Support `IDifferentiablePtrType` (#5031)

* initial diff-ref-type interface

* Initial support for `IDifferentiablePtrType`

* Fix unused vars

* More tests + fix switch case fallthrough.

* Update slang-ir-autodiff.cpp

* Update diff-ptr-type-loop.slang

* Add optimization to allow more complex pair types

* Update slang-ir-autodiff-primal-hoist.cpp

* Update diff-ptr-type-loop.slang

* Update slang-ir-autodiff-primal-hoist.cpp

* More fixes to address reviews

* Update slang-check-expr.cpp

* Optimizations + rename `differentiableRefInterfaceType` -> `differentiablePtrInterfaceType`

* Move pair logic to ir-builder, unify the type dictionaries.

---------

Co-authored-by: Yong He <yonghe@outlook.com>

1 files changed, 21 insertions, 2 deletions

diff --git a/source/slang/slang-ast-builder.cpp b/source/slang/slang-ast-builder.cpp
index 9879a4187..b66af34fa 100644
--- a/source/slang/slang-ast-builder.cpp
+++ b/source/slang/slang-ast-builder.cpp
@@ -408,18 +408,32 @@ MatrixExpressionType* ASTBuilder::getMatrixType(Type* elementType, IntVal* rowCo
 
 DifferentialPairType* ASTBuilder::getDifferentialPairType(
     Type* valueType,
-    Witness* primalIsDifferentialWitness)
+    Witness* diffTypeWitness)
 {
-    Val* args[] = { valueType, primalIsDifferentialWitness };
+    Val* args[] = { valueType, diffTypeWitness };
     return as<DifferentialPairType>(getSpecializedBuiltinType(makeArrayView(args), "DifferentialPairType"));
 }
 
+DifferentialPtrPairType* ASTBuilder::getDifferentialPtrPairType(
+    Type* valueType,
+    Witness* diffRefTypeWitness)
+{
+    Val* args[] = { valueType, diffRefTypeWitness };
+    return as<DifferentialPtrPairType>(getSpecializedBuiltinType(makeArrayView(args), "DifferentialPtrPairType"));
+}
+
 DeclRef<InterfaceDecl> ASTBuilder::getDifferentiableInterfaceDecl()
 {
     DeclRef<InterfaceDecl> declRef = DeclRef<InterfaceDecl>(getBuiltinDeclRef("DifferentiableType", nullptr));
     return declRef;
 }
 
+DeclRef<InterfaceDecl> ASTBuilder::getDifferentiableRefInterfaceDecl()
+{
+    DeclRef<InterfaceDecl> declRef = DeclRef<InterfaceDecl>(getBuiltinDeclRef("DifferentiablePtrType", nullptr));
+    return declRef;
+}
+
 bool ASTBuilder::isDifferentiableInterfaceAvailable()
 {
     return (m_sharedASTBuilder->tryFindMagicDecl("DifferentiableType") != nullptr);
@@ -459,6 +473,11 @@ Type* ASTBuilder::getDifferentiableInterfaceType()
     return DeclRefType::create(this, getDifferentiableInterfaceDecl());
 }
 
+Type* ASTBuilder::getDifferentiableRefInterfaceType()
+{
+    return DeclRefType::create(this, getDifferentiableRefInterfaceDecl());
+}
+
 DeclRef<Decl> ASTBuilder::getBuiltinDeclRef(const char* builtinMagicTypeName, Val* genericArg)
 {
     auto decl = m_sharedASTBuilder->findMagicDecl(builtinMagicTypeName);