Index: lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
===================================================================
--- lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
+++ lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
@@ -243,6 +243,11 @@
     return Kind == KindImmTLS;
   }
 
+  const ImmTLSOp getImmTLS() const {
+    assert(Kind == KindImmTLS && "Not a TLS immediate");
+    return ImmTLS;
+  }
+
   // Memory operands.
   bool isMem() const override {
     return Kind == KindMem;
@@ -623,8 +628,46 @@
     { MCK_U48Imm, MCK_BDAddr64Disp12, MCK_BDAddr64Disp12, MCK_AnyReg } }
 };
 
+static void printMCExpr(const MCExpr *E, raw_ostream &OS) {
+  if (!E) {
+    OS << "?";
+    return;
+  }
+  if (auto *CE = dyn_cast<MCConstantExpr>(E))
+    OS << "'" << *CE << "'";
+  else if (auto *UE = dyn_cast<MCUnaryExpr>(E))
+    OS << "'" << *UE << "'";
+  else if (auto *BE = dyn_cast<MCBinaryExpr>(E))
+    OS << "'" << *BE << "'";
+  else if (auto *SRE = dyn_cast<MCSymbolRefExpr>(E))
+    OS << "'" << *SRE << "'";
+  else
+    OS << "'" << *E << "'";
+}
+
 void SystemZOperand::print(raw_ostream &OS) const {
-  llvm_unreachable("Not implemented");
+  switch (Kind) {
+    break;
+  case KindToken:
+    OS << "'" << getToken() << "'";
+    break;
+  case KindReg:
+    OS << "'" << getReg() << "'";
+    break;
+  case KindImm:
+    printMCExpr(getImm(), OS);
+    break;
+  case KindImmTLS:
+    printMCExpr(getImmTLS().Imm, OS);
+    OS << ", ";
+    printMCExpr(getImmTLS().Sym, OS);
+    break;
+  default:
+  case KindMem:
+  case KindInvalid:
+    OS << "?";
+    break;
+  }
 }
 
 // Parse one register of the form %<prefix><number>.
Index: test/MC/SystemZ/asm-match.s
===================================================================
--- /dev/null
+++ test/MC/SystemZ/asm-match.s
@@ -0,0 +1,27 @@
+// REQUIRES: asserts
+// RUN: llvm-mc -triple s390x-linux-gnu -debug-only=asm-matcher %s 2>&1 | FileCheck %s
+//
+// Check that debug output gives some reasonable output.
+
+// CHECK: AsmMatcher:      found 1 encodings with mnemonic 'llill'
+// CHECK:   Trying to match opcode LLILL
+// CHECK:   Matching formal operand class MCK_GR64 against actual operand at index 1 ('138'): match success using generic matcher
+// CHECK:   Matching formal operand class MCK_U16Imm against actual operand at index 2 (0): match success using generic matcher
+// CHECK:   Matching formal operand class InvalidMatchClass against actual operand at index 3: actual operand index out of range Opcode result: complete match, selecting this opcode
+// CHECK: AsmMatcher:      found 1 encodings with mnemonic 'lgr'
+// CHECK:   Trying to match opcode LGR
+// CHECK:   Matching formal operand class MCK_GR64 against actual operand at index 1 ('139'): match success using generic matcher
+// CHECK:   Matching formal operand class MCK_GR64 against actual operand at index 2 ('138'): match success using generic matcher
+// CHECK:   Matching formal operand class InvalidMatchClass against actual operand at index 3: actual operand index out of range Opcode result: complete match, selecting this opcode
+// CHECK: AsmMatcher:      found 1 encodings with mnemonic 'j'
+// CHECK:   Trying to match opcode J
+// CHECK:    Matching formal operand class MCK_PCRel16 against actual operand at index 1 (.Ltmp0+2): match success using generic matcher
+// CHECK:   Matching formal operand class InvalidMatchClass against actual operand at index 2: actual operand index out of range Opcode result: complete match, selecting this opcode
+	
+.Ltmp0:
+	llill	%r0, 0
+	lgr	%r1, %r0
+	j	.Ltmp0+2
+        stmg    %r13, %r15, 104(%r15)
+        brasl   %r14, fun
+