gc: function argument ordering bug

Fixes #370.

R=ken2
https://golang.org/cl/163097

diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 62bbf9f5abea731c4bb0906ab41f02e2802295ce..771c258d0cafaaf87f837fce9a9667843495ba58 100644 (file)
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -1875,7 +1875,7 @@ reorder1(NodeList *all)
 {
        Node *f, *a, *n;
        NodeList *l, *r, *g;
-       int c, t;
+       int c, d, t;
 
        c = 0;  // function calls
        t = 0;  // total parameters
@@ -1891,17 +1891,17 @@ reorder1(NodeList *all)
                return all;
 
        g = nil;        // fncalls assigned to tempnames
-       f = N;  // one fncall assigned to stack
+       f = N;  // last fncall assigned to stack
        r = nil;        // non fncalls and tempnames assigned to stack
-
+       d = 0;
        for(l=all; l; l=l->next) {
                n = l->n;
-               ullmancalc(n);
                if(n->ullman < UINF) {
                        r = list(r, n);
                        continue;
                }
-               if(f == N) {
+               d++;
+               if(d == c) {
                        f = n;
                        continue;
                }

diff --git a/test/fixedbugs/bug221.go b/test/fixedbugs/bug221.go
new file mode 100644 (file)
index 0000000..39255d6
--- /dev/null
+++ b/test/fixedbugs/bug221.go
@@ -0,0 +1,38 @@
+// $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.
+
+// function call arg reordering was picking out 1 call that
+// didn't need to be in a temporary, but it was picking
+// out the first call instead of the last call.
+// http://code.google.com/p/go/issues/detail?id=370
+
+package main
+
+var gen = 'a'
+func f(n int) string {
+       s := string(gen) + string(n+'A'-1);
+       gen++;
+       return s;
+}
+
+func g(x, y string) string {
+       return x + y
+}
+
+func main() {
+       s := f(1) + f(2);
+       if s != "aAbB" {
+               panic("BUG: bug221a: ", s);
+       }
+       s = g(f(3), f(4));
+       if s != "cCdD" {
+               panic("BUG: bug221b: ", s);
+       }
+       s = f(5) + f(6) + f(7) + f(8) + f(9);
+       if s != "eEfFgGhHiI" {
+               panic("BUG: bug221c: ", s);
+       }
+}