[turbofan] Introduces the BitcastWordToTaggedSigned and BitcastTaggedToWord opcodes.

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 b7748bfffb892311212cc96c6489a4181c8c662a..56cefc59239828419cfb331e7b09f54b37a41e7f 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -277,9 +277,15 @@ class MachineOperatorBuilder final : public ZoneObject {
   const Operator* Uint64LessThanOrEqual();
   const Operator* Uint64Mod();
 
+  // This operator reinterprets the bits of a tagged pointer as word.
+  const Operator* BitcastTaggedToWord();
+
   // This operator reinterprets the bits of a word as tagged pointer.
   const Operator* BitcastWordToTagged();
 
+  // This operator reinterprets the bits of a word as a Smi.
+  const Operator* BitcastWordToTaggedSigned();
+
   // JavaScript float64 to int32/uint32 truncation.
   const Operator* TruncateFloat64ToWord32();