tighten invariants of HValue::InferRange

test/mjsunit/math-round.js

-// Copyright 2010 the V8 project authors. All rights reserved.
+// Copyright 2010, 2011 the V8 project authors. All rights reserved.

[Kevin Millikin (Chromium), 2011/08/02 10:24:14]

We just update the copyright date to 2011, not a range of dates.

 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
@@ skipping 25 matching lines @@
   %OptimizeFunctionOnNextCall(doRound);
   assertEquals(expect, doRound(input));
 }
 
 testRound(0, 0);
 testRound(-0, -0);
 testRound(Infinity, Infinity);
 testRound(-Infinity, -Infinity);
 testRound(NaN, NaN);
 
+// Ensure that a negative zero coming from Math.round is properly
+// handled by other ops that take unboxed doubles.  See cr7514040.
+function roundsum(i,n) {
+  var ret = Math.round(n);
+  while (--i > 0) {
+    ret += Math.round(n);
+  }
+  return ret;
+}
+assertEquals(-0, roundsum(1000,-0));
+%OptimizeFunctionOnNextCall(roundsum);
+// It seems that %OptimizeFunctionOnNextCall doesn't always work!  Here
+// we push iterations up to a large number to ensure that we try to
+// unbox doubles as much as possible.
+assertEquals(-0, roundsum(1000000,-0));
+
 testRound(1, 0.5);
 testRound(1, 0.7);
 testRound(1, 1);
 testRound(1, 1.1);
 testRound(1, 1.49999);
 testRound(-0, -0.5);
 testRound(-1, -0.5000000000000001);
 testRound(-1, -0.7);
 testRound(-1, -1);
 testRound(-1, -1.1);
@@ skipping 91 matching lines @@
 testRound(-Math.pow(2,52)+1, -max_fraction);
 testRound(-min_nonfraction, -min_nonfraction);
 testRound(-max_non_infinite, -max_non_infinite);
 
 testRound(min_smi31, min_smi31 - 0.5);
 testRound(min_smi31 + 1, min_smi31 + 0.5);
 testRound(min_smi32, min_smi32 - 0.5);
 testRound(min_smi32 + 1, min_smi32 + 0.5);