Index: lib/Target/Mips/MicroMips32r6InstrFormats.td
===================================================================
--- lib/Target/Mips/MicroMips32r6InstrFormats.td
+++ lib/Target/Mips/MicroMips32r6InstrFormats.td
@@ -203,20 +203,6 @@
   let Inst{15-0}  = offset;
 }
 
-class SIGN_EXTEND_FM_MMR6<string instr_asm, bits<10> funct>
-    : MMR6Arch<instr_asm> {
-  bits<5> rd;
-  bits<5> rt;
-
-  bits<32> Inst;
-
-  let Inst{31-26} = 0b000000;
-  let Inst{25-21} = rd;
-  let Inst{20-16} = rt;
-  let Inst{15-6}  = funct;
-  let Inst{5-0}   = 0b111100;
-}
-
 class PCREL19_FM_MMR6<bits<2> funct> : MipsR6Inst {
   bits<5> rt;
   bits<19> imm;
Index: lib/Target/Mips/MicroMips32r6InstrInfo.td
===================================================================
--- lib/Target/Mips/MicroMips32r6InstrInfo.td
+++ lib/Target/Mips/MicroMips32r6InstrInfo.td
@@ -136,8 +136,6 @@
 class ORI_MMR6_ENC : ADDI_FM_MMR6<"ori", 0x14>;
 class PREF_MMR6_ENC : CACHE_PREF_FM_MMR6<0b011000, 0b0010>;
 class SB16_MMR6_ENC : LOAD_STORE_FM_MM16<0x22>;
-class SEB_MMR6_ENC : SIGN_EXTEND_FM_MMR6<"seb", 0b0010101100>;
-class SEH_MMR6_ENC : SIGN_EXTEND_FM_MMR6<"seh", 0b0011101100>;
 class SELEQZ_MMR6_ENC : POOL32A_FM_MMR6<0b0101000000>;
 class SELNEZ_MMR6_ENC : POOL32A_FM_MMR6<0b0110000000>;
 class SH16_MMR6_ENC : LOAD_STORE_FM_MM16<0x2a>;
@@ -529,8 +527,6 @@
 
 class AUI_MMR6_DESC : AUI_MMR6_DESC_BASE<"aui", GPR32Opnd, II_AUI>;
 
-class SEB_MMR6_DESC : SignExtInReg<"seb", i8, GPR32Opnd, II_SEB>;
-class SEH_MMR6_DESC : SignExtInReg<"seh", i16, GPR32Opnd, II_SEH>;
 class ALUIPC_MMR6_DESC_BASE<string instr_asm, RegisterOperand GPROpnd,
                             InstrItinClass Itin> : MMR6Arch<instr_asm> {
   dag OutOperandList = (outs GPROpnd:$rt);
@@ -1382,8 +1378,6 @@
 def ORI_MMR6 : StdMMR6Rel, ORI_MMR6_DESC, ORI_MMR6_ENC, ISA_MICROMIPS32R6;
 def PREF_MMR6 : R6MMR6Rel, PREF_MMR6_ENC, PREF_MMR6_DESC, ISA_MICROMIPS32R6;
 def SB16_MMR6 : StdMMR6Rel, SB16_MMR6_DESC, SB16_MMR6_ENC, ISA_MICROMIPS32R6;
-def SEB_MMR6 : StdMMR6Rel, SEB_MMR6_DESC, SEB_MMR6_ENC, ISA_MICROMIPS32R6;
-def SEH_MMR6 : StdMMR6Rel, SEH_MMR6_DESC, SEH_MMR6_ENC, ISA_MICROMIPS32R6;
 def SELEQZ_MMR6 : R6MMR6Rel, SELEQZ_MMR6_ENC, SELEQZ_MMR6_DESC,
                   ISA_MICROMIPS32R6;
 def SELNEZ_MMR6 : R6MMR6Rel, SELNEZ_MMR6_ENC, SELNEZ_MMR6_DESC,
@@ -1658,10 +1652,6 @@
 def : MipsInstAlias<"not $rt, $rs",
                     (NOR_MMR6 GPR32Opnd:$rt, GPR32Opnd:$rs, ZERO), 0>,
                     ISA_MICROMIPS32R6;
-def : MipsInstAlias<"seh $rd", (SEH_MMR6 GPR32Opnd:$rd, GPR32Opnd:$rd), 0>,
-                    ISA_MICROMIPS32R6;
-def : MipsInstAlias<"seb $rd", (SEB_MMR6 GPR32Opnd:$rd, GPR32Opnd:$rd), 0>,
-                    ISA_MICROMIPS32R6;
 def : MipsInstAlias<"lapc $rd, $imm",
                     (ADDIUPC_MMR6 GPR32Opnd:$rd, simm19_lsl2:$imm)>,
                     ISA_MICROMIPS32R6;
Index: lib/Target/Mips/MicroMipsInstrInfo.td
===================================================================
--- lib/Target/Mips/MicroMipsInstrInfo.td
+++ lib/Target/Mips/MicroMipsInstrInfo.td
@@ -902,9 +902,9 @@
 
   /// Sign Ext In Register Instructions.
   def SEB_MM : MMRel, SignExtInReg<"seb", i8, GPR32Opnd, II_SEB>,
-               SEB_FM_MM<0x0ac>, ISA_MIPS32R2;
+               SEB_FM_MM<0x0ac>, ISA_MICROMIPS;
   def SEH_MM : MMRel, SignExtInReg<"seh", i16, GPR32Opnd, II_SEH>,
-               SEB_FM_MM<0x0ec>, ISA_MIPS32R2;
+               SEB_FM_MM<0x0ec>, ISA_MICROMIPS;
 
   /// Word Swap Bytes Within Halfwords
   def WSBH_MM : MMRel, SubwordSwap<"wsbh", GPR32Opnd, II_WSBH>,
@@ -1263,9 +1263,9 @@
                       (BEQ_MM GPR32Opnd:$rs, ZERO, brtarget:$offset), 0>,
         ISA_MICROMIPS;
   def : MipsInstAlias<"seh $rd", (SEH_MM GPR32Opnd:$rd, GPR32Opnd:$rd), 0>,
-                     ISA_MIPS32R2_NOT_32R6_64R6;
+                     ISA_MICROMIPS;
   def : MipsInstAlias<"seb $rd", (SEB_MM GPR32Opnd:$rd, GPR32Opnd:$rd), 0>,
-                     ISA_MIPS32R2_NOT_32R6_64R6;
+                     ISA_MICROMIPS;
   def : MipsInstAlias<"break", (BREAK_MM 0, 0), 1>, ISA_MICROMIPS;
   def : MipsInstAlias<"break $imm", (BREAK_MM uimm10:$imm, 0), 1>,
         ISA_MICROMIPS;
Index: lib/Target/Mips/MipsInstrInfo.td
===================================================================
--- lib/Target/Mips/MipsInstrInfo.td
+++ lib/Target/Mips/MipsInstrInfo.td
@@ -2240,13 +2240,13 @@
            ISA_MIPS1_NOT_32R6_64R6;
 def MFLO : MMRel, MoveFromLOHI<"mflo", GPR32Opnd, AC0>, MFLO_FM<0x12>,
            ISA_MIPS1_NOT_32R6_64R6;
-}
 
 /// Sign Ext In Register Instructions.
 def SEB : MMRel, StdMMR6Rel, SignExtInReg<"seb", i8, GPR32Opnd, II_SEB>,
           SEB_FM<0x10, 0x20>, ISA_MIPS32R2;
 def SEH : MMRel, StdMMR6Rel, SignExtInReg<"seh", i16, GPR32Opnd, II_SEH>,
           SEB_FM<0x18, 0x20>, ISA_MIPS32R2;
+}
 
 /// Count Leading
 def CLZ : MMRel, CountLeading0<"clz", GPR32Opnd, II_CLZ>, CLO_FM<0x20>,
Index: test/MC/Mips/micromips/valid.s
===================================================================
--- test/MC/Mips/micromips/valid.s
+++ test/MC/Mips/micromips/valid.s
@@ -144,9 +144,13 @@
 clz $9, $6                  # CHECK: clz $9, $6             # encoding: [0x01,0x26,0x5b,0x3c]
 clo $9, $6                  # CHECK: clo $9, $6             # encoding: [0x01,0x26,0x4b,0x3c]
 seb $9, $6                  # CHECK: seb $9, $6             # encoding: [0x01,0x26,0x2b,0x3c]
+                            # CHECK-NEXT:                   # <MCInst #{{[0-9]+}} SEB_MM
 seb $9                      # CHECK: seb $9, $9             # encoding: [0x01,0x29,0x2b,0x3c]
+                            # CHECK-NEXT:                   # <MCInst #{{[0-9]+}} SEB_MM
 seh $9, $6                  # CHECK: seh $9, $6             # encoding: [0x01,0x26,0x3b,0x3c]
+                            # CHECK-NEXT:                   # <MCInst #{{[0-9]+}} SEH_MM
 seh $9                      # CHECK: seh $9, $9             # encoding: [0x01,0x29,0x3b,0x3c]
+                            # CHECK-NEXT:                   # <MCInst #{{[0-9]+}} SEH_MM
 wsbh $9, $6                 # CHECK: wsbh $9, $6            # encoding: [0x01,0x26,0x7b,0x3c]
 ext $9, $6, 3, 7            # CHECK: ext $9, $6, 3, 7       # encoding: [0x01,0x26,0x30,0xec]
 ins $9, $6, 3, 7            # CHECK: ins $9, $6, 3, 7       # encoding: [0x01,0x26,0x48,0xcc]
Index: test/MC/Mips/mips32r2/valid.s
===================================================================
--- test/MC/Mips/mips32r2/valid.s
+++ test/MC/Mips/mips32r2/valid.s
@@ -235,9 +235,13 @@
         sdc2      $20,23157($s2)       # CHECK: sdc2 $20, 23157($18)   # encoding: [0xfa,0x54,0x5a,0x75]
         sdxc1     $f11,$10($14)
         seb       $25, $15             # CHECK: seb $25, $15           # encoding: [0x7c,0x0f,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seb       $25                  # CHECK: seb $25, $25           # encoding: [0x7c,0x19,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seh       $3, $12              # CHECK: seh $3, $12            # encoding: [0x7c,0x0c,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         seh       $3                   # CHECK: seh $3, $3             # encoding: [0x7c,0x03,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         sgt       $4, $5               # CHECK: slt $4, $5, $4         # encoding: [0x00,0xa4,0x20,0x2a]
         sgt       $4, $5, $6           # CHECK: slt $4, $6, $5         # encoding: [0x00,0xc5,0x20,0x2a]
         sgtu      $4, $5               # CHECK: sltu $4, $5, $4        # encoding: [0x00,0xa4,0x20,0x2b]
Index: test/MC/Mips/mips32r3/valid.s
===================================================================
--- test/MC/Mips/mips32r3/valid.s
+++ test/MC/Mips/mips32r3/valid.s
@@ -235,9 +235,13 @@
         sdc2      $20,23157($s2)       # CHECK: sdc2 $20, 23157($18)   # encoding: [0xfa,0x54,0x5a,0x75]
         sdxc1     $f11,$10($14)
         seb       $25, $15             # CHECK: seb $25, $15           # encoding: [0x7c,0x0f,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seb       $25                  # CHECK: seb $25, $25           # encoding: [0x7c,0x19,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seh       $3, $12              # CHECK: seh $3, $12            # encoding: [0x7c,0x0c,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         seh       $3                   # CHECK: seh $3, $3             # encoding: [0x7c,0x03,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         sgt       $4, $5               # CHECK: slt $4, $5, $4         # encoding: [0x00,0xa4,0x20,0x2a]
         sgt       $4, $5, $6           # CHECK: slt $4, $6, $5         # encoding: [0x00,0xc5,0x20,0x2a]
         sgtu      $4, $5               # CHECK: sltu $4, $5, $4        # encoding: [0x00,0xa4,0x20,0x2b]
Index: test/MC/Mips/mips32r5/valid.s
===================================================================
--- test/MC/Mips/mips32r5/valid.s
+++ test/MC/Mips/mips32r5/valid.s
@@ -236,9 +236,13 @@
         sdc2      $20,23157($s2)       # CHECK: sdc2 $20, 23157($18)   # encoding: [0xfa,0x54,0x5a,0x75]
         sdxc1     $f11,$10($14)
         seb       $25, $15             # CHECK: seb $25, $15           # encoding: [0x7c,0x0f,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seb       $25                  # CHECK: seb $25, $25           # encoding: [0x7c,0x19,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seh       $3, $12              # CHECK: seh $3, $12            # encoding: [0x7c,0x0c,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         seh       $3                   # CHECK: seh $3, $3             # encoding: [0x7c,0x03,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         sgt       $4, $5               # CHECK: slt $4, $5, $4         # encoding: [0x00,0xa4,0x20,0x2a]
         sgt       $4, $5, $6           # CHECK: slt $4, $6, $5         # encoding: [0x00,0xc5,0x20,0x2a]
         sgtu      $4, $5               # CHECK: sltu $4, $5, $4        # encoding: [0x00,0xa4,0x20,0x2b]
Index: test/MC/Mips/mips32r6/valid.s
===================================================================
--- test/MC/Mips/mips32r6/valid.s
+++ test/MC/Mips/mips32r6/valid.s
@@ -201,9 +201,13 @@
         rsqrt.s $f0,$f4          # CHECK: rsqrt.s $f0, $f4       # encoding: [0x46,0x00,0x20,0x16]
         rsqrt.d $f2,$f6          # CHECK: rsqrt.d $f2, $f6       # encoding: [0x46,0x20,0x30,0x96]
         seb       $25, $15       # CHECK: seb $25, $15           # encoding: [0x7c,0x0f,0xcc,0x20]
+                                 # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seb       $25            # CHECK: seb $25, $25           # encoding: [0x7c,0x19,0xcc,0x20]
+                                 # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seh       $3, $12        # CHECK: seh $3, $12            # encoding: [0x7c,0x0c,0x1e,0x20]
+                                 # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         seh       $3             # CHECK: seh $3, $3             # encoding: [0x7c,0x03,0x1e,0x20]
+                                 # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         sgt     $4, $5           # CHECK: slt $4, $5, $4         # encoding: [0x00,0xa4,0x20,0x2a]
         sgt     $4, $5, $6       # CHECK: slt $4, $6, $5         # encoding: [0x00,0xc5,0x20,0x2a]
         sgtu    $4, $5           # CHECK: sltu $4, $5, $4        # encoding: [0x00,0xa4,0x20,0x2b]
Index: test/MC/Mips/mips64r2/valid.s
===================================================================
--- test/MC/Mips/mips64r2/valid.s
+++ test/MC/Mips/mips64r2/valid.s
@@ -305,9 +305,13 @@
         sdr       $11,-20423($12)
         sdxc1     $f11,$10($14)
         seb       $25, $15             # CHECK: seb $25, $15           # encoding: [0x7c,0x0f,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seb       $25                  # CHECK: seb $25, $25           # encoding: [0x7c,0x19,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seh       $3, $12              # CHECK: seh $3, $12            # encoding: [0x7c,0x0c,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         seh       $3                   # CHECK: seh $3, $3             # encoding: [0x7c,0x03,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         sgt       $4, $5               # CHECK: slt $4, $5, $4         # encoding: [0x00,0xa4,0x20,0x2a]
         sgt       $4, $5, $6           # CHECK: slt $4, $6, $5         # encoding: [0x00,0xc5,0x20,0x2a]
         sgtu      $4, $5               # CHECK: sltu $4, $5, $4        # encoding: [0x00,0xa4,0x20,0x2b]
Index: test/MC/Mips/mips64r3/valid.s
===================================================================
--- test/MC/Mips/mips64r3/valid.s
+++ test/MC/Mips/mips64r3/valid.s
@@ -299,9 +299,13 @@
         sdr       $11,-20423($12)
         sdxc1     $f11,$10($14)
         seb       $25, $15             # CHECK: seb $25, $15           # encoding: [0x7c,0x0f,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seb       $25                  # CHECK: seb $25, $25           # encoding: [0x7c,0x19,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seh       $3, $12              # CHECK: seh $3, $12            # encoding: [0x7c,0x0c,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         seh       $3                   # CHECK: seh $3, $3             # encoding: [0x7c,0x03,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         sh        $14,-6704($15)
         sll       $a3,18               # CHECK: sll $7, $7, 18         # encoding: [0x00,0x07,0x3c,0x80]
         sll       $a3,$zero,18         # CHECK: sll $7, $zero, 18      # encoding: [0x00,0x00,0x3c,0x80]
Index: test/MC/Mips/mips64r5/valid.s
===================================================================
--- test/MC/Mips/mips64r5/valid.s
+++ test/MC/Mips/mips64r5/valid.s
@@ -300,9 +300,13 @@
         sdr       $11,-20423($12)
         sdxc1     $f11,$10($14)
         seb       $25, $15             # CHECK: seb $25, $15           # encoding: [0x7c,0x0f,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seb       $25                  # CHECK: seb $25, $25           # encoding: [0x7c,0x19,0xcc,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
         seh       $3, $12              # CHECK: seh $3, $12            # encoding: [0x7c,0x0c,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         seh       $3                   # CHECK: seh $3, $3             # encoding: [0x7c,0x03,0x1e,0x20]
+                                       # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         sgt       $4, $5               # CHECK: slt $4, $5, $4         # encoding: [0x00,0xa4,0x20,0x2a]
         sgt       $4, $5, $6           # CHECK: slt $4, $6, $5         # encoding: [0x00,0xc5,0x20,0x2a]
         sgtu      $4, $5               # CHECK: sltu $4, $5, $4        # encoding: [0x00,0xa4,0x20,0x2b]
Index: test/MC/Mips/mips64r6/valid.s
===================================================================
--- test/MC/Mips/mips64r6/valid.s
+++ test/MC/Mips/mips64r6/valid.s
@@ -239,10 +239,14 @@
         selnez  $2,$3,$4         # CHECK: selnez $2, $3, $4 # encoding: [0x00,0x64,0x10,0x37]
         selnez.d $f0, $f2, $f4   # CHECK: selnez.d $f0, $f2, $f4 # encoding: [0x46,0x24,0x10,0x17]
         selnez.s $f0, $f2, $f4   # CHECK: selnez.s $f0, $f2, $f4 # encoding: [0x46,0x04,0x10,0x17]
-        seb       $25, $15       # CHECK: seb $25, $15           # encoding: [0x7c,0x0f,0xcc,0x20]
-        seb       $25            # CHECK: seb $25, $25           # encoding: [0x7c,0x19,0xcc,0x20]
-        seh       $3, $12        # CHECK: seh $3, $12            # encoding: [0x7c,0x0c,0x1e,0x20]
-        seh       $3             # CHECK: seh $3, $3             # encoding: [0x7c,0x03,0x1e,0x20]
+        seb     $25, $15         # CHECK: seb $25, $15           # encoding: [0x7c,0x0f,0xcc,0x20]
+                                 # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
+        seb     $25              # CHECK: seb $25, $25           # encoding: [0x7c,0x19,0xcc,0x20]
+                                 # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEB_MM
+        seh     $3, $12          # CHECK: seh $3, $12            # encoding: [0x7c,0x0c,0x1e,0x20]
+                                 # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
+        seh     $3               # CHECK: seh $3, $3             # encoding: [0x7c,0x03,0x1e,0x20]
+                                 # CHECK-NOT:                    # <MCInst #{{[0-9]+}} SEH_MM
         sgt     $4, $5           # CHECK: slt $4, $5, $4         # encoding: [0x00,0xa4,0x20,0x2a]
         sgt     $4, $5, $6       # CHECK: slt $4, $6, $5         # encoding: [0x00,0xc5,0x20,0x2a]
         sgtu    $4, $5           # CHECK: sltu $4, $5, $4        # encoding: [0x00,0xa4,0x20,0x2b]