[LLVMdev] Adding intrinsic with variable argument list HOWTO.

[Mikael Lepistö]

Hi, I've been hitting my head to wall two days now. This is practically 
my first contact with InstrInfo.td files. Is there any tutorial how to 
make this kind of stuff? Or should I just keep on studying Sparc and 
other backends?

So I added new intrinsic to llvm/include/llvm/TCEInstrinsics.td:

def int_tce_customop : 
    Intrinsic<[llvm_void_ty, llvm_ptr_ty, llvm_vararg_ty], [], 
"llvm.tce.customop">;

I made opt pass that converts __custom_op() functions to calls to 
llvm.tce.customop calls.

shell> grep llvm.tce.customop hello2.ll
        tail call void (i8*, ...)* @llvm.tce.customop( i8* getelementptr 
([7 x i8]* @.str, i32 0, i32 0), i32 %tmp78 )
        tail call void (i8*, ...)* @llvm.tce.customop( i8* getelementptr 
([7 x i8]* @.str, i32 0, i32 0), i32 10 )
        tail call void (i8*, ...)* @llvm.tce.customop( i8* getelementptr 
([7 x i8]* @.str, i32 0, i32 0), i32 %tmp12 )
declare void @llvm.tce.customop(i8*, ...)

No I need to add code to llvm/lib/Target/TCE/TCEInstrInfo.td, for 
recognizing that variable argument intrinsic and I have no idea how it's 
done. Right now I'm trying following:

def CustomOpParams : SDTypeProfile<0,2,[]>;

def customop       : SDNode<"ISD::INTRINSIC_VOID", CustomOpParams>;

def : Pat<(customop tglobaladdr:$dst,iPTR:$vararg),
          (int_tce_customop tglobaladdr:$dst, iAny:$vararg)>;

def : Pat<(call texternalsym:$dst,iAny:$vararg),
          (int_tce_customop texternalsym:$dst, iAny:$vararg)>;


but compilation gives following error:

isVoid:void anonymous.52:       (intrinsic_void:void 197:iPTR, 
(tglobaladdr:iPTR):$dst, isVoid:void)
/home/elhigu/llvm-install/llvm/Release/bin/tblgen: In anonymous.52: Type 
inference contradiction found in node!

Mikael Lepistö