From d69af77971e639b47ff34bba1849efa949842a67 Mon Sep 17 00:00:00 2001
From: "William S. Moses" <gh@wsmoses.com>
Date: Sun, 24 Sep 2023 03:39:46 -0500
Subject: [PATCH] More caching

---
 ext/LinearSolveEnzymeExt.jl | 51 +++++++++++++++++++++++++++----------
 1 file changed, 37 insertions(+), 14 deletions(-)

diff --git a/ext/LinearSolveEnzymeExt.jl b/ext/LinearSolveEnzymeExt.jl
index 9db9a1770..607189e10 100644
--- a/ext/LinearSolveEnzymeExt.jl
+++ b/ext/LinearSolveEnzymeExt.jl
@@ -30,29 +30,41 @@ function EnzymeCore.EnzymeRules.augmented_primal(config, func::Const{typeof(Line
         (dval.b for dval in dres)
     end
 
-    return EnzymeCore.EnzymeRules.AugmentedReturn(res, dres, (d_A, d_b))
+
+    prob_d_A = if EnzymeRules.width(config) == 1
+        prob.dval.A
+    else
+        (dval.A for dval in prob.dval)
+    end
+    prob_d_b = if EnzymeRules.width(config) == 1
+        prob.dval.b
+    else
+        (dval.b for dval in prob.dval)
+    end
+
+    return EnzymeCore.EnzymeRules.AugmentedReturn(res, dres, (d_A, d_b, prob_d_A, prob_d_b))
 end
 
 function EnzymeCore.EnzymeRules.reverse(config, func::Const{typeof(LinearSolve.init)}, ::Type{RT}, cache, prob::EnzymeCore.Annotation{LP}, alg::Const; kwargs...) where {RT, LP <: LinearSolve.LinearProblem}
-    d_A, d_b = cache
+    d_A, d_b, prob_d_A, prob_d_b = cache
 
     if EnzymeRules.width(config) == 1
-        if d_A !== prob.dval.A
-            prob.dval.A .+= d_A
+        if d_A !== prob_d_A
+            prob_d_A .+= d_A
             d_A .= 0
         end
-        if d_b !== prob.dval.b
-            prob.dval.b .+= d_b
+        if d_b !== prob_d_b
+            prob_d_b .+= d_b
             d_b .= 0
         end
     else
         for i in 1:EnzymeRules.width(config)
-            if d_A !== prob.dval.A
-                prob.dval.A[i] .+= d_A[i]
+            if d_A !== prob_d_A[i]
+                prob_d_A[i] .+= d_A[i]
                 d_A[i] .= 0
             end
-            if d_b !== prob.dval.b
-                prob.dval.b[i] .+= d_b[i]
+            if d_b !== prob_d_b[i]
+                prob_d_b[i] .+= d_b[i]
                 d_b[i] .= 0
             end
         end
@@ -87,22 +99,33 @@ function EnzymeCore.EnzymeRules.augmented_primal(config, func::Const{typeof(Line
     resvals = if EnzymeRules.width(config) == 1
         dres.u
     else
-        (dr.u for dr in dres)
+        ntuple(Val(EnzymeRules.width(config))) do i
+            Base.@_inline_meta
+            dres[i].u
+        end
     end
 
     dAs = if EnzymeRules.width(config) == 1
         (linsolve.dval.A,)
     else
-        (dval.A for dval in linsolve.dval)
+        ntuple(Val(EnzymeRules.width(config))) do i
+            Base.@_inline_meta
+            linsolve.dval[i].A
+        end
     end
 
     dbs = if EnzymeRules.width(config) == 1
         (linsolve.dval.b,)
     else
-        (dval.b for dval in linsolve.dval)
+        ntuple(Val(EnzymeRules.width(config))) do i
+            Base.@_inline_meta
+            linsolve.dval[i].b
+        end
     end
 
-    cache = (res, resvals, deepcopy(linsolve.val), dAs, dbs)
+    cachesolve = deepcopy(linsolve.val)
+
+    cache = (copy(res.u), resvals, cachesolve, dAs, dbs)
     return EnzymeCore.EnzymeRules.AugmentedReturn(res, dres, cache)
 end