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Int128 support #974

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maleadt opened this issue Jun 14, 2021 · 4 comments
Open

Int128 support #974

maleadt opened this issue Jun 14, 2021 · 4 comments
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cuda kernels Stuff about writing CUDA kernels. enhancement New feature or request

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@maleadt
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maleadt commented Jun 14, 2021

CUDA GPUs do not natively support Int128 operations. LLVM supports lowering code that works with Int128, https://reviews.llvm.org/rGb9fc48da832654a2b486adaa790ceaa6dba94455, but requires compiler intrinsics for many operations:

julia> using CUDA

julia> x = widen.(CuArray(rand(Int64, 10)))
10-element CuArray{Int128, 1}:
  ...

julia> .÷(x, x)
ERROR: LLVM error: Undefined external symbol "__divti3"

With https://reviews.llvm.org/D34708, it should be possible to resolve those intrinsics in the current module, so we can just add them to our runtime library.
@maleadt maleadt added enhancement New feature or request cuda kernels Stuff about writing CUDA kernels. labels Jun 14, 2021
@maleadt
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maleadt commented Jun 14, 2021

Alternatively, we could build compiler-rt for NVPTX and ship that in CUDA.jl like we do with libdevice.

@maleadt maleadt mentioned this issue Apr 27, 2024
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@maleadt
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maleadt commented Apr 27, 2024

Another MWE from #793:

julia> using CUDA

julia> A = zeros(3) |> CuArray
3-element CuArray{Float64, 1}:
 0.0
 0.0
 0.0

julia> A .= UInt128(5)

@nsajko
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nsajko commented Jan 25, 2025

Another one:

CUDA.fill(Int128(7),    1000)  # seems to work
CUDA.fill((Int128(7),), 1000)  # segfaults in LLVM with both Julia v1.11 and Julia v1.12

MRE:

./julia-6cd750ddf7/bin/julia -g2 -e 'using CUDA; CUDA.fill((Int128(7),), 1000)'

Segfault backtrace:

[16353] signal 11 (1): Segmentation fault
in expression starting at none:1
_ZN4llvm12SelectionDAG22FoldConstantArithmeticEjRKNS_5SDLocENS_3EVTENS_8ArrayRefINS_7SDValueEEE at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZN4llvm12SelectionDAG7getNodeEjRKNS_5SDLocENS_3EVTENS_7SDValueENS_11SDNodeFlagsE at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZL16getCopyFromPartsRN4llvm12SelectionDAGERKNS_5SDLocEPKNS_7SDValueEjNS_3MVTENS_3EVTEPKNS_5ValueES5_St8optionalIjESD_INS_3ISD8NodeTypeEE.isra.0 at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZN4llvm16SelectionDAGISel14LowerArgumentsERKNS_8FunctionE at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZN4llvm16SelectionDAGISel20SelectAllBasicBlocksERKNS_8FunctionE at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZN4llvm16SelectionDAGISel20runOnMachineFunctionERNS_15MachineFunctionE.part.0 at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZN4llvm19MachineFunctionPass13runOnFunctionERNS_8FunctionE.part.0 at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZN4llvm13FPPassManager13runOnFunctionERNS_8FunctionE at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZN4llvm13FPPassManager11runOnModuleERNS_6ModuleE at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZN4llvm6legacy15PassManagerImpl3runERNS_6ModuleE at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZL21LLVMTargetMachineEmitP23LLVMOpaqueTargetMachineP16LLVMOpaqueModuleRN4llvm17raw_pwrite_streamE19LLVMCodeGenFileTypePPc at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
LLVMTargetMachineEmitToMemoryBuffer at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
LLVMTargetMachineEmitToMemoryBuffer at /home/nsajko/.julia/packages/LLVM/b3kFs/lib/18/libLLVM.jl:11531 [inlined]
emit at /home/nsajko/.julia/packages/LLVM/b3kFs/src/targetmachine.jl:118
mcgen at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/mcgen.jl:75 [inlined]
mcgen at /home/nsajko/.julia/packages/CUDA/1kIOw/src/compiler/compilation.jl:127
jfptr_mcgen_16086 at /home/nsajko/.julia/compiled/v1.12/CUDA/oWw5k_MfWR6.so (unknown line)
macro expansion at /home/nsajko/.julia/packages/TimerOutputs/6KVfH/src/TimerOutput.jl:253 [inlined]
macro expansion at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/driver.jl:403 [inlined]
macro expansion at /home/nsajko/.julia/packages/TimerOutputs/6KVfH/src/TimerOutput.jl:253 [inlined]
#emit_asm#145 at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/driver.jl:400
emit_asm at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/driver.jl:393 [inlined]
#codegen#109 at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/driver.jl:120
codegen at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/driver.jl:82 [inlined]
#compile#108 at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/driver.jl:79
compile at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/driver.jl:74
#compile##0 at /home/nsajko/.julia/packages/CUDA/1kIOw/src/compiler/compilation.jl:250 [inlined]
#JuliaContext#107 at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/driver.jl:34
jfptr_YY.JuliaContextYY.107_14990 at /home/nsajko/.julia/compiled/v1.12/CUDA/oWw5k_MfWR6.so (unknown line)
JuliaContext at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/driver.jl:25
compile at /home/nsajko/.julia/packages/CUDA/1kIOw/src/compiler/compilation.jl:249
actual_compilation at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/execution.jl:237
jfptr_actual_compilation_14810 at /home/nsajko/.julia/compiled/v1.12/CUDA/oWw5k_MfWR6.so (unknown line)
cached_compilation at /home/nsajko/.julia/packages/GPUCompiler/Nxf8r/src/execution.jl:151
macro expansion at /home/nsajko/.julia/packages/CUDA/1kIOw/src/compiler/execution.jl:380 [inlined]
macro expansion at ./lock.jl:376 [inlined]
#cufunction#708 at /home/nsajko/.julia/packages/CUDA/1kIOw/src/compiler/execution.jl:375
cufunction at /home/nsajko/.julia/packages/CUDA/1kIOw/src/compiler/execution.jl:372
unknown function (ip: 0x790eba793a7c) at (unknown file)
macro expansion at /home/nsajko/.julia/packages/CUDA/1kIOw/src/compiler/execution.jl:112 [inlined]
#_#3 at /home/nsajko/.julia/packages/CUDA/1kIOw/src/CUDAKernels.jl:103
jl_apply at /cache/build/tester-demeter6-14/julialang/julia-master/src/julia.h:2245 [inlined]
do_apply at /cache/build/tester-demeter6-14/julialang/julia-master/src/builtins.c:839
Kernel at /home/nsajko/.julia/packages/CUDA/1kIOw/src/CUDAKernels.jl:89
fill! at /home/nsajko/.julia/packages/GPUArrays/Mot2g/src/host/construction.jl:22
fill at /home/nsajko/.julia/packages/CUDA/1kIOw/src/array.jl:777
unknown function (ip: 0x790eba78d9b9) at (unknown file)
jl_apply at /cache/build/tester-demeter6-14/julialang/julia-master/src/julia.h:2245 [inlined]
do_call at /cache/build/tester-demeter6-14/julialang/julia-master/src/interpreter.c:125
eval_value at /cache/build/tester-demeter6-14/julialang/julia-master/src/interpreter.c:243
eval_stmt_value at /cache/build/tester-demeter6-14/julialang/julia-master/src/interpreter.c:194 [inlined]
eval_body at /cache/build/tester-demeter6-14/julialang/julia-master/src/interpreter.c:684
jl_interpret_toplevel_thunk at /cache/build/tester-demeter6-14/julialang/julia-master/src/interpreter.c:889
jl_toplevel_eval_flex at /cache/build/tester-demeter6-14/julialang/julia-master/src/toplevel.c:1102
jl_toplevel_eval_flex at /cache/build/tester-demeter6-14/julialang/julia-master/src/toplevel.c:1042
jl_toplevel_eval_flex at /cache/build/tester-demeter6-14/julialang/julia-master/src/toplevel.c:1042
ijl_toplevel_eval at /cache/build/tester-demeter6-14/julialang/julia-master/src/toplevel.c:1114
ijl_toplevel_eval_in at /cache/build/tester-demeter6-14/julialang/julia-master/src/toplevel.c:1159
eval at ./boot.jl:486
exec_options at ./client.jl:295
_start at ./client.jl:557
jfptr__start_57584.1 at /home/nsajko/tmp/jl/jl/julia-6cd750ddf7/lib/julia/sys.so (unknown line)
jl_apply at /cache/build/tester-demeter6-14/julialang/julia-master/src/julia.h:2245 [inlined]
true_main at /cache/build/tester-demeter6-14/julialang/julia-master/src/jlapi.c:924
jl_repl_entrypoint at /cache/build/tester-demeter6-14/julialang/julia-master/src/jlapi.c:1084
main at /cache/build/tester-demeter6-14/julialang/julia-master/cli/loader_exe.c:58
unknown function (ip: 0x790ec19f5e07) at /usr/lib/libc.so.6
__libc_start_main at /usr/lib/libc.so.6 (unknown line)
unknown function (ip: 0x4010b8) at /workspace/srcdir/glibc-2.17/csu/../sysdeps/x86_64/start.S
Allocations: 22607865 (Pool: 22607426; Big: 439); GC: 27
Segmentation fault (core dumped)

@maleadt
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maleadt commented Jan 27, 2025

This is probably a selection failure; would be good to run with LLVM assertions enabled.

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