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diff --git a/llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.h b/llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.h
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+//===-- VPlanHCFGBuilder.h --------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file defines the VPlanHCFGBuilder class which contains the public
+/// interface (buildHierarchicalCFG) to build a VPlan-based Hierarchical CFG
+/// (H-CFG) for an incoming IR.
+///
+/// A H-CFG in VPlan is a control-flow graph whose nodes are VPBasicBlocks
+/// and/or VPRegionBlocks (i.e., other H-CFGs). The outermost H-CFG of a VPlan
+/// consists of a VPRegionBlock, denoted Top Region, which encloses any other
+/// VPBlockBase in the H-CFG. This guarantees that any VPBlockBase in the H-CFG
+/// other than the Top Region will have a parent VPRegionBlock and allows us
+/// to easily add more nodes before/after the main vector loop (such as the
+/// reduction epilogue).
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_VECTORIZE_VPLAN_VPLANHCFGBUILDER_H
+#define LLVM_TRANSFORMS_VECTORIZE_VPLAN_VPLANHCFGBUILDER_H
+
+#include "VPlan.h"
+#include "VPlanDominatorTree.h"
+#include "VPlanVerifier.h"
+
+namespace llvm {
+
+class Loop;
+class VPlanTestBase;
+
+/// Main class to build the VPlan H-CFG for an incoming IR.
+class VPlanHCFGBuilder {
+  friend VPlanTestBase;
+
+private:
+  // The outermost loop of the input loop nest considered for vectorization.
+  Loop *TheLoop;
+
+  // Loop Info analysis.
+  LoopInfo *LI;
+
+  // The VPlan that will contain the H-CFG we are building.
+  VPlan &Plan;
+
+  // VPlan verifier utility.
+  VPlanVerifier Verifier;
+
+  // Dominator analysis for VPlan plain CFG to be used in the
+  // construction of the H-CFG. This analysis is no longer valid once regions
+  // are introduced.
+  VPDominatorTree VPDomTree;
+
+  /// Build plain CFG for TheLoop. Return a new VPRegionBlock (TopRegion)
+  /// enclosing the plain CFG.
+  VPRegionBlock *buildPlainCFG();
+
+public:
+  VPlanHCFGBuilder(Loop *Lp, LoopInfo *LI, VPlan &P)
+      : TheLoop(Lp), LI(LI), Plan(P) {}
+
+  /// Build H-CFG for TheLoop and update Plan accordingly.
+  void buildHierarchicalCFG();
+};
+} // namespace llvm
+
+#endif // LLVM_TRANSFORMS_VECTORIZE_VPLAN_VPLANHCFGBUILDER_H