[x86] Use better left operand heuristic for Float64Add and Float64Mul.

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 <algorithm>
 
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
@@ skipping 814 matching lines @@
       default:
         break;
     }
   }
   Emit(kX64Movl, g.DefineAsRegister(node), g.Use(value));
 }
 
 
 void InstructionSelector::VisitFloat64Add(Node* node) {
   X64OperandGenerator g(this);
+  Node* left = node->InputAt(0);
+  Node* right = node->InputAt(1);
+  if (g.CanBeBetterLeftOperand(right)) std::swap(left, right);
   if (IsSupported(AVX)) {
-    Emit(kAVXFloat64Add, g.DefineAsRegister(node),
-         g.UseRegister(node->InputAt(0)), g.Use(node->InputAt(1)));
+    Emit(kAVXFloat64Add, g.DefineAsRegister(node), g.UseRegister(left),
+         g.Use(right));
   } else {
-    Emit(kSSEFloat64Add, g.DefineSameAsFirst(node),
-         g.UseRegister(node->InputAt(0)), g.Use(node->InputAt(1)));
+    Emit(kSSEFloat64Add, g.DefineSameAsFirst(node), g.UseRegister(left),
+         g.Use(right));
   }
 }
 
 
 void InstructionSelector::VisitFloat64Sub(Node* node) {
   X64OperandGenerator g(this);
   if (IsSupported(AVX)) {
     Emit(kAVXFloat64Sub, g.DefineAsRegister(node),
          g.UseRegister(node->InputAt(0)), g.Use(node->InputAt(1)));
   } else {
     Emit(kSSEFloat64Sub, g.DefineSameAsFirst(node),
          g.UseRegister(node->InputAt(0)), g.Use(node->InputAt(1)));
   }
 }
 
 
 void InstructionSelector::VisitFloat64Mul(Node* node) {
   X64OperandGenerator g(this);
+  Node* left = node->InputAt(0);
+  Node* right = node->InputAt(1);
+  if (g.CanBeBetterLeftOperand(right)) std::swap(left, right);
   if (IsSupported(AVX)) {
-    Emit(kAVXFloat64Mul, g.DefineAsRegister(node),
-         g.UseRegister(node->InputAt(0)), g.Use(node->InputAt(1)));
+    Emit(kAVXFloat64Mul, g.DefineAsRegister(node), g.UseRegister(left),
+         g.Use(right));
   } else {
-    Emit(kSSEFloat64Mul, g.DefineSameAsFirst(node),
-         g.UseRegister(node->InputAt(0)), g.Use(node->InputAt(1)));
+    Emit(kSSEFloat64Mul, g.DefineSameAsFirst(node), g.UseRegister(left),
+         g.Use(right));
   }
 }
 
 
 void InstructionSelector::VisitFloat64Div(Node* node) {
   X64OperandGenerator g(this);
   if (IsSupported(AVX)) {
     Emit(kAVXFloat64Div, g.DefineAsRegister(node),
          g.UseRegister(node->InputAt(0)), g.Use(node->InputAt(1)));
   } else {
@@ skipping 517 matching lines @@
            MachineOperatorBuilder::kFloat64Ceil |
            MachineOperatorBuilder::kFloat64RoundTruncate |
            MachineOperatorBuilder::kWord32ShiftIsSafe;
   }
   return MachineOperatorBuilder::kNoFlags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8