gc: another shift bug

rsc · rsc · commit 603f9feeeccc · 2010-12-13T13:42:51.000-05:00
Fixes golang#1316. R=ken2 CC=golang-dev https://golang.org/cl/3575042
diff --git a/src/cmd/gc/const.c b/src/cmd/gc/const.c
@@ -101,7 +101,7 @@ convlit1(Node **np, Type *t, int explicit)
 		break;
 	case OLSH:
 	case ORSH:
-		convlit1(&n->left, t, explicit);
+		convlit1(&n->left, t, explicit && isideal(n->left->type));
 		t = n->left->type;
 		if(t != T && !isint[t->etype]) {
 			yyerror("invalid operation: %#N (shift of type %T)", n, t);
diff --git a/test/const3.go b/test/const3.go
@@ -26,4 +26,10 @@ func main() {
 		println("type info didn't propagate in const: got", s)
 		panic("fail")
 	}
+	x := uint(5)
+	y := float64(uint64(1)<<x)	// used to fail to compile
+	if y != 32 {
+		println("wrong y", y)
+		panic("fail")
+	}
 }

Original file line number	Diff line number	Diff line change
`@@ -26,4 +26,10 @@ func main() {`
`26`	`26`	`println("type info didn't propagate in const: got", s)`
`27`	`27`	`panic("fail")`
`28`	`28`	`}`
	`29`	`+ x := uint(5)`
	`30`	`+ y := float64(uint64(1)<<x) // used to fail to compile`
	`31`	`+ if y != 32 {`
	`32`	`+ println("wrong y", y)`
	`33`	`+ panic("fail")`
	`34`	`+ }`
`29`	`35`	`}`