[PATCH] Fix 47679 by improving jump threading

	PR tree-optimization/47679
	* tree-ssa-dom.c (record_temporary_equivalences): No longer static.
	* tree-ssa-dom.h (record_temporary_equivalences): Add prototype.
	* tree-ssa-threadedge.c: Include tree-ssa-dom.h.
	(thread_through_normal_block): Use record_temporary_equivalences.

        PR tree-optimization/47679
	* g++.dg/warn/Wuninitialized-6.C: New test.

From-SVN: r227942

gcc/ChangeLog

+2015-09-20  Jeff Law  <law@redhat.com>
+
+	PR tree-optimization/47679
+	* tree-ssa-dom.c (record_temporary_equivalences): No longer static.
+	* tree-ssa-dom.h (record_temporary_equivalences): Add prototype.
+	* tree-ssa-threadedge.c: Include tree-ssa-dom.h.
+	(thread_through_normal_block): Use record_temporary_equivalences.
+
 2015-09-19  Trevor Saunders  <tbsaunde@tbsaunde.org>
 
 	* coretypes.h (gimple): Change typedef to be a forward

gcc/testsuite/ChangeLog

+2015-09-20  Jeff Law  <law@redhat.com>
+
+        PR tree-optimization/47679
+	* g++.dg/warn/Wuninitialized-6.C: New test.
+
 2015-09-18  Ville Voutilainen  <ville.voutilainen@gmail.com>
 
 	Implement nested namespace definitions.

gcc/tree-ssa-dom.c

@@ -780,7 +780,7 @@ dom_valueize (tree t)
    by traversing edge E (which are cached in E->aux).
 
    Callers are responsible for managing the unwinding markers.  */
-static void
+void
 record_temporary_equivalences (edge e,
 			       class const_and_copies *const_and_copies,
 			       class avail_exprs_stack *avail_exprs_stack)

gcc/tree-ssa-dom.h

@@ -21,5 +21,8 @@ along with GCC; see the file COPYING3.  If not see
 #define GCC_TREE_SSA_DOM_H
 
 extern bool simple_iv_increment_p (gimple *);
+extern void record_temporary_equivalences (edge,
+					   class const_and_copies *,
+					   class avail_exprs_stack *);
 
 #endif /* GCC_TREE_SSA_DOM_H */

gcc/tree-ssa-threadedge.c

@@ -44,6 +44,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-ssa-scopedtables.h"
 #include "tree-ssa-threadedge.h"
 #include "tree-ssa-loop.h"
+#include "tree-ssa-dom.h"
 #include "builtins.h"
 #include "cfganal.h"
 
@@ -1213,6 +1214,10 @@ thread_through_normal_block (edge e,
   if (*backedge_seen_p)
     simplify = dummy_simplify;
 
+  /* We want to record any equivalences created by traversing E.  */
+  if (!handle_dominating_asserts)
+    record_temporary_equivalences (e, const_and_copies, avail_exprs_stack);
+
   /* PHIs create temporary equivalences.
      Note that if we found a PHI that made the block non-threadable, then
      we need to bubble that up to our caller in the same manner we do