* cgraph.c (cgraph_turn_edge_to_speculative): Return newly

	introduced edge; fix typo in sanity check.
	(cgraph_resolve_speculation): Export; improve diagnostic.
	(cgraph_redirect_edge_call_stmt_to_callee): Better diagnostic; cancel
	speculation at type mismatch.
	* cgraph.h (cgraph_turn_edge_to_speculative): Update.
	(cgraph_resolve_speculation): Declare.
	(symtab_can_be_discarded): New function.
	* value-prof.c (gimple_ic_transform): Remove actual transform code.
	* ipa-inline-transform.c (speculation_removed): New global var.
	(clone_inlined_nodes): See if speculation can be removed.
	(inline_call): If speculations was removed, we growths may not match.
	* ipa-inline.c (can_inline_edge_p): Add DISREGARD_LIMITS parameter.
	(speculation_useful_p): New function.
	(resolve_noninline_speculation): New function.
	(inline_small_functions): Resolve useless speculations.
	* ipa-inline.h (speculation_useful_p): Declare
	* ipa.c (can_replace_by_local_alias): Simplify.
	(ipa_profile): Produce speculative calls in non-lto, too;
	add simple cost model; produce local aliases.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@201683 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 191 insertions, 64 deletions

diff --git a/gcc/ipa-inline.c b/gcc/ipa-inline.c
index 033b314b34a..a9eb1ad75a6 100644
--- a/gcc/ipa-inline.c
+++ b/gcc/ipa-inline.c
@@ -229,10 +229,13 @@ report_inline_failed_reason (struct cgraph_edge *e)
    We check whether inlining is possible at all and whether
    caller growth limits allow doing so.  
 
-   if REPORT is true, output reason to the dump file.  */
+   if REPORT is true, output reason to the dump file.  
+
+   if DISREGARD_LIMITES is true, ignore size limits.*/
 
 static bool
-can_inline_edge_p (struct cgraph_edge *e, bool report)
+can_inline_edge_p (struct cgraph_edge *e, bool report,
+		   bool disregard_limits = false)
 {
   bool inlinable = true;
   enum availability avail;
@@ -309,6 +312,7 @@ can_inline_edge_p (struct cgraph_edge *e, bool report)
     }
   /* Check if caller growth allows the inlining.  */
   else if (!DECL_DISREGARD_INLINE_LIMITS (callee->symbol.decl)
+	   && !disregard_limits
 	   && !lookup_attribute ("flatten",
 				 DECL_ATTRIBUTES
 				   (e->caller->global.inlined_to
@@ -1400,6 +1404,79 @@ heap_edge_removal_hook (struct cgraph_edge *e, void *data)
     }
 }
 
+/* Return true if speculation of edge E seems useful.
+   If ANTICIPATE_INLINING is true, be conservative and hope that E
+   may get inlined.  */
+
+bool
+speculation_useful_p (struct cgraph_edge *e, bool anticipate_inlining)
+{
+  enum availability avail;
+  struct cgraph_node *target = cgraph_function_or_thunk_node (e->callee, &avail);
+  struct cgraph_edge *direct, *indirect;
+  struct ipa_ref *ref;
+
+  gcc_assert (e->speculative && !e->indirect_unknown_callee);
+
+  if (!cgraph_maybe_hot_edge_p (e))
+    return false;
+
+  /* See if IP optimizations found something potentially useful about the
+     function.  For now we look only for CONST/PURE flags.  Almost everything
+     else we propagate is useless.  */
+  if (avail >= AVAIL_AVAILABLE)
+    {
+      int ecf_flags = flags_from_decl_or_type (target->symbol.decl);
+      if (ecf_flags & ECF_CONST)
+        {
+          cgraph_speculative_call_info (e, direct, indirect, ref);
+	  if (!(indirect->indirect_info->ecf_flags & ECF_CONST))
+	    return true;
+        }
+      else if (ecf_flags & ECF_PURE)
+        {
+          cgraph_speculative_call_info (e, direct, indirect, ref);
+	  if (!(indirect->indirect_info->ecf_flags & ECF_PURE))
+	    return true;
+        }
+    }
+  /* If we did not managed to inline the function nor redirect
+     to an ipa-cp clone (that are seen by having local flag set),
+     it is probably pointless to inline it unless hardware is missing
+     indirect call predictor.  */
+  if (!anticipate_inlining && e->inline_failed && !target->local.local)
+    return false;
+  /* For overwritable targets there is not much to do.  */
+  if (e->inline_failed && !can_inline_edge_p (e, false, true))
+    return false;
+  /* OK, speculation seems interesting.  */
+  return true;
+}
+
+/* We know that EDGE is not going to be inlined.
+   See if we can remove speculation.  */
+
+static void
+resolve_noninline_speculation (fibheap_t edge_heap, struct cgraph_edge *edge)
+{
+  if (edge->speculative && !speculation_useful_p (edge, false))
+    {
+      struct cgraph_node *node = edge->caller;
+      struct cgraph_node *where = node->global.inlined_to
+				  ? node->global.inlined_to : node;
+      bitmap updated_nodes = BITMAP_ALLOC (NULL);
+
+      cgraph_resolve_speculation (edge, NULL);
+      reset_node_growth_cache (where);
+      reset_edge_caches (where);
+      inline_update_overall_summary (where);
+      update_caller_keys (edge_heap, where,
+			  updated_nodes, NULL);
+      reset_node_growth_cache (where);
+      BITMAP_FREE (updated_nodes);
+    }
+}
+
 /* We use greedy algorithm for inlining of small functions:
    All inline candidates are put into prioritized heap ordered in
    increasing badness.
@@ -1478,14 +1555,19 @@ inline_small_functions (void)
   /* Populate the heeap with all edges we might inline.  */
 
   FOR_EACH_DEFINED_FUNCTION (node)
-    if (!node->global.inlined_to)
-      {
-	if (dump_file)
-	  fprintf (dump_file, "Enqueueing calls of %s/%i.\n",
-		   cgraph_node_name (node), node->symbol.order);
+    {
+      bool update = false;
+      struct cgraph_edge *next;
 
-	for (edge = node->callers; edge; edge = edge->next_caller)
+      if (dump_file)
+	fprintf (dump_file, "Enqueueing calls in %s/%i.\n",
+		 cgraph_node_name (node), node->symbol.order);
+
+      for (edge = node->callees; edge; edge = next)
+	{
+	  next = edge->next_callee;
 	  if (edge->inline_failed
+	      && !edge->aux
 	      && can_inline_edge_p (edge, true)
 	      && want_inline_small_function_p (edge, true)
 	      && edge->inline_failed)
@@ -1493,7 +1575,24 @@ inline_small_functions (void)
 	      gcc_assert (!edge->aux);
 	      update_edge_key (edge_heap, edge);
 	    }
-      }
+	  if (edge->speculative && !speculation_useful_p (edge, edge->aux != NULL))
+	    {
+	      cgraph_resolve_speculation (edge, NULL);
+	      update = true;
+	    }
+	}
+      if (update)
+	{
+	  struct cgraph_node *where = node->global.inlined_to
+				      ? node->global.inlined_to : node;
+	  inline_update_overall_summary (where);
+          reset_node_growth_cache (where);
+	  reset_edge_caches (where);
+          update_caller_keys (edge_heap, where,
+			      updated_nodes, NULL);
+          bitmap_clear (updated_nodes);
+	}
+    }
 
   gcc_assert (in_lto_p
 	      || !max_count
@@ -1534,7 +1633,10 @@ inline_small_functions (void)
 	}
 
       if (!can_inline_edge_p (edge, true))
-	continue;
+	{
+	  resolve_noninline_speculation (edge_heap, edge);
+	  continue;
+	}
       
       callee = cgraph_function_or_thunk_node (edge->callee, NULL);
       growth = estimate_edge_growth (edge);
@@ -1568,11 +1670,15 @@ inline_small_functions (void)
 	{
 	  edge->inline_failed = CIF_INLINE_UNIT_GROWTH_LIMIT;
 	  report_inline_failed_reason (edge);
+	  resolve_noninline_speculation (edge_heap, edge);
 	  continue;
 	}
 
       if (!want_inline_small_function_p (edge, true))
-	continue;
+	{
+	  resolve_noninline_speculation (edge_heap, edge);
+	  continue;
+	}
 
       /* Heuristics for inlining small functions works poorly for
 	 recursive calls where we do efect similar to loop unrolling.
@@ -1588,6 +1694,7 @@ inline_small_functions (void)
 				   ? &new_indirect_edges : NULL))
 	    {
 	      edge->inline_failed = CIF_RECURSIVE_INLINING;
+	      resolve_noninline_speculation (edge_heap, edge);
 	      continue;
 	    }
 	  reset_edge_caches (where);
@@ -1596,6 +1703,7 @@ inline_small_functions (void)
 	  if (flag_indirect_inlining)
 	    add_new_edges_to_heap (edge_heap, new_indirect_edges);
           update_callee_keys (edge_heap, where, updated_nodes);
+	  bitmap_clear (updated_nodes);
 	}
       else
 	{
@@ -1621,6 +1729,7 @@ inline_small_functions (void)
 	      edge->inline_failed
 		= (DECL_DISREGARD_INLINE_LIMITS (edge->callee->symbol.decl)
 		   ? CIF_RECURSIVE_INLINING : CIF_UNSPECIFIED);
+	      resolve_noninline_speculation (edge_heap, edge);
 	      continue;
 	    }
 	  else if (depth && dump_file)
@@ -1773,6 +1882,7 @@ ipa_inline (void)
   struct cgraph_node **order =
     XCNEWVEC (struct cgraph_node *, cgraph_n_nodes);
   int i;
+  int cold;
 
   if (in_lto_p && optimize)
     ipa_update_after_lto_read ();
@@ -1820,66 +1930,83 @@ ipa_inline (void)
      code size will shrink because the out-of-line copy is eliminated. 
      We do this regardless on the callee size as long as function growth limits
      are met.  */
-  if (flag_inline_functions_called_once)
+  if (dump_file)
+    fprintf (dump_file,
+	     "\nDeciding on functions to be inlined into all callers and removing useless speculations:\n");
+
+  /* Inlining one function called once has good chance of preventing
+     inlining other function into the same callee.  Ideally we should
+     work in priority order, but probably inlining hot functions first
+     is good cut without the extra pain of maintaining the queue.
+
+     ??? this is not really fitting the bill perfectly: inlining function
+     into callee often leads to better optimization of callee due to
+     increased context for optimization.
+     For example if main() function calls a function that outputs help
+     and then function that does the main optmization, we should inline
+     the second with priority even if both calls are cold by themselves.
+
+     We probably want to implement new predicate replacing our use of
+     maybe_hot_edge interpreted as maybe_hot_edge || callee is known
+     to be hot.  */
+  for (cold = 0; cold <= 1; cold ++)
     {
-      int cold;
-      if (dump_file)
-	fprintf (dump_file,
-		 "\nDeciding on functions to be inlined into all callers:\n");
-
-      /* Inlining one function called once has good chance of preventing
-	 inlining other function into the same callee.  Ideally we should
-	 work in priority order, but probably inlining hot functions first
-	 is good cut without the extra pain of maintaining the queue.
-
-	 ??? this is not really fitting the bill perfectly: inlining function
-	 into callee often leads to better optimization of callee due to
-	 increased context for optimization.
-	 For example if main() function calls a function that outputs help
-	 and then function that does the main optmization, we should inline
-	 the second with priority even if both calls are cold by themselves.
-
-	 We probably want to implement new predicate replacing our use of
-	 maybe_hot_edge interpreted as maybe_hot_edge || callee is known
-	 to be hot.  */
-      for (cold = 0; cold <= 1; cold ++)
+      FOR_EACH_DEFINED_FUNCTION (node)
 	{
-	  FOR_EACH_DEFINED_FUNCTION (node)
+	  struct cgraph_edge *edge, *next;
+	  bool update=false;
+
+	  for (edge = node->callees; edge; edge = next)
 	    {
-	      if (want_inline_function_to_all_callers_p (node, cold))
+	      next = edge->next_callee;
+	      if (edge->speculative && !speculation_useful_p (edge, false))
 		{
-		  int num_calls = 0;
-		  struct cgraph_edge *e;
-		  for (e = node->callers; e; e = e->next_caller)
-		    num_calls++;
-		  while (node->callers && !node->global.inlined_to)
+		  cgraph_resolve_speculation (edge, NULL);
+		  update = true;
+		}
+	    }
+	  if (update)
+	    {
+	      struct cgraph_node *where = node->global.inlined_to
+					  ? node->global.inlined_to : node;
+              reset_node_growth_cache (where);
+	      reset_edge_caches (where);
+	      inline_update_overall_summary (where);
+	    }
+	  if (flag_inline_functions_called_once
+	      && want_inline_function_to_all_callers_p (node, cold))
+	    {
+	      int num_calls = 0;
+	      struct cgraph_edge *e;
+	      for (e = node->callers; e; e = e->next_caller)
+		num_calls++;
+	      while (node->callers && !node->global.inlined_to)
+		{
+		  struct cgraph_node *caller = node->callers->caller;
+
+		  if (dump_file)
 		    {
-		      struct cgraph_node *caller = node->callers->caller;
+		      fprintf (dump_file,
+			       "\nInlining %s size %i.\n",
+			       cgraph_node_name (node),
+			       inline_summary (node)->size);
+		      fprintf (dump_file,
+			       " Called once from %s %i insns.\n",
+			       cgraph_node_name (node->callers->caller),
+			       inline_summary (node->callers->caller)->size);
+		    }
 
+		  inline_call (node->callers, true, NULL, NULL, true);
+		  if (dump_file)
+		    fprintf (dump_file,
+			     " Inlined into %s which now has %i size\n",
+			     cgraph_node_name (caller),
+			     inline_summary (caller)->size);
+		  if (!num_calls--)
+		    {
 		      if (dump_file)
-			{
-			  fprintf (dump_file,
-				   "\nInlining %s size %i.\n",
-				   cgraph_node_name (node),
-				   inline_summary (node)->size);
-			  fprintf (dump_file,
-				   " Called once from %s %i insns.\n",
-				   cgraph_node_name (node->callers->caller),
-				   inline_summary (node->callers->caller)->size);
-			}
-
-		      inline_call (node->callers, true, NULL, NULL, true);
-		      if (dump_file)
-			fprintf (dump_file,
-				 " Inlined into %s which now has %i size\n",
-				 cgraph_node_name (caller),
-				 inline_summary (caller)->size);
-		      if (!num_calls--)
-		        {
-			  if (dump_file)
-			    fprintf (dump_file, "New calls found; giving up.\n");
-			  break;
-		        }
+			fprintf (dump_file, "New calls found; giving up.\n");
+		      break;
 		    }
 		}
 	    }