diff --git a/clang/lib/Basic/TargetInfo.cpp b/clang/lib/Basic/TargetInfo.cpp
--- a/clang/lib/Basic/TargetInfo.cpp
+++ b/clang/lib/Basic/TargetInfo.cpp
@@ -396,6 +396,19 @@
     HalfFormat = &llvm::APFloat::IEEEhalf();
     FloatFormat = &llvm::APFloat::IEEEsingle();
     LongDoubleFormat = &llvm::APFloat::IEEEquad();
+
+    // OpenCL C v3.0 s6.7.5 - The generic address space requires support for
+    // OpenCL C 2.0 or OpenCL C 3.0 with the __opencl_c_generic_address_space
+    // feature
+    // FIXME: OpenCLGenericAddressSpace is also defined in setLangDefaults()
+    // for OpenCL C 2.0 but with no access to target capabilities. Target
+    // should be immutable once created and thus this language option needs
+    // to be defined only once.
+    if (Opts.OpenCLVersion >= 300) {
+      const auto &OpenCLFeaturesMap = getSupportedOpenCLOpts();
+      Opts.OpenCLGenericAddressSpace = hasFeatureEnabled(
+          OpenCLFeaturesMap, "__opencl_c_generic_address_space");
+    }
   }
 
   if (Opts.DoubleSize) {
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -4072,6 +4072,8 @@
     case tok::kw___generic:
       // generic address space is introduced only in OpenCL v2.0
       // see OpenCL C Spec v2.0 s6.5.5
+      // OpenCL v3.0 introduces __opencl_c_generic_address_space
+      // feature macro to indicate if generic address space is supported
       if (!Actions.getLangOpts().OpenCLGenericAddressSpace) {
         DiagID = diag::err_opencl_unknown_type_specifier;
         PrevSpec = Tok.getIdentifierInfo()->getNameStart();
diff --git a/clang/test/CodeGenOpenCL/address-spaces-conversions.cl b/clang/test/CodeGenOpenCL/address-spaces-conversions.cl
--- a/clang/test/CodeGenOpenCL/address-spaces-conversions.cl
+++ b/clang/test/CodeGenOpenCL/address-spaces-conversions.cl
@@ -1,5 +1,7 @@
 // RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -O0 -ffake-address-space-map -cl-std=CL2.0 -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -O0 -ffake-address-space-map -cl-std=CL3.0 -cl-ext=+__opencl_c_generic_address_space -emit-llvm -o - | FileCheck %s
 // RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -O0 -cl-std=CL2.0 -emit-llvm -o - | FileCheck --check-prefix=CHECK-NOFAKE %s
+// RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -O0 -cl-std=CL3.0 -cl-ext=+__opencl_c_generic_address_space -emit-llvm -o - | FileCheck --check-prefix=CHECK-NOFAKE %s
 // When -ffake-address-space-map is not used, all addr space mapped to 0 for x86_64.
 
 // test that we generate address space casts everywhere we need conversions of
diff --git a/clang/test/CodeGenOpenCL/address-spaces-mangling.cl b/clang/test/CodeGenOpenCL/address-spaces-mangling.cl
--- a/clang/test/CodeGenOpenCL/address-spaces-mangling.cl
+++ b/clang/test/CodeGenOpenCL/address-spaces-mangling.cl
@@ -2,10 +2,14 @@
 // RUN: %clang_cc1 %s -cl-std=CL2.0 -ffake-address-space-map -faddress-space-map-mangling=yes -triple %itanium_abi_triple -emit-llvm -o - | FileCheck -check-prefixes="ASMANG,ASMANG20" %s
 // RUN: %clang_cc1 %s -ffake-address-space-map -faddress-space-map-mangling=no -triple %itanium_abi_triple -emit-llvm -o - | FileCheck -check-prefixes="NOASMANG,NOASMANG10" %s
 // RUN: %clang_cc1 %s -cl-std=CL2.0 -ffake-address-space-map -faddress-space-map-mangling=no -triple %itanium_abi_triple -emit-llvm -o - | FileCheck -check-prefixes="NOASMANG,NOASMANG20" %s
+// RUN: %clang_cc1 %s -cl-std=CL3.0 -cl-std=CL3.0 -cl-ext=+__opencl_c_generic_address_space -ffake-address-space-map -faddress-space-map-mangling=no -triple %itanium_abi_triple -emit-llvm -o - | FileCheck -check-prefixes="NOASMANG,NOASMANG20" %s
+// RUN: %clang_cc1 %s -cl-std=CL3.0 -cl-ext=+__opencl_c_generic_address_space -ffake-address-space-map -faddress-space-map-mangling=yes -triple %itanium_abi_triple -emit-llvm -o - | FileCheck -check-prefixes="ASMANG,ASMANG20" %s
 
 // We check that the address spaces are mangled the same in both version of OpenCL
 // RUN: %clang_cc1 %s -triple spir-unknown-unknown -cl-std=CL2.0 -emit-llvm -o - | FileCheck -check-prefix=OCL-20 %s
 // RUN: %clang_cc1 %s -triple spir-unknown-unknown -cl-std=CL1.2 -emit-llvm -o - | FileCheck -check-prefix=OCL-12 %s
+// RUN: %clang_cc1 %s -triple spir-unknown-unknown -cl-std=CL3.0 -cl-ext=+__opencl_c_generic_address_space -emit-llvm -o - | FileCheck -check-prefix=OCL-20 %s
+// RUN: %clang_cc1 %s -triple spir-unknown-unknown -cl-std=CL3.0 -cl-ext=-__opencl_c_generic_address_space -emit-llvm -o - | FileCheck -check-prefix=OCL-12 %s
 
 // We can't name this f as private is equivalent to default
 // no specifier given address space so we get multiple definition
@@ -47,7 +51,7 @@
 // OCL-20-DAG: @_Z1fPU3AS2i
 // OCL-12-DAG: @_Z1fPU3AS2i
 
-#if __OPENCL_C_VERSION__ >= 200
+#if (__OPENCL_C_VERSION__ == 200) || defined(__opencl_c_generic_address_space)
 __attribute__((overloadable))
 void f(generic int *arg) { }
 // ASMANG20: @_Z1fPU3AS4i
diff --git a/clang/test/CodeGenOpenCL/address-spaces.cl b/clang/test/CodeGenOpenCL/address-spaces.cl
--- a/clang/test/CodeGenOpenCL/address-spaces.cl
+++ b/clang/test/CodeGenOpenCL/address-spaces.cl
@@ -1,9 +1,13 @@
 // RUN: %clang_cc1 %s -O0 -ffake-address-space-map -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK,SPIR
+// RUN: %clang_cc1 %s -O0 -cl-std=CL3.0 -cl-ext=-__opencl_c_generic_address_space -ffake-address-space-map -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK,SPIR
 // RUN: %clang_cc1 %s -O0 -DCL20 -cl-std=CL2.0 -ffake-address-space-map -emit-llvm -o - | FileCheck %s --check-prefixes=CL20,CL20SPIR
 // RUN: %clang_cc1 %s -O0 -triple amdgcn-amd-amdhsa -emit-llvm -o - | FileCheck --check-prefixes=CHECK,AMDGCN %s
+// RUN: %clang_cc1 %s -O0 -triple amdgcn-amd-amdhsa -cl-std=CL3.0 -emit-llvm -o - | FileCheck --check-prefixes=CHECK,AMDGCN %s
 // RUN: %clang_cc1 %s -O0 -triple amdgcn-amd-amdhsa -DCL20 -cl-std=CL2.0 -emit-llvm -o - | FileCheck %s --check-prefixes=CL20,CL20AMDGCN
 // RUN: %clang_cc1 %s -O0 -triple amdgcn-mesa-mesa3d -emit-llvm -o - | FileCheck --check-prefixes=CHECK,AMDGCN %s
+// RUN: %clang_cc1 %s -O0 -triple amdgcn-mesa-mesa3d -cl-std=CL3.0 -emit-llvm -o - | FileCheck --check-prefixes=CHECK,AMDGCN %s
 // RUN: %clang_cc1 %s -O0 -triple r600-- -emit-llvm -o - | FileCheck --check-prefixes=CHECK,AMDGCN %s
+// RUN: %clang_cc1 %s -O0 -triple r600-- -emit-llvm -cl-std=CL3.0 -o - | FileCheck --check-prefixes=CHECK,AMDGCN %s
 
 // SPIR: %struct.S = type { i32, i32, i32* }
 // CL20SPIR: %struct.S = type { i32, i32, i32 addrspace(4)* }
diff --git a/clang/test/CodeGenOpenCL/amdgpu-sizeof-alignof.cl b/clang/test/CodeGenOpenCL/amdgpu-sizeof-alignof.cl
--- a/clang/test/CodeGenOpenCL/amdgpu-sizeof-alignof.cl
+++ b/clang/test/CodeGenOpenCL/amdgpu-sizeof-alignof.cl
@@ -5,6 +5,18 @@
 // RUN: %clang_cc1 -triple amdgcn---amdgizcl -cl-std=CL1.2 %s -emit-llvm -o - | FileCheck %s
 // RUN: %clang_cc1 -triple amdgcn---amdgizcl -cl-std=CL2.0 %s -emit-llvm -o - | FileCheck %s
 
+// RUN: %clang_cc1 -triple r600 -cl-std=CL3.0 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -triple amdgcn-mesa-mesa3d -cl-std=CL3.0 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -triple amdgcn---opencl -cl-std=CL3.0 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -triple amdgcn---amdgizcl -cl-std=CL3.0 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -triple amdgcn-mesa-mesa3d -cl-ext=+__opencl_c_generic_address_space -cl-std=CL3.0 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -triple amdgcn---opencl -cl-ext=+__opencl_c_generic_address_space -cl-std=CL3.0 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -triple amdgcn---amdgizcl -cl-ext=+__opencl_c_generic_address_space -cl-std=CL3.0 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -triple r600 -cl-ext=+cl_khr_fp64,+__opencl_c_fp64 -cl-std=CL3.0 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -triple amdgcn-mesa-mesa3d -cl-ext=+cl_khr_fp64,+__opencl_c_fp64 -cl-std=CL3.0 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -triple amdgcn---opencl -cl-ext=+cl_khr_fp64,+__opencl_c_fp64 -cl-std=CL3.0 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -triple amdgcn---amdgizcl -cl-ext=+cl_khr_fp64,+__opencl_c_fp64 -cl-std=CL3.0 %s -emit-llvm -o - | FileCheck %s
+
 #ifdef __AMDGCN__
 #define PTSIZE 8
 #else
@@ -58,9 +70,12 @@
   check(sizeof(double) == 8);
   check(__alignof__(double) == 8);
 #endif
-
-  check(sizeof(void*) == (__OPENCL_C_VERSION__ >= 200 ? 8 : 4));
-  check(__alignof__(void*) == (__OPENCL_C_VERSION__ >= 200 ? 8 : 4));
+  check(sizeof(private void*) == 4);
+  check(__alignof__(private void*) == 4);
+#if (__OPENCL_C_VERSION__ == 200) || defined(__opencl_c_generic_address_space)
+  check(sizeof(generic void*) == 8);
+  check(__alignof__(generic void*) == 8);
+#endif
   check(sizeof(global_ptr_t) == PTSIZE);
   check(__alignof__(global_ptr_t) == PTSIZE);
   check(sizeof(constant_ptr_t) == PTSIZE);
diff --git a/clang/test/CodeGenOpenCL/overload.cl b/clang/test/CodeGenOpenCL/overload.cl
--- a/clang/test/CodeGenOpenCL/overload.cl
+++ b/clang/test/CodeGenOpenCL/overload.cl
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -cl-std=CL2.0 -emit-llvm -o - -triple spir-unknown-unknown %s | FileCheck %s
+// RUN: %clang_cc1 -cl-std=CL3.0 -cl-ext=+__opencl_c_generic_address_space -emit-llvm -o - -triple spir-unknown-unknown %s | FileCheck %s
 
 typedef short short4 __attribute__((ext_vector_type(4)));
 
diff --git a/clang/test/SemaOpenCL/address-spaces-conversions-cl2.0.cl b/clang/test/SemaOpenCL/address-spaces-conversions-cl2.0.cl
--- a/clang/test/SemaOpenCL/address-spaces-conversions-cl2.0.cl
+++ b/clang/test/SemaOpenCL/address-spaces-conversions-cl2.0.cl
@@ -4,6 +4,9 @@
 // RUN: %clang_cc1 %s -ffake-address-space-map -verify -pedantic -fsyntax-only -DCONSTANT -cl-std=clc++
 // RUN: %clang_cc1 %s -ffake-address-space-map -verify -pedantic -fsyntax-only -DGLOBAL -cl-std=clc++
 // RUN: %clang_cc1 %s -ffake-address-space-map -verify -pedantic -fsyntax-only -DGENERIC -cl-std=clc++
+// RUN: %clang_cc1 %s -ffake-address-space-map -verify -pedantic -fsyntax-only -DCONSTANT -cl-std=CL3.0 -cl-ext=+__opencl_c_generic_address_space
+// RUN: %clang_cc1 %s -ffake-address-space-map -verify -pedantic -fsyntax-only -DGLOBAL -cl-std=CL3.0 -cl-ext=+__opencl_c_generic_address_space
+// RUN: %clang_cc1 %s -ffake-address-space-map -verify -pedantic -fsyntax-only -DGENERIC -cl-std=CL3.0 -cl-ext=+__opencl_c_generic_address_space
 
 /* OpenCLC v2.0 adds a set of restrictions for conversions between pointers to
 *  different address spaces, mainly described in Sections 6.5.5 and 6.5.6.
@@ -17,6 +20,8 @@
 *  case), and __constant, that should cover all program paths for CL address
 *  space conversions used in initialisations, assignments, casts, comparisons
 *  and arithmetic operations.
+*
+*  OpenCLC v3.0 supports generic address if __opencl_c_generic_address_space feature is supported
 */
 
 #ifdef GENERIC
diff --git a/clang/test/SemaOpenCL/address-spaces.cl b/clang/test/SemaOpenCL/address-spaces.cl
--- a/clang/test/SemaOpenCL/address-spaces.cl
+++ b/clang/test/SemaOpenCL/address-spaces.cl
@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only
 // RUN: %clang_cc1 %s -cl-std=CL2.0 -verify -pedantic -fsyntax-only
+// RUN: %clang_cc1 %s -cl-std=CL3.0 -cl-ext=+__opencl_c_generic_address_space -verify -pedantic -fsyntax-only
 // RUN: %clang_cc1 %s -cl-std=clc++ -verify -pedantic -fsyntax-only
 
 __constant int ci = 1;