diff -r 000000000000 -r 6474c204b198 js/src/jit/EdgeCaseAnalysis.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit/EdgeCaseAnalysis.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,44 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "jit/EdgeCaseAnalysis.h"
+
+#include "jit/MIR.h"
+#include "jit/MIRGraph.h"
+
+using namespace js;
+using namespace js::jit;
+
+EdgeCaseAnalysis::EdgeCaseAnalysis(MIRGenerator *mir, MIRGraph &graph)
+  : mir(mir), graph(graph)
+{
+}
+
+bool
+EdgeCaseAnalysis::analyzeLate()
+{
+    // Renumber definitions for NeedNegativeZeroCheck under analyzeEdgeCasesBackward.
+    uint32_t nextId = 1;
+
+    for (ReversePostorderIterator block(graph.rpoBegin()); block != graph.rpoEnd(); block++) {
+        if (mir->shouldCancel("Analyze Late (first loop)"))
+            return false;
+        for (MDefinitionIterator iter(*block); iter; iter++) {
+            iter->setId(nextId++);
+            iter->analyzeEdgeCasesForward();
+        }
+        block->lastIns()->setId(nextId++);
+    }
+
+    for (PostorderIterator block(graph.poBegin()); block != graph.poEnd(); block++) {
+        if (mir->shouldCancel("Analyze Late (second loop)"))
+            return false;
+        for (MInstructionReverseIterator riter(block->rbegin()); riter != block->rend(); riter++)
+            riter->analyzeEdgeCasesBackward();
+    }
+
+    return true;
+}