+   Such transformations typically involve additional set-up
+   instructions before the loop, to define loop bounds or set up a
+   special loop counter register.
+
+   DO_REORDER should be set to true if we should try to use the
+   reorder_loops function to ensure the loop end occurs after the loop
+   start.  This is for use by targets where the loop hardware requires
+   this condition.
+
+   HOOKS is used to pass in target specific hooks; see
+   hw-doloop.h.  */
+void
+reorg_loops (bool do_reorder, struct hw_doloop_hooks *hooks)
+{
+  hwloop_info loops = NULL;
+  hwloop_info loop;
+  bitmap_obstack stack;
+
+  df_live_add_problem ();
+  df_live_set_all_dirty ();
+  df_analyze ();
+
+  bitmap_obstack_initialize (&stack);
+
+  if (dump_file)
+    fprintf (dump_file, ";; Find loops, first pass\n\n");
+
+  loops = discover_loops (&stack, hooks);
+
+  if (do_reorder)
+    {
+      reorder_loops (loops);
+      free_loops (loops);
+
+      if (dump_file)
+	fprintf (dump_file, ";; Find loops, second pass\n\n");
+
+      loops = discover_loops (&stack, hooks);
+    }
+
+  for (loop = loops; loop; loop = loop->next)
+    scan_loop (loop);
+
+  /* Now apply the optimizations.  */
+  for (loop = loops; loop; loop = loop->next)
+    optimize_loop (loop, hooks);
+
+  if (dump_file)
+    {
+      fprintf (dump_file, ";; After hardware loops optimization:\n\n");
+      dump_hwloops (loops);
+    }
+
+  free_loops (loops);
+
+  if (dump_file)
+    print_rtl (dump_file, get_insns ());
+}
+#endif
diff --git a/gcc/hw-doloop.h b/gcc/hw-doloop.h
new file mode 100644
index 0000000..006b679
--- /dev/null
+++ b/gcc/hw-doloop.h
@@ -0,0 +1,157 @@
+/* Code to analyze doloop loops in order for targets to perform late
+   optimizations converting doloops to other forms of hardware loops.
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+/* We need to keep a vector of loops */
+typedef struct hwloop_info_d *hwloop_info;
+DEF_VEC_P (hwloop_info);
+DEF_VEC_ALLOC_P (hwloop_info,heap);
+
+/* Information about a loop we have found (or are in the process of
+   finding).  */
+struct GTY (()) hwloop_info_d
+{
+  /* loop number, for dumps */
+  int loop_no;
+
+  /* Next loop in the graph. */
+  hwloop_info next;
+
+  /* Vector of blocks only within the loop, including those within
+     inner loops.  */
+  VEC (basic_block, heap) *blocks;
+
+  /* Same information in a bitmap.  */
+  bitmap block_bitmap;
+
+  /* Vector of inner loops within this loop.  Includes loops of every
+     nesting level.  */
+  VEC (hwloop_info, heap) *loops;
+
+  /* All edges that jump into the loop.  */
+  VEC(edge, gc) *incoming;
+
+  /* The ports currently using this infrastructure can typically
+     handle two cases: all incoming edges have the same destination
+     block, or all incoming edges have the same source block.  These
+     two members are set to the common source or destination we found,
+     or NULL if different blocks were found.  If both are NULL the
+     loop can't be optimized.  */
+  basic_block incoming_src;
+  basic_block incoming_dest;
+
+  /* First block in the loop.  This is the one branched to by the loop_end
+     insn.  */
+  basic_block head;
+
+  /* Last block in the loop (the one with the loop_end insn).  */
+  basic_block tail;
+
+  /* The successor block of the loop.  This is the one the loop_end insn
+     falls into.  */
+  basic_block successor;
+
+  /* The last instruction in the tail.  */
+  rtx last_insn;
+
+  /* The loop_end insn.  */
+  rtx loop_end;
+
+  /* The iteration register.  */
+  rtx iter_reg;
+
+  /* The new label placed at the beginning of the loop. */
+  rtx start_label;
+
+  /* The new label placed at the end of the loop. */
+  rtx end_label;
+
+  /* The length of the loop.  */
+  int length;
+
+  /* The nesting depth of the loop.  Innermost loops are given a depth
+     of 1.  Only successfully optimized doloops are counted; if an inner
+     loop was marked as bad, it does not increase the depth of its parent
+     loop.
+     This value is valid when the target's optimize function is called.  */
+  int depth;
+
+  /* True if we can't optimize this loop.  */
+  bool bad;
+
+  /* True if we have visited this loop during the optimization phase.  */
+  bool visited;
+
+  /* The following values are collected before calling the target's optimize
+     function and are not valid earlier.  */
+  
+  /* Record information about control flow: whether the loop has calls
+     or asm statements, whether it has edges that jump out of the loop,
+     or edges that jump within the loop.  */
+  bool has_call;
+  bool has_asm;
+  bool jumps_within;
+  bool jumps_outof;
+
+  /* True if there is an instruction other than the doloop_end which uses the
+     iteration register.  */
+  bool iter_reg_used;
+  /* True if the iteration register lives past the doloop instruction.  */
+  bool iter_reg_used_outside;
+
+  /* Hard registers set at any point in the loop, except for the loop counter
+     register's set in the doloop_end instruction.  */
+  HARD_REG_SET regs_set_in_loop;
+};
+
+/* A set of hooks to be defined by a target that wants to use the reorg_loops
+   functionality.
+
+   reorg_loops is intended to handle cases where special hardware loop
+   setup instructions are required before the loop, for example to set
+   up loop counter registers that are not exposed to the register
+   allocator, or to inform the hardware about loop bounds.
+
+   reorg_loops performs analysis to discover loop_end patterns created
+   by the earlier loop-doloop pass, and sets up a hwloop_info
+   structure for each such insn it finds.  It then tries to discover
+   the basic blocks containing the loop by tracking the lifetime of
+   the iteration register.
+
+   If a valid loop can't be found, the FAIL function is called;
+   otherwise the OPT function is called for each loop, visiting
+   innermost loops first and ascending.  */
+struct hw_doloop_hooks
+{
+  /* Examine INSN.  If it is a suitable doloop_end pattern, return the
+     iteration register, which should be a single hard register.
+     Otherwise, return NULL_RTX.  */
+  rtx (*end_pattern_reg) (rtx insn);
+  /* Optimize LOOP.  The target should perform any additional analysis
+     (e.g. checking that the loop isn't too long), and then perform
+     its transformations.  Return true if successful, false if the
+     loop should be marked bad.  If it returns false, the FAIL
+     function is called.  */
+  bool (*opt) (hwloop_info loop);
+  /* Handle a loop that was marked bad for any reason.  This could be
+     used to split the doloop_end pattern.  */
+  void (*fail) (hwloop_info loop);
+};
+
+extern void reorg_loops (bool, struct hw_doloop_hooks *);