cmd/compile: fix -race nit

Fixes #13264.

Change-Id: I74b941164610921a03814733fea08631f18b6178
Reviewed-on: https://go-review.googlesource.com/17815Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/compile/internal/gc/racewalk.go

@@ -151,7 +151,7 @@ func instrumentnode(np **Node, init **NodeList, wr int, skip int) {
 		for l := n.List; l != nil; l = l.Next {
 			switch l.N.Op {
 			case OCALLFUNC, OCALLMETH, OCALLINTER:
-				instrumentnode(&l.N, &out, 0, 0)
+				instrumentnode(&l.N, &l.N.Ninit, 0, 0)
 				out = list(out, l.N)
 				// Scan past OAS nodes copying results off stack.
 				// Those must not be instrumented, because the

src/runtime/race/testdata/issue13264_test.go

+// Copyright 2015 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 race_test
+
+// golang.org/issue/13264
+// The test is that this compiles at all.
+
+func issue13264() {
+	for ; ; []map[int]int{}[0][0] = 0 {
+	}
+}