[EnzymeExt] tape_type error

[michel2323]

printall.log Getting this error

ERROR: BoundsError: attempt to access 0-element Vector{LLVM.LLVMType} at index [1]
Stacktrace:
  [1] getindex
    @ ./essentials.jl:13 [inlined]
  [2] call!(builder::LLVM.IRBuilder, rt::GPUCompiler.Runtime.RuntimeMethodInstance, args::Vector{LLVM.ConstantExpr})
    @ GPUCompiler /disk/mschanen/julia_depot/packages/GPUCompiler/Y4hSX/src/rtlib.jl:39
  [3] emit_exception!(builder::LLVM.IRBuilder, name::String, inst::LLVM.UnreachableInst)
    @ GPUCompiler /disk/mschanen/julia_depot/packages/GPUCompiler/Y4hSX/src/irgen.jl:219
  [4] emit_error(B::LLVM.IRBuilder, orig::LLVM.UnreachableInst, string::String)
    @ Enzyme.Compiler /disk/mschanen/julia_depot/dev/Enzyme/src/compiler.jl:1647
  [5] codegen(output::Symbol, job::GPUCompiler.CompilerJob{…}; libraries::Bool, deferred_codegen::Bool, optimize::Bool, toplevel::Bool, strip::Bool, validate::Bool, only_entry::Bool, parent_job::GPUCompiler.CompilerJob{…})
    @ Enzyme.Compiler /disk/mschanen/julia_depot/dev/Enzyme/src/compiler.jl:5912
  [6] codegen
    @ /disk/mschanen/julia_depot/dev/Enzyme/src/compiler.jl:5143 [inlined]
  [7] (::Enzyme.var"#70#71"{GPUCompiler.CompilerJob{…}, UInt64, GPUCompiler.CompilerJob{…}})(ctx::LLVM.Context)
    @ Enzyme /disk/mschanen/julia_depot/dev/Enzyme/src/Enzyme.jl:761
  [8] JuliaContext(f::Enzyme.var"#70#71"{GPUCompiler.CompilerJob{…}, UInt64, GPUCompiler.CompilerJob{…}}; kwargs::@Kwargs{})
    @ GPUCompiler /disk/mschanen/julia_depot/packages/GPUCompiler/Y4hSX/src/driver.jl:52
  [9] JuliaContext
    @ /disk/mschanen/julia_depot/packages/GPUCompiler/Y4hSX/src/driver.jl:42 [inlined]
 [10] tape_type(::GPUCompiler.CompilerJob{…}, ::EnzymeCore.ReverseModeSplit{…}, ::Type{…}, ::Type{…}, ::Type{…}, ::Type{…}, ::Type{…})
    @ Enzyme /disk/mschanen/julia_depot/dev/Enzyme/src/Enzyme.jl:760
 [11] _create_tape_kernel(::KernelAbstractions.Kernel{…}, ::Val{…}, ::Type, ::Type, ::Tuple{…}, ::KernelAbstractions.NDIteration.NDRange{…}, ::Duplicated{…}, ::Vararg{…})
    @ EnzymeExt /disk/mschanen/julia_depot/dev/KernelAbstractions/ext/EnzymeExt.jl:146

when running

using KernelAbstractions
using CUDA
using Enzyme
using Adapt

@kernel function stencil_kernel!(y, x)
    i = @index(Global, Linear)
    y[i] = x[i]
end

function stencil!(y, x, backend)
    stencil_kernel!(backend, 64)(y, x, ndrange=64)
end

function driver!(y,x, backend)
    stencil!(y, x, backend)
    return nothing
end

function primal(backend)
    x = adapt(backend, ones(64))
    y = adapt(backend, zeros(64))

    driver!(y, x, backend)

    return all(y .== 1.0)
end

function adjoint(backend)
    x = adapt(backend, ones(64))
    y = adapt(backend, zeros(64))

    dx = adapt(backend, zeros(64))
    dy = adapt(backend, ones(64))

    autodiff(Reverse, driver!, Const, Duplicated(y,dy), Duplicated(x,dx), Const(backend))
    return all(dx .== 1.0)
end

primal(CPU())
primal(CUDABackend())

@time adjoint(CPU())
# BoundsError: attempt to access 0-element Vector{LLVM.LLVMType} at index [1]
# Enzyme.Compiler /disk/mschanen/julia_depot/dev/Enzyme/src/compiler.jl:5912
# emit_error(b, term, "Enzyme: The original primal code hits this error condition, thus differentiating it does not make sense")
@time adjoint(CUDABackend())

It seems to crash at:

# Enzyme.Compiler /disk/mschanen/julia_depot/dev/Enzyme/src/compiler.jl:5912
emit_error(b, term, "Enzyme: The original primal code hits this error condition, thus differentiating it does not make sense")

However both the CUDABackend() original primal as well as the CPU reverse run successfully.

[wsmoses]

Looks like the same one I found in https://github.com/JuliaGPU/GPUCompiler.jl/issues/596

[wsmoses]

Underlying cause from Enzyme side here should now be resolved.

However, the fact this is hit also implies the Enzyme KA rule was never hit, which is bad.

cc @vchuravy

[michel2323]

What do you mean by never hit? It hit the rules for the tests . Or at least the code in the EnzymeExt . Enzyme would crash without the rules.

Edit: Confirming it's resolved.