--- ./libgo/go/runtime/lfstack_64bit.go	2017-04-12 15:20:31 -0500
+++ ./libgo/go/runtime/lfstack_64bit.go	2017-04-12 15:24:36 -0500
@@ -1,7 +1,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build amd64 arm64 mips64 mips64le ppc64 ppc64le s390x arm64be alpha mipsn64 sparc64
+// +build amd64 arm64 mips64 mips64le !aix,ppc64 ppc64le s390x arm64be alpha mipsn64 sparc64

 package runtime
 
--- ./libgo/go/runtime/aix_lfstack_64bit.go	2017-04-12 15:20:31 -0500
+++ ./libgo/go/runtime/aix_lfstack_64bit.go	2017-04-12 15:24:36 -0500
@@ -0,0 +1,35 @@
+// Copyright 2014 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.
+
+// +build aix,ppc64
+
+package runtime
+
+import "unsafe"
+
+const (
+	// addrBits is the number of bits needed to represent a virtual address.
+	//
+	// 64-bit processes use the range 0x0700000000000000-0x07FFFFFFFFFFFFFF
+        // for mmap on AIX.
+	//
+	// XXX we could substract 0x0700000000000000 from the address which
+        // XXX would leave us with 8 bits at the top and 3 bits at the bottom.
+        // XXX But this code is also used for addresses not allocated with mmap
+        // XXX starting with 0x0a00000000000000 which leaves us even less space!
+	addrBits = 60
+
+	// In addition to the 4 bits taken from the top, we can take 3 from the
+	// bottom, because node must be pointer-aligned, giving a total of 7 bits
+	// of count.
+	cntBits = 64 - addrBits + 3
+)
+
+func lfstackPack(node *lfnode, cnt uintptr) uint64 {
+	return uint64(uintptr(unsafe.Pointer(node)))<<(64-addrBits) | uint64(cnt&(1<<cntBits-1))
+}
+
+func lfstackUnpack(val uint64) *lfnode {
+	return (*lfnode)(unsafe.Pointer(uintptr(val >> cntBits << 3)))
+}
+