[clang][AMDGPU][CUDA] Handle __builtin_printf for device printf (#68515)

Previously `__builtin_printf` would result to emitting call to `printf`,
even though directly calling `printf` was translated.

Ref: #68478

Author: Mészáros Gergely

clang/lib/CodeGen/CGBuiltin.cpp

@@ -5710,6 +5710,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
     Value *HalfVal = Builder.CreateLoad(Address);
     return RValue::get(Builder.CreateFPExt(HalfVal, Builder.getFloatTy()));
   }
+  case Builtin::BI__builtin_printf:
   case Builtin::BIprintf:
     if (getTarget().getTriple().isNVPTX() ||
         getTarget().getTriple().isAMDGCN()) {

clang/lib/CodeGen/CGGPUBuiltin.cpp

@@ -136,7 +136,8 @@ RValue EmitDevicePrintfCallExpr(const CallExpr *E, CodeGenFunction *CGF,
                                 llvm::Function *Decl, bool WithSizeArg) {
   CodeGenModule &CGM = CGF->CGM;
   CGBuilderTy &Builder = CGF->Builder;
-  assert(E->getBuiltinCallee() == Builtin::BIprintf);
+  assert(E->getBuiltinCallee() == Builtin::BIprintf ||
+         E->getBuiltinCallee() == Builtin::BI__builtin_printf);
   assert(E->getNumArgs() >= 1); // printf always has at least one arg.
 
   // Uses the same format as nvptx for the argument packing, but also passes

clang/test/CodeGenCUDA/printf-builtin.cu

@@ -0,0 +1,21 @@
+// REQUIRES: x86-registered-target
+// REQUIRES: nvptx-registered-target
+// RUN: %clang_cc1 -triple nvptx64-nvidia-cuda -emit-llvm -disable-llvm-optzns -fno-builtin-printf -fcuda-is-device \
+// RUN:   -o - %s | FileCheck  %s
+
+#define __device__ __attribute__((device))
+
+extern "C" __device__ int printf(const char *format, ...);
+
+// CHECK-LABEL: @_Z4foo1v()
+__device__ int foo1() {
+  // CHECK: call i32 @vprintf
+  // CHECK-NOT: call i32 (ptr, ...) @printf
+  return __builtin_printf("Hello World\n");
+}
+
+// CHECK-LABEL: @_Z4foo2v()
+__device__ int foo2() {
+  // CHECK: call i32 (ptr, ...) @printf
+  return printf("Hello World\n");
+}

clang/test/CodeGenHIP/printf-builtin.hip

@@ -0,0 +1,23 @@
+// REQUIRES: amdgpu-registered-target
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -emit-llvm -disable-llvm-optzns -mprintf-kind=hostcall -fno-builtin-printf -fcuda-is-device \
+// RUN:   -o - %s | FileCheck --check-prefixes=CHECK,HOSTCALL %s
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -emit-llvm -disable-llvm-optzns -mprintf-kind=buffered -fno-builtin-printf -fcuda-is-device \
+// RUN:   -o - %s | FileCheck --check-prefixes=CHECK,BUFFERED %s
+
+#define __device__ __attribute__((device))
+
+extern "C" __device__ int printf(const char *format, ...);
+
+// CHECK-LABEL: @_Z4foo1v()
+__device__ int foo1() {
+  // HOSTCALL: call i64 @__ockl_printf_begin
+  // BUFFERED: call ptr addrspace(1) @__printf_alloc
+  // CHECK-NOT: call i32 (ptr, ...) @printf
+  return __builtin_printf("Hello World\n");
+}
+
+// CHECK-LABEL: @_Z4foo2v()
+__device__ int foo2() {
+  // CHECK: call i32 (ptr, ...) @printf
+  return printf("Hello World\n");
+}