Begin cleaning up jump.c

	Begin cleaning up jump.c
	* jump.c (init_label_info, delete_barrier_successors,
	mark_all_labels, delete_unreferenced_labels,
	delete_noop_moves, calculate_can_reach_end): New functions broken
	out of jump_optimize.
	(jump_optimize): Use them.

From-SVN: r23539

2 files changed, 457 insertions, 379 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 431f4b6..20138d4 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+Thu Nov  5 07:59:05 1998  David S. Miller  <davem@pierdol.cobaltmicro.com>
+
+	* jump.c (init_label_info, delete_barrier_successors,
+	mark_all_labels, delete_unreferenced_labels,
+	delete_noop_moves, calculate_can_reach_end): New functions broken
+	out of jump_optimize.
+	(jump_optimize): Use them.
+
 Thu Nov  5 07:57:45 EST 1998  Andrew MacLeod  <amacleod@cygnus.com>
 
 	* except.c (expand_fixup_region_end): Make sure outer context labels
diff --git a/gcc/jump.c b/gcc/jump.c
index 18696ec..cfc7f4f 100644
--- a/gcc/jump.c
+++ b/gcc/jump.c
@@ -108,6 +108,12 @@ int can_reach_end;
 
 static int cross_jump_death_matters = 0;
 
+static int init_label_info		PROTO((rtx));
+static void delete_barrier_successors	PROTO((rtx));
+static void mark_all_labels		PROTO((rtx, int));
+static rtx delete_unreferenced_labels	PROTO((rtx));
+static void delete_noop_moves		PROTO((rtx));
+static int calculate_can_reach_end	PROTO((rtx, int, int));
 static int duplicate_loop_exit_test	PROTO((rtx));
 static void find_cross_jump		PROTO((rtx, rtx, int, rtx *, rtx *));
 static void do_cross_jump		PROTO((rtx, rtx, rtx));
@@ -157,30 +163,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
   rtx last_insn;
 
   cross_jump_death_matters = (cross_jump == 2);
-
-  /* Initialize LABEL_NUSES and JUMP_LABEL fields.  Delete any REG_LABEL
-     notes whose labels don't occur in the insn any more.  */
-
-  for (insn = f; insn; insn = NEXT_INSN (insn))
-    {
-      if (GET_CODE (insn) == CODE_LABEL)
-	LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
-      else if (GET_CODE (insn) == JUMP_INSN)
-	JUMP_LABEL (insn) = 0;
-      else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
-	for (note = REG_NOTES (insn); note; note = next)
-	  {
-	    next = XEXP (note, 1);
-	    if (REG_NOTE_KIND (note) == REG_LABEL
-		&& ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
-	      remove_note (insn, note);
-	  }
-
-      if (INSN_UID (insn) > max_uid)
-	max_uid = INSN_UID (insn);
-    }
-
-  max_uid++;
+  max_uid = init_label_info (f) + 1;
 
   /* If we are performing cross jump optimizations, then initialize
      tables mapping UIDs to EH regions to avoid incorrect movement
@@ -188,26 +171,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
   if (flag_exceptions && cross_jump)
     init_insn_eh_region (f, max_uid);
 
-  /* Delete insns following barriers, up to next label.  */
-
-  for (insn = f; insn;)
-    {
-      if (GET_CODE (insn) == BARRIER)
-	{
-	  insn = NEXT_INSN (insn);
-	  while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
-	    {
-	      if (GET_CODE (insn) == NOTE
-		  && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
-		insn = NEXT_INSN (insn);
-	      else
-		insn = delete_insn (insn);
-	    }
-	  /* INSN is now the code_label.  */
-	}
-      else
-	insn = NEXT_INSN (insn);
-    }
+  delete_barrier_successors (f);
 
   /* Leave some extra room for labels and duplicate exit test insns
      we make.  */
@@ -215,32 +179,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
   jump_chain = (rtx *) alloca (max_jump_chain * sizeof (rtx));
   bzero ((char *) jump_chain, max_jump_chain * sizeof (rtx));
 
-  /* Mark the label each jump jumps to.
-     Combine consecutive labels, and count uses of labels.
-
-     For each label, make a chain (using `jump_chain')
-     of all the *unconditional* jumps that jump to it;
-     also make a chain of all returns.  */
-
-  for (insn = f; insn; insn = NEXT_INSN (insn))
-    if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
-      {
-	mark_jump_label (PATTERN (insn), insn, cross_jump);
-	if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
-	  {
-	    if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
-	      {
-		jump_chain[INSN_UID (insn)]
-		  = jump_chain[INSN_UID (JUMP_LABEL (insn))];
-		jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
-	      }
-	    if (GET_CODE (PATTERN (insn)) == RETURN)
-	      {
-		jump_chain[INSN_UID (insn)] = jump_chain[0];
-		jump_chain[0] = insn;
-	      }
-	  }
-      }
+  mark_all_labels (f, cross_jump);
 
   /* Keep track of labels used from static data;
      they cannot ever be deleted.  */
@@ -258,51 +197,11 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
 
   exception_optimize ();
 
-  /* Delete all labels already not referenced.
-     Also find the last insn.  */
-
-  last_insn = 0;
-  for (insn = f; insn; )
-    {
-      if (GET_CODE (insn) == CODE_LABEL && LABEL_NUSES (insn) == 0)
-	insn = delete_insn (insn);
-      else
-	{
-	  last_insn = insn;
-	  insn = NEXT_INSN (insn);
-	}
-    }
+  last_insn = delete_unreferenced_labels (f);
 
   if (!optimize)
     {
-      /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
-	 If so record that this function can drop off the end.  */
-
-      insn = last_insn;
-      {
-	int n_labels = 1;
-	while (insn
-	       /* One label can follow the end-note: the return label.  */
-	       && ((GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
-		   /* Ordinary insns can follow it if returning a structure.  */
-		   || GET_CODE (insn) == INSN
-		   /* If machine uses explicit RETURN insns, no epilogue,
-		      then one of them follows the note.  */
-		   || (GET_CODE (insn) == JUMP_INSN
-		       && GET_CODE (PATTERN (insn)) == RETURN)
-		   /* A barrier can follow the return insn.  */
-		   || GET_CODE (insn) == BARRIER
-		   /* Other kinds of notes can follow also.  */
-		   || (GET_CODE (insn) == NOTE
-		       && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)))
-	  insn = PREV_INSN (insn);
-      }
-
-      /* Report if control can fall through at the end of the function.  */
-      if (insn && GET_CODE (insn) == NOTE
-	  && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END
-	  && ! INSN_DELETED_P (insn))
-	can_reach_end = 1;
+      can_reach_end = calculate_can_reach_end (last_insn, 1, 0);
 
       /* Zero the "deleted" flag of all the "deleted" insns.  */
       for (insn = f; insn; insn = NEXT_INSN (insn))
@@ -333,245 +232,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
 #endif
 
   if (noop_moves)
-    for (insn = f; insn; )
-      {
-	next = NEXT_INSN (insn);
-
-	if (GET_CODE (insn) == INSN)
-	  {
-	    register rtx body = PATTERN (insn);
-
-/* Combine stack_adjusts with following push_insns.  */
-#ifdef PUSH_ROUNDING
-	    if (GET_CODE (body) == SET
-		&& SET_DEST (body) == stack_pointer_rtx
-		&& GET_CODE (SET_SRC (body)) == PLUS
-		&& XEXP (SET_SRC (body), 0) == stack_pointer_rtx
-		&& GET_CODE (XEXP (SET_SRC (body), 1)) == CONST_INT
-		&& INTVAL (XEXP (SET_SRC (body), 1)) > 0)
-	      {
-		rtx p;
-		rtx stack_adjust_insn = insn;
-		int stack_adjust_amount = INTVAL (XEXP (SET_SRC (body), 1));
-		int total_pushed = 0;
-		int pushes = 0;
-
-		/* Find all successive push insns.  */
-		p = insn;
-		/* Don't convert more than three pushes;
-		   that starts adding too many displaced addresses
-		   and the whole thing starts becoming a losing
-		   proposition.  */
-		while (pushes < 3)
-		  {
-		    rtx pbody, dest;
-		    p = next_nonnote_insn (p);
-		    if (p == 0 || GET_CODE (p) != INSN)
-		      break;
-		    pbody = PATTERN (p);
-		    if (GET_CODE (pbody) != SET)
-		      break;
-		    dest = SET_DEST (pbody);
-		    /* Allow a no-op move between the adjust and the push.  */
-		    if (GET_CODE (dest) == REG
-			&& GET_CODE (SET_SRC (pbody)) == REG
-			&& REGNO (dest) == REGNO (SET_SRC (pbody)))
-		      continue;
-		    if (! (GET_CODE (dest) == MEM
-			   && GET_CODE (XEXP (dest, 0)) == POST_INC
-			   && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
-		      break;
-		    pushes++;
-		    if (total_pushed + GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)))
-			> stack_adjust_amount)
-		      break;
-		    total_pushed += GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
-		  }
-
-		/* Discard the amount pushed from the stack adjust;
-		   maybe eliminate it entirely.  */
-		if (total_pushed >= stack_adjust_amount)
-		  {
-		    delete_computation (stack_adjust_insn);
-		    total_pushed = stack_adjust_amount;
-		  }
-		else
-		  XEXP (SET_SRC (PATTERN (stack_adjust_insn)), 1)
-		    = GEN_INT (stack_adjust_amount - total_pushed);
-
-		/* Change the appropriate push insns to ordinary stores.  */
-		p = insn;
-		while (total_pushed > 0)
-		  {
-		    rtx pbody, dest;
-		    p = next_nonnote_insn (p);
-		    if (GET_CODE (p) != INSN)
-		      break;
-		    pbody = PATTERN (p);
-		    if (GET_CODE (pbody) != SET)
-		      break;
-		    dest = SET_DEST (pbody);
-		    /* Allow a no-op move between the adjust and the push.  */
-		    if (GET_CODE (dest) == REG
-			&& GET_CODE (SET_SRC (pbody)) == REG
-			&& REGNO (dest) == REGNO (SET_SRC (pbody)))
-		      continue;
-		    if (! (GET_CODE (dest) == MEM
-			   && GET_CODE (XEXP (dest, 0)) == POST_INC
-			   && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
-		      break;
-		    total_pushed -= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
-		    /* If this push doesn't fully fit in the space
-		       of the stack adjust that we deleted,
-		       make another stack adjust here for what we
-		       didn't use up.  There should be peepholes
-		       to recognize the resulting sequence of insns.  */
-		    if (total_pushed < 0)
-		      {
-			emit_insn_before (gen_add2_insn (stack_pointer_rtx,
-							 GEN_INT (- total_pushed)),
-					  p);
-			break;
-		      }
-		    XEXP (dest, 0)
-		      = plus_constant (stack_pointer_rtx, total_pushed);
-		  }
-	      }
-#endif
-
-	    /* Detect and delete no-op move instructions
-	       resulting from not allocating a parameter in a register.  */
-
-	    if (GET_CODE (body) == SET
-		&& (SET_DEST (body) == SET_SRC (body)
-		    || (GET_CODE (SET_DEST (body)) == MEM
-			&& GET_CODE (SET_SRC (body)) == MEM
-			&& rtx_equal_p (SET_SRC (body), SET_DEST (body))))
-		&& ! (GET_CODE (SET_DEST (body)) == MEM
-		      && MEM_VOLATILE_P (SET_DEST (body)))
-		&& ! (GET_CODE (SET_SRC (body)) == MEM
-		      && MEM_VOLATILE_P (SET_SRC (body))))
-	      delete_computation (insn);
-
-	    /* Detect and ignore no-op move instructions
-	       resulting from smart or fortuitous register allocation.  */
-
-	    else if (GET_CODE (body) == SET)
-	      {
-		int sreg = true_regnum (SET_SRC (body));
-		int dreg = true_regnum (SET_DEST (body));
-
-		if (sreg == dreg && sreg >= 0)
-		  delete_insn (insn);
-		else if (sreg >= 0 && dreg >= 0)
-		  {
-		    rtx trial;
-		    rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
-					      sreg, NULL_PTR, dreg,
-					      GET_MODE (SET_SRC (body)));
-
-		    if (tem != 0
-			&& GET_MODE (tem) == GET_MODE (SET_DEST (body)))
-		      {
-			/* DREG may have been the target of a REG_DEAD note in
-			   the insn which makes INSN redundant.  If so, reorg
-			   would still think it is dead.  So search for such a
-			   note and delete it if we find it.  */
-			if (! find_regno_note (insn, REG_UNUSED, dreg))
-			  for (trial = prev_nonnote_insn (insn);
-			       trial && GET_CODE (trial) != CODE_LABEL;
-			       trial = prev_nonnote_insn (trial))
-			    if (find_regno_note (trial, REG_DEAD, dreg))
-			      {
-				remove_death (dreg, trial);
-				break;
-			      }
-
-			/* Deleting insn could lose a death-note for SREG.  */
-			if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
-			  {
-			    /* Change this into a USE so that we won't emit
-			       code for it, but still can keep the note.  */
-			    PATTERN (insn)
-			      = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
-			    INSN_CODE (insn) = -1;
-			    /* Remove all reg notes but the REG_DEAD one.  */
-			    REG_NOTES (insn) = trial;
-			    XEXP (trial, 1) = NULL_RTX;
-			  }
-			else
-			  delete_insn (insn);
-		      }
-		  }
-		else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
-			 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
-					    NULL_PTR, 0,
-					    GET_MODE (SET_DEST (body))))
-		  {
-		    /* This handles the case where we have two consecutive
-		       assignments of the same constant to pseudos that didn't
-		       get a hard reg.  Each SET from the constant will be
-		       converted into a SET of the spill register and an
-		       output reload will be made following it.  This produces
-		       two loads of the same constant into the same spill
-		       register.  */
-
-		    rtx in_insn = insn;
-
-		    /* Look back for a death note for the first reg.
-		       If there is one, it is no longer accurate.  */
-		    while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
-		      {
-			if ((GET_CODE (in_insn) == INSN
-			     || GET_CODE (in_insn) == JUMP_INSN)
-			    && find_regno_note (in_insn, REG_DEAD, dreg))
-			  {
-			    remove_death (dreg, in_insn);
-			    break;
-			  }
-			in_insn = PREV_INSN (in_insn);
-		      }
-
-		    /* Delete the second load of the value.  */
-		    delete_insn (insn);
-		  }
-	      }
-	    else if (GET_CODE (body) == PARALLEL)
-	      {
-		/* If each part is a set between two identical registers or
-		   a USE or CLOBBER, delete the insn.  */
-		int i, sreg, dreg;
-		rtx tem;
-
-		for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
-		  {
-		    tem = XVECEXP (body, 0, i);
-		    if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
-		      continue;
-
-		    if (GET_CODE (tem) != SET
-		    	|| (sreg = true_regnum (SET_SRC (tem))) < 0
-		    	|| (dreg = true_regnum (SET_DEST (tem))) < 0
-		    	|| dreg != sreg)
-		      break;
-		  }
-		  
-		if (i < 0)
-		  delete_insn (insn);
-	      }
-	    /* Also delete insns to store bit fields if they are no-ops.  */
-	    /* Not worth the hair to detect this in the big-endian case.  */
-	    else if (! BYTES_BIG_ENDIAN
-		     && GET_CODE (body) == SET
-		     && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
-		     && XEXP (SET_DEST (body), 2) == const0_rtx
-		     && XEXP (SET_DEST (body), 0) == SET_SRC (body)
-		     && ! (GET_CODE (SET_SRC (body)) == MEM
-			   && MEM_VOLATILE_P (SET_SRC (body))))
-	      delete_insn (insn);
-	  }
-      insn = next;
-    }
+    delete_noop_moves (f);
 
   /* If we haven't yet gotten to reload and we have just run regscan,
      delete any insn that sets a register that isn't used elsewhere.
@@ -2371,41 +2032,450 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
     }
 #endif
 
-  /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
-     If so, delete it, and record that this function can drop off the end.  */
+  can_reach_end = calculate_can_reach_end (last_insn, 0, 1);
+
+  /* Show JUMP_CHAIN no longer valid.  */
+  jump_chain = 0;
+}
+
+/* Initialize LABEL_NUSES and JUMP_LABEL fields.  Delete any REG_LABEL
+   notes whose labels don't occur in the insn any more.  Returns the
+   largest INSN_UID found.  */
+static int
+init_label_info (f)
+     rtx f;
+{
+  int largest_uid = 0;
+  rtx insn;
+
+  for (insn = f; insn; insn = NEXT_INSN (insn))
+    {
+      if (GET_CODE (insn) == CODE_LABEL)
+	LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
+      else if (GET_CODE (insn) == JUMP_INSN)
+	JUMP_LABEL (insn) = 0;
+      else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
+	{
+	  rtx note, next;
+
+	  for (note = REG_NOTES (insn); note; note = next)
+	    {
+	      next = XEXP (note, 1);
+	      if (REG_NOTE_KIND (note) == REG_LABEL
+		  && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
+		remove_note (insn, note);
+	    }
+	}
+      if (INSN_UID (insn) > largest_uid)
+	largest_uid = INSN_UID (insn);
+    }
+
+  return largest_uid;
+}
+
+/* Delete insns following barriers, up to next label.  */
+static void
+delete_barrier_successors (f)
+     rtx f;
+{
+  rtx insn;
+
+  for (insn = f; insn;)
+    {
+      if (GET_CODE (insn) == BARRIER)
+	{
+	  insn = NEXT_INSN (insn);
+	  while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
+	    {
+	      if (GET_CODE (insn) == NOTE
+		  && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
+		insn = NEXT_INSN (insn);
+	      else
+		insn = delete_insn (insn);
+	    }
+	  /* INSN is now the code_label.  */
+	}
+      else
+	insn = NEXT_INSN (insn);
+    }
+}
+
+/* Mark the label each jump jumps to.
+   Combine consecutive labels, and count uses of labels.
+
+   For each label, make a chain (using `jump_chain')
+   of all the *unconditional* jumps that jump to it;
+   also make a chain of all returns.
+
+   CROSS_JUMP indicates whether we are doing cross jumping
+   and if we are whether we will be paying attention to
+   death notes or not.  */
+
+static void
+mark_all_labels (f, cross_jump)
+     rtx f;
+     int cross_jump;
+{
+  rtx insn;
+
+  for (insn = f; insn; insn = NEXT_INSN (insn))
+    if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
+      {
+	mark_jump_label (PATTERN (insn), insn, cross_jump);
+	if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
+	  {
+	    if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
+	      {
+		jump_chain[INSN_UID (insn)]
+		  = jump_chain[INSN_UID (JUMP_LABEL (insn))];
+		jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
+	      }
+	    if (GET_CODE (PATTERN (insn)) == RETURN)
+	      {
+		jump_chain[INSN_UID (insn)] = jump_chain[0];
+		jump_chain[0] = insn;
+	      }
+	  }
+      }
+}
+
+/* Delete all labels already not referenced.
+   Also find and return the last insn.  */
+
+static rtx
+delete_unreferenced_labels (f)
+     rtx f;
+{
+  rtx final = NULL_RTX;
+  rtx insn;
+
+  for (insn = f; insn; )
+    {
+      if (GET_CODE (insn) == CODE_LABEL && LABEL_NUSES (insn) == 0)
+	insn = delete_insn (insn);
+      else
+	{
+	  final = insn;
+	  insn = NEXT_INSN (insn);
+	}
+    }
+
+  return final;
+}
+
+/* Delete various simple forms of moves which have no necessary
+   side effect.  */
+
+static void
+delete_noop_moves (f)
+     rtx f;
+{
+  rtx insn, next;
+
+  for (insn = f; insn; )
+    {
+      next = NEXT_INSN (insn);
+
+      if (GET_CODE (insn) == INSN)
+	{
+	  register rtx body = PATTERN (insn);
+
+/* Combine stack_adjusts with following push_insns.  */
+#ifdef PUSH_ROUNDING
+	  if (GET_CODE (body) == SET
+	      && SET_DEST (body) == stack_pointer_rtx
+	      && GET_CODE (SET_SRC (body)) == PLUS
+	      && XEXP (SET_SRC (body), 0) == stack_pointer_rtx
+	      && GET_CODE (XEXP (SET_SRC (body), 1)) == CONST_INT
+	      && INTVAL (XEXP (SET_SRC (body), 1)) > 0)
+	    {
+	      rtx p;
+	      rtx stack_adjust_insn = insn;
+	      int stack_adjust_amount = INTVAL (XEXP (SET_SRC (body), 1));
+	      int total_pushed = 0;
+	      int pushes = 0;
+
+	      /* Find all successive push insns.  */
+	      p = insn;
+	      /* Don't convert more than three pushes;
+		 that starts adding too many displaced addresses
+		 and the whole thing starts becoming a losing
+		 proposition.  */
+	      while (pushes < 3)
+		{
+		  rtx pbody, dest;
+		  p = next_nonnote_insn (p);
+		  if (p == 0 || GET_CODE (p) != INSN)
+		    break;
+		  pbody = PATTERN (p);
+		  if (GET_CODE (pbody) != SET)
+		    break;
+		  dest = SET_DEST (pbody);
+		  /* Allow a no-op move between the adjust and the push.  */
+		  if (GET_CODE (dest) == REG
+		      && GET_CODE (SET_SRC (pbody)) == REG
+		      && REGNO (dest) == REGNO (SET_SRC (pbody)))
+		    continue;
+		  if (! (GET_CODE (dest) == MEM
+			 && GET_CODE (XEXP (dest, 0)) == POST_INC
+			 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
+		    break;
+		  pushes++;
+		  if (total_pushed + GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)))
+		      > stack_adjust_amount)
+		    break;
+		  total_pushed += GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
+		}
+
+	      /* Discard the amount pushed from the stack adjust;
+		 maybe eliminate it entirely.  */
+	      if (total_pushed >= stack_adjust_amount)
+		{
+		  delete_computation (stack_adjust_insn);
+		  total_pushed = stack_adjust_amount;
+		}
+	      else
+		XEXP (SET_SRC (PATTERN (stack_adjust_insn)), 1)
+		  = GEN_INT (stack_adjust_amount - total_pushed);
+
+	      /* Change the appropriate push insns to ordinary stores.  */
+	      p = insn;
+	      while (total_pushed > 0)
+		{
+		  rtx pbody, dest;
+		  p = next_nonnote_insn (p);
+		  if (GET_CODE (p) != INSN)
+		    break;
+		  pbody = PATTERN (p);
+		  if (GET_CODE (pbody) != SET)
+		    break;
+		  dest = SET_DEST (pbody);
+		  /* Allow a no-op move between the adjust and the push.  */
+		  if (GET_CODE (dest) == REG
+		      && GET_CODE (SET_SRC (pbody)) == REG
+		      && REGNO (dest) == REGNO (SET_SRC (pbody)))
+		    continue;
+		  if (! (GET_CODE (dest) == MEM
+			 && GET_CODE (XEXP (dest, 0)) == POST_INC
+			 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
+		    break;
+		  total_pushed -= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
+		  /* If this push doesn't fully fit in the space
+		     of the stack adjust that we deleted,
+		     make another stack adjust here for what we
+		     didn't use up.  There should be peepholes
+		     to recognize the resulting sequence of insns.  */
+		  if (total_pushed < 0)
+		    {
+		      emit_insn_before (gen_add2_insn (stack_pointer_rtx,
+						       GEN_INT (- total_pushed)),
+					p);
+		      break;
+		    }
+		  XEXP (dest, 0)
+		    = plus_constant (stack_pointer_rtx, total_pushed);
+		}
+	    }
+#endif
+
+	  /* Detect and delete no-op move instructions
+	     resulting from not allocating a parameter in a register.  */
+
+	  if (GET_CODE (body) == SET
+	      && (SET_DEST (body) == SET_SRC (body)
+		  || (GET_CODE (SET_DEST (body)) == MEM
+		      && GET_CODE (SET_SRC (body)) == MEM
+		      && rtx_equal_p (SET_SRC (body), SET_DEST (body))))
+	      && ! (GET_CODE (SET_DEST (body)) == MEM
+		    && MEM_VOLATILE_P (SET_DEST (body)))
+	      && ! (GET_CODE (SET_SRC (body)) == MEM
+		    && MEM_VOLATILE_P (SET_SRC (body))))
+	    delete_computation (insn);
+
+	  /* Detect and ignore no-op move instructions
+	     resulting from smart or fortuitous register allocation.  */
+
+	  else if (GET_CODE (body) == SET)
+	    {
+	      int sreg = true_regnum (SET_SRC (body));
+	      int dreg = true_regnum (SET_DEST (body));
+
+	      if (sreg == dreg && sreg >= 0)
+		delete_insn (insn);
+	      else if (sreg >= 0 && dreg >= 0)
+		{
+		  rtx trial;
+		  rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
+					    sreg, NULL_PTR, dreg,
+					    GET_MODE (SET_SRC (body)));
+
+		  if (tem != 0
+		      && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
+		    {
+		      /* DREG may have been the target of a REG_DEAD note in
+			 the insn which makes INSN redundant.  If so, reorg
+			 would still think it is dead.  So search for such a
+			 note and delete it if we find it.  */
+		      if (! find_regno_note (insn, REG_UNUSED, dreg))
+			for (trial = prev_nonnote_insn (insn);
+			     trial && GET_CODE (trial) != CODE_LABEL;
+			     trial = prev_nonnote_insn (trial))
+			  if (find_regno_note (trial, REG_DEAD, dreg))
+			    {
+			      remove_death (dreg, trial);
+			      break;
+			    }
+
+		      /* Deleting insn could lose a death-note for SREG.  */
+		      if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
+			{
+			  /* Change this into a USE so that we won't emit
+			     code for it, but still can keep the note.  */
+			  PATTERN (insn)
+			    = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
+			  INSN_CODE (insn) = -1;
+			  /* Remove all reg notes but the REG_DEAD one.  */
+			  REG_NOTES (insn) = trial;
+			  XEXP (trial, 1) = NULL_RTX;
+			}
+		      else
+			delete_insn (insn);
+		    }
+		}
+	      else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
+		       && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
+					  NULL_PTR, 0,
+					  GET_MODE (SET_DEST (body))))
+		{
+		  /* This handles the case where we have two consecutive
+		     assignments of the same constant to pseudos that didn't
+		     get a hard reg.  Each SET from the constant will be
+		     converted into a SET of the spill register and an
+		     output reload will be made following it.  This produces
+		     two loads of the same constant into the same spill
+		     register.  */
+
+		  rtx in_insn = insn;
+
+		  /* Look back for a death note for the first reg.
+		     If there is one, it is no longer accurate.  */
+		  while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
+		    {
+		      if ((GET_CODE (in_insn) == INSN
+			   || GET_CODE (in_insn) == JUMP_INSN)
+			  && find_regno_note (in_insn, REG_DEAD, dreg))
+			{
+			  remove_death (dreg, in_insn);
+			  break;
+			}
+		      in_insn = PREV_INSN (in_insn);
+		    }
+
+		  /* Delete the second load of the value.  */
+		  delete_insn (insn);
+		}
+	    }
+	  else if (GET_CODE (body) == PARALLEL)
+	    {
+	      /* If each part is a set between two identical registers or
+		 a USE or CLOBBER, delete the insn.  */
+	      int i, sreg, dreg;
+	      rtx tem;
+
+	      for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
+		{
+		  tem = XVECEXP (body, 0, i);
+		  if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
+		    continue;
+
+		  if (GET_CODE (tem) != SET
+		      || (sreg = true_regnum (SET_SRC (tem))) < 0
+		      || (dreg = true_regnum (SET_DEST (tem))) < 0
+		      || dreg != sreg)
+		    break;
+		}
+		  
+	      if (i < 0)
+		delete_insn (insn);
+	    }
+	  /* Also delete insns to store bit fields if they are no-ops.  */
+	  /* Not worth the hair to detect this in the big-endian case.  */
+	  else if (! BYTES_BIG_ENDIAN
+		   && GET_CODE (body) == SET
+		   && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
+		   && XEXP (SET_DEST (body), 2) == const0_rtx
+		   && XEXP (SET_DEST (body), 0) == SET_SRC (body)
+		   && ! (GET_CODE (SET_SRC (body)) == MEM
+			 && MEM_VOLATILE_P (SET_SRC (body))))
+	    delete_insn (insn);
+	}
+      insn = next;
+    }
+}
+
+/* See if there is still a NOTE_INSN_FUNCTION_END in this function.
+   If so indicate that this function can drop off the end by returning
+   1, else return 0.
+
+   CHECK_DELETED indicates whether we must check if the note being
+   searched for has the deleted flag set.
+
+   DELETE_FINAL_NOTE indicates whether we should delete the note
+   if we find it.  */
+
+static int
+calculate_can_reach_end (last, check_deleted, delete_final_note)
+     rtx last;
+     int check_deleted;
+     int delete_final_note;
+{
+  rtx insn = last;
+  int n_labels = 1;
+
+  while (insn != NULL_RTX)
+    {
+      int ok = 0;
+
+      /* One label can follow the end-note: the return label.  */
+      if (GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
+	ok = 1;
+      /* Ordinary insns can follow it if returning a structure.  */
+      else if (GET_CODE (insn) == INSN)
+	ok = 1;
+      /* If machine uses explicit RETURN insns, no epilogue,
+	 then one of them follows the note.  */
+      else if (GET_CODE (insn) == JUMP_INSN
+	       && GET_CODE (PATTERN (insn)) == RETURN)
+	ok = 1;
+      /* A barrier can follow the return insn.  */
+      else if (GET_CODE (insn) == BARRIER)
+	ok = 1;
+      /* Other kinds of notes can follow also.  */
+      else if (GET_CODE (insn) == NOTE
+	       && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
+	ok = 1;
+
+      if (ok != 1)
+	break;
 
-  insn = last_insn;
-  {
-    int n_labels = 1;
-    while (insn
-	   /* One label can follow the end-note: the return label.  */
-	   && ((GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
-	       /* Ordinary insns can follow it if returning a structure.  */
-	       || GET_CODE (insn) == INSN
-	       /* If machine uses explicit RETURN insns, no epilogue,
-		  then one of them follows the note.  */
-	       || (GET_CODE (insn) == JUMP_INSN
-		   && GET_CODE (PATTERN (insn)) == RETURN)
-	       /* A barrier can follow the return insn.  */
-	       || GET_CODE (insn) == BARRIER
-	       /* Other kinds of notes can follow also.  */
-	       || (GET_CODE (insn) == NOTE
-		   && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)))
       insn = PREV_INSN (insn);
-  }
+    }
 
-  /* Report if control can fall through at the end of the function.  */
-  if (insn && GET_CODE (insn) == NOTE
-      && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END)
+  /* See if we backed up to the appropriate type of note.  */
+  if (insn != NULL_RTX
+      && GET_CODE (insn) == NOTE
+      && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END
+      && (check_deleted != 0
+	  && ! INSN_DELETED_P (insn)))
     {
-      can_reach_end = 1;
-      delete_insn (insn);
+      if (delete_final_note)
+	delete_insn (insn);
+      return 1;
     }
 
-  /* Show JUMP_CHAIN no longer valid.  */
-  jump_chain = 0;
+  return 0;
 }
-
+
 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
    jump.  Assume that this unconditional jump is to the exit test code.  If
    the code is sufficiently simple, make a copy of it before INSN,