[SYCL][Clang][HIP] Disable macro __CUDA_ARCH__ for AMD hip-platform (#7977)

Fixes #7720

Author: abagusetty

clang/lib/Basic/Targets/AMDGPU.cpp

@@ -415,6 +415,7 @@ void AMDGPUTargetInfo::getTargetDefines(const LangOptions &Opts,
       assert(CanonName.startswith("gfx") && "Invalid amdgcn canonical name");
       Builder.defineMacro(Twine("__") + Twine(CanonName.drop_back(2).upper()) +
                           Twine("__"));
+      Builder.defineMacro("__CUDA_ARCH__", "0");
     }
     if (isAMDGCN(getTriple())) {
       Builder.defineMacro("__amdgcn_processor__",

clang/test/Preprocessor/sycl-macro.cpp

@@ -10,6 +10,7 @@
 // RUN: %clang_cc1 -fno-sycl-id-queries-fit-in-int %s -E -dM | FileCheck \
 // RUN: --check-prefix=CHECK-NO-SYCL_FIT_IN_INT %s
 // RUN: %clang_cc1 %s  -triple nvptx64-nvidia-cuda -target-cpu sm_80 -fsycl-is-device -E -dM | FileCheck --check-prefix=CHECK-CUDA %s
+// RUN: %clang_cc1 %s  -triple amdgcn-amd-amdhsa -target-cpu gfx906 -fsycl-is-device -E -dM | FileCheck --check-prefix=CHECK-HIP %s
 
 // CHECK-NOT:#define __SYCL_DEVICE_ONLY__ 1
 // CHECK-NOT:#define SYCL_EXTERNAL
@@ -33,3 +34,5 @@
 // CHECK-SYCL-ID:#define __SYCL_ID_QUERIES_FIT_IN_INT__ 1
 
 // CHECK-CUDA:#define __CUDA_ARCH__ 800
+
+// CHECK-HIP:#define __CUDA_ARCH__ 0