[Nodecayed phis] handle repeated phi entry (#1127)

src/compiler.jl

@@ -9294,7 +9294,7 @@ function GPUCompiler.codegen(output::Symbol, job::CompilerJob{<:EnzymeTarget};
 
     if params.run_enzyme
         # Generate the adjoint
-        jlrules = String[]
+        jlrules = String["enzyme_custom"]
         for (fname, (ftyp, mi)) in foundTys
             haskey(functions(mod), fname) || continue
             push!(jlrules, fname)

src/internal_rules.jl

@@ -428,3 +428,61 @@ function EnzymeRules.reverse(config, func::Const{typeof(\)}, ::Type{RT}, cache,
 
     return (nothing,nothing)
 end
+
+# Force a rule around hvcat_fill as it is type unstable if the tuple is not of the same type (e.g., int, float, int, float)
+function EnzymeRules.augmented_primal(config, func::Const{typeof(Base.hvcat_fill!)}, ::Type{RT}, out::Annotation{AT}, inp::Annotation{BT}) where {RT, AT <: Array, BT <: Tuple}
+    primal = if EnzymeRules.needs_primal(config)
+        out.val
+    else
+        nothing
+    end
+    shadow = if EnzymeRules.needs_shadow(config)
+        out.dval
+    else
+        nothing
+    end
+    func.val(out.val, inp.val)
+
+    if EnzymeRules.width(config) == 1
+        out.dval .= 0
+    else
+        for i in 1:EnzymeRules.width(config)
+            out.dval[i] .= 0
+        end
+    end
+
+    return EnzymeRules.AugmentedReturn(primal, shadow, nothing)
+end
+
+function EnzymeRules.reverse(config, func::Const{typeof(Base.hvcat_fill!)}, ::Type{RT}, _, out::Annotation{AT}, inp::Annotation{BT}) where {RT, AT <: Array, BT <: Tuple} 
+    nr, nc = size(out.val,1), size(out.val,2)
+    for b in 1:EnzymeRules.width(config)
+        da = if EnzymeRules.width(config) == 1
+            out.dval
+        else
+            out.dval[b]
+        end
+        i = 1
+        j = 1
+        dinp = if (typeof(inp) <: Const)
+            nothing
+        else
+            ntuple(Val(length(inp.val))) do k
+                Base.@_inline_meta
+                res = da[i, j]
+                da[i, j] = 0
+                j += 1
+                if j == nc
+                    i += 1
+                    j = 1
+                end
+                if typeof(inp.val[k]) <: AbstractFloat
+                    typeof(inp.val[k])(res)
+                else
+                    typeof(inp.val[k])(0)
+                end
+            end
+        end
+        return (nothing, dinp)
+    end
+end

test/runtests.jl

@@ -2543,3 +2543,18 @@ end
     y = A \ b
     @test dA ≈ (-z * transpose(y))
 end
+
+@testset "hvcat_fill" begin
+    ar = Matrix{Float64}(undef, 2, 3)
+    dar = [1.0 2.0 3.0; 4.0 5.0 6.0]
+
+    res = Enzyme.autodiff(Reverse, Base.hvcat_fill!, Const, Duplicated(ar, dar), Active((1, 2.2, 3, 4.4, 5, 6.6)))
+
+    @test res[2][1] == 0
+    @test res[2][2] ≈ 2.0
+    @test res[2][3] ≈ 0
+    @test res[2][4] ≈ 4.0
+    @test res[2][5] ≈ 0
+    @test res[2][6] ≈ 6.0
+end
+