34 lines
1.1 KiB
JavaScript

// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --allow-natives-syntax
// This tests that NumberAdd passes on the right truncations
// even if it figures out during SimplifiedLowering that it
// can indeed do a Word32 operation (based on the feedback
// baked in for its inputs by other operators).
(function() {
// We need a + with Number feedback to get to a NumberAdd
// during the typed lowering pass of TurboFan's frontend.
function foo(x, y) { return x + y; }
foo(0.1, 0.2);
foo(0.1, 0.2);
// Now we need to fool TurboFan to think that it has to
// perform the `foo(x,-1)` on Float64 values until the
// very last moment (after the RETYPE phase of the
// SimplifiedLowering) where it realizes that the inputs
// and outputs of the NumberAdd allow it perform the
// operation on Word32.
function bar(x) {
x = Math.trunc(foo(x - 1, 1));
return foo(x, -1);
}
assertEquals(0, bar(1));
assertEquals(1, bar(2));
%OptimizeFunctionOnNextCall(bar);
assertEquals(2, bar(3));
})();