[SystemZ] Add truncating high-word stores (STCH and STHH)

llvm-svn: 191743
diff --git a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
index 7cbb4f7..1992993 100644
--- a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
@@ -826,6 +826,14 @@
     expandRXYPseudo(MI, SystemZ::L, SystemZ::LFH);
     return true;
 
+  case SystemZ::STCMux:
+    expandRXYPseudo(MI, SystemZ::STC, SystemZ::STCH);
+    return true;
+
+  case SystemZ::STHMux:
+    expandRXYPseudo(MI, SystemZ::STH, SystemZ::STHH);
+    return true;
+
   case SystemZ::STMux:
     expandRXYPseudo(MI, SystemZ::ST, SystemZ::STFH);
     return true;