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Factor out UnrollAnalyzer to Analysis, and add unit tests for it. 

Summary:
Unrolling Analyzer is already pretty complicated, and it becomes harder and harder to exercise it with usual IR tests, as with them we can only check the final decision: whether the loop is unrolled or not. This change factors this framework out from LoopUnrollPass to analyses, which allows to use unit tests.
The change itself is supposed to be NFC, except adding a couple of tests.

I plan to add more tests as I add new functionality and find/fix bugs.

Reviewers: chandlerc, hfinkel, sanjoy

Subscribers: zzheng, sanjoy, llvm-commits

Differential Revision: http://reviews.llvm.org/D16623

llvm-svn: 260169
This commit is contained in:
Michael Zolotukhin 2016-02-08 23:03:59 +00:00
parent a207436b01
commit 1da4afdfc9
6 changed files with 420 additions and 239 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

93
llvm/include/llvm/Analysis/LoopUnrollAnalyzer.h Normal file
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@ -0,0 +1,93 @@
//===- llvm/Analysis/LoopUnrollAnalyzer.h - Loop Unroll Analyzer-*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements UnrolledInstAnalyzer class. It's used for predicting
// potential effects that loop unrolling might have, such as enabling constant
// propagation and other optimizations.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_LOOPUNROLLANALYZER_H
#define LLVM_ANALYSIS_LOOPUNROLLANALYZER_H
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/InstVisitor.h"
// This class is used to get an estimate of the optimization effects that we
// could get from complete loop unrolling. It comes from the fact that some
// loads might be replaced with concrete constant values and that could trigger
// a chain of instruction simplifications.
//
// E.g. we might have:
// int a[] = {0, 1, 0};
// v = 0;
// for (i = 0; i < 3; i ++)
// v += b[i]*a[i];
// If we completely unroll the loop, we would get:
// v = b[0]*a[0] + b[1]*a[1] + b[2]*a[2]
// Which then will be simplified to:
// v = b[0]* 0 + b[1]* 1 + b[2]* 0
// And finally:
// v = b[1]
namespace llvm {
class UnrolledInstAnalyzer : private InstVisitor<UnrolledInstAnalyzer, bool> {
typedef InstVisitor<UnrolledInstAnalyzer, bool> Base;
friend class InstVisitor<UnrolledInstAnalyzer, bool>;
struct SimplifiedAddress {
Value *Base = nullptr;
ConstantInt *Offset = nullptr;
};
public:
UnrolledInstAnalyzer(unsigned Iteration,
DenseMap<Value *, Constant *> &SimplifiedValues,
ScalarEvolution &SE)
: SimplifiedValues(SimplifiedValues), SE(SE) {
IterationNumber = SE.getConstant(APInt(64, Iteration));
}
// Allow access to the initial visit method.
using Base::visit;
private:
/// \brief A cache of pointer bases and constant-folded offsets corresponding
/// to GEP (or derived from GEP) instructions.
///
/// In order to find the base pointer one needs to perform non-trivial
/// traversal of the corresponding SCEV expression, so it's good to have the
/// results saved.
DenseMap<Value *, SimplifiedAddress> SimplifiedAddresses;
/// \brief SCEV expression corresponding to number of currently simulated
/// iteration.
const SCEV *IterationNumber;
/// \brief A Value->Constant map for keeping values that we managed to
/// constant-fold on the given iteration.
///
/// While we walk the loop instructions, we build up and maintain a mapping
/// of simplified values specific to this iteration. The idea is to propagate
/// any special information we have about loads that can be replaced with
/// constants after complete unrolling, and account for likely simplifications
/// post-unrolling.
DenseMap<Value *, Constant *> &SimplifiedValues;
ScalarEvolution &SE;
bool simplifyInstWithSCEV(Instruction *I);
bool visitInstruction(Instruction &I) { return simplifyInstWithSCEV(&I); }
bool visitBinaryOperator(BinaryOperator &I);
bool visitLoad(LoadInst &I);
bool visitCastInst(CastInst &I);
bool visitCmpInst(CmpInst &I);
};
}
#endif

1
llvm/lib/Analysis/CMakeLists.txt
View File

@ -39,6 +39,7 @@ add_llvm_library(LLVMAnalysis
Lint.cpp
Loads.cpp
LoopAccessAnalysis.cpp
LoopUnrollAnalyzer.cpp
LoopInfo.cpp
LoopPass.cpp
MemDepPrinter.cpp

191
llvm/lib/Analysis/LoopUnrollAnalyzer.cpp Normal file
View File

@ -0,0 +1,191 @@
//===- LoopUnrollAnalyzer.cpp - Unrolling Effect Estimation -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements UnrolledInstAnalyzer class. It's used for predicting
// potential effects that loop unrolling might have, such as enabling constant
// propagation and other optimizations.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/LoopUnrollAnalyzer.h"
#include "llvm/IR/Dominators.h"
using namespace llvm;
/// \brief Try to simplify instruction \param I using its SCEV expression.
///
/// The idea is that some AddRec expressions become constants, which then
/// could trigger folding of other instructions. However, that only happens
/// for expressions whose start value is also constant, which isn't always the
/// case. In another common and important case the start value is just some
/// address (i.e. SCEVUnknown) - in this case we compute the offset and save
/// it along with the base address instead.
bool UnrolledInstAnalyzer::simplifyInstWithSCEV(Instruction *I) {
if (!SE.isSCEVable(I->getType()))
return false;
const SCEV *S = SE.getSCEV(I);
if (auto *SC = dyn_cast<SCEVConstant>(S)) {
SimplifiedValues[I] = SC->getValue();
return true;
}
auto *AR = dyn_cast<SCEVAddRecExpr>(S);
if (!AR)
return false;
const SCEV *ValueAtIteration = AR->evaluateAtIteration(IterationNumber, SE);
// Check if the AddRec expression becomes a constant.
if (auto *SC = dyn_cast<SCEVConstant>(ValueAtIteration)) {
SimplifiedValues[I] = SC->getValue();
return true;
}
// Check if the offset from the base address becomes a constant.
auto *Base = dyn_cast<SCEVUnknown>(SE.getPointerBase(S));
if (!Base)
return false;
auto *Offset =
dyn_cast<SCEVConstant>(SE.getMinusSCEV(ValueAtIteration, Base));
if (!Offset)
return false;
SimplifiedAddress Address;
Address.Base = Base->getValue();
Address.Offset = Offset->getValue();
SimplifiedAddresses[I] = Address;
return true;
}
/// Try to simplify binary operator I.
///
/// TODO: Probably it's worth to hoist the code for estimating the
/// simplifications effects to a separate class, since we have a very similar
/// code in InlineCost already.
bool UnrolledInstAnalyzer::visitBinaryOperator(BinaryOperator &I) {
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
if (!isa<Constant>(LHS))
if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS))
LHS = SimpleLHS;
if (!isa<Constant>(RHS))
if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
RHS = SimpleRHS;
Value *SimpleV = nullptr;
const DataLayout &DL = I.getModule()->getDataLayout();
if (auto FI = dyn_cast<FPMathOperator>(&I))
SimpleV =
SimplifyFPBinOp(I.getOpcode(), LHS, RHS, FI->getFastMathFlags(), DL);
else
SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS, DL);
if (Constant *C = dyn_cast_or_null<Constant>(SimpleV))
SimplifiedValues[&I] = C;
if (SimpleV)
return true;
return Base::visitBinaryOperator(I);
}
/// Try to fold load I.
bool UnrolledInstAnalyzer::visitLoad(LoadInst &I) {
Value *AddrOp = I.getPointerOperand();
auto AddressIt = SimplifiedAddresses.find(AddrOp);
if (AddressIt == SimplifiedAddresses.end())
return false;
ConstantInt *SimplifiedAddrOp = AddressIt->second.Offset;
auto *GV = dyn_cast<GlobalVariable>(AddressIt->second.Base);
// We're only interested in loads that can be completely folded to a
// constant.
if (!GV || !GV->hasDefinitiveInitializer() || !GV->isConstant())
return false;
ConstantDataSequential *CDS =
dyn_cast<ConstantDataSequential>(GV->getInitializer());
if (!CDS)
return false;
// We might have a vector load from an array. FIXME: for now we just bail
// out in this case, but we should be able to resolve and simplify such
// loads.
if(!CDS->isElementTypeCompatible(I.getType()))
return false;
int ElemSize = CDS->getElementType()->getPrimitiveSizeInBits() / 8U;
assert(SimplifiedAddrOp->getValue().getActiveBits() < 64 &&
"Unexpectedly large index value.");
int64_t Index = SimplifiedAddrOp->getSExtValue() / ElemSize;
if (Index >= CDS->getNumElements()) {
// FIXME: For now we conservatively ignore out of bound accesses, but
// we're allowed to perform the optimization in this case.
return false;
}
Constant *CV = CDS->getElementAsConstant(Index);
assert(CV && "Constant expected.");
SimplifiedValues[&I] = CV;
return true;
}
/// Try to simplify cast instruction.
bool UnrolledInstAnalyzer::visitCastInst(CastInst &I) {
// Propagate constants through casts.
Constant *COp = dyn_cast<Constant>(I.getOperand(0));
if (!COp)
COp = SimplifiedValues.lookup(I.getOperand(0));
if (COp)
if (Constant *C =
ConstantExpr::getCast(I.getOpcode(), COp, I.getType())) {
SimplifiedValues[&I] = C;
return true;
}
return Base::visitCastInst(I);
}
/// Try to simplify cmp instruction.
bool UnrolledInstAnalyzer::visitCmpInst(CmpInst &I) {
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
// First try to handle simplified comparisons.
if (!isa<Constant>(LHS))
if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS))
LHS = SimpleLHS;
if (!isa<Constant>(RHS))
if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
RHS = SimpleRHS;
if (!isa<Constant>(LHS) && !isa<Constant>(RHS)) {
auto SimplifiedLHS = SimplifiedAddresses.find(LHS);
if (SimplifiedLHS != SimplifiedAddresses.end()) {
auto SimplifiedRHS = SimplifiedAddresses.find(RHS);
if (SimplifiedRHS != SimplifiedAddresses.end()) {
SimplifiedAddress &LHSAddr = SimplifiedLHS->second;
SimplifiedAddress &RHSAddr = SimplifiedRHS->second;
if (LHSAddr.Base == RHSAddr.Base) {
LHS = LHSAddr.Offset;
RHS = RHSAddr.Offset;
}
}
}
}
if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
if (Constant *C = ConstantExpr::getCompare(I.getPredicate(), CLHS, CRHS)) {
SimplifiedValues[&I] = C;
return true;
}
}
}
return Base::visitCmpInst(I);
}

240
llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
View File

@ -19,6 +19,7 @@
#include "llvm/Analysis/CodeMetrics.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/LoopUnrollAnalyzer.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/Analysis/TargetTransformInfo.h"
@ -168,245 +169,6 @@ static TargetTransformInfo::UnrollingPreferences gatherUnrollingPreferences(
return UP;
}
namespace {
// This class is used to get an estimate of the optimization effects that we
// could get from complete loop unrolling. It comes from the fact that some
// loads might be replaced with concrete constant values and that could trigger
// a chain of instruction simplifications.
//
// E.g. we might have:
// int a[] = {0, 1, 0};
// v = 0;
// for (i = 0; i < 3; i ++)
// v += b[i]*a[i];
// If we completely unroll the loop, we would get:
// v = b[0]*a[0] + b[1]*a[1] + b[2]*a[2]
// Which then will be simplified to:
// v = b[0]* 0 + b[1]* 1 + b[2]* 0
// And finally:
// v = b[1]
class UnrolledInstAnalyzer : private InstVisitor<UnrolledInstAnalyzer, bool> {
typedef InstVisitor<UnrolledInstAnalyzer, bool> Base;
friend class InstVisitor<UnrolledInstAnalyzer, bool>;
struct SimplifiedAddress {
Value *Base = nullptr;
ConstantInt *Offset = nullptr;
};
public:
UnrolledInstAnalyzer(unsigned Iteration,
DenseMap<Value *, Constant *> &SimplifiedValues,
ScalarEvolution &SE)
: SimplifiedValues(SimplifiedValues), SE(SE) {
IterationNumber = SE.getConstant(APInt(64, Iteration));
}
// Allow access to the initial visit method.
using Base::visit;
private:
/// \brief A cache of pointer bases and constant-folded offsets corresponding
/// to GEP (or derived from GEP) instructions.
///
/// In order to find the base pointer one needs to perform non-trivial
/// traversal of the corresponding SCEV expression, so it's good to have the
/// results saved.
DenseMap<Value *, SimplifiedAddress> SimplifiedAddresses;
/// \brief SCEV expression corresponding to number of currently simulated
/// iteration.
const SCEV *IterationNumber;
/// \brief A Value->Constant map for keeping values that we managed to
/// constant-fold on the given iteration.
///
/// While we walk the loop instructions, we build up and maintain a mapping
/// of simplified values specific to this iteration. The idea is to propagate
/// any special information we have about loads that can be replaced with
/// constants after complete unrolling, and account for likely simplifications
/// post-unrolling.
DenseMap<Value *, Constant *> &SimplifiedValues;
ScalarEvolution &SE;
/// \brief Try to simplify instruction \param I using its SCEV expression.
///
/// The idea is that some AddRec expressions become constants, which then
/// could trigger folding of other instructions. However, that only happens
/// for expressions whose start value is also constant, which isn't always the
/// case. In another common and important case the start value is just some
/// address (i.e. SCEVUnknown) - in this case we compute the offset and save
/// it along with the base address instead.
bool simplifyInstWithSCEV(Instruction *I) {
if (!SE.isSCEVable(I->getType()))
return false;
const SCEV *S = SE.getSCEV(I);
if (auto *SC = dyn_cast<SCEVConstant>(S)) {
SimplifiedValues[I] = SC->getValue();
return true;
}
auto *AR = dyn_cast<SCEVAddRecExpr>(S);
if (!AR)
return false;
const SCEV *ValueAtIteration = AR->evaluateAtIteration(IterationNumber, SE);
// Check if the AddRec expression becomes a constant.
if (auto *SC = dyn_cast<SCEVConstant>(ValueAtIteration)) {
SimplifiedValues[I] = SC->getValue();
return true;
}
// Check if the offset from the base address becomes a constant.
auto *Base = dyn_cast<SCEVUnknown>(SE.getPointerBase(S));
if (!Base)
return false;
auto *Offset =
dyn_cast<SCEVConstant>(SE.getMinusSCEV(ValueAtIteration, Base));
if (!Offset)
return false;
SimplifiedAddress Address;
Address.Base = Base->getValue();
Address.Offset = Offset->getValue();
SimplifiedAddresses[I] = Address;
return true;
}
/// Base case for the instruction visitor.
bool visitInstruction(Instruction &I) {
return simplifyInstWithSCEV(&I);
}
/// Try to simplify binary operator I.
///
/// TODO: Probably it's worth to hoist the code for estimating the
/// simplifications effects to a separate class, since we have a very similar
/// code in InlineCost already.
bool visitBinaryOperator(BinaryOperator &I) {
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
if (!isa<Constant>(LHS))
if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS))
LHS = SimpleLHS;
if (!isa<Constant>(RHS))
if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
RHS = SimpleRHS;
Value *SimpleV = nullptr;
const DataLayout &DL = I.getModule()->getDataLayout();
if (auto FI = dyn_cast<FPMathOperator>(&I))
SimpleV =
SimplifyFPBinOp(I.getOpcode(), LHS, RHS, FI->getFastMathFlags(), DL);
else
SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS, DL);
if (Constant *C = dyn_cast_or_null<Constant>(SimpleV))
SimplifiedValues[&I] = C;
if (SimpleV)
return true;
return Base::visitBinaryOperator(I);
}
/// Try to fold load I.
bool visitLoad(LoadInst &I) {
Value *AddrOp = I.getPointerOperand();
auto AddressIt = SimplifiedAddresses.find(AddrOp);
if (AddressIt == SimplifiedAddresses.end())
return false;
ConstantInt *SimplifiedAddrOp = AddressIt->second.Offset;
auto *GV = dyn_cast<GlobalVariable>(AddressIt->second.Base);
// We're only interested in loads that can be completely folded to a
// constant.
if (!GV || !GV->hasDefinitiveInitializer() || !GV->isConstant())
return false;
ConstantDataSequential *CDS =
dyn_cast<ConstantDataSequential>(GV->getInitializer());
if (!CDS)
return false;
// We might have a vector load from an array. FIXME: for now we just bail
// out in this case, but we should be able to resolve and simplify such
// loads.
if(!CDS->isElementTypeCompatible(I.getType()))
return false;
int ElemSize = CDS->getElementType()->getPrimitiveSizeInBits() / 8U;
assert(SimplifiedAddrOp->getValue().getActiveBits() < 64 &&
"Unexpectedly large index value.");
int64_t Index = SimplifiedAddrOp->getSExtValue() / ElemSize;
if (Index >= CDS->getNumElements()) {
// FIXME: For now we conservatively ignore out of bound accesses, but
// we're allowed to perform the optimization in this case.
return false;
}
Constant *CV = CDS->getElementAsConstant(Index);
assert(CV && "Constant expected.");
SimplifiedValues[&I] = CV;
return true;
}
bool visitCastInst(CastInst &I) {
// Propagate constants through casts.
Constant *COp = dyn_cast<Constant>(I.getOperand(0));
if (!COp)
COp = SimplifiedValues.lookup(I.getOperand(0));
if (COp)
if (Constant *C =
ConstantExpr::getCast(I.getOpcode(), COp, I.getType())) {
SimplifiedValues[&I] = C;
return true;
}
return Base::visitCastInst(I);
}
bool visitCmpInst(CmpInst &I) {
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
// First try to handle simplified comparisons.
if (!isa<Constant>(LHS))
if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS))
LHS = SimpleLHS;
if (!isa<Constant>(RHS))
if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
RHS = SimpleRHS;
if (!isa<Constant>(LHS) && !isa<Constant>(RHS)) {
auto SimplifiedLHS = SimplifiedAddresses.find(LHS);
if (SimplifiedLHS != SimplifiedAddresses.end()) {
auto SimplifiedRHS = SimplifiedAddresses.find(RHS);
if (SimplifiedRHS != SimplifiedAddresses.end()) {
SimplifiedAddress &LHSAddr = SimplifiedLHS->second;
SimplifiedAddress &RHSAddr = SimplifiedRHS->second;
if (LHSAddr.Base == RHSAddr.Base) {
LHS = LHSAddr.Offset;
RHS = RHSAddr.Offset;
}
}
}
}
if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
if (Constant *C = ConstantExpr::getCompare(I.getPredicate(), CLHS, CRHS)) {
SimplifiedValues[&I] = C;
return true;
}
}
}
return Base::visitCmpInst(I);
}
};
} // namespace
namespace {
struct EstimatedUnrollCost {
/// \brief The estimated cost after unrolling.

1
llvm/unittests/Analysis/CMakeLists.txt
View File

@ -13,4 +13,5 @@ add_llvm_unittest(AnalysisTests
ScalarEvolutionTest.cpp
MixedTBAATest.cpp
ValueTrackingTest.cpp
UnrollAnalyzer.cpp
)

133
llvm/unittests/Analysis/UnrollAnalyzer.cpp Normal file
View File

@ -0,0 +1,133 @@
//===- UnrollAnalyzerTest.cpp - UnrollAnalyzer 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/AsmParser/Parser.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Analysis/LoopUnrollAnalyzer.h"
#include "llvm/IR/Dominators.h"
#include "gtest/gtest.h"
using namespace llvm;
namespace llvm {
void initializeUnrollAnalyzerTestPass(PassRegistry &);
static SmallVector<DenseMap<Value *, Constant *>, 16> SimplifiedValuesVector;
static unsigned TripCount = 0;
namespace {
struct UnrollAnalyzerTest : public FunctionPass {
static char ID;
bool runOnFunction(Function &F) override {
LoopInfo *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
ScalarEvolution *SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
Function::iterator FI = F.begin();
FI++; // First basic block is entry - skip it.
BasicBlock *Header = &*FI++;
Loop *L = LI->getLoopFor(Header);
SimplifiedValuesVector.clear();
TripCount = SE->getSmallConstantTripCount(L, Header);
for (unsigned Iteration = 0; Iteration < TripCount; Iteration++) {
DenseMap<Value *, Constant *> SimplifiedValues;
UnrolledInstAnalyzer Analyzer(Iteration, SimplifiedValues, *SE);
for (Instruction &I : *Header)
Analyzer.visit(I);
SimplifiedValuesVector.push_back(SimplifiedValues);
}
return false;
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<LoopInfoWrapperPass>();
AU.addRequired<ScalarEvolutionWrapperPass>();
AU.setPreservesAll();
}
UnrollAnalyzerTest() : FunctionPass(ID) {
initializeUnrollAnalyzerTestPass(*PassRegistry::getPassRegistry());
}
};
}
char UnrollAnalyzerTest::ID = 0;
std::unique_ptr<Module> makeLLVMModule(UnrollAnalyzerTest *P,
const char *ModuleStr) {
LLVMContext &C = getGlobalContext();
SMDiagnostic Err;
return parseAssemblyString(ModuleStr, Err, C);
}
TEST(UnrollAnalyzerTest, BasicSimplifications) {
const char *ModuleStr =
"target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
"define i64 @propagate_loop_phis() {\n"
"entry:\n"
" br label %loop\n"
"loop:\n"
" %iv = phi i64 [ 0, %entry ], [ %inc, %loop ]\n"
" %x0 = phi i64 [ 0, %entry ], [ %x2, %loop ]\n"
" %x1 = or i64 %x0, 1\n"
" %x2 = or i64 %x1, 2\n"
" %inc = add nuw nsw i64 %iv, 1\n"
" %cond = icmp sge i64 %inc, 8\n"
" br i1 %cond, label %loop.end, label %loop\n"
"loop.end:\n"
" %x.lcssa = phi i64 [ %x2, %loop ]\n"
" ret i64 %x.lcssa\n"
"}\n";
UnrollAnalyzerTest *P = new UnrollAnalyzerTest();
std::unique_ptr<Module> M = makeLLVMModule(P, ModuleStr);
legacy::PassManager Passes;
Passes.add(P);
Passes.run(*M);
// Perform checks
Module::iterator MI = M->begin();
Function *F = &*MI++;
Function::iterator FI = F->begin();
FI++; // First basic block is entry - skip it.
BasicBlock *Header = &*FI++;
BasicBlock::iterator BBI = Header->begin();
std::advance(BBI, 4);
Instruction *Y1 = &*BBI++;
Instruction *Y2 = &*BBI++;
// Check simplification expected on the 1st iteration.
// Check that "%inc = add nuw nsw i64 %iv, 1" is simplified to 1
auto I1 = SimplifiedValuesVector[0].find(Y1);
EXPECT_TRUE(I1 != SimplifiedValuesVector[0].end());
EXPECT_EQ(dyn_cast<ConstantInt>((*I1).second)->getZExtValue(), 1U);
// Check that "%cond = icmp sge i64 %inc, 10" is simplified to false
auto I2 = SimplifiedValuesVector[0].find(Y2);
EXPECT_TRUE(I2 != SimplifiedValuesVector[0].end());
EXPECT_FALSE(dyn_cast<ConstantInt>((*I2).second)->getZExtValue());
// Check simplification expected on the last iteration.
// Check that "%inc = add nuw nsw i64 %iv, 1" is simplified to 8
I1 = SimplifiedValuesVector[TripCount - 1].find(Y1);
EXPECT_TRUE(I1 != SimplifiedValuesVector[TripCount - 1].end());
EXPECT_EQ(dyn_cast<ConstantInt>((*I1).second)->getZExtValue(), TripCount);
// Check that "%cond = icmp sge i64 %inc, 10" is simplified to false
I2 = SimplifiedValuesVector[TripCount - 1].find(Y2);
EXPECT_TRUE(I2 != SimplifiedValuesVector[TripCount - 1].end());
EXPECT_TRUE(dyn_cast<ConstantInt>((*I2).second)->getZExtValue());
}
} // end namespace llvm
INITIALIZE_PASS_BEGIN(UnrollAnalyzerTest, "unrollanalyzertestpass",
"unrollanalyzertestpass", false, false)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
INITIALIZE_PASS_END(UnrollAnalyzerTest, "unrollanalyzertestpass",
"unrollanalyzertestpass", false, false)