Add --only-needed flag to llvm-link for AMDGCN

Add the --only-needed flag for AMDGCN when linking against devicelib.

Fixes several test cases that use kernel bundles.

Author: Martin Wehking

clang/lib/Driver/ToolChains/SYCL.cpp

@@ -579,6 +579,7 @@ const char *SYCL::Linker::constructLLVMLinkCommand(
     auto isSYCLDeviceLib = [&](const InputInfo &II) {
       const ToolChain *HostTC = C.getSingleOffloadToolChain<Action::OFK_Host>();
       const bool IsNVPTX = this->getToolChain().getTriple().isNVPTX();
+      const bool IsAMDGCN = this->getToolChain().getTriple().isAMDGCN();
       const bool IsFPGA = this->getToolChain().getTriple().isSPIR() &&
                           this->getToolChain().getTriple().getSubArch() ==
                               llvm::Triple::SPIRSubArch_fpga;
@@ -598,6 +599,8 @@ const char *SYCL::Linker::constructLLVMLinkCommand(
       // NativeCPU links against libclc (libspirv)
       if (IsSYCLNativeCPU && InputFilename.contains("libspirv"))
         return true;
+      if (IsAMDGCN && InputFilename.starts_with("devicelib-"))
+        return true;
       // NVPTX links against our libclc (libspirv), our libdevice (devicelib),
       // and the CUDA libdevice
       if (IsNVPTX && (InputFilename.starts_with("devicelib-") ||