[turbofan] Support for %_DoubleHi, %_DoubleLo and %_ConstructDouble.

src/compiler/machine-operator.h

Index: src/compiler/machine-operator.h
diff --git a/src/compiler/machine-operator.h b/src/compiler/machine-operator.h
index 42f313019f41152e8a88b57f6dbbeeb0ed6ba970..705183a88d3f9679b4a629f449fdb6dbd88649a7 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -177,6 +177,10 @@ class MachineOperatorBuilder FINAL : public ZoneObject {
   bool HasFloat64RoundTruncate() { return flags_ & kFloat64RoundTruncate; }
   bool HasFloat64RoundTiesAway() { return flags_ & kFloat64RoundTiesAway; }
 
+  // Floating point bit representation.
+  const Operator* Float64ExtractWord32(int location);

[Sven Panne, 2015/03/05 07:40:12]

If I see this correctly, location == 0 means "Low" and location == 1 means
"High", and there are no other allowed values. Using int and the name "location"
is a bit confusing here, it is *not* really an offset. A separate enum class
might be more appropriate IMHO.

[Benedikt Meurer, 2015/03/05 08:51:46]

Turned into dedicated opcodes instead, as per offline dicussion.

+  const Operator* Float64InsertWord32(int location);
+
   // load [base + index]
   const Operator* Load(LoadRepresentation rep);
 
@@ -226,10 +230,10 @@ class MachineOperatorBuilder FINAL : public ZoneObject {
 #undef PSEUDO_OP_LIST
 
  private:
-  Zone* zone_;
-  const MachineOperatorGlobalCache& cache_;
-  const MachineType word_;
-  const Flags flags_;
+  Zone* const zone_;
+  MachineOperatorGlobalCache const& cache_;
+  MachineType const word_;
+  Flags const flags_;
 
   DISALLOW_COPY_AND_ASSIGN(MachineOperatorBuilder);
 };