Fix getfield of const (EnzymeAD#1572)

* Fix getfield of const

* fix

* add test

* fixup

src/compiler.jl

@@ -103,6 +103,7 @@ Dict{DataType, Tuple{Symbol, Int, Union{Nothing, Tuple{Symbol, DataType}}}}(
 end
 
 const nofreefns = Set{String}((
+ "ijl_field_index", "jl_field_index",
  "ijl_specializations_get_linfo", "jl_specializations_get_linfo",
  "ijl_gf_invoke_lookup_worlds", "jl_gf_invoke_lookup_worlds",
  "ijl_gc_get_total_bytes", "jl_gc_get_total_bytes",
@@ -183,6 +184,7 @@ const nofreefns = Set{String}((
 ))
 
 const inactivefns = Set{String}((
+ "ijl_field_index", "jl_field_index",
  "ijl_specializations_get_linfo", "jl_specializations_get_linfo",
  "ijl_gf_invoke_lookup_worlds", "jl_gf_invoke_lookup_worlds",
  "ijl_gc_get_total_bytes", "jl_gc_get_total_bytes",
@@ -3258,7 +3260,7 @@ function annotate!(mod, mode)
  end
  end
 
- for fname in ("jl_excstack_state","ijl_excstack_state")
+ for fname in ("jl_excstack_state","ijl_excstack_state", "ijl_field_index", "jl_field_index")
  if haskey(fns, fname)
  fn = fns[fname]
  if LLVM.version().major <= 15

src/rules/typeunstablerules.jl

@@ -606,7 +606,7 @@ function rt_jl_getfield_aug(::Val{NT}, dptr::T, ::Type{Val{symname}}, ::Val{isco
  RT = Core.Typeof(res)
 
  actreg = active_reg_nothrow(RT, Val(nothing))
- if actreg == ActiveState
+ if actreg == ActiveState || (isconst && actreg == MixedState)
  if length(dptrs) == 0
  return Ref{RT}(make_zero(res))
  else
@@ -626,6 +626,16 @@ function rt_jl_getfield_aug(::Val{NT}, dptr::T, ::Type{Val{symname}}, ::Val{isco
  end)...))
  return fval
  end
+ elseif isconst
+ if length(dptrs) == 0
+ return make_zero(res)
+ else
+ fval = NT((res, (ntuple(Val(length(dptrs))) do i
+ Base.@_inline_meta
+ make_zero(res)
+ end)...))
+ return fval
+ end
  else
  if length(dptrs) == 0
  return res
@@ -648,7 +658,7 @@ function idx_jl_getfield_aug(::Val{NT}, dptr::T, ::Type{Val{symname}}, ::Val{isc
  end
  RT = Core.Typeof(res)
  actreg = active_reg_nothrow(RT, Val(nothing))
- if actreg == ActiveState
+ if actreg == ActiveState || (isconst && actreg == MixedState)
  if length(dptrs) == 0
  return Ref{RT}(make_zero(res))::Any
  else
@@ -659,7 +669,7 @@ function idx_jl_getfield_aug(::Val{NT}, dptr::T, ::Type{Val{symname}}, ::Val{isc
  end
  elseif actreg == MixedState
  if length(dptrs) == 0
- return Ref{RT}(res)::Any
+ return Ref{RT}(res)
  else
  fval = NT((Ref{RT}(res), (ntuple(Val(length(dptrs))) do i
  Base.@_inline_meta
@@ -668,6 +678,16 @@ function idx_jl_getfield_aug(::Val{NT}, dptr::T, ::Type{Val{symname}}, ::Val{isc
  end)...))
  return fval
  end
+ elseif isconst
+ if length(dptrs) == 0
+ return make_zero(res)::Any
+ else
+ fval = NT((res, (ntuple(Val(length(dptrs))) do i
+ Base.@_inline_meta
+ make_zero(res)
+ end)...))
+ return fval
+ end
  else
  if length(dptrs) == 0
  return res::Any
@@ -858,7 +878,7 @@ function common_jl_getfield_augfwd(offset, B, orig, gutils, normalR, shadowR, ta
  sym = emit_apply_type!(B, Base.Val, [sym])
  push!(vals, sym)
 
- push!(vals, unsafe_to_llvm(Val(is_constant_value(gutils, orig))))
+ push!(vals, unsafe_to_llvm(Val(is_constant_value(gutils, ops[2]))))
 
  for v in inps[2:end]
  push!(vals, v)
@@ -944,7 +964,7 @@ function common_jl_getfield_rev(offset, B, orig, gutils, tape)
  sym = emit_apply_type!(B, Base.Val, [sym])
  push!(vals, sym)
 
- push!(vals, unsafe_to_llvm(Val(is_constant_value(gutils, orig))))
+ push!(vals, unsafe_to_llvm(Val(is_constant_value(gutils, ops[2]))))
 
  for v in inps[2:end]
  push!(vals, v)
@@ -1037,7 +1057,7 @@ function jl_nthfield_augfwd(B, orig, gutils, normalR, shadowR, tapeR)
  sym = emit_apply_type!(B, Base.Val, [sym])
  push!(vals, sym)
 
- push!(vals, unsafe_to_llvm(Val(is_constant_value(gutils, orig))))
+ push!(vals, unsafe_to_llvm(Val(is_constant_value(gutils, ops[1]))))
 
  for v in inps[2:end]
  push!(vals, v)
@@ -1125,7 +1145,7 @@ function jl_nthfield_rev(B, orig, gutils, tape)
  sym = emit_apply_type!(B, Base.Val, [sym])
  push!(vals, sym)
 
- push!(vals, unsafe_to_llvm(Val(is_constant_value(gutils, orig))))
+ push!(vals, unsafe_to_llvm(Val(is_constant_value(gutils, ops[1]))))
 
  for v in inps[2:end]
  push!(vals, v)

test/runtests.jl

@@ -2327,7 +2327,35 @@ end
 
  adres = Enzyme.autodiff(Reverse, sf_for3, Duplicated(mt3, dmt3), Const(:x), Const(:x), Active(3.1))
  @test adres[1][4] ≈ 5050.0
+
+ mutable struct MyTypeM
+ x::Float64
+ y
+ end
+
+ @noinline function unstable_mul(x, y)
+ return (x*y)::Float64
+ end
+
+ function gf3(y, v::MyTypeM, fld::Symbol)
+ x = getfield(v, fld)
+ unstable_mul(x, y)
+ end
 
+ function gf3(y, v::MyTypeM, fld::Integer)
+ x = getfield_idx(v, fld)
+ unstable_mul(x, y)
+ end
+
+ mx = MyTypeM(3.0, 1)
+ res = Enzyme.autodiff(Reverse, gf3, Active, Active(2.7), Const(mx), Const(:x))
+ @test mx.x ≈ 3.0
+ @test res[1][1] ≈ 3.0
+
+ mx = MyTypeM(3.0, 1)
+ res = Enzyme.autodiff(Reverse, gf3, Active, Active(2.7), Const(mx), Const(0))
+ @test mx.x ≈ 3.0
+ @test res[1][1] ≈ 3.0
 end