From 6e4eae1050ab9282b460a33a013652c387c1e585 Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Thu, 23 Mar 2023 17:16:32 -0700
Subject: Hack handling of primal insts that has a function type. (#2728)

* Update diff-bwd material test

* Minor update

* Hack handling of primal insts that has a function type.

---------

Co-authored-by: winmad <winmad.wlf@gmail.com>
Co-authored-by: Yong He <yhe@nvidia.com>
---
 .../slang/slang-ir-autodiff-transcriber-base.cpp   |  7 ++++--
 source/slang/slang-ir-autodiff-transpose.h         | 27 ++++++++++++++++++++--
 2 files changed, 30 insertions(+), 4 deletions(-)

(limited to 'source')

diff --git a/source/slang/slang-ir-autodiff-transcriber-base.cpp b/source/slang/slang-ir-autodiff-transcriber-base.cpp
index 2bc67e561..552ac762c 100644
--- a/source/slang/slang-ir-autodiff-transcriber-base.cpp
+++ b/source/slang/slang-ir-autodiff-transcriber-base.cpp
@@ -1116,9 +1116,12 @@ IRInst* AutoDiffTranscriberBase::transcribe(IRBuilder* builder, IRInst* origInst
                 }
                 else
                 {
-                    if (!pair.primal->findDecoration<IRAutodiffInstDecoration>()
-                        && !as<IRConstant>(pair.differential))
+                    if (!pair.primal->findDecoration<IRAutodiffInstDecoration>())
                     {
+                        if (as<IRConstant>(pair.differential))
+                            break;
+                        if (as<IRType>(pair.differential))
+                            break;
                         auto mixedType = (IRType*)(pair.primal->getDataType());
                         builder->markInstAsMixedDifferential(pair.primal, mixedType);
                     }
diff --git a/source/slang/slang-ir-autodiff-transpose.h b/source/slang/slang-ir-autodiff-transpose.h
index 653589933..bbdb01290 100644
--- a/source/slang/slang-ir-autodiff-transpose.h
+++ b/source/slang/slang-ir-autodiff-transpose.h
@@ -950,8 +950,25 @@ struct DiffTransposePass
             // Slang doesn't support function values. So if we see a func-typed inst
             // it's proabably a reference to a function.
             // 
-            if (as<IRFuncType>(child->getDataType()))
+            switch (child->getOp())
+            {
+            /*
+               TODO: need a better way to move specialize, lookupwitness, extractExistentialType/Value/Witness
+               insts to a proper location that dominates all their use sites. Create copies of these insts
+               when necessary.
+                case kIROp_Specialize:
+                case kIROp_LookupWitness:
+                case kIROp_ExtractExistentialType:
+                case kIROp_ExtractExistentialValue:
+                case kIROp_ExtractExistentialWitnessTable:
+            */
+            case kIROp_ForwardDifferentiate:
+            case kIROp_BackwardDifferentiate:
+            case kIROp_BackwardDifferentiatePrimal:
+            case kIROp_BackwardDifferentiatePropagate:
                 typeInsts.add(child);
+                break;
+            }
         }
 
         for (auto inst : typeInsts)
@@ -959,7 +976,6 @@ struct DiffTransposePass
             inst->insertAtEnd(revBlock);
         }
 
-
         // Then, go backwards through the regular instructions, and transpose them into the new
         // rev block.
         // Note the 'reverse' traversal here.
@@ -2221,6 +2237,10 @@ struct DiffTransposePass
             case kIROp_ifElse:
             case kIROp_loop:
             case kIROp_Switch:
+            case kIROp_LookupWitness:
+            case kIROp_ExtractExistentialType:
+            case kIROp_ExtractExistentialValue:
+            case kIROp_ExtractExistentialWitnessTable:
             {
                 // Ignore. transposeBlock() should take care of adding the
                 // appropriate branch instruction.
@@ -3474,6 +3494,9 @@ struct DiffTransposePass
     List<IRUse*>                                         primalUsesToHoist;
 
     Dictionary<IRStore*, IRBlock*>                       mapStoreToDefBlock;
+
+    IRCloneEnv typeInstCloneEnv = {};
+
 };
 
 
-- 
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