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 
31 namespace llvm {
32 
33 class Loop;
34 class VPlanTestBase;
35 
36 /// Main class to build the VPlan H-CFG for an incoming IR.
37 class VPlanHCFGBuilder {
38   friend VPlanTestBase;
39 
40 private:
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 This analysis is no longer valid once regions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 
62 public:
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