Index: clang/lib/Basic/Targets/SPIR.h
===================================================================
--- clang/lib/Basic/Targets/SPIR.h
+++ clang/lib/Basic/Targets/SPIR.h
@@ -104,6 +104,8 @@
   }
 
   bool hasExtIntType() const override { return true; }
+
+  bool hasInt128Type() const override { return false; }
 };
 class LLVM_LIBRARY_VISIBILITY SPIR32TargetInfo : public SPIRTargetInfo {
 public:
Index: clang/lib/Sema/Sema.cpp
===================================================================
--- clang/lib/Sema/Sema.cpp
+++ clang/lib/Sema/Sema.cpp
@@ -236,7 +236,9 @@
     return;
 
   // Initialize predefined 128-bit integer types, if needed.
-  if (Context.getTargetInfo().hasInt128Type()) {
+  if (Context.getTargetInfo().hasInt128Type() ||
+      (Context.getAuxTargetInfo() &&
+       Context.getAuxTargetInfo()->hasInt128Type())) {
     // If either of the 128-bit integer types are unavailable to name lookup,
     // define them now.
     DeclarationName Int128 = &Context.Idents.get("__int128_t");
Index: clang/lib/Sema/SemaOverload.cpp
===================================================================
--- clang/lib/Sema/SemaOverload.cpp
+++ clang/lib/Sema/SemaOverload.cpp
@@ -8199,12 +8199,16 @@
     ArithmeticTypes.push_back(S.Context.IntTy);
     ArithmeticTypes.push_back(S.Context.LongTy);
     ArithmeticTypes.push_back(S.Context.LongLongTy);
-    if (S.Context.getTargetInfo().hasInt128Type())
+    if (S.Context.getTargetInfo().hasInt128Type() ||
+        (S.Context.getAuxTargetInfo() &&
+         S.Context.getAuxTargetInfo()->hasInt128Type()))
       ArithmeticTypes.push_back(S.Context.Int128Ty);
     ArithmeticTypes.push_back(S.Context.UnsignedIntTy);
     ArithmeticTypes.push_back(S.Context.UnsignedLongTy);
     ArithmeticTypes.push_back(S.Context.UnsignedLongLongTy);
-    if (S.Context.getTargetInfo().hasInt128Type())
+    if (S.Context.getTargetInfo().hasInt128Type() ||
+        (S.Context.getAuxTargetInfo() &&
+         S.Context.getAuxTargetInfo()->hasInt128Type()))
       ArithmeticTypes.push_back(S.Context.UnsignedInt128Ty);
     LastPromotedIntegralType = ArithmeticTypes.size();
     LastPromotedArithmeticType = ArithmeticTypes.size();
Index: clang/lib/Sema/SemaType.cpp
===================================================================
--- clang/lib/Sema/SemaType.cpp
+++ clang/lib/Sema/SemaType.cpp
@@ -1515,6 +1515,7 @@
   }
   case DeclSpec::TST_int128:
     if (!S.Context.getTargetInfo().hasInt128Type() &&
+        !S.getLangOpts().SYCLIsDevice &&
         !(S.getLangOpts().OpenMP && S.getLangOpts().OpenMPIsDevice))
       S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_unsupported)
         << "__int128";
Index: clang/test/CodeGen/ext-int-cc.c
===================================================================
--- clang/test/CodeGen/ext-int-cc.c
+++ clang/test/CodeGen/ext-int-cc.c
@@ -43,7 +43,7 @@
 // SPARC: define void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
 // MIPS64: define void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128 signext  %{{.+}}, i64 signext %{{.+}})
 // MIPS: define void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 signext %{{.+}})
-// SPIR64: define spir_func void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128 %{{.+}}, i64 %{{.+}})
+// SPIR64: define spir_func void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
 // SPIR: define spir_func void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
 // HEX: define void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
 // LANAI: define void @ParamPassing(i129* byval(i129) align 4 %{{.+}}, i128* byval(i128) align 4 %{{.+}}, i64 %{{.+}})
@@ -72,7 +72,7 @@
 // SPARC: define void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
 // MIPS64: define void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127 signext  %{{.+}}, i63 signext %{{.+}})
 // MIPS: define void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 signext %{{.+}})
-// SPIR64: define spir_func void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127 %{{.+}}, i63 %{{.+}})
+// SPIR64: define spir_func void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
 // SPIR: define spir_func void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
 // HEX: define void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
 // LANAI: define void @ParamPassing2(i129* byval(i129) align 4 %{{.+}}, i127* byval(i127) align 4 %{{.+}}, i63 %{{.+}})
@@ -191,7 +191,7 @@
 // SPARC: define void @ReturnPassing3(i127* noalias sret
 // MIPS64: define i127 @ReturnPassing3(
 // MIPS: define void @ReturnPassing3(i127* noalias sret
-// SPIR64: define spir_func i127 @ReturnPassing3(
+// SPIR64: define spir_func void @ReturnPassing3(i127* noalias sret
 // SPIR: define spir_func void @ReturnPassing3(i127* noalias sret
 // HEX: define void @ReturnPassing3(i127* noalias sret
 // LANAI: define void @ReturnPassing3(i127* noalias sret
@@ -220,7 +220,7 @@
 // SPARC: define void @ReturnPassing4(i128* noalias sret
 // MIPS64: define i128 @ReturnPassing4(
 // MIPS: define void @ReturnPassing4(i128* noalias sret
-// SPIR64: define spir_func i128 @ReturnPassing4(
+// SPIR64: define spir_func void @ReturnPassing4(i128* noalias sret
 // SPIR: define spir_func void @ReturnPassing4(i128* noalias sret
 // HEX: define void @ReturnPassing4(i128* noalias sret
 // LANAI: define void @ReturnPassing4(i128* noalias sret
Index: clang/test/SemaSYCL/int128.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaSYCL/int128.cpp
@@ -0,0 +1,118 @@
+// RUN: %clang_cc1 -triple spir64 -aux-triple x86_64-unknown-linux-gnu \
+// RUN:    -fsycl -fsycl-is-device -verify -fsyntax-only %s
+
+typedef __uint128_t BIGTY;
+
+template <class T>
+class Z {
+public:
+  // expected-note@+1 {{'field' defined here}}
+  T field;
+  // expected-note@+1 2{{'field1' defined here}}
+  __int128 field1;
+  using BIGTYPE = __int128;
+  // expected-note@+1 {{'bigfield' defined here}}
+  BIGTYPE bigfield;
+};
+
+void host_ok(void) {
+  __int128 A;
+  int B = sizeof(__int128);
+  Z<__int128> C;
+  C.field1 = A;
+}
+
+void usage() {
+  // expected-note@+1 3{{'A' defined here}}
+  __int128 A;
+  Z<__int128> C;
+  // expected-error@+2 {{'A' requires 128 bit size '__int128' type support, but device 'spir64' does not support it}}
+  // expected-error@+1 {{'field1' requires 128 bit size '__int128' type support, but device 'spir64' does not support it}}
+  C.field1 = A;
+  // expected-error@+1 {{'bigfield' requires 128 bit size 'Z::BIGTYPE' (aka '__int128') type support, but device 'spir64' does not support it}}
+  C.bigfield += 1.0;
+
+  // expected-error@+1 {{'A' requires 128 bit size '__int128' type support, but device 'spir64' does not support it}}
+  auto foo1 = [=]() {
+    __int128 AA;
+    // expected-note@+2 {{'BB' defined here}}
+    // expected-error@+1 {{'A' requires 128 bit size '__int128' type support, but device 'spir64' does not support it}}
+    auto BB = A;
+    // expected-error@+1 {{'BB' requires 128 bit size '__int128' type support, but device 'spir64' does not support it}}
+    BB += 1;
+  };
+
+  // expected-note@+1 {{called by 'usage'}}
+  foo1();
+}
+
+template <typename t>
+void foo2(){};
+
+// expected-note@+3 {{'P' defined here}}
+// expected-error@+2 {{'P' requires 128 bit size '__int128' type support, but device 'spir64' does not support it}}
+// expected-note@+1 2{{'foo' defined here}}
+__int128 foo(__int128 P) { return P; }
+
+void foobar() {
+  // expected-note@+1 {{'operator __int128' defined here}}
+  struct X { operator  __int128() const; } x;
+  bool a = false;
+  // expected-error@+1 {{'operator __int128' requires 128 bit size '__int128' type support, but device 'spir64' does not support it}}
+  a = x == __int128(0);
+}
+
+template <typename Name, typename Func>
+__attribute__((sycl_kernel)) void kernel(Func kernelFunc) {
+  // expected-note@+1 6{{called by 'kernel}}
+  kernelFunc();
+}
+
+int main() {
+  // expected-note@+1 {{'CapturedToDevice' defined here}}
+  __int128 CapturedToDevice = 1;
+  host_ok();
+  kernel<class variables>([=]() {
+    decltype(CapturedToDevice) D;
+    // expected-error@+1 {{'CapturedToDevice' requires 128 bit size '__int128' type support, but device 'spir64' does not support it}}
+    auto C = CapturedToDevice;
+    Z<__int128> S;
+    // expected-error@+1 {{'field1' requires 128 bit size '__int128' type support, but device 'spir64' does not support it}}
+    S.field1 += 1;
+    // expected-error@+1 {{'field' requires 128 bit size '__int128' type support, but device 'spir64' does not support it}}
+    S.field = 1;
+  });
+
+  kernel<class functions>([=]() {
+    // expected-note@+1 2{{called by 'operator()'}}
+    usage();
+    // expected-note@+1 {{'BBBB' defined here}}
+    BIGTY BBBB;
+    // expected-error@+3 {{'BBBB' requires 128 bit size 'BIGTY' (aka 'unsigned __int128') type support, but device 'spir64' does not support it}}
+    // expected-error@+2 2{{'foo' requires 128 bit size '__int128' type support, but device 'spir64' does not support it}}
+    // expected-note@+1 1{{called by 'operator()'}}
+    auto A = foo(BBBB);
+    // expected-note@+1 {{called by 'operator()'}}
+    foobar();
+  });
+
+  kernel<class ok>([=]() {
+    Z<__int128> S;
+    foo2<__int128>();
+    auto A = sizeof(CapturedToDevice);
+  });
+
+  return 0;
+}
+
+// no error expected
+BIGTY zoo(BIGTY h) {
+  h = 1;
+  return h;
+}
+
+namespace PR12964 {
+  struct X { operator  __int128() const; } x;
+  bool a = x == __int128(0);
+}
+