[turbofan] Optimize division/modulus by constant.

test/mjsunit/asm/int32div.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.
+
+var stdlib = {};
+var foreign = {};
+var heap = new ArrayBuffer(64 * 1024);
+
+function Int32Div(divisor) {
+  var name = "div_";
+  if (divisor < 0) {
+    name += "minus_";
+  }
+  name += Math.abs(divisor);
+  var m = eval("function Module(stdlib, foreign, heap) {\n"
+      + " \"use asm\";\n"
+      + " function " + name + "(dividend) {\n"
+      + "  return ((dividend | 0) / " + divisor + ") | 0;\n"
+      + " }\n"
+      + " return { f: " + name + "}\n"
+      + "}; Module");
+  return m(stdlib, foreign, heap).f;
+}
+
+var divisors = [-2147483648, -32 * 1024, -1000, -16, -7, -2, -1, 0,
+                1, 3, 4, 10, 64, 100, 1024, 2147483647];
+for (var i in divisors) {
+  var divisor = divisors[i];
+  var div = Int32Div(divisor);
+  for (var dividend = -2147483648; dividend < 2147483648; dividend += 3999773) {
+    assertEquals((dividend / divisor) | 0, div(dividend));
+  }
+}