llvm-project/llvm/unittests/Analysis/BlockFrequencyInfoTest.cpp

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//===- BlockFrequencyInfoTest.cpp - BlockFrequencyInfo unit tests ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/raw_ostream.h"
#include "gtest/gtest.h"
namespace llvm {
namespace {
class BlockFrequencyInfoTest : public testing::Test {
protected:
std::unique_ptr<BranchProbabilityInfo> BPI;
std::unique_ptr<DominatorTree> DT;
std::unique_ptr<LoopInfo> LI;
LLVMContext C;
BlockFrequencyInfo buildBFI(Function &F) {
DT.reset(new DominatorTree(F));
LI.reset(new LoopInfo(*DT));
BPI.reset(new BranchProbabilityInfo(F, *LI));
return BlockFrequencyInfo(F, *BPI, *LI);
}
std::unique_ptr<Module> makeLLVMModule() {
const char *ModuleStrig = "define i32 @f(i32 %x) {\n"
"bb0:\n"
" %y1 = icmp eq i32 %x, 0 \n"
" br i1 %y1, label %bb1, label %bb2 \n"
"bb1:\n"
" br label %bb3\n"
"bb2:\n"
" br label %bb3\n"
"bb3:\n"
" %y2 = phi i32 [0, %bb1], [1, %bb2] \n"
" ret i32 %y2\n"
"}\n";
SMDiagnostic Err;
return parseAssemblyString(ModuleStrig, Err, C);
}
};
TEST_F(BlockFrequencyInfoTest, Basic) {
auto M = makeLLVMModule();
Function *F = M->getFunction("f");
F->setEntryCount(100);
BlockFrequencyInfo BFI = buildBFI(*F);
BasicBlock &BB0 = F->getEntryBlock();
BasicBlock *BB1 = BB0.getTerminator()->getSuccessor(0);
BasicBlock *BB2 = BB0.getTerminator()->getSuccessor(1);
BasicBlock *BB3 = BB1->getSingleSuccessor();
uint64_t BB0Freq = BFI.getBlockFreq(&BB0).getFrequency();
uint64_t BB1Freq = BFI.getBlockFreq(BB1).getFrequency();
uint64_t BB2Freq = BFI.getBlockFreq(BB2).getFrequency();
uint64_t BB3Freq = BFI.getBlockFreq(BB3).getFrequency();
EXPECT_EQ(BB0Freq, BB3Freq);
EXPECT_EQ(BB0Freq, BB1Freq + BB2Freq);
EXPECT_EQ(BB0Freq, BB3Freq);
EXPECT_EQ(BFI.getBlockProfileCount(&BB0).getValue(), UINT64_C(100));
EXPECT_EQ(BFI.getBlockProfileCount(BB3).getValue(), UINT64_C(100));
EXPECT_EQ(BFI.getBlockProfileCount(BB1).getValue(), 100 * BB1Freq / BB0Freq);
EXPECT_EQ(BFI.getBlockProfileCount(BB2).getValue(), 100 * BB2Freq / BB0Freq);
// Scale the frequencies of BB0, BB1 and BB2 by a factor of two.
SmallPtrSet<BasicBlock *, 4> BlocksToScale({BB1, BB2});
BFI.setBlockFreqAndScale(&BB0, BB0Freq * 2, BlocksToScale);
EXPECT_EQ(BFI.getBlockFreq(&BB0).getFrequency(), 2 * BB0Freq);
EXPECT_EQ(BFI.getBlockFreq(BB1).getFrequency(), 2 * BB1Freq);
EXPECT_EQ(BFI.getBlockFreq(BB2).getFrequency(), 2 * BB2Freq);
EXPECT_EQ(BFI.getBlockFreq(BB3).getFrequency(), BB3Freq);
}
} // end anonymous namespace
} // end namespace llvm