More profile updating fixes

[Jan Hubicka <hubicka at ucw dot cz>]

Hi,
here are less trivial updates to profile code which I did not bundle into
initial transition.  Those are not bugs in old code, just new code needs
to track more.

profile-bootstrapped/regtested x86_64-linux, will commit it shortly.
	* cfgexpand.c (expand_gimple_tailcall): Initialize profile of
	new edge.
	* ipa-inline.c (want_inline_self_recursive_call_p): Watch for missing
	profile in callgraph edge.
	* profile-count.h (apply_probability): If THIS is 0, then result is 0
	(apply_scale): Likewise.
	* tree-inline.c (copy_bb, copy_edges_for_bb, copy_cfg_body):
	Also scale profile when inlining function with zero profile.
	(initialize_cfun): Update exit block profile even when it is zero.
	* tree-ssa-threadupdate.c (clear_counts_path): Handle correctly case
	when profile is read.
Index: cfgexpand.c
===================================================================
--- cfgexpand.c	(revision 248871)
+++ cfgexpand.c	(working copy)
@@ -3850,8 +3850,8 @@ expand_gimple_tailcall (basic_block bb,
 
   e = make_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun), EDGE_ABNORMAL
 		 | EDGE_SIBCALL);
-  e->probability += probability;
-  e->count += count;
+  e->probability = probability;
+  e->count = count;
   BB_END (bb) = last;
   update_bb_for_insn (bb);
 
Index: ipa-inline.c
===================================================================
--- ipa-inline.c	(revision 248871)
+++ ipa-inline.c	(working copy)
@@ -912,7 +912,7 @@ want_inline_self_recursive_call_p (struc
      methods.  */
   else
     {
-      if (max_count > profile_count::zero ()
+      if (max_count > profile_count::zero () && edge->count.initialized_p ()
 	  && (edge->count.to_gcov_type () * 100
 	      / outer_node->count.to_gcov_type ()
 	      <= PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY)))
@@ -920,7 +920,8 @@ want_inline_self_recursive_call_p (struc
 	  reason = "profile of recursive call is too small";
 	  want_inline = false;
 	}
-      else if (max_count == profile_count::zero ()
+      else if ((max_count == profile_count::zero ()
+	        || !edge->count.initialized_p ())
 	       && (edge->frequency * 100 / caller_freq
 	           <= PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY)))
 	{
Index: profile-count.h
===================================================================
--- profile-count.h	(revision 248871)
+++ profile-count.h	(working copy)
@@ -221,6 +221,8 @@ public:
   profile_count apply_probability (int prob) const
     {
       gcc_checking_assert (prob >= 0 && prob <= REG_BR_PROB_BASE);
+      if (*this == profile_count::zero ())
+	return *this;
       if (!initialized_p ())
 	return profile_count::uninitialized ();
       profile_count ret;
@@ -230,6 +232,8 @@ public:
   /* Return *THIS * NUM / DEN.  */
   profile_count apply_scale (int64_t num, int64_t den) const
     {
+      if (*this == profile_count::zero ())
+	return *this;
       if (!initialized_p ())
 	return profile_count::uninitialized ();
       profile_count ret;
@@ -243,7 +247,7 @@ public:
     }
   profile_count apply_scale (profile_count num, profile_count den) const
     {
-      if (*this == profile_count::zero ())
+      if (*this == profile_count::zero () || num == profile_count::zero ())
 	return profile_count::zero ();
       if (!initialized_p () || !num.initialized_p () || !den.initialized_p ())
 	return profile_count::uninitialized ();
Index: tree-inline.c
===================================================================
--- tree-inline.c	(revision 248871)
+++ tree-inline.c	(working copy)
@@ -1763,7 +1763,8 @@ copy_bb (copy_body_data *id, basic_block
   tree decl;
   gcov_type freq;
   basic_block prev;
-  bool scale = num.initialized_p () && den.initialized_p () && den > 0;
+  bool scale = num.initialized_p ()
+	       && (den > 0 || num == profile_count::zero ());
 
   /* Search for previous copied basic block.  */
   prev = bb->prev_bb;
@@ -2211,7 +2212,8 @@ copy_edges_for_bb (basic_block bb, profi
   gimple_stmt_iterator si;
   int flags;
   bool need_debug_cleanup = false;
-  bool scale = num.initialized_p () && den.initialized_p () && den > 0;
+  bool scale = num.initialized_p ()
+	       && (den > 0 || num == profile_count::zero ());
 
   /* Use the indices from the original blocks to create edges for the
      new ones.  */
@@ -2472,7 +2474,7 @@ initialize_cfun (tree new_fndecl, tree c
    */
   if (ENTRY_BLOCK_PTR_FOR_FN (src_cfun)->count.initialized_p ()
       && count.initialized_p ()
-      && ENTRY_BLOCK_PTR_FOR_FN (src_cfun)->count > 0)
+      && ENTRY_BLOCK_PTR_FOR_FN (src_cfun)->count.initialized_p ())
     {
       ENTRY_BLOCK_PTR_FOR_FN (cfun)->count =
 	ENTRY_BLOCK_PTR_FOR_FN (src_cfun)->count.apply_scale (count,
@@ -2683,7 +2685,8 @@ copy_cfg_body (copy_body_data * id, prof
   profile_count incoming_count = profile_count::zero ();
   profile_count num = count;
   profile_count den = ENTRY_BLOCK_PTR_FOR_FN (src_cfun)->count;
-  bool scale = num.initialized_p () && den.initialized_p () && den > 0;
+  bool scale = num.initialized_p ()
+	       && (den > 0 || num == profile_count::zero ());
 
   /* This can happen for COMDAT routines that end up with 0 counts
      despite being called (see the comments for handle_missing_profiles()
Index: tree-ssa-threadupdate.c
===================================================================
--- tree-ssa-threadupdate.c	(revision 248871)
+++ tree-ssa-threadupdate.c	(working copy)
@@ -1084,16 +1084,20 @@ clear_counts_path (struct redirection_da
   vec<jump_thread_edge *> *path = THREAD_PATH (e);
   edge ein, esucc;
   edge_iterator ei;
+  profile_count val = profile_count::uninitialized ();
+  if (profile_status_for_fn (cfun) == PROFILE_READ)
+    val = profile_count::zero ();
+
   FOR_EACH_EDGE (ein, ei, e->dest->preds)
-    ein->count = profile_count::uninitialized ();
+    ein->count = val;
 
   /* First clear counts along original path.  */
   for (unsigned int i = 1; i < path->length (); i++)
     {
       edge epath = (*path)[i]->e;
       FOR_EACH_EDGE (esucc, ei, epath->src->succs)
-	esucc->count = profile_count::uninitialized ();
-      epath->src->count = profile_count::uninitialized ();
+	esucc->count = val;
+      epath->src->count = val;
     }
   /* Also need to clear the counts along duplicated path.  */
   for (unsigned int i = 0; i < 2; i++)
@@ -1102,8 +1106,8 @@ clear_counts_path (struct redirection_da
       if (!dup)
 	continue;
       FOR_EACH_EDGE (esucc, ei, dup->succs)
-	esucc->count = profile_count::uninitialized ();
-      dup->count = profile_count::uninitialized ();
+	esucc->count = val;
+      dup->count = val;
     }
 }