[turbofan] Combine Word32And with Int32Add and negative power of two.

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 119 matching lines @@
       if (m.LeftEqualsRight()) return Replace(m.left().node());  // x & x => x
       if (m.left().IsWord32And() && m.right().HasValue()) {
         Int32BinopMatcher mleft(m.left().node());
         if (mleft.right().HasValue()) {  // (x & K) & K => x & K
           node->ReplaceInput(0, mleft.left().node());
           node->ReplaceInput(
               1, Int32Constant(m.right().Value() & mleft.right().Value()));
           return Changed(node);
         }
       }
+      if (m.left().IsInt32Add() && m.right().IsNegativePowerOf2()) {
+        Int32BinopMatcher mleft(m.left().node());
+        if (mleft.right().HasValue() &&
+            (mleft.right().Value() & m.right().Value()) ==
+                mleft.right().Value()) {
+          // (x + K) & K => (x & K) + K

[Jarin, 2014/11/24 12:28:09]

How about (x + K1) & K2 => (x & K2) + K1?

[Benedikt Meurer, 2014/11/24 12:29:33]

This was the terminology that we always used here. Don't want to change that
now.

+          return Replace(graph()->NewNode(
+              machine()->Int32Add(),
+              graph()->NewNode(machine()->Word32And(), mleft.left().node(),
+                               m.right().node()),
+              mleft.right().node()));

[Jarin, 2014/11/24 12:28:09]

Funny indentation.

[Benedikt Meurer, 2014/11/24 12:29:33]

clang-format...

+        }
+      }
       break;
     }
     case IrOpcode::kWord32Or: {
       Int32BinopMatcher m(node);
       if (m.right().Is(0)) return Replace(m.left().node());    // x | 0  => x
       if (m.right().Is(-1)) return Replace(m.right().node());  // x | -1 => -1
       if (m.IsFoldable()) {                                    // K | K  => K
         return ReplaceInt32(m.left().Value() | m.right().Value());
       }
       if (m.LeftEqualsRight()) return Replace(m.left().node());  // x | x => x
@@ skipping 686 matching lines @@
 MachineOperatorBuilder* MachineOperatorReducer::machine() const {
   return jsgraph()->machine();
 }
 
 
 Graph* MachineOperatorReducer::graph() const { return jsgraph()->graph(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8