[turbofan] Introduce optional Float64Min and Float64Max machine operators.

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 50fe0df1904b8cb77ae3b476d42233e12252d221..ac06da397a52751445addbca8144eeaaac2c60a7 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -900,6 +900,30 @@ void InstructionSelector::VisitFloat64Mod(Node* node) {
 }
 
 
+void InstructionSelector::VisitFloat64Max(Node* node) {
+  X64OperandGenerator g(this);
+  if (IsSupported(AVX)) {
+    Emit(kAVXFloat64Max, g.DefineAsRegister(node),
+         g.UseRegister(node->InputAt(0)), g.Use(node->InputAt(1)));
+  } else {
+    Emit(kSSEFloat64Max, g.DefineSameAsFirst(node),
+         g.UseRegister(node->InputAt(0)), g.Use(node->InputAt(1)));
+  }
+}
+
+
+void InstructionSelector::VisitFloat64Min(Node* node) {
+  X64OperandGenerator g(this);
+  if (IsSupported(AVX)) {
+    Emit(kAVXFloat64Min, g.DefineAsRegister(node),
+         g.UseRegister(node->InputAt(0)), g.Use(node->InputAt(1)));
+  } else {
+    Emit(kSSEFloat64Min, g.DefineSameAsFirst(node),
+         g.UseRegister(node->InputAt(0)), g.Use(node->InputAt(1)));
+  }
+}
+
+
 void InstructionSelector::VisitFloat64Sqrt(Node* node) {
   X64OperandGenerator g(this);
   Emit(kSSEFloat64Sqrt, g.DefineAsRegister(node), g.Use(node->InputAt(0)));
@@ -1449,6 +1473,8 @@ void InstructionSelector::VisitFloat64InsertHighWord32(Node* node) {
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
   MachineOperatorBuilder::Flags flags =
+      MachineOperatorBuilder::kFloat64Max |
+      MachineOperatorBuilder::kFloat64Min |
       MachineOperatorBuilder::kWord32ShiftIsSafe;
   if (CpuFeatures::IsSupported(SSE4_1)) {
     flags |= MachineOperatorBuilder::kFloat64RoundDown |