SIL: Generalize some explicit requiresClass() checks to use layout constraints

Author: slavapestov

lib/SIL/IR/TypeLowering.cpp

@@ -421,10 +421,6 @@ namespace {
 
     RetTy visitArchetypeType(CanArchetypeType type,
                              AbstractionPattern origType) {
-      if (type->requiresClass()) {
-        return asImpl().handleReference(type);
-      }
-
       auto LayoutInfo = type->getLayoutConstraint();
       if (LayoutInfo) {
         if (LayoutInfo->isFixedSizeTrivial()) {

lib/SILOptimizer/Transforms/CSE.cpp

@@ -428,9 +428,6 @@ bool llvm::DenseMapInfo<SimpleValue>::isEqual(SimpleValue LHS,
       return false;
 
     // ... and other constraints are equal.
-    if (LHSArchetypeTy->requiresClass() != RHSArchetypeTy->requiresClass())
-      return false;
-
     if (LHSArchetypeTy->getSuperclass().getPointer() !=
         RHSArchetypeTy->getSuperclass().getPointer())
       return false;

lib/SILOptimizer/Utils/PerformanceInlinerUtils.cpp

@@ -622,14 +622,20 @@ static bool isCallerAndCalleeLayoutConstraintsCompatible(FullApplySite AI) {
     // The generic parameter has a layout constraint.
     // Check that the substitution has the same constraint.
     auto AIReplacement = Type(Param).subst(AISubs);
-    auto AIArchetype = AIReplacement->getAs<ArchetypeType>();
-    if (!AIArchetype)
-      return false;
-    auto AILayout = AIArchetype->getLayoutConstraint();
-    if (!AILayout)
-      return false;
-    if (AILayout != Layout)
-      return false;
+
+    if (Layout->isClass()) {
+      if (!AIReplacement->satisfiesClassConstraint())
+        return false;
+    } else {
+      auto AIArchetype = AIReplacement->getAs<ArchetypeType>();
+      if (!AIArchetype)
+        return false;
+      auto AILayout = AIArchetype->getLayoutConstraint();
+      if (!AILayout)
+        return false;
+      if (AILayout != Layout)
+        return false;
+    }
   }
   return true;
 }