Segmentation fault when cloning a sparse matrix

The following program:

using SparseArrays

function go()
    A = sprandn(10, 10, 0.1)
    v = Vector(undef, 2)
    for i = 1:2
        v[i] = SparseMatrixCSC(A.m, A.n, A.colptr, A.rowval, copy(A.nzval))
    end
end

@time go()

Results in a segmentation fault for me:

signal (11): Segmentation fault: 11
in expression starting at no file:0
_ZN4llvm9LiveRange4joinERS0_PKiS3_RNS_15SmallVectorImplIPNS_6VNInfoEEE at /Applications/Julia-0.7.app/Contents/Resources/julia/lib/julia/libLLVM.dylib (unknown line)
_ZN12_GLOBAL__N_117RegisterCoalescer8joinCopyEPN4llvm12MachineInstrERb at /Applications/Julia-0.7.app/Contents/Resources/julia/lib/julia/libLLVM.dylib (unknown line)
_ZN12_GLOBAL__N_117RegisterCoalescer20copyCoalesceWorkListEN4llvm15MutableArrayRefIPNS1_12MachineInstrEEE at /Applications/Julia-0.7.app/Contents/Resources/julia/lib/julia/libLLVM.dylib (unknown line)
_ZN12_GLOBAL__N_117RegisterCoalescer20runOnMachineFunctionERN4llvm15MachineFunctionE at /Applications/Julia-0.7.app/Contents/Resources/julia/lib/julia/libLLVM.dylib (unknown line)
_ZN4llvm19MachineFunctionPass13runOnFunctionERNS_8FunctionE at /Applications/Julia-0.7.app/Contents/Resources/julia/lib/julia/libLLVM.dylib (unknown line)
_ZN4llvm13FPPassManager13runOnFunctionERNS_8FunctionE at /Applications/Julia-0.7.app/Contents/Resources/julia/lib/julia/libLLVM.dylib (unknown line)
_ZN4llvm13FPPassManager11runOnModuleERNS_6ModuleE at /Applications/Julia-0.7.app/Contents/Resources/julia/lib/julia/libLLVM.dylib (unknown line)
_ZN4llvm6legacy15PassManagerImpl3runERNS_6ModuleE at /Applications/Julia-0.7.app/Contents/Resources/julia/lib/julia/libLLVM.dylib (unknown line)

I’m using Julia 0.7.0 on Mac. If I replace the for loop with v[1] = and v[2] =, the program works. Also, if I use copy(A.colptr) it works. It also works in Julia 0.6.4.

What I’m trying to achieve is to create a few new matrices with the same sparsity pattern as an existing matrix, but with modified values, and in order to save memory I want to reuse the colptr and rowval vectors.

Any idea what’s going on? Perhaps it’s not allowed to reuse the column/row vectors this way?

This should not happen, can you open an issue with this example? https://github.com/JuliaLang/julia/issues/new

Alright, done: https://github.com/JuliaLang/julia/issues/28913

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