Index: lib/Basic/Targets/RISCV.h
===================================================================
--- lib/Basic/Targets/RISCV.h
+++ lib/Basic/Targets/RISCV.h
@@ -77,6 +77,7 @@
     IntPtrType = SignedInt;
     PtrDiffType = SignedInt;
     SizeType = UnsignedInt;
+    MaxAtomicInlineWidth = 32;
     resetDataLayout("e-m:e-p:32:32-i64:64-n32-S128");
   }
 
@@ -95,6 +96,7 @@
       : RISCVTargetInfo(Triple, Opts) {
     LongWidth = LongAlign = PointerWidth = PointerAlign = 64;
     IntMaxType = Int64Type = SignedLong;
+    MaxAtomicInlineWidth = 64;
     resetDataLayout("e-m:e-p:64:64-i64:64-i128:128-n64-S128");
   }