Also add gather

src/enzyme.jl

@@ -57,16 +57,71 @@ function EnzymeCore.EnzymeRules.reverse(config, func::EnzymeCore.Const{typeof(NN
     end
 
     for (dy, dx, dw) in zip(dys, dxs, dws)
-        if !(typeof(x) <: EnzymeCore.Const) && dx !== x
-            # dx += grad wrt x
+        if !(typeof(x) <: EnzymeCore.Const) && dx !== x.val
+            # dx += grad wrt x.val
             NNlib.∇conv_data!(dx, dy, cache_w, cdims.val; alpha=eltype(dw)(1), beta=eltype(dw)(1), kwargs...)
         end
-        if !(typeof(w) <: EnzymeCore.Const) && dw !== w
-            # dw += grad wrt w
+        if !(typeof(w) <: EnzymeCore.Const) && dw !== w.val
+            # dw += grad wrt w.val
             NNlib.∇conv_filter!(dw, cache_x, dy, cdims.val; alpha=eltype(dw)(1), beta=eltype(dw)(1), kwargs...)
         end
         dy .= 0
     end
 
+    return (nothing, nothing, nothing, nothing)
+end
+
+
+function EnzymeCore.EnzymeRules.augmented_primal(config, func::EnzymeCore.Const{typeof(NNlib.gather!)}, ::Type{RT}, dst::OutType, src, idx::EnzymeCore.Const) where {OutType, RT}
+
+    @assert !(OutType <: EnzymeCore.Const)
+    if OutType <: EnzymeCore.Duplicated || OutType <: EnzymeCore.DuplicatedNoNeed
+        func.val(dst.val, src.val, idx.val)
+    end
+
+    primal = if EnzymeCore.EnzymeRules.needs_primal(config)
+        dst.val
+    else
+        nothing
+    end
+    shadow = if EnzymeCore.EnzymeRules.needs_shadow(config)
+        dst.dval
+    else
+        nothing
+    end
+
+    # Cache idx if its overwritten
+    cache_idx = ( EnzymeCore.EnzymeRules.overwritten(config)[4] && !(typeof(src) <: EnzymeCore.Const) ) ? copy(idx.val) : nothing
+
+    return EnzymeCore.EnzymeRules.AugmentedReturn(primal, shadow, cache_idx)
+end
+
+function EnzymeCore.EnzymeRules.reverse(config, func::EnzymeCore.Const{typeof(NNlib.gather!)}, ::Type{RT}, cache_idx, dst::OutType, src, idx::EnzymeCore.Const) where {OutType, RT}
+
+    # Don't cache idx if not overwritten
+    if !(typeof(src) <: EnzymeCore.Const)
+        if !EnzymeCore.EnzymeRules.overwritten(config)[4]
+            cache_idx = idx.val
+        end
+    end
+
+    ddsts = dst.dval
+    dsrcs = src.dval
+
+    if EnzymeCore.EnzymeRules.width(config) == 1
+        ddsts = (ddsts,)
+        dsrcs = (dsrcs,)
+    end
+
+    for (ddst, dsrc) in zip(ddsts, dsrcs)
+        if !(typeof(src) <: EnzymeCore.Const) && ddst !== dst.val
+            src_size = size(src.val)
+            NNlib.∇gather_src(ddst, src_size, cache_idx)
+        end
+        if !(typeof(w) <: EnzymeCore.Const) && dw !== w
+            ddst .= 0
+        end
+    end
+
     return (nothing, nothing, nothing, nothing)
 end

test/conv.jl

@@ -870,7 +870,7 @@ end
   w = rand(rng, repeat([3], spatial_rank)..., 3, 3)
   cdims = DenseConvDims(x, w)
   gradtest((x, w) -> conv(x, w, cdims), x, w)
-  gradtest((x, w) -> sum(conv(x, w, cdims)), x, w; check_enzyme_rule=true)  # https://github.com/FluxML/Flux.jl/issues/1055
+  gradtest((x, w) -> sum(conv(x, w, cdims)), x, w; check_enzyme_rrule=true)  # https://github.com/FluxML/Flux.jl/issues/1055
 
   y = conv(x, w, cdims)
   gradtest((y, w) -> ∇conv_data(y, w, cdims), y, w)

test/gather.jl

@@ -1,4 +1,6 @@
 using NNlib: gather, gather!
+import EnzymeTestUtils
+using EnzymeCore
 
 function gather_testsuite(Backend)
     device(x) = adapt(Backend(), x)
@@ -150,6 +152,17 @@ function gather_testsuite(Backend)
         Backend == CPU ?
             gradtest_fn(xs -> gather(xs, idx), src) :
             gradtest_fn((s, i) -> gather(s, i), src, idx)
+
+        if Backend == CPU
+            for Tret in (EnzymeCore.Const, EnzymeCore.Duplicated),
+                Tdst in (EnzymeCore.Duplicated, EnzymeCore.BatchDuplicated),
+                Tsrc in (EnzymeCore.Duplicated, EnzymeCore.BatchDuplicated)
+
+                EnzymeTestUtils.are_activities_compatible(Tret, Tdst, Tsrc) || continue
+
+                EnzymeTestUtils.test_reverse(fun, Tret, (dst, Tdst), (src, Tsrc), (idx, EnzymeCore.Const))
+            end
+        end
     end
 
     @testset "gather gradient for tuple index" begin

test/runtests.jl

@@ -2,6 +2,7 @@ using NNlib, Test, Statistics, Random
 using ChainRulesCore, ChainRulesTestUtils
 using Base.Broadcast: broadcasted
 import EnzymeTestUtils
+using EnzymeCore
 import FiniteDifferences
 import ForwardDiff
 import Zygote

test/test_utils.jl

@@ -22,13 +22,13 @@ function gradtest(
     end
     if check_enzyme_rrule
         if len(xs) == 2
-            for Tret in (Const, Active),
-                Tx in (Const, Duplicated, BatchDuplicated),
-                Ty in (Const, Duplicated, BatchDuplicated)
+            for Tret in (EnzymeCore.Const, EnzymeCore.Active),
+                Tx in (EnzymeCore.Const, EnzymeCore.Duplicated, EnzymeCore.BatchDuplicated),
+                Ty in (EnzymeCore.Const, EnzymeCore.Duplicated, EnzymeCore.BatchDuplicated)
 
-                are_activities_compatible(Tret, Tx, Ty) || continue
+                EnzymeTestUtils.are_activities_compatible(Tret, Tx, Ty) || continue
 
-                test_reverse(fun, Tret, (xs[1], Tx), (ys[1], Ty); atol, rtol)
+                EnzymeTestUtils.test_reverse(fun, Tret, (xs[1], Tx), (ys[1], Ty); atol, rtol)
             end
         else
             throw(AssertionError("Unsupported arg count for testing"))