Handle circular dependencies between structs

---------------------------

GenXIntrinsics/lib/GenXIntrinsics/GenXSingleElementVectorUtil.cpp

@@ -152,23 +152,43 @@ static Type *getTypeFreeFromSingleElementVector(Type *T) {
     if (VCINTR::VectorType::getNumElements(VecTy) == 1)
       return VecTy->getElementType();
   } else if (auto *StructTy = dyn_cast<StructType>(T)) {
+    // If there is a key for this struct type is in SEV-Free to SEV-Rich map it
+    // means that the type is already SEV-Free
+    if (SEVRichStructMap.find(StructTy) != SEVRichStructMap.end())
+      return T;
     auto It = SEVFreeStructMap.find(StructTy);
     if (It != SEVFreeStructMap.end())
       return It->second;
+    // To handle circle dependencies we create opaque struct type and add it to
+    // the map. If this struct or any nested one contains a pointer to the type
+    // we are rewriting it will be automatically changed to this incomplete type
+    // and traversing will stop
+    StructType *NewStructTy = StructType::create(T->getContext());
+    It = SEVFreeStructMap.insert(std::make_pair(StructTy, NewStructTy)).first;
     bool HasSEV = false;
     std::vector<Type *> NewElements;
     for (auto *ElemTy : StructTy->elements()) {
       Type *NewElemTy = getTypeFreeFromSingleElementVector(ElemTy);
-      if (NewElemTy != ElemTy)
-        HasSEV = true;
       NewElements.push_back(NewElemTy);
+      if (!HasSEV && NewElemTy != ElemTy) {
+        // If new type is not equal to the old one it doesn't always mean that
+        // there is a SEV element in the struct. It could be also temporary
+        // unfininished (opaque) struct type or a pointer to it
+        auto *TempTy = NewElemTy;
+        while (auto *Ptr = dyn_cast<PointerType>(TempTy))
+          TempTy = VCINTR::Type::getNonOpaquePtrEltTy(Ptr);
+        if (auto *NestedStructTy = dyn_cast<StructType>(TempTy))
+          HasSEV = !NestedStructTy->isOpaque();
+        else
+          HasSEV = true;
+      }
     }
     if (HasSEV) {
-      StructType *NewStructTy = StructType::create(NewElements);
-      SEVFreeStructMap.insert(std::make_pair(StructTy, NewStructTy));
+      NewStructTy->setBody(NewElements);
       SEVRichStructMap.insert(std::make_pair(NewStructTy, StructTy));
       return NewStructTy;
     }
+    SEVFreeStructMap.erase(It);
   }
   return T;
 }

GenXIntrinsics/test/Adaptors/sev_struct.ll

@@ -13,8 +13,8 @@ target triple = "spir64"
 
 ; CHECK: [[STRUCT1:[^ ]+]] = type { i32, <2 x i32>, [[STRUCT2:[^ ]+]] }  
 %struct.sev_test = type { <1 x i32>, <2 x i32>, %struct.sev_test_nested }
-; CHECK: [[STRUCT2]] = type { i32*, <2 x i32>* }  
-%struct.sev_test_nested = type { <1 x i32>*, <2 x i32>* }
+; CHECK: [[STRUCT2]] = type { i32*, <2 x i32>*, [[STRUCT1]]* }
+%struct.sev_test_nested = type { <1 x i32>*, <2 x i32>*, %struct.sev_test* }
 
 ; CHECK: define void @test(i32 "VCSingleElementVector"="0" %sev, i32* "VCSingleElementVector"="0" %sev_ptr)
 define void @test(<1 x i32> %sev, <1 x i32>* %sev_ptr) {
@@ -30,5 +30,9 @@ define void @test(<1 x i32> %sev, <1 x i32>* %sev_ptr) {
   %4 = getelementptr inbounds %struct.sev_test_nested, %struct.sev_test_nested* %3, i32 0, i32 0
 ; CHECK: store i32* %sev_ptr, i32** %4, align 8
   store <1 x i32>* %sev_ptr, <1 x i32>** %4, align 8
+; CHECK: %5 = getelementptr inbounds [[STRUCT2]], [[STRUCT2]]* %3, i32 0, i32 2
+  %5 = getelementptr inbounds %struct.sev_test_nested, %struct.sev_test_nested* %3, i32 0, i32 2
+; CHECK: store [[STRUCT1]]* %1, [[STRUCT1]]** %5, align 8
+  store %struct.sev_test* %1, %struct.sev_test** %5, align 8
   ret void
 }