Index: lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
===================================================================
--- lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
+++ lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
@@ -173,7 +173,8 @@
   // Unfortunately in MIPS both NOP and SLL will come in with Binary == 0
   // so we have to special check for them.
   unsigned Opcode = TmpInst.getOpcode();
-  if ((Opcode != Mips::NOP) && (Opcode != Mips::SLL) && !Binary)
+  if ((Opcode != Mips::NOP) && (Opcode != Mips::SLL) &&
+      (Opcode != Mips::SLL_MM) && !Binary)
     llvm_unreachable("unimplemented opcode in EncodeInstruction()");
 
   if (STI.getFeatureBits() & Mips::FeatureMicroMips) {
Index: lib/Target/Mips/MicroMipsInstrInfo.td
===================================================================
--- lib/Target/Mips/MicroMipsInstrInfo.td
+++ lib/Target/Mips/MicroMipsInstrInfo.td
@@ -697,4 +697,6 @@
 //===----------------------------------------------------------------------===//
 
   def : MipsInstAlias<"wait", (WAIT_MM 0x0), 1>;
+  def : MipsInstAlias<"nop", (SLL_MM ZERO, ZERO, 0), 1>;
+  def : MipsInstAlias<"nop", (MOVE16_MM ZERO, ZERO), 1>;
 }
Index: test/MC/Disassembler/Mips/micromips.txt
===================================================================
--- test/MC/Disassembler/Mips/micromips.txt
+++ test/MC/Disassembler/Mips/micromips.txt
@@ -331,6 +331,9 @@
 # CHECK: swm32 $16, $17, 8($4)
 0x20 0x44 0xd0 0x08
 
+# CHECK: nop
+0x00 0x00 0x00 0x00
+
 # CHECK: addu16 $6, $17, $4
 0x07 0x42
 
@@ -399,3 +402,6 @@
 
 # CHECK: addius5 $7, -2
 0x4c 0xfc
+
+# CHECK: nop
+0x0c 0x00
Index: test/MC/Disassembler/Mips/micromips_le.txt
===================================================================
--- test/MC/Disassembler/Mips/micromips_le.txt
+++ test/MC/Disassembler/Mips/micromips_le.txt
@@ -331,6 +331,9 @@
 # CHECK: swm32 $16, $17, 8($4)
 0x44 0x20 0x08 0xd0
 
+# CHECK: nop
+0x00 0x00 0x00 0x00
+
 # CHECK: addu16 $6, $17, $4
 0x42 0x07
 
@@ -399,3 +402,6 @@
 
 # CHECK: addius5 $7, -2
 0xfc 0x4c
+
+# CHECK: nop
+0x00 0x0c
Index: test/MC/Mips/micromips-16-bit-instructions.s
===================================================================
--- test/MC/Mips/micromips-16-bit-instructions.s
+++ test/MC/Mips/micromips-16-bit-instructions.s
@@ -42,7 +42,7 @@
 # CHECK-EL: jraddiusp 20            # encoding: [0x05,0x47]
 # CHECK-EL: nop                     # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EL: jalrs16 $9              # encoding: [0xe9,0x45]
-# CHECK-EL: move    $zero, $zero    # encoding: [0x00,0x0c]
+# CHECK-EL: nop                     # encoding: [0x00,0x0c]
 # CHECK-EL: jr16    $9              # encoding: [0x89,0x45]
 # CHECK-EL: nop                     # encoding: [0x00,0x00,0x00,0x00]
 #------------------------------------------------------------------------------
@@ -81,7 +81,7 @@
 # CHECK-EB: jraddiusp 20            # encoding: [0x47,0x05]
 # CHECK-EB: nop                     # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: jalrs16 $9              # encoding: [0x45,0xe9]
-# CHECK-EB: move    $zero, $zero    # encoding: [0x0c,0x00]
+# CHECK-EB: nop                     # encoding: [0x0c,0x00]
 # CHECK-EB: jr16    $9              # encoding: [0x45,0x89]
 # CHECK-EB: nop                     # encoding: [0x00,0x00,0x00,0x00]
 
Index: test/MC/Mips/micromips-branch-instructions.s
===================================================================
--- test/MC/Mips/micromips-branch-instructions.s
+++ test/MC/Mips/micromips-branch-instructions.s
@@ -30,9 +30,9 @@
 # CHECK-EL: bltz $6, 1332        # encoding: [0x06,0x40,0x9a,0x02]
 # CHECK-EL: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EL: bgezals $6, 1332     # encoding: [0x66,0x42,0x9a,0x02]
-# CHECK-EL: move $zero, $zero    # encoding: [0x00,0x0c]
+# CHECK-EL: nop                  # encoding: [0x00,0x0c]
 # CHECK-EL: bltzals $6, 1332     # encoding: [0x26,0x42,0x9a,0x02]
-# CHECK-EL: move $zero, $zero    # encoding: [0x00,0x0c]
+# CHECK-EL: nop                  # encoding: [0x00,0x0c]
 #------------------------------------------------------------------------------
 # Big endian
 #------------------------------------------------------------------------------
@@ -57,9 +57,9 @@
 # CHECK-EB: bltz $6, 1332        # encoding: [0x40,0x06,0x02,0x9a]
 # CHECK-EB: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: bgezals $6, 1332     # encoding: [0x42,0x66,0x02,0x9a]
-# CHECK-EB: move $zero, $zero    # encoding: [0x0c,0x00]
+# CHECK-EB: nop                  # encoding: [0x0c,0x00]
 # CHECK-EB: bltzals $6, 1332     # encoding: [0x42,0x26,0x02,0x9a]
-# CHECK-EB: move $zero, $zero    # encoding: [0x0c,0x00]
+# CHECK-EB: nop                  # encoding: [0x0c,0x00]
 
      b      1332
      beq    $9,$6,1332
Index: test/MC/Mips/micromips-jump-instructions.s
===================================================================
--- test/MC/Mips/micromips-jump-instructions.s
+++ test/MC/Mips/micromips-jump-instructions.s
@@ -20,9 +20,9 @@
 # CHECK-EL: jr $7       # encoding: [0x07,0x00,0x3c,0x0f]
 # CHECK-EL: nop         # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EL: jals 1328         # encoding: [0x00,0x74,0x98,0x02]
-# CHECK-EL: move $zero, $zero # encoding: [0x00,0x0c]
+# CHECK-EL: nop               # encoding: [0x00,0x0c]
 # CHECK-EL: jalrs $ra, $6     # encoding: [0xe6,0x03,0x3c,0x4f]
-# CHECK-EL: move $zero, $zero # encoding: [0x00,0x0c]
+# CHECK-EL: nop               # encoding: [0x00,0x0c]
 #------------------------------------------------------------------------------
 # Big endian
 #------------------------------------------------------------------------------
@@ -37,9 +37,9 @@
 # CHECK-EB: jr $7       # encoding: [0x00,0x07,0x0f,0x3c]
 # CHECK-EB: nop         # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: jals 1328         # encoding: [0x74,0x00,0x02,0x98]
-# CHECK-EB: move $zero, $zero # encoding: [0x0c,0x00]
+# CHECK-EB: nop               # encoding: [0x0c,0x00]
 # CHECK-EB: jalrs $ra, $6     # encoding: [0x03,0xe6,0x4f,0x3c]
-# CHECK-EB: move $zero, $zero # encoding: [0x0c,0x00]
+# CHECK-EB: nop               # encoding: [0x0c,0x00]
 
      j 1328
      jal 1328