diff --git a/state/execution.go b/state/execution.go
index 810d24b01..a94bbdbf7 100644
--- a/state/execution.go
+++ b/state/execution.go
@@ -158,6 +158,18 @@ func updateValidators(validators *types.ValidatorSet, changedValidators []*abci.
 	return nil
 }
 
+// return a bit array of validators that signed the last commit
+// NOTE: assumes commits have already been authenticated
+func commitBitArrayFromBlock(block *types.Block) *cmn.BitArray {
+	signed := cmn.NewBitArray(len(block.LastCommit.Precommits))
+	for i, precommit := range block.LastCommit.Precommits {
+		if precommit != nil {
+			signed.SetIndex(i, true) // val_.LastCommitHeight = block.Height - 1
+		}
+	}
+	return signed
+}
+
 //-----------------------------------------------------
 // Validate block