cmd/gc: fix codegen reordering for expressions involving && and ||

Fixes issue 2821.

R=rsc
CC=golang-dev
http://codereview.appspot.com/5606061

1 files changed, 25 insertions, 0 deletions

diff --git a/test/fixedbugs/bug406.go b/test/fixedbugs/bug406.go
new file mode 100644
index 000000000..9d755045b
--- /dev/null
+++ b/test/fixedbugs/bug406.go
@@ -0,0 +1,25 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out || echo "Bug406"
+
+// Copyright 2012 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.
+
+// Issue 2821
+package main
+
+type matrix struct {
+	e []int
+}
+
+func (a matrix) equal() bool {
+	for _ = range a.e {
+	}
+	return true
+}
+
+func main() {
+	var a matrix
+	var i interface{}
+	i = true && a.equal()
+	_ = i
+}