Index: lib/Target/AMDGPU/AMDGPUInstructionSelector.h
===================================================================
--- lib/Target/AMDGPU/AMDGPUInstructionSelector.h
+++ lib/Target/AMDGPU/AMDGPUInstructionSelector.h
@@ -76,6 +76,7 @@
   bool selectG_ADD(MachineInstr &I) const;
   bool selectG_EXTRACT(MachineInstr &I) const;
   bool selectG_MERGE_VALUES(MachineInstr &I) const;
+  bool selectG_UNMERGE_VALUES(MachineInstr &I) const;
   bool selectG_GEP(MachineInstr &I) const;
   bool selectG_IMPLICIT_DEF(MachineInstr &I) const;
   bool selectG_INSERT(MachineInstr &I) const;
Index: lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
+++ lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
@@ -361,6 +361,51 @@
   return true;
 }
 
+bool AMDGPUInstructionSelector::selectG_UNMERGE_VALUES(MachineInstr &MI) const {
+  MachineBasicBlock *BB = MI.getParent();
+  MachineFunction *MF = BB->getParent();
+  MachineRegisterInfo &MRI = MF->getRegInfo();
+  const int NumDst = MI.getNumOperands() - 1;
+
+  MachineOperand &Src = MI.getOperand(NumDst);
+
+  Register SrcReg = Src.getReg();
+  Register DstReg0 = MI.getOperand(0).getReg();
+  LLT DstTy = MRI.getType(DstReg0);
+  LLT SrcTy = MRI.getType(SrcReg);
+
+  const unsigned DstSize = DstTy.getSizeInBits();
+  const unsigned SrcSize = SrcTy.getSizeInBits();
+  const DebugLoc &DL = MI.getDebugLoc();
+  const RegisterBank *SrcBank = RBI.getRegBank(SrcReg, MRI, TRI);
+
+  const TargetRegisterClass *SrcRC =
+    TRI.getRegClassForSizeOnBank(SrcSize, *SrcBank, MRI);
+  assert(SrcRC);
+  if (!RBI.constrainGenericRegister(SrcReg, *SrcRC, MRI))
+    return false;
+
+  const unsigned SrcFlags = getUndefRegState(Src.isUndef());
+
+  // Note we could have mixed SGPR and VGPR destination banks for an SGPR
+  // source, and this relies on the fact that the same subregister indices are
+  // used for both.
+  ArrayRef<int16_t> SubRegs = TRI.getRegSplitParts(SrcRC, DstSize / 8);
+  for (int I = 0, E = NumDst; I != E; ++I) {
+    MachineOperand &Dst = MI.getOperand(I);
+    BuildMI(*BB, &MI, DL, TII.get(TargetOpcode::COPY), Dst.getReg())
+      .addReg(SrcReg, SrcFlags, SubRegs[I]);
+
+    const TargetRegisterClass *DstRC =
+      TRI.getConstrainedRegClassForOperand(Dst, MRI);
+    if (DstRC && !RBI.constrainGenericRegister(Dst.getReg(), *DstRC, MRI))
+      return false;
+  }
+
+  MI.eraseFromParent();
+  return true;
+}
+
 bool AMDGPUInstructionSelector::selectG_GEP(MachineInstr &I) const {
   return selectG_ADD(I);
 }
@@ -1184,6 +1229,8 @@
   case TargetOpcode::G_MERGE_VALUES:
   case TargetOpcode::G_CONCAT_VECTORS:
     return selectG_MERGE_VALUES(I);
+  case TargetOpcode::G_UNMERGE_VALUES:
+    return selectG_UNMERGE_VALUES(I);
   case TargetOpcode::G_GEP:
     return selectG_GEP(I);
   case TargetOpcode::G_IMPLICIT_DEF:
Index: test/CodeGen/AMDGPU/GlobalISel/inst-select-unmerge-values.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AMDGPU/GlobalISel/inst-select-unmerge-values.mir
@@ -0,0 +1,217 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=amdgcn-mesa-mesa3d -mcpu=tahiti -run-pass=instruction-select -global-isel-abort=2 -pass-remarks-missed='gisel*'  -o - %s 2> %t | FileCheck -check-prefix=GCN  %s
+# RUN: FileCheck -check-prefix=ERR %s < %t
+
+# ERR-NOT: remark:
+# ERR: remark: <unknown>:0:0: VReg has no regclass after selection: %3:sgpr(s192) = REG_SEQUENCE %0:sreg_64_xexec(s64), %subreg.sub0_sub1, %1:sreg_64_xexec(s64), %subreg.sub2_sub3, %2:sreg_64_xexec(s64), %subreg.sub4_sub5 (in function: test_merge_values_s_s192_s_s64_s_s64_s_s64)
+# ERR-NEXT: remark: <unknown>:0:0: VReg has no regclass after selection: %3:vgpr(s192) = REG_SEQUENCE %0:vreg_64(s64), %subreg.sub0_sub1, %1:vreg_64(s64), %subreg.sub2_sub3, %2:vreg_64(s64), %subreg.sub4_sub5 (in function: test_merge_values_v_s192_v_s64_v_s64_v_s64)
+# ERR-NOT: remark:
+
+---
+name: test_unmerge_values_v_s32_v_s32_v_s64
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $vgpr0_vgpr1
+
+    ; GCN-LABEL: name: test_unmerge_values_v_s32_v_s32_v_s64
+    ; GCN: liveins: $vgpr0_vgpr1
+    ; GCN: [[COPY:%[0-9]+]]:vreg_64 = COPY $vgpr0_vgpr1
+    ; GCN: [[COPY1:%[0-9]+]]:vgpr_32 = COPY [[COPY]].sub0
+    ; GCN: [[COPY2:%[0-9]+]]:vgpr_32 = COPY [[COPY]].sub1
+    ; GCN: S_ENDPGM 0, implicit [[COPY1]], implicit [[COPY2]]
+    %0:vgpr(s64) = COPY $vgpr0_vgpr1
+    %1:vgpr(s32), %2:vgpr(s32) = G_UNMERGE_VALUES %0
+    S_ENDPGM 0, implicit %1, implicit %2
+...
+
+---
+name: test_unmerge_values_s_s32_s_s32_s_s64
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0_sgpr1
+
+    ; GCN-LABEL: name: test_unmerge_values_s_s32_s_s32_s_s64
+    ; GCN: liveins: $sgpr0_sgpr1
+    ; GCN: [[COPY:%[0-9]+]]:sreg_64_xexec = COPY $sgpr0_sgpr1
+    ; GCN: [[COPY1:%[0-9]+]]:sreg_32_xm0 = COPY [[COPY]].sub0
+    ; GCN: [[COPY2:%[0-9]+]]:sreg_32_xm0 = COPY [[COPY]].sub1
+    ; GCN: S_ENDPGM 0, implicit [[COPY1]], implicit [[COPY2]]
+    %0:sgpr(s64) = COPY $sgpr0_sgpr1
+    %1:sgpr(s32), %2:sgpr(s32) = G_UNMERGE_VALUES %0
+    S_ENDPGM 0, implicit %1, implicit %2
+...
+
+---
+name: test_unmerge_values_v_s32_s_s32_s_s64
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0_sgpr1
+
+    ; GCN-LABEL: name: test_unmerge_values_v_s32_s_s32_s_s64
+    ; GCN: liveins: $sgpr0_sgpr1
+    ; GCN: [[COPY:%[0-9]+]]:sreg_64_xexec = COPY $sgpr0_sgpr1
+    ; GCN: [[COPY1:%[0-9]+]]:vgpr_32 = COPY [[COPY]].sub0
+    ; GCN: [[COPY2:%[0-9]+]]:sreg_32_xm0 = COPY [[COPY]].sub1
+    ; GCN: S_ENDPGM 0, implicit [[COPY1]], implicit [[COPY2]]
+    %0:sgpr(s64) = COPY $sgpr0_sgpr1
+    %1:vgpr(s32), %2:sgpr(s32) = G_UNMERGE_VALUES %0
+    S_ENDPGM 0, implicit %1, implicit %2
+...
+
+---
+name: test_unmerge_values_s_s32_v_s32_s_s64
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0_sgpr1
+
+    ; GCN-LABEL: name: test_unmerge_values_s_s32_v_s32_s_s64
+    ; GCN: liveins: $sgpr0_sgpr1
+    ; GCN: [[COPY:%[0-9]+]]:sreg_64_xexec = COPY $sgpr0_sgpr1
+    ; GCN: [[COPY1:%[0-9]+]]:sreg_32_xm0 = COPY [[COPY]].sub0
+    ; GCN: [[COPY2:%[0-9]+]]:vgpr_32 = COPY [[COPY]].sub1
+    ; GCN: S_ENDPGM 0, implicit [[COPY1]], implicit [[COPY2]]
+    %0:sgpr(s64) = COPY $sgpr0_sgpr1
+    %1:sgpr(s32), %2:vgpr(s32) = G_UNMERGE_VALUES %0
+    S_ENDPGM 0, implicit %1, implicit %2
+...
+
+---
+name: test_unmerge_values_s_s32_v_s32_s_s64_undef_src
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+
+    ; GCN-LABEL: name: test_unmerge_values_s_s32_v_s32_s_s64_undef_src
+    ; GCN: [[COPY:%[0-9]+]]:sreg_32_xm0 = COPY undef %2.sub0:sreg_64_xexec
+    ; GCN: [[COPY1:%[0-9]+]]:vgpr_32 = COPY undef %2.sub1:sreg_64_xexec
+    ; GCN: S_ENDPGM 0, implicit [[COPY]], implicit [[COPY1]]
+    %1:sgpr(s32), %2:vgpr(s32) = G_UNMERGE_VALUES undef %0:sgpr(s64)
+    S_ENDPGM 0, implicit %1, implicit %2
+...
+
+---
+name: test_unmerge_values_s_s32_s_s32_s32_s_s96
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0_sgpr1_sgpr2
+
+    ; GCN-LABEL: name: test_unmerge_values_s_s32_s_s32_s32_s_s96
+    ; GCN: liveins: $sgpr0_sgpr1_sgpr2
+    ; GCN: [[COPY:%[0-9]+]]:sreg_96 = COPY $sgpr0_sgpr1_sgpr2
+    ; GCN: [[COPY1:%[0-9]+]]:sreg_32_xm0 = COPY [[COPY]].sub0
+    ; GCN: [[COPY2:%[0-9]+]]:sreg_32_xm0 = COPY [[COPY]].sub1
+    ; GCN: [[COPY3:%[0-9]+]]:sreg_32_xm0 = COPY [[COPY]].sub2
+    ; GCN: S_ENDPGM 0, implicit [[COPY1]], implicit [[COPY2]], implicit [[COPY3]]
+    %0:sgpr(s96) = COPY $sgpr0_sgpr1_sgpr2
+    %1:sgpr(s32), %2:sgpr(s32), %3:sgpr(s32) = G_UNMERGE_VALUES %0
+    S_ENDPGM 0, implicit %1, implicit %2, implicit %3
+...
+
+---
+name: test_unmerge_values_s_s32_s_s32_s32_s_s32_s_s128
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0_sgpr1_sgpr2_sgpr3
+
+    ; GCN-LABEL: name: test_unmerge_values_s_s32_s_s32_s32_s_s32_s_s128
+    ; GCN: liveins: $sgpr0_sgpr1_sgpr2_sgpr3
+    ; GCN: [[COPY:%[0-9]+]]:sreg_128 = COPY $sgpr0_sgpr1_sgpr2_sgpr3
+    ; GCN: [[COPY1:%[0-9]+]]:sreg_32_xm0 = COPY [[COPY]].sub0
+    ; GCN: [[COPY2:%[0-9]+]]:sreg_32_xm0 = COPY [[COPY]].sub1
+    ; GCN: [[COPY3:%[0-9]+]]:sreg_32_xm0 = COPY [[COPY]].sub2
+    ; GCN: [[COPY4:%[0-9]+]]:sreg_32_xm0 = COPY [[COPY]].sub3
+    ; GCN: S_ENDPGM 0, implicit [[COPY1]], implicit [[COPY2]], implicit [[COPY3]], implicit [[COPY4]]
+    %0:sgpr(s128) = COPY $sgpr0_sgpr1_sgpr2_sgpr3
+    %1:sgpr(s32), %2:sgpr(s32), %3:sgpr(s32), %4:sgpr(s32) = G_UNMERGE_VALUES %0
+    S_ENDPGM 0, implicit %1, implicit %2, implicit %3, implicit %4
+...
+
+---
+name: test_unmerge_values_s_s64_s_s64_s_s128
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0_sgpr1_sgpr2_sgpr3
+
+    ; GCN-LABEL: name: test_unmerge_values_s_s64_s_s64_s_s128
+    ; GCN: liveins: $sgpr0_sgpr1_sgpr2_sgpr3
+    ; GCN: [[COPY:%[0-9]+]]:sreg_128 = COPY $sgpr0_sgpr1_sgpr2_sgpr3
+    ; GCN: [[COPY1:%[0-9]+]]:sreg_64_xexec = COPY [[COPY]].sub0_sub1
+    ; GCN: [[COPY2:%[0-9]+]]:sreg_64_xexec = COPY [[COPY]].sub2_sub3
+    ; GCN: S_ENDPGM 0, implicit [[COPY1]], implicit [[COPY2]]
+    %0:sgpr(s128) = COPY $sgpr0_sgpr1_sgpr2_sgpr3
+    %1:sgpr(s64), %2:sgpr(s64) = G_UNMERGE_VALUES %0
+    S_ENDPGM 0, implicit %1, implicit %2
+...
+
+---
+name: test_unmerge_values_rc_set_def_v_s32_v_s32_v_s64
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $vgpr0_vgpr1
+
+    ; GCN-LABEL: name: test_unmerge_values_rc_set_def_v_s32_v_s32_v_s64
+    ; GCN: liveins: $vgpr0_vgpr1
+    ; GCN: [[COPY:%[0-9]+]]:vreg_64 = COPY $vgpr0_vgpr1
+    ; GCN: [[COPY1:%[0-9]+]]:vgpr_32 = COPY [[COPY]].sub0
+    ; GCN: [[COPY2:%[0-9]+]]:vgpr_32 = COPY [[COPY]].sub1
+    ; GCN: S_ENDPGM 0, implicit [[COPY1]], implicit [[COPY2]]
+    %0:vgpr(s64) = COPY $vgpr0_vgpr1
+    %1:vgpr_32(s32), %2:vgpr_32(s32) = G_UNMERGE_VALUES %0
+    S_ENDPGM 0, implicit %1, implicit %2
+...
+
+---
+name: test_unmerge_values_rc_set_use_v_s32_v_s32_v_s64
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $vgpr0_vgpr1
+
+    ; GCN-LABEL: name: test_unmerge_values_rc_set_use_v_s32_v_s32_v_s64
+    ; GCN: liveins: $vgpr0_vgpr1
+    ; GCN: [[COPY:%[0-9]+]]:vreg_64 = COPY $vgpr0_vgpr1
+    ; GCN: [[COPY1:%[0-9]+]]:vgpr_32 = COPY [[COPY]].sub0
+    ; GCN: [[COPY2:%[0-9]+]]:vgpr_32 = COPY [[COPY]].sub1
+    ; GCN: S_ENDPGM 0, implicit [[COPY1]], implicit [[COPY2]]
+    %0:vreg_64(s64) = COPY $vgpr0_vgpr1
+    %1:vgpr(s32), %2:vgpr(s32) = G_UNMERGE_VALUES %0
+    S_ENDPGM 0, implicit %1, implicit %2
+...