compiler: implement array equality

Implement binops == and != on array types.

compiler/compiler.go

@@ -2867,6 +2867,30 @@ func (c *Compiler) parseBinOp(op token.Token, typ types.Type, x, y llvm.Value) (
 		default:
 			return llvm.Value{}, errors.New("todo: binop on slice: " + op.String())
 		}
+	case *types.Array:
+		// Compare each array element and combine the result. From the spec:
+		//     Array values are comparable if values of the array element type
+		//     are comparable. Two array values are equal if their corresponding
+		//     elements are equal.
+		result := llvm.ConstInt(c.ctx.Int1Type(), 1, true)
+		for i := 0; i < int(typ.Len()); i++ {
+			xField := c.builder.CreateExtractValue(x, i, "")
+			yField := c.builder.CreateExtractValue(y, i, "")
+			fieldEqual, err := c.parseBinOp(token.EQL, typ.Elem(), xField, yField)
+			if err != nil {
+				return llvm.Value{}, err
+			}
+			result = c.builder.CreateAnd(result, fieldEqual, "")
+		}
+		switch op {
+		case token.EQL: // ==
+			return result, nil
+		case token.NEQ: // !=
+			return c.builder.CreateNot(result, ""), nil
+		default:
+			return llvm.Value{}, errors.New("unknown: binop on struct: " + op.String())
+		}
+		return result, nil
 	case *types.Struct:
 		// Compare each struct field and combine the result. From the spec:
 		//     Struct values are comparable if all their fields are comparable.

testdata/binop.go

@@ -24,6 +24,14 @@ func main() {
 	println("ab" < "aa")
 	println("aa" < "ab")
 
+	println("array equality")
+	println(a1 == [2]int{1, 2})
+	println(a1 != [2]int{1, 2})
+	println(a1 == [2]int{1, 3})
+	println(a1 == [2]int{2, 2})
+	println(a1 == [2]int{2, 1})
+	println(a1 != [2]int{2, 1})
+
 	println("struct equality")
 	println(s1 == Struct1{3, true})
 	println(s1 == Struct1{4, true})
@@ -48,6 +56,8 @@ var a = "a"
 var s1 = Struct1{3, true}
 var s2 = Struct2{"foo", 0.0, 5}
 
+var a1 = [2]int{1, 2}
+
 type Struct1 struct {
 	i int
 	b bool

testdata/binop.txt

@@ -20,6 +20,13 @@ true
 false
 false
 true
+array equality
+true
+false
+false
+false
+false
+true
 struct equality
 true
 false