Change the Hydrogen representation of uses.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 620bbc94e521df8d43e3429196821ac2cfc055c6..931424ee055c4997c934c2d4c054fca49cc172c9 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -851,24 +851,22 @@ LInstruction* LChunkBuilder::DoShift(Token::Value op,
     right = UseFixed(right_value, rcx);
   }
 
-  // Shift operations can only deoptimize if we do a logical shift
-  // by 0 and the result cannot be truncated to int32.
-  bool can_deopt = (op == Token::SHR && constant_value == 0);
-  if (can_deopt) {
-    bool can_truncate = true;
-    for (int i = 0; i < instr->uses()->length(); i++) {
-      if (!instr->uses()->at(i)->CheckFlag(HValue::kTruncatingToInt32)) {
-        can_truncate = false;
+  // Shift operations can only deoptimize if we do a logical shift by 0 and
+  // the result cannot be truncated to int32.
+  bool may_deopt = (op == Token::SHR && constant_value == 0);
+  bool does_deopt = false;
+  if (may_deopt) {
+    for (HUseIterator it(instr->uses()); !it.Done(); it.Advance()) {
+      if (!it.value()->CheckFlag(HValue::kTruncatingToInt32)) {
+        does_deopt = true;
         break;
       }
     }
-    can_deopt = !can_truncate;
   }
 
-  LShiftI* result = new LShiftI(op, left, right, can_deopt);
-  return can_deopt
-      ? AssignEnvironment(DefineSameAsFirst(result))
-      : DefineSameAsFirst(result);
+  LInstruction* result =
+      DefineSameAsFirst(new LShiftI(op, left, right, does_deopt));
+  return does_deopt ? AssignEnvironment(result) : result;
 }