fix printing of -(1<<63)

R=r
OCL=15441
CL=15445
diff --git a/test/printbig.go b/test/printbig.go
new file mode 100644
index 0000000..5ec95b9
--- /dev/null
+++ b/test/printbig.go
@@ -0,0 +1,12 @@
+// $G $F.go && $L $F.$A && ./$A.out
+
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func main() {
+	print(-(1<<63), "\n");
+	print((1<<63)-1, "\n")
+}