OSDN Git Service

PR/51443
[pf3gnuchains/gcc-fork.git] / gcc / ipa-pure-const.c
index 1aef09f..82e24cf 100644 (file)
@@ -1,5 +1,6 @@
 /* Callgraph based analysis of static variables.
-   Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
+   Copyright (C) 2004, 2005, 2007, 2008, 2009, 2010
+   Free Software Foundation, Inc.
    Contributed by Kenneth Zadeck <zadeck@naturalbridge.com>
 
 This file is part of GCC.
@@ -43,15 +44,22 @@ along with GCC; see the file COPYING3.  If not see
 #include "pointer-set.h"
 #include "ggc.h"
 #include "ipa-utils.h"
-#include "c-common.h"
 #include "gimple.h"
 #include "cgraph.h"
 #include "output.h"
 #include "flags.h"
 #include "timevar.h"
 #include "diagnostic.h"
+#include "gimple-pretty-print.h"
 #include "langhooks.h"
 #include "target.h"
+#include "lto-streamer.h"
+#include "data-streamer.h"
+#include "tree-streamer.h"
+#include "cfgloop.h"
+#include "tree-scalar-evolution.h"
+#include "intl.h"
+#include "opts.h"
 
 static struct pointer_set_t *visited_nodes;
 
@@ -65,14 +73,17 @@ enum pure_const_state_e
   IPA_NEITHER
 };
 
+const char *pure_const_names[3] = {"const", "pure", "neither"};
+
 /* Holder for the const_state.  There is one of these per function
    decl.  */
-struct funct_state_d 
+struct funct_state_d
 {
   /* See above.  */
   enum pure_const_state_e pure_const_state;
   /* What user set here; we can be always sure about this.  */
-  enum pure_const_state_e state_set_in_source; 
+  enum pure_const_state_e state_previously_known;
+  bool looping_previously_known;
 
   /* True if the function could possibly infinite loop.  There are a
      lot of ways that this could be determined.  We are pretty
@@ -85,11 +96,16 @@ struct funct_state_d
   bool can_throw;
 };
 
+/* State used when we know nothing about function.  */
+static struct funct_state_d varying_state
+   = { IPA_NEITHER, IPA_NEITHER, true, true, true };
+
+
 typedef struct funct_state_d * funct_state;
 
 /* The storage of the funct_state is abstracted because there is the
    possibility that it may be desirable to move this to the cgraph
-   local info.  */ 
+   local info.  */
 
 /* Array, indexed by cgraph node uid, of function states.  */
 
@@ -102,6 +118,81 @@ static struct cgraph_node_hook_list *function_insertion_hook_holder;
 static struct cgraph_2node_hook_list *node_duplication_hook_holder;
 static struct cgraph_node_hook_list *node_removal_hook_holder;
 
+/* Try to guess if function body will always be visible to compiler
+   when compiling the call and whether compiler will be able
+   to propagate the information by itself.  */
+
+static bool
+function_always_visible_to_compiler_p (tree decl)
+{
+  return (!TREE_PUBLIC (decl) || DECL_DECLARED_INLINE_P (decl));
+}
+
+/* Emit suggestion about attribute ATTRIB_NAME for DECL.  KNOWN_FINITE
+   is true if the function is known to be finite.  The diagnostic is
+   controlled by OPTION.  WARNED_ABOUT is a pointer_set unique for
+   OPTION, this function may initialize it and it is always returned
+   by the function.  */
+
+static struct pointer_set_t *
+suggest_attribute (int option, tree decl, bool known_finite,
+                  struct pointer_set_t *warned_about,
+                  const char * attrib_name)
+{
+  if (!option_enabled (option, &global_options))
+    return warned_about;
+  if (TREE_THIS_VOLATILE (decl)
+      || (known_finite && function_always_visible_to_compiler_p (decl)))
+    return warned_about;
+
+  if (!warned_about)
+    warned_about = pointer_set_create (); 
+  if (pointer_set_contains (warned_about, decl))
+    return warned_about;
+  pointer_set_insert (warned_about, decl);
+  warning_at (DECL_SOURCE_LOCATION (decl),
+             option,
+             known_finite
+             ? _("function might be candidate for attribute %<%s%>")
+             : _("function might be candidate for attribute %<%s%>"
+                 " if it is known to return normally"), attrib_name);
+  return warned_about;
+}
+
+/* Emit suggestion about __attribute_((pure)) for DECL.  KNOWN_FINITE
+   is true if the function is known to be finite.  */
+
+static void
+warn_function_pure (tree decl, bool known_finite)
+{
+  static struct pointer_set_t *warned_about;
+
+  warned_about 
+    = suggest_attribute (OPT_Wsuggest_attribute_pure, decl,
+                        known_finite, warned_about, "pure");
+}
+
+/* Emit suggestion about __attribute_((const)) for DECL.  KNOWN_FINITE
+   is true if the function is known to be finite.  */
+
+static void
+warn_function_const (tree decl, bool known_finite)
+{
+  static struct pointer_set_t *warned_about;
+  warned_about 
+    = suggest_attribute (OPT_Wsuggest_attribute_const, decl,
+                        known_finite, warned_about, "const");
+}
+
+void
+warn_function_noreturn (tree decl)
+{
+  static struct pointer_set_t *warned_about;
+  if (!lang_hooks.missing_noreturn_ok_p (decl))
+    warned_about 
+      = suggest_attribute (OPT_Wsuggest_attribute_noreturn, decl,
+                          true, warned_about, "noreturn");
+}
 /* Init the function state.  */
 
 static void
@@ -111,15 +202,28 @@ finish_state (void)
 }
 
 
-/* Return the function state from NODE.  */ 
+/* Return true if we have a function state for NODE.  */
+
+static inline bool
+has_function_state (struct cgraph_node *node)
+{
+  if (!funct_state_vec
+      || VEC_length (funct_state, funct_state_vec) <= (unsigned int)node->uid)
+    return false;
+  return VEC_index (funct_state, funct_state_vec, node->uid) != NULL;
+}
+
+/* Return the function state from NODE.  */
 
 static inline funct_state
 get_function_state (struct cgraph_node *node)
 {
   if (!funct_state_vec
-      || VEC_length (funct_state, funct_state_vec) <= (unsigned int)node->uid)
-    return NULL;
-  return VEC_index (funct_state, funct_state_vec, node->uid);
+      || VEC_length (funct_state, funct_state_vec) <= (unsigned int)node->uid
+      || !VEC_index (funct_state, funct_state_vec, node->uid))
+    /* We might want to put correct previously_known state into varying.  */
+    return &varying_state;
+ return VEC_index (funct_state, funct_state_vec, node->uid);
 }
 
 /* Set the function state S for NODE.  */
@@ -136,14 +240,14 @@ set_function_state (struct cgraph_node *node, funct_state s)
 /* Check to see if the use (or definition when CHECKING_WRITE is true)
    variable T is legal in a function that is either pure or const.  */
 
-static inline void 
-check_decl (funct_state local, 
-           tree t, bool checking_write)
+static inline void
+check_decl (funct_state local,
+           tree t, bool checking_write, bool ipa)
 {
   /* Do not want to do anything with volatile except mark any
      function that uses one to be not const or pure.  */
-  if (TREE_THIS_VOLATILE (t)) 
-    { 
+  if (TREE_THIS_VOLATILE (t))
+    {
       local->pure_const_state = IPA_NEITHER;
       if (dump_file)
         fprintf (dump_file, "    Volatile operand is not const/pure");
@@ -156,7 +260,7 @@ check_decl (funct_state local,
 
   /* If the variable has the "used" attribute, treat it as if it had a
      been touched by the devil.  */
-  if (lookup_attribute ("used", DECL_ATTRIBUTES (t)))
+  if (DECL_PRESERVE_P (t))
     {
       local->pure_const_state = IPA_NEITHER;
       if (dump_file)
@@ -164,10 +268,15 @@ check_decl (funct_state local,
       return;
     }
 
+  /* In IPA mode we are not interested in checking actual loads and stores;
+     they will be processed at propagation time using ipa_ref.  */
+  if (ipa)
+    return;
+
   /* Since we have dealt with the locals and params cases above, if we
      are CHECKING_WRITE, this cannot be a pure or constant
      function.  */
-  if (checking_write) 
+  if (checking_write)
     {
       local->pure_const_state = IPA_NEITHER;
       if (dump_file)
@@ -180,7 +289,7 @@ check_decl (funct_state local,
       /* Readonly reads are safe.  */
       if (TREE_READONLY (t) && !TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (t)))
        return; /* Read of a constant, do not change the function state.  */
-      else 
+      else
        {
           if (dump_file)
             fprintf (dump_file, "    global memory read is not const\n");
@@ -208,16 +317,26 @@ check_decl (funct_state local,
 /* Check to see if the use (or definition when CHECKING_WRITE is true)
    variable T is legal in a function that is either pure or const.  */
 
-static inline void 
+static inline void
 check_op (funct_state local, tree t, bool checking_write)
 {
-  if (TREE_THIS_VOLATILE (t))
+  t = get_base_address (t);
+  if (t && TREE_THIS_VOLATILE (t))
     {
       local->pure_const_state = IPA_NEITHER;
       if (dump_file)
        fprintf (dump_file, "    Volatile indirect ref is not const/pure\n");
       return;
     }
+  else if (t
+          && (INDIRECT_REF_P (t) || TREE_CODE (t) == MEM_REF)
+          && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
+          && !ptr_deref_may_alias_global_p (TREE_OPERAND (t, 0)))
+    {
+      if (dump_file)
+       fprintf (dump_file, "    Indirect ref to local memory is OK\n");
+      return;
+    }
   else if (checking_write)
     {
       local->pure_const_state = IPA_NEITHER;
@@ -234,6 +353,112 @@ check_op (funct_state local, tree t, bool checking_write)
     }
 }
 
+/* compute state based on ECF FLAGS and store to STATE and LOOPING.  */
+
+static void
+state_from_flags (enum pure_const_state_e *state, bool *looping,
+                 int flags, bool cannot_lead_to_return)
+{
+  *looping = false;
+  if (flags & ECF_LOOPING_CONST_OR_PURE)
+    {
+      *looping = true;
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf (dump_file, " looping");
+    }
+  if (flags & ECF_CONST)
+    {
+      *state = IPA_CONST;
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf (dump_file, " const\n");
+    }
+  else if (flags & ECF_PURE)
+    {
+      *state = IPA_PURE;
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf (dump_file, " pure\n");
+    }
+  else if (cannot_lead_to_return)
+    {
+      *state = IPA_PURE;
+      *looping = true;
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf (dump_file, " ignoring side effects->pure looping\n");
+    }
+  else
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf (dump_file, " neihter\n");
+      *state = IPA_NEITHER;
+      *looping = true;
+    }
+}
+
+/* Merge STATE and STATE2 and LOOPING and LOOPING2 and store
+   into STATE and LOOPING better of the two variants.
+   Be sure to merge looping correctly.  IPA_NEITHER functions
+   have looping 0 even if they don't have to return.  */
+
+static inline void
+better_state (enum pure_const_state_e *state, bool *looping,
+             enum pure_const_state_e state2, bool looping2)
+{
+  if (state2 < *state)
+    {
+      if (*state == IPA_NEITHER)
+       *looping = looping2;
+      else
+       *looping = MIN (*looping, looping2);
+    }
+  else if (state2 != IPA_NEITHER)
+    *looping = MIN (*looping, looping2);
+}
+
+/* Merge STATE and STATE2 and LOOPING and LOOPING2 and store
+   into STATE and LOOPING worse of the two variants.  */
+
+static inline void
+worse_state (enum pure_const_state_e *state, bool *looping,
+            enum pure_const_state_e state2, bool looping2)
+{
+  *state = MAX (*state, state2);
+  *looping = MAX (*looping, looping2);
+}
+
+/* Recognize special cases of builtins that are by themselves not pure or const
+   but function using them is.  */
+static bool
+special_builtin_state (enum pure_const_state_e *state, bool *looping,
+                       tree callee)
+{
+  if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
+    switch (DECL_FUNCTION_CODE (callee))
+      {
+       case BUILT_IN_RETURN:
+       case BUILT_IN_UNREACHABLE:
+       case BUILT_IN_ALLOCA:
+       case BUILT_IN_ALLOCA_WITH_ALIGN:
+       case BUILT_IN_STACK_SAVE:
+       case BUILT_IN_STACK_RESTORE:
+       case BUILT_IN_EH_POINTER:
+       case BUILT_IN_EH_FILTER:
+       case BUILT_IN_UNWIND_RESUME:
+       case BUILT_IN_CXA_END_CLEANUP:
+       case BUILT_IN_EH_COPY_VALUES:
+       case BUILT_IN_FRAME_ADDRESS:
+       case BUILT_IN_APPLY:
+       case BUILT_IN_APPLY_ARGS:
+         *looping = false;
+         *state = IPA_CONST;
+         return true;
+       case BUILT_IN_PREFETCH:
+         *looping = true;
+         *state = IPA_CONST;
+         return true;
+      }
+  return false;
+}
+
 /* Check the parameters of a function call to CALL_EXPR to see if
    there are any references in the parameters that are not allowed for
    pure or const functions.  Also check to see if this is either an
@@ -246,8 +471,6 @@ check_call (funct_state local, gimple call, bool ipa)
 {
   int flags = gimple_call_flags (call);
   tree callee_t = gimple_call_fndecl (call);
-  struct cgraph_node* callee;
-  enum availability avail = AVAIL_NOT_AVAILABLE;
   bool possibly_throws = stmt_could_throw_p (call);
   bool possibly_throws_externally = (possibly_throws
                                     && stmt_can_throw_external (call));
@@ -259,7 +482,7 @@ check_call (funct_state local, gimple call, bool ipa)
         if (gimple_op (call, i)
            && tree_could_throw_p (gimple_op (call, i)))
          {
-           if (possibly_throws && flag_non_call_exceptions)
+           if (possibly_throws && cfun->can_throw_non_call_exceptions)
              {
                if (dump_file)
                  fprintf (dump_file, "    operand can throw; looping\n");
@@ -273,22 +496,28 @@ check_call (funct_state local, gimple call, bool ipa)
              }
          }
     }
-  
+
   /* The const and pure flags are set by a variety of places in the
      compiler (including here).  If someone has already set the flags
      for the callee, (such as for some of the builtins) we will use
-     them, otherwise we will compute our own information. 
-  
+     them, otherwise we will compute our own information.
+
      Const and pure functions have less clobber effects than other
      functions so we process these first.  Otherwise if it is a call
      outside the compilation unit or an indirect call we punt.  This
      leaves local calls which will be processed by following the call
-     graph.  */  
+     graph.  */
   if (callee_t)
     {
-      callee = cgraph_node(callee_t);
-      avail = cgraph_function_body_availability (callee);
+      enum pure_const_state_e call_state;
+      bool call_looping;
 
+      if (special_builtin_state (&call_state, &call_looping, callee_t))
+       {
+         worse_state (&local->pure_const_state, &local->looping,
+                      call_state, call_looping);
+         return;
+       }
       /* When bad things happen to bad functions, they cannot be const
         or pure.  */
       if (setjmp_call_p (callee_t))
@@ -316,15 +545,20 @@ check_call (funct_state local, gimple call, bool ipa)
 
   /* When not in IPA mode, we can still handle self recursion.  */
   if (!ipa && callee_t == current_function_decl)
-    local->looping = true;
-  /* The callee is either unknown (indirect call) or there is just no
-     scannable code for it (external call) .  We look to see if there
-     are any bits available for the callee (such as by declaration or
-     because it is builtin) and process solely on the basis of those
-     bits. */
-  else if (avail <= AVAIL_OVERWRITABLE || !ipa)
-    {
-      if (possibly_throws && flag_non_call_exceptions)
+    {
+      if (dump_file)
+        fprintf (dump_file, "    Recursive call can loop.\n");
+      local->looping = true;
+    }
+  /* Either callee is unknown or we are doing local analysis.
+     Look to see if there are any bits available for the callee (such as by
+     declaration or because it is builtin) and process solely on the basis of
+     those bits. */
+  else if (!ipa)
+    {
+      enum pure_const_state_e call_state;
+      bool call_looping;
+      if (possibly_throws && cfun->can_throw_non_call_exceptions)
         {
          if (dump_file)
            fprintf (dump_file, "    can throw; looping\n");
@@ -334,58 +568,69 @@ check_call (funct_state local, gimple call, bool ipa)
         {
          if (dump_file)
            {
-             fprintf (dump_file, "    can throw externally in region %i\n",
-                      lookup_stmt_eh_region (call));
+             fprintf (dump_file, "    can throw externally to lp %i\n",
+                      lookup_stmt_eh_lp (call));
              if (callee_t)
                fprintf (dump_file, "     callee:%s\n",
                         IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (callee_t)));
            }
           local->can_throw = true;
        }
-      if (flags & ECF_CONST) 
-       {
-          if (callee_t && DECL_LOOPING_CONST_OR_PURE_P (callee_t))
-            local->looping = true;
-        }
-      else if (flags & ECF_PURE) 
-       {
-          if (callee_t && DECL_LOOPING_CONST_OR_PURE_P (callee_t))
-            local->looping = true;
-         if (dump_file)
-           fprintf (dump_file, "    pure function call in not const\n");
-         if (local->pure_const_state == IPA_CONST)
-           local->pure_const_state = IPA_PURE;
-       }
-      else 
-       {
-         if (dump_file)
-           fprintf (dump_file, "    uknown function call is not const/pure\n");
-         local->pure_const_state = IPA_NEITHER;
-          local->looping = true;
-       }
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf (dump_file, "    checking flags for call:");
+      state_from_flags (&call_state, &call_looping, flags,
+                       ((flags & (ECF_NORETURN | ECF_NOTHROW))
+                        == (ECF_NORETURN | ECF_NOTHROW))
+                       || (!flag_exceptions && (flags & ECF_NORETURN)));
+      worse_state (&local->pure_const_state, &local->looping,
+                  call_state, call_looping);
     }
   /* Direct functions calls are handled by IPA propagation.  */
 }
 
-/* Wrapper around check_decl for loads.  */
+/* Wrapper around check_decl for loads in local more.  */
 
 static bool
 check_load (gimple stmt ATTRIBUTE_UNUSED, tree op, void *data)
 {
   if (DECL_P (op))
-    check_decl ((funct_state)data, op, false);
+    check_decl ((funct_state)data, op, false, false);
   else
     check_op ((funct_state)data, op, false);
   return false;
 }
 
-/* Wrapper around check_decl for stores.  */
+/* Wrapper around check_decl for stores in local more.  */
 
 static bool
 check_store (gimple stmt ATTRIBUTE_UNUSED, tree op, void *data)
 {
   if (DECL_P (op))
-    check_decl ((funct_state)data, op, true);
+    check_decl ((funct_state)data, op, true, false);
+  else
+    check_op ((funct_state)data, op, true);
+  return false;
+}
+
+/* Wrapper around check_decl for loads in ipa mode.  */
+
+static bool
+check_ipa_load (gimple stmt ATTRIBUTE_UNUSED, tree op, void *data)
+{
+  if (DECL_P (op))
+    check_decl ((funct_state)data, op, false, true);
+  else
+    check_op ((funct_state)data, op, false);
+  return false;
+}
+
+/* Wrapper around check_decl for stores in ipa mode.  */
+
+static bool
+check_ipa_store (gimple stmt ATTRIBUTE_UNUSED, tree op, void *data)
+{
+  if (DECL_P (op))
+    check_decl ((funct_state)data, op, true, true);
   else
     check_op ((funct_state)data, op, true);
   return false;
@@ -397,7 +642,9 @@ static void
 check_stmt (gimple_stmt_iterator *gsip, funct_state local, bool ipa)
 {
   gimple stmt = gsi_stmt (*gsip);
-  unsigned int i = 0;
+
+  if (is_gimple_debug (stmt))
+    return;
 
   if (dump_file)
     {
@@ -405,13 +652,22 @@ check_stmt (gimple_stmt_iterator *gsip, funct_state local, bool ipa)
       print_gimple_stmt (dump_file, stmt, 0, 0);
     }
 
+  if (gimple_has_volatile_ops (stmt))
+    {
+      local->pure_const_state = IPA_NEITHER;
+      if (dump_file)
+       fprintf (dump_file, "    Volatile stmt is not const/pure\n");
+    }
+
   /* Look for loads and stores.  */
-  walk_stmt_load_store_ops (stmt, local, check_load, check_store);
+  walk_stmt_load_store_ops (stmt, local,
+                           ipa ? check_ipa_load : check_load,
+                           ipa ? check_ipa_store :  check_store);
 
   if (gimple_code (stmt) != GIMPLE_CALL
       && stmt_could_throw_p (stmt))
     {
-      if (flag_non_call_exceptions)
+      if (cfun->can_throw_non_call_exceptions)
        {
          if (dump_file)
            fprintf (dump_file, "    can throw; looping");
@@ -439,16 +695,12 @@ check_stmt (gimple_stmt_iterator *gsip, funct_state local, bool ipa)
        }
       break;
     case GIMPLE_ASM:
-      for (i = 0; i < gimple_asm_nclobbers (stmt); i++)
+      if (gimple_asm_clobbers_memory_p (stmt))
        {
-         tree op = gimple_asm_clobber_op (stmt, i);
-         if (simple_cst_equal(TREE_VALUE (op), memory_identifier_string) == 1) 
-           {
-              if (dump_file)
-                fprintf (dump_file, "    memory asm clobber is not const/pure");
-             /* Abandon all hope, ye who enter here. */
-             local->pure_const_state = IPA_NEITHER;
-           }
+         if (dump_file)
+           fprintf (dump_file, "    memory asm clobber is not const/pure");
+         /* Abandon all hope, ye who enter here. */
+         local->pure_const_state = IPA_NEITHER;
        }
       if (gimple_asm_volatile_p (stmt))
        {
@@ -476,28 +728,32 @@ analyze_function (struct cgraph_node *fn, bool ipa)
   funct_state l;
   basic_block this_block;
 
-  if (cgraph_function_body_availability (fn) <= AVAIL_OVERWRITABLE)
-    {
-      if (dump_file)
-        fprintf (dump_file, "Function is not available or overwrittable; not analyzing.\n");
-      return NULL;
-    }
-
   l = XCNEW (struct funct_state_d);
   l->pure_const_state = IPA_CONST;
-  l->state_set_in_source = IPA_NEITHER;
+  l->state_previously_known = IPA_NEITHER;
+  l->looping_previously_known = true;
   l->looping = false;
   l->can_throw = false;
+  state_from_flags (&l->state_previously_known, &l->looping_previously_known,
+                   flags_from_decl_or_type (fn->decl),
+                   cgraph_node_cannot_return (fn));
+
+  if (fn->thunk.thunk_p || fn->alias)
+    {
+      /* Thunk gets propagated through, so nothing interesting happens.  */
+      gcc_assert (ipa);
+      return l;
+    }
 
   if (dump_file)
     {
-      fprintf (dump_file, "\n\n local analysis of %s\n ", 
+      fprintf (dump_file, "\n\n local analysis of %s\n ",
               cgraph_node_name (fn));
     }
-  
+
   push_cfun (DECL_STRUCT_FUNCTION (decl));
   current_function_decl = decl;
-  
+
   FOR_EACH_BB (this_block)
     {
       gimple_stmt_iterator gsi;
@@ -521,25 +777,45 @@ end:
         indication of possible infinite loop side
         effect.  */
       if (mark_dfs_back_edges ())
-       l->looping = true;
-      
+        {
+         /* Preheaders are needed for SCEV to work.
+            Simple latches and recorded exits improve chances that loop will
+            proved to be finite in testcases such as in loop-15.c and loop-24.c  */
+         loop_optimizer_init (LOOPS_NORMAL
+                              | LOOPS_HAVE_RECORDED_EXITS);
+         if (dump_file && (dump_flags & TDF_DETAILS))
+           flow_loops_dump (dump_file, NULL, 0);
+         if (mark_irreducible_loops ())
+           {
+             if (dump_file)
+               fprintf (dump_file, "    has irreducible loops\n");
+             l->looping = true;
+           }
+         else
+           {
+             loop_iterator li;
+             struct loop *loop;
+             scev_initialize ();
+             FOR_EACH_LOOP (li, loop, 0)
+               if (!finite_loop_p (loop))
+                 {
+                   if (dump_file)
+                     fprintf (dump_file, "    can not prove finiteness of loop %i\n", loop->num);
+                   l->looping =true;
+                   break;
+                 }
+             scev_finalize ();
+           }
+          loop_optimizer_finalize ();
+       }
     }
 
-  if (TREE_READONLY (decl))
-    {
-      l->pure_const_state = IPA_CONST;
-      l->state_set_in_source = IPA_CONST;
-      if (!DECL_LOOPING_CONST_OR_PURE_P (decl))
-        l->looping = false;
-    }
-  if (DECL_PURE_P (decl))
-    {
-      if (l->pure_const_state != IPA_CONST)
-        l->pure_const_state = IPA_PURE;
-      l->state_set_in_source = IPA_PURE;
-      if (!DECL_LOOPING_CONST_OR_PURE_P (decl))
-        l->looping = false;
-    }
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    fprintf (dump_file, "    checking previously known:");
+
+  better_state (&l->pure_const_state, &l->looping,
+               l->state_previously_known,
+               l->looping_previously_known);
   if (TREE_NOTHROW (decl))
     l->can_throw = false;
 
@@ -563,14 +839,15 @@ end:
 static void
 add_new_function (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
 {
- if (cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE)
+ if (cgraph_function_body_availability (node) < AVAIL_OVERWRITABLE)
    return;
   /* There are some shared nodes, in particular the initializers on
      static declarations.  We do not need to scan them more than once
      since all we would be interested in are the addressof
      operations.  */
   visited_nodes = pointer_set_create ();
-  set_function_state (node, analyze_function (node, true));
+  if (cgraph_function_body_availability (node) > AVAIL_OVERWRITABLE)
+    set_function_state (node, analyze_function (node, true));
   pointer_set_destroy (visited_nodes);
   visited_nodes = NULL;
 }
@@ -581,10 +858,10 @@ static void
 duplicate_node_data (struct cgraph_node *src, struct cgraph_node *dst,
                     void *data ATTRIBUTE_UNUSED)
 {
-  if (get_function_state (src))
+  if (has_function_state (src))
     {
       funct_state l = XNEW (struct funct_state_d);
-      gcc_assert (!get_function_state (dst));
+      gcc_assert (!has_function_state (dst));
       memcpy (l, get_function_state (src), sizeof (*l));
       set_function_state (dst, l);
     }
@@ -595,21 +872,25 @@ duplicate_node_data (struct cgraph_node *src, struct cgraph_node *dst,
 static void
 remove_node_data (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
 {
-  if (get_function_state (node))
+  if (has_function_state (node))
     {
-      free (get_function_state (node));
+      funct_state l = get_function_state (node);
+      if (l != &varying_state)
+        free (l);
       set_function_state (node, NULL);
     }
 }
 
 \f
-/* Analyze each function in the cgraph to see if it is locally PURE or
-   CONST.  */
-
-static void 
-generate_summary (void)
+static void
+register_hooks (void)
 {
-  struct cgraph_node *node;
+  static bool init_p = false;
+
+  if (init_p)
+    return;
+
+  init_p = true;
 
   node_removal_hook_holder =
       cgraph_add_node_removal_hook (&remove_node_data, NULL);
@@ -617,39 +898,200 @@ generate_summary (void)
       cgraph_add_node_duplication_hook (&duplicate_node_data, NULL);
   function_insertion_hook_holder =
       cgraph_add_function_insertion_hook (&add_new_function, NULL);
+}
+
+
+/* Analyze each function in the cgraph to see if it is locally PURE or
+   CONST.  */
+
+static void
+generate_summary (void)
+{
+  struct cgraph_node *node;
+
+  register_hooks ();
+
   /* There are some shared nodes, in particular the initializers on
      static declarations.  We do not need to scan them more than once
      since all we would be interested in are the addressof
      operations.  */
   visited_nodes = pointer_set_create ();
 
-  /* Process all of the functions. 
+  /* Process all of the functions.
+
+     We process AVAIL_OVERWRITABLE functions.  We can not use the results
+     by default, but the info can be used at LTO with -fwhole-program or
+     when function got cloned and the clone is AVAILABLE.  */
 
-     We do NOT process any AVAIL_OVERWRITABLE functions, we cannot
-     guarantee that what we learn about the one we see will be true
-     for the one that overrides it.
-  */
   for (node = cgraph_nodes; node; node = node->next)
-    if (cgraph_function_body_availability (node) > AVAIL_OVERWRITABLE)
+    if (cgraph_function_body_availability (node) >= AVAIL_OVERWRITABLE)
       set_function_state (node, analyze_function (node, true));
 
   pointer_set_destroy (visited_nodes);
   visited_nodes = NULL;
 }
 
+
+/* Serialize the ipa info for lto.  */
+
+static void
+pure_const_write_summary (cgraph_node_set set,
+                         varpool_node_set vset ATTRIBUTE_UNUSED)
+{
+  struct cgraph_node *node;
+  struct lto_simple_output_block *ob
+    = lto_create_simple_output_block (LTO_section_ipa_pure_const);
+  unsigned int count = 0;
+  cgraph_node_set_iterator csi;
+
+  for (csi = csi_start (set); !csi_end_p (csi); csi_next (&csi))
+    {
+      node = csi_node (csi);
+      if (node->analyzed && has_function_state (node))
+       count++;
+    }
+
+  streamer_write_uhwi_stream (ob->main_stream, count);
+
+  /* Process all of the functions.  */
+  for (csi = csi_start (set); !csi_end_p (csi); csi_next (&csi))
+    {
+      node = csi_node (csi);
+      if (node->analyzed && has_function_state (node))
+       {
+         struct bitpack_d bp;
+         funct_state fs;
+         int node_ref;
+         lto_cgraph_encoder_t encoder;
+
+         fs = get_function_state (node);
+
+         encoder = ob->decl_state->cgraph_node_encoder;
+         node_ref = lto_cgraph_encoder_encode (encoder, node);
+         streamer_write_uhwi_stream (ob->main_stream, node_ref);
+
+         /* Note that flags will need to be read in the opposite
+            order as we are pushing the bitflags into FLAGS.  */
+         bp = bitpack_create (ob->main_stream);
+         bp_pack_value (&bp, fs->pure_const_state, 2);
+         bp_pack_value (&bp, fs->state_previously_known, 2);
+         bp_pack_value (&bp, fs->looping_previously_known, 1);
+         bp_pack_value (&bp, fs->looping, 1);
+         bp_pack_value (&bp, fs->can_throw, 1);
+         streamer_write_bitpack (&bp);
+       }
+    }
+
+  lto_destroy_simple_output_block (ob);
+}
+
+
+/* Deserialize the ipa info for lto.  */
+
+static void
+pure_const_read_summary (void)
+{
+  struct lto_file_decl_data **file_data_vec = lto_get_file_decl_data ();
+  struct lto_file_decl_data *file_data;
+  unsigned int j = 0;
+
+  register_hooks ();
+  while ((file_data = file_data_vec[j++]))
+    {
+      const char *data;
+      size_t len;
+      struct lto_input_block *ib
+       = lto_create_simple_input_block (file_data,
+                                        LTO_section_ipa_pure_const,
+                                        &data, &len);
+      if (ib)
+       {
+         unsigned int i;
+         unsigned int count = streamer_read_uhwi (ib);
+
+         for (i = 0; i < count; i++)
+           {
+             unsigned int index;
+             struct cgraph_node *node;
+             struct bitpack_d bp;
+             funct_state fs;
+             lto_cgraph_encoder_t encoder;
+
+             fs = XCNEW (struct funct_state_d);
+             index = streamer_read_uhwi (ib);
+             encoder = file_data->cgraph_node_encoder;
+             node = lto_cgraph_encoder_deref (encoder, index);
+             set_function_state (node, fs);
+
+             /* Note that the flags must be read in the opposite
+                order in which they were written (the bitflags were
+                pushed into FLAGS).  */
+             bp = streamer_read_bitpack (ib);
+             fs->pure_const_state
+                       = (enum pure_const_state_e) bp_unpack_value (&bp, 2);
+             fs->state_previously_known
+                       = (enum pure_const_state_e) bp_unpack_value (&bp, 2);
+             fs->looping_previously_known = bp_unpack_value (&bp, 1);
+             fs->looping = bp_unpack_value (&bp, 1);
+             fs->can_throw = bp_unpack_value (&bp, 1);
+             if (dump_file)
+               {
+                 int flags = flags_from_decl_or_type (node->decl);
+                 fprintf (dump_file, "Read info for %s/%i ",
+                          cgraph_node_name (node),
+                          node->uid);
+                 if (flags & ECF_CONST)
+                   fprintf (dump_file, " const");
+                 if (flags & ECF_PURE)
+                   fprintf (dump_file, " pure");
+                 if (flags & ECF_NOTHROW)
+                   fprintf (dump_file, " nothrow");
+                 fprintf (dump_file, "\n  pure const state: %s\n",
+                          pure_const_names[fs->pure_const_state]);
+                 fprintf (dump_file, "  previously known state: %s\n",
+                          pure_const_names[fs->looping_previously_known]);
+                 if (fs->looping)
+                   fprintf (dump_file,"  function is locally looping\n");
+                 if (fs->looping_previously_known)
+                   fprintf (dump_file,"  function is previously known looping\n");
+                 if (fs->can_throw)
+                   fprintf (dump_file,"  function is locally throwing\n");
+               }
+           }
+
+         lto_destroy_simple_input_block (file_data,
+                                         LTO_section_ipa_pure_const,
+                                         ib, data, len);
+       }
+    }
+}
+
+
 static bool
 ignore_edge (struct cgraph_edge *e)
 {
   return (!e->can_throw_external);
 }
 
-/* Produce the global information by preforming a transitive closure
-   on the local information that was produced by generate_summary.
-   Note that there is no function_transform pass since this only
-   updates the function_decl.  */
+/* Return true if NODE is self recursive function.
+   ??? self recursive and indirectly recursive funcions should
+   be the same, so this function seems unnecesary.  */
 
-static unsigned int
-propagate (void)
+static bool
+self_recursive_p (struct cgraph_node *node)
+{
+  struct cgraph_edge *e;
+  for (e = node->callees; e; e = e->next_callee)
+    if (cgraph_function_node (e->callee, NULL) == node)
+      return true;
+  return false;
+}
+
+/* Produce transitive closure over the callgraph and compute pure/const
+   attributes.  */
+
+static void
+propagate_pure_const (void)
 {
   struct cgraph_node *node;
   struct cgraph_node *w;
@@ -659,14 +1101,11 @@ propagate (void)
   int i;
   struct ipa_dfs_info * w_info;
 
-  cgraph_remove_function_insertion_hook (function_insertion_hook_holder);
-  cgraph_remove_node_duplication_hook (node_duplication_hook_holder);
-  cgraph_remove_node_removal_hook (node_removal_hook_holder);
-  order_pos = ipa_utils_reduced_inorder (order, true, false, NULL);
+  order_pos = ipa_reduced_postorder (order, true, false, NULL);
   if (dump_file)
     {
       dump_cgraph (dump_file);
-      ipa_utils_print_order(dump_file, "reduced", order, order_pos);
+      ipa_print_order(dump_file, "reduced", order, order_pos);
     }
 
   /* Propagate the local information thru the call graph to produce
@@ -680,44 +1119,183 @@ propagate (void)
       int count = 0;
       node = order[i];
 
+      if (node->alias)
+       continue;
+
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf (dump_file, "Starting cycle\n");
+
       /* Find the worst state for any node in the cycle.  */
       w = node;
-      while (w)
+      while (w && pure_const_state != IPA_NEITHER)
        {
          struct cgraph_edge *e;
-         funct_state w_l = get_function_state (w);
-         if (pure_const_state < w_l->pure_const_state)
-           pure_const_state = w_l->pure_const_state;
-
-         if (w_l->looping)
-           looping = true;
+         struct cgraph_edge *ie;
+         int i;
+         struct ipa_ref *ref;
 
+         funct_state w_l = get_function_state (w);
+         if (dump_file && (dump_flags & TDF_DETAILS))
+           fprintf (dump_file, "  Visiting %s/%i state:%s looping %i\n",
+                    cgraph_node_name (w),
+                    w->uid,
+                    pure_const_names[w_l->pure_const_state],
+                    w_l->looping);
+
+         /* First merge in function body properties.  */
+         worse_state (&pure_const_state, &looping,
+                      w_l->pure_const_state, w_l->looping);
          if (pure_const_state == IPA_NEITHER)
            break;
 
+         /* For overwritable nodes we can not assume anything.  */
+         if (cgraph_function_body_availability (w) == AVAIL_OVERWRITABLE)
+           {
+             worse_state (&pure_const_state, &looping,
+                          w_l->state_previously_known,
+                          w_l->looping_previously_known);
+             if (dump_file && (dump_flags & TDF_DETAILS))
+               {
+                 fprintf (dump_file,
+                          "    Overwritable. state %s looping %i\n",
+                          pure_const_names[w_l->state_previously_known],
+                          w_l->looping_previously_known);
+               }
+             break;
+           }
+
          count++;
 
+         /* We consider recursive cycles as possibly infinite.
+            This might be relaxed since infinite recursion leads to stack
+            overflow.  */
          if (count > 1)
            looping = true;
-               
-         for (e = w->callees; e; e = e->next_callee) 
+
+         /* Now walk the edges and merge in callee properties.  */
+         for (e = w->callees; e; e = e->next_callee)
            {
-             struct cgraph_node *y = e->callee;
+             enum availability avail;
+             struct cgraph_node *y = cgraph_function_node (e->callee, &avail);
+             enum pure_const_state_e edge_state = IPA_CONST;
+             bool edge_looping = false;
 
-             if (cgraph_function_body_availability (y) > AVAIL_OVERWRITABLE)
+             if (dump_file && (dump_flags & TDF_DETAILS))
+               {
+                 fprintf (dump_file,
+                          "    Call to %s/%i",
+                          cgraph_node_name (e->callee),
+                          e->callee->uid);
+               }
+             if (avail > AVAIL_OVERWRITABLE)
                {
                  funct_state y_l = get_function_state (y);
-                 if (pure_const_state < y_l->pure_const_state)
-                   pure_const_state = y_l->pure_const_state;
-                 if (pure_const_state == IPA_NEITHER)
+                 if (dump_file && (dump_flags & TDF_DETAILS))
+                   {
+                     fprintf (dump_file,
+                              " state:%s looping:%i\n",
+                              pure_const_names[y_l->pure_const_state],
+                              y_l->looping);
+                   }
+                 if (y_l->pure_const_state > IPA_PURE
+                     && cgraph_edge_cannot_lead_to_return (e))
+                   {
+                     if (dump_file && (dump_flags & TDF_DETAILS))
+                       fprintf (dump_file,
+                                "        Ignoring side effects"
+                                " -> pure, looping\n");
+                     edge_state = IPA_PURE;
+                     edge_looping = true;
+                   }
+                 else
+                   {
+                     edge_state = y_l->pure_const_state;
+                     edge_looping = y_l->looping;
+                   }
+               }
+             else if (special_builtin_state (&edge_state, &edge_looping,
+                                              y->decl))
+               ;
+             else
+               state_from_flags (&edge_state, &edge_looping,
+                                 flags_from_decl_or_type (y->decl),
+                                 cgraph_edge_cannot_lead_to_return (e));
+
+             /* Merge the results with what we already know.  */
+             better_state (&edge_state, &edge_looping,
+                           w_l->state_previously_known,
+                           w_l->looping_previously_known);
+             worse_state (&pure_const_state, &looping,
+                          edge_state, edge_looping);
+             if (pure_const_state == IPA_NEITHER)
+               break;
+           }
+         if (pure_const_state == IPA_NEITHER)
+           break;
+
+         /* Now process the indirect call.  */
+          for (ie = w->indirect_calls; ie; ie = ie->next_callee)
+           {
+             enum pure_const_state_e edge_state = IPA_CONST;
+             bool edge_looping = false;
+
+             if (dump_file && (dump_flags & TDF_DETAILS))
+               fprintf (dump_file, "    Indirect call");
+             state_from_flags (&edge_state, &edge_looping,
+                               ie->indirect_info->ecf_flags,
+                               cgraph_edge_cannot_lead_to_return (ie));
+             /* Merge the results with what we already know.  */
+             better_state (&edge_state, &edge_looping,
+                           w_l->state_previously_known,
+                           w_l->looping_previously_known);
+             worse_state (&pure_const_state, &looping,
+                          edge_state, edge_looping);
+             if (pure_const_state == IPA_NEITHER)
+               break;
+           }
+         if (pure_const_state == IPA_NEITHER)
+           break;
+
+         /* And finally all loads and stores.  */
+         for (i = 0; ipa_ref_list_reference_iterate (&w->ref_list, i, ref); i++)
+           {
+             enum pure_const_state_e ref_state = IPA_CONST;
+             bool ref_looping = false;
+             switch (ref->use)
+               {
+               case IPA_REF_LOAD:
+                 /* readonly reads are safe.  */
+                 if (TREE_READONLY (ipa_ref_varpool_node (ref)->decl))
+                   break;
+                 if (dump_file && (dump_flags & TDF_DETAILS))
+                   fprintf (dump_file, "    nonreadonly global var read\n");
+                 ref_state = IPA_PURE;
+                 break;
+               case IPA_REF_STORE:
+                 if (ipa_ref_cannot_lead_to_return (ref))
                    break;
-                 if (y_l->looping)
-                   looping = true;
+                 ref_state = IPA_NEITHER;
+                 if (dump_file && (dump_flags & TDF_DETAILS))
+                   fprintf (dump_file, "    global var write\n");
+                 break;
+               case IPA_REF_ADDR:
+                 break;
                }
+             better_state (&ref_state, &ref_looping,
+                           w_l->state_previously_known,
+                           w_l->looping_previously_known);
+             worse_state (&pure_const_state, &looping,
+                          ref_state, ref_looping);
+             if (pure_const_state == IPA_NEITHER)
+               break;
            }
          w_info = (struct ipa_dfs_info *) w->aux;
          w = w_info->next_cycle;
        }
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf (dump_file, "Result %s looping %i\n",
+                pure_const_names [pure_const_state],
+                looping);
 
       /* Copy back the region's pure_const_state which is shared by
         all nodes in the region.  */
@@ -728,12 +1306,16 @@ propagate (void)
          enum pure_const_state_e this_state = pure_const_state;
          bool this_looping = looping;
 
-         if (w_l->state_set_in_source != IPA_NEITHER)
+         if (w_l->state_previously_known != IPA_NEITHER
+             && this_state > w_l->state_previously_known)
            {
-             if (this_state > w_l->state_set_in_source)
-               this_state = w_l->state_set_in_source;
-             this_looping = false;
+              this_state = w_l->state_previously_known;
+             this_looping |= w_l->looping_previously_known;
            }
+         if (!this_looping && self_recursive_p (w))
+           this_looping = true;
+         if (!w_l->looping_previously_known)
+           this_looping = false;
 
          /* All nodes within a cycle share the same info.  */
          w_l->pure_const_state = this_state;
@@ -742,23 +1324,29 @@ propagate (void)
          switch (this_state)
            {
            case IPA_CONST:
-             if (!TREE_READONLY (w->decl) && dump_file)
-               fprintf (dump_file, "Function found to be %sconst: %s\n",  
-                        this_looping ? "looping " : "",
-                        cgraph_node_name (w)); 
-             TREE_READONLY (w->decl) = 1;
-             DECL_LOOPING_CONST_OR_PURE_P (w->decl) = this_looping;
+             if (!TREE_READONLY (w->decl))
+               {
+                 warn_function_const (w->decl, !this_looping);
+                 if (dump_file)
+                   fprintf (dump_file, "Function found to be %sconst: %s\n",
+                            this_looping ? "looping " : "",
+                            cgraph_node_name (w));
+               }
+             cgraph_set_const_flag (w, true, this_looping);
              break;
-             
+
            case IPA_PURE:
-             if (!DECL_PURE_P (w->decl) && dump_file)
-               fprintf (dump_file, "Function found to be %spure: %s\n",  
-                        this_looping ? "looping " : "",
-                        cgraph_node_name (w)); 
-             DECL_PURE_P (w->decl) = 1;
-             DECL_LOOPING_CONST_OR_PURE_P (w->decl) = this_looping;
+             if (!DECL_PURE_P (w->decl))
+               {
+                 warn_function_pure (w->decl, !this_looping);
+                 if (dump_file)
+                   fprintf (dump_file, "Function found to be %spure: %s\n",
+                            this_looping ? "looping " : "",
+                            cgraph_node_name (w));
+               }
+             cgraph_set_pure_flag (w, true, this_looping);
              break;
-             
+
            default:
              break;
            }
@@ -767,23 +1355,31 @@ propagate (void)
        }
     }
 
-  /* Cleanup. */
-  for (node = cgraph_nodes; node; node = node->next)
-    {
-      /* Get rid of the aux information.  */
-      if (node->aux)
-       {
-         w_info = (struct ipa_dfs_info *) node->aux;
-         free (node->aux);
-         node->aux = NULL;
-       }
-    }
-  order_pos = ipa_utils_reduced_inorder (order, true, false, ignore_edge);
+  ipa_free_postorder_info ();
+  free (order);
+}
+
+/* Produce transitive closure over the callgraph and compute nothrow
+   attributes.  */
+
+static void
+propagate_nothrow (void)
+{
+  struct cgraph_node *node;
+  struct cgraph_node *w;
+  struct cgraph_node **order =
+    XCNEWVEC (struct cgraph_node *, cgraph_n_nodes);
+  int order_pos;
+  int i;
+  struct ipa_dfs_info * w_info;
+
+  order_pos = ipa_reduced_postorder (order, true, false, ignore_edge);
   if (dump_file)
     {
       dump_cgraph (dump_file);
-      ipa_utils_print_order(dump_file, "reduced for nothrow", order, order_pos);
+      ipa_print_order (dump_file, "reduced for nothrow", order, order_pos);
     }
+
   /* Propagate the local information thru the call graph to produce
      the global information.  All the nodes within a cycle will have
      the same info so we collapse cycles first.  Then we can do the
@@ -793,34 +1389,44 @@ propagate (void)
       bool can_throw = false;
       node = order[i];
 
+      if (node->alias)
+       continue;
+
       /* Find the worst state for any node in the cycle.  */
       w = node;
       while (w)
        {
-         struct cgraph_edge *e;
+         struct cgraph_edge *e, *ie;
          funct_state w_l = get_function_state (w);
 
-         if (w_l->can_throw)
+         if (w_l->can_throw
+             || cgraph_function_body_availability (w) == AVAIL_OVERWRITABLE)
            can_throw = true;
 
          if (can_throw)
            break;
-               
-         for (e = w->callees; e; e = e->next_callee) 
+
+         for (e = w->callees; e; e = e->next_callee)
            {
-             struct cgraph_node *y = e->callee;
+             enum availability avail;
+             struct cgraph_node *y = cgraph_function_node (e->callee, &avail);
 
-             if (cgraph_function_body_availability (y) > AVAIL_OVERWRITABLE)
+             if (avail > AVAIL_OVERWRITABLE)
                {
                  funct_state y_l = get_function_state (y);
 
-                 if (can_throw) 
+                 if (can_throw)
                    break;
                  if (y_l->can_throw && !TREE_NOTHROW (w->decl)
                      && e->can_throw_external)
                    can_throw = true;
                }
+             else if (e->can_throw_external && !TREE_NOTHROW (y->decl))
+               can_throw = true;
            }
+          for (ie = node->indirect_calls; ie; ie = ie->next_callee)
+           if (ie->can_throw_external)
+             can_throw = true;
          w_info = (struct ipa_dfs_info *) w->aux;
          w = w_info->next_cycle;
        }
@@ -830,36 +1436,47 @@ propagate (void)
       w = node;
       while (w)
        {
+         funct_state w_l = get_function_state (w);
          if (!can_throw && !TREE_NOTHROW (w->decl))
            {
-             struct cgraph_edge *e;
-             TREE_NOTHROW (w->decl) = true;
-             for (e = w->callers; e; e = e->next_caller)
-               e->can_throw_external = false;
+             cgraph_set_nothrow_flag (w, true);
              if (dump_file)
-               fprintf (dump_file, "Function found to be nothrow: %s\n",  
+               fprintf (dump_file, "Function found to be nothrow: %s\n",
                         cgraph_node_name (w));
            }
+         else if (can_throw && !TREE_NOTHROW (w->decl))
+           w_l->can_throw = true;
          w_info = (struct ipa_dfs_info *) w->aux;
          w = w_info->next_cycle;
        }
     }
 
+  ipa_free_postorder_info ();
+  free (order);
+}
+
+
+/* Produce the global information by preforming a transitive closure
+   on the local information that was produced by generate_summary.  */
+
+static unsigned int
+propagate (void)
+{
+  struct cgraph_node *node;
+
+  cgraph_remove_function_insertion_hook (function_insertion_hook_holder);
+  cgraph_remove_node_duplication_hook (node_duplication_hook_holder);
+  cgraph_remove_node_removal_hook (node_removal_hook_holder);
+
+  /* Nothrow makes more function to not lead to return and improve
+     later analysis.  */
+  propagate_nothrow ();
+  propagate_pure_const ();
+
   /* Cleanup. */
   for (node = cgraph_nodes; node; node = node->next)
-    {
-      /* Get rid of the aux information.  */
-      if (node->aux)
-       {
-         w_info = (struct ipa_dfs_info *) node->aux;
-         free (node->aux);
-         node->aux = NULL;
-       }
-      if (cgraph_function_body_availability (node) > AVAIL_OVERWRITABLE)
-       free (get_function_state (node));
-    }
-  
-  free (order);
+    if (has_function_state (node))
+      free (get_function_state (node));
   VEC_free (funct_state, heap, funct_state_vec);
   finish_state ();
   return 0;
@@ -870,10 +1487,10 @@ gate_pure_const (void)
 {
   return (flag_ipa_pure_const
          /* Don't bother doing anything if the program has errors.  */
-         && !(errorcount || sorrycount));
+         && !seen_error ());
 }
 
-struct ipa_opt_pass pass_ipa_pure_const =
+struct ipa_opt_pass_d pass_ipa_pure_const =
 {
  {
   IPA_PASS,
@@ -891,14 +1508,39 @@ struct ipa_opt_pass pass_ipa_pure_const =
   0                                     /* todo_flags_finish */
  },
  generate_summary,                     /* generate_summary */
- NULL,                                 /* write_summary */
- NULL,                                 /* read_summary */
- NULL,                                 /* function_read_summary */
+ pure_const_write_summary,             /* write_summary */
+ pure_const_read_summary,              /* read_summary */
+ NULL,                                 /* write_optimization_summary */
+ NULL,                                 /* read_optimization_summary */
+ NULL,                                 /* stmt_fixup */
  0,                                    /* TODOs */
  NULL,                                 /* function_transform */
  NULL                                  /* variable_transform */
 };
 
+/* Return true if function should be skipped for local pure const analysis.  */
+
+static bool
+skip_function_for_local_pure_const (struct cgraph_node *node)
+{
+  /* Because we do not schedule pass_fixup_cfg over whole program after early optimizations
+     we must not promote functions that are called by already processed functions.  */
+
+  if (function_called_by_processed_nodes_p ())
+    {
+      if (dump_file)
+        fprintf (dump_file, "Function called in recursive cycle; ignoring\n");
+      return true;
+    }
+  if (cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE)
+    {
+      if (dump_file)
+        fprintf (dump_file, "Function is not available or overwritable; not analyzing.\n");
+      return true;
+    }
+  return false;
+}
+
 /* Simple local pass for pure const discovery reusing the analysis from
    ipa_pure_const.   This pass is effective when executed together with
    other optimization passes in early optimization pass queue.  */
@@ -908,23 +1550,33 @@ local_pure_const (void)
 {
   bool changed = false;
   funct_state l;
+  bool skip;
+  struct cgraph_node *node;
 
-  /* Because we do not schedule pass_fixup_cfg over whole program after early optimizations
-     we must not promote functions that are called by already processed functions.  */
+  node = cgraph_get_node (current_function_decl);
+  skip = skip_function_for_local_pure_const (node);
+  if (!warn_suggest_attribute_const
+      && !warn_suggest_attribute_pure
+      && skip)
+    return 0;
 
-  if (function_called_by_processed_nodes_p ())
-    {
-      if (dump_file)
-        fprintf (dump_file, "Function called in recursive cycle; ignoring\n");
-      return 0;
-    }
+  l = analyze_function (node, false);
 
-  l = analyze_function (cgraph_node (current_function_decl), false);
-  if (!l)
+  /* Do NORETURN discovery.  */
+  if (!skip && !TREE_THIS_VOLATILE (current_function_decl)
+      && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0)
     {
+      warn_function_noreturn (cfun->decl);
       if (dump_file)
-        fprintf (dump_file, "Function has wrong visibility; ignoring\n");
-      return 0;
+        fprintf (dump_file, "Function found to be noreturn: %s\n",
+                lang_hooks.decl_printable_name (current_function_decl, 2));
+
+      /* Update declaration and reduce profile to executed once.  */
+      TREE_THIS_VOLATILE (current_function_decl) = 1;
+      if (node->frequency > NODE_FREQUENCY_EXECUTED_ONCE)
+        node->frequency = NODE_FREQUENCY_EXECUTED_ONCE;
+
+      changed = true;
     }
 
   switch (l->pure_const_state)
@@ -932,9 +1584,12 @@ local_pure_const (void)
     case IPA_CONST:
       if (!TREE_READONLY (current_function_decl))
        {
-         TREE_READONLY (current_function_decl) = 1;
-         DECL_LOOPING_CONST_OR_PURE_P (current_function_decl) = l->looping;
-         changed = true;
+         warn_function_const (current_function_decl, !l->looping);
+         if (!skip)
+           {
+             cgraph_set_const_flag (node, true, l->looping);
+             changed = true;
+           }
          if (dump_file)
            fprintf (dump_file, "Function found to be %sconst: %s\n",
                     l->looping ? "looping " : "",
@@ -944,8 +1599,11 @@ local_pure_const (void)
       else if (DECL_LOOPING_CONST_OR_PURE_P (current_function_decl)
               && !l->looping)
        {
-         DECL_LOOPING_CONST_OR_PURE_P (current_function_decl) = false;
-         changed = true;
+         if (!skip)
+           {
+             cgraph_set_const_flag (node, true, false);
+             changed = true;
+           }
          if (dump_file)
            fprintf (dump_file, "Function found to be non-looping: %s\n",
                     lang_hooks.decl_printable_name (current_function_decl,
@@ -954,11 +1612,14 @@ local_pure_const (void)
       break;
 
     case IPA_PURE:
-      if (!TREE_READONLY (current_function_decl))
+      if (!DECL_PURE_P (current_function_decl))
        {
-         DECL_PURE_P (current_function_decl) = 1;
-         DECL_LOOPING_CONST_OR_PURE_P (current_function_decl) = l->looping;
-         changed = true;
+         if (!skip)
+           {
+             cgraph_set_pure_flag (node, true, l->looping);
+             changed = true;
+           }
+         warn_function_pure (current_function_decl, !l->looping);
          if (dump_file)
            fprintf (dump_file, "Function found to be %spure: %s\n",
                     l->looping ? "looping " : "",
@@ -968,8 +1629,11 @@ local_pure_const (void)
       else if (DECL_LOOPING_CONST_OR_PURE_P (current_function_decl)
               && !l->looping)
        {
-         DECL_LOOPING_CONST_OR_PURE_P (current_function_decl) = false;
-         changed = true;
+         if (!skip)
+           {
+             cgraph_set_pure_flag (node, true, false);
+             changed = true;
+           }
          if (dump_file)
            fprintf (dump_file, "Function found to be non-looping: %s\n",
                     lang_hooks.decl_printable_name (current_function_decl,
@@ -982,20 +1646,14 @@ local_pure_const (void)
     }
   if (!l->can_throw && !TREE_NOTHROW (current_function_decl))
     {
-      struct cgraph_edge *e;
-
-      TREE_NOTHROW (current_function_decl) = true;
-      for (e = cgraph_node (current_function_decl)->callers;
-           e; e = e->next_caller)
-       e->can_throw_external = false;
+      cgraph_set_nothrow_flag (node, true);
       changed = true;
       if (dump_file)
        fprintf (dump_file, "Function found to be nothrow: %s\n",
                 lang_hooks.decl_printable_name (current_function_decl,
                                                 2));
     }
-  if (l)
-    free (l);
+  free (l);
   if (changed)
     return execute_fixup_cfg ();
   else