[LLVMdev] UNREACHABLE executed! error while trying to generate PTX

[Justin Holewinski]

I noticed you're using cuda_runtime.h in the source file.  Where are you
getting this file?  From the CUDA toolkit?

Since the error is in the back-end, can you just post the .ll or .bc file
you are trying to compile?


On Mon, Mar 18, 2013 at 12:42 AM, upit <uday_pitambare at yahoo.com> wrote:

> I am trying to generate PTX code for 'nbody' sample program's kernel
> (nbody_kernel.cu) using clang/LLVM version 3.2. The nbody CUDA program is
> available in Nvidia's SDK.
>
> I am referring to https://github.com/jholewinski/llvm-ptx-samples project.
>
> Following are my commands,
>
> clang++ -O4 -S -I/usr/local/cuda/include -emit-llvm -target nvptx64
> nbody_kernel.cu -o nbody_kernel.ll
>
> opt -O3 -loop-unroll -unroll-allow-partial nbody_kernel.ll -o
> nbody_kernel.ll
>
> llc nbody_kernel.ll -o nbody_kernel.ptx
>
> After execution of the last command(llc) I get a UNREACHABLE executed!
> error
> with the following stack trace
>
> [DEVICE-C++] nbody.kernel.cpp
> unexpected address space
> UNREACHABLE executed at
> /home/pratnali/LLVM/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp:1317!
> 0  libLLVM-3.3svn.so 0x00007f3857bdf0cb
> llvm::sys::PrintStackTrace(_IO_FILE*) + 43
> 1  libLLVM-3.3svn.so 0x00007f3857bde74a
> 2  libpthread.so.0   0x00007f3856c3c460
> 3  libc.so.6         0x00007f3855a90b15 gsignal + 53
> 4  libc.so.6         0x00007f3855a91f96 abort + 390
> 5  libLLVM-3.3svn.so 0x00007f3857bc30f7
> llvm::llvm_unreachable_internal(char
> const*, char const*, unsigned int) + 359
> 6  libLLVM-3.3svn.so 0x00007f385722967d
> 7  libLLVM-3.3svn.so 0x00007f385722b6d7
> 8  libLLVM-3.3svn.so 0x00007f3857341723
> llvm::FPPassManager::doInitialization(llvm::Module&) + 99
> 9  libLLVM-3.3svn.so 0x00007f385734639d
> llvm::MPPassManager::runOnModule(llvm::Module&) + 205
> 10 libLLVM-3.3svn.so 0x00007f3857349b7c
> llvm::PassManagerImpl::run(llvm::Module&) + 268
> 11 llc               0x000000000040b534
> 12 llc               0x000000000040d131 main + 465
> 13 libc.so.6         0x00007f3855a7d4bd __libc_start_main + 253
> 14 llc               0x0000000000406e59
> Stack dump:
> 0.      Program arguments: llc nbody.kernel.ll -o nbody.kernel.ptx
> make: *** [nbody.kernel.ptx] Aborted
>
>
> I replaced the global indexes like for e.g threadIdx.x with
> __builtin_ptx_read_tid_x() and others. There are no problems in generating
> LLVM IR (i.e .ll). The error pops up while trying to generate PTX from the
> IR using llc.
>
> Any pointers on what might be going on here ? Will appreciate any help in
> going forward
>
> I have attached my program and observations in a README here.
> LLVM_PTX_nbody.tar.gz
> <http://llvm.1065342.n5.nabble.com/file/n56026/LLVM_PTX_nbody.tar.gz>
>
> You can easily reproduce the problem using this.
>
>
>
>
> --
> View this message in context:
> http://llvm.1065342.n5.nabble.com/UNREACHABLE-executed-error-while-trying-to-generate-PTX-tp56026.html
> Sent from the LLVM - Dev mailing list archive at Nabble.com.
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>



-- 

Thanks,

Justin Holewinski
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