/Users/buildslave/jenkins/sharedspace/clang-stage2-coverage-R@2/llvm/lib/CodeGen/TailDuplication.cpp
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1 | | //===- TailDuplication.cpp - Duplicate blocks into predecessors' tails ----===// |
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 | | // This pass duplicates basic blocks ending in unconditional branches into |
11 | | // the tails of their predecessors, using the TailDuplicator utility class. |
12 | | // |
13 | | //===----------------------------------------------------------------------===// |
14 | | |
15 | | #include "llvm/CodeGen/MachineBranchProbabilityInfo.h" |
16 | | #include "llvm/CodeGen/MachineFunction.h" |
17 | | #include "llvm/CodeGen/MachineFunctionPass.h" |
18 | | #include "llvm/CodeGen/TailDuplicator.h" |
19 | | #include "llvm/Pass.h" |
20 | | |
21 | | using namespace llvm; |
22 | | |
23 | | #define DEBUG_TYPE "tailduplication" |
24 | | |
25 | | namespace { |
26 | | |
27 | | /// Perform tail duplication. Delegates to TailDuplicator |
28 | | class TailDuplicatePass : public MachineFunctionPass { |
29 | | TailDuplicator Duplicator; |
30 | | |
31 | | public: |
32 | | static char ID; |
33 | | |
34 | 63.7k | explicit TailDuplicatePass() : MachineFunctionPass(ID) {} |
35 | | |
36 | | bool runOnMachineFunction(MachineFunction &MF) override; |
37 | | |
38 | | void getAnalysisUsage(AnalysisUsage &AU) const override; |
39 | | }; |
40 | | |
41 | | } // end anonymous namespace |
42 | | |
43 | | char TailDuplicatePass::ID = 0; |
44 | | |
45 | | char &llvm::TailDuplicateID = TailDuplicatePass::ID; |
46 | | |
47 | | INITIALIZE_PASS(TailDuplicatePass, DEBUG_TYPE, "Tail Duplication", false, false) |
48 | | |
49 | 1.17M | bool TailDuplicatePass::runOnMachineFunction(MachineFunction &MF) { |
50 | 1.17M | if (skipFunction(*MF.getFunction())) |
51 | 88 | return false; |
52 | 1.17M | |
53 | 1.17M | auto MBPI = &getAnalysis<MachineBranchProbabilityInfo>(); |
54 | 1.17M | |
55 | 1.17M | // TODO: Querying isSSA() to determine pre-/post-regalloc is fragile, better |
56 | 1.17M | // split this into two passes instead. |
57 | 1.17M | bool PreRegAlloc = MF.getRegInfo().isSSA(); |
58 | 1.17M | Duplicator.initMF(MF, PreRegAlloc, MBPI, /* LayoutMode */ false); |
59 | 1.17M | |
60 | 1.17M | bool MadeChange = false; |
61 | 1.22M | while (Duplicator.tailDuplicateBlocks()) |
62 | 52.6k | MadeChange = true; |
63 | 1.17M | |
64 | 1.17M | return MadeChange; |
65 | 1.17M | } |
66 | | |
67 | 63.5k | void TailDuplicatePass::getAnalysisUsage(AnalysisUsage &AU) const { |
68 | 63.5k | AU.addRequired<MachineBranchProbabilityInfo>(); |
69 | 63.5k | MachineFunctionPass::getAnalysisUsage(AU); |
70 | 63.5k | } |