Fix an obvious typo which caused an isel assertion. rdar://8964854.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125023 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 59a7155..4afc8c7 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -4344,7 +4344,7 @@
   default: llvm_unreachable("unsupported size for AtomicCmpSwap!");
   case 1:
     ldrOpc = isThumb2 ? ARM::t2LDREXB : ARM::LDREXB;
-    strOpc = isThumb2 ? ARM::t2LDREXB : ARM::STREXB;
+    strOpc = isThumb2 ? ARM::t2STREXB : ARM::STREXB;
     break;
   case 2:
     ldrOpc = isThumb2 ? ARM::t2LDREXH : ARM::LDREXH;