diff --git a/lib/SPIRV/SPIRVReader.cpp b/lib/SPIRV/SPIRVReader.cpp
index 4d7c3eb23..66793e25d 100644
--- a/lib/SPIRV/SPIRVReader.cpp
+++ b/lib/SPIRV/SPIRVReader.cpp
@@ -1607,6 +1607,15 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
   case OpUndef:
     return mapValue(BV, UndefValue::get(transType(BV->getType())));
 
+  case OpSizeOf: {
+    Type *ResTy = transType(BV->getType());
+    auto *BI = static_cast<SPIRVSizeOf *>(BV);
+    SPIRVType *TypeArg = reinterpret_cast<SPIRVType *>(BI->getOpValue(0));
+    Type *EltTy = transType(TypeArg->getPointerElementType());
+    uint64_t Size = M->getDataLayout().getTypeStoreSize(EltTy).getFixedValue();
+    return mapValue(BV, ConstantInt::get(ResTy, Size));
+  }
+
   case OpVariable: {
     auto BVar = static_cast<SPIRVVariable *>(BV);
     auto *PreTransTy = BVar->getType()->getPointerElementType();
diff --git a/lib/SPIRV/libSPIRV/SPIRVEntry.h b/lib/SPIRV/libSPIRV/SPIRVEntry.h
index 5f360ede4..7b10d181b 100644
--- a/lib/SPIRV/libSPIRV/SPIRVEntry.h
+++ b/lib/SPIRV/libSPIRV/SPIRVEntry.h
@@ -1086,7 +1086,6 @@ _SPIRV_OP(NamedBarrierInitialize)
 _SPIRV_OP(MemoryNamedBarrier)
 _SPIRV_OP(GetKernelMaxNumSubgroups)
 _SPIRV_OP(GetKernelLocalSizeForSubgroupCount)
-_SPIRV_OP(SizeOf)
 #undef _SPIRV_OP
 
 } // namespace SPIRV
diff --git a/lib/SPIRV/libSPIRV/SPIRVInstruction.h b/lib/SPIRV/libSPIRV/SPIRVInstruction.h
index b9968ef77..7ab9358af 100644
--- a/lib/SPIRV/libSPIRV/SPIRVInstruction.h
+++ b/lib/SPIRV/libSPIRV/SPIRVInstruction.h
@@ -1540,6 +1540,16 @@ class SPIRVTranspose : public SPIRVInstruction {
   SPIRVId Matrix;
 };
 
+class SPIRVSizeOfInstBase : public SPIRVInstTemplateBase {
+protected:
+  SPIRVWord getRequiredSPIRVVersion() const override {
+    return static_cast<SPIRVWord>(VersionNumber::SPIRV_1_1);
+  }
+};
+
+typedef SPIRVInstTemplate<SPIRVSizeOfInstBase, OpSizeOf, true, 4, false>
+    SPIRVSizeOf;
+
 class SPIRVUnary : public SPIRVInstTemplateBase {
 protected:
   void validate() const override {
diff --git a/lib/SPIRV/libSPIRV/SPIRVOpCodeEnum.h b/lib/SPIRV/libSPIRV/SPIRVOpCodeEnum.h
index a31342dc3..aa21bf4ed 100644
--- a/lib/SPIRV/libSPIRV/SPIRVOpCodeEnum.h
+++ b/lib/SPIRV/libSPIRV/SPIRVOpCodeEnum.h
@@ -291,6 +291,7 @@ _SPIRV_OP(ImageSparseTexelsResident, 316)
 _SPIRV_OP(NoLine, 317)
 _SPIRV_OP(AtomicFlagTestAndSet, 318)
 _SPIRV_OP(AtomicFlagClear, 319)
+_SPIRV_OP(SizeOf, 321)
 _SPIRV_OP(TypePipeStorage, 322)
 _SPIRV_OP(ConstantPipeStorage, 323)
 _SPIRV_OP(CreatePipeFromPipeStorage, 324)
diff --git a/test/OpSizeOf.spvasm b/test/OpSizeOf.spvasm
new file mode 100644
index 000000000..0006afae7
--- /dev/null
+++ b/test/OpSizeOf.spvasm
@@ -0,0 +1,33 @@
+; REQUIRES: spirv-as
+; RUN: spirv-as --target-env spv1.1 -o %t.spv %s
+; TODO: reenable spirv-val when OpSizeOf is supported.
+; R/U/N: spirv-val %t.spv
+; RUN: llvm-spirv -r -o - %t.spv | llvm-dis | FileCheck %s
+               OpCapability Addresses
+               OpCapability Kernel
+               OpMemoryModel Physical64 OpenCL
+               OpEntryPoint Kernel %f "testSizeOf"
+               OpName %p "p"
+       %void = OpTypeVoid
+       %bool = OpTypeBool
+        %i32 = OpTypeInt 32 0
+     %struct = OpTypeStruct %i32 %i32
+%_ptr_CrossWorkgroup_bool = OpTypePointer CrossWorkgroup %bool
+%_ptr_CrossWorkgroup_i32 = OpTypePointer CrossWorkgroup %i32
+%_ptr_CrossWorkgroup_struct = OpTypePointer CrossWorkgroup %struct
+       %fnTy = OpTypeFunction %void %_ptr_CrossWorkgroup_i32
+
+          %f = OpFunction %void None %fnTy
+          %p = OpFunctionParameter %_ptr_CrossWorkgroup_i32
+         %10 = OpLabel
+
+; CHECK: store i32 1, ptr addrspace(1) %p
+         %11 = OpSizeOf %i32 %_ptr_CrossWorkgroup_bool
+               OpStore %p %11
+
+; CHECK: store i32 8, ptr addrspace(1) %p
+         %12 = OpSizeOf %i32 %_ptr_CrossWorkgroup_struct
+               OpStore %p %12
+
+               OpReturn
+               OpFunctionEnd