fix JuliaLang#29718, union field alignment (JuliaLang#29722)

src/cgutils.cpp

@@ -596,16 +596,9 @@ static Type *julia_struct_to_llvm(jl_value_t *jt, jl_unionall_t *ua, bool *isbox
  jlasttype = ty;
  bool isptr;
  size_t fsz = 0, al = 0;
- if (jst->layout) {
- isptr = jl_field_isptr(jst, i);
- fsz = jl_field_size(jst, i);
- al = jl_field_align(jst, i);
- }
- else { // compute what jl_compute_field_offsets would say
- isptr = !jl_islayout_inline(ty, &fsz, &al);
- if (!isptr && jl_is_uniontype(jst))
- fsz += 1;
- }
+ isptr = !jl_islayout_inline(ty, &fsz, &al);
+ if (!isptr && jl_is_uniontype(ty))
+ fsz += 1;
  Type *lty;
  if (isptr) {
  lty = T_pjlvalue;

test/core.jl

@@ -5722,6 +5722,13 @@ let x5 = UnionField5(nothing, Int8(3))
  @test hash(x5) === hash(x5copy)
 end
 
+struct UnionField6
+ alignment::Int32
+ padding::NTuple{3, UInt8}
+ #= implicit-padding::UInt8 =#
+ maybe_val::Union{UInt16, Nothing} # offset = 8, align = 8, size = 2
+end
+@test UnionField6(1,(1,1,1),2018).maybe_val == 2018
 
 # PR #23367
 struct A23367
@@ -6324,6 +6331,26 @@ let A=[0, missing], B=[missing, 0], C=Vector{Union{Int, Missing}}(undef, 6)
  @test isequal(C, [0, missing, missing, missing, 0, missing])
 end
 
+# issue #29718
+function f29718()
+ nt = NamedTuple{(:a, :b, :c, :d, :e, :f,),
+ Tuple{Union{Missing, Float64},
+ Tuple{UInt8},
+ Union{Missing, Int8},
+ Int8,
+ Tuple{UInt8,UInt8},
+ Union{Missing, Int16}}
+ }((missing,
+ (1,),
+ 1,
+ 41,
+ (1,2),
+ 1915,
+ ))
+ return Ref{Any}(nt)[].f
+end
+@test f29718() == 1915
+
 end # module UnionOptimizations
 
 # issue #6614, argument destructuring