[turbofan] Strength reduction of Word32And with Int32Mul.

src/compiler/machine-operator-reducer.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/compiler/machine-operator-reducer.h"
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/codegen.h"
 #include "src/compiler/diamond.h"
@@ skipping 888 matching lines @@
         if (mleftright.right().Is(base::bits::CountTrailingZeros32(mask))) {
           // (x + y << L) & (-1 << L) => (x & (-1 << L)) + y << L
           node->set_op(machine()->Int32Add());
           node->ReplaceInput(0,
                              Word32And(mleft.left().node(), m.right().node()));
           node->ReplaceInput(1, mleftright.node());
           Reduction const reduction = ReduceInt32Add(node);
           return reduction.Changed() ? reduction : Changed(node);
         }
       }
+    } else if (m.left().IsInt32Mul()) {
+      Int32BinopMatcher mleft(m.left().node());
+      if (mleft.right().IsMultipleOf(-mask)) {
+        // (x * (K << L)) & (-1 << L) => x * (K << L)
+        return Replace(mleft.node());
+      }
     }
   }
   return NoChange();
 }
 
 
 Reduction MachineOperatorReducer::ReduceWord32Or(Node* node) {
   DCHECK_EQ(IrOpcode::kWord32Or, node->opcode());
   Int32BinopMatcher m(node);
   if (m.right().Is(0)) return Replace(m.left().node());    // x | 0  => x
@@ skipping 58 matching lines @@
 MachineOperatorBuilder* MachineOperatorReducer::machine() const {
   return jsgraph()->machine();
 }
 
 
 Graph* MachineOperatorReducer::graph() const { return jsgraph()->graph(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8