Make ArrayExpressionType a DeclRefType and define its autodiff extension in stdlib. (#2615)

* Allow array parameters in forward diff.

* Use type canonicalization instead of coersion.

* Reimplement array type.

* Fix.

* Update test case.

---------

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

1 files changed, 7 insertions, 20 deletions

diff --git a/source/slang/slang-lower-to-ir.cpp b/source/slang/slang-lower-to-ir.cpp
index 605ac62db..149f5f6b9 100644
--- a/source/slang/slang-lower-to-ir.cpp
+++ b/source/slang/slang-lower-to-ir.cpp
@@ -1443,11 +1443,6 @@ struct ValLoweringVisitor : ValVisitor<ValLoweringVisitor, LoweredValInfo, Lower
         return LoweredValInfo::simple(diff);
     }
 
-    LoweredValInfo visitDifferentialBottomSubtypeWitness(DifferentialBottomSubtypeWitness*)
-    {
-        return LoweredValInfo();
-    }
-
     LoweredValInfo visitTaggedUnionSubtypeWitness(
         TaggedUnionSubtypeWitness* val)
     {
@@ -1861,10 +1856,10 @@ struct ValLoweringVisitor : ValVisitor<ValLoweringVisitor, LoweredValInfo, Lower
 
     IRType* visitArrayExpressionType(ArrayExpressionType* type)
     {
-        auto elementType = lowerType(context, type->baseType);
-        if (type->arrayLength)
+        auto elementType = lowerType(context, type->getElementType());
+        if (!type->isUnsized())
         {
-            auto elementCount = lowerSimpleVal(context, type->arrayLength);
+            auto elementCount = lowerSimpleVal(context, type->getElementCount());
             return getBuilder()->getArrayType(
                 elementType,
                 elementCount);
@@ -3390,18 +3385,10 @@ struct ExprLoweringVisitorBase : ExprVisitor<Derived, LoweredValInfo>
         }
         else if (auto arrayType = as<ArrayExpressionType>(type))
         {
-            UInt elementCount = (UInt) getIntVal(arrayType->arrayLength);
-
-            auto irDefaultElement = getSimpleVal(context, getDefaultVal(arrayType->baseType));
-
-            List<IRInst*> args;
-            for(UInt ee = 0; ee < elementCount; ++ee)
-            {
-                args.add(irDefaultElement);
-            }
+            auto irDefaultElement = getSimpleVal(context, getDefaultVal(arrayType->getElementType()));
 
             return LoweredValInfo::simple(
-                getBuilder()->emitMakeArray(irType, args.getCount(), args.getBuffer()));
+                getBuilder()->emitMakeArrayFromElement(irType, irDefaultElement));
         }
         else if (auto declRefType = as<DeclRefType>(type))
         {
@@ -3470,7 +3457,7 @@ struct ExprLoweringVisitorBase : ExprVisitor<Derived, LoweredValInfo>
         // fill in the appropriate field of the result
         if (auto arrayType = as<ArrayExpressionType>(type))
         {
-            UInt elementCount = (UInt) getIntVal(arrayType->arrayLength);
+            UInt elementCount = (UInt) getIntVal(arrayType->getElementCount());
 
             for (UInt ee = 0; ee < argCount; ++ee)
             {
@@ -3480,7 +3467,7 @@ struct ExprLoweringVisitorBase : ExprVisitor<Derived, LoweredValInfo>
             }
             if(elementCount > argCount)
             {
-                auto irDefaultValue = getSimpleVal(context, getDefaultVal(arrayType->baseType));
+                auto irDefaultValue = getSimpleVal(context, getDefaultVal(arrayType->getElementType()));
                 for(UInt ee = argCount; ee < elementCount; ++ee)
                 {
                     args.add(irDefaultValue);