[turbofan] Avoid useless bit masking in typed lowering.

test/cctest/compiler/test-js-typed-lowering.cc

 // Copyright 2014 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.
 
 #include "src/v8.h"
 #include "test/cctest/cctest.h"
 
 #include "src/compiler/graph-inl.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/node-properties-inl.h"
@@ skipping 309 matching lines @@
       for (int k = 0; k < R.kNumberOps; k += 2) {
         Node* add = R.Binop(R.ops[k], p0, p1);
         Node* r = R.reduce(add);
 
         R.CheckPureBinop(R.ops[k + 1], r);
         Node* r0 = r->InputAt(0);
         Node* r1 = r->InputAt(1);
 
         CheckToI32(p0, r0, R.signedness[k]);
 
-        R.CheckPureBinop(IrOpcode::kWord32And, r1);
-        CheckToI32(p1, r1->InputAt(0), R.signedness[k + 1]);
-        R.CheckInt32Constant(0x1F, r1->InputAt(1));
+        if (r1->opcode() == IrOpcode::kWord32And) {
+          R.CheckPureBinop(IrOpcode::kWord32And, r1);
+          CheckToI32(p1, r1->InputAt(0), R.signedness[k + 1]);
+          R.CheckInt32Constant(0x1F, r1->InputAt(1));
+        } else {
+          CheckToI32(p1, r1, R.signedness[k]);
+        }
       }
     }
   }
 }
 
 
 // A helper class for testing lowering of bitwise operators.
 class JSBitwiseTypedLoweringTester : public JSTypedLoweringTester {
  public:
   static const int kNumberOps = 6;
@@ skipping 997 matching lines @@
           CHECK_EQ(p1, r->InputAt(0));
           CHECK_EQ(p0, r->InputAt(1));
         } else {
           CHECK_EQ(p0, r->InputAt(0));
           CHECK_EQ(p1, r->InputAt(1));
         }
       }
     }
   }
 }