Index: include/llvm/IR/InlineAsm.h
===================================================================
--- include/llvm/IR/InlineAsm.h
+++ include/llvm/IR/InlineAsm.h
@@ -243,6 +243,9 @@
     Constraint_o,
     Constraint_v,
     Constraint_Q,
+    Constraint_R,
+    Constraint_S,
+    Constraint_T,
     Constraint_Um,
     Constraint_Un,
     Constraint_Uq,
Index: lib/Target/SystemZ/SystemZISelDAGToDAG.cpp
===================================================================
--- lib/Target/SystemZ/SystemZISelDAGToDAG.cpp
+++ lib/Target/SystemZ/SystemZISelDAGToDAG.cpp
@@ -1131,17 +1131,26 @@
 SelectInlineAsmMemoryOperand(const SDValue &Op,
                              unsigned ConstraintID,
                              std::vector<SDValue> &OutOps) {
-  assert(ConstraintID == InlineAsm::Constraint_m &&
-         "Unexpected constraint code");
-  // Accept addresses with short displacements, which are compatible
-  // with Q, R, S and T.  But keep the index operand for future expansion.
-  SDValue Base, Disp, Index;
-  if (!selectBDXAddr(SystemZAddressingMode::FormBD,
-                     SystemZAddressingMode::Disp12Only,
-                     Op, Base, Disp, Index))
-    return true;
-  OutOps.push_back(Base);
-  OutOps.push_back(Disp);
-  OutOps.push_back(Index);
-  return false;
+  switch(ConstraintID) {
+  default:
+    llvm_unreachable("Unexpected asm memory constraint");
+  case InlineAsm::Constraint_m:
+  case InlineAsm::Constraint_Q:
+  case InlineAsm::Constraint_R:
+  case InlineAsm::Constraint_S:
+  case InlineAsm::Constraint_T:
+    // Accept addresses with short displacements, which are compatible
+    // with Q, R, S and T.  But keep the index operand for future expansion.
+    SDValue Base, Disp, Index;
+    if (selectBDXAddr(SystemZAddressingMode::FormBD,
+                      SystemZAddressingMode::Disp12Only,
+                      Op, Base, Disp, Index)) {
+      OutOps.push_back(Base);
+      OutOps.push_back(Disp);
+      OutOps.push_back(Index);
+      return false;
+    }
+    break;
+  }
+  return true;
 }
Index: lib/Target/SystemZ/SystemZISelLowering.h
===================================================================
--- lib/Target/SystemZ/SystemZISelLowering.h
+++ lib/Target/SystemZ/SystemZISelLowering.h
@@ -236,8 +236,21 @@
 
   unsigned getInlineAsmMemConstraint(
       const std::string ConstraintCode) const override {
-    // FIXME: Map different constraints differently.
-    return InlineAsm::Constraint_m;
+    if (ConstraintCode.size() == 1) {
+      switch(ConstraintCode[0]) {
+      default:
+        break;
+      case 'Q':
+        return InlineAsm::Constraint_Q;
+      case 'R':
+        return InlineAsm::Constraint_R;
+      case 'S':
+        return InlineAsm::Constraint_S;
+      case 'T':
+        return InlineAsm::Constraint_T;
+      }
+    }
+    return TargetLowering::getInlineAsmMemConstraint(ConstraintCode);
   }
 
   MachineBasicBlock *EmitInstrWithCustomInserter(MachineInstr *MI,