bug185 - return b,a from func() (a,b int)

R=ken
OCL=32900
CL=32900

diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 90196ad7d60e3fa1d89c1b8529796e9d98ae1481..0d9f7f520e92be0af8cecf6db7870ec30cd24e4d 100644 (file)
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -247,12 +247,22 @@ walkstmtlist(NodeList *l)
                walkstmt(&l->n);
 }
 
+static int
+samelist(NodeList *a, NodeList *b)
+{
+       for(; a && b; a=a->next, b=b->next)
+               if(a->n != b->n)
+                       return 0;
+       return a == b;
+}
+
+
 void
 walkstmt(Node **np)
 {
        NodeList *init;
-       NodeList *ll;
-       int lno;
+       NodeList *ll, *rl;
+       int cl, lno;
        Node *n;
 
        n = *np;
@@ -350,8 +360,28 @@ walkstmt(Node **np)
 
        case ORETURN:
                walkexprlist(n->list, &n->ninit);
-               if(curfn->type->outnamed && n->list == nil) {
-                       // print("special return\n");
+               if(curfn->type->outnamed && count(n->list) != 1) {
+                       if(n->list == nil) {
+                               // print("special return\n");
+                               break;
+                       }
+                       // assign to the function out parameters,
+                       // so that reorder3 can fix up conflicts
+                       rl = nil;
+                       for(ll=curfn->dcl; ll != nil; ll=ll->next) {
+                               cl = ll->n->class & ~PHEAP;
+                               if(cl == PAUTO)
+                                       break;
+                               if(cl == PPARAMOUT)
+                                       rl = list(rl, ll->n);
+                       }
+                       if(samelist(rl, n->list)) {
+                               // special return in disguise
+                               n->list = nil;
+                               break;
+                       }
+                       ll = ascompatee(n->op, rl, n->list, &n->ninit);
+                       n->list = reorder3(ll);
                        break;
                }
                ll = ascompatte(n->op, getoutarg(curfn->type), n->list, 1, &n->ninit);

diff --git a/test/fixedbugs/bug185.go b/test/fixedbugs/bug185.go
new file mode 100644 (file)
index 0000000..7f4bcb2
--- /dev/null
+++ b/test/fixedbugs/bug185.go
@@ -0,0 +1,33 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// Copyright 2009 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 g() { }
+
+func f1() (a, b int) {
+       a, b = 2, 1;
+       g();    // defeat optimizer
+       return a, b;
+}
+
+func f2() (a, b int) {
+       a, b = 1, 2;
+       g();    // defeat optimizer
+       return b, a;
+}
+
+func main() {
+       x, y := f1();
+       if x != 2 || y != 1 {
+               panicln("f1", x, y);
+       }
+
+       x, y = f2();
+       if x != 2 || y != 1 {
+               panicln("f2", x, y);
+       }
+}