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llvm-mirror/unittests/Analysis/BlockFrequencyInfoTest.cpp
Easwaran Raman 89a18d93a9 [BFI] Use rounding while computing profile counts.
Summary:
Profile count of a block is computed by multiplying its block frequency
by entry count and dividing the result by entry block frequency. Do
rounded division in the last step and update test cases appropriately.

Reviewers: davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50822

llvm-svn: 339835
2018-08-16 00:26:59 +00:00

96 lines
3.5 KiB
C++

//===- 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 / 2) / BB0Freq);
EXPECT_EQ(BFI.getBlockProfileCount(BB2).getValue(),
(100 * BB2Freq + BB0Freq / 2) / 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