dart2js: Constant fold num.round()

tests/compiler/dart2js_extra/round_constant_folding_test.dart

+// Copyright (c) 2016, 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.
+
+import 'package:expect/expect.dart';
+
+const double PD1 = 0.0;
+const double PD2 = double.MIN_POSITIVE;
+const double PD3 = 2.0 * double.MIN_POSITIVE;
+const double PD4 = 1.18e-38;
+const double PD5 = 1.18e-38 * 2;
+const double PD6 = 0.49999999999999994;
+const double PD7 = 0.5;
+const double PD8 = 0.9999999999999999;
+const double PD9 = 1.0;
+const double PD10 = 1.000000000000001;
+const double PD11 = double.MAX_FINITE;
+
+const double ND1 = -PD1;
+const double ND2 = -PD2;
+const double ND3 = -PD3;
+const double ND4 = -PD4;
+const double ND5 = -PD5;
+const double ND6 = -PD6;
+const double ND7 = -PD7;
+const double ND8 = -PD8;
+const double ND9 = -PD9;
+const double ND10 = -PD10;
+const double ND11 = -PD11;
+
+const X1 = double.INFINITY;
+const X2 = double.NEGATIVE_INFINITY;
+const X3 = double.NAN;
+
+// The following numbers are on the border of 52 bits.
+// For example: 4503599627370499 + 0.5 => 4503599627370500.
+const PQ1 = 4503599627370496.0;
+const PQ2 = 4503599627370497.0;
+const PQ3 = 4503599627370498.0;
+const PQ4 = 4503599627370499.0;
+const PQ5 = 9007199254740991.0;
+const PQ6 = 9007199254740992.0;
+
+const NQ1 = -PQ1;
+const NQ2 = -PQ2;
+const NQ3 = -PQ3;
+const NQ4 = -PQ4;
+const NQ5 = -PQ5;
+const NQ6 = -PQ6;
+
+const int PI1 = 0;
+const int PI2 = 1;
+const int PI3 = 0x1234;
+const int PI4 = 0x12345678;
+const int PI5 = 0x123456789AB;
+const int PI6 = 0x123456789ABCDEF;
+const int PI7 = 0x123456789ABCDEF0123456789ABCDEF0123456789ABCDEF;
+
+const int NI1 = 0-PI1;
+const int NI2 = -PI2;
+const int NI3 = -PI3;
+const int NI4 = -PI4;
+const int NI5 = -PI5;
+const int NI6 = -PI6;
+const int NI7 = -PI7;
+
+
+/// Ensures that the behaviour of `action()` is the same as `value.round()`.
+@NoInline()  // To ensure 'value.round()' has a non-constant receiver.
+check(value, action) {
+  var result1, result2;
+  try {
+    result1 = value.round();
+  } catch (e) {
+    result1 = e;
+  }
+
+  try {
+    result2 = action();
+  } catch (e) {
+    result2 = e;
+  }
+
+  Expect.equals(result1.runtimeType, result2.runtimeType);
+  if (result1 is num) {
+    Expect.equals(result1, result2);
+    Expect.equals(result1 is int, result2 is int);
+  } else {
+    Expect.equals(result1.runtimeType, result2.runtimeType);
+    Expect.isTrue(result1 is Error);
+  }
+}
+
+@NoInline()
+void unusedCall(num x) {
+  x.round(); // This call should not be removed since it might throw.
+}
+
+main() {
+  check(PD1, () => PD1.round());
+  check(PD2, () => PD2.round());
+  check(PD3, () => PD3.round());
+  check(PD4, () => PD4.round());
+  check(PD5, () => PD5.round());
+  check(PD6, () => PD6.round());
+  check(PD7, () => PD7.round());
+  check(PD8, () => PD8.round());
+  check(PD9, () => PD9.round());
+  check(PD10, () => PD10.round());
+  check(PD11, () => PD11.round());
+
+  check(ND1, () => ND1.round());
+  check(ND2, () => ND2.round());
+  check(ND3, () => ND3.round());
+  check(ND4, () => ND4.round());
+  check(ND5, () => ND5.round());
+  check(ND6, () => ND6.round());
+  check(ND7, () => ND7.round());
+  check(ND8, () => ND8.round());
+  check(ND9, () => ND9.round());
+  check(ND10, () => ND10.round());
+  check(ND11, () => ND11.round());
+
+  check(X1, () => X1.round());
+  check(X2, () => X2.round());
+  check(X3, () => X3.round());
+
+  check(PQ1, () => PQ1.round());
+  check(PQ2, () => PQ2.round());
+  check(PQ3, () => PQ3.round());
+  check(PQ4, () => PQ4.round());
+  check(PQ5, () => PQ5.round());
+  check(PQ6, () => PQ6.round());
+
+  check(NQ1, () => NQ1.round());
+  check(NQ2, () => NQ2.round());
+  check(NQ3, () => NQ3.round());
+  check(NQ4, () => NQ4.round());
+  check(NQ5, () => NQ5.round());
+  check(NQ6, () => NQ6.round());
+
+  check(PI1, () => PI1.round());
+  check(PI2, () => PI2.round());
+  check(PI3, () => PI3.round());
+  check(PI4, () => PI4.round());
+  check(PI5, () => PI5.round());
+  check(PI6, () => PI6.round());
+  check(PI7, () => PI7.round());
+
+  check(NI1, () => NI1.round());
+  check(NI2, () => NI2.round());
+  check(NI3, () => NI3.round());
+  check(NI4, () => NI4.round());
+  check(NI5, () => NI5.round());
+  check(NI6, () => NI6.round());
+  check(NI7, () => NI7.round());
+
+  // Check that the operation is not removed if it can throw, even if the result
+  // is unused.
+  Expect.throws(() { X1.round(); });
+  Expect.throws(() { X2.round(); });
+  Expect.throws(() { X3.round(); });
+  unusedCall(0);
+  Expect.throws(() { unusedCall(X1); });
+  Expect.throws(() { unusedCall(X2); });
+  Expect.throws(() { unusedCall(X3); });
+}