[SYCL] Fix addressspace cast for _alloca (intel#6087)

This is a follow-up to PR#6050. The cast should use
element type and not change type. PR#6050 incorrectly
change Type* to Type** (when adding the cast)

This patch also add opaque pointer version of the test.

Signed-off-by: Elizabeth Andrews <elizabeth.andrews@intel.com>

clang/lib/CodeGen/CGExprScalar.cpp

@@ -2058,10 +2058,17 @@ Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
     Value *Src = Visit(const_cast<Expr*>(E));
     llvm::Type *SrcTy = Src->getType();
     llvm::Type *DstTy = ConvertType(DestTy);
-    if (SrcTy->isPtrOrPtrVectorTy() && DstTy->isPtrOrPtrVectorTy() &&
+
+    if (SrcTy->isPointerTy() && DstTy->isPointerTy() &&
         SrcTy->getPointerAddressSpace() != DstTy->getPointerAddressSpace())
       Src = Builder.CreateAddrSpaceCast(
-          Src, llvm::PointerType::get(SrcTy, DstTy->getPointerAddressSpace()));
+          Src,
+          llvm::PointerType::getWithSamePointeeType(
+              cast<llvm::PointerType>(SrcTy), DstTy->getPointerAddressSpace()));
+    else if (SrcTy->isPtrOrPtrVectorTy() && DstTy->isPtrOrPtrVectorTy() &&
+             SrcTy->getPointerAddressSpace() != DstTy->getPointerAddressSpace())
+      llvm_unreachable("wrong cast for pointers in different address spaces"
+                       "(must be an address space cast)!");
 
     if (CGF.SanOpts.has(SanitizerKind::CFIUnrelatedCast)) {
       if (auto *PT = DestTy->getAs<PointerType>()) {

clang/test/CodeGenSYCL/address-space-builtin-alloca.cpp

@@ -1,13 +1,12 @@
-// RUN: %clang_cc1 -triple spir64-unknown-linux -fsycl-is-device -disable-llvm-passes -emit-llvm -x c++ %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple spir64-unknown-linux -fsycl-is-device -disable-llvm-passes -opaque-pointers -emit-llvm -x c++ %s -o - | FileCheck %s
 
 // Test to verify that address space cast is generated correctly for __builtin_alloca
 
 __attribute__((sycl_device)) void foo() {
-  // CHECK: %TestVar = alloca i32 addrspace(4)*, align 8
-  // CHECK: %TestVar.ascast = addrspacecast i32 addrspace(4)** %TestVar to i32 addrspace(4)* addrspace(4)*
+  // CHECK: %TestVar = alloca ptr addrspace(4), align 8
+  // CHECK: %TestVar.ascast = addrspacecast ptr %TestVar to ptr addrspace(4)
   // CHECK: %[[ALLOCA:[0-9]+]] = alloca i8, i64 1, align 8
-  // CHECK: %[[ADDRSPCAST:[0-9]+]] = addrspacecast i8* %[[ALLOCA]] to i8* addrspace(4)*
-  // CHECK: %[[BITCAST:[0-9]+]] = bitcast i8* addrspace(4)* %[[ADDRSPCAST]] to i32 addrspace(4)*
-  // CHECK: store i32 addrspace(4)* %[[BITCAST]], i32 addrspace(4)* addrspace(4)* %TestVar.ascast, align 8
+  // CHECK: %[[ADDRSPCAST:[0-9]+]] = addrspacecast ptr %[[ALLOCA]] to ptr addrspace(4)
+  // CHECK: store ptr addrspace(4) %[[ADDRSPCAST]], ptr addrspace(4) %TestVar.ascast, align 8
   int *TestVar = (int *)__builtin_alloca(1);
 }

clang/test/CodeGenSYCL/no_opaque_address-space-builtin-alloca.cpp

@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -triple spir64-unknown-linux -fsycl-is-device -disable-llvm-passes -no-opaque-pointers -emit-llvm -x c++ %s -o - | FileCheck %s
+
+// Test to verify that address space cast is generated correctly for __builtin_alloca
+
+__attribute__((sycl_device)) void foo() {
+  // CHECK: %TestVar = alloca i32 addrspace(4)*, align 8
+  // CHECK: %TestVar.ascast = addrspacecast i32 addrspace(4)** %TestVar to i32 addrspace(4)* addrspace(4)*
+  // CHECK: %[[ALLOCA:[0-9]+]] = alloca i8, i64 1, align 8
+  // CHECK: %[[ADDRSPCAST:[0-9]+]] = addrspacecast i8* %[[ALLOCA]] to i8 addrspace(4)*
+  // CHECK: %[[BITCAST:[0-9]+]] = bitcast i8 addrspace(4)* %[[ADDRSPCAST]] to i32 addrspace(4)*
+  // CHECK: store i32 addrspace(4)* %[[BITCAST]], i32 addrspace(4)* addrspace(4)* %TestVar.ascast, align 8
+  int *TestVar = (int *)__builtin_alloca(1);
+}