Index: lib/Target/AArch64/AArch64SchedThunderX2T99.td
===================================================================
--- lib/Target/AArch64/AArch64SchedThunderX2T99.td
+++ lib/Target/AArch64/AArch64SchedThunderX2T99.td
@@ -391,7 +391,7 @@
 def : WriteRes<WriteHint,    []> { let Latency = 1; }
 
 def : WriteRes<WriteAtomic,  []> {
-  let Unsupported = 1;
+  let Latency = 4;
   let NumMicroOps = 2;
 }