cmd/compile: remove Node.Nincr, Node.Nelse, Node.Initplan

$ sizeof -p cmd/compile/internal/gc Node
Node 288
$

Change-Id: I4e316efa246132b3faa3a892e4fe9c9039250665
Reviewed-on: https://go-review.googlesource.com/10520
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
diff --git a/src/cmd/compile/internal/gc/racewalk.go b/src/cmd/compile/internal/gc/racewalk.go
index 05a902e..e35054c 100644
--- a/src/cmd/compile/internal/gc/racewalk.go
+++ b/src/cmd/compile/internal/gc/racewalk.go
@@ -372,8 +372,13 @@
 		goto ret
 
 		// just do generic traversal
-	case OFOR,
-		OIF,
+	case OFOR:
+		if n.Right != nil {
+			racewalknode(&n.Right, &n.Right.Ninit, 0, 0)
+		}
+		goto ret
+
+	case OIF,
 		OCALLMETH,
 		ORETURN,
 		ORETJMP,
@@ -413,11 +418,7 @@
 	if n.Ntest != nil {
 		racewalknode(&n.Ntest, &n.Ntest.Ninit, 0, 0)
 	}
-	if n.Nincr != nil {
-		racewalknode(&n.Nincr, &n.Nincr.Ninit, 0, 0)
-	}
 	racewalklist(n.Nbody, nil)
-	racewalklist(n.Nelse, nil)
 	racewalklist(n.Rlist, nil)
 	*np = n
 }
@@ -577,9 +578,7 @@
 	foreachnode(n.Right, f, c)
 	foreachlist(n.List, f, c)
 	foreachnode(n.Ntest, f, c)
-	foreachnode(n.Nincr, f, c)
 	foreachlist(n.Nbody, f, c)
-	foreachlist(n.Nelse, f, c)
 	foreachlist(n.Rlist, f, c)
 }