[turbofan] Introduce ToBooleanHints on ToBoolean operators.

src/compiler/type-hints.cc

Index: src/compiler/type-hints.cc
diff --git a/src/compiler/type-hints.cc b/src/compiler/type-hints.cc
index 2cf8f4d6c0ac2174c2aa872bbb6cc325306dd20e..06abad6380ef77f15981b41454c716311d89ce59 100644
--- a/src/compiler/type-hints.cc
+++ b/src/compiler/type-hints.cc
@@ -32,6 +32,52 @@ std::ostream& operator<<(std::ostream& os, BinaryOperationHints hints) {
   return os << hints.left() << "*" << hints.right() << "->" << hints.result();
 }
 
+
+std::ostream& operator<<(std::ostream& os, ToBooleanHint hint) {
+  switch (hint) {
+    case ToBooleanHint::kNone:
+      return os << "None";
+    case ToBooleanHint::kUndefined:
+      return os << "Undefined";
+    case ToBooleanHint::kBoolean:
+      return os << "Boolean";
+    case ToBooleanHint::kNull:
+      return os << "Null";
+    case ToBooleanHint::kSmallInteger:
+      return os << "SmallInteger";
+    case ToBooleanHint::kReceiver:
+      return os << "Receiver";
+    case ToBooleanHint::kString:
+      return os << "String";
+    case ToBooleanHint::kSymbol:
+      return os << "Symbol";
+    case ToBooleanHint::kHeapNumber:
+      return os << "HeapNumber";
+    case ToBooleanHint::kSimdValue:
+      return os << "SimdValue";
+    case ToBooleanHint::kAny:
+      return os << "Any";
+  }
+  UNREACHABLE();
+  return os;
+}
+
+
+std::ostream& operator<<(std::ostream& os, ToBooleanHints hints) {
+  if (hints == ToBooleanHint::kAny) return os << "Any";
+  if (hints == ToBooleanHint::kNone) return os << "None";
+  bool first = true;
+  for (ToBooleanHints::mask_type i = 0; i < sizeof(i) * CHAR_BIT; ++i) {
+    ToBooleanHint const hint = static_cast<ToBooleanHint>(1u << i);
+    if (hints & hint) {
+      if (!first) os << "|";
+      first = false;
+      os << hint;
+    }
+  }
+  return os;
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8