Index: lib/Target/AMDGPU/SIInstrInfo.h
===================================================================
--- lib/Target/AMDGPU/SIInstrInfo.h
+++ lib/Target/AMDGPU/SIInstrInfo.h
@@ -78,6 +78,9 @@
   void lowerScalarAbs(SetVectorType &Worklist,
                       MachineInstr &Inst) const;
 
+  void lowerScalarXnor(SetVectorType &Worklist,
+                       MachineInstr &Inst) const;
+
   void splitScalar64BitUnaryOp(SetVectorType &Worklist,
                                MachineInstr &Inst, unsigned Opcode) const;
 
Index: lib/Target/AMDGPU/SIInstrInfo.cpp
===================================================================
--- lib/Target/AMDGPU/SIInstrInfo.cpp
+++ lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -3686,6 +3686,16 @@
       movePackToVALU(Worklist, MRI, Inst);
       Inst.eraseFromParent();
       continue;
+
+    case AMDGPU::S_XNOR_B32:
+      lowerScalarXnor(Worklist, Inst);
+      Inst.eraseFromParent();
+      continue;
+
+    case AMDGPU::S_XNOR_B64:
+      splitScalar64BitBinaryOp(Worklist, Inst, AMDGPU::S_XNOR_B32);
+      Inst.eraseFromParent();
+      continue;
     }
 
     if (NewOpcode == AMDGPU::INSTRUCTION_LIST_END) {
@@ -3804,6 +3814,33 @@
   addUsersToMoveToVALUWorklist(ResultReg, MRI, Worklist);
 }
 
+void SIInstrInfo::lowerScalarXnor(SetVectorType &Worklist,
+                                  MachineInstr &Inst) const {
+  MachineBasicBlock &MBB = *Inst.getParent();
+  MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
+  MachineBasicBlock::iterator MII = Inst;
+  DebugLoc DL = Inst.getDebugLoc();
+
+  MachineOperand &Dest = Inst.getOperand(0);
+  MachineOperand &Src0 = Inst.getOperand(1);
+  MachineOperand &Src1 = Inst.getOperand(2);
+
+  legalizeGenericOperand(MBB, MII, &AMDGPU::VGPR_32RegClass, Src0, MRI, DL);
+  legalizeGenericOperand(MBB, MII, &AMDGPU::VGPR_32RegClass, Src1, MRI, DL);
+
+  unsigned Xor = MRI.createVirtualRegister(&AMDGPU::VGPR_32RegClass);
+  BuildMI(MBB, MII, DL, get(AMDGPU::V_XOR_B32_e64), Xor)
+    .add(Src0)
+    .add(Src1);
+
+  unsigned Not = MRI.createVirtualRegister(&AMDGPU::VGPR_32RegClass);
+  BuildMI(MBB, MII, DL, get(AMDGPU::V_NOT_B32_e64), Not)
+    .addReg(Xor);
+
+  MRI.replaceRegWith(Dest.getReg(), Not);
+  addUsersToMoveToVALUWorklist(Not, MRI, Worklist);
+}
+
 void SIInstrInfo::splitScalar64BitUnaryOp(
     SetVectorType &Worklist, MachineInstr &Inst,
     unsigned Opcode) const {
Index: lib/Target/AMDGPU/SOPInstructions.td
===================================================================
--- lib/Target/AMDGPU/SOPInstructions.td
+++ lib/Target/AMDGPU/SOPInstructions.td
@@ -391,6 +391,14 @@
 def S_XOR_B64 : SOP2_64 <"s_xor_b64",
   [(set i64:$sdst, (xor i64:$src0, i64:$src1))]
 >;
+
+def S_XNOR_B32 : SOP2_32 <"s_xnor_b32",
+  [(set i32:$sdst, (xor (xor_oneuse i32:$src0, i32:$src1), (i32 -1)))]
+>;
+
+def S_XNOR_B64 : SOP2_64 <"s_xnor_b64",
+  [(set i64:$sdst, (xor (xor_oneuse i64:$src0, i64:$src1), (i64 -1)))]
+>;
 } // End isCommutable = 1
 
 def S_ANDN2_B32 : SOP2_32 <"s_andn2_b32">;
@@ -401,8 +409,6 @@
 def S_NAND_B64 : SOP2_64 <"s_nand_b64">;
 def S_NOR_B32 : SOP2_32 <"s_nor_b32">;
 def S_NOR_B64 : SOP2_64 <"s_nor_b64">;
-def S_XNOR_B32 : SOP2_32 <"s_xnor_b32">;
-def S_XNOR_B64 : SOP2_64 <"s_xnor_b64">;
 } // End Defs = [SCC]
 
 // Use added complexity so these patterns are preferred to the VALU patterns.
Index: test/CodeGen/AMDGPU/xnor.ll
===================================================================
--- /dev/null
+++ test/CodeGen/AMDGPU/xnor.ll
@@ -0,0 +1,76 @@
+; RUN: llc -march=amdgcn -mcpu=gfx600 -verify-machineinstrs < %s | FileCheck --check-prefix=GCN --check-prefix=GFX600 %s
+; RUN: llc -march=amdgcn -mcpu=gfx700 -verify-machineinstrs < %s | FileCheck --check-prefix=GCN --check-prefix=GFX700 %s
+; RUN: llc -march=amdgcn -mcpu=gfx800 -verify-machineinstrs < %s | FileCheck --check-prefix=GCN --check-prefix=GFX800 %s
+; RUN: llc -march=amdgcn -mcpu=gfx900 -verify-machineinstrs < %s | FileCheck --check-prefix=GCN --check-prefix=GFX900 %s
+
+; GCN-LABEL: {{^}}scalar_xnor_i32_one_use
+; GCN: s_xnor_b32
+define amdgpu_kernel void @scalar_xnor_i32_one_use(
+    i32 addrspace(1)* %r0, i32 %a, i32 %b) {
+entry:
+  %xor = xor i32 %a, %b
+  %r0.val = xor i32 %xor, -1
+  store i32 %r0.val, i32 addrspace(1)* %r0
+  ret void
+}
+
+; GCN-LABEL: {{^}}scalar_xnor_i32_mul_use
+; GCN-NOT: s_xnor_b32
+define amdgpu_kernel void @scalar_xnor_i32_mul_use(
+    i32 addrspace(1)* %r0, i32 addrspace(1)* %r1, i32 %a, i32 %b) {
+entry:
+  %xor = xor i32 %a, %b
+  %r0.val = xor i32 %xor, -1
+  %r1.val = add i32 %xor, %a
+  store i32 %r0.val, i32 addrspace(1)* %r0
+  store i32 %r1.val, i32 addrspace(1)* %r1
+  ret void
+}
+
+; GCN-LABEL: {{^}}scalar_xnor_i64_one_use
+; GCN: s_xnor_b64
+define amdgpu_kernel void @scalar_xnor_i64_one_use(
+    i64 addrspace(1)* %r0, i64 %a, i64 %b) {
+entry:
+  %xor = xor i64 %a, %b
+  %r0.val = xor i64 %xor, -1
+  store i64 %r0.val, i64 addrspace(1)* %r0
+  ret void
+}
+
+; GCN-LABEL: {{^}}scalar_xnor_i64_mul_use
+; GCN-NOT: s_xnor_b64
+define amdgpu_kernel void @scalar_xnor_i64_mul_use(
+    i64 addrspace(1)* %r0, i64 addrspace(1)* %r1, i64 %a, i64 %b) {
+entry:
+  %xor = xor i64 %a, %b
+  %r0.val = xor i64 %xor, -1
+  %r1.val = add i64 %xor, %a
+  store i64 %r0.val, i64 addrspace(1)* %r0
+  store i64 %r1.val, i64 addrspace(1)* %r1
+  ret void
+}
+
+; GCN-LABEL: {{^}}vector_xnor_i32_one_use
+; GCN-NOT: s_xnor_b32
+; GCN: v_xor_b32
+; GCN: v_not_b32
+define i32 @vector_xnor_i32_one_use(i32 %a, i32 %b) {
+entry:
+  %xor = xor i32 %a, %b
+  %r = xor i32 %xor, -1
+  ret i32 %r
+}
+
+; GCN-LABEL: {{^}}vector_xnor_i64_one_use
+; GCN-NOT: s_xnor_b64
+; GCN: v_xor_b32
+; GCN: v_xor_b32
+; GCN: v_not_b32
+; GCN: v_not_b32
+define i64 @vector_xnor_i64_one_use(i64 %a, i64 %b) {
+entry:
+  %xor = xor i64 %a, %b
+  %r = xor i64 %xor, -1
+  ret i64 %r
+}