fix crash in bug194; add bug196

R=ken
OCL=33694
CL=33697

src/cmd/gc/const.c

@@ -846,7 +846,7 @@ cmpslit(Node *l, Node *r)
 int
 smallintconst(Node *n)
 {
-	if(n->op == OLITERAL)
+	if(n->op == OLITERAL && n->type != T)
 	switch(simtype[n->type->etype]) {
 	case TINT8:
 	case TUINT8:
@@ -864,7 +864,7 @@ smallintconst(Node *n)
 long
 nonnegconst(Node *n)
 {
-	if(n->op == OLITERAL)
+	if(n->op == OLITERAL && n->type != T)
 	switch(simtype[n->type->etype]) {
 	case TINT8:
 	case TUINT8:

test/bugs/bug196.go

+// $G $D/$F.go && $L $F.$A && ./$A.out || echo BUG: bug196
+
+// 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
+
+var m = map[int]int{ 0: 0, 1: 0 }
+var nf = 0
+var i int
+
+func multi() (int, int) {
+	return 1,2
+}
+
+func xxx() {
+	var c chan int;
+	x, ok := <-c;
+
+	var m map[int]int;
+	x, ok = m[1];
+
+	var i interface{};
+	var xx int;
+	xx, ok = i.(int);
+
+	a,b := multi();
+}
+
+func f() map[int]int {
+	nf++;
+	return m;
+}
+
+func g() *int {
+	nf++;
+	return &i
+}
+
+func main() {
+	f()[0]++;
+	f()[1] += 2;
+	*g() %= 2;
+	if nf != 3 {
+		panicln("too many calls:", nf);
+	}
+
+}

test/golden.out

@@ -175,8 +175,13 @@ bugs/bug193.go:13: fatal error: optoas: no entry LSH-float
 errchk: bugs/bug193.go:14: missing expected error: 'shift'
 
 =========== bugs/bug194.go
+bugs/bug194.go:15: array index must be non-negative integer constant
 BUG should compile and run
-$RUNFILE: line 1: PID Segmentation fault      (core dumped) $G $D/$F.go
 
 =========== bugs/bug195.go
 bugs/bug195.go:9: BUG: errchk: compiler crashed
+
+=========== bugs/bug196.go
+too many calls: 5
+panic PC=xxx
+BUG: bug196