[arm64] Don't try convert binary operation to shifted form when both operands are the same.

BUG=chromium:523307
LOG=N

Review URL: https://codereview.chromium.org/1304923003

Cr-Commit-Position: refs/heads/master@{#30538}

src/arm64/lithium-arm64.cc

@@ -2132,6 +2132,8 @@ HBitwiseBinaryOperation* LChunkBuilder::CanTransformToShiftedOp(HValue* val,
   DCHECK(hleft->representation().Equals(hinstr->representation()));
   DCHECK(hright->representation().Equals(hinstr->representation()));
 
+  if (hleft == hright) return NULL;
+
   if ((hright->IsConstant() &&
        LikelyFitsImmField(hinstr, HConstant::cast(hright)->Integer32Value())) ||
       (hinstr->IsCommutative() && hleft->IsConstant() &&

test/mjsunit/regress/regress-crbug-523307.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax
+
+function f(x) {
+  var c = x * x << 366;
+  var a = c + c;
+  return a;
+}
+
+f(1);
+f(1);
+%OptimizeFunctionOnNextCall(f);
+f(1);