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

src/compiler/x64/instruction-selector-x64.cc

Index: src/compiler/x64/instruction-selector-x64.cc
diff --git a/src/compiler/x64/instruction-selector-x64.cc b/src/compiler/x64/instruction-selector-x64.cc
index c1328b3ee30683f9c1324e5eec8abe3d59c3d646..f10ad06cb07708dfdb2f33b672e340fff80c569b 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -832,12 +832,15 @@ void InstructionSelector::VisitTruncateInt64ToInt32(Node* node) {
 
 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));
   }
 }
 
@@ -856,12 +859,15 @@ void InstructionSelector::VisitFloat64Sub(Node* node) {
 
 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));
   }
 }