Implement UnaligedLoad and UnaligedStore turbofan 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 5886bd445e8b1f6c4b7d1a0e67bf88ae6e2ba517..4f8612a7acd9be07a6a54f64985bcbe3b10ac4fe 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -70,6 +70,15 @@ 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;
@@ -95,27 +104,34 @@ class MachineOperatorBuilder final : public ZoneObject {
   // for operations that are unsupported by some back-ends.
   enum Flag : unsigned {
     kNoFlags = 0u,
-    kFloat32RoundDown = 1u << 0,
-    kFloat64RoundDown = 1u << 1,
-    kFloat32RoundUp = 1u << 2,
-    kFloat64RoundUp = 1u << 3,
-    kFloat32RoundTruncate = 1u << 4,
-    kFloat64RoundTruncate = 1u << 5,
-    kFloat32RoundTiesEven = 1u << 6,
-    kFloat64RoundTiesEven = 1u << 7,
-    kFloat64RoundTiesAway = 1u << 8,
-    kInt32DivIsSafe = 1u << 9,
-    kUint32DivIsSafe = 1u << 10,
-    kWord32ShiftIsSafe = 1u << 11,
-    kWord32Ctz = 1u << 12,
-    kWord64Ctz = 1u << 13,
-    kWord32Popcnt = 1u << 14,
-    kWord64Popcnt = 1u << 15,
-    kWord32ReverseBits = 1u << 16,
-    kWord64ReverseBits = 1u << 17,
-    kFloat32Neg = 1u << 18,
-    kFloat64Neg = 1u << 19,
+    // Note that Float*Max behaves like `(b < a) ? a : b`, not like Math.max().
+    // Note that Float*Min behaves like `(a < b) ? a : b`, not like Math.min().
+    kFloat32Max = 1u << 0,
+    kFloat32Min = 1u << 1,
+    kFloat64Max = 1u << 2,
+    kFloat64Min = 1u << 3,
+    kFloat32RoundDown = 1u << 4,
+    kFloat64RoundDown = 1u << 5,
+    kFloat32RoundUp = 1u << 6,
+    kFloat64RoundUp = 1u << 7,
+    kFloat32RoundTruncate = 1u << 8,
+    kFloat64RoundTruncate = 1u << 9,
+    kFloat32RoundTiesEven = 1u << 10,
+    kFloat64RoundTiesEven = 1u << 11,
+    kFloat64RoundTiesAway = 1u << 12,
+    kInt32DivIsSafe = 1u << 13,
+    kUint32DivIsSafe = 1u << 14,
+    kWord32ShiftIsSafe = 1u << 15,
+    kWord32Ctz = 1u << 16,
+    kWord64Ctz = 1u << 17,
+    kWord32Popcnt = 1u << 18,
+    kWord64Popcnt = 1u << 19,
+    kWord32ReverseBits = 1u << 20,
+    kWord64ReverseBits = 1u << 21,
+    kFloat32Neg = 1u << 22,
+    kFloat64Neg = 1u << 23,
     kAllOptionalOps =
+        kFloat32Max | kFloat32Min | kFloat64Max | kFloat64Min |
         kFloat32RoundDown | kFloat64RoundDown | kFloat32RoundUp |
         kFloat64RoundUp | kFloat32RoundTruncate | kFloat64RoundTruncate |
         kFloat64RoundTiesAway | kFloat32RoundTiesEven | kFloat64RoundTiesEven |
@@ -191,7 +207,7 @@ class MachineOperatorBuilder final : public ZoneObject {
       MachineRepresentation word = MachineType::PointerRepresentation(),
       Flags supportedOperators = kNoFlags,
       AlignmentRequirements alignmentRequirements =
-          AlignmentRequirements::NoUnalignedAccessSupport());
+          AlignmentRequirements::FullUnalignedAccessSupport());
 
   const Operator* Comment(const char* msg);
   const Operator* DebugBreak();
@@ -591,6 +607,12 @@ class MachineOperatorBuilder final : public ZoneObject {
   // store [base + index], value
   const Operator* Store(StoreRepresentation rep);
 
+  // unaligned load [base + index]
+  const Operator* UnalignedLoad(UnalignedLoadRepresentation rep);
+
+  // unaligned store [base + index], value
+  const Operator* UnalignedStore(UnalignedStoreRepresentation rep);
+
   const Operator* StackSlot(MachineRepresentation rep);
 
   // Access to the machine stack.