gc: fix &^=

Fixes #1394.

R=ken2
CC=golang-dev
https://golang.org/cl/3879041

diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 536c37701d74415445ade3f40d15cfeaa7e50779..fa3e5d5e4c31a87cdcab5d84a05cf2c2595c0073 100644 (file)
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -960,15 +960,15 @@ walkexpr(Node **np, NodeList **init)
                goto ret;
 
        case OASOP:
-               n->left = safeexpr(n->left, init);
-               walkexpr(&n->left, init);
-               l = n->left;
-               walkexpr(&n->right, init);
                if(n->etype == OANDNOT) {
                        n->etype = OAND;
                        n->right = nod(OCOM, n->right, N);
                        typecheck(&n->right, Erv);
                }
+               n->left = safeexpr(n->left, init);
+               walkexpr(&n->left, init);
+               l = n->left;
+               walkexpr(&n->right, init);
 
                /*
                 * on 32-bit arch, rewrite 64-bit ops into l = l op r.

diff --git a/test/fixedbugs/bug317.go b/test/fixedbugs/bug317.go
new file mode 100644 (file)
index 0000000..0cb26c2
--- /dev/null
+++ b/test/fixedbugs/bug317.go
@@ -0,0 +1,16 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out || echo BUG: bug317
+
+// Copyright 2011 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 main
+
+func main() {
+       x := []uint{0}
+       x[0] &^= f()
+}
+
+func f() uint {
+       return 1<<31 // doesn't panic with 1<<31 - 1
+}