1 //===- BlockFrequencyInfoTest.cpp - BlockFrequencyInfo unit tests ---------===//
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 #include "llvm/Analysis/BlockFrequencyInfo.h"
10 #include "llvm/Analysis/BlockFrequencyInfoImpl.h"
11 #include "llvm/Analysis/BranchProbabilityInfo.h"
12 #include "llvm/Analysis/LoopInfo.h"
13 #include "llvm/AsmParser/Parser.h"
14 #include "llvm/IR/BasicBlock.h"
15 #include "llvm/IR/Dominators.h"
16 #include "llvm/IR/Function.h"
17 #include "llvm/IR/LLVMContext.h"
18 #include "llvm/IR/Module.h"
19 #include "llvm/Support/DataTypes.h"
20 #include "llvm/Support/SourceMgr.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include "gtest/gtest.h"
23
24 namespace llvm {
25 namespace {
26
27 class BlockFrequencyInfoTest : public testing::Test {
28 protected:
29 std::unique_ptr<BranchProbabilityInfo> BPI;
30 std::unique_ptr<DominatorTree> DT;
31 std::unique_ptr<LoopInfo> LI;
32 LLVMContext C;
33
buildBFI(Function & F)34 BlockFrequencyInfo buildBFI(Function &F) {
35 DT.reset(new DominatorTree(F));
36 LI.reset(new LoopInfo(*DT));
37 BPI.reset(new BranchProbabilityInfo(F, *LI));
38 return BlockFrequencyInfo(F, *BPI, *LI);
39 }
makeLLVMModule()40 std::unique_ptr<Module> makeLLVMModule() {
41 const char *ModuleStrig = "define i32 @f(i32 %x) {\n"
42 "bb0:\n"
43 " %y1 = icmp eq i32 %x, 0 \n"
44 " br i1 %y1, label %bb1, label %bb2 \n"
45 "bb1:\n"
46 " br label %bb3\n"
47 "bb2:\n"
48 " br label %bb3\n"
49 "bb3:\n"
50 " %y2 = phi i32 [0, %bb1], [1, %bb2] \n"
51 " ret i32 %y2\n"
52 "}\n";
53 SMDiagnostic Err;
54 return parseAssemblyString(ModuleStrig, Err, C);
55 }
56 };
57
TEST_F(BlockFrequencyInfoTest,Basic)58 TEST_F(BlockFrequencyInfoTest, Basic) {
59 auto M = makeLLVMModule();
60 Function *F = M->getFunction("f");
61 F->setEntryCount(100);
62
63 BlockFrequencyInfo BFI = buildBFI(*F);
64 BasicBlock &BB0 = F->getEntryBlock();
65 BasicBlock *BB1 = BB0.getTerminator()->getSuccessor(0);
66 BasicBlock *BB2 = BB0.getTerminator()->getSuccessor(1);
67 BasicBlock *BB3 = BB1->getSingleSuccessor();
68
69 uint64_t BB0Freq = BFI.getBlockFreq(&BB0).getFrequency();
70 uint64_t BB1Freq = BFI.getBlockFreq(BB1).getFrequency();
71 uint64_t BB2Freq = BFI.getBlockFreq(BB2).getFrequency();
72 uint64_t BB3Freq = BFI.getBlockFreq(BB3).getFrequency();
73
74 EXPECT_EQ(BB0Freq, BB3Freq);
75 EXPECT_EQ(BB0Freq, BB1Freq + BB2Freq);
76 EXPECT_EQ(BB0Freq, BB3Freq);
77
78 EXPECT_EQ(*BFI.getBlockProfileCount(&BB0), UINT64_C(100));
79 EXPECT_EQ(*BFI.getBlockProfileCount(BB3), UINT64_C(100));
80 EXPECT_EQ(*BFI.getBlockProfileCount(BB1),
81 (100 * BB1Freq + BB0Freq / 2) / BB0Freq);
82 EXPECT_EQ(*BFI.getBlockProfileCount(BB2),
83 (100 * BB2Freq + BB0Freq / 2) / BB0Freq);
84
85 // Scale the frequencies of BB0, BB1 and BB2 by a factor of two.
86 SmallPtrSet<BasicBlock *, 4> BlocksToScale({BB1, BB2});
87 BFI.setBlockFreqAndScale(&BB0, BlockFrequency(BB0Freq * 2), BlocksToScale);
88 EXPECT_EQ(BFI.getBlockFreq(&BB0).getFrequency(), 2 * BB0Freq);
89 EXPECT_EQ(BFI.getBlockFreq(BB1).getFrequency(), 2 * BB1Freq);
90 EXPECT_EQ(BFI.getBlockFreq(BB2).getFrequency(), 2 * BB2Freq);
91 EXPECT_EQ(BFI.getBlockFreq(BB3).getFrequency(), BB3Freq);
92 }
93
94 static_assert(std::is_trivially_copyable_v<bfi_detail::BlockMass>,
95 "trivially copyable");
96
97 } // end anonymous namespace
98 } // end namespace llvm
99