diff --git a/sdk/lib/_internal/compiler/implementation/ssa/value_range_analyzer.dart b/sdk/lib/_internal/compiler/implementation/ssa/value_range_analyzer.dart
index f580029..15f460b 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/value_range_analyzer.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/value_range_analyzer.dart
@@ -774,7 +774,7 @@
       relational.block.rewrite(
           relational, graph.addConstantBool(true, compiler));
       relational.block.remove(relational);
-    } else if (reverseOperation(operation).apply(leftRange, rightRange)) {
+    } else if (negateOperation(operation).apply(leftRange, rightRange)) {
       relational.block.rewrite(
           relational, graph.addConstantBool(false, compiler));
       relational.block.remove(relational);
@@ -885,7 +885,7 @@
     return newInstruction;
   }
 
-  static BinaryOperation reverseOperation(BinaryOperation operation) {
+  static BinaryOperation negateOperation(BinaryOperation operation) {
     if (operation == const LessOperation()) {
       return const GreaterEqualOperation();
     } else if (operation == const LessEqualOperation()) {
@@ -899,6 +899,20 @@
     }
   }
 
+  static BinaryOperation flipOperation(BinaryOperation operation) {
+    if (operation == const LessOperation()) {
+      return const GreaterOperation();
+    } else if (operation == const LessEqualOperation()) {
+      return const GreaterEqualOperation();
+    } else if (operation == const GreaterOperation()) {
+      return const LessOperation();
+    } else if (operation == const GreaterEqualOperation()) {
+      return const LessEqualOperation();
+    } else {
+      return null;
+    }
+  }
+
   Range computeConstrainedRange(BinaryOperation operation,
                                 Range leftRange,
                                 Range rightRange) {
@@ -932,7 +946,7 @@
     Range rightRange = ranges[right];
     Range leftRange = ranges[left];
     Operation operation = condition.operation(constantSystem);
-    Operation reverse = reverseOperation(operation);
+    Operation mirrorOp = flipOperation(operation);
     // Only update the true branch if this block is the only
     // predecessor.
     if (branch.trueBranch.predecessors.length == 1) {
@@ -946,7 +960,7 @@
         ranges[instruction] = range;
       }
 
-      range = computeConstrainedRange(reverse, rightRange, leftRange);
+      range = computeConstrainedRange(mirrorOp, rightRange, leftRange);
       if (rightRange != range) {
         HInstruction instruction =
             createRangeConversion(branch.trueBranch.first, right);
@@ -958,6 +972,8 @@
     // predecessor.
     if (branch.falseBranch.predecessors.length == 1) {
       assert(branch.falseBranch.predecessors[0] == branch.block);
+      Operation reverse = negateOperation(operation);
+      Operation reversedMirror = flipOperation(reverse);
       // Update the false branch to use narrower ranges for [left] and
       // [right].
       Range range = computeConstrainedRange(reverse, leftRange, rightRange);
@@ -967,7 +983,7 @@
         ranges[instruction] = range;
       }
 
-      range = computeConstrainedRange(operation, rightRange, leftRange);
+      range = computeConstrainedRange(reversedMirror, rightRange, leftRange);
       if (rightRange != range) {
         HInstruction instruction =
             createRangeConversion(branch.falseBranch.first, right);
diff --git a/tests/language/range_analysis3_test.dart b/tests/language/range_analysis3_test.dart
new file mode 100644
index 0000000..5628e46
--- /dev/null
+++ b/tests/language/range_analysis3_test.dart
@@ -0,0 +1,210 @@
+// Copyright (c) 2014, 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 "package:expect/expect.dart";
+
+confuse(x) {
+  if (new DateTime.now().millisecondsSinceEpoch == 0) {
+    return confuse(x + 1);
+  } else if (new DateTime.now().millisecondsSinceEpoch == 0) {
+    return confuse(x - 1);
+  }
+  return x;
+}
+
+test1() {
+  int x = 0;
+  // Give x a range of -1 to 0.
+  if (confuse(0) == 1) x = -1;
+
+  int y = 0;
+  // Give y a range of 0 to 1.
+  if (confuse(0) == 1) y = 1;
+
+  var zero = 0;
+
+  var status = "bad";
+  if (x < zero) {
+    Expect.fail("unreachable");
+  } else {
+    // Dart2js must not conclude that zero has a range of [-1, 0].
+    if (y <= zero) {
+      status = "good";
+    }
+  }
+  Expect.equals("good", status);
+}
+
+test2() {
+  int x = 0;
+  // Give x a range of -1 to 0.
+  if (confuse(0) == 1) x = -1;
+
+  int y = 0;
+  // Give y a range of -1 to 1.
+  if (confuse(0) == 1) y = 1;
+  if (confuse(1) == 2) y = -1;
+
+  var status = "good";
+  if (x < y) {
+    Expect.fail("unreachable");
+  } else {
+    // Dart2js must not conclude that y has a range of [-1, -1].
+    if (y == -1) {
+      status = "bad";
+    }
+  }
+  Expect.equals("good", status);
+}
+
+test3a() {
+  int x = 0;
+  // Give x a range of -1 to 1.
+  if (confuse(0) == 1) x = -1;
+  if (confuse(1) == 2) x = 1;
+
+  int y = 0;
+  // Give y a range of -1 to 1.
+  if (confuse(0) == 1) y = 1;
+  if (confuse(1) == 2) y = -1;
+
+  var status = "good";
+  if (x < y) {
+    Expect.fail("unreachable");
+  } else {
+    // Test that the range-analysis does not lose a value.
+    if (x <= -1) status = "bad";
+    if (x >= 1) status = "bad";
+    if (x < 0) status = "bad";
+    if (x > 0) status = "bad";
+    if (-1 >= x) status = "bad";
+    if (1 <= x) status = "bad";
+    if (0 > x) status = "bad";
+    if (0 < x) status = "bad";
+    if (y <= -1) status = "bad";
+    if (y >= 1) status = "bad";
+    if (y < 0) status = "bad";
+    if (y > 0) status = "bad";
+    if (-1 >= y) status = "bad";
+    if (1 <= y) status = "bad";
+    if (0 > y) status = "bad";
+    if (0 < y) status = "bad";
+  }
+  Expect.equals("good", status);
+}
+
+test3b() {
+  int x = 0;
+  // Give x a range of -2 to 0.
+  if (confuse(0) == 1) x = -2;
+
+  int y = 0;
+  // Give y a range of -1 to 1.
+  if (confuse(0) == 1) y = 1;
+  if (confuse(1) == 2) y = -1;
+
+  var status = "good";
+  if (x < y) {
+    Expect.fail("unreachable");
+  } else {
+    // Test that the range-analysis does not lose a value.
+    if (x <= -1) status = "bad";
+    if (x >= 1) status = "bad";
+    if (x < 0) status = "bad";
+    if (x > 0) status = "bad";
+    if (-1 >= x) status = "bad";
+    if (1 <= x) status = "bad";
+    if (0 > x) status = "bad";
+    if (0 < x) status = "bad";
+    if (y <= -1) status = "bad";
+    if (y >= 1) status = "bad";
+    if (y < 0) status = "bad";
+    if (y > 0) status = "bad";
+    if (-1 >= y) status = "bad";
+    if (1 <= y) status = "bad";
+    if (0 > y) status = "bad";
+    if (0 < y) status = "bad";
+  }
+  Expect.equals("good", status);
+}
+
+test4a() {
+  int x = -1;
+  // Give x a range of -1 to 1.
+  if (confuse(0) == 1) x = 1;
+
+  int y = 0;
+  // Give y a range of -1 to 1.
+  if (confuse(0) == 1) y = 1;
+  if (confuse(1) == 2) y = -1;
+
+  var status = "good";
+  if (x < y) {
+    // Test that the range-analysis does not lose a value.
+    if (x <= -2) status = "bad";
+    if (x >= 0) status = "bad";
+    if (x < -1) status = "bad";
+    if (x > -1) status = "bad";
+    if (-2 >= x) status = "bad";
+    if (0 <= x) status = "bad";
+    if (-1 > x) status = "bad";
+    if (-1 < x) status = "bad";
+    if (y <= -1) status = "bad";
+    if (y >= 1) status = "bad";
+    if (y < 0) status = "bad";
+    if (y > 0) status = "bad";
+    if (-1 >= y) status = "bad";
+    if (1 <= y) status = "bad";
+    if (0 > y) status = "bad";
+    if (0 < y) status = "bad";
+  } else {
+    Expect.fail("unreachable");
+  }
+  Expect.equals("good", status);
+}
+
+test4b() {
+  int x = -1;
+  // Give x a range of -2 to 0.
+  if (confuse(0) == 1) x = -2;
+  if (confuse(1) == 2) x = 0;
+
+  int y = 0;
+  // Give y a range of -1 to 1.
+  if (confuse(0) == 1) y = 1;
+  if (confuse(1) == 2) y = -1;
+
+  var status = "good";
+  if (x < y) {
+    // Test that the range-analysis does not lose a value.
+    if (x <= -2) status = "bad";
+    if (x >= 0) status = "bad";
+    if (x < -1) status = "bad";
+    if (x > -1) status = "bad";
+    if (-2 >= x) status = "bad";
+    if (0 <= x) status = "bad";
+    if (-1 > x) status = "bad";
+    if (-1 < x) status = "bad";
+    if (y <= -1) status = "bad";
+    if (y >= 1) status = "bad";
+    if (y < 0) status = "bad";
+    if (y > 0) status = "bad";
+    if (-1 >= y) status = "bad";
+    if (1 <= y) status = "bad";
+    if (0 > y) status = "bad";
+    if (0 < y) status = "bad";
+  } else {
+    Expect.fail("unreachable");
+  }
+  Expect.equals("good", status);
+}
+
+main() {
+  test1();
+  test2();
+  test3a();
+  test3b();
+  test4a();
+  test4b();
+}
\ No newline at end of file
diff --git a/tools/VERSION b/tools/VERSION
index 7a8f7e4..52dc946 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -26,6 +26,6 @@
 CHANNEL stable
 MAJOR 1
 MINOR 5
-PATCH 6
+PATCH 7
 PRERELEASE 0
 PRERELEASE_PATCH 0