1//===-- VPlanHCFGBuilder.h --------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8///
9/// \file
10/// This file defines the VPlanHCFGBuilder class which contains the public
11/// interface (buildHierarchicalCFG) to build a VPlan-based Hierarchical CFG
12/// (H-CFG) for an incoming IR.
13///
14/// A H-CFG in VPlan is a control-flow graph whose nodes are VPBasicBlocks
15/// and/or VPRegionBlocks (i.e., other H-CFGs). The outermost H-CFG of a VPlan
16/// consists of a VPRegionBlock, denoted Top Region, which encloses any other
17/// VPBlockBase in the H-CFG. This guarantees that any VPBlockBase in the H-CFG
18/// other than the Top Region will have a parent VPRegionBlock and allows us
19/// to easily add more nodes before/after the main vector loop (such as the
20/// reduction epilogue).
21///
22//===----------------------------------------------------------------------===//
23
24#ifndef LLVM_TRANSFORMS_VECTORIZE_VPLAN_VPLANHCFGBUILDER_H
25#define LLVM_TRANSFORMS_VECTORIZE_VPLAN_VPLANHCFGBUILDER_H
26
27#include "VPlan.h"
28#include "VPlanDominatorTree.h"
29#include "VPlanVerifier.h"
30
31namespace llvm {
32
33class Loop;
34class VPlanTestBase;
35
36/// Main class to build the VPlan H-CFG for an incoming IR.
37class VPlanHCFGBuilder {
38  friend VPlanTestBase;
39
40private:
41  // The outermost loop of the input loop nest considered for vectorization.
42  Loop *TheLoop;
43
44  // Loop Info analysis.
45  LoopInfo *LI;
46
47  // The VPlan that will contain the H-CFG we are building.
48  VPlan &Plan;
49
50  // VPlan verifier utility.
51  VPlanVerifier Verifier;
52
53  // Dominator analysis for VPlan plain CFG to be used in the
54  // construction of the H-CFG. This analysis is no longer valid once regions
55  // are introduced.
56  VPDominatorTree VPDomTree;
57
58  /// Build plain CFG for TheLoop. Return a new VPRegionBlock (TopRegion)
59  /// enclosing the plain CFG.
60  VPRegionBlock *buildPlainCFG();
61
62public:
63  VPlanHCFGBuilder(Loop *Lp, LoopInfo *LI, VPlan &P)
64      : TheLoop(Lp), LI(LI), Plan(P) {}
65
66  /// Build H-CFG for TheLoop and update Plan accordingly.
67  void buildHierarchicalCFG();
68};
69} // namespace llvm
70
71#endif // LLVM_TRANSFORMS_VECTORIZE_VPLAN_VPLANHCFGBUILDER_H
72