[turbofan] Further reduction of Word32And with Int32Add.

- (y * (K << L) + x) & (-1 << L) => (x & (-1 << L)) + y * (K << L)
- (x + y * (K << L)) & (-1 << L) => (x & (-1 << L)) + y * (K << L)

TEST=unittests
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/811293002

Cr-Commit-Position: refs/heads/master@{#25875}

src/compiler/machine-operator-reducer.cc

@@ -795,6 +795,29 @@ Reduction MachineOperatorReducer::ReduceWord32And(Node* node) {
       Reduction const reduction = ReduceInt32Add(node);
       return reduction.Changed() ? reduction : Changed(node);
     }
+    if (mleft.left().IsInt32Mul()) {
+      Int32BinopMatcher mleftleft(mleft.left().node());
+      if (mleftleft.right().IsMultipleOf(-m.right().Value())) {
+        // (y * (K << L) + x) & (-1 << L) => (x & (-1 << L)) + y * (K << L)
+        node->set_op(machine()->Int32Add());
+        node->ReplaceInput(0,
+                           Word32And(mleft.right().node(), m.right().node()));
+        node->ReplaceInput(1, mleftleft.node());
+        Reduction const reduction = ReduceInt32Add(node);
+        return reduction.Changed() ? reduction : Changed(node);
+      }
+    }
+    if (mleft.right().IsInt32Mul()) {
+      Int32BinopMatcher mleftright(mleft.right().node());
+      if (mleftright.right().IsMultipleOf(-m.right().Value())) {
+        // (x + y * (K << L)) & (-1 << L) => (x & (-1 << L)) + y * (K << 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);
+      }
+    }
     if (mleft.left().IsWord32Shl()) {
       Int32BinopMatcher mleftleft(mleft.left().node());
       if (mleftleft.right().Is(

src/compiler/node-matchers.h

@@ -102,6 +102,9 @@ template <typename T, IrOpcode::Value kOpcode>
 struct IntMatcher FINAL : public ValueMatcher<T, kOpcode> {
   explicit IntMatcher(Node* node) : ValueMatcher<T, kOpcode>(node) {}
 
+  bool IsMultipleOf(T n) const {
+    return this->HasValue() && (this->Value() % n) == 0;
+  }
   bool IsPowerOf2() const {
     return this->HasValue() && this->Value() > 0 &&
            (this->Value() & (this->Value() - 1)) == 0;

test/unittests/compiler/machine-operator-reducer-unittest.cc

@@ -569,6 +569,43 @@ TEST_F(MachineOperatorReducerTest, Word32AndWithInt32AddAndConstant) {
 }
 
 
+TEST_F(MachineOperatorReducerTest,
+       Word32AndWithInt32AddAndInt32MulAndConstant) {
+  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;
+      // (y * (K << L) + x) & (-1 << L) => (x & (-1 << L)) + y * (K << L)
+      Reduction const r1 = Reduce(graph()->NewNode(
+          machine()->Word32And(),
+          graph()->NewNode(machine()->Int32Add(),
+                           graph()->NewNode(machine()->Int32Mul(), p1,
+                                            Int32Constant(k << l)),
+                           p0),
+          Int32Constant(-1 << l)));
+      ASSERT_TRUE(r1.Changed());
+      EXPECT_THAT(r1.replacement(),
+                  IsInt32Add(IsWord32And(p0, IsInt32Constant(-1 << l)),
+                             IsInt32Mul(p1, IsInt32Constant(k << l))));
+
+      // (x + y * (K << L)) & (-1 << L) => (x & (-1 << L)) + y * (K << L)
+      Reduction const r2 = Reduce(graph()->NewNode(
+          machine()->Word32And(),
+          graph()->NewNode(machine()->Int32Add(), p0,
+                           graph()->NewNode(machine()->Int32Mul(), p1,
+                                            Int32Constant(k << l))),
+          Int32Constant(-1 << l)));
+      ASSERT_TRUE(r2.Changed());
+      EXPECT_THAT(r2.replacement(),
+                  IsInt32Add(IsWord32And(p0, IsInt32Constant(-1 << l)),
+                             IsInt32Mul(p1, IsInt32Constant(k << l))));
+    }
+  }
+}
+
+
 // -----------------------------------------------------------------------------
 // Word32Xor