Deal with more conditional expressions in the value range analyzer.

tests/compiler/dart2js/value_range_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #import("compiler_helper.dart");
 
 const int REMOVED = 0;
 const int ABOVE_ZERO = 1;
 const int BELOW_LENGTH = 2;
 const int KEPT = 3;
@@ skipping 110 matching lines @@
 }
 """,
 ONE_ZERO_CHECK,
 
 """
 main(value) {
   var a = new List();
   return a[1] + a[0];
 }
 """,
-ONE_CHECK
+ONE_CHECK,
+
+"""
+main() {
+  var a = new List();
+  var sum = 0;
+  for (int i = 0; i <= a.length - 1; i++) {
+    sum += a[i];
+  }
+  return sum;
+}
+""",
+REMOVED,
+
+"""
+main() {
+  var a = new List();
+  var sum = 0;
+  for (int i = a.length - 1; i >=0; i--) {
+    sum += a[i];
+  }
+  return sum;
+}
+""",
+REMOVED,
+
+"""
+main(value) {
+  // Force [value] to be an int by having the speculative optimizer
+  // want an int.
+  int sum = 0;
+  for (int i = 0; i < 42; i++) sum += (value & 4);
+  var a = new List();
+  if (value > a.length - 1) return;
+  if (value < 0) return;
+  return a[value];
+}
+""",
+REMOVED,
+
+"""
+main(value) {
+  // Force [value] to be an int by having the speculative optimizer
+  // want an int.
+  int sum = 0;
+  for (int i = 0; i < 42; i++) sum += (value & 4);
+  var a = new List();
+  if (value <= a.length - 1) {
+    if (value >= 0) {
+      return a[value];
+    }
+  }
+}
+""",
+REMOVED,
+"""
+main(value) {
+  // Force [value] to be an int by having the speculative optimizer
+  // want an int.
+  int sum = 0;
+  for (int i = 0; i < 42; i++) sum += (value & 4);
+  var a = new List();
+  if (value >= a.length) return;
+  if (value <= -1) return;
+  return a[value];
+}
+""",
+REMOVED,
 ];
 
 expect(String code, int kind) {
   String generated = compile(code);
   switch (kind) {
     case REMOVED:
       Expect.isTrue(!generated.contains('ioore'));
       break;
 
     case ABOVE_ZERO:
@@ skipping 24 matching lines @@
       break;
   }
 }
 
 
 main() {
   for (int i = 0; i < TESTS.length;  i += 2) {
     expect(TESTS[i], TESTS[i + 1]);
   }
 }