[clang] [llvm] [AMDGPU] Enable OpenCL hostcall printf (WIP) (PR #72556)

[Sameer Sahasrabuddhe via cfe-commits]

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@@ -198,15 +213,31 @@ RValue CodeGenFunction::EmitAMDGPUDevicePrintfCallExpr(const CallExpr *E) {
     }
 
     llvm::Value *Arg = A.getRValue(*this).getScalarVal();
+    if (isString(A.getType().getTypePtr()) && CGM.getLangOpts().OpenCL)
+      Arg = Builder.CreateAddrSpaceCast(Arg, CGM.Int8PtrTy);
     Args.push_back(Arg);
   }
 
-  llvm::IRBuilder<> IRB(Builder.GetInsertBlock(), Builder.GetInsertPoint());
-  IRB.SetCurrentDebugLocation(Builder.getCurrentDebugLocation());
+  auto PFK = CGM.getTarget().getTargetOpts().AMDGPUPrintfKindVal;
+  bool isBuffered =
+       (PFK == clang::TargetOptions::AMDGPUPrintfKind::Buffered);
+
+  StringRef FmtStr;
+  if (llvm::getConstantStringInfo(Args[0], FmtStr)) {
+    if (FmtStr.empty())
+      FmtStr = StringRef("", 1);
+  } else {
+    if (CGM.getLangOpts().OpenCL) {
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ssahasra wrote:

The diagnostic should be replaced with an assert() or an llvm_unreachable(). The OpenCL spec says that the format string should be resolvable at compile time, but this is not the right place to check that. By now, the frontend or sema should have rejected the program as ill-formed.

https://github.com/llvm/llvm-project/pull/72556