vec.h (FOR_EACH_VEC_ELT_REVERSE): New macro.

gcc/
	* vec.h (FOR_EACH_VEC_ELT_REVERSE): New macro.
	* function.h (struct_function): Change type of local_decls field
	to a VEC.
	(add_local_decl): New function.
	(FOR_EACH_LOCAL_DECL): New macro.
	* cfgexpand.c (init_vars_expansion): Adjust for new type of
	cfun->local_decls.
	(estimated_stack_frame_size): Likewise.
	(expand_used_vars): Likewise.
	* cgraphbuild.c (build_cgraph_edges): Likewise.
	* function.c (instantiate_decls_1): Likewise.
	* ipa-struct-reorg.c (build_data_structure): Likewise.
	* ipa-type-escape.c (analyze_function): Likewise.
	* lto-streamer-in.c (input_function): Likewise.
	* lto-streamer-out.c (output_function): Likewise.
	* tree-ssa-live.c (remove_unused_locals): Likewise.
	* tree.c (free_lang_data_in_decl): Likewise.
	(find_decls_types_in_node): Likewise.
	* omp-low.c (remove_exit_barrier): Likewise.
	(expand_omp_taskreg): Likewise.
	(list2chain): Rename to...
	(vec2chain): ...this.  Adjust.
	* cgraphunit.c (assemble_thunk): Call add_local_decl.
	* tree-cfg.c (replace_by_duplicate_decl): Likewise.
	* gimple-low.c (record_vars_into): Likewise.
	* tree-inline.c (remap_decls): Likewise.
	(declare_return_variable): Likewise.
	(declare_inline_vars): Likewise.
	(copy_forbidden): Adjust for new type of cfun->local_decls.
	(add_local_variables): New function.
	(expand_call_inline): Call it.
	(tree_function_versioning): Likewise.

gcc/cp/
	* decl.c (cp_finish_decl): Call add_local_decl.
	* optimize.c (clone_body): Adjust for new type of cfun->local_decls.

From-SVN: r161862

20 files changed, 233 insertions, 202 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 333e045..156b55a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,38 @@
+2010-07-05  Nathan Froyd  <froydnj@codesourcery.com>
+
+	* vec.h (FOR_EACH_VEC_ELT_REVERSE): New macro.
+	* function.h (struct_function): Change type of local_decls field
+	to a VEC.
+	(add_local_decl): New function.
+	(FOR_EACH_LOCAL_DECL): New macro.
+	* cfgexpand.c (init_vars_expansion): Adjust for new type of
+	cfun->local_decls.
+	(estimated_stack_frame_size): Likewise.
+	(expand_used_vars): Likewise.
+	* cgraphbuild.c (build_cgraph_edges): Likewise.
+	* function.c (instantiate_decls_1): Likewise.
+	* ipa-struct-reorg.c (build_data_structure): Likewise.
+	* ipa-type-escape.c (analyze_function): Likewise.
+	* lto-streamer-in.c (input_function): Likewise.
+	* lto-streamer-out.c (output_function): Likewise.
+	* tree-ssa-live.c (remove_unused_locals): Likewise.
+	* tree.c (free_lang_data_in_decl): Likewise.
+	(find_decls_types_in_node): Likewise.
+	* omp-low.c (remove_exit_barrier): Likewise.
+	(expand_omp_taskreg): Likewise.
+	(list2chain): Rename to...
+	(vec2chain): ...this.  Adjust.
+	* cgraphunit.c (assemble_thunk): Call add_local_decl.
+	* tree-cfg.c (replace_by_duplicate_decl): Likewise.
+	* gimple-low.c (record_vars_into): Likewise.
+	* tree-inline.c (remap_decls): Likewise.
+	(declare_return_variable): Likewise.
+	(declare_inline_vars): Likewise.
+	(copy_forbidden): Adjust for new type of cfun->local_decls.
+	(add_local_variables): New function.
+	(expand_call_inline): Call it.
+	(tree_function_versioning): Likewise.
+
 2010-07-05  H.J. Lu  <hongjiu.lu@intel.com>
 
 	AVX Programming Reference (June, 2010)
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index 3e9ecbf..5b0596e 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -1226,9 +1226,10 @@ static void
 init_vars_expansion (void)
 {
   tree t;
+  unsigned ix;
   /* Set TREE_USED on all variables in the local_decls.  */
-  for (t = cfun->local_decls; t; t = TREE_CHAIN (t))
-    TREE_USED (TREE_VALUE (t)) = 1;
+  FOR_EACH_LOCAL_DECL (cfun, ix, t)
+    TREE_USED (t) = 1;
 
   /* Clear TREE_USED on all variables associated with a block scope.  */
   clear_tree_used (DECL_INITIAL (current_function_decl));
@@ -1264,14 +1265,13 @@ estimated_stack_frame_size (void)
 {
   HOST_WIDE_INT size = 0;
   size_t i;
-  tree t, outer_block = DECL_INITIAL (current_function_decl);
+  tree var, outer_block = DECL_INITIAL (current_function_decl);
+  unsigned ix;
 
   init_vars_expansion ();
 
-  for (t = cfun->local_decls; t; t = TREE_CHAIN (t))
+  FOR_EACH_LOCAL_DECL (cfun, ix, var)
     {
-      tree var = TREE_VALUE (t);
-
       if (TREE_USED (var))
         size += expand_one_var (var, true, false);
       TREE_USED (var) = 1;
@@ -1296,9 +1296,10 @@ estimated_stack_frame_size (void)
 static void
 expand_used_vars (void)
 {
-  tree t, next, outer_block = DECL_INITIAL (current_function_decl);
-  tree maybe_local_decls = NULL_TREE;
+  tree var, outer_block = DECL_INITIAL (current_function_decl);
+  VEC(tree,heap) *maybe_local_decls = NULL;
   unsigned i;
+  unsigned len;
 
   /* Compute the phase of the stack frame for this function.  */
   {
@@ -1333,15 +1334,12 @@ expand_used_vars (void)
 
   /* At this point all variables on the local_decls with TREE_USED
      set are not associated with any block scope.  Lay them out.  */
-  t = cfun->local_decls;
-  cfun->local_decls = NULL_TREE;
-  for (; t; t = next)
+
+  len = VEC_length (tree, cfun->local_decls);
+  FOR_EACH_LOCAL_DECL (cfun, i, var)
     {
-      tree var = TREE_VALUE (t);
       bool expand_now = false;
 
-      next = TREE_CHAIN (t);
-
       /* Expanded above already.  */
       if (is_gimple_reg (var))
 	{
@@ -1377,25 +1375,29 @@ expand_used_vars (void)
 	  /* Keep artificial non-ignored vars in cfun->local_decls
 	     chain until instantiate_decls.  */
 	  if (rtl && (MEM_P (rtl) || GET_CODE (rtl) == CONCAT))
-	    {
-	      TREE_CHAIN (t) = cfun->local_decls;
-	      cfun->local_decls = t;
-	      continue;
-	    }
+	    add_local_decl (cfun, var);
 	  else if (rtl == NULL_RTX)
-	    {
-	      /* If rtl isn't set yet, which can happen e.g. with
-		 -fstack-protector, retry before returning from this
-		 function.  */
-	      TREE_CHAIN (t) = maybe_local_decls;
-	      maybe_local_decls = t;
-	      continue;
-	    }
+	    /* If rtl isn't set yet, which can happen e.g. with
+	       -fstack-protector, retry before returning from this
+	       function.  */
+	    VEC_safe_push (tree, heap, maybe_local_decls, var);
 	}
-
-      ggc_free (t);
     }
 
+  /* We duplicated some of the decls in CFUN->LOCAL_DECLS.
+
+     +-----------------+-----------------+
+     | ...processed... | ...duplicates...|
+     +-----------------+-----------------+
+                       ^
+		       +-- LEN points here.
+
+     We just want the duplicates, as those are the artificial
+     non-ignored vars that we want to keep until instantiate_decls.
+     Move them down and truncate the array.  */
+  if (!VEC_empty (tree, cfun->local_decls))
+    VEC_block_remove (tree, cfun->local_decls, 0, len);
+
   /* At this point, all variables within the block tree with TREE_USED
      set are actually used by the optimized function.  Lay them out.  */
   expand_used_vars_for_block (outer_block, true);
@@ -1452,24 +1454,16 @@ expand_used_vars (void)
   /* If there were any artificial non-ignored vars without rtl
      found earlier, see if deferred stack allocation hasn't assigned
      rtl to them.  */
-  for (t = maybe_local_decls; t; t = next)
+  FOR_EACH_VEC_ELT_REVERSE (tree, maybe_local_decls, i, var)
     {
-      tree var = TREE_VALUE (t);
       rtx rtl = DECL_RTL_IF_SET (var);
 
-      next = TREE_CHAIN (t);
-
       /* Keep artificial non-ignored vars in cfun->local_decls
 	 chain until instantiate_decls.  */
       if (rtl && (MEM_P (rtl) || GET_CODE (rtl) == CONCAT))
-	{
-	  TREE_CHAIN (t) = cfun->local_decls;
-	  cfun->local_decls = t;
-	  continue;
-	}
-
-      ggc_free (t);
+	add_local_decl (cfun, var);
     }
+  VEC_free (tree, heap, maybe_local_decls);
 
   /* If the target requires that FRAME_OFFSET be aligned, do it.  */
   if (STACK_ALIGNMENT_NEEDED)
diff --git a/gcc/cgraphbuild.c b/gcc/cgraphbuild.c
index 9dcb862..3bd42e3 100644
--- a/gcc/cgraphbuild.c
+++ b/gcc/cgraphbuild.c
@@ -328,7 +328,8 @@ build_cgraph_edges (void)
   struct cgraph_node *node = cgraph_node (current_function_decl);
   struct pointer_set_t *visited_nodes = pointer_set_create ();
   gimple_stmt_iterator gsi;
-  tree step;
+  tree decl;
+  unsigned ix;
 
   /* Create the callgraph edges and record the nodes referenced by the function.
      body.  */
@@ -378,15 +379,10 @@ build_cgraph_edges (void)
    }
 
   /* Look for initializers of constant variables and private statics.  */
-  for (step = cfun->local_decls;
-       step;
-       step = TREE_CHAIN (step))
-    {
-      tree decl = TREE_VALUE (step);
-      if (TREE_CODE (decl) == VAR_DECL
-	  && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl)))
-	varpool_finalize_decl (decl);
-    }
+  FOR_EACH_LOCAL_DECL (cfun, ix, decl)
+    if (TREE_CODE (decl) == VAR_DECL
+	&& (TREE_STATIC (decl) && !DECL_EXTERNAL (decl)))
+      varpool_finalize_decl (decl);
   record_eh_tables (node, cfun);
 
   pointer_set_destroy (visited_nodes);
diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index 2988f1c..da1f983 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -1520,7 +1520,7 @@ assemble_thunk (struct cgraph_node *node)
 	  if (!is_gimple_reg_type (restype))
 	    {
 	      restmp = resdecl;
-	      cfun->local_decls = tree_cons (NULL_TREE, restmp, cfun->local_decls);
+	      add_local_decl (cfun, restmp);
 	      BLOCK_VARS (DECL_INITIAL (current_function_decl)) = restmp;
 	    }
 	  else
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 4790208..3f2cac1 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2010-07-05  Nathan Froyd  <froydnj@codesourcery.com>
+
+	* decl.c (cp_finish_decl): Call add_local_decl.
+	* optimize.c (clone_body): Adjust for new type of cfun->local_decls.
+
 2010-07-05  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* pt.c (tsubst): Early declare code = TREE_CODE (t) and use it
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 1d11fb8..541f77e 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -5838,8 +5838,7 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
 	       but [cd]tors are never actually compiled directly.  We need
 	       to put statics on the list so we can deal with the label
 	       address extension.  */
-	    cfun->local_decls = tree_cons (NULL_TREE, decl,
-					   cfun->local_decls);
+	    add_local_decl (cfun, decl);
 	}
 
       /* Convert the initializer to the type of DECL, if we have not
diff --git a/gcc/cp/optimize.c b/gcc/cp/optimize.c
index 0196eae..7ec2034 100644
--- a/gcc/cp/optimize.c
+++ b/gcc/cp/optimize.c
@@ -107,12 +107,11 @@ clone_body (tree clone, tree fn, void *arg_map)
   if (DECL_NAME (clone) == base_dtor_identifier
       || DECL_NAME (clone) == base_ctor_identifier)
     {
-      tree decls = DECL_STRUCT_FUNCTION (fn)->local_decls;
-      for (; decls; decls = TREE_CHAIN (decls))
-	{
-	  tree decl = TREE_VALUE (decls);
-	  walk_tree (&DECL_INITIAL (decl), copy_tree_body_r, &id, NULL);
-	}
+      unsigned ix;
+      tree decl;
+
+      FOR_EACH_LOCAL_DECL (DECL_STRUCT_FUNCTION (fn), ix, decl)
+        walk_tree (&DECL_INITIAL (decl), copy_tree_body_r, &id, NULL);
     }
 
   append_to_statement_list_force (stmts, &DECL_SAVED_TREE (clone));
diff --git a/gcc/function.c b/gcc/function.c
index 3a7bb25..9075e08 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -1815,7 +1815,8 @@ instantiate_decls_1 (tree let)
 static void
 instantiate_decls (tree fndecl)
 {
-  tree decl, t, next;
+  tree decl;
+  unsigned ix;
 
   /* Process all parameters of the function.  */
   for (decl = DECL_ARGUMENTS (fndecl); decl; decl = TREE_CHAIN (decl))
@@ -1832,16 +1833,10 @@ instantiate_decls (tree fndecl)
   /* Now process all variables defined in the function or its subblocks.  */
   instantiate_decls_1 (DECL_INITIAL (fndecl));
 
-  t = cfun->local_decls;
-  cfun->local_decls = NULL_TREE;
-  for (; t; t = next)
-    {
-      next = TREE_CHAIN (t);
-      decl = TREE_VALUE (t);
-      if (DECL_RTL_SET_P (decl))
-	instantiate_decl_rtl (DECL_RTL (decl));
-      ggc_free (t);
-    }
+  FOR_EACH_LOCAL_DECL (cfun, ix, decl)
+    if (DECL_RTL_SET_P (decl))
+      instantiate_decl_rtl (DECL_RTL (decl));
+  VEC_free (tree, gc, cfun->local_decls);
 }
 
 /* Pass through the INSNS of function FNDECL and convert virtual register
diff --git a/gcc/function.h b/gcc/function.h
index 6170348..fec0168 100644
--- a/gcc/function.h
+++ b/gcc/function.h
@@ -503,8 +503,8 @@ struct GTY(()) function {
      pointer.  */
   tree nonlocal_goto_save_area;
 
-  /* List of function local variables, functions, types and constants.  */
-  tree local_decls;
+  /* Vector of function local variables, functions, types and constants.  */
+  VEC(tree,gc) *local_decls;
 
   /* For md files.  */
 
@@ -609,6 +609,17 @@ struct GTY(()) function {
   unsigned int is_thunk : 1;
 };
 
+/* Add the decl D to the local_decls list of FUN.  */
+
+static inline void
+add_local_decl (struct function *fun, tree d)
+{
+  VEC_safe_push (tree, gc, fun->local_decls, d);
+}
+
+#define FOR_EACH_LOCAL_DECL(FUN, I, D)		\
+  FOR_EACH_VEC_ELT_REVERSE (tree, (FUN)->local_decls, I, D)
+
 /* If va_list_[gf]pr_size is set to this, it means we don't know how
    many units need to be saved.  */
 #define VA_LIST_MAX_GPR_SIZE	255
diff --git a/gcc/gimple-low.c b/gcc/gimple-low.c
index 0823b89..381068a 100644
--- a/gcc/gimple-low.c
+++ b/gcc/gimple-low.c
@@ -907,8 +907,7 @@ record_vars_into (tree vars, tree fn)
 	continue;
 
       /* Record the variable.  */
-      cfun->local_decls = tree_cons (NULL_TREE, var,
-					     cfun->local_decls);
+      add_local_decl (cfun, var);
     }
 
   if (fn != current_function_decl)
diff --git a/gcc/ipa-struct-reorg.c b/gcc/ipa-struct-reorg.c
index 98ad91f..4ee8e02 100644
--- a/gcc/ipa-struct-reorg.c
+++ b/gcc/ipa-struct-reorg.c
@@ -3418,7 +3418,6 @@ static void
 build_data_structure (VEC (tree, heap) **unsuitable_types)
 {
   tree var, type;
-  tree var_list;
   struct varpool_node *current_varpool;
   struct cgraph_node *c_node;
 
@@ -3441,6 +3440,7 @@ build_data_structure (VEC (tree, heap) **unsuitable_types)
       if (avail == AVAIL_LOCAL || avail == AVAIL_AVAILABLE)
 	{
 	  struct function *fn = DECL_STRUCT_FUNCTION (c_node->decl);
+	  unsigned ix;
 
 	  for (var = DECL_ARGUMENTS (c_node->decl); var;
 	       var = TREE_CHAIN (var))
@@ -3456,14 +3456,9 @@ build_data_structure (VEC (tree, heap) **unsuitable_types)
 	    }
 
 	  /* Check function local variables.  */
-	  for (var_list = fn->local_decls; var_list;
-	       var_list = TREE_CHAIN (var_list))
-	    {
-	      var = TREE_VALUE (var_list);
-
-	      if (is_candidate (var, &type, unsuitable_types))
-		add_structure (type);
-	    }
+	  FOR_EACH_LOCAL_DECL (fn, ix, var)
+	    if (is_candidate (var, &type, unsuitable_types))
+	      add_structure (type);
 	}
     }
 }
diff --git a/gcc/ipa-type-escape.c b/gcc/ipa-type-escape.c
index b6744a6..3b395f9 100644
--- a/gcc/ipa-type-escape.c
+++ b/gcc/ipa-type-escape.c
@@ -1676,12 +1676,11 @@ analyze_function (struct cgraph_node *fn)
   /* There may be const decls with interesting right hand sides.  */
   if (DECL_STRUCT_FUNCTION (decl))
     {
-      tree step;
-      for (step = DECL_STRUCT_FUNCTION (decl)->local_decls;
-	   step;
-	   step = TREE_CHAIN (step))
+      tree var;
+      unsigned ix;
+
+      FOR_EACH_LOCAL_DECL (DECL_STRUCT_FUNCTION (decl), ix, var)
 	{
-	  tree var = TREE_VALUE (step);
 	  if (TREE_CODE (var) == VAR_DECL
 	      && DECL_INITIAL (var)
 	      && !TREE_STATIC (var))
diff --git a/gcc/lto-streamer-in.c b/gcc/lto-streamer-in.c
index 635cff4..47f40e2 100644
--- a/gcc/lto-streamer-in.c
+++ b/gcc/lto-streamer-in.c
@@ -1286,6 +1286,7 @@ input_function (tree fn_decl, struct data_in *data_in,
   struct bitpack_d bp;
   struct cgraph_node *node;
   tree args, narg, oarg;
+  int len;
 
   fn = DECL_STRUCT_FUNCTION (fn_decl);
   tag = input_record_start (ib);
@@ -1320,7 +1321,17 @@ input_function (tree fn_decl, struct data_in *data_in,
   fn->nonlocal_goto_save_area = lto_input_tree (ib, data_in);
 
   /* Read all the local symbols.  */
-  fn->local_decls = lto_input_tree (ib, data_in);
+  len = lto_input_sleb128 (ib);
+  if (len > 0)
+    {
+      int i;
+      VEC_safe_grow (tree, gc, fn->local_decls, len);
+      for (i = 0; i < len; i++)
+	{
+	  tree t = lto_input_tree (ib, data_in);
+	  VEC_replace (tree, fn->local_decls, i, t);
+	}
+    }
 
   /* Read all function arguments.  We need to re-map them here to the
      arguments of the merged function declaration.  */
diff --git a/gcc/lto-streamer-out.c b/gcc/lto-streamer-out.c
index d4bccfb..b702951 100644
--- a/gcc/lto-streamer-out.c
+++ b/gcc/lto-streamer-out.c
@@ -1840,6 +1840,8 @@ output_function (struct cgraph_node *node)
   struct function *fn;
   basic_block bb;
   struct output_block *ob;
+  unsigned i;
+  tree t;
 
   function = node->decl;
   fn = DECL_STRUCT_FUNCTION (function);
@@ -1886,7 +1888,9 @@ output_function (struct cgraph_node *node)
   lto_output_tree_ref (ob, fn->nonlocal_goto_save_area);
 
   /* Output all the local variables in the function.  */
-  lto_output_tree_ref (ob, fn->local_decls);
+  output_sleb128 (ob, VEC_length (tree, fn->local_decls));
+  for (i = 0; VEC_iterate (tree, fn->local_decls, i, t); i++)
+    lto_output_tree_ref (ob, t);
 
   /* Output the head of the arguments list.  */
   lto_output_tree_ref (ob, DECL_ARGUMENTS (function));
diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index eca27c8d..f289159 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -3138,20 +3138,18 @@ maybe_catch_exception (gimple_seq body)
 /* Chain all the DECLs in LIST by their TREE_CHAIN fields.  */
 
 static tree
-list2chain (tree list)
+vec2chain (VEC(tree,gc) *v)
 {
-  tree t;
+  tree chain = NULL_TREE, t;
+  unsigned ix;
 
-  for (t = list; t; t = TREE_CHAIN (t))
+  FOR_EACH_VEC_ELT_REVERSE (tree, v, ix, t)
     {
-      tree var = TREE_VALUE (t);
-      if (TREE_CHAIN (t))
-	TREE_CHAIN (var) = TREE_VALUE (TREE_CHAIN (t));
-      else
-	TREE_CHAIN (var) = NULL_TREE;
+      TREE_CHAIN (t) = chain;
+      chain = t;
     }
 
-  return list ? TREE_VALUE (list) : NULL_TREE;
+  return chain;
 }
 
 
@@ -3210,12 +3208,12 @@ remove_exit_barrier (struct omp_region *region)
 	    {
 	      gimple parallel_stmt = last_stmt (region->entry);
 	      tree child_fun = gimple_omp_parallel_child_fn (parallel_stmt);
-	      tree local_decls = DECL_STRUCT_FUNCTION (child_fun)->local_decls;
-	      tree block;
+	      tree local_decls, block, decl;
+	      unsigned ix;
 
 	      any_addressable_vars = 0;
-	      for (; local_decls; local_decls = TREE_CHAIN (local_decls))
-		if (TREE_ADDRESSABLE (TREE_VALUE (local_decls)))
+	      FOR_EACH_LOCAL_DECL (DECL_STRUCT_FUNCTION (child_fun), ix, decl)
+		if (TREE_ADDRESSABLE (decl))
 		  {
 		    any_addressable_vars = 1;
 		    break;
@@ -3334,7 +3332,7 @@ expand_omp_taskreg (struct omp_region *region)
 {
   basic_block entry_bb, exit_bb, new_bb;
   struct function *child_cfun;
-  tree child_fn, block, t, ws_args, *tp;
+  tree child_fn, block, t, ws_args;
   tree save_current;
   gimple_stmt_iterator gsi;
   gimple entry_stmt, stmt;
@@ -3380,6 +3378,8 @@ expand_omp_taskreg (struct omp_region *region)
     }
   else
     {
+      unsigned ix;
+
       /* If the parallel region needs data sent from the parent
 	 function, then the very first statement (except possible
 	 tree profile counter updates) of the parallel body
@@ -3457,7 +3457,7 @@ expand_omp_taskreg (struct omp_region *region)
 
       /* Declare local variables needed in CHILD_CFUN.  */
       block = DECL_INITIAL (child_fn);
-      BLOCK_VARS (block) = list2chain (child_cfun->local_decls);
+      BLOCK_VARS (block) = vec2chain (child_cfun->local_decls);
       /* The gimplifier could record temporaries in parallel/task block
 	 rather than in containing function's local_decls chain,
 	 which would mean cgraph missed finalizing them.  Do it now.  */
@@ -3515,11 +3515,11 @@ expand_omp_taskreg (struct omp_region *region)
 	single_succ_edge (new_bb)->flags = EDGE_FALLTHRU;
 
       /* Remove non-local VAR_DECLs from child_cfun->local_decls list.  */
-      for (tp = &child_cfun->local_decls; *tp; )
-	if (DECL_CONTEXT (TREE_VALUE (*tp)) != cfun->decl)
-	  tp = &TREE_CHAIN (*tp);
+      for (ix = 0; VEC_iterate (tree, child_cfun->local_decls, ix, t); )
+	if (DECL_CONTEXT (t) != cfun->decl)
+	  ix++;
 	else
-	  *tp = TREE_CHAIN (*tp);
+	  VEC_unordered_remove (tree, child_cfun->local_decls, ix);
 
       /* Inform the callgraph about the new function.  */
       DECL_STRUCT_FUNCTION (child_fn)->curr_properties
diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index ccafa4d..87603e7 100644
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -5596,7 +5596,7 @@ replace_by_duplicate_decl (tree *tp, struct pointer_map_t *vars_map,
       if (SSA_VAR_P (t))
 	{
 	  new_t = copy_var_decl (t, DECL_NAME (t), TREE_TYPE (t));
-	  f->local_decls = tree_cons (NULL_TREE, new_t, f->local_decls);
+	  add_local_decl (f, new_t);
 	}
       else
 	{
@@ -6316,7 +6316,7 @@ move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
 void
 dump_function_to_file (tree fn, FILE *file, int flags)
 {
-  tree arg, vars, var;
+  tree arg, var;
   struct function *dsf;
   bool ignore_topmost_bind = false, any_var = false;
   basic_block bb;
@@ -6356,15 +6356,14 @@ dump_function_to_file (tree fn, FILE *file, int flags)
 
   /* When GIMPLE is lowered, the variables are no longer available in
      BIND_EXPRs, so display them separately.  */
-  if (cfun && cfun->decl == fn && cfun->local_decls)
+  if (cfun && cfun->decl == fn && !VEC_empty (tree, cfun->local_decls))
     {
+      unsigned ix;
       ignore_topmost_bind = true;
 
       fprintf (file, "{\n");
-      for (vars = cfun->local_decls; vars; vars = TREE_CHAIN (vars))
+      FOR_EACH_LOCAL_DECL (cfun, ix, var)
 	{
-	  var = TREE_VALUE (vars);
-
 	  print_generic_decl (file, var, flags);
 	  if (flags & TDF_VERBOSE)
 	    print_node (file, "", var, 4);
diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c
index 46c604f..e295a6a 100644
--- a/gcc/tree-inline.c
+++ b/gcc/tree-inline.c
@@ -545,8 +545,7 @@ remap_decls (tree decls, VEC(tree,gc) **nonlocalized_list, copy_body_data *id)
 	  if (TREE_CODE (old_var) == VAR_DECL
 	      && ! DECL_EXTERNAL (old_var)
 	      && (var_ann (old_var) || !gimple_in_ssa_p (cfun)))
-	    cfun->local_decls = tree_cons (NULL_TREE, old_var,
-						   cfun->local_decls);
+	    add_local_decl (cfun, old_var);
 	  if ((!optimize || debug_info_level > DINFO_LEVEL_TERSE)
 	      && !DECL_IGNORED_P (old_var)
 	      && nonlocalized_list)
@@ -2854,9 +2853,7 @@ declare_return_variable (copy_body_data *id, tree return_slot, tree modify_dest)
     }
 
   DECL_SEEN_IN_BIND_EXPR_P (var) = 1;
-  DECL_STRUCT_FUNCTION (caller)->local_decls
-    = tree_cons (NULL_TREE, var,
-		 DECL_STRUCT_FUNCTION (caller)->local_decls);
+  add_local_decl (DECL_STRUCT_FUNCTION (caller), var);
 
   /* Do not have the rest of GCC warn about this variable as it should
      not be visible to the user.  */
@@ -2915,7 +2912,8 @@ static const char *
 copy_forbidden (struct function *fun, tree fndecl)
 {
   const char *reason = fun->cannot_be_copied_reason;
-  tree step;
+  tree decl;
+  unsigned ix;
 
   /* Only examine the function once.  */
   if (fun->cannot_be_copied_set)
@@ -2934,23 +2932,19 @@ copy_forbidden (struct function *fun, tree fndecl)
       goto fail;
     }
 
-  for (step = fun->local_decls; step; step = TREE_CHAIN (step))
-    {
-      tree decl = TREE_VALUE (step);
-
-      if (TREE_CODE (decl) == VAR_DECL
-	  && TREE_STATIC (decl)
-	  && !DECL_EXTERNAL (decl)
-	  && DECL_INITIAL (decl)
-	  && walk_tree_without_duplicates (&DECL_INITIAL (decl),
-					   has_label_address_in_static_1,
-					   fndecl))
-	{
-	  reason = G_("function %q+F can never be copied because it saves "
-		      "address of local label in a static variable");
-	  goto fail;
-	}
-    }
+  FOR_EACH_LOCAL_DECL (fun, ix, decl)
+    if (TREE_CODE (decl) == VAR_DECL
+	&& TREE_STATIC (decl)
+	&& !DECL_EXTERNAL (decl)
+	&& DECL_INITIAL (decl)
+	&& walk_tree_without_duplicates (&DECL_INITIAL (decl),
+					 has_label_address_in_static_1,
+					 fndecl))
+      {
+	reason = G_("function %q+F can never be copied because it saves "
+		    "address of local label in a static variable");
+	goto fail;
+      }
 
  fail:
   fun->cannot_be_copied_reason = reason;
@@ -3737,6 +3731,26 @@ prepend_lexical_block (tree current_block, tree new_block)
   BLOCK_SUPERCONTEXT (new_block) = current_block;
 }
 
+/* Add local variables from CALLEE to CALLER.  */
+
+static inline void
+add_local_variables (struct function *callee, struct function *caller,
+		     copy_body_data *id, bool check_var_ann)
+{
+  tree var;
+  unsigned ix;
+
+  FOR_EACH_LOCAL_DECL (callee, ix, var)
+    if (TREE_STATIC (var) && !TREE_ASM_WRITTEN (var))
+      {
+	if (!check_var_ann
+	    || (var_ann (var) && add_referenced_var (var)))
+	  add_local_decl (caller, var);
+      }
+    else if (!can_be_nonlocal (var, id))
+      add_local_decl (caller, remap_decl (var, id));
+}
+
 /* Fetch callee declaration from the call graph edge going from NODE and
    associated with STMR call statement.  Return NULL_TREE if not found.  */
 static tree
@@ -3769,8 +3783,6 @@ expand_call_inline (basic_block bb, gimple stmt, copy_body_data *id)
   gimple_stmt_iterator gsi, stmt_gsi;
   bool successfully_inlined = FALSE;
   bool purge_dead_abnormal_edges;
-  tree t_step;
-  tree var;
 
   /* Set input_location here so we get the right instantiation context
      if we call instantiate_decl from inlinable_function_p.  */
@@ -3974,20 +3986,7 @@ expand_call_inline (basic_block bb, gimple stmt, copy_body_data *id)
   use_retvar = declare_return_variable (id, return_slot, modify_dest);
 
   /* Add local vars in this inlined callee to caller.  */
-  t_step = id->src_cfun->local_decls;
-  for (; t_step; t_step = TREE_CHAIN (t_step))
-    {
-      var = TREE_VALUE (t_step);
-      if (TREE_STATIC (var) && !TREE_ASM_WRITTEN (var))
-	{
-	  if (var_ann (var) && add_referenced_var (var))
-	    cfun->local_decls = tree_cons (NULL_TREE, var,
-					   cfun->local_decls);
-	}
-      else if (!can_be_nonlocal (var, id))
-	cfun->local_decls = tree_cons (NULL_TREE, remap_decl (var, id),
-				       cfun->local_decls);
-    }
+  add_local_variables (id->src_cfun, cfun, id, true);
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
@@ -4729,7 +4728,7 @@ declare_inline_vars (tree block, tree vars)
     {
       DECL_SEEN_IN_BIND_EXPR_P (t) = 1;
       gcc_assert (!TREE_STATIC (t) && !TREE_ASM_WRITTEN (t));
-      cfun->local_decls = tree_cons (NULL_TREE, t, cfun->local_decls);
+      add_local_decl (cfun, t);
     }
 
   if (block)
@@ -5060,7 +5059,6 @@ tree_function_versioning (tree old_decl, tree new_decl,
   basic_block old_entry_block, bb;
   VEC (gimple, heap) *init_stmts = VEC_alloc (gimple, heap, 10);
 
-  tree t_step;
   tree old_current_function_decl = current_function_decl;
   tree vars = NULL_TREE;
 
@@ -5185,19 +5183,9 @@ tree_function_versioning (tree old_decl, tree new_decl,
 
   declare_inline_vars (DECL_INITIAL (new_decl), vars);
 
-  if (DECL_STRUCT_FUNCTION (old_decl)->local_decls != NULL_TREE)
+  if (!VEC_empty (tree, DECL_STRUCT_FUNCTION (old_decl)->local_decls))
     /* Add local vars.  */
-    for (t_step = DECL_STRUCT_FUNCTION (old_decl)->local_decls;
-	 t_step; t_step = TREE_CHAIN (t_step))
-      {
-	tree var = TREE_VALUE (t_step);
-	if (TREE_STATIC (var) && !TREE_ASM_WRITTEN (var))
-	  cfun->local_decls = tree_cons (NULL_TREE, var, cfun->local_decls);
-	else if (!can_be_nonlocal (var, &id))
-	  cfun->local_decls =
-	    tree_cons (NULL_TREE, remap_decl (var, &id),
-		       cfun->local_decls);
-      }
+    add_local_variables (DECL_STRUCT_FUNCTION (old_decl), cfun, &id, false);
 
   /* Copy the Function's body.  */
   copy_body (&id, old_entry_block->count, REG_BR_PROB_BASE,
diff --git a/gcc/tree-ssa-live.c b/gcc/tree-ssa-live.c
index ca1b985..045d42c 100644
--- a/gcc/tree-ssa-live.c
+++ b/gcc/tree-ssa-live.c
@@ -663,10 +663,11 @@ void
 remove_unused_locals (void)
 {
   basic_block bb;
-  tree t, *cell;
+  tree var, t;
   referenced_var_iterator rvi;
   var_ann_t ann;
   bitmap global_unused_vars = NULL;
+  unsigned ix;
 
   /* Removing declarations from lexical blocks when not optimizing is
      not only a waste of time, it actually causes differences in stack
@@ -733,10 +734,8 @@ remove_unused_locals (void)
   cfun->has_local_explicit_reg_vars = false;
 
   /* Remove unmarked local vars from local_decls.  */
-  for (cell = &cfun->local_decls; *cell; )
+  for (ix = 0; VEC_iterate (tree, cfun->local_decls, ix, var); )
     {
-      tree var = TREE_VALUE (*cell);
-
       if (TREE_CODE (var) != FUNCTION_DECL
 	  && (!(ann = var_ann (var))
 	      || !ann->used))
@@ -749,7 +748,7 @@ remove_unused_locals (void)
 	    }
 	  else
 	    {
-	      *cell = TREE_CHAIN (*cell);
+	      VEC_unordered_remove (tree, cfun->local_decls, ix);
 	      continue;
 	    }
 	}
@@ -757,34 +756,29 @@ remove_unused_locals (void)
 	       && DECL_HARD_REGISTER (var)
 	       && !is_global_var (var))
 	cfun->has_local_explicit_reg_vars = true;
-      cell = &TREE_CHAIN (*cell);
+
+      ix++;
     }
 
   /* Remove unmarked global vars from local_decls.  */
   if (global_unused_vars != NULL)
     {
-      for (t = cfun->local_decls; t; t = TREE_CHAIN (t))
-	{
-	  tree var = TREE_VALUE (t);
-
-	  if (TREE_CODE (var) == VAR_DECL
-	      && is_global_var (var)
-	      && (ann = var_ann (var)) != NULL
-	      && ann->used)
-	    mark_all_vars_used (&DECL_INITIAL (var), global_unused_vars);
-	}
-
-      for (cell = &cfun->local_decls; *cell; )
-	{
-	  tree var = TREE_VALUE (*cell);
-
-	  if (TREE_CODE (var) == VAR_DECL
-	      && is_global_var (var)
-	      && bitmap_bit_p (global_unused_vars, DECL_UID (var)))
-	    *cell = TREE_CHAIN (*cell);
-	  else
-	    cell = &TREE_CHAIN (*cell);
-	}
+      tree var;
+      unsigned ix;
+      FOR_EACH_LOCAL_DECL (cfun, ix, var)
+	if (TREE_CODE (var) == VAR_DECL
+	    && is_global_var (var)
+	    && (ann = var_ann (var)) != NULL
+	    && ann->used)
+	  mark_all_vars_used (&DECL_INITIAL (var), global_unused_vars);
+
+      for (ix = 0; VEC_iterate (tree, cfun->local_decls, ix, var); )
+	if (TREE_CODE (var) == VAR_DECL
+	    && is_global_var (var)
+	    && bitmap_bit_p (global_unused_vars, DECL_UID (var)))
+	  VEC_unordered_remove (tree, cfun->local_decls, ix);
+	else
+	  ix++;
       BITMAP_FREE (global_unused_vars);
     }
 
diff --git a/gcc/tree.c b/gcc/tree.c
index b5a99f9..4247047 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -4498,6 +4498,7 @@ free_lang_data_in_decl (tree decl)
       if (gimple_has_body_p (decl))
 	{
 	  tree t;
+	  unsigned ix;
 	  struct pointer_set_t *locals;
 
 	  /* If DECL has a gimple body, then the context for its
@@ -4514,14 +4515,13 @@ free_lang_data_in_decl (tree decl)
 
 	  /* Collect all the symbols declared in DECL.  */
 	  locals = pointer_set_create ();
-	  t = DECL_STRUCT_FUNCTION (decl)->local_decls;
-	  for (; t; t = TREE_CHAIN (t))
+	  FOR_EACH_LOCAL_DECL (DECL_STRUCT_FUNCTION (decl), ix, t)
 	    {
-	      pointer_set_insert (locals, TREE_VALUE (t));
+	      pointer_set_insert (locals, t);
 
 	      /* All the local symbols should have DECL as their
 		 context.  */
-	      DECL_CONTEXT (TREE_VALUE (t)) = decl;
+	      DECL_CONTEXT (t) = decl;
 	    }
 
 	  /* Get rid of any decl not in local_decls.  */
@@ -4873,6 +4873,7 @@ find_decls_types_in_node (struct cgraph_node *n, struct free_lang_data_d *fld)
 {
   basic_block bb;
   struct function *fn;
+  unsigned ix;
   tree t;
 
   find_decls_types (n->decl, fld);
@@ -4885,8 +4886,8 @@ find_decls_types_in_node (struct cgraph_node *n, struct free_lang_data_d *fld)
   fn = DECL_STRUCT_FUNCTION (n->decl);
 
   /* Traverse locals. */
-  for (t = fn->local_decls; t; t = TREE_CHAIN (t))
-    find_decls_types (TREE_VALUE (t), fld);
+  FOR_EACH_LOCAL_DECL (fn, ix, t)
+    find_decls_types (t, fld);
 
   /* Traverse EH regions in FN.  */
   {
diff --git a/gcc/vec.h b/gcc/vec.h
index e6c42bc..a652250 100644
--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -190,6 +190,13 @@ along with GCC; see the file COPYING3.  If not see
 
 #define VEC_iterate(T,V,I,P)	(VEC_OP(T,base,iterate)(VEC_BASE(V),I,&(P)))
 
+/* Convenience macro for reverse iteration.  */
+
+#define FOR_EACH_VEC_ELT_REVERSE(T,V,I,P) \
+  for (I = VEC_length (T, (V)) - 1;           \
+       VEC_iterate (T, (V), (I), (P));	  \
+       (I)--)
+
 /* Allocate new vector.
    VEC(T,A) *VEC_T_A_alloc(int reserve);