Absint typeof ijl_new_structt (EnzymeAD#1206)

* Absint typeof ijl_new_structt

* add needsshadow check for jl_nthfield_rev

Author: wsmoses

src/absint.jl

@@ -146,6 +146,9 @@ function abs_typeof(arg::LLVM.Value, partial::Bool=false)::Union{Tuple{Bool, Typ
         	return absint(operands(arg)[1], partial)
         end
 
+        if nm == "jl_new_structt" || nm == "ijl_new_structt"
+            return absint(operands(arg)[1], partial)
+        end
 
         if LLVM.callconv(arg) == 37 || nm == "julia.call"
             index = 1
@@ -234,4 +237,4 @@ function abs_cstring(arg::LLVM.Value)::Tuple{Bool,String}
 	    end
 	end
 	return (false, "")
-end
+end

src/rules/typeunstablerules.jl

@@ -480,6 +480,16 @@ function jl_nthfield_rev(B, orig, gutils, tape)
         return
     end
 
+    needsShadowP = Ref{UInt8}(0)
+    needsPrimalP = Ref{UInt8}(0)
+    activep = API.EnzymeGradientUtilsGetReturnDiffeType(gutils, orig, needsPrimalP, needsShadowP, API.DEM_ReverseModePrimal)
+    needsPrimal = needsPrimalP[] != 0
+    needsShadow = needsShadowP[] != 0
+
+	if !needsShadow
+		return
+	end
+
     ops = collect(operands(orig))
     width = get_width(gutils)