diff --git a/src/cmd/compile/internal/ssa/regalloc.go b/src/cmd/compile/internal/ssa/regalloc.go
index b6fae5e0a3e4e..8abbf615076fb 100644
--- a/src/cmd/compile/internal/ssa/regalloc.go
+++ b/src/cmd/compile/internal/ssa/regalloc.go
@@ -1455,7 +1455,7 @@ func (s *regAllocState) regalloc(f *Func) {
 						}
 					}
 					// Avoid registers we're saving for other values.
-					if mask&^desired.avoid != 0 {
+					if mask&^desired.avoid&^s.nospill != 0 {
 						mask &^= desired.avoid
 					}
 					r := s.allocReg(mask, v)
diff --git a/test/fixedbugs/issue33355.go b/test/fixedbugs/issue33355.go
new file mode 100644
index 0000000000000..c4b1e2e1a23ba
--- /dev/null
+++ b/test/fixedbugs/issue33355.go
@@ -0,0 +1,147 @@
+// compile
+
+// Copyright 2019 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.
+
+// This code failed on arm64 in the register allocator.
+// See issue 33355.
+
+package server
+
+import (
+	"bytes"
+	"sync"
+)
+
+type client struct {
+	junk [4]int
+	mu   sync.Mutex
+	srv  *Server
+	gw   *gateway
+	msgb [100]byte
+}
+
+type gateway struct {
+	cfg    *gatewayCfg
+	outsim *sync.Map
+}
+
+type gatewayCfg struct {
+	replyPfx []byte
+}
+
+type Account struct {
+	Name string
+}
+
+type Server struct {
+	gateway *srvGateway
+}
+
+type srvGateway struct {
+	outo     []*client
+}
+
+type subscription struct {
+	queue   []byte
+	client  *client
+}
+
+type outsie struct {
+	ni    map[string]struct{}
+	sl    *Sublist
+	qsubs int
+}
+
+type Sublist struct {
+}
+
+type SublistResult struct {
+	psubs []*subscription
+	qsubs [][]*subscription
+}
+
+var subPool = &sync.Pool{}
+
+func (c *client) sendMsgToGateways(acc *Account, msg, subject, reply []byte, qgroups [][]byte) {
+	var gws []*client
+	gw := c.srv.gateway
+	for i := 0; i < len(gw.outo); i++ {
+		gws = append(gws, gw.outo[i])
+	}
+	var (
+		subj       = string(subject)
+		queuesa    = [512]byte{}
+		queues     = queuesa[:0]
+		mreply     []byte
+		dstPfx     []byte
+		checkReply = len(reply) > 0
+	)
+
+	sub := subPool.Get().(*subscription)
+
+	if subjectStartsWithGatewayReplyPrefix(subject) {
+		dstPfx = subject[:8]
+	}
+	for i := 0; i < len(gws); i++ {
+		gwc := gws[i]
+		if dstPfx != nil {
+			gwc.mu.Lock()
+			ok := bytes.Equal(dstPfx, gwc.gw.cfg.replyPfx)
+			gwc.mu.Unlock()
+			if !ok {
+				continue
+			}
+		} else {
+			qr := gwc.gatewayInterest(acc.Name, subj)
+			queues = queuesa[:0]
+			for i := 0; i < len(qr.qsubs); i++ {
+				qsubs := qr.qsubs[i]
+				queue := qsubs[0].queue
+				add := true
+				for _, qn := range qgroups {
+					if bytes.Equal(queue, qn) {
+						add = false
+						break
+					}
+				}
+				if add {
+					qgroups = append(qgroups, queue)
+				}
+			}
+			if len(queues) == 0 {
+				continue
+			}
+		}
+		if checkReply {
+			checkReply = false
+			mreply = reply
+		}
+		mh := c.msgb[:10]
+		mh = append(mh, subject...)
+		if len(queues) > 0 {
+			mh = append(mh, mreply...)
+			mh = append(mh, queues...)
+		}
+		sub.client = gwc
+	}
+	subPool.Put(sub)
+}
+
+func subjectStartsWithGatewayReplyPrefix(subj []byte) bool {
+	return len(subj) > 8 && string(subj[:4]) == "foob"
+}
+
+func (c *client) gatewayInterest(acc, subj string) *SublistResult {
+	ei, _ := c.gw.outsim.Load(acc)
+	var r *SublistResult
+	e := ei.(*outsie)
+	r = e.sl.Match(subj)
+	return r
+}
+
+func (s *Sublist) Match(subject string) *SublistResult {
+	return nil
+}
+