[clang] [llvm] [Driver][SYCL] Add initial SYCL offload compilation support (PR #107493)

[Aaron Ballman via cfe-commits]

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@@ -5116,11 +5123,34 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   if (const Arg *PF = Args.getLastArg(options::OPT_mprintf_kind_EQ))
     PF->claim();
 
-  if (Args.hasFlag(options::OPT_fsycl, options::OPT_fno_sycl, false)) {
-    CmdArgs.push_back("-fsycl-is-device");
+  Arg *SYCLStdArg = Args.getLastArg(options::OPT_sycl_std_EQ);
 
-    if (Arg *A = Args.getLastArg(options::OPT_sycl_std_EQ)) {
-      A->render(Args, CmdArgs);
+  if (IsSYCL) {
+    if (IsSYCLDevice) {
+      // Host triple is needed when doing SYCL device compilations.
+      llvm::Triple AuxT = C.getDefaultToolChain().getTriple();
+      std::string NormalizedTriple = AuxT.normalize();
+      CmdArgs.push_back("-aux-triple");
+      CmdArgs.push_back(Args.MakeArgString(NormalizedTriple));
+
+      // We want to compile sycl kernels.
+      CmdArgs.push_back("-fsycl-is-device");
+
+      // Set O2 optimization level by default
+      if (!Args.getLastArg(options::OPT_O_Group))
+        CmdArgs.push_back("-O2");
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AaronBallman wrote:

I presume this is okay because "debugging" on the device is basically not a thing? Do we expect that debuggers will get support for debugging devices and thus might not want this as a default?

https://github.com/llvm/llvm-project/pull/107493