[ARM64] [turbofan] Improve construction of doubles.

src/compiler/arm64/instruction-selector-arm64.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"
 #include "src/compiler/node-properties.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 1588 matching lines @@
 
 
 void InstructionSelector::VisitFloat64ExtractHighWord32(Node* node) {
   Arm64OperandGenerator g(this);
   Emit(kArm64Float64ExtractHighWord32, g.DefineAsRegister(node),
        g.UseRegister(node->InputAt(0)));
 }
 
 
 void InstructionSelector::VisitFloat64InsertLowWord32(Node* node) {
-  // TODO(arm64): Some AArch64 specialist should be able to improve this.
   Arm64OperandGenerator g(this);
   Node* left = node->InputAt(0);
   Node* right = node->InputAt(1);
+  if (left->opcode() == IrOpcode::kFloat64InsertHighWord32 &&
+      CanCover(node, left)) {
+    Node* right_of_left = left->InputAt(1);
+    Emit(kArm64Bfi, g.DefineSameAsFirst(right), g.UseRegister(right),
+         g.UseRegister(right_of_left), g.TempImmediate(32),
+         g.TempImmediate(32));
+    Emit(kArm64Float64MoveU64, g.DefineAsRegister(node), g.UseRegister(right));
+    return;
+  }
   Emit(kArm64Float64InsertLowWord32, g.DefineAsRegister(node),
        g.UseRegister(left), g.UseRegister(right));
 }
 
 
 void InstructionSelector::VisitFloat64InsertHighWord32(Node* node) {
-  // TODO(arm64): Some AArch64 specialist should be able to improve this.
   Arm64OperandGenerator g(this);
   Node* left = node->InputAt(0);
   Node* right = node->InputAt(1);
+  if (left->opcode() == IrOpcode::kFloat64InsertLowWord32 &&
+      CanCover(node, left)) {
+    Node* right_of_left = left->InputAt(1);
+    Emit(kArm64Bfi, g.DefineSameAsFirst(left), g.UseRegister(right_of_left),
+         g.UseRegister(right), g.TempImmediate(32), g.TempImmediate(32));
+    Emit(kArm64Float64MoveU64, g.DefineAsRegister(node), g.UseRegister(left));
+    return;
+  }
   Emit(kArm64Float64InsertHighWord32, g.DefineAsRegister(node),
        g.UseRegister(left), g.UseRegister(right));
 }
 
 
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
   return MachineOperatorBuilder::kFloat64RoundDown |
          MachineOperatorBuilder::kFloat64RoundTruncate |
          MachineOperatorBuilder::kFloat64RoundTiesAway |
          MachineOperatorBuilder::kWord32ShiftIsSafe |
          MachineOperatorBuilder::kInt32DivIsSafe |
          MachineOperatorBuilder::kUint32DivIsSafe;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8