[turbofan] Improve reduction of Word32And and Int32Add.

test/unittests/compiler/machine-operator-reducer-unittest.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/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator-reducer.h"
 #include "src/compiler/typer.h"
 #include "test/unittests/compiler/graph-unittest.h"
@@ skipping 518 matching lines @@
   }
 }
 
 
 TEST_F(MachineOperatorReducerTest, Word32AndWithInt32AddAndConstant) {
   Node* const p0 = Parameter(0);
   Node* const p1 = Parameter(1);
 
   TRACED_FORRANGE(int32_t, l, 1, 31) {
     TRACED_FOREACH(int32_t, k, kInt32Values) {
+      if ((k << l) == 0) continue;
       // (x + (K << L)) & (-1 << L) => (x & (-1 << L)) + (K << L)
       Reduction const r = Reduce(graph()->NewNode(
           machine()->Word32And(),
           graph()->NewNode(machine()->Int32Add(), p0, Int32Constant(k << l)),
           Int32Constant(-1 << l)));
       ASSERT_TRUE(r.Changed());
       EXPECT_THAT(r.replacement(),
                   IsInt32Add(IsWord32And(p0, IsInt32Constant(-1 << l)),
                              IsInt32Constant(k << l)));
     }
@@ skipping 212 matching lines @@
     EXPECT_THAT(r.replacement(), IsWord32And(p0, IsInt32Constant(m)));
   }
 }
 
 
 TEST_F(MachineOperatorReducerTest,
        Word32ShlWithWord32SarAndInt32AddAndConstant) {
   Node* const p0 = Parameter(0);
   TRACED_FOREACH(int32_t, k, kInt32Values) {
     TRACED_FORRANGE(int32_t, l, 1, 31) {
+      if ((k << l) == 0) continue;
       // (x + (K << L)) >> L << L => (x & (-1 << L)) + (K << L)
       Reduction const r = Reduce(graph()->NewNode(
           machine()->Word32Shl(),
           graph()->NewNode(machine()->Word32Sar(),
                            graph()->NewNode(machine()->Int32Add(), p0,
                                             Int32Constant(k << l)),
                            Int32Constant(l)),
           Int32Constant(l)));
       ASSERT_TRUE(r.Changed());
       EXPECT_THAT(r.replacement(),
@@ skipping 550 matching lines @@
     Reduction r = Reduce(node);
     ASSERT_TRUE(r.Changed());
     EXPECT_THAT(r.replacement(),
                 IsStore(rep, base, index, value, effect, control));
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8