[llvm-dev] LLVM FunctionType cannot be returned as VectorType?

Jia Yu via llvm-dev llvm-dev at lists.llvm.org
Mon Jul 23 03:01:46 PDT 2018


Hi Stefan,

Thank you very much for answering my question!

I followed your suggestion but the function still cannot return the correct
result. I also set target-feature attributes for my function. I am using
LLVM 6.0.

It only prints out some random large numbers but the correct answer is
supposed to be all 0.

Can you please help me figure out what's going on here? Any help will be
greatly appreciated.

///////////////////////////////////////////////////////////////////////////////////////////

My function prototype definition:

auto vectorDataType = VectorType::get(IntegerType::getIntNTy(TheContext,
64), 4);
                    std::vector<Type *> vecArguments;
                    for (Uint64 nodeId = startOfLeaves; nodeId < numNodes;
++nodeId) {
                        vecArguments.push_back(vectorDataType);
                    }
                    proto = FunctionType::get(vectorDataType,//int64*4 =
__m256i
                                              vecArguments, false);

////////////////////////////////////////////////////////////
///////////////////////////////

The generated IR:

define <4 x i64> @tpchq6(<4 x i64> %leaf7, <4 x i64> %leaf8, <4 x i64>
%leaf9, <4 x i64> %leaf10, <4 x i64> %leaf11, <4 x i64> %leaf12, <4 x i64>
%leaf13, <4 x i64> %leaf14) #0 {
entry:
  %addtmp = add <4 x i64> %leaf8, %leaf7
  %addtmp1 = add <4 x i64> %addtmp, %leaf9
  %addtmp4 = add <4 x i64> %addtmp1, %leaf10
  %addtmp2 = add <4 x i64> %addtmp4, %leaf11
  %addtmp3 = add <4 x i64> %addtmp2, %leaf12
  %addtmp5 = add <4 x i64> %addtmp3, %leaf13
  %addtmp6 = add <4 x i64> %addtmp5, %leaf14
  ret <4 x i64> %addtmp6
}

///////////////////////////////////////////////////////////////////////////////////////////

My JIT function call:

using VecInt = int64_t[4];

auto function = (int64_t *(*)(
                            VecInt
                            , VecInt
                            , VecInt
                            , VecInt
                            , VecInt
                            , VecInt
                            , VecInt
                            , VecInt

))(TheExecutionEngine->getFunctionAddress(TheFunction->getName().str()));

VecInt argsX = {0,0,0,0};
int64_t* result = function(argsX,argsX,argsX,argsX,argsX,argsX,argsX,argsX);


////////////////////////////////////////////////////////////
///////////////////////////////
My output result:
422162285262848 562251371602737 843692813695832 422162285262848

It only prints out some random large numbers but the correct answer is
supposed to be all 0.

////////////////////////////////////////////////////////////
///////////////////////////////

Thanks,
Jia

------------------------------------

Jia Yu,

Ph.D. Student in Computer Science

Arizona State University <http://www.asu.edu/>


On Sun, Jul 22, 2018 at 8:51 AM Stefan Gränitz <stefan.graenitz at gmail.com>
wrote:

> Hi Jia
>
> I don't think this is a problem with the ExecutionEngine. Your problem
> comes from the confusion of the "Vector Type" in LLVM IR [1] with the
> "std::vector" data structure in the C++ STL. While there is no direct
> relation between the two, you should be able to use a std::vector to
> provide the input for the <4 x i61> Vector Type by passing the
> std::vector's raw data [3].
>
> However, it would be easier with something like this:
>
> using VecInt = int64[4];
> VecInt args0 { 0, 1, 2, 3 };
> ...
> VecInt result = function(args0, ...);
>
> Btw.: Note that you may need to set target-feature attributes for your
> function like so: [3]
>
> Hope it helps.
>
> Cheers,
> Stefan
>
> [1] https://llvm.org/docs/LangRef.html#vector-type
> [2] https://en.cppreference.com/w/cpp/container/vector
> [3] https://en.cppreference.com/w/cpp/container/vector/data
> [4]
> https://github.com/weliveindetail/DecisionTreeCompiler/blob/master/compiler/DecisionTreeCompiler.cpp#L83
>
> Am 20.07.18 um 02:02 schrieb Jia Yu via llvm-dev:
>
> Dear all,
>
> I am using LLVM C++ API to generate some code. In particular, I am dealing
> with AVX2 SIMD API which uses __m256i.
>
> My function input types a set of vectors and return type is also a vector.
>
>
> ///////////////////////////////////////////////////////////////////////////////////////////
>
> arguments.push_back(VectorType::get(IntegerType::getIntNTy(TheContext, 64),
> 4));//int64*4 = __m256i
>                 FunctionType * proto =
> FunctionType::get(VectorType::get(IntegerType::getIntNTy(TheContext, 64),
> 4),//int64*4 = __m256i
>                                                          arguments, false);
>
> ///////////////////////////////////////////////////////////////////////////////////////////
>
> I can successfully use this way to produce the IR of my function properly
> like this:
>
> ///////////////////////////////////////////////////////////////////////////////////////////
>
> define <4 x i64> @tpchq6(<4 x i64> %leaf7, <4 x i64> %leaf8, <4 x i64>
> %leaf9, <4 x i64> %leaf10, <4 x i64> %leaf11, <4 x i64> %leaf12, <4 x i64>
> %leaf13, <4 x i64> %leaf14) {
>
> entry:
>
>   %addtmp = add <4 x i64> %leaf14, %leaf13
>
>   %leaf8.neg = sub <4 x i64> zeroinitializer, %leaf8
>
>   %xortmp = xor <4 x i64> %addtmp, %leaf11
>
>   %addtmp1 = add <4 x i64> %leaf8.neg, %leaf7
>
>   %subtmp = add <4 x i64> %addtmp1, %leaf9
>
>   %addtmp2 = add <4 x i64> %subtmp, %leaf10
>
>   %addtmp3 = add <4 x i64> %addtmp2, %xortmp
>
>   ret <4 x i64> %addtmp3
>
> }
>
>
> ///////////////////////////////////////////////////////////////////////////////////////////
>
> However, when I use JIT ExectionEngine to run it, it cannot return the
> Vector type properly. I tried the jit execution engine with non-vector
> return like int64, it works fine.
>
> My code is as follows: It always tells me segment fault
>
> ///////////////////////////////////////////////////////////////////////////////////////////
> // Define the input/output data type in LLVM function
>  typedef std::vector<int64_t> VecInt;
>
> auto function = reinterpret_cast<VecInt (*)(VecInt , VecInt, VecInt,
> VecInt, VecInt, VecInt, VecInt,
> VecInt)>(TheExecutionEngine->getFunctionAddress(TheFunction->getName().str()));
> VecInt result =
> function(functionCallArgs[0],functionCallArgs[1],functionCallArgs[2],functionCallArgs[3],
>
> functionCallArgs[4],functionCallArgs[5],functionCallArgs[6],functionCallArgs[7]);
>
> std::cout<<"result size "<< result.size()<<"\n";
>
> ///////////////////////////////////////////////////////////////////////////////////////////
>
>
> Can someone tell me whether this is the correct way to retrieve the vector
> return type? Or is the vector type return supported?
>
> Thanks,
> Jia Yu
>
>
>
>
> _______________________________________________
> LLVM Developers mailing listllvm-dev at lists.llvm.orghttp://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
> -- https://weliveindetail.github.io/blog/https://cryptup.org/pub/stefan.graenitz@gmail.com
>
>
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