dart2js js_runtime: faster code for floor() & ceil()

tests/compiler/dart2js_extra/truncation_errors_test.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Check that exception messages for truncating operations contains the
+// operands.
+
+import 'package:expect/expect.dart';
+
+@NoInline() @AssumeDynamic()
+confuse(x) => x;
+
+void find1(expected, thunk) {
+  if (thunk == null) return;
+  var returned, exceptionText;
+  try {
+    returned = thunk();
+  } catch (e) {
+    exceptionText = '$e';
+  }
+  if (exceptionText == null) {
+    Expect.fail(
+        'Expected exception containing "$expected", returned: $returned');
+  }
+  Expect.isTrue(
+      exceptionText.contains(expected),
+      'Expected "$expected" in "$exceptionText"');
+}
+
+void find(expected, [thunk1, thunk2, thunk3, thunk4]) {
+  find1(expected, thunk1);
+  find1(expected, thunk2);
+  find1(expected, thunk3);
+  find1(expected, thunk4);
+}
+
+main() {
+
+  var NaN = double.NAN;
+  var Infinity = double.INFINITY;
+
+  find(' Infinity: 123 ~/ 0',
+       () => confuse(123) ~/ confuse(0),
+       () => confuse(123) ~/ 0,
+       () => 123 ~/ confuse(0),
+       () => 123 ~/ 0);
+
+  find('-Infinity: 123 ~/ -0.0',
+       () => confuse(123) ~/ confuse(-0.0),
+       () => confuse(123) ~/ -0.0,
+       () => 123 ~/ confuse(-0.0),
+       () => 123 ~/ -0.0);
+
+  find(' NaN: NaN ~/ 123',
+       () => confuse(NaN) ~/ confuse(123),
+       () => confuse(NaN) ~/ 123,
+       () => NaN ~/ confuse(123),
+       () => NaN ~/ 123);
+
+  find(' Infinity: 1e+200 ~/ 1e-200',
+       () => confuse(1e200) ~/ confuse(1e-200),
+       () => confuse(1e200) ~/ 1e-200,
+       () => 1e200 ~/ confuse(1e-200),
+       () => 1e200 ~/ 1e-200);
+
+  find('NaN.toInt()',
+       () => confuse(NaN).toInt(),
+       () => NaN.toInt());
+  find(' Infinity.toInt()',
+       () => confuse(Infinity).toInt(),
+       () => Infinity.toInt());
+  find('-Infinity.toInt()',
+       () => confuse(-Infinity).toInt(),
+       () => (-Infinity).toInt());
+
+  find('NaN.ceil()',
+       () => confuse(NaN).ceil(),
+       () => NaN.ceil());
+  find(' Infinity.ceil()',
+       () => confuse(Infinity).ceil(),
+       () => Infinity.ceil());
+  find('-Infinity.ceil()',
+       () => confuse(-Infinity).ceil(),
+       () => (-Infinity).ceil());
+
+  find('NaN.floor()',
+       () => confuse(NaN).floor(),
+       () => NaN.floor());
+  find(' Infinity.floor()',
+       () => confuse(Infinity).floor(),
+       () => Infinity.floor());
+  find('-Infinity.floor()',
+       () => confuse(-Infinity).floor(),
+       () => (-Infinity).floor());
+
+  find('NaN.round()',
+       () => confuse(NaN).round(),
+       () => NaN.round());
+  find(' Infinity.round()',
+       () => confuse(Infinity).round(),
+       () => Infinity.round());
+  find('-Infinity.round()',
+       () => confuse(-Infinity).round(),
+       () => (-Infinity).round());
+
+  // `truncate()` is the same as `toInt()`.
+  // We could change the runtime so that `truncate` is reported.
+  find('NaN.toInt()',
+       () => confuse(NaN).truncate(),
+       () => NaN.truncate());
+  find(' Infinity.toInt()',
+       () => confuse(Infinity).truncate(),
+       () => Infinity.truncate());
+  find('-Infinity.toInt()',
+       () => confuse(-Infinity).truncate(),
+       () => (-Infinity).truncate());
+
+}
+