Index: lib/Target/Mips/MipsSEInstrInfo.cpp
===================================================================
--- lib/Target/Mips/MipsSEInstrInfo.cpp
+++ lib/Target/Mips/MipsSEInstrInfo.cpp
@@ -446,6 +446,9 @@
   case Mips::PseudoMTLOHI_DSP:
     expandPseudoMTLoHi(MBB, MI, Mips::MTLO_DSP, Mips::MTHI_DSP, true);
     break;
+  case Mips::PseudoMTLOHI_MM:
+    expandPseudoMTLoHi(MBB, MI, Mips::MTLO_MM, Mips::MTHI_MM, false);
+    break;
   case Mips::PseudoCVT_S_W:
     expandCvtFPInt(MBB, MI, Mips::CVT_S_W, Mips::MTC1, false);
     break;
Index: test/CodeGen/Mips/micromips-pseudo-mtlohi-expand.ll
===================================================================
--- /dev/null
+++ test/CodeGen/Mips/micromips-pseudo-mtlohi-expand.ll
@@ -0,0 +1,90 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=mipsel-linux-gnu -mcpu=mips32r2 -mattr=+micromips -asm-show-inst < %s |\
+; RUN:   FileCheck %s -check-prefixes=MMR2
+; RUN: llc -mtriple=mipsel-linux-gnu -mcpu=mips32r2 -mattr=+dsp,+micromips -asm-show-inst < %s |\
+; RUN:   FileCheck %s -check-prefixes=MMR2-DSP
+; RUN: llc -mtriple=mipsel-linux-gnu -mcpu=mips32r6 -mattr=+micromips -asm-show-inst < %s |\
+; RUN:   FileCheck %s -check-prefixes=MMR6
+
+define i64 @test(i32 signext %a, i32 signext %b) {
+; MMR2-LABEL: test:
+; MMR2:       # %bb.0: # %entry
+; MMR2-NEXT:    li16 $2, 0 # <MCInst #1700 LI16_MM
+; MMR2-NEXT:    # <MCOperand Reg:321>
+; MMR2-NEXT:    # <MCOperand Imm:0>>
+; MMR2-NEXT:    li16 $3, 1 # <MCInst #1700 LI16_MM
+; MMR2-NEXT:    # <MCOperand Reg:322>
+; MMR2-NEXT:    # <MCOperand Imm:1>>
+; MMR2-NEXT:    mtlo $3 # <MCInst #2008 MTLO_MM
+; MMR2-NEXT:    # <MCOperand Reg:322>>
+; MMR2-NEXT:    mthi $2 # <MCInst #2001 MTHI_MM
+; MMR2-NEXT:    # <MCOperand Reg:321>>
+; MMR2-NEXT:    madd $4, $5 # <MCInst #1774 MADD
+; MMR2-NEXT:    # <MCOperand Reg:22>
+; MMR2-NEXT:    # <MCOperand Reg:23>>
+; MMR2-NEXT:    mflo16 $2 # <MCInst #1860 MFLO16_MM
+; MMR2-NEXT:    # <MCOperand Reg:321>>
+; MMR2-NEXT:    mfhi16 $3 # <MCInst #1854 MFHI16_MM
+; MMR2-NEXT:    # <MCOperand Reg:322>>
+; MMR2-NEXT:    jrc $ra # <MCInst #1632 JRC16_MM
+; MMR2-NEXT:    # <MCOperand Reg:19>>
+;
+; MMR2-DSP-LABEL: test:
+; MMR2-DSP:       # %bb.0: # %entry
+; MMR2-DSP-NEXT:    li16 $2, 0 # <MCInst #1700 LI16_MM
+; MMR2-DSP-NEXT:    # <MCOperand Reg:321>
+; MMR2-DSP-NEXT:    # <MCOperand Imm:0>>
+; MMR2-DSP-NEXT:    li16 $3, 1 # <MCInst #1700 LI16_MM
+; MMR2-DSP-NEXT:    # <MCOperand Reg:322>
+; MMR2-DSP-NEXT:    # <MCOperand Imm:1>>
+; MMR2-DSP-NEXT:    mtlo $3, $ac0 # <MCInst #2006 MTLO_DSP
+; MMR2-DSP-NEXT:    # <MCOperand Reg:291>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:322>>
+; MMR2-DSP-NEXT:    mthi $2, $ac0 # <MCInst #1999 MTHI_DSP
+; MMR2-DSP-NEXT:    # <MCOperand Reg:253>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:321>>
+; MMR2-DSP-NEXT:    madd $ac0, $4, $5 # <MCInst #1792 MADD_DSP
+; MMR2-DSP-NEXT:    # <MCOperand Reg:26>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:22>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:23>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:26>>
+; MMR2-DSP-NEXT:    mflo $2, $ac0 # <MCInst #1862 MFLO_DSP
+; MMR2-DSP-NEXT:    # <MCOperand Reg:321>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:26>>
+; MMR2-DSP-NEXT:    jr $ra # <MCInst #1639 JR_MM
+; MMR2-DSP-NEXT:    # <MCOperand Reg:19>>
+; MMR2-DSP-NEXT:    mfhi $3, $ac0 # <MCInst #1856 MFHI_DSP
+; MMR2-DSP-NEXT:    # <MCOperand Reg:322>
+; MMR2-DSP-NEXT:    # <MCOperand Reg:26>>
+;
+; MMR6-LABEL: test:
+; MMR6:       # %bb.0: # %entry
+; MMR6-NEXT:    mul $3, $4, $5 # <MCInst #2058 MUL_MMR6
+; MMR6-NEXT:    # <MCOperand Reg:322>
+; MMR6-NEXT:    # <MCOperand Reg:22>
+; MMR6-NEXT:    # <MCOperand Reg:23>>
+; MMR6-NEXT:    addiur2 $2, $3, 1 # <MCInst #559 ADDIUR2_MM
+; MMR6-NEXT:    # <MCOperand Reg:321>
+; MMR6-NEXT:    # <MCOperand Reg:322>
+; MMR6-NEXT:    # <MCOperand Imm:1>>
+; MMR6-NEXT:    sltu $3, $2, $3 # <MCInst #2398 SLTu_MM
+; MMR6-NEXT:    # <MCOperand Reg:322>
+; MMR6-NEXT:    # <MCOperand Reg:321>
+; MMR6-NEXT:    # <MCOperand Reg:322>>
+; MMR6-NEXT:    muh $4, $4, $5 # <MCInst #2019 MUH_MMR6
+; MMR6-NEXT:    # <MCOperand Reg:22>
+; MMR6-NEXT:    # <MCOperand Reg:22>
+; MMR6-NEXT:    # <MCOperand Reg:23>>
+; MMR6-NEXT:    addu16 $3, $4, $3 # <MCInst #592 ADDU16_MMR6
+; MMR6-NEXT:    # <MCOperand Reg:322>
+; MMR6-NEXT:    # <MCOperand Reg:22>
+; MMR6-NEXT:    # <MCOperand Reg:322>>
+; MMR6-NEXT:    jrc $ra # <MCInst #1632 JRC16_MM
+; MMR6-NEXT:    # <MCOperand Reg:19>>
+entry:
+  %conv = sext i32 %a to i64
+  %conv1 = sext i32 %b to i64
+  %mul = mul nsw i64 %conv, %conv1
+  %add = add nsw i64 %mul, 1
+  ret i64 %add
+}