Adding IREE_STATUS_DEFERRED. This will be used to indicate to callers that the execution of a coroutine has suspended and that a resume is required to complete it.

diff --git a/iree/base/status.c b/iree/base/status.c
index 8fe228e..ceebea4 100644
--- a/iree/base/status.c
+++ b/iree/base/status.c

@@ -220,8 +220,6 @@
       return "ALREADY_EXISTS";
     case IREE_STATUS_PERMISSION_DENIED:
       return "PERMISSION_DENIED";
-    case IREE_STATUS_UNAUTHENTICATED:
-      return "UNAUTHENTICATED";
     case IREE_STATUS_RESOURCE_EXHAUSTED:
       return "RESOURCE_EXHAUSTED";
     case IREE_STATUS_FAILED_PRECONDITION:
@@ -238,6 +236,10 @@
       return "UNAVAILABLE";
     case IREE_STATUS_DATA_LOSS:
       return "DATA_LOSS";
+    case IREE_STATUS_UNAUTHENTICATED:
+      return "UNAUTHENTICATED";
+    case IREE_STATUS_DEFERRED:
+      return "DEFERRED";
     default:
       return "";
   }

diff --git a/iree/base/status.h b/iree/base/status.h
index a26352c..7192069 100644
--- a/iree/base/status.h
+++ b/iree/base/status.h

@@ -73,24 +73,85 @@
 // Note that any code within IREE_STATUS_CODE_MASK is valid even if not
 // enumerated here. Always check for unhandled errors/have default conditions.
 typedef enum iree_status_code_e {
+  // Successful operation.
   IREE_STATUS_OK = 0,
+
+  // Operation was cancelled by the caller.
   IREE_STATUS_CANCELLED = 1,
+
+  // Unknown error, or error that could not be mapped to this enum.
   IREE_STATUS_UNKNOWN = 2,
+
+  // The caller provided an invalid argument and that future calls with the same
+  // arguments will fail. If the failure is predicated on system state that may
+  // change prefer IREE_STATUS_OUT_OF_RANGE.
   IREE_STATUS_INVALID_ARGUMENT = 3,
+
+  // A deadline was exceeded before the call could complete.
+  // This can be returned even if the operation would have completed
+  // successfully had the deadline not been met.
   IREE_STATUS_DEADLINE_EXCEEDED = 4,
+
+  // A referenced resource could not be found or was unavailable to all
+  // requesters. IREE_STATUS_PERMISSION_DENIED should be used if only an
+  // individual requester is denied access.
   IREE_STATUS_NOT_FOUND = 5,
+
+  // The resource the caller attempted to create already exists.
   IREE_STATUS_ALREADY_EXISTS = 6,
+
+  // The caller does not have permission to execute the operation or have access
+  // to the requested resources.
   IREE_STATUS_PERMISSION_DENIED = 7,
+
+  // Some resource type has been exhausted and the operation is unable to
+  // reserve what it requires, either by quota or underlying system exhaustion.
   IREE_STATUS_RESOURCE_EXHAUSTED = 8,
+
+  // The operation was rejected because the system is not in a state required
+  // for the operation's execution.
+  //
+  // Use IREE_STATUS_UNAVAILABLE if the caller can retry the operation.
+  // Use IREE_STATUS_ABORTED if the caller should restart their transaction
+  // (the entire sequence of operations is invalid).
+  // Use IREE_STATUS_FAILED_PRECONDITION if the caller should not retry until
+  // the system state has been explicitly fixed.
   IREE_STATUS_FAILED_PRECONDITION = 9,
+
+  // The operation was aborted by the system.
+  // If responding to a caller-requested cancellation use IREE_STATUS_CANCELLED.
   IREE_STATUS_ABORTED = 10,
+
+  // The operation was attempted past the valid range (of a resource, etc).
+  // Indicates the operation can be retried if the system state is fixed.
   IREE_STATUS_OUT_OF_RANGE = 11,
+
+  // Operation has not been implemented or is not supported.
   IREE_STATUS_UNIMPLEMENTED = 12,
+
+  // An internal error has occurred and some invariants expected by an
+  // underlying system have been violated. This error code is reserved for
+  // serious errors.
   IREE_STATUS_INTERNAL = 13,
+
+  // The system used to perform the operation is currently (and transiently)
+  // unavailable. Callers can retry with backoff.
   IREE_STATUS_UNAVAILABLE = 14,
+
+  // An serious unrecoverable data loss or corruption has occurred.
+  // Indicates that an underlying system or resource has failed in such a way
+  // that all related operations may produce incorrect results.
   IREE_STATUS_DATA_LOSS = 15,
+
+  // The requested operation does not have proper authentication.
+  // Callers can correct this and retry.
   IREE_STATUS_UNAUTHENTICATED = 16,
 
+  // The operation has been deferred and must be resumed at a future point.
+  // Used by resumable operations as part of scheduling and execution systems.
+  // Callers that do not handle deferred execution can treat this as a failure.
+  IREE_STATUS_DEFERRED = 17,
+
   IREE_STATUS_CODE_MASK = 0x1Fu,
 } iree_status_code_t;
 
@@ -151,6 +212,8 @@
   (iree_status_code(value) == IREE_STATUS_DATA_LOSS)
 #define iree_status_is_unauthenticated(value) \
   (iree_status_code(value) == IREE_STATUS_UNAUTHENTICATED)
+#define iree_status_is_deferred(value) \
+  (iree_status_code(value) == IREE_STATUS_DEFERRED)
 
 #define IREE_STATUS_IMPL_CONCAT_INNER_(x, y) x##y
 #define IREE_STATUS_IMPL_CONCAT_(x, y) IREE_STATUS_IMPL_CONCAT_INNER_(x, y)

diff --git a/iree/base/status_cc.h b/iree/base/status_cc.h
index 21fad56..4795dda 100644
--- a/iree/base/status_cc.h
+++ b/iree/base/status_cc.h

@@ -88,6 +88,7 @@
   kUnavailable = IREE_STATUS_UNAVAILABLE,
   kDataLoss = IREE_STATUS_DATA_LOSS,
   kUnauthenticated = IREE_STATUS_UNAUTHENTICATED,
+  kDeferred = IREE_STATUS_DEFERRED,
 };
 
 static inline const char* StatusCodeToString(StatusCode code) {

diff --git a/iree/compiler/Dialect/Util/IR/UtilTypes.h b/iree/compiler/Dialect/Util/IR/UtilTypes.h
index 2d47d4f..6527a37 100644
--- a/iree/compiler/Dialect/Util/IR/UtilTypes.h
+++ b/iree/compiler/Dialect/Util/IR/UtilTypes.h

@@ -59,6 +59,7 @@
   Unavailable = 14,
   DataLoss = 15,
   Unauthenticated = 16,
+  Deferred = 17,
   DoNotUseReservedForFutureExpansionUseDefaultInSwitchInstead_ = 20
 };