Fix error in postfix ++ in Crankshaft.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 1880111a5eef927880749071ad03e40e89865517..dc15532fa35f51f1e2ad4032786c86e4fb6ce035 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -1638,6 +1638,13 @@ HValue* HChange::EnsureAndPropagateNotMinusZero(BitVector* visited) {
 }
 
 
+HValue* HForceRepresentation::EnsureAndPropagateNotMinusZero(
+    BitVector* visited) {
+  visited->Add(id());
+  return value();
+}
+
+
 HValue* HMod::EnsureAndPropagateNotMinusZero(BitVector* visited) {
   visited->Add(id());
   if (range() == NULL || range()->CanBeMinusZero()) {