From 2db8c15c04f2aade49636e42f0adee636afb3b73 Mon Sep 17 00:00:00 2001
From: Sai Praveen Bangaru <31557731+saipraveenb25@users.noreply.github.com>
Date: Fri, 5 Aug 2022 13:19:20 -0400
Subject: Added a new differential type system and various improvements (#2343)

* Merge slang-ir-diff-jvp.cpp

* Added support and tests for other float vector types

* Added swizzle test and code to handle it (tests failing currently)

* Fixed one test, the other is still pending

* Fixed instruction cloning logic to avoid modifying original function

* Fixed an issue with custom 'pow_jvp' and added support for vector contructor

* Minor update to comments

* Fixed support for division

* Fixed an issue with uninitialized diagnostic sink

* Moved derivative processing to after mandatory inlining.

Skip instructions that don't have side-effects and aren't used by anything.

* WIP: Handling unconditional control flow and multi-block functions

* Support for unconditional multi-block functions

* Added a dead code elimination step to the derivative pass

* Changed name of 'hasNoSideEffects()'

* Refactored variable names

* Added initial IR defs for new type system

* Added necessary logic for semantic checking

* Overhauled type system to use builtin pair types and conform to the IDifferentiable interface

* Automatically replace IRDifferentiablePairType to a custom IRStructType

* Added generics handling by expanding the conformance context functionality and allowing for type parameters

* Minor fix: early return in processPairTypes()

* Minor fixes to differentiable resolution on generic types

* Added new instructions for differential pairs. Basic tests work now.

Looking into generic types.

* Adjusted most tests to the new type system. OutType and InOutType are still not properly working.

* Updated __jvp to produce both primal and differential output

* Moved autodiff related declarations to diff.meta.slang

* Refactored variable names

* Added initial IR defs for new type system

* Added necessary logic for semantic checking

* Overhauled type system to use builtin pair types and conform to the IDifferentiable interface

* Automatically replace IRDifferentiablePairType to a custom IRStructType

* Added generics handling by expanding the conformance context functionality and allowing for type parameters

* Minor fix: early return in processPairTypes()

* Minor fixes to differentiable resolution on generic types

* Added new instructions for differential pairs. Basic tests work now.

Looking into generic types.

* Adjusted most tests to the new type system. OutType and InOutType are still not properly working.

* Updated __jvp to produce both primal and differential output

* Moved autodiff related declarations to diff.meta.slang

* Removed external changes

* Cleanup the transcription logic: each case returns a pair of insts for the primal and differential computation.
---
 source/slang/slang-ast-builder.cpp | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

(limited to 'source/slang/slang-ast-builder.cpp')

diff --git a/source/slang/slang-ast-builder.cpp b/source/slang/slang-ast-builder.cpp
index 7f23f5492..868763f76 100644
--- a/source/slang/slang-ast-builder.cpp
+++ b/source/slang/slang-ast-builder.cpp
@@ -265,7 +265,7 @@ VectorExpressionType* ASTBuilder::getVectorType(
     IntVal*  elementCount)
 {
     auto vectorGenericDecl = as<GenericDecl>(m_sharedASTBuilder->findMagicDecl("Vector"));
-        
+    
     auto vectorTypeDecl = vectorGenericDecl->inner;
 
     auto substitutions = create<GenericSubstitution>();
@@ -278,6 +278,30 @@ VectorExpressionType* ASTBuilder::getVectorType(
     return as<VectorExpressionType>(DeclRefType::create(this, declRef));
 }
 
+DifferentialPairType* ASTBuilder::getDifferentialPairType(Type* valueType, Witness* conformanceWitness)
+{
+    auto genericDecl = dynamicCast<GenericDecl>(m_sharedASTBuilder->findMagicDecl("DifferentialPairType"));
+
+    auto typeDecl = genericDecl->inner;
+
+    auto substitutions = create<GenericSubstitution>();
+    substitutions->genericDecl = genericDecl;
+    substitutions->args.add(valueType);
+    substitutions->args.add(conformanceWitness);
+
+    auto declRef = DeclRef<Decl>(typeDecl, substitutions);
+    auto rsType = DeclRefType::create(this, declRef);
+
+    return as<DifferentialPairType>(rsType);
+}
+
+DeclRef<InterfaceDecl> ASTBuilder::getDifferentiableInterface()
+{
+    DeclRef<InterfaceDecl> declRef;
+    declRef.decl = dynamicCast<InterfaceDecl>(m_sharedASTBuilder->findMagicDecl("DifferentiableType"));
+    return declRef;
+}
+
 DeclRef<Decl> ASTBuilder::getBuiltinDeclRef(const char* builtinMagicTypeName, ConstArrayView<Val*> genericArgs)
 {
     DeclRef<Decl> declRef;
-- 
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