[turbofan] Implement OSR for outer loops.

test/mjsunit/compiler/osr-multiple3.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.
+
+// Flags: --use-osr
+// TODO(titzer): enable --turbo-osr when nested OSR works.
+
+function f1(a,b,c) {
+  var x = 0;
+  var y = 0;
+  var z = 0;
+  for (var i = 0; i < 2; i++) {
+    for (var j = 0; j < 2; j++) {
+      while (a > 0) { x += 19; a--; }
+      while (b > 0) { y += 23; b--; }
+      while (c > 0) { z += 29; c--; }
+    }
+  }
+  return x + y + z;
+}
+
+function f2(a,b,c) {
+  var x = 0;
+  var y = 0;
+  var z = 0;
+  for (var i = 0; i < 2; i++) {
+    for (var j = 0; j < 2; j++) {
+      while (a > 0) { x += 19; a--; }
+      while (b > 0) { y += 23; b--; }
+      while (c > 0) { z += 29; c--; }
+    }
+  }
+  return x + y + z;
+}
+
+
+function f3(a,b,c) {
+  var x = 0;
+  var y = 0;
+  var z = 0;
+  for (var i = 0; i < 2; i++) {
+    for (var j = 0; j < 2; j++) {
+      while (a > 0) { x += 19; a--; }
+      while (b > 0) { y += 23; b--; }
+      while (c > 0) { z += 29; c--; }
+    }
+  }
+  return x + y + z;
+}
+
+function check(f,a,b,c) {
+  assertEquals(a * 19 + b * 23 + c * 29, f(a,b,c));
+}
+
+check(f1, 50000,     5,     6);
+check(f2,     4, 50000,     6);
+check(f3,    11,    12, 50000);