[Mlir-commits] [mlir] [mlir][reducer] Add eraseAllOpsInRegion function to reduction-tree pass (PR #185892)

[Jeremy Kun]

================
@@ -145,19 +145,59 @@ static LogicalResult findOptimal(ModuleOp module, Region &region,
   return success();
 }
 
+/// This function attempts to erase all operations within the region currently
+/// being processed.
+static LogicalResult eraseAllOpsInRegion(ModuleOp module, Region &region,
+                                         const Tester &test) {
+  std::pair<Tester::Interestingness, size_t> initStatus =
+      test.isInteresting(module);
+
+  // While exploring the reduction tree, we always branch from an interesting
+  // node. Thus the root node must be interesting.
+  if (initStatus.first != Tester::Interestingness::True)
+    return module.emitWarning() << "uninterested module will not be reduced";
+  llvm::SpecificBumpPtrAllocator<ReductionNode> allocator;
+
+  // Setting the ranges to {{0, 0}} will result in the deletion of all ops
+  // within the region.
+  std::vector<ReductionNode::Range> ranges{{0, 0}};
+  ReductionNode *root = allocator.Allocate();
+  new (root) ReductionNode(nullptr, ranges, allocator);
----------------
j2kun wrote:

Forgive me, I'm not familiar with the memory management style happening here, but if this new reduction node is only live for the scope of this function, why not allocate it on the stack instead of using `new`?

https://github.com/llvm/llvm-project/pull/185892