Improve jump thread dumping

[Jeff Law <law at redhat dot com>]

This finishes passing the entire path of a jump threading opportunity to 
register_jump_thread and arranges to dump the entire path when dumping 
details.

Bootstrapped and regression tested on x86_64-unknown-linux-gnu. 
Installed onto the trunk.



diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f798068..0adc930 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2013-09-03  Jeff Law  <law@redhat.com>
+
+	* tree-ssa-threadedge.c (thread_across_edge): Record entire path
+	when not threading through a joiner block.  Pass joiner/no joiner
+	state to register_jump_thread.
+	* tree-ssa-threadupdate.c (register_jump_thread): Get joiner/no joiner
+	state from argument rather than implying on path length.
+	Dump the entire jump thread path into debugging dump.
+	* tree-flow.h (register_jump_thread): Update prototype.
+
 2013-08-29  Xinliang David Li  <davidxl@google.com>
 
 	* tree-vect-data-refs.c (vect_compute_data_ref_alignment):
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8712a19..dbc88b1 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2013-09-03  Jeff Law  <law@redhat.com>
+
+	* tree-ssa/ssa-dom-thread-3.c: Update due to changes in debug
+	dump output.
+
 2013-09-03  Meador Inge  <meadori@codesourcery.com>
 
 	Revert:
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-3.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-3.c
index d67f869..c2efd15 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-3.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-3.c
@@ -43,6 +43,5 @@ expand_one_var (tree var, unsigned char toplevel, unsigned char really_expand)
 }
 /* We should thread the jump, through an intermediate block.  */
 /* { dg-final { scan-tree-dump-times "Threaded" 1 "dom1"} } */
-/* { dg-final { scan-tree-dump-times "one or more intermediate" 1 "dom1"} } */
-/* { dg-final { cleanup-tree-dump "dom1" } } */
+/* { dg-final { scan-tree-dump-times "Registering jump thread .through joiner block.: \\(.*\\);  \\(.*\\);  \\(.*\\);" 1 "dom1"} } */
 
diff --git a/gcc/tree-flow.h b/gcc/tree-flow.h
index ab42470..333e168 100644
--- a/gcc/tree-flow.h
+++ b/gcc/tree-flow.h
@@ -749,7 +749,7 @@ bool may_be_nonaddressable_p (tree expr);
 
 /* In tree-ssa-threadupdate.c.  */
 extern bool thread_through_all_blocks (bool);
-extern void register_jump_thread (vec<edge>);
+extern void register_jump_thread (vec<edge>, bool);
 
 /* In gimplify.c  */
 tree force_gimple_operand_1 (tree, gimple_seq *, gimple_predicate, tree);
diff --git a/gcc/tree-ssa-threadedge.c b/gcc/tree-ssa-threadedge.c
index fc33647..dddcfce 100644
--- a/gcc/tree-ssa-threadedge.c
+++ b/gcc/tree-ssa-threadedge.c
@@ -901,6 +901,10 @@ thread_across_edge (gimple dummy_cond,
 	  if (dest == e->dest)
 	    goto fail;
 
+	  vec<edge> path = vNULL;
+	  path.safe_push (e);
+	  path.safe_push (taken_edge);
+
 	  /* DEST could be null for a computed jump to an absolute
 	     address.  If DEST is not null, then see if we can thread
 	     through it as well, this helps capture secondary effects
@@ -922,7 +926,10 @@ thread_across_edge (gimple dummy_cond,
 						  simplify,
 						  visited);
 		  if (e2)
-		    taken_edge = e2;
+		    {
+		      taken_edge = e2;
+		      path.safe_push (e2);
+		    }
 		}
 	      while (e2);
 	      BITMAP_FREE (visited);
@@ -931,13 +938,10 @@ thread_across_edge (gimple dummy_cond,
 	  remove_temporary_equivalences (stack);
 	  if (taken_edge)
 	    {
-	      vec<edge> path = vNULL;
 	      propagate_threaded_block_debug_into (taken_edge->dest, e->dest);
-	      path.safe_push (e);
-	      path.safe_push (taken_edge);
-	      register_jump_thread (path);
-	      path.release ();
+	      register_jump_thread (path, false);
 	    }
+	  path.release ();
 	  return;
 	}
     }
@@ -1009,7 +1013,7 @@ thread_across_edge (gimple dummy_cond,
 	      {
 		propagate_threaded_block_debug_into (e3->dest,
 						     taken_edge->dest);
-		register_jump_thread (path);
+		register_jump_thread (path, true);
 	      }
 	  }
 
diff --git a/gcc/tree-ssa-threadupdate.c b/gcc/tree-ssa-threadupdate.c
index 8a872a3..8e40f66 100644
--- a/gcc/tree-ssa-threadupdate.c
+++ b/gcc/tree-ssa-threadupdate.c
@@ -1303,7 +1303,7 @@ thread_through_all_blocks (bool may_peel_loop_headers)
    after fixing the SSA graph.  */
 
 void
-register_jump_thread (vec<edge> path)
+register_jump_thread (vec<edge> path, bool through_joiner)
 {
   /* Convert PATH into 3 edge representation we've been using.  This
      is temporary until we convert this file to use a path representation
@@ -1312,7 +1312,7 @@ register_jump_thread (vec<edge> path)
   edge e2 = path[1];
   edge e3;
 
-  if (path.length () <= 2)
+  if (!through_joiner)
     e3 = NULL;
   else
     e3 = path[path.length () - 1];
@@ -1322,14 +1322,23 @@ register_jump_thread (vec<edge> path)
   if (e2 == NULL)
     return;
 
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      unsigned int i;
+
+      fprintf (dump_file,
+	       "  Registering jump thread %s:",
+	       through_joiner ? "(through joiner block)" : "");
+
+      for (i = 0; i < path.length (); i++)
+	fprintf (dump_file, " (%d, %d); ",
+		 path[i]->src->index, path[i]->dest->index);
+      fputc ('\n', dump_file);
+    }
+    
   if (!threaded_edges.exists ())
     threaded_edges.create (15);
 
-  if (dump_file && (dump_flags & TDF_DETAILS)
-      && e->dest != e2->src)
-    fprintf (dump_file,
-	     "  Registering jump thread around one or more intermediate blocks\n");
-
   threaded_edges.safe_push (e);
   threaded_edges.safe_push (e2);
   threaded_edges.safe_push (e3);