fix bad rebase

src/activations.jl

@@ -207,7 +207,7 @@ julia> leakyrelu(-10f0, 1//20)
 -0.5f0
 ```
 """
-leakyrelu(x, a=oftf(x, 0.01)) = max(a * x, x)
+leakyrelu(x, a=oftf(x, 0.01)) = ifelse(x>0, float(x), oftf(x, a*x))  # max(a*x, x) is 3x slower
 
 """
     relu6(x) = min(max(0, x), 6)
@@ -294,7 +294,7 @@ julia> elu(-10f0, 2)
 """
 elu(x, α=1) = ifelse(x ≥ 0, float(x), α * (exp(x) - 1))
 
-deriv_elu(Ω, α=1) = ifelse(Ω ≥ 0, 1, Ω + α)
+deriv_elu(Ω, α=1) = ifelse(Ω ≥ 0, one(Ω), Ω + α)
 
 """
     gelu(x) = 0.5x * (1 + tanh(√(2/π) * (x + 0.044715x^3)))
@@ -763,14 +763,17 @@ for (f, df) in UNARY_ACTS
     @eval function rrule(::typeof(broadcasted),
                          ::typeof($f), x::Numeric)
         Ω = $f.(x)
-        function $pullback(Δ) 
-            NoTangent(), NoTangent(), @.(Δ * $df)
+        function $pullback(Δ)
+            x_thunk = InplaceableThunk(
+                dx -> @.(dx += Δ * $df),
+                @thunk @.(Δ * $df)
+            )
+            NoTangent(), NoTangent(), x_thunk
         end
         return Ω, $pullback
     end
 end
 
-
 BINARY_ACTS = [ # f, df1, df2
     (:elu, :(deriv_elu(Ω, x2)), :(NoTangent())), # TODO use real deriv instead of DNE
     ]