huge refactor for high RewritePatterns usage and less ad-hoc cpp code

remove Spatial many ops in favor of tensor ops like in pim

src/PIM/Conversion/SpatialToPim/Cleanup.cpp

@@ -0,0 +1,42 @@
+#include "llvm/ADT/STLExtras.h"
+
+#include "src/Accelerators/PIM/Conversion/SpatialToPim/Cleanup.hpp"
+
+using namespace mlir;
+
+namespace onnx_mlir {
+
+LogicalResult erasePendingOps(SmallVectorImpl<Operation*>& pendingOps, IRRewriter& rewriter) {
+  while (!pendingOps.empty()) {
+    bool erasedAnyOp = false;
+    for (auto it = pendingOps.begin(); it != pendingOps.end();) {
+      Operation* opToRemove = *it;
+      if (!opToRemove->use_empty()) {
+        ++it;
+        continue;
+      }
+
+      rewriter.eraseOp(opToRemove);
+      it = pendingOps.erase(it);
+      erasedAnyOp = true;
+    }
+
+    if (erasedAnyOp)
+      continue;
+
+    for (Operation* opToRemove : pendingOps) {
+      InFlightDiagnostic diag = opToRemove->emitError("pending Spatial-to-PIM cleanup could not erase operation");
+      diag << "; op has " << llvm::range_size(opToRemove->getUsers()) << " remaining user(s)";
+      for (Operation* user : opToRemove->getUsers()) {
+        bool userPendingRemoval = llvm::is_contained(pendingOps, user);
+        opToRemove->emitRemark() << "remaining user `" << user->getName() << "`"
+                                 << (userPendingRemoval ? " is also pending removal" : " is not pending removal");
+      }
+    }
+    return failure();
+  }
+
+  return success();
+}
+
+} // namespace onnx_mlir