[SYCL] Fix address space of return values

Emit address space cast if return type and return value have different
address spaces.

Signed-off-by: Mariya Podchishchaeva <[email protected]>

Author: Fznamznon

clang/lib/CodeGen/CGStmt.cpp

@@ -1090,12 +1090,40 @@ void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
     // If this function returns a reference, take the address of the expression
     // rather than the value.
     RValue Result = EmitReferenceBindingToExpr(RV);
-    Builder.CreateStore(Result.getScalarVal(), ReturnValue);
+    llvm::Value *Val = Result.getScalarVal();
+    if (!getenv("DISABLE_INFER_AS")) {
+      if (auto *PtrTy = dyn_cast<llvm::PointerType>(Val->getType())) {
+        auto *ExpectedPtrType =
+            cast<llvm::PointerType>(ReturnValue.getType()->getElementType());
+        unsigned ValueAS = PtrTy->getAddressSpace();
+        unsigned ExpectedAS = ExpectedPtrType->getAddressSpace();
+        if (ValueAS != ExpectedAS) {
+          Val =
+              Builder.CreatePointerBitCastOrAddrSpaceCast(Val, ExpectedPtrType);
+        }
+      }
+    }
+    Builder.CreateStore(Val, ReturnValue);
   } else {
     switch (getEvaluationKind(RV->getType())) {
     case TEK_Scalar:
-      Builder.CreateStore(EmitScalarExpr(RV), ReturnValue);
+    {
+      llvm::Value *Val = EmitScalarExpr(RV);
+      if (!getenv("DISABLE_INFER_AS")) {
+        if (auto *PtrTy = dyn_cast<llvm::PointerType>(Val->getType())) {
+          auto *ExpectedPtrType =
+              cast<llvm::PointerType>(ReturnValue.getType()->getElementType());
+          unsigned ValueAS = PtrTy->getAddressSpace();
+          unsigned ExpectedAS = ExpectedPtrType->getAddressSpace();
+          if (ValueAS != ExpectedAS) {
+            Val = Builder.CreatePointerBitCastOrAddrSpaceCast(
+                Val, ExpectedPtrType);
+          }
+        }
+      }
+      Builder.CreateStore(Val, ReturnValue);
       break;
+    }
     case TEK_Complex:
       EmitComplexExprIntoLValue(RV, MakeAddrLValue(ReturnValue, RV->getType()),
                                 /*isInit*/ true);

clang/test/CodeGenSYCL/address-space-of-returns.cpp

@@ -0,0 +1,43 @@
+// RUN: %clang_cc1 -triple spir64-unknown-linux-sycldevice -std=c++11 -fsycl-is-device -disable-llvm-passes -S -emit-llvm -x c++ %s -o - | FileCheck %s
+
+struct A {
+  int B[42];
+};
+
+const char *ret_char() {
+  return "N";
+}
+// CHECK: ret i8 addrspace(4)* addrspacecast (i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0) to i8 addrspace(4)*)
+
+const char *ret_arr() {
+  static char Arr[42];
+  return Arr;
+}
+// CHECK: ret i8 addrspace(4)* getelementptr inbounds ([42 x i8], [42 x i8] addrspace(4)* addrspacecast ([42 x i8] addrspace(1)* @{{.*}}ret_arr{{.*}}Arr to [42 x i8] addrspace(4)*), i64 0, i64 0)
+
+const char &ret_ref() {
+  static char a = 'A';
+  return a;
+}
+// CHECK: ret i8 addrspace(4)* addrspacecast (i8 addrspace(1)* @{{.*}}ret_ref{{.*}} to i8 addrspace(4)*)
+
+A ret_agg() {
+  A a;
+  return a;
+}
+// CHECK: define spir_func void @{{.*}}ret_agg{{.*}}(%struct.{{.*}}.A addrspace(4)* noalias sret %agg.result)
+
+template <typename name, typename Func>
+__attribute__((sycl_kernel)) void kernel_single_task(Func kernelFunc) {
+  kernelFunc();
+}
+
+int main() {
+  kernel_single_task<class kernel>([]() {
+    ret_char();
+    ret_arr();
+    ret_ref();
+    ret_agg();
+  });
+  return 0;
+}