diff --git a/llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp b/llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp
--- a/llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp
@@ -202,6 +202,18 @@
     LLVM_DEBUG(dbgs() << "  failed: no DPP opcode\n");
     return nullptr;
   }
+  int OrigOpE32 = AMDGPU::getVOPe32(OrigOp);
+  // Prior checks cover Mask with VOPC condition, but not on purpose
+  auto *RowMaskOpnd = TII->getNamedOperand(MovMI, AMDGPU::OpName::row_mask);
+  assert(RowMaskOpnd && RowMaskOpnd->isImm());
+  auto *BankMaskOpnd = TII->getNamedOperand(MovMI, AMDGPU::OpName::bank_mask);
+  assert(BankMaskOpnd && BankMaskOpnd->isImm());
+  const bool MaskAllLanes =
+      RowMaskOpnd->getImm() == 0xF && BankMaskOpnd->getImm() == 0xF;
+  assert(MaskAllLanes ||
+         !(TII->isVOPC(DPPOp) ||
+           (TII->isVOP3(DPPOp) && OrigOpE32 != -1 && TII->isVOPC(OrigOpE32))) &&
+             "VOPC cannot form DPP unless mask is full");
 
   auto DPPInst = BuildMI(*OrigMI.getParent(), OrigMI,
                          OrigMI.getDebugLoc(), TII->get(DPPOp))
@@ -222,7 +234,6 @@
       // If we shrunk a 64bit vop3b to 32bits, just ignore the sdst
     }
 
-    int OrigOpE32 = AMDGPU::getVOPe32(OrigOp);
     const int OldIdx = AMDGPU::getNamedOperandIdx(DPPOp, AMDGPU::OpName::old);
     if (OldIdx != -1) {
       assert(OldIdx == NumOperands);
diff --git a/llvm/test/CodeGen/AMDGPU/vopc_dpp.mir b/llvm/test/CodeGen/AMDGPU/vopc_dpp.mir
--- a/llvm/test/CodeGen/AMDGPU/vopc_dpp.mir
+++ b/llvm/test/CodeGen/AMDGPU/vopc_dpp.mir
@@ -67,3 +67,36 @@
     V_CMP_LT_I32_e32 %0, %18, implicit-def $vcc, implicit $exec
 
 ...
+---
+
+name: mask_not_full
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $vgpr0, $vgpr1, $vgpr2
+
+    ; GCN-LABEL: name: mask_not_full
+    ; GCN: liveins: $vgpr0, $vgpr1, $vgpr2
+    ; GCN-NEXT: {{  $}}
+    ; GCN-NEXT: [[COPY:%[0-9]+]]:vgpr_32 = COPY $vgpr0
+    ; GCN-NEXT: [[COPY1:%[0-9]+]]:vgpr_32 = COPY $vgpr1
+    ; GCN-NEXT: [[DEF:%[0-9]+]]:vgpr_32 = IMPLICIT_DEF
+    ; GCN-NEXT: [[V_MOV_B32_e32_:%[0-9]+]]:vgpr_32 = V_MOV_B32_e32 0, implicit $exec
+    ; GCN-NEXT: [[V_MOV_B32_dpp:%[0-9]+]]:vgpr_32 = V_MOV_B32_dpp [[DEF]], [[COPY1]], 1, 15, 14, 1, implicit $exec
+    ; GCN-NEXT: V_CMP_CLASS_F16_e32 [[V_MOV_B32_dpp]], [[COPY]], implicit-def $vcc, implicit $mode, implicit $exec
+    ; GCN-NEXT: [[V_MOV_B32_dpp1:%[0-9]+]]:vgpr_32 = V_MOV_B32_dpp [[V_MOV_B32_e32_]], [[COPY1]], 1, 13, 15, 1, implicit $exec
+    ; GCN-NEXT: [[V_CMP_GE_F16_e64_:%[0-9]+]]:sgpr_32 = V_CMP_GE_F16_e64 1, [[V_MOV_B32_dpp1]], 0, [[COPY]], 1, implicit $mode, implicit $exec
+    %0:vgpr_32 = COPY $vgpr0
+    %1:vgpr_32 = COPY $vgpr1
+    %2:vgpr_32 = IMPLICIT_DEF
+    %3:vgpr_32 = V_MOV_B32_e32 0, implicit $exec
+
+    ; Do not combine VOPC when row_mask or bank_mask is not 0xf
+    ; All cases are covered by generic rules for creating DPP instructions
+    %4:vgpr_32 = V_MOV_B32_dpp %2, %1, 1, 15, 14, 1, implicit $exec
+    V_CMP_CLASS_F16_e32 %4, %0, implicit-def $vcc, implicit $mode, implicit $exec
+
+    %5:vgpr_32 = V_MOV_B32_dpp %3, %1, 1, 13, 15, 1, implicit $exec
+    %6:sgpr_32 = V_CMP_GE_F16_e64 1, %5, 0, %0, 1, implicit $mode, implicit $exec
+
+...