[llvm] [DirectX] Do not flatten GEP chains for unsupported types (PR #150484)

[Farzon Lotfi via llvm-commits]

================
@@ -263,8 +263,13 @@ bool DXILFlattenArraysVisitor::visitGetElementPtrInst(GetElementPtrInst &GEP) {
   // merge the byte offsets. Otherwise, this GEP is itself the root of a GEP
   // chain and we need to deterine the root array type
   if (auto *PtrOpGEP = dyn_cast<GEPOperator>(PtrOperand)) {
-    assert(GEPChainInfoMap.contains(PtrOpGEP) &&
-           "Expected parent GEP to be visited before this GEP");
+
+    // If the parent GEP was not processed, then we do not want to process its
----------------
farzonl wrote:

The comment makes sense as does the fix, Was wondering should we have something more explict about type checking for structs and bailing?

https://github.com/llvm/llvm-project/pull/150484