Support high order diff pattern: `bwd_diff(fwd_diff(f))`. (#2695)

* Support high order diff pattern: `bwd_diff(fwd_diff(f))`.

* Fix.

---------

Co-authored-by: Yong He <yhe@nvidia.com>

1 files changed, 1 insertions, 74 deletions

diff --git a/source/slang/slang-ir-autodiff-rev.cpp b/source/slang/slang-ir-autodiff-rev.cpp
index d7cce7c53..328af4867 100644
--- a/source/slang/slang-ir-autodiff-rev.cpp
+++ b/source/slang/slang-ir-autodiff-rev.cpp
@@ -2,14 +2,12 @@
 
 #include "slang-ir-clone.h"
 #include "slang-ir-dce.h"
-#include "slang-ir-eliminate-phis.h"
 #include "slang-ir-autodiff-cfg-norm.h"
 #include "slang-ir-util.h"
 #include "slang-ir-inst-pass-base.h"
 #include "slang-ir-ssa-simplification.h"
 #include "slang-ir-autodiff-fwd.h"
 #include "slang-ir-single-return.h"
-#include "slang-ir-addr-inst-elimination.h"
 #include "slang-ir-eliminate-multilevel-break.h"
 #include "slang-ir-init-local-var.h"
 #include "slang-ir-redundancy-removal.h"
@@ -516,65 +514,6 @@ namespace Slang
         builder.emitBranch(firstBlock);
     }
 
-    void insertTempVarForMutableParams(IRModule* module, IRFunc* func)
-    {
-        IRBuilder builder(module);
-        auto firstBlock = func->getFirstBlock();
-        builder.setInsertBefore(firstBlock->getFirstOrdinaryInst());
-        
-        OrderedDictionary<IRParam*, IRVar*> mapParamToTempVar;
-        List<IRParam*> params;
-        for (auto param : firstBlock->getParams())
-        {
-            if (auto ptrType = as<IRPtrTypeBase>(param->getDataType()))
-            {
-                params.add(param);
-            }
-        }
-
-        for (auto param : params)
-        {
-            auto ptrType = as<IRPtrTypeBase>(param->getDataType());
-            auto tempVar = builder.emitVar(ptrType->getValueType());
-            param->replaceUsesWith(tempVar);
-            mapParamToTempVar[param] = tempVar;
-            if (ptrType->getOp() != kIROp_OutType)
-            {
-                builder.emitStore(tempVar, builder.emitLoad(param));
-            }
-            else
-            {
-                builder.emitStore(tempVar, builder.emitDefaultConstruct(ptrType->getValueType()));
-            }
-        }
-
-        for (auto block : func->getBlocks())
-        {
-            for (auto inst : block->getChildren())
-            {
-                if (inst->getOp() == kIROp_Return)
-                {
-                    builder.setInsertBefore(inst);
-                    for (auto& kv : mapParamToTempVar)
-                    {
-                        builder.emitStore(kv.Key, builder.emitLoad(kv.Value));
-                    }
-                }
-            }
-        }
-    }
-
-
-    struct AutoDiffAddressConversionPolicy : public AddressConversionPolicy
-    {
-        DifferentiableTypeConformanceContext* diffTypeContext;
-
-        virtual bool shouldConvertAddrInst(IRInst*) override
-        {
-            return true;
-        }
-    };
-
     SlangResult BackwardDiffTranscriberBase::prepareFuncForBackwardDiff(IRFunc* func)
     {
         DifferentiableTypeConformanceContext diffTypeContext(autoDiffSharedContext);
@@ -592,19 +531,7 @@ namespace Slang
         IRCFGNormalizationPass cfgPass = {this->getSink()};
         normalizeCFG(autoDiffSharedContext->moduleInst->getModule(), func);
 
-        insertTempVarForMutableParams(autoDiffSharedContext->moduleInst->getModule(), func);
-
-        AutoDiffAddressConversionPolicy cvtPolicty;
-        cvtPolicty.diffTypeContext = &diffTypeContext;
-        auto result = eliminateAddressInsts(&cvtPolicty, func, sink);
-
-        if (SLANG_SUCCEEDED(result))
-        {
-            disableIRValidationAtInsert();
-            simplifyFunc(func);
-            enableIRValidationAtInsert();
-        }
-        return result;
+        return SLANG_OK;
     }
 
     // Create a copy of originalFunc's forward derivative in the same generic context (if any) of