diff --git a/src/dxbc/dxbc_compiler.cpp b/src/dxbc/dxbc_compiler.cpp
index c4d092f5a..0cdb391ec 100644
--- a/src/dxbc/dxbc_compiler.cpp
+++ b/src/dxbc/dxbc_compiler.cpp
@@ -2436,11 +2436,16 @@ namespace dxvk {
     //    (src2) The sampler, with a component selector
     // Gather4C takes the following additional operand:
     //    (src3) The depth reference value
+    // The Gather4Po variants take an additional operand
+    // which defines an extended constant offset.
     // TODO reduce code duplication by moving some common code
     // in both sample() and gather() into separate methods
+    const bool isExtendedGather = ins.op == DxbcOpcode::Gather4Po
+                               || ins.op == DxbcOpcode::Gather4PoC;
+    
     const DxbcRegister& texCoordReg = ins.src[0];
-    const DxbcRegister& textureReg  = ins.src[1];
-    const DxbcRegister& samplerReg  = ins.src[2];
+    const DxbcRegister& textureReg  = ins.src[1 + isExtendedGather];
+    const DxbcRegister& samplerReg  = ins.src[2 + isExtendedGather];
     
     // Texture and sampler register IDs
     const uint32_t textureId = textureReg.idx[0].offset;
@@ -2459,10 +2464,12 @@ namespace dxvk {
     DxbcRegisterValue coord = emitRegisterLoad(texCoordReg, coordArrayMask);
     
     // Load reference value for depth-compare operations
-    const bool isDepthCompare = ins.op == DxbcOpcode::Gather4C;
+    const bool isDepthCompare = ins.op == DxbcOpcode::Gather4C
+                             || ins.op == DxbcOpcode::Gather4PoC;
     
     const DxbcRegisterValue referenceValue = isDepthCompare
-      ? emitRegisterLoad(ins.src[3], DxbcRegMask(true, false, false, false))
+      ? emitRegisterLoad(ins.src[3 + isExtendedGather],
+          DxbcRegMask(true, false, false, false))
       : DxbcRegisterValue();
     
     if (isDepthCompare && m_options.packDrefValueIntoCoordinates) {
@@ -2484,7 +2491,15 @@ namespace dxvk {
     // Accumulate additional image operands.
     SpirvImageOperands imageOperands;
     
-    if (ins.sampleControls.u != 0 || ins.sampleControls.v != 0 || ins.sampleControls.w != 0) {
+    if (isExtendedGather) {
+      m_module.enableCapability(spv::CapabilityImageGatherExtended);
+      
+      DxbcRegisterValue gatherOffset = emitRegisterLoad(
+        ins.src[1], DxbcRegMask::firstN(imageLayerDim));
+      
+      imageOperands.flags |= spv::ImageOperandsOffsetMask;
+      imageOperands.gOffset = gatherOffset.id;
+    } else if (ins.sampleControls.u != 0 || ins.sampleControls.v != 0 || ins.sampleControls.w != 0) {
       const std::array<uint32_t, 3> offsetIds = {
         imageLayerDim >= 1 ? m_module.consti32(ins.sampleControls.u) : 0,
         imageLayerDim >= 2 ? m_module.consti32(ins.sampleControls.v) : 0,
diff --git a/src/dxbc/dxbc_defs.cpp b/src/dxbc/dxbc_defs.cpp
index 8be6e7a81..876a93984 100644
--- a/src/dxbc/dxbc_defs.cpp
+++ b/src/dxbc/dxbc_defs.cpp
@@ -600,9 +600,22 @@ namespace dxvk {
       { DxbcOperandKind::SrcReg, DxbcScalarType::Float32 },
     } },
     /* Gather4Po                            */
-    { },
+    { 5, DxbcInstClass::TextureGather, {
+      { DxbcOperandKind::DstReg, DxbcScalarType::Float32 },
+      { DxbcOperandKind::SrcReg, DxbcScalarType::Float32 },
+      { DxbcOperandKind::SrcReg, DxbcScalarType::Sint32  },
+      { DxbcOperandKind::SrcReg, DxbcScalarType::Float32 },
+      { DxbcOperandKind::SrcReg, DxbcScalarType::Float32 },
+    } },
     /* Gather4PoC                           */
-    { },
+    { 6, DxbcInstClass::TextureGather, {
+      { DxbcOperandKind::DstReg, DxbcScalarType::Float32 },
+      { DxbcOperandKind::SrcReg, DxbcScalarType::Float32 },
+      { DxbcOperandKind::SrcReg, DxbcScalarType::Sint32  },
+      { DxbcOperandKind::SrcReg, DxbcScalarType::Float32 },
+      { DxbcOperandKind::SrcReg, DxbcScalarType::Float32 },
+      { DxbcOperandKind::SrcReg, DxbcScalarType::Float32 },
+    } },
     /* Rcp                                  */
     { 2, DxbcInstClass::VectorAlu, {
       { DxbcOperandKind::DstReg, DxbcScalarType::Float32 },
diff --git a/src/spirv/spirv_module.cpp b/src/spirv/spirv_module.cpp
index fa1cea670..7875a22e2 100644
--- a/src/spirv/spirv_module.cpp
+++ b/src/spirv/spirv_module.cpp
@@ -933,6 +933,64 @@ namespace dxvk {
   }
   
   
+  uint32_t SpirvModule::opBitCount(
+          uint32_t                resultType,
+          uint32_t                operand) {
+    uint32_t resultId = this->allocateId();
+    
+    m_code.putIns (spv::OpBitCount, 4);
+    m_code.putWord(resultType);
+    m_code.putWord(resultId);
+    m_code.putWord(operand);
+    return resultId;
+  }
+  
+  
+  uint32_t SpirvModule::opFindILsb(
+          uint32_t                resultType,
+          uint32_t                operand) {
+    uint32_t resultId = this->allocateId();
+    
+    m_code.putIns (spv::OpExtInst, 6);
+    m_code.putWord(resultType);
+    m_code.putWord(resultId);
+    m_code.putWord(m_instExtGlsl450);
+    m_code.putWord(spv::GLSLstd450FindILsb);
+    m_code.putWord(operand);
+    return resultId;
+  }
+  
+  
+  uint32_t SpirvModule::opFindUMsb(
+          uint32_t                resultType,
+          uint32_t                operand) {
+    uint32_t resultId = this->allocateId();
+    
+    m_code.putIns (spv::OpExtInst, 6);
+    m_code.putWord(resultType);
+    m_code.putWord(resultId);
+    m_code.putWord(m_instExtGlsl450);
+    m_code.putWord(spv::GLSLstd450FindUMsb);
+    m_code.putWord(operand);
+    return resultId;
+  }
+  
+  
+  uint32_t SpirvModule::opFindSMsb(
+          uint32_t                resultType,
+          uint32_t                operand) {
+    uint32_t resultId = this->allocateId();
+    
+    m_code.putIns (spv::OpExtInst, 6);
+    m_code.putWord(resultType);
+    m_code.putWord(resultId);
+    m_code.putWord(m_instExtGlsl450);
+    m_code.putWord(spv::GLSLstd450FindSMsb);
+    m_code.putWord(operand);
+    return resultId;
+  }
+  
+            
   uint32_t SpirvModule::opBitFieldInsert(
           uint32_t                resultType,
           uint32_t                base,
diff --git a/src/spirv/spirv_module.h b/src/spirv/spirv_module.h
index 18b262106..60f735626 100644
--- a/src/spirv/spirv_module.h
+++ b/src/spirv/spirv_module.h
@@ -377,6 +377,22 @@ namespace dxvk {
             uint32_t                resultType,
             uint32_t                operand);
             
+    uint32_t opBitCount(
+            uint32_t                resultType,
+            uint32_t                operand);
+    
+    uint32_t opFindILsb(
+            uint32_t                resultType,
+            uint32_t                operand);
+    
+    uint32_t opFindUMsb(
+            uint32_t                resultType,
+            uint32_t                operand);
+    
+    uint32_t opFindSMsb(
+            uint32_t                resultType,
+            uint32_t                operand);
+    
     uint32_t opBitFieldInsert(
             uint32_t                resultType,
             uint32_t                base,