Implement optional turbofan UnalignedLoad and UnalignedStore operators

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 68e393aaddf74fbbf650fb87a9b66c2400406eac..986310f2caca700609549225d1a27c7e1c2d9527 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -90,6 +90,15 @@ std::ostream& operator<<(std::ostream&, StoreRepresentation);
 
 StoreRepresentation const& StoreRepresentationOf(Operator const*);
 
+typedef MachineType UnalignedLoadRepresentation;
+
+UnalignedLoadRepresentation UnalignedLoadRepresentationOf(Operator const*);
+
+// An UnalignedStore needs a MachineType.
+typedef MachineRepresentation UnalignedStoreRepresentation;
+
+UnalignedStoreRepresentation const& UnalignedStoreRepresentationOf(
+    Operator const*);
 
 // A CheckedLoad needs a MachineType.
 typedef MachineType CheckedLoadRepresentation;
@@ -137,13 +146,16 @@ class MachineOperatorBuilder final : public ZoneObject {
     kWord64Popcnt = 1u << 19,
     kWord32ReverseBits = 1u << 20,
     kWord64ReverseBits = 1u << 21,
+    kUnalignedLoad = 1u << 22,
+    kUnalignedStore = 1u << 23,
     kAllOptionalOps = kFloat32Max | kFloat32Min | kFloat64Max | kFloat64Min |
                       kFloat32RoundDown | kFloat64RoundDown | kFloat32RoundUp |
                       kFloat64RoundUp | kFloat32RoundTruncate |
                       kFloat64RoundTruncate | kFloat64RoundTiesAway |
                       kFloat32RoundTiesEven | kFloat64RoundTiesEven |
                       kWord32Ctz | kWord64Ctz | kWord32Popcnt | kWord64Popcnt |
-                      kWord32ReverseBits | kWord64ReverseBits
+                      kWord32ReverseBits | kWord64ReverseBits | kUnalignedLoad |
+                      kUnalignedStore
   };
   typedef base::Flags<Flag, unsigned> Flags;
 
@@ -323,6 +335,12 @@ class MachineOperatorBuilder final : public ZoneObject {
   // store [base + index], value
   const Operator* Store(StoreRepresentation rep);
 
+  // unaligned load [base + index]
+  const OptionalOperator UnalignedLoad(UnalignedLoadRepresentation rep);
+
+  // unaligned store [base + index], value
+  const OptionalOperator UnalignedStore(UnalignedStoreRepresentation rep);
+
   const Operator* StackSlot(MachineRepresentation rep);
 
   // Access to the machine stack.