Unknown binary operator

[MasonProtter]

Here's a MWE for an error I experienced:

julia> using Enzyme

julia> function f(x)
           y = (x + im)*(x - im)
           real(y)
       end
f (generic function with 1 method)

julia> autodiff(f, Active(2.0))
4.0julia> function g(x)
           y = (x + im)*(1 - im*x)
           real(y)
       end
g (generic function with 1 method)

julia> autodiff(g, Active(2.0))define dso_local double @preprocess_julia_overdub_1835(double) local_unnamed_addr {
top:
  %1 = bitcast double %0 to i64
  %2 = and i64 %1, -9223372036854775808
  %3 = bitcast i64 %2 to double
  %4 = fsub double 1.000000e+00, %3
  %5 = fmul double %4, %0
  %6 = fadd double %5, %0
  ret double %6
} constantinst[  %1 = bitcast double %0 to i64] = 0 val:0 type: {[-1]:Float@double}
 constantinst[  %2 = and i64 %1, -9223372036854775808] = 0 val:0 type: {[-1]:Float@double}
 constantinst[  ret double %6] = 1 val:1 type: {}
 constantinst[  %3 = bitcast i64 %2 to double] = 0 val:0 type: {[-1]:Float@double}
 constantinst[  %4 = fsub double 1.000000e+00, %3] = 0 val:0 type: {[-1]:Float@double}
 constantinst[  %5 = fmul double %4, %0] = 0 val:0 type: {[-1]:Float@double}
 constantinst[  %6 = fadd double %5, %0] = 0 val:0 type: {[-1]:Float@double}
cannot handle unknown binary operator:   %2 = and i64 %1, -9223372036854775808
ERROR: LLVM error: unknown binary operator
Stacktrace:
 [1] handle_error(::Cstring) at /home/mason/.julia/packages/LLVM/dVU7J/src/core/context.jl:105

[wsmoses]

Oh this is a pretty interesting bithack that Julia seems to have emitted (signed zero(x) == and(x, MAGIC NUM)).

Usually horrible bithacks of active values tend not to be handled in Enzyme automatically but this one should be easy to ensure happens.

I'll make a patch to Enzyme proper and we'll propagate that to Enzyme.jl shortly

[wsmoses]

Merged in #31