test: add bug494: test case miscompiled by gccgo

Gccgo incorrectly executed functions multiple times when they appeared
in a composite literal that required a conversion between different
interface types.

Change-Id: I7b40e76ed23fa8440ffa03b262041265c109adf7
Reviewed-on: https://go-review.googlesource.com/1710
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>

diff --git a/test/fixedbugs/bug494.go b/test/fixedbugs/bug494.go
new file mode 100644 (file)
index 0000000..42f1879
--- /dev/null
+++ b/test/fixedbugs/bug494.go
@@ -0,0 +1,51 @@
+// run
+
+// 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.
+
+// Gccgo incorrectly executed functions multiple times when they
+// appeared in a composite literal that required a conversion between
+// different interface types.
+
+package main
+
+type MyInt int
+
+var c MyInt
+
+func (c *MyInt) S(i int) {
+       *c = MyInt(i)
+}
+
+func (c *MyInt) V() int {
+       return int(*c)
+}
+
+type i1 interface {
+       S(int)
+       V() int
+}
+
+type i2 interface {
+       V() int
+}
+
+type s struct {
+       i i2
+}
+
+func f() i1 {
+       c++
+       return &c
+}
+
+func main() {
+       p := &s{f()}
+       if v := p.i.V(); v != 1 {
+               panic(v)
+       }
+       if c != 1 {
+               panic(c)
+       }
+}