[PATCH] Pass in avail_expr_stack and setup edge_infos earlier

PR tree-optimization/47679
	* tree-ssa-dom.c (free_edge_info): Factored out of free_all_edge_infos.
	(free_all_edge_infos): Use it.
	(allocate_edge_info): Free preexisting edge info data.
	(pass_dominator::execute): Set up initial edge info structures.
	(dom_opt_dom_walker::thread_across_edge): Pass avail_expr_stack to
	thread_across_edge.
	* tree-ssa-threadedge.c (thread_across_edge): Accept new argument.  If
	non-null, then push/pop markers appropriately.
	* tree-ssa-threadedge.h (thread_across_edge): Update prototype.
	* tree-vrp.c (identify_jump_threads): Pass NULL for new argument to
	thread-across_edge.

From-SVN: r227842

gcc/ChangeLog

@@ -1,3 +1,18 @@
+2015-09-16  Jeff Law  <law@redhat.com>
+
+	PR tree-optimization/47679
+	* tree-ssa-dom.c (free_edge_info): Factored out of free_all_edge_infos.
+	(free_all_edge_infos): Use it.
+	(allocate_edge_info): Free preexisting edge info data.
+	(pass_dominator::execute): Set up initial edge info structures.
+	(dom_opt_dom_walker::thread_across_edge): Pass avail_expr_stack to
+	thread_across_edge.
+	* tree-ssa-threadedge.c (thread_across_edge): Accept new argument.  If
+	non-null, then push/pop markers appropriately.
+	* tree-ssa-threadedge.h (thread_across_edge): Update prototype.
+	* tree-vrp.c (identify_jump_threads): Pass NULL for new argument to
+	thread-across_edge.
+
 2015-09-16  James Bowman  <james.bowman@ftdichip.com>
 
 	* config/ft32/ft32.c Fix the memory address space predicate.

gcc/tree-ssa-dom.c

@@ -132,6 +132,20 @@ static void eliminate_redundant_computations (gimple_stmt_iterator *);
 static void record_equivalences_from_stmt (gimple, int);
 static edge single_incoming_edge_ignoring_loop_edges (basic_block);
 
+/* Free the edge_info data attached to E, if it exists.  */
+
+static void
+free_edge_info (edge e)
+{
+  struct edge_info *edge_info = (struct edge_info *)e->aux;
+
+  if (edge_info)
+    {
+      edge_info->cond_equivalences.release ();
+      free (edge_info);
+    }
+}
+
 /* Allocate an EDGE_INFO for edge E and attach it to E.
    Return the new EDGE_INFO structure.  */
 
@@ -140,6 +154,9 @@ allocate_edge_info (edge e)
 {
   struct edge_info *edge_info;
 
+  /* Free the old one, if it exists.  */
+  free_edge_info (e);
+
   edge_info = XCNEW (struct edge_info);
 
   e->aux = edge_info;
@@ -163,14 +180,8 @@ free_all_edge_infos (void)
     {
       FOR_EACH_EDGE (e, ei, bb->preds)
         {
-	 struct edge_info *edge_info = (struct edge_info *) e->aux;
-
-	  if (edge_info)
-	    {
-	      edge_info->cond_equivalences.release ();
-	      free (edge_info);
-	      e->aux = NULL;
-	    }
+	  free_edge_info (e);
+	  e->aux = NULL;
 	}
     }
 }
@@ -574,6 +585,16 @@ pass_dominator::execute (function *fun)
      a single loop.  */
   mark_dfs_back_edges ();
 
+  /* We want to create the edge info structures before the dominator walk
+     so that they'll be in place for the jump threader, particularly when
+     threading through a join block.
+
+     The conditions will be lazily updated with global equivalences as
+     we reach them during the dominator walk.  */
+  basic_block bb;
+  FOR_EACH_BB_FN (bb, fun)
+    record_edge_info (bb);
+
   /* Recursively walk the dominator tree optimizing statements.  */
   dom_opt_dom_walker (CDI_DOMINATORS).walk (fun->cfg->x_entry_block_ptr);
 
@@ -873,7 +894,7 @@ dom_opt_dom_walker::thread_across_edge (edge e)
   /* With all the edge equivalences in the tables, go ahead and attempt
      to thread through E->dest.  */
   ::thread_across_edge (m_dummy_cond, e, false,
-		        const_and_copies,
+		        const_and_copies, avail_exprs_stack,
 		        simplify_stmt_for_jump_threading);
 
   /* And restore the various tables to their state before

gcc/tree-ssa-threadedge.c

@@ -1358,6 +1358,7 @@ thread_across_edge (gcond *dummy_cond,
 		    edge e,
 		    bool handle_dominating_asserts,
 		    const_and_copies *const_and_copies,
+		    avail_exprs_stack *avail_exprs_stack,
 		    tree (*simplify) (gimple, gimple))
 {
   bitmap visited = BITMAP_ALLOC (NULL);
@@ -1442,6 +1443,8 @@ thread_across_edge (gcond *dummy_cond,
 	/* Push a fresh marker so we can unwind the equivalences created
 	   for each of E->dest's successors.  */
 	const_and_copies->push_marker ();
+	if (avail_exprs_stack)
+	  avail_exprs_stack->push_marker ();
      
 	/* Avoid threading to any block we have already visited.  */
 	bitmap_clear (visited);
@@ -1493,6 +1496,8 @@ thread_across_edge (gcond *dummy_cond,
 	  }
 
 	/* And unwind the equivalence table.  */
+	if (avail_exprs_stack)
+	  avail_exprs_stack->pop_to_marker ();
 	const_and_copies->pop_to_marker ();
       }
     BITMAP_FREE (visited);

gcc/tree-ssa-threadedge.h

@@ -31,6 +31,8 @@ extern void threadedge_finalize_values (void);
 extern bool potentially_threadable_block (basic_block);
 extern void propagate_threaded_block_debug_into (basic_block, basic_block);
 extern void thread_across_edge (gcond *, edge, bool,
-				const_and_copies *, tree (*) (gimple, gimple));
+				const_and_copies *,
+				avail_exprs_stack *,
+				tree (*) (gimple, gimple));
 
 #endif /* GCC_TREE_SSA_THREADEDGE_H */

gcc/tree-vrp.c

@@ -10205,7 +10205,7 @@ identify_jump_threads (void)
 	      if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
 		continue;
 
-	      thread_across_edge (dummy, e, true, equiv_stack,
+	      thread_across_edge (dummy, e, true, equiv_stack, NULL,
 				  simplify_stmt_for_jump_threading);
 	    }
 	}