CbC/CbC_gcc: gcc/ipa-split.c comparison

comparison gcc/ipa-split.c @ 68:561a7518be6b

update gcc-4.6

author	Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
date	Sun, 21 Aug 2011 07:07:55 +0900
parents
children	04ced10e8804

comparison

equal deleted inserted replaced

-:f6334be47118
+:561a7518be6b
+/* Function splitting pass
+Copyright (C) 2010, 2011
+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 "target.h"
+#include "cgraph.h"
+#include "ipa-prop.h"
+#include "tree-flow.h"
+#include "tree-pass.h"
+#include "flags.h"
+#include "timevar.h"
+#include "diagnostic.h"
+#include "tree-dump.h"
+#include "tree-inline.h"
+#include "fibheap.h"
+#include "params.h"
+#include "gimple-pretty-print.h"
+/* Per basic block info.  */
+typedef struct
+{
+unsigned int size;
+unsigned int time;
+} bb_info;
+DEF_VEC_O(bb_info);
+DEF_VEC_ALLOC_O(bb_info,heap);
+static VEC(bb_info, heap) *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;
+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 stmt ATTRIBUTE_UNUSED, tree t, 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
+&& 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 header time:%i header size: %i"
+	   " 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,heap) *worklist = NULL;
+edge e;
+edge_iterator ei;
+bool ok = true;
+FOR_EACH_EDGE (e, ei, current->entry_bb->preds)
+if (e->src != ENTRY_BLOCK_PTR
+	&& !bitmap_bit_p (current->split_bbs, e->src->index))
+{
+VEC_safe_push (basic_block, heap, worklist, e->src);
+	bitmap_set_bit (seen, e->src->index);
+}
+while (!VEC_empty (basic_block, worklist))
+{
+gimple_stmt_iterator bsi;
+basic_block bb = VEC_pop (basic_block, worklist);
+FOR_EACH_EDGE (e, ei, bb->preds)
+	if (e->src != ENTRY_BLOCK_PTR
+	    && bitmap_set_bit (seen, e->src->index))
+	  {
+	    gcc_checking_assert (!bitmap_bit_p (current->split_bbs,
+					        e->src->index));
+	    VEC_safe_push (basic_block, heap, worklist, 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),
+				  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 (!is_gimple_reg (gimple_phi_result (stmt)))
+		continue;
+	      if (TREE_CODE (op) != SSA_NAME
+		  && test_nonssa_use (stmt, op, non_ssa_vars))
+		{
+		  ok = false;
+		  goto done;
+		}
+	    }
+	}
+}
+done:
+BITMAP_FREE (seen);
+VEC_free (basic_block, heap, worklist);
+return ok;
+}
+/* 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;
+if (dump_file && (dump_flags & TDF_DETAILS))
+dump_split_point (dump_file, current);
+FOR_EACH_EDGE (e, ei, current->entry_bb->preds)
+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->frequency
+	  * PARAM_VALUE (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY) / 100))
+{
+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 (!is_gimple_reg (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 if (gimple_default_def (cfun, parm)
+	       && bitmap_bit_p (current->ssa_names_to_pass,
+				SSA_NAME_VERSION (gimple_default_def
+						  (cfun, parm))))
+	{
+	  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;
+}
+/* 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
+	   && 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)
+{
+gimple_stmt_iterator psi;
+for (psi = gsi_start_phis (return_bb); !gsi_end_p (psi); gsi_next (&psi))
+	if (is_gimple_reg (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 EXIT_BLOCK_PTR.
+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;
+gimple_stmt_iterator bsi;
+bool found_return = false;
+tree retval = NULL_TREE;
+if (!single_pred_p (EXIT_BLOCK_PTR))
+return return_bb;
+e = single_pred_edge (EXIT_BLOCK_PTR);
+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))
+	;
+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)
+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 stmt ATTRIBUTE_UNUSED, tree t, 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
+&& 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;
+/* 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 (is_gimple_debug (stmt))
+	continue;
+if (!is_gimple_reg (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 (is_gimple_debug (stmt))
+	      continue;
+	    if (!is_gimple_reg (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, 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;
+DEF_VEC_O(stack_entry);
+DEF_VEC_ALLOC_O(stack_entry,heap);
+/* 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, heap) *stack = NULL;
+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;
+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.bbs_visited = 0;
+VEC_safe_push (stack_entry, heap, stack, &first);
+ENTRY_BLOCK_PTR->aux = (void *)(intptr_t)-1;
+while (!VEC_empty (stack_entry, stack))
+{
+stack_entry *entry = VEC_last (stack_entry, stack);
+/* 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)
+	{
+	  int pos = VEC_length (stack_entry, stack);
+	  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
+	      && !dest->aux)
+	    {
+	      stack_entry new_entry;
+	      new_entry.bb = dest;
+	      new_entry.edge_num = 0;
+	      new_entry.overall_time
+		 = VEC_index (bb_info, bb_info_vec, dest->index)->time;
+	      new_entry.overall_size
+		 = VEC_index (bb_info, 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);
+	      VEC_safe_push (stack_entry, heap, stack, &new_entry);
+	      dest->aux = (void *)(intptr_t)VEC_length (stack_entry, stack);
+	    }
+	  /* 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)
+	{
+	  stack_entry *prev = VEC_index (stack_entry, stack,
+					 VEC_length (stack_entry, stack) - 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);
+	  VEC_pop (stack_entry, stack);
+	}
+else
+VEC_pop (stack_entry, stack);
+}
+ENTRY_BLOCK_PTR->aux = NULL;
+FOR_EACH_BB (bb)
+bb->aux = NULL;
+VEC_free (stack_entry, heap, stack);
+BITMAP_FREE (current.ssa_names_to_pass);
+}
+/* Split function at SPLIT_POINT.  */
+static void
+split_function (struct split_point *split_point)
+{
+VEC (tree, heap) *args_to_pass = NULL;
+bitmap args_to_skip = BITMAP_ALLOC (NULL);
+tree parm;
+int num = 0;
+struct cgraph_node *node;
+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;
+bool conv_needed = false;
+unsigned int i;
+tree arg;
+if (dump_file)
+{
+fprintf (dump_file, "\n\nSplitting function at:\n");
+dump_split_point (dump_file, split_point);
+}
+/* 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 (!is_gimple_reg (parm)
+	|| !gimple_default_def (cfun, parm)
+	|| !bitmap_bit_p (split_point->ssa_names_to_pass,
+			  SSA_NAME_VERSION (gimple_default_def (cfun, parm))))
+bitmap_set_bit (args_to_skip, num);
+else
+{
+	arg = gimple_default_def (cfun, parm);
+	if (TYPE_MAIN_VARIANT (DECL_ARG_TYPE (parm))
+	    != TYPE_MAIN_VARIANT (TREE_TYPE (arg)))
+	  {
+	    conv_needed = true;
+	    arg = fold_convert (DECL_ARG_TYPE (parm), arg);
+	  }
+	VEC_safe_push (tree, heap, args_to_pass, 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)
+;
+/* 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, 0);
+e->probability = REG_BR_PROB_BASE;
+e->count = new_return_bb->count;
+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 (gsi = gsi_start_phis (return_bb); !gsi_end_p (gsi);)
+	{
+	  gimple stmt = gsi_stmt (gsi);
+	  if (is_gimple_reg (gimple_phi_result (stmt)))
+	    {
+	      gsi_next (&gsi);
+	      continue;
+	    }
+	  mark_virtual_phi_result_for_renaming (stmt);
+	  remove_phi_node (&gsi, true);
+	}
+}
+/* Now create the actual clone.  */
+rebuild_cgraph_edges ();
+node = cgraph_function_versioning (cgraph_node (current_function_decl),
+				     NULL, NULL,
+				     args_to_skip,
+				     split_point->split_bbs,
+				     split_point->entry_bb, "part");
+/* 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;
+}
+cgraph_node_remove_callees (cgraph_node (current_function_decl));
+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);
+if (conv_needed)
+FOR_EACH_VEC_ELT (tree, args_to_pass, i, arg)
+if (!is_gimple_val (arg))
+	{
+	  arg = force_gimple_operand_gsi (&gsi, arg, true, NULL_TREE,
+					  false, GSI_NEW_STMT);
+	  VEC_replace (tree, args_to_pass, i, arg);
+	}
+call = gimple_build_call_vec (node->decl, args_to_pass);
+gimple_set_block (call, DECL_INITIAL (current_function_decl));
+/* 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)))
+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 ? 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)
+	{
+	  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 = make_ssa_name (SSA_NAME_VAR (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 (is_gimple_reg (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_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));
+	      else
+	        gimple_call_set_lhs (call, retval);
+	    }
+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))
+		    {
+		      tree retval_name;
+		      if ((retval_name = gimple_default_def (cfun, retval))
+			  != NULL)
+			retval = retval_name;
+		      else
+			{
+		          retval_name = make_ssa_name (retval,
+						       gimple_build_nop ());
+			  set_default_def (retval, retval_name);
+			  retval = retval_name;
+			}
+		    }
+		  /* 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);
+}
+/* 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_node (current_function_decl);
+if (flags_from_decl_or_type (current_function_decl) & ECF_NORETURN)
+{
+if (dump_file)
+	fprintf (dump_file, "Not splitting: noreturn 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 (!node->local.inlinable)
+{
+if (dump_file)
+	fprintf (dump_file, "Not splitting: not inlinable.\n");
+return 0;
+}
+if (node->local.disregard_inline_limits)
+{
+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 || !node->callers->next_caller)
+&& !node->address_taken
+&& (!flag_lto || !node->local.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;
+}
+/* Compute local info about basic blocks and determine function size/time.  */
+VEC_safe_grow_cleared (bb_info, heap, bb_info_vec, last_basic_block + 1);
+memset (&best_split_point, 0, sizeof (best_split_point));
+FOR_EACH_BB (bb)
+{
+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;
+	  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;
+VEC_index (bb_info, bb_info_vec, bb->index)->time = time;
+VEC_index (bb_info, 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;
+}
+VEC_free (bb_info, heap, bb_info_vec);
+bb_info_vec = NULL;
+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);
+}
+struct gimple_opt_pass pass_split_functions =
+{
+{
+GIMPLE_PASS,
+"fnsplit",				/* name */
+gate_split_functions,			/* gate */
+execute_split_functions,		/* execute */
+NULL,					/* sub */
+NULL,					/* next */
+0,					/* static_pass_number */
+TV_IPA_FNSPLIT,			/* tv_id */
+PROP_cfg,				/* properties_required */
+0,					/* properties_provided */
+0,					/* properties_destroyed */
+0,					/* todo_flags_start */
+TODO_dump_func			/* todo_flags_finish */
+}
+};
+/* 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;
+}
+struct gimple_opt_pass pass_feedback_split_functions =
+{
+{
+GIMPLE_PASS,
+"feedback_fnsplit",			/* name */
+gate_feedback_split_functions,	/* gate */
+execute_feedback_split_functions,	/* execute */
+NULL,					/* sub */
+NULL,					/* next */
+0,					/* static_pass_number */
+TV_IPA_FNSPLIT,			/* tv_id */
+PROP_cfg,				/* properties_required */
+0,					/* properties_provided */
+0,					/* properties_destroyed */
+0,					/* todo_flags_start */
+TODO_dump_func			/* todo_flags_finish */
+}
+};

Mercurial > hg > CbC > CbC_gcc

comparison gcc/ipa-split.c @ 68:561a7518be6b