Make `DifferentialPair` able to nest. (#2477)

1 files changed, 5 insertions, 67 deletions

diff --git a/source/slang/slang-ir-diff-jvp.cpp b/source/slang/slang-ir-diff-jvp.cpp
index 73818dbb1..3d02d4fc0 100644
--- a/source/slang/slang-ir-diff-jvp.cpp
+++ b/source/slang/slang-ir-diff-jvp.cpp
@@ -205,7 +205,7 @@ struct DifferentiableTypeConformanceContext
     {
         if (as<IRModuleInst>(inst) && differentiableInterfaceType)
         {
-            // Assume for now that IDifferentiable has exactly three fields.
+            // Assume for now that IDifferentiable has exactly four fields.
             SLANG_ASSERT(differentiableInterfaceType->getOperandCount() == 4);
             if (auto entry = as<IRInterfaceRequirementEntry>(differentiableInterfaceType->getOperand(index)))
                 return as<IRStructKey>(entry->getRequirementKey());
@@ -462,45 +462,6 @@ struct DifferentialPairTypeBuilder
         }
     }
 
-    void _createGenericDiffPairType(IRBuilder* builder)
-    {
-        // Insert directly at top level (skip any generic scopes etc.)
-        auto insertLoc = builder->getInsertLoc();
-        builder->setInsertInto(builder->getModule()->getModuleInst());
-
-        // Make a generic version of the pair struct.
-        auto irGeneric = builder->emitGeneric();
-        irGeneric->setFullType(builder->getTypeKind());
-        builder->setInsertInto(irGeneric);
-
-        generatedTypeList.add(irGeneric);
-
-        auto irBlock = builder->emitBlock();
-        builder->setInsertInto(irBlock);
-
-        auto pTypeParam = builder->emitParam(builder->getTypeType());
-        builder->addNameHintDecoration(pTypeParam, UnownedTerminatedStringSlice("pT"));
-
-        auto dTypeParam = builder->emitParam(builder->getTypeType());
-        builder->addNameHintDecoration(dTypeParam, UnownedTerminatedStringSlice("dT"));
-
-        auto irStructType = builder->createStructType();
-        builder->emitReturn(irStructType);
-
-        auto primalKey = _getOrCreatePrimalStructKey(builder);
-        builder->addNameHintDecoration(primalKey, UnownedTerminatedStringSlice("primal"));
-        builder->createStructField(irStructType, primalKey, (IRType*) pTypeParam);
-
-        auto diffKey = _getOrCreateDiffStructKey(builder);
-        builder->addNameHintDecoration(diffKey, UnownedTerminatedStringSlice("differential"));
-        builder->createStructField(irStructType, diffKey, (IRType*) dTypeParam);
-        
-        // Reset cursor when done.
-        builder->setInsertLoc(insertLoc);
-
-        this->genericDiffPairType = irGeneric;
-    }
-
     IRStructKey* _getOrCreateDiffStructKey(IRBuilder* builder)
     {
         if (!this->globalDiffKey)
@@ -535,17 +496,6 @@ struct DifferentialPairTypeBuilder
         return this->globalPrimalKey;
     }
 
-    IRInst* _getOrCreateGenericDiffPairType(IRBuilder* builder)
-    {
-        if (!this->genericDiffPairType)
-        {
-            _createGenericDiffPairType(builder);
-        }
-
-        SLANG_ASSERT(this->genericDiffPairType);
-        return this->genericDiffPairType;
-    }
-    
     IRInst* _createDiffPairType(IRBuilder* builder, IRType* origBaseType)
     {
         if (auto diffBaseType = diffConformanceContext->getDifferentialForType(builder, origBaseType))
@@ -1383,22 +1333,10 @@ struct JVPTranscriber
         }
         else
         {
-            // We special case a few non-differentiable types that sometimes appear in places
-            // where we're forced to provide a differential zero value. For instance, 
-            // float3(float, float, int) is accepted by the compiler, but is tricky in the context
-            // of differentiation since int is non-differentiable, and should be cast to float first.
-            // In the absence of such casts, this piece of code generates appropriate zero values.
-            // 
-            switch (primalType->getOp())
-            {
-                case kIROp_IntType:
-                    return builder->getIntValue(primalType, 0);
-                default:
-                    getSink()->diagnose(primalType->sourceLoc,
-                        Diagnostics::internalCompilerError,
-                        "could not generate zero value for given type");
-                    return nullptr;
-            }
+            getSink()->diagnose(primalType->sourceLoc,
+                Diagnostics::internalCompilerError,
+                "could not generate zero value for given type");
+            return nullptr;
         }
     }