MIPS64: Fix random failures of fannkuch.js.

test/mjsunit/math-abs.js

 // Copyright 2010 the V8 project authors. All rights reserved.
 // 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
@@ skipping 102 matching lines @@
 // Regression test for SMI input of Math.abs on X64, see:
 // https://codereview.chromium.org/21180004/
 var a = [-1, -2];
 function foo2() {
   return Math.abs(a[0]);
 }
 assertEquals(1, foo2());
 assertEquals(1, foo2());
 %OptimizeFunctionOnNextCall(foo2);
 assertEquals(1, foo2());
+
+
+// Regression test for Integer input of Math.abs on mips64.
+function absHalf(bits) {
+  var x = 1 << (bits - 1);
+  var half = Math.abs(x);
+  return half;
+
+}
+
+// Create minimum integer input for abs() using bitwise operations
+// that sould overflow.

[Jakob Kummerow, 2015/06/19 14:50:25]

nit: s/sould/should/

+bits = 32;
+for (i = 0; i < 1000; i++) {

[Jakob Kummerow, 2015/06/19 14:50:25]

Please keep the testcase fast:

assertEquals(2147483648, absHalf(bits));
assertEquals(2147483648, absHalf(bits));
%OptimizeFunctionOnNextCall(absHalf);
assertEquals(2147483648, absHalf(bits));

+  assertEquals(2147483648, absHalf(bits));
+}