[turbofan] Transform x * -1.0 to -0.0 - x.

test/mjsunit/asm/float64mul.js

+// Copyright 2014 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.
+
+function Module(stdlib, foreign, heap) {
+  "use asm";
+  function f1(i) {
+    i = +i;
+    return +(i * -1);
+  }
+  function f2(i) {
+    i = +i;
+    return +(-1 * i);
+  }
+  return { f1: f1, f2: f2 };
+}
+
+var m = Module(this, {}, new ArrayBuffer(64 * 1024));
+
+for (var i = -2147483648; i < 2147483648; i += 3999777) {
+  assertEquals(-i, m.f1(i));
+  assertEquals(-i, m.f2(i));
+}

[Jarin, 2014/11/06 06:07:49]

Could we possibly test the corner cases, such as -0, infinities and such?

[Benedikt Meurer, 2014/11/06 06:12:47]

Done.