[x64] Fix optimization for certain checked load/stores.

src/compiler/x64/instruction-selector-x64.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/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 212 matching lines @@
     case kRepFloat32:
       opcode = kCheckedLoadFloat32;
       break;
     case kRepFloat64:
       opcode = kCheckedLoadFloat64;
       break;
     default:
       UNREACHABLE();
       return;
   }
-  InstructionOperand* offset_operand = g.UseRegister(offset);
+  if (offset->opcode() == IrOpcode::kInt32Add && CanCover(node, offset)) {
+    Int32Matcher mlength(length);
+    Int32BinopMatcher moffset(offset);
+    if (mlength.HasValue() && moffset.right().HasValue() &&
+        mlength.Value() >= moffset.right().Value()) {
+      Emit(opcode, g.DefineAsRegister(node), g.UseRegister(buffer),
+           g.UseRegister(moffset.left().node()),
+           g.UseImmediate(moffset.right().node()), g.UseImmediate(length));
+      return;
+    }
+  }
   InstructionOperand* length_operand =
       g.CanBeImmediate(length) ? g.UseImmediate(length) : g.UseRegister(length);
-  Emit(opcode | AddressingModeField::encode(kMode_MR1),
-       g.DefineAsRegister(node), offset_operand, length_operand,
-       g.UseRegister(buffer), offset_operand);
+  Emit(opcode, g.DefineAsRegister(node), g.UseRegister(buffer),
+       g.UseRegister(offset), g.TempImmediate(0), length_operand);
 }
 
 
 void InstructionSelector::VisitCheckedStore(Node* node) {
   MachineType rep = RepresentationOf(OpParameter<MachineType>(node));
   X64OperandGenerator g(this);
   Node* const buffer = node->InputAt(0);
   Node* const offset = node->InputAt(1);
   Node* const length = node->InputAt(2);
   Node* const value = node->InputAt(3);
@@ skipping 13 matching lines @@
       break;
     case kRepFloat64:
       opcode = kCheckedStoreFloat64;
       break;
     default:
       UNREACHABLE();
       return;
   }
   InstructionOperand* value_operand =
       g.CanBeImmediate(value) ? g.UseImmediate(value) : g.UseRegister(value);
-  InstructionOperand* offset_operand = g.UseRegister(offset);
+  if (offset->opcode() == IrOpcode::kInt32Add && CanCover(node, offset)) {
+    Int32Matcher mlength(length);
+    Int32BinopMatcher moffset(offset);
+    if (mlength.HasValue() && moffset.right().HasValue() &&
+        mlength.Value() >= moffset.right().Value()) {
+      Emit(opcode, nullptr, g.UseRegister(buffer),
+           g.UseRegister(moffset.left().node()),
+           g.UseImmediate(moffset.right().node()), g.UseImmediate(length),
+           value_operand);
+      return;
+    }
+  }
   InstructionOperand* length_operand =
       g.CanBeImmediate(length) ? g.UseImmediate(length) : g.UseRegister(length);
-  Emit(opcode | AddressingModeField::encode(kMode_MR1), nullptr, offset_operand,
-       length_operand, value_operand, g.UseRegister(buffer), offset_operand);
+  Emit(opcode, nullptr, g.UseRegister(buffer), g.UseRegister(offset),
+       g.TempImmediate(0), length_operand, value_operand);
 }
 
 
 // Shared routine for multiple binary operations.
 static void VisitBinop(InstructionSelector* selector, Node* node,
                        InstructionCode opcode, FlagsContinuation* cont) {
   X64OperandGenerator g(selector);
   Int32BinopMatcher m(node);
   Node* left = m.left().node();
   Node* right = m.right().node();
@@ skipping 998 matching lines @@
            MachineOperatorBuilder::kFloat64Ceil |
            MachineOperatorBuilder::kFloat64RoundTruncate |
            MachineOperatorBuilder::kWord32ShiftIsSafe;
   }
   return MachineOperatorBuilder::kNoFlags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8