Initial checkin of GCC 4.9.0 from trunk (r208799).

Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba

1 files changed, 1756 insertions, 0 deletions

diff --git a/gcc-4.9/gcc/ipa-split.c b/gcc-4.9/gcc/ipa-split.c
new file mode 100644
index 000000000..38bd88365
--- /dev/null
+++ b/gcc-4.9/gcc/ipa-split.c
@@ -0,0 +1,1756 @@
+/* Function splitting pass
+   Copyright (C) 2010-2014 Free Software Foundation, Inc.
+   Contributed by Jan Hubicka  <jh@suse.cz>
+
+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/>.  */
+
+/* The purpose of this pass is to split function bodies to improve
+   inlining.  I.e. for function of the form:
+
+   func (...)
+     {
+       if (cheap_test)
+	 something_small
+       else
+	 something_big
+     }
+
+   Produce:
+
+   func.part (...)
+     {
+	something_big
+     }
+
+   func (...)
+     {
+       if (cheap_test)
+	 something_small
+       else
+	 func.part (...);
+     }
+
+   When func becomes inlinable and when cheap_test is often true, inlining func,
+   but not fund.part leads to performance improvement similar as inlining
+   original func while the code size growth is smaller.
+
+   The pass is organized in three stages:
+   1) Collect local info about basic block into BB_INFO structure and
+      compute function body estimated size and time.
+   2) Via DFS walk find all possible basic blocks where we can split
+      and chose best one.
+   3) If split point is found, split at the specified BB by creating a clone
+      and updating function to call it.  
+
+   The decisions what functions to split are in execute_split_functions
+   and consider_split.  
+
+   There are several possible future improvements for this pass including:
+
+   1) Splitting to break up large functions
+   2) Splitting to reduce stack frame usage
+   3) Allow split part of function to use values computed in the header part.
+      The values needs to be passed to split function, perhaps via same
+      interface as for nested functions or as argument.
+   4) Support for simple rematerialization.  I.e. when split part use
+      value computed in header from function parameter in very cheap way, we
+      can just recompute it.
+   5) Support splitting of nested functions.
+   6) Support non-SSA arguments.  
+   7) There is nothing preventing us from producing multiple parts of single function
+      when needed or splitting also the parts.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tree.h"
+#include "basic-block.h"
+#include "tree-ssa-alias.h"
+#include "internal-fn.h"
+#include "gimple-expr.h"
+#include "is-a.h"
+#include "gimple.h"
+#include "stringpool.h"
+#include "expr.h"
+#include "calls.h"
+#include "gimplify.h"
+#include "gimple-iterator.h"
+#include "gimplify-me.h"
+#include "gimple-walk.h"
+#include "target.h"
+#include "ipa-prop.h"
+#include "gimple-ssa.h"
+#include "tree-cfg.h"
+#include "tree-phinodes.h"
+#include "ssa-iterators.h"
+#include "stringpool.h"
+#include "tree-ssanames.h"
+#include "tree-into-ssa.h"
+#include "tree-dfa.h"
+#include "tree-pass.h"
+#include "flags.h"
+#include "diagnostic.h"
+#include "tree-dump.h"
+#include "tree-inline.h"
+#include "params.h"
+#include "gimple-pretty-print.h"
+#include "ipa-inline.h"
+#include "cfgloop.h"
+
+/* Per basic block info.  */
+
+typedef struct
+{
+  unsigned int size;
+  unsigned int time;
+} bb_info;
+
+static vec<bb_info> bb_info_vec;
+
+/* Description of split point.  */
+
+struct split_point
+{
+  /* Size of the partitions.  */
+  unsigned int header_time, header_size, split_time, split_size;
+
+  /* SSA names that need to be passed into spit function.  */
+  bitmap ssa_names_to_pass;
+
+  /* Basic block where we split (that will become entry point of new function.  */
+  basic_block entry_bb;
+
+  /* Basic blocks we are splitting away.  */
+  bitmap split_bbs;
+
+  /* True when return value is computed on split part and thus it needs
+     to be returned.  */
+  bool split_part_set_retval;
+};
+
+/* Best split point found.  */
+
+struct split_point best_split_point;
+
+/* Set of basic blocks that are not allowed to dominate a split point.  */
+
+static bitmap forbidden_dominators;
+
+static tree find_retval (basic_block return_bb);
+
+/* Callback for walk_stmt_load_store_addr_ops.  If T is non-SSA automatic
+   variable, check it if it is present in bitmap passed via DATA.  */
+
+static bool
+test_nonssa_use (gimple, tree t, tree, void *data)
+{
+  t = get_base_address (t);
+
+  if (!t || is_gimple_reg (t))
+    return false;
+
+  if (TREE_CODE (t) == PARM_DECL
+      || (TREE_CODE (t) == VAR_DECL
+	  && auto_var_in_fn_p (t, current_function_decl))
+      || TREE_CODE (t) == RESULT_DECL
+      || TREE_CODE (t) == LABEL_DECL)
+    return bitmap_bit_p ((bitmap)data, DECL_UID (t));
+
+  /* For DECL_BY_REFERENCE, the return value is actually a pointer.  We want
+     to pretend that the value pointed to is actual result decl.  */
+  if ((TREE_CODE (t) == MEM_REF || INDIRECT_REF_P (t))
+      && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
+      && SSA_NAME_VAR (TREE_OPERAND (t, 0))
+      && TREE_CODE (SSA_NAME_VAR (TREE_OPERAND (t, 0))) == RESULT_DECL
+      && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl)))
+    return
+      bitmap_bit_p ((bitmap)data,
+		    DECL_UID (DECL_RESULT (current_function_decl)));
+
+  return false;
+}
+
+/* Dump split point CURRENT.  */
+
+static void
+dump_split_point (FILE * file, struct split_point *current)
+{
+  fprintf (file,
+	   "Split point at BB %i\n"
+	   "  header time: %i header size: %i\n"
+	   "  split time: %i split size: %i\n  bbs: ",
+	   current->entry_bb->index, current->header_time,
+	   current->header_size, current->split_time, current->split_size);
+  dump_bitmap (file, current->split_bbs);
+  fprintf (file, "  SSA names to pass: ");
+  dump_bitmap (file, current->ssa_names_to_pass);
+}
+
+/* Look for all BBs in header that might lead to the split part and verify
+   that they are not defining any non-SSA var used by the split part.
+   Parameters are the same as for consider_split.  */
+
+static bool
+verify_non_ssa_vars (struct split_point *current, bitmap non_ssa_vars,
+		     basic_block return_bb)
+{
+  bitmap seen = BITMAP_ALLOC (NULL);
+  vec<basic_block> worklist = vNULL;
+  edge e;
+  edge_iterator ei;
+  bool ok = true;
+
+  FOR_EACH_EDGE (e, ei, current->entry_bb->preds)
+    if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun)
+	&& !bitmap_bit_p (current->split_bbs, e->src->index))
+      {
+        worklist.safe_push (e->src);
+	bitmap_set_bit (seen, e->src->index);
+      }
+
+  while (!worklist.is_empty ())
+    {
+      gimple_stmt_iterator bsi;
+      basic_block bb = worklist.pop ();
+
+      FOR_EACH_EDGE (e, ei, bb->preds)
+	if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun)
+	    && bitmap_set_bit (seen, e->src->index))
+	  {
+	    gcc_checking_assert (!bitmap_bit_p (current->split_bbs,
+					        e->src->index));
+	    worklist.safe_push (e->src);
+	  }
+      for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
+	{
+	  gimple stmt = gsi_stmt (bsi);
+	  if (is_gimple_debug (stmt))
+	    continue;
+	  if (walk_stmt_load_store_addr_ops
+	      (stmt, non_ssa_vars, test_nonssa_use, test_nonssa_use,
+	       test_nonssa_use))
+	    {
+	      ok = false;
+	      goto done;
+	    }
+	  if (gimple_code (stmt) == GIMPLE_LABEL
+	      && test_nonssa_use (stmt, gimple_label_label (stmt),
+				  NULL_TREE, non_ssa_vars))
+	  {
+	    ok = false;
+	    goto done;
+	  }
+	}
+      for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
+	{
+	  if (walk_stmt_load_store_addr_ops
+	      (gsi_stmt (bsi), non_ssa_vars, test_nonssa_use, test_nonssa_use,
+	       test_nonssa_use))
+	    {
+	      ok = false;
+	      goto done;
+	    }
+	}
+      FOR_EACH_EDGE (e, ei, bb->succs)
+	{
+	  if (e->dest != return_bb)
+	    continue;
+	  for (bsi = gsi_start_phis (return_bb); !gsi_end_p (bsi);
+	       gsi_next (&bsi))
+	    {
+	      gimple stmt = gsi_stmt (bsi);
+	      tree op = gimple_phi_arg_def (stmt, e->dest_idx);
+
+	      if (virtual_operand_p (gimple_phi_result (stmt)))
+		continue;
+	      if (TREE_CODE (op) != SSA_NAME
+		  && test_nonssa_use (stmt, op, op, non_ssa_vars))
+		{
+		  ok = false;
+		  goto done;
+		}
+	    }
+	}
+    }
+done:
+  BITMAP_FREE (seen);
+  worklist.release ();
+  return ok;
+}
+
+/* If STMT is a call, check the callee against a list of forbidden
+   predicate functions.  If a match is found, look for uses of the
+   call result in condition statements that compare against zero.
+   For each such use, find the block targeted by the condition
+   statement for the nonzero result, and set the bit for this block
+   in the forbidden dominators bitmap.  The purpose of this is to avoid
+   selecting a split point where we are likely to lose the chance
+   to optimize away an unused function call.  */
+
+static void
+check_forbidden_calls (gimple stmt)
+{
+  imm_use_iterator use_iter;
+  use_operand_p use_p;
+  tree lhs;
+
+  /* At the moment, __builtin_constant_p is the only forbidden
+     predicate function call (see PR49642).  */
+  if (!gimple_call_builtin_p (stmt, BUILT_IN_CONSTANT_P))
+    return;
+
+  lhs = gimple_call_lhs (stmt);
+
+  if (!lhs || TREE_CODE (lhs) != SSA_NAME)
+    return;
+
+  FOR_EACH_IMM_USE_FAST (use_p, use_iter, lhs)
+    {
+      tree op1;
+      basic_block use_bb, forbidden_bb;
+      enum tree_code code;
+      edge true_edge, false_edge;
+      gimple use_stmt = USE_STMT (use_p);
+
+      if (gimple_code (use_stmt) != GIMPLE_COND)
+	continue;
+
+      /* Assuming canonical form for GIMPLE_COND here, with constant
+	 in second position.  */
+      op1 = gimple_cond_rhs (use_stmt);
+      code = gimple_cond_code (use_stmt);
+      use_bb = gimple_bb (use_stmt);
+
+      extract_true_false_edges_from_block (use_bb, &true_edge, &false_edge);
+
+      /* We're only interested in comparisons that distinguish
+	 unambiguously from zero.  */
+      if (!integer_zerop (op1) || code == LE_EXPR || code == GE_EXPR)
+	continue;
+
+      if (code == EQ_EXPR)
+	forbidden_bb = false_edge->dest;
+      else
+	forbidden_bb = true_edge->dest;
+
+      bitmap_set_bit (forbidden_dominators, forbidden_bb->index);
+    }
+}
+
+/* If BB is dominated by any block in the forbidden dominators set,
+   return TRUE; else FALSE.  */
+
+static bool
+dominated_by_forbidden (basic_block bb)
+{
+  unsigned dom_bb;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (forbidden_dominators, 1, dom_bb, bi)
+    {
+      if (dominated_by_p (CDI_DOMINATORS, bb,
+			  BASIC_BLOCK_FOR_FN (cfun, dom_bb)))
+	return true;
+    }
+
+  return false;
+}
+
+/* We found an split_point CURRENT.  NON_SSA_VARS is bitmap of all non ssa
+   variables used and RETURN_BB is return basic block.
+   See if we can split function here.  */
+
+static void
+consider_split (struct split_point *current, bitmap non_ssa_vars,
+		basic_block return_bb)
+{
+  tree parm;
+  unsigned int num_args = 0;
+  unsigned int call_overhead;
+  edge e;
+  edge_iterator ei;
+  gimple_stmt_iterator bsi;
+  unsigned int i;
+  int incoming_freq = 0;
+  tree retval;
+  bool back_edge = false;
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    dump_split_point (dump_file, current);
+
+  FOR_EACH_EDGE (e, ei, current->entry_bb->preds)
+    {
+      if (e->flags & EDGE_DFS_BACK)
+	back_edge = true;
+      if (!bitmap_bit_p (current->split_bbs, e->src->index))
+        incoming_freq += EDGE_FREQUENCY (e);
+    }
+
+  /* Do not split when we would end up calling function anyway.  */
+  if (incoming_freq
+      >= (ENTRY_BLOCK_PTR_FOR_FN (cfun)->frequency
+	  * PARAM_VALUE (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY) / 100))
+    {
+      /* When profile is guessed, we can not expect it to give us
+	 realistic estimate on likelyness of function taking the
+	 complex path.  As a special case, when tail of the function is
+	 a loop, enable splitting since inlining code skipping the loop
+	 is likely noticeable win.  */
+      if (back_edge
+	  && profile_status_for_fn (cfun) != PROFILE_READ
+	  && incoming_freq < ENTRY_BLOCK_PTR_FOR_FN (cfun)->frequency)
+	{
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    fprintf (dump_file,
+		     "  Split before loop, accepting despite low frequencies %i %i.\n",
+		     incoming_freq,
+		     ENTRY_BLOCK_PTR_FOR_FN (cfun)->frequency);
+	}
+      else
+	{
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    fprintf (dump_file,
+		     "  Refused: incoming frequency is too large.\n");
+	  return;
+	}
+    }
+
+  if (!current->header_size)
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, "  Refused: header empty\n");
+      return;
+    }
+
+  /* Verify that PHI args on entry are either virtual or all their operands
+     incoming from header are the same.  */
+  for (bsi = gsi_start_phis (current->entry_bb); !gsi_end_p (bsi); gsi_next (&bsi))
+    {
+      gimple stmt = gsi_stmt (bsi);
+      tree val = NULL;
+
+      if (virtual_operand_p (gimple_phi_result (stmt)))
+	continue;
+      for (i = 0; i < gimple_phi_num_args (stmt); i++)
+	{
+	  edge e = gimple_phi_arg_edge (stmt, i);
+	  if (!bitmap_bit_p (current->split_bbs, e->src->index))
+	    {
+	      tree edge_val = gimple_phi_arg_def (stmt, i);
+	      if (val && edge_val != val)
+	        {
+		  if (dump_file && (dump_flags & TDF_DETAILS))
+		    fprintf (dump_file,
+			     "  Refused: entry BB has PHI with multiple variants\n");
+		  return;
+	        }
+	      val = edge_val;
+	    }
+	}
+    }
+
+
+  /* See what argument we will pass to the split function and compute
+     call overhead.  */
+  call_overhead = eni_size_weights.call_cost;
+  for (parm = DECL_ARGUMENTS (current_function_decl); parm;
+       parm = DECL_CHAIN (parm))
+    {
+      if (!is_gimple_reg (parm))
+	{
+	  if (bitmap_bit_p (non_ssa_vars, DECL_UID (parm)))
+	    {
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		fprintf (dump_file,
+			 "  Refused: need to pass non-ssa param values\n");
+	      return;
+	    }
+	}
+      else
+	{
+	  tree ddef = ssa_default_def (cfun, parm);
+	  if (ddef
+	      && bitmap_bit_p (current->ssa_names_to_pass,
+			       SSA_NAME_VERSION (ddef)))
+	    {
+	      if (!VOID_TYPE_P (TREE_TYPE (parm)))
+		call_overhead += estimate_move_cost (TREE_TYPE (parm));
+	      num_args++;
+	    }
+	}
+    }
+  if (!VOID_TYPE_P (TREE_TYPE (current_function_decl)))
+    call_overhead += estimate_move_cost (TREE_TYPE (current_function_decl));
+
+  if (current->split_size <= call_overhead)
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file,
+		 "  Refused: split size is smaller than call overhead\n");
+      return;
+    }
+  if (current->header_size + call_overhead
+      >= (unsigned int)(DECL_DECLARED_INLINE_P (current_function_decl)
+			? MAX_INLINE_INSNS_SINGLE
+			: MAX_INLINE_INSNS_AUTO))
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file,
+		 "  Refused: header size is too large for inline candidate\n");
+      return;
+    }
+
+  /* FIXME: we currently can pass only SSA function parameters to the split
+     arguments.  Once parm_adjustment infrastructure is supported by cloning,
+     we can pass more than that.  */
+  if (num_args != bitmap_count_bits (current->ssa_names_to_pass))
+    {
+      
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file,
+		 "  Refused: need to pass non-param values\n");
+      return;
+    }
+
+  /* When there are non-ssa vars used in the split region, see if they
+     are used in the header region.  If so, reject the split.
+     FIXME: we can use nested function support to access both.  */
+  if (!bitmap_empty_p (non_ssa_vars)
+      && !verify_non_ssa_vars (current, non_ssa_vars, return_bb))
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file,
+		 "  Refused: split part has non-ssa uses\n");
+      return;
+    }
+
+  /* If the split point is dominated by a forbidden block, reject
+     the split.  */
+  if (!bitmap_empty_p (forbidden_dominators)
+      && dominated_by_forbidden (current->entry_bb))
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file,
+		 "  Refused: split point dominated by forbidden block\n");
+      return;
+    }
+
+  /* See if retval used by return bb is computed by header or split part.
+     When it is computed by split part, we need to produce return statement
+     in the split part and add code to header to pass it around.
+
+     This is bit tricky to test:
+       1) When there is no return_bb or no return value, we always pass
+          value around.
+       2) Invariants are always computed by caller.
+       3) For SSA we need to look if defining statement is in header or split part
+       4) For non-SSA we need to look where the var is computed. */
+  retval = find_retval (return_bb);
+  if (!retval)
+    current->split_part_set_retval = true;
+  else if (is_gimple_min_invariant (retval))
+    current->split_part_set_retval = false;
+  /* Special case is value returned by reference we record as if it was non-ssa
+     set to result_decl.  */
+  else if (TREE_CODE (retval) == SSA_NAME
+	   && SSA_NAME_VAR (retval)
+	   && TREE_CODE (SSA_NAME_VAR (retval)) == RESULT_DECL
+	   && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl)))
+    current->split_part_set_retval
+       = bitmap_bit_p (non_ssa_vars, DECL_UID (SSA_NAME_VAR (retval)));
+  else if (TREE_CODE (retval) == SSA_NAME)
+    current->split_part_set_retval
+      = (!SSA_NAME_IS_DEFAULT_DEF (retval)
+	 && (bitmap_bit_p (current->split_bbs,
+			  gimple_bb (SSA_NAME_DEF_STMT (retval))->index)
+	     || gimple_bb (SSA_NAME_DEF_STMT (retval)) == return_bb));
+  else if (TREE_CODE (retval) == PARM_DECL)
+    current->split_part_set_retval = false;
+  else if (TREE_CODE (retval) == VAR_DECL
+	   || TREE_CODE (retval) == RESULT_DECL)
+    current->split_part_set_retval
+      = bitmap_bit_p (non_ssa_vars, DECL_UID (retval));
+  else
+    current->split_part_set_retval = true;
+
+  /* split_function fixes up at most one PHI non-virtual PHI node in return_bb,
+     for the return value.  If there are other PHIs, give up.  */
+  if (return_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
+    {
+      gimple_stmt_iterator psi;
+
+      for (psi = gsi_start_phis (return_bb); !gsi_end_p (psi); gsi_next (&psi))
+	if (!virtual_operand_p (gimple_phi_result (gsi_stmt (psi)))
+	    && !(retval
+		 && current->split_part_set_retval
+		 && TREE_CODE (retval) == SSA_NAME
+		 && !DECL_BY_REFERENCE (DECL_RESULT (current_function_decl))
+		 && SSA_NAME_DEF_STMT (retval) == gsi_stmt (psi)))
+	  {
+	    if (dump_file && (dump_flags & TDF_DETAILS))
+	      fprintf (dump_file,
+		       "  Refused: return bb has extra PHIs\n");
+	    return;
+	  }
+    }
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    fprintf (dump_file, "  Accepted!\n");
+
+  /* At the moment chose split point with lowest frequency and that leaves
+     out smallest size of header.
+     In future we might re-consider this heuristics.  */
+  if (!best_split_point.split_bbs
+      || best_split_point.entry_bb->frequency > current->entry_bb->frequency
+      || (best_split_point.entry_bb->frequency == current->entry_bb->frequency
+	  && best_split_point.split_size < current->split_size))
+	
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, "  New best split point!\n");
+      if (best_split_point.ssa_names_to_pass)
+	{
+	  BITMAP_FREE (best_split_point.ssa_names_to_pass);
+	  BITMAP_FREE (best_split_point.split_bbs);
+	}
+      best_split_point = *current;
+      best_split_point.ssa_names_to_pass = BITMAP_ALLOC (NULL);
+      bitmap_copy (best_split_point.ssa_names_to_pass,
+		   current->ssa_names_to_pass);
+      best_split_point.split_bbs = BITMAP_ALLOC (NULL);
+      bitmap_copy (best_split_point.split_bbs, current->split_bbs);
+    }
+}
+
+/* Return basic block containing RETURN statement.  We allow basic blocks
+   of the form:
+   <retval> = tmp_var;
+   return <retval>
+   but return_bb can not be more complex than this.
+   If nothing is found, return the exit block.
+
+   When there are multiple RETURN statement, chose one with return value,
+   since that one is more likely shared by multiple code paths.
+
+   Return BB is special, because for function splitting it is the only
+   basic block that is duplicated in between header and split part of the
+   function.
+
+   TODO: We might support multiple return blocks.  */
+
+static basic_block
+find_return_bb (void)
+{
+  edge e;
+  basic_block return_bb = EXIT_BLOCK_PTR_FOR_FN (cfun);
+  gimple_stmt_iterator bsi;
+  bool found_return = false;
+  tree retval = NULL_TREE;
+
+  if (!single_pred_p (EXIT_BLOCK_PTR_FOR_FN (cfun)))
+    return return_bb;
+
+  e = single_pred_edge (EXIT_BLOCK_PTR_FOR_FN (cfun));
+  for (bsi = gsi_last_bb (e->src); !gsi_end_p (bsi); gsi_prev (&bsi))
+    {
+      gimple stmt = gsi_stmt (bsi);
+      if (gimple_code (stmt) == GIMPLE_LABEL
+	  || is_gimple_debug (stmt)
+	  || gimple_clobber_p (stmt))
+	;
+      else if (gimple_code (stmt) == GIMPLE_ASSIGN
+	       && found_return
+	       && gimple_assign_single_p (stmt)
+	       && (auto_var_in_fn_p (gimple_assign_rhs1 (stmt),
+				     current_function_decl)
+		   || is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
+	       && retval == gimple_assign_lhs (stmt))
+	;
+      else if (gimple_code (stmt) == GIMPLE_RETURN)
+	{
+	  found_return = true;
+	  retval = gimple_return_retval (stmt);
+	}
+      else
+	break;
+    }
+  if (gsi_end_p (bsi) && found_return)
+    return_bb = e->src;
+
+  return return_bb;
+}
+
+/* Given return basic block RETURN_BB, see where return value is really
+   stored.  */
+static tree
+find_retval (basic_block return_bb)
+{
+  gimple_stmt_iterator bsi;
+  for (bsi = gsi_start_bb (return_bb); !gsi_end_p (bsi); gsi_next (&bsi))
+    if (gimple_code (gsi_stmt (bsi)) == GIMPLE_RETURN)
+      return gimple_return_retval (gsi_stmt (bsi));
+    else if (gimple_code (gsi_stmt (bsi)) == GIMPLE_ASSIGN
+	     && !gimple_clobber_p (gsi_stmt (bsi)))
+      return gimple_assign_rhs1 (gsi_stmt (bsi));
+  return NULL;
+}
+
+/* Callback for walk_stmt_load_store_addr_ops.  If T is non-SSA automatic
+   variable, mark it as used in bitmap passed via DATA.
+   Return true when access to T prevents splitting the function.  */
+
+static bool
+mark_nonssa_use (gimple, tree t, tree, void *data)
+{
+  t = get_base_address (t);
+
+  if (!t || is_gimple_reg (t))
+    return false;
+
+  /* At present we can't pass non-SSA arguments to split function.
+     FIXME: this can be relaxed by passing references to arguments.  */
+  if (TREE_CODE (t) == PARM_DECL)
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file,
+		 "Cannot split: use of non-ssa function parameter.\n");
+      return true;
+    }
+
+  if ((TREE_CODE (t) == VAR_DECL
+       && auto_var_in_fn_p (t, current_function_decl))
+      || TREE_CODE (t) == RESULT_DECL
+      || TREE_CODE (t) == LABEL_DECL)
+    bitmap_set_bit ((bitmap)data, DECL_UID (t));
+
+  /* For DECL_BY_REFERENCE, the return value is actually a pointer.  We want
+     to pretend that the value pointed to is actual result decl.  */
+  if ((TREE_CODE (t) == MEM_REF || INDIRECT_REF_P (t))
+      && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
+      && SSA_NAME_VAR (TREE_OPERAND (t, 0))
+      && TREE_CODE (SSA_NAME_VAR (TREE_OPERAND (t, 0))) == RESULT_DECL
+      && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl)))
+    return
+      bitmap_bit_p ((bitmap)data,
+		    DECL_UID (DECL_RESULT (current_function_decl)));
+
+  return false;
+}
+
+/* Compute local properties of basic block BB we collect when looking for
+   split points.  We look for ssa defs and store them in SET_SSA_NAMES,
+   for ssa uses and store them in USED_SSA_NAMES and for any non-SSA automatic
+   vars stored in NON_SSA_VARS.
+
+   When BB has edge to RETURN_BB, collect uses in RETURN_BB too.  
+
+   Return false when BB contains something that prevents it from being put into
+   split function.  */
+
+static bool
+visit_bb (basic_block bb, basic_block return_bb,
+	  bitmap set_ssa_names, bitmap used_ssa_names,
+	  bitmap non_ssa_vars)
+{
+  gimple_stmt_iterator bsi;
+  edge e;
+  edge_iterator ei;
+  bool can_split = true;
+
+  for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
+    {
+      gimple stmt = gsi_stmt (bsi);
+      tree op;
+      ssa_op_iter iter;
+      tree decl;
+
+      if (is_gimple_debug (stmt))
+	continue;
+
+      if (gimple_clobber_p (stmt))
+	continue;
+
+      /* FIXME: We can split regions containing EH.  We can not however
+	 split RESX, EH_DISPATCH and EH_POINTER referring to same region
+	 into different partitions.  This would require tracking of
+	 EH regions and checking in consider_split_point if they 
+	 are not used elsewhere.  */
+      if (gimple_code (stmt) == GIMPLE_RESX)
+	{
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    fprintf (dump_file, "Cannot split: resx.\n");
+	  can_split = false;
+	}
+      if (gimple_code (stmt) == GIMPLE_EH_DISPATCH)
+	{
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    fprintf (dump_file, "Cannot split: eh dispatch.\n");
+	  can_split = false;
+	}
+
+      /* Check builtins that prevent splitting.  */
+      if (gimple_code (stmt) == GIMPLE_CALL
+	  && (decl = gimple_call_fndecl (stmt)) != NULL_TREE
+	  && DECL_BUILT_IN (decl)
+	  && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
+	switch (DECL_FUNCTION_CODE (decl))
+	  {
+	  /* FIXME: once we will allow passing non-parm values to split part,
+	     we need to be sure to handle correct builtin_stack_save and
+	     builtin_stack_restore.  At the moment we are safe; there is no
+	     way to store builtin_stack_save result in non-SSA variable
+	     since all calls to those are compiler generated.  */
+	  case BUILT_IN_APPLY:
+	  case BUILT_IN_APPLY_ARGS:
+	  case BUILT_IN_VA_START:
+	    if (dump_file && (dump_flags & TDF_DETAILS))
+	      fprintf (dump_file,
+		       "Cannot split: builtin_apply and va_start.\n");
+	    can_split = false;
+	    break;
+	  case BUILT_IN_EH_POINTER:
+	    if (dump_file && (dump_flags & TDF_DETAILS))
+	      fprintf (dump_file, "Cannot split: builtin_eh_pointer.\n");
+	    can_split = false;
+	    break;
+	  default:
+	    break;
+	  }
+
+      FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF)
+	bitmap_set_bit (set_ssa_names, SSA_NAME_VERSION (op));
+      FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
+	bitmap_set_bit (used_ssa_names, SSA_NAME_VERSION (op));
+      can_split &= !walk_stmt_load_store_addr_ops (stmt, non_ssa_vars,
+						   mark_nonssa_use,
+						   mark_nonssa_use,
+						   mark_nonssa_use);
+    }
+  for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
+    {
+      gimple stmt = gsi_stmt (bsi);
+      unsigned int i;
+
+      if (virtual_operand_p (gimple_phi_result (stmt)))
+	continue;
+      bitmap_set_bit (set_ssa_names,
+		      SSA_NAME_VERSION (gimple_phi_result (stmt)));
+      for (i = 0; i < gimple_phi_num_args (stmt); i++)
+	{
+	  tree op = gimple_phi_arg_def (stmt, i);
+	  if (TREE_CODE (op) == SSA_NAME)
+	    bitmap_set_bit (used_ssa_names, SSA_NAME_VERSION (op));
+	}
+      can_split &= !walk_stmt_load_store_addr_ops (stmt, non_ssa_vars,
+						   mark_nonssa_use,
+						   mark_nonssa_use,
+						   mark_nonssa_use);
+    }
+  /* Record also uses coming from PHI operand in return BB.  */
+  FOR_EACH_EDGE (e, ei, bb->succs)
+    if (e->dest == return_bb)
+      {
+	for (bsi = gsi_start_phis (return_bb); !gsi_end_p (bsi); gsi_next (&bsi))
+	  {
+	    gimple stmt = gsi_stmt (bsi);
+	    tree op = gimple_phi_arg_def (stmt, e->dest_idx);
+
+	    if (virtual_operand_p (gimple_phi_result (stmt)))
+	      continue;
+	    if (TREE_CODE (op) == SSA_NAME)
+	      bitmap_set_bit (used_ssa_names, SSA_NAME_VERSION (op));
+	    else
+	      can_split &= !mark_nonssa_use (stmt, op, op, non_ssa_vars);
+	  }
+      }
+  return can_split;
+}
+
+/* Stack entry for recursive DFS walk in find_split_point.  */
+
+typedef struct
+{
+  /* Basic block we are examining.  */
+  basic_block bb;
+
+  /* SSA names set and used by the BB and all BBs reachable
+     from it via DFS walk.  */
+  bitmap set_ssa_names, used_ssa_names;
+  bitmap non_ssa_vars;
+
+  /* All BBS visited from this BB via DFS walk.  */
+  bitmap bbs_visited;
+
+  /* Last examined edge in DFS walk.  Since we walk unoriented graph,
+     the value is up to sum of incoming and outgoing edges of BB.  */
+  unsigned int edge_num;
+
+  /* Stack entry index of earliest BB reachable from current BB
+     or any BB visited later in DFS walk.  */
+  int earliest;
+
+  /* Overall time and size of all BBs reached from this BB in DFS walk.  */
+  int overall_time, overall_size;
+
+  /* When false we can not split on this BB.  */
+  bool can_split;
+} stack_entry;
+
+
+/* Find all articulations and call consider_split on them.
+   OVERALL_TIME and OVERALL_SIZE is time and size of the function.
+
+   We perform basic algorithm for finding an articulation in a graph
+   created from CFG by considering it to be an unoriented graph.
+
+   The articulation is discovered via DFS walk. We collect earliest
+   basic block on stack that is reachable via backward edge.  Articulation
+   is any basic block such that there is no backward edge bypassing it.
+   To reduce stack usage we maintain heap allocated stack in STACK vector.
+   AUX pointer of BB is set to index it appears in the stack or -1 once
+   it is visited and popped off the stack.
+
+   The algorithm finds articulation after visiting the whole component
+   reachable by it.  This makes it convenient to collect information about
+   the component used by consider_split.  */
+
+static void
+find_split_points (int overall_time, int overall_size)
+{
+  stack_entry first;
+  vec<stack_entry> stack = vNULL;
+  basic_block bb;
+  basic_block return_bb = find_return_bb ();
+  struct split_point current;
+
+  current.header_time = overall_time;
+  current.header_size = overall_size;
+  current.split_time = 0;
+  current.split_size = 0;
+  current.ssa_names_to_pass = BITMAP_ALLOC (NULL);
+
+  first.bb = ENTRY_BLOCK_PTR_FOR_FN (cfun);
+  first.edge_num = 0;
+  first.overall_time = 0;
+  first.overall_size = 0;
+  first.earliest = INT_MAX;
+  first.set_ssa_names = 0;
+  first.used_ssa_names = 0;
+  first.non_ssa_vars = 0;
+  first.bbs_visited = 0;
+  first.can_split = false;
+  stack.safe_push (first);
+  ENTRY_BLOCK_PTR_FOR_FN (cfun)->aux = (void *)(intptr_t)-1;
+
+  while (!stack.is_empty ())
+    {
+      stack_entry *entry = &stack.last ();
+
+      /* We are walking an acyclic graph, so edge_num counts
+	 succ and pred edges together.  However when considering
+         articulation, we want to have processed everything reachable
+	 from articulation but nothing that reaches into it.  */
+      if (entry->edge_num == EDGE_COUNT (entry->bb->succs)
+	  && entry->bb != ENTRY_BLOCK_PTR_FOR_FN (cfun))
+	{
+	  int pos = stack.length ();
+	  entry->can_split &= visit_bb (entry->bb, return_bb,
+					entry->set_ssa_names,
+					entry->used_ssa_names,
+					entry->non_ssa_vars);
+	  if (pos <= entry->earliest && !entry->can_split
+	      && dump_file && (dump_flags & TDF_DETAILS))
+	    fprintf (dump_file,
+		     "found articulation at bb %i but can not split\n",
+		     entry->bb->index);
+	  if (pos <= entry->earliest && entry->can_split)
+	     {
+	       if (dump_file && (dump_flags & TDF_DETAILS))
+		 fprintf (dump_file, "found articulation at bb %i\n",
+			  entry->bb->index);
+	       current.entry_bb = entry->bb;
+	       current.ssa_names_to_pass = BITMAP_ALLOC (NULL);
+	       bitmap_and_compl (current.ssa_names_to_pass,
+				 entry->used_ssa_names, entry->set_ssa_names);
+	       current.header_time = overall_time - entry->overall_time;
+	       current.header_size = overall_size - entry->overall_size;
+	       current.split_time = entry->overall_time;
+	       current.split_size = entry->overall_size;
+	       current.split_bbs = entry->bbs_visited;
+	       consider_split (&current, entry->non_ssa_vars, return_bb);
+	       BITMAP_FREE (current.ssa_names_to_pass);
+	     }
+	}
+      /* Do actual DFS walk.  */
+      if (entry->edge_num
+	  < (EDGE_COUNT (entry->bb->succs)
+	     + EDGE_COUNT (entry->bb->preds)))
+	{
+          edge e;
+	  basic_block dest;
+	  if (entry->edge_num < EDGE_COUNT (entry->bb->succs))
+	    {
+	      e = EDGE_SUCC (entry->bb, entry->edge_num);
+	      dest = e->dest;
+	    }
+	  else
+	    {
+	      e = EDGE_PRED (entry->bb, entry->edge_num
+			     - EDGE_COUNT (entry->bb->succs));
+	      dest = e->src;
+	    }
+
+	  entry->edge_num++;
+
+	  /* New BB to visit, push it to the stack.  */
+	  if (dest != return_bb && dest != EXIT_BLOCK_PTR_FOR_FN (cfun)
+	      && !dest->aux)
+	    {
+	      stack_entry new_entry;
+
+	      new_entry.bb = dest;
+	      new_entry.edge_num = 0;
+	      new_entry.overall_time
+		 = bb_info_vec[dest->index].time;
+	      new_entry.overall_size
+		 = bb_info_vec[dest->index].size;
+	      new_entry.earliest = INT_MAX;
+	      new_entry.set_ssa_names = BITMAP_ALLOC (NULL);
+	      new_entry.used_ssa_names = BITMAP_ALLOC (NULL);
+	      new_entry.bbs_visited = BITMAP_ALLOC (NULL);
+	      new_entry.non_ssa_vars = BITMAP_ALLOC (NULL);
+	      new_entry.can_split = true;
+	      bitmap_set_bit (new_entry.bbs_visited, dest->index);
+	      stack.safe_push (new_entry);
+	      dest->aux = (void *)(intptr_t)stack.length ();
+	    }
+	  /* Back edge found, record the earliest point.  */
+	  else if ((intptr_t)dest->aux > 0
+		   && (intptr_t)dest->aux < entry->earliest)
+	    entry->earliest = (intptr_t)dest->aux;
+	}
+      /* We are done with examining the edges.  Pop off the value from stack
+	 and merge stuff we accumulate during the walk.  */
+      else if (entry->bb != ENTRY_BLOCK_PTR_FOR_FN (cfun))
+	{
+	  stack_entry *prev = &stack[stack.length () - 2];
+
+	  entry->bb->aux = (void *)(intptr_t)-1;
+	  prev->can_split &= entry->can_split;
+	  if (prev->set_ssa_names)
+	    {
+	      bitmap_ior_into (prev->set_ssa_names, entry->set_ssa_names);
+	      bitmap_ior_into (prev->used_ssa_names, entry->used_ssa_names);
+	      bitmap_ior_into (prev->bbs_visited, entry->bbs_visited);
+	      bitmap_ior_into (prev->non_ssa_vars, entry->non_ssa_vars);
+	    }
+	  if (prev->earliest > entry->earliest)
+	    prev->earliest = entry->earliest;
+	  prev->overall_time += entry->overall_time;
+	  prev->overall_size += entry->overall_size;
+	  BITMAP_FREE (entry->set_ssa_names);
+	  BITMAP_FREE (entry->used_ssa_names);
+	  BITMAP_FREE (entry->bbs_visited);
+	  BITMAP_FREE (entry->non_ssa_vars);
+	  stack.pop ();
+	}
+      else
+        stack.pop ();
+    }
+  ENTRY_BLOCK_PTR_FOR_FN (cfun)->aux = NULL;
+  FOR_EACH_BB_FN (bb, cfun)
+    bb->aux = NULL;
+  stack.release ();
+  BITMAP_FREE (current.ssa_names_to_pass);
+}
+
+/* Split function at SPLIT_POINT.  */
+
+static void
+split_function (struct split_point *split_point)
+{
+  vec<tree> args_to_pass = vNULL;
+  bitmap args_to_skip;
+  tree parm;
+  int num = 0;
+  struct cgraph_node *node, *cur_node = cgraph_get_node (current_function_decl);
+  basic_block return_bb = find_return_bb ();
+  basic_block call_bb;
+  gimple_stmt_iterator gsi;
+  gimple call;
+  edge e;
+  edge_iterator ei;
+  tree retval = NULL, real_retval = NULL;
+  bool split_part_return_p = false;
+  gimple last_stmt = NULL;
+  unsigned int i;
+  tree arg, ddef;
+  vec<tree, va_gc> **debug_args = NULL;
+
+  if (dump_file)
+    {
+      fprintf (dump_file, "\n\nSplitting function at:\n");
+      dump_split_point (dump_file, split_point);
+    }
+
+  if (cur_node->local.can_change_signature)
+    args_to_skip = BITMAP_ALLOC (NULL);
+  else
+    args_to_skip = NULL;
+
+  /* Collect the parameters of new function and args_to_skip bitmap.  */
+  for (parm = DECL_ARGUMENTS (current_function_decl);
+       parm; parm = DECL_CHAIN (parm), num++)
+    if (args_to_skip
+	&& (!is_gimple_reg (parm)
+	    || (ddef = ssa_default_def (cfun, parm)) == NULL_TREE
+	    || !bitmap_bit_p (split_point->ssa_names_to_pass,
+			      SSA_NAME_VERSION (ddef))))
+      bitmap_set_bit (args_to_skip, num);
+    else
+      {
+	/* This parm might not have been used up to now, but is going to be
+	   used, hence register it.  */
+	if (is_gimple_reg (parm))
+	  arg = get_or_create_ssa_default_def (cfun, parm);
+	else
+	  arg = parm;
+
+	if (!useless_type_conversion_p (DECL_ARG_TYPE (parm), TREE_TYPE (arg)))
+	  arg = fold_convert (DECL_ARG_TYPE (parm), arg);
+	args_to_pass.safe_push (arg);
+      }
+
+  /* See if the split function will return.  */
+  FOR_EACH_EDGE (e, ei, return_bb->preds)
+    if (bitmap_bit_p (split_point->split_bbs, e->src->index))
+      break;
+  if (e)
+    split_part_return_p = true;
+
+  /* Add return block to what will become the split function.
+     We do not return; no return block is needed.  */
+  if (!split_part_return_p)
+    ;
+  /* We have no return block, so nothing is needed.  */
+  else if (return_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
+    ;
+  /* When we do not want to return value, we need to construct
+     new return block with empty return statement.
+     FIXME: Once we are able to change return type, we should change function
+     to return void instead of just outputting function with undefined return
+     value.  For structures this affects quality of codegen.  */
+  else if (!split_point->split_part_set_retval
+           && find_retval (return_bb))
+    {
+      bool redirected = true;
+      basic_block new_return_bb = create_basic_block (NULL, 0, return_bb);
+      gimple_stmt_iterator gsi = gsi_start_bb (new_return_bb);
+      gsi_insert_after (&gsi, gimple_build_return (NULL), GSI_NEW_STMT);
+      while (redirected)
+	{
+	  redirected = false;
+	  FOR_EACH_EDGE (e, ei, return_bb->preds)
+	    if (bitmap_bit_p (split_point->split_bbs, e->src->index))
+	      {
+		new_return_bb->count += e->count;
+		new_return_bb->frequency += EDGE_FREQUENCY (e);
+		redirect_edge_and_branch (e, new_return_bb);
+		redirected = true;
+		break;
+	      }
+	}
+      e = make_edge (new_return_bb, EXIT_BLOCK_PTR_FOR_FN (cfun), 0);
+      e->probability = REG_BR_PROB_BASE;
+      e->count = new_return_bb->count;
+      if (current_loops)
+	add_bb_to_loop (new_return_bb, current_loops->tree_root);
+      bitmap_set_bit (split_point->split_bbs, new_return_bb->index);
+    }
+  /* When we pass around the value, use existing return block.  */
+  else
+    bitmap_set_bit (split_point->split_bbs, return_bb->index);
+
+  /* If RETURN_BB has virtual operand PHIs, they must be removed and the
+     virtual operand marked for renaming as we change the CFG in a way that
+     tree-inline is not able to compensate for.
+
+     Note this can happen whether or not we have a return value.  If we have
+     a return value, then RETURN_BB may have PHIs for real operands too.  */
+  if (return_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
+    {
+      bool phi_p = false;
+      for (gsi = gsi_start_phis (return_bb); !gsi_end_p (gsi);)
+	{
+	  gimple stmt = gsi_stmt (gsi);
+	  if (!virtual_operand_p (gimple_phi_result (stmt)))
+	    {
+	      gsi_next (&gsi);
+	      continue;
+	    }
+	  mark_virtual_phi_result_for_renaming (stmt);
+	  remove_phi_node (&gsi, true);
+	  phi_p = true;
+	}
+      /* In reality we have to rename the reaching definition of the
+	 virtual operand at return_bb as we will eventually release it
+	 when we remove the code region we outlined.
+	 So we have to rename all immediate virtual uses of that region
+	 if we didn't see a PHI definition yet.  */
+      /* ???  In real reality we want to set the reaching vdef of the
+         entry of the SESE region as the vuse of the call and the reaching
+	 vdef of the exit of the SESE region as the vdef of the call.  */
+      if (!phi_p)
+	for (gsi = gsi_start_bb (return_bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	  {
+	    gimple stmt = gsi_stmt (gsi);
+	    if (gimple_vuse (stmt))
+	      {
+		gimple_set_vuse (stmt, NULL_TREE);
+		update_stmt (stmt);
+	      }
+	    if (gimple_vdef (stmt))
+	      break;
+	  }
+    }
+
+  /* Now create the actual clone.  */
+  rebuild_cgraph_edges ();
+  node = cgraph_function_versioning (cur_node, vNULL,
+				     NULL,
+				     args_to_skip,
+				     !split_part_return_p,
+				     split_point->split_bbs,
+				     split_point->entry_bb, "part");
+
+  /* Let's take a time profile for splitted function.  */
+  node->tp_first_run = cur_node->tp_first_run + 1;
+
+  /* For usual cloning it is enough to clear builtin only when signature
+     changes.  For partial inlining we however can not expect the part
+     of builtin implementation to have same semantic as the whole.  */
+  if (DECL_BUILT_IN (node->decl))
+    {
+      DECL_BUILT_IN_CLASS (node->decl) = NOT_BUILT_IN;
+      DECL_FUNCTION_CODE (node->decl) = (enum built_in_function) 0;
+    }
+  /* If the original function is declared inline, there is no point in issuing
+     a warning for the non-inlinable part.  */
+  DECL_NO_INLINE_WARNING_P (node->decl) = 1;
+  cgraph_node_remove_callees (cur_node);
+  ipa_remove_all_references (&cur_node->ref_list);
+  if (!split_part_return_p)
+    TREE_THIS_VOLATILE (node->decl) = 1;
+  if (dump_file)
+    dump_function_to_file (node->decl, dump_file, dump_flags);
+
+  /* Create the basic block we place call into.  It is the entry basic block
+     split after last label.  */
+  call_bb = split_point->entry_bb;
+  for (gsi = gsi_start_bb (call_bb); !gsi_end_p (gsi);)
+    if (gimple_code (gsi_stmt (gsi)) == GIMPLE_LABEL)
+      {
+	last_stmt = gsi_stmt (gsi);
+	gsi_next (&gsi);
+      }
+    else
+      break;
+  e = split_block (split_point->entry_bb, last_stmt);
+  remove_edge (e);
+
+  /* Produce the call statement.  */
+  gsi = gsi_last_bb (call_bb);
+  FOR_EACH_VEC_ELT (args_to_pass, i, arg)
+    if (!is_gimple_val (arg))
+      {
+	arg = force_gimple_operand_gsi (&gsi, arg, true, NULL_TREE,
+					false, GSI_CONTINUE_LINKING);
+	args_to_pass[i] = arg;
+      }
+  call = gimple_build_call_vec (node->decl, args_to_pass);
+  gimple_set_block (call, DECL_INITIAL (current_function_decl));
+  args_to_pass.release ();
+
+  /* For optimized away parameters, add on the caller side
+     before the call
+     DEBUG D#X => parm_Y(D)
+     stmts and associate D#X with parm in decl_debug_args_lookup
+     vector to say for debug info that if parameter parm had been passed,
+     it would have value parm_Y(D).  */
+  if (args_to_skip)
+    for (parm = DECL_ARGUMENTS (current_function_decl), num = 0;
+	 parm; parm = DECL_CHAIN (parm), num++)
+      if (bitmap_bit_p (args_to_skip, num)
+	  && is_gimple_reg (parm))
+	{
+	  tree ddecl;
+	  gimple def_temp;
+
+	  /* This needs to be done even without MAY_HAVE_DEBUG_STMTS,
+	     otherwise if it didn't exist before, we'd end up with
+	     different SSA_NAME_VERSIONs between -g and -g0.  */
+	  arg = get_or_create_ssa_default_def (cfun, parm);
+	  if (!MAY_HAVE_DEBUG_STMTS)
+	    continue;
+
+	  if (debug_args == NULL)
+	    debug_args = decl_debug_args_insert (node->decl);
+	  ddecl = make_node (DEBUG_EXPR_DECL);
+	  DECL_ARTIFICIAL (ddecl) = 1;
+	  TREE_TYPE (ddecl) = TREE_TYPE (parm);
+	  DECL_MODE (ddecl) = DECL_MODE (parm);
+	  vec_safe_push (*debug_args, DECL_ORIGIN (parm));
+	  vec_safe_push (*debug_args, ddecl);
+	  def_temp = gimple_build_debug_bind (ddecl, unshare_expr (arg),
+					      call);
+	  gsi_insert_after (&gsi, def_temp, GSI_NEW_STMT);
+	}
+  /* And on the callee side, add
+     DEBUG D#Y s=> parm
+     DEBUG var => D#Y
+     stmts to the first bb where var is a VAR_DECL created for the
+     optimized away parameter in DECL_INITIAL block.  This hints
+     in the debug info that var (whole DECL_ORIGIN is the parm PARM_DECL)
+     is optimized away, but could be looked up at the call site
+     as value of D#X there.  */
+  if (debug_args != NULL)
+    {
+      unsigned int i;
+      tree var, vexpr;
+      gimple_stmt_iterator cgsi;
+      gimple def_temp;
+
+      push_cfun (DECL_STRUCT_FUNCTION (node->decl));
+      var = BLOCK_VARS (DECL_INITIAL (node->decl));
+      i = vec_safe_length (*debug_args);
+      cgsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
+      do
+	{
+	  i -= 2;
+	  while (var != NULL_TREE
+		 && DECL_ABSTRACT_ORIGIN (var) != (**debug_args)[i])
+	    var = TREE_CHAIN (var);
+	  if (var == NULL_TREE)
+	    break;
+	  vexpr = make_node (DEBUG_EXPR_DECL);
+	  parm = (**debug_args)[i];
+	  DECL_ARTIFICIAL (vexpr) = 1;
+	  TREE_TYPE (vexpr) = TREE_TYPE (parm);
+	  DECL_MODE (vexpr) = DECL_MODE (parm);
+	  def_temp = gimple_build_debug_source_bind (vexpr, parm,
+						     NULL);
+	  gsi_insert_before (&cgsi, def_temp, GSI_SAME_STMT);
+	  def_temp = gimple_build_debug_bind (var, vexpr, NULL);
+	  gsi_insert_before (&cgsi, def_temp, GSI_SAME_STMT);
+	}
+      while (i);
+      pop_cfun ();
+    }
+
+  /* We avoid address being taken on any variable used by split part,
+     so return slot optimization is always possible.  Moreover this is
+     required to make DECL_BY_REFERENCE work.  */
+  if (aggregate_value_p (DECL_RESULT (current_function_decl),
+			 TREE_TYPE (current_function_decl))
+      && (!is_gimple_reg_type (TREE_TYPE (DECL_RESULT (current_function_decl)))
+	  || DECL_BY_REFERENCE (DECL_RESULT (current_function_decl))))
+    gimple_call_set_return_slot_opt (call, true);
+
+  /* Update return value.  This is bit tricky.  When we do not return,
+     do nothing.  When we return we might need to update return_bb
+     or produce a new return statement.  */
+  if (!split_part_return_p)
+    gsi_insert_after (&gsi, call, GSI_NEW_STMT);
+  else
+    {
+      e = make_edge (call_bb, return_bb,
+		     return_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)
+		     ? 0 : EDGE_FALLTHRU);
+      e->count = call_bb->count;
+      e->probability = REG_BR_PROB_BASE;
+
+      /* If there is return basic block, see what value we need to store
+         return value into and put call just before it.  */
+      if (return_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
+	{
+	  real_retval = retval = find_retval (return_bb);
+
+	  if (real_retval && split_point->split_part_set_retval)
+	    {
+	      gimple_stmt_iterator psi;
+
+	      /* See if we need new SSA_NAME for the result.
+		 When DECL_BY_REFERENCE is true, retval is actually pointer to
+		 return value and it is constant in whole function.  */
+	      if (TREE_CODE (retval) == SSA_NAME
+		  && !DECL_BY_REFERENCE (DECL_RESULT (current_function_decl)))
+		{
+		  retval = copy_ssa_name (retval, call);
+
+		  /* See if there is PHI defining return value.  */
+		  for (psi = gsi_start_phis (return_bb);
+		       !gsi_end_p (psi); gsi_next (&psi))
+		    if (!virtual_operand_p (gimple_phi_result (gsi_stmt (psi))))
+		      break;
+
+		  /* When there is PHI, just update its value.  */
+		  if (TREE_CODE (retval) == SSA_NAME
+		      && !gsi_end_p (psi))
+		    add_phi_arg (gsi_stmt (psi), retval, e, UNKNOWN_LOCATION);
+		  /* Otherwise update the return BB itself.
+		     find_return_bb allows at most one assignment to return value,
+		     so update first statement.  */
+		  else
+		    {
+		      gimple_stmt_iterator bsi;
+		      for (bsi = gsi_start_bb (return_bb); !gsi_end_p (bsi);
+			   gsi_next (&bsi))
+			if (gimple_code (gsi_stmt (bsi)) == GIMPLE_RETURN)
+			  {
+			    gimple_return_set_retval (gsi_stmt (bsi), retval);
+			    break;
+			  }
+			else if (gimple_code (gsi_stmt (bsi)) == GIMPLE_ASSIGN
+				 && !gimple_clobber_p (gsi_stmt (bsi)))
+			  {
+			    gimple_assign_set_rhs1 (gsi_stmt (bsi), retval);
+			    break;
+			  }
+		      update_stmt (gsi_stmt (bsi));
+		    }
+		}
+	      if (DECL_BY_REFERENCE (DECL_RESULT (current_function_decl)))
+		{
+		  gimple_call_set_lhs (call, build_simple_mem_ref (retval));
+		  gsi_insert_after (&gsi, call, GSI_NEW_STMT);
+		}
+	      else
+		{
+		  tree restype;
+		  restype = TREE_TYPE (DECL_RESULT (current_function_decl));
+		  gsi_insert_after (&gsi, call, GSI_NEW_STMT);
+		  if (!useless_type_conversion_p (TREE_TYPE (retval), restype))
+		    {
+		      gimple cpy;
+		      tree tem = create_tmp_reg (restype, NULL);
+		      tem = make_ssa_name (tem, call);
+		      cpy = gimple_build_assign_with_ops (NOP_EXPR, retval,
+							  tem, NULL_TREE);
+		      gsi_insert_after (&gsi, cpy, GSI_NEW_STMT);
+		      retval = tem;
+		    }
+		  gimple_call_set_lhs (call, retval);
+		  update_stmt (call);
+		}
+	    }
+	  else
+	    gsi_insert_after (&gsi, call, GSI_NEW_STMT);
+	}
+      /* We don't use return block (there is either no return in function or
+	 multiple of them).  So create new basic block with return statement.
+	 */
+      else
+	{
+	  gimple ret;
+	  if (split_point->split_part_set_retval
+	      && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (current_function_decl))))
+	    {
+	      retval = DECL_RESULT (current_function_decl);
+
+	      /* We use temporary register to hold value when aggregate_value_p
+		 is false.  Similarly for DECL_BY_REFERENCE we must avoid extra
+		 copy.  */
+	      if (!aggregate_value_p (retval, TREE_TYPE (current_function_decl))
+		  && !DECL_BY_REFERENCE (retval))
+		retval = create_tmp_reg (TREE_TYPE (retval), NULL);
+	      if (is_gimple_reg (retval))
+		{
+		  /* When returning by reference, there is only one SSA name
+		     assigned to RESULT_DECL (that is pointer to return value).
+		     Look it up or create new one if it is missing.  */
+		  if (DECL_BY_REFERENCE (retval))
+		    retval = get_or_create_ssa_default_def (cfun, retval);
+		  /* Otherwise produce new SSA name for return value.  */
+		  else
+		    retval = make_ssa_name (retval, call);
+		}
+	      if (DECL_BY_REFERENCE (DECL_RESULT (current_function_decl)))
+	        gimple_call_set_lhs (call, build_simple_mem_ref (retval));
+	      else
+	        gimple_call_set_lhs (call, retval);
+	    }
+          gsi_insert_after (&gsi, call, GSI_NEW_STMT);
+	  ret = gimple_build_return (retval);
+	  gsi_insert_after (&gsi, ret, GSI_NEW_STMT);
+	}
+    }
+  free_dominance_info (CDI_DOMINATORS);
+  free_dominance_info (CDI_POST_DOMINATORS);
+  compute_inline_parameters (node, true);
+}
+
+/* Execute function splitting pass.  */
+
+static unsigned int
+execute_split_functions (void)
+{
+  gimple_stmt_iterator bsi;
+  basic_block bb;
+  int overall_time = 0, overall_size = 0;
+  int todo = 0;
+  struct cgraph_node *node = cgraph_get_node (current_function_decl);
+
+  if (flags_from_decl_or_type (current_function_decl)
+      & (ECF_NORETURN|ECF_MALLOC))
+    {
+      if (dump_file)
+	fprintf (dump_file, "Not splitting: noreturn/malloc function.\n");
+      return 0;
+    }
+  if (MAIN_NAME_P (DECL_NAME (current_function_decl)))
+    {
+      if (dump_file)
+	fprintf (dump_file, "Not splitting: main function.\n");
+      return 0;
+    }
+  /* This can be relaxed; function might become inlinable after splitting
+     away the uninlinable part.  */
+  if (inline_edge_summary_vec.exists ()
+      && !inline_summary (node)->inlinable)
+    {
+      if (dump_file)
+	fprintf (dump_file, "Not splitting: not inlinable.\n");
+      return 0;
+    }
+  if (DECL_DISREGARD_INLINE_LIMITS (node->decl))
+    {
+      if (dump_file)
+	fprintf (dump_file, "Not splitting: disregarding inline limits.\n");
+      return 0;
+    }
+  /* This can be relaxed; most of versioning tests actually prevents
+     a duplication.  */
+  if (!tree_versionable_function_p (current_function_decl))
+    {
+      if (dump_file)
+	fprintf (dump_file, "Not splitting: not versionable.\n");
+      return 0;
+    }
+  /* FIXME: we could support this.  */
+  if (DECL_STRUCT_FUNCTION (current_function_decl)->static_chain_decl)
+    {
+      if (dump_file)
+	fprintf (dump_file, "Not splitting: nested function.\n");
+      return 0;
+    }
+
+  /* See if it makes sense to try to split.
+     It makes sense to split if we inline, that is if we have direct calls to
+     handle or direct calls are possibly going to appear as result of indirect
+     inlining or LTO.  Also handle -fprofile-generate as LTO to allow non-LTO
+     training for LTO -fprofile-use build.
+
+     Note that we are not completely conservative about disqualifying functions
+     called once.  It is possible that the caller is called more then once and
+     then inlining would still benefit.  */
+  if ((!node->callers
+       /* Local functions called once will be completely inlined most of time.  */
+       || (!node->callers->next_caller && node->local.local))
+      && !node->address_taken
+      && (!flag_lto || !node->externally_visible))
+    {
+      if (dump_file)
+	fprintf (dump_file, "Not splitting: not called directly "
+		 "or called once.\n");
+      return 0;
+    }
+
+  /* FIXME: We can actually split if splitting reduces call overhead.  */
+  if (!flag_inline_small_functions
+      && !DECL_DECLARED_INLINE_P (current_function_decl))
+    {
+      if (dump_file)
+	fprintf (dump_file, "Not splitting: not autoinlining and function"
+		 " is not inline.\n");
+      return 0;
+    }
+
+  /* We enforce splitting after loop headers when profile info is not
+     available.  */
+  if (profile_status_for_fn (cfun) != PROFILE_READ)
+    mark_dfs_back_edges ();
+
+  /* Initialize bitmap to track forbidden calls.  */
+  forbidden_dominators = BITMAP_ALLOC (NULL);
+  calculate_dominance_info (CDI_DOMINATORS);
+
+  /* Compute local info about basic blocks and determine function size/time.  */
+  bb_info_vec.safe_grow_cleared (last_basic_block_for_fn (cfun) + 1);
+  memset (&best_split_point, 0, sizeof (best_split_point));
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      int time = 0;
+      int size = 0;
+      int freq = compute_call_stmt_bb_frequency (current_function_decl, bb);
+
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, "Basic block %i\n", bb->index);
+
+      for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
+	{
+	  int this_time, this_size;
+	  gimple stmt = gsi_stmt (bsi);
+
+	  this_size = estimate_num_insns (stmt, &eni_size_weights);
+	  this_time = estimate_num_insns (stmt, &eni_time_weights) * freq;
+	  size += this_size;
+	  time += this_time;
+	  check_forbidden_calls (stmt);
+
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fprintf (dump_file, "  freq:%6i size:%3i time:%3i ",
+		       freq, this_size, this_time);
+	      print_gimple_stmt (dump_file, stmt, 0, 0);
+	    }
+	}
+      overall_time += time;
+      overall_size += size;
+      bb_info_vec[bb->index].time = time;
+      bb_info_vec[bb->index].size = size;
+    }
+  find_split_points (overall_time, overall_size);
+  if (best_split_point.split_bbs)
+    {
+      split_function (&best_split_point);
+      BITMAP_FREE (best_split_point.ssa_names_to_pass);
+      BITMAP_FREE (best_split_point.split_bbs);
+      todo = TODO_update_ssa | TODO_cleanup_cfg;
+    }
+  BITMAP_FREE (forbidden_dominators);
+  bb_info_vec.release ();
+  return todo;
+}
+
+/* Gate function splitting pass.  When doing profile feedback, we want
+   to execute the pass after profiling is read.  So disable one in 
+   early optimization.  */
+
+static bool
+gate_split_functions (void)
+{
+  return (flag_partial_inlining
+	  && !profile_arc_flag && !flag_branch_probabilities);
+}
+
+namespace {
+
+const pass_data pass_data_split_functions =
+{
+  GIMPLE_PASS, /* type */
+  "fnsplit", /* name */
+  OPTGROUP_NONE, /* optinfo_flags */
+  true, /* has_gate */
+  true, /* has_execute */
+  TV_IPA_FNSPLIT, /* tv_id */
+  PROP_cfg, /* properties_required */
+  0, /* properties_provided */
+  0, /* properties_destroyed */
+  0, /* todo_flags_start */
+  TODO_verify_all, /* todo_flags_finish */
+};
+
+class pass_split_functions : public gimple_opt_pass
+{
+public:
+  pass_split_functions (gcc::context *ctxt)
+    : gimple_opt_pass (pass_data_split_functions, ctxt)
+  {}
+
+  /* opt_pass methods: */
+  bool gate () { return gate_split_functions (); }
+  unsigned int execute () { return execute_split_functions (); }
+
+}; // class pass_split_functions
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pass_split_functions (gcc::context *ctxt)
+{
+  return new pass_split_functions (ctxt);
+}
+
+/* Gate feedback driven function splitting pass.
+   We don't need to split when profiling at all, we are producing
+   lousy code anyway.  */
+
+static bool
+gate_feedback_split_functions (void)
+{
+  return (flag_partial_inlining
+	  && flag_branch_probabilities);
+}
+
+/* Execute function splitting pass.  */
+
+static unsigned int
+execute_feedback_split_functions (void)
+{
+  unsigned int retval = execute_split_functions ();
+  if (retval)
+    retval |= TODO_rebuild_cgraph_edges;
+  return retval;
+}
+
+namespace {
+
+const pass_data pass_data_feedback_split_functions =
+{
+  GIMPLE_PASS, /* type */
+  "feedback_fnsplit", /* name */
+  OPTGROUP_NONE, /* optinfo_flags */
+  true, /* has_gate */
+  true, /* has_execute */
+  TV_IPA_FNSPLIT, /* tv_id */
+  PROP_cfg, /* properties_required */
+  0, /* properties_provided */
+  0, /* properties_destroyed */
+  0, /* todo_flags_start */
+  TODO_verify_all, /* todo_flags_finish */
+};
+
+class pass_feedback_split_functions : public gimple_opt_pass
+{
+public:
+  pass_feedback_split_functions (gcc::context *ctxt)
+    : gimple_opt_pass (pass_data_feedback_split_functions, ctxt)
+  {}
+
+  /* opt_pass methods: */
+  bool gate () { return gate_feedback_split_functions (); }
+  unsigned int execute () { return execute_feedback_split_functions (); }
+
+}; // class pass_feedback_split_functions
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pass_feedback_split_functions (gcc::context *ctxt)
+{
+  return new pass_feedback_split_functions (ctxt);
+}