xref: /llvm-project/llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.h (revision 2a34ac86d3ea99f6ae8ec94935436ed0b26ddc14)
1 //===-- VPlanHCFGBuilder.h --------------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 ///
10 /// \file
11 /// This file defines the VPlanHCFGBuilder class which contains the public
12 /// interface (buildHierarchicalCFG) to build a VPlan-based Hierarchical CFG
13 /// (H-CFG) for an incoming IR.
14 ///
15 /// A H-CFG in VPlan is a control-flow graph whose nodes are VPBasicBlocks
16 /// and/or VPRegionBlocks (i.e., other H-CFGs). The outermost H-CFG of a VPlan
17 /// consists of a VPRegionBlock, denoted Top Region, which encloses any other
18 /// VPBlockBase in the H-CFG. This guarantees that any VPBlockBase in the H-CFG
19 /// other than the Top Region will have a parent VPRegionBlock and allows us
20 /// to easily add more nodes before/after the main vector loop (such as the
21 /// reduction epilogue).
22 ///
23 //===----------------------------------------------------------------------===//
24 
25 #ifndef LLVM_TRANSFORMS_VECTORIZE_VPLAN_VPLANHCFGBUILDER_H
26 #define LLVM_TRANSFORMS_VECTORIZE_VPLAN_VPLANHCFGBUILDER_H
27 
28 #include "VPlan.h"
29 #include "VPlanDominatorTree.h"
30 #include "VPlanVerifier.h"
31 
32 namespace llvm {
33 
34 class Loop;
35 class VPlanTestBase;
36 
37 /// Main class to build the VPlan H-CFG for an incoming IR.
38 class VPlanHCFGBuilder {
39   friend VPlanTestBase;
40 
41 private:
42   // The outermost loop of the input loop nest considered for vectorization.
43   Loop *TheLoop;
44 
45   // Loop Info analysis.
46   LoopInfo *LI;
47 
48   // The VPlan that will contain the H-CFG we are building.
49   VPlan &Plan;
50 
51   // VPlan verifier utility.
52   VPlanVerifier Verifier;
53 
54   // Dominator analysis for VPlan plain CFG to be used in the
55   // construction of the H-CFG. This analysis is no longer valid once regions
56   // are introduced.
57   VPDominatorTree VPDomTree;
58 
59   /// Build plain CFG for TheLoop. Return a new VPRegionBlock (TopRegion)
60   /// enclosing the plain CFG.
61   VPRegionBlock *buildPlainCFG();
62 
63 public:
64   VPlanHCFGBuilder(Loop *Lp, LoopInfo *LI, VPlan &P)
65       : TheLoop(Lp), LI(LI), Plan(P) {}
66 
67   /// Build H-CFG for TheLoop and update Plan accordingly.
68   void buildHierarchicalCFG();
69 };
70 } // namespace llvm
71 
72 #endif // LLVM_TRANSFORMS_VECTORIZE_VPLAN_VPLANHCFGBUILDER_H
73