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

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//===- MemorySSA.cpp - Unit tests for MemorySSA ---------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/MemorySSA.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/BasicAliasAnalysis.h"
#include "llvm/Analysis/MemorySSAUpdater.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/Support/SourceMgr.h"
#include "gtest/gtest.h"
using namespace llvm;
const static char DLString[] = "e-i64:64-f80:128-n8:16:32:64-S128";
/// There's a lot of common setup between these tests. This fixture helps reduce
/// that. Tests should mock up a function, store it in F, and then call
/// setupAnalyses().
class MemorySSATest : public testing::Test {
protected:
// N.B. Many of these members depend on each other (e.g. the Module depends on
// the Context, etc.). So, order matters here (and in TestAnalyses).
LLVMContext C;
Module M;
IRBuilder<> B;
DataLayout DL;
TargetLibraryInfoImpl TLII;
TargetLibraryInfo TLI;
Function *F;
// Things that we need to build after the function is created.
struct TestAnalyses {
DominatorTree DT;
AssumptionCache AC;
AAResults AA;
BasicAAResult BAA;
// We need to defer MSSA construction until AA is *entirely* set up, which
// requires calling addAAResult. Hence, we just use a pointer here.
std::unique_ptr<MemorySSA> MSSA;
MemorySSAWalker *Walker;
TestAnalyses(MemorySSATest &Test)
: DT(*Test.F), AC(*Test.F), AA(Test.TLI),
BAA(Test.DL, *Test.F, Test.TLI, AC, &DT) {
AA.addAAResult(BAA);
MSSA = std::make_unique<MemorySSA>(*Test.F, &AA, &DT);
Walker = MSSA->getWalker();
}
};
std::unique_ptr<TestAnalyses> Analyses;
void setupAnalyses() {
assert(F);
Analyses.reset(new TestAnalyses(*this));
}
public:
MemorySSATest()
: M("MemorySSATest", C), B(C), DL(DLString), TLI(TLII), F(nullptr) {}
};
TEST_F(MemorySSATest, CreateALoad) {
// We create a diamond where there is a store on one side, and then after
// building MemorySSA, create a load after the merge point, and use it to test
// updating by creating an access for the load.
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry(BasicBlock::Create(C, "", F));
BasicBlock *Left(BasicBlock::Create(C, "", F));
BasicBlock *Right(BasicBlock::Create(C, "", F));
BasicBlock *Merge(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
B.CreateCondBr(B.getTrue(), Left, Right);
B.SetInsertPoint(Left);
Argument *PointerArg = &*F->arg_begin();
B.CreateStore(B.getInt8(16), PointerArg);
BranchInst::Create(Merge, Left);
BranchInst::Create(Merge, Right);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAUpdater Updater(&MSSA);
// Add the load
B.SetInsertPoint(Merge);
LoadInst *LoadInst = B.CreateLoad(B.getInt8Ty(), PointerArg);
// MemoryPHI should already exist.
MemoryPhi *MP = MSSA.getMemoryAccess(Merge);
EXPECT_NE(MP, nullptr);
// Create the load memory acccess
MemoryUse *LoadAccess = cast<MemoryUse>(Updater.createMemoryAccessInBB(
LoadInst, MP, Merge, MemorySSA::Beginning));
MemoryAccess *DefiningAccess = LoadAccess->getDefiningAccess();
EXPECT_TRUE(isa<MemoryPhi>(DefiningAccess));
MSSA.verifyMemorySSA();
}
TEST_F(MemorySSATest, CreateLoadsAndStoreUpdater) {
// We create a diamond, then build memoryssa with no memory accesses, and
// incrementally update it by inserting a store in the, entry, a load in the
// merge point, then a store in the branch, another load in the merge point,
// and then a store in the entry.
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry(BasicBlock::Create(C, "", F));
BasicBlock *Left(BasicBlock::Create(C, "", F));
BasicBlock *Right(BasicBlock::Create(C, "", F));
BasicBlock *Merge(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
B.CreateCondBr(B.getTrue(), Left, Right);
B.SetInsertPoint(Left, Left->begin());
Argument *PointerArg = &*F->arg_begin();
B.SetInsertPoint(Left);
B.CreateBr(Merge);
B.SetInsertPoint(Right);
B.CreateBr(Merge);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAUpdater Updater(&MSSA);
// Add the store
B.SetInsertPoint(Entry, Entry->begin());
StoreInst *EntryStore = B.CreateStore(B.getInt8(16), PointerArg);
MemoryAccess *EntryStoreAccess = Updater.createMemoryAccessInBB(
EntryStore, nullptr, Entry, MemorySSA::Beginning);
Updater.insertDef(cast<MemoryDef>(EntryStoreAccess));
// Add the load
B.SetInsertPoint(Merge, Merge->begin());
LoadInst *FirstLoad = B.CreateLoad(B.getInt8Ty(), PointerArg);
// MemoryPHI should not already exist.
MemoryPhi *MP = MSSA.getMemoryAccess(Merge);
EXPECT_EQ(MP, nullptr);
// Create the load memory access
MemoryUse *FirstLoadAccess = cast<MemoryUse>(Updater.createMemoryAccessInBB(
FirstLoad, nullptr, Merge, MemorySSA::Beginning));
Updater.insertUse(FirstLoadAccess);
// Should just have a load using the entry access, because it should discover
// the phi is trivial
EXPECT_EQ(FirstLoadAccess->getDefiningAccess(), EntryStoreAccess);
// Create a store on the left
// Add the store
B.SetInsertPoint(Left, Left->begin());
StoreInst *LeftStore = B.CreateStore(B.getInt8(16), PointerArg);
MemoryAccess *LeftStoreAccess = Updater.createMemoryAccessInBB(
LeftStore, nullptr, Left, MemorySSA::Beginning);
Updater.insertDef(cast<MemoryDef>(LeftStoreAccess), false);
// MemoryPHI should exist after adding LeftStore.
MP = MSSA.getMemoryAccess(Merge);
EXPECT_NE(MP, nullptr);
// Add the second load
B.SetInsertPoint(Merge, Merge->begin());
LoadInst *SecondLoad = B.CreateLoad(B.getInt8Ty(), PointerArg);
// Create the load memory access
MemoryUse *SecondLoadAccess = cast<MemoryUse>(Updater.createMemoryAccessInBB(
SecondLoad, nullptr, Merge, MemorySSA::Beginning));
Updater.insertUse(SecondLoadAccess);
// Now the load should be a phi of the entry store and the left store
MemoryPhi *MergePhi =
dyn_cast<MemoryPhi>(SecondLoadAccess->getDefiningAccess());
EXPECT_NE(MergePhi, nullptr);
EXPECT_EQ(MergePhi->getIncomingValue(0), EntryStoreAccess);
EXPECT_EQ(MergePhi->getIncomingValue(1), LeftStoreAccess);
// Now create a store below the existing one in the entry
B.SetInsertPoint(Entry, --Entry->end());
StoreInst *SecondEntryStore = B.CreateStore(B.getInt8(16), PointerArg);
MemoryAccess *SecondEntryStoreAccess = Updater.createMemoryAccessInBB(
SecondEntryStore, nullptr, Entry, MemorySSA::End);
// Insert it twice just to test renaming
Updater.insertDef(cast<MemoryDef>(SecondEntryStoreAccess), false);
EXPECT_NE(FirstLoadAccess->getDefiningAccess(), MergePhi);
Updater.insertDef(cast<MemoryDef>(SecondEntryStoreAccess), true);
EXPECT_EQ(FirstLoadAccess->getDefiningAccess(), MergePhi);
// and make sure the phi below it got updated, despite being blocks away
MergePhi = dyn_cast<MemoryPhi>(SecondLoadAccess->getDefiningAccess());
EXPECT_NE(MergePhi, nullptr);
EXPECT_EQ(MergePhi->getIncomingValue(0), SecondEntryStoreAccess);
EXPECT_EQ(MergePhi->getIncomingValue(1), LeftStoreAccess);
MSSA.verifyMemorySSA();
}
TEST_F(MemorySSATest, CreateALoadUpdater) {
// We create a diamond, then build memoryssa with no memory accesses, and
// incrementally update it by inserting a store in one of the branches, and a
// load in the merge point
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry(BasicBlock::Create(C, "", F));
BasicBlock *Left(BasicBlock::Create(C, "", F));
BasicBlock *Right(BasicBlock::Create(C, "", F));
BasicBlock *Merge(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
B.CreateCondBr(B.getTrue(), Left, Right);
B.SetInsertPoint(Left, Left->begin());
Argument *PointerArg = &*F->arg_begin();
B.SetInsertPoint(Left);
B.CreateBr(Merge);
B.SetInsertPoint(Right);
B.CreateBr(Merge);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAUpdater Updater(&MSSA);
B.SetInsertPoint(Left, Left->begin());
// Add the store
StoreInst *SI = B.CreateStore(B.getInt8(16), PointerArg);
MemoryAccess *StoreAccess =
Updater.createMemoryAccessInBB(SI, nullptr, Left, MemorySSA::Beginning);
Updater.insertDef(cast<MemoryDef>(StoreAccess));
// MemoryPHI should be created when inserting the def
MemoryPhi *MP = MSSA.getMemoryAccess(Merge);
EXPECT_NE(MP, nullptr);
// Add the load
B.SetInsertPoint(Merge, Merge->begin());
LoadInst *LoadInst = B.CreateLoad(B.getInt8Ty(), PointerArg);
// Create the load memory acccess
MemoryUse *LoadAccess = cast<MemoryUse>(Updater.createMemoryAccessInBB(
LoadInst, nullptr, Merge, MemorySSA::Beginning));
Updater.insertUse(LoadAccess);
MemoryAccess *DefiningAccess = LoadAccess->getDefiningAccess();
EXPECT_TRUE(isa<MemoryPhi>(DefiningAccess));
MSSA.verifyMemorySSA();
}
TEST_F(MemorySSATest, SinkLoad) {
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry(BasicBlock::Create(C, "", F));
BasicBlock *Left(BasicBlock::Create(C, "", F));
BasicBlock *Right(BasicBlock::Create(C, "", F));
BasicBlock *Merge(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
B.CreateCondBr(B.getTrue(), Left, Right);
B.SetInsertPoint(Left, Left->begin());
Argument *PointerArg = &*F->arg_begin();
B.SetInsertPoint(Left);
B.CreateBr(Merge);
B.SetInsertPoint(Right);
B.CreateBr(Merge);
// Load in left block
B.SetInsertPoint(Left, Left->begin());
LoadInst *LoadInst1 = B.CreateLoad(B.getInt8Ty(), PointerArg);
// Store in merge block
B.SetInsertPoint(Merge, Merge->begin());
B.CreateStore(B.getInt8(16), PointerArg);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAUpdater Updater(&MSSA);
// Mimic sinking of a load:
// - clone load
// - insert in "exit" block
// - insert in mssa
// - remove from original block
LoadInst *LoadInstClone = cast<LoadInst>(LoadInst1->clone());
Merge->getInstList().insert(Merge->begin(), LoadInstClone);
MemoryAccess * NewLoadAccess =
Updater.createMemoryAccessInBB(LoadInstClone, nullptr,
LoadInstClone->getParent(),
MemorySSA::Beginning);
Updater.insertUse(cast<MemoryUse>(NewLoadAccess));
MSSA.verifyMemorySSA();
Updater.removeMemoryAccess(MSSA.getMemoryAccess(LoadInst1));
MSSA.verifyMemorySSA();
}
TEST_F(MemorySSATest, MoveAStore) {
// We create a diamond where there is a in the entry, a store on one side, and
// a load at the end. After building MemorySSA, we test updating by moving
// the store from the side block to the entry block. This destroys the old
// access.
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry(BasicBlock::Create(C, "", F));
BasicBlock *Left(BasicBlock::Create(C, "", F));
BasicBlock *Right(BasicBlock::Create(C, "", F));
BasicBlock *Merge(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
Argument *PointerArg = &*F->arg_begin();
StoreInst *EntryStore = B.CreateStore(B.getInt8(16), PointerArg);
B.CreateCondBr(B.getTrue(), Left, Right);
B.SetInsertPoint(Left);
StoreInst *SideStore = B.CreateStore(B.getInt8(16), PointerArg);
BranchInst::Create(Merge, Left);
BranchInst::Create(Merge, Right);
B.SetInsertPoint(Merge);
B.CreateLoad(B.getInt8Ty(), PointerArg);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAUpdater Updater(&MSSA);
// Move the store
SideStore->moveBefore(Entry->getTerminator());
MemoryAccess *EntryStoreAccess = MSSA.getMemoryAccess(EntryStore);
MemoryAccess *SideStoreAccess = MSSA.getMemoryAccess(SideStore);
MemoryAccess *NewStoreAccess = Updater.createMemoryAccessAfter(
SideStore, EntryStoreAccess, EntryStoreAccess);
EntryStoreAccess->replaceAllUsesWith(NewStoreAccess);
Updater.removeMemoryAccess(SideStoreAccess);
MSSA.verifyMemorySSA();
}
TEST_F(MemorySSATest, MoveAStoreUpdater) {
// We create a diamond where there is a in the entry, a store on one side, and
// a load at the end. After building MemorySSA, we test updating by moving
// the store from the side block to the entry block. This destroys the old
// access.
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry(BasicBlock::Create(C, "", F));
BasicBlock *Left(BasicBlock::Create(C, "", F));
BasicBlock *Right(BasicBlock::Create(C, "", F));
BasicBlock *Merge(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
Argument *PointerArg = &*F->arg_begin();
StoreInst *EntryStore = B.CreateStore(B.getInt8(16), PointerArg);
B.CreateCondBr(B.getTrue(), Left, Right);
B.SetInsertPoint(Left);
auto *SideStore = B.CreateStore(B.getInt8(16), PointerArg);
BranchInst::Create(Merge, Left);
BranchInst::Create(Merge, Right);
B.SetInsertPoint(Merge);
auto *MergeLoad = B.CreateLoad(B.getInt8Ty(), PointerArg);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAUpdater Updater(&MSSA);
// Move the store
SideStore->moveBefore(Entry->getTerminator());
auto *EntryStoreAccess = MSSA.getMemoryAccess(EntryStore);
auto *SideStoreAccess = MSSA.getMemoryAccess(SideStore);
auto *NewStoreAccess = Updater.createMemoryAccessAfter(
SideStore, EntryStoreAccess, EntryStoreAccess);
// Before, the load will point to a phi of the EntryStore and SideStore.
auto *LoadAccess = cast<MemoryUse>(MSSA.getMemoryAccess(MergeLoad));
EXPECT_TRUE(isa<MemoryPhi>(LoadAccess->getDefiningAccess()));
MemoryPhi *MergePhi = cast<MemoryPhi>(LoadAccess->getDefiningAccess());
EXPECT_EQ(MergePhi->getIncomingValue(1), EntryStoreAccess);
EXPECT_EQ(MergePhi->getIncomingValue(0), SideStoreAccess);
Updater.removeMemoryAccess(SideStoreAccess);
Updater.insertDef(cast<MemoryDef>(NewStoreAccess));
// After it's a phi of the new side store access.
EXPECT_EQ(MergePhi->getIncomingValue(0), NewStoreAccess);
EXPECT_EQ(MergePhi->getIncomingValue(1), NewStoreAccess);
MSSA.verifyMemorySSA();
}
TEST_F(MemorySSATest, MoveAStoreUpdaterMove) {
// We create a diamond where there is a in the entry, a store on one side, and
// a load at the end. After building MemorySSA, we test updating by moving
// the store from the side block to the entry block. This does not destroy
// the old access.
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry(BasicBlock::Create(C, "", F));
BasicBlock *Left(BasicBlock::Create(C, "", F));
BasicBlock *Right(BasicBlock::Create(C, "", F));
BasicBlock *Merge(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
Argument *PointerArg = &*F->arg_begin();
StoreInst *EntryStore = B.CreateStore(B.getInt8(16), PointerArg);
B.CreateCondBr(B.getTrue(), Left, Right);
B.SetInsertPoint(Left);
auto *SideStore = B.CreateStore(B.getInt8(16), PointerArg);
BranchInst::Create(Merge, Left);
BranchInst::Create(Merge, Right);
B.SetInsertPoint(Merge);
auto *MergeLoad = B.CreateLoad(B.getInt8Ty(), PointerArg);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAUpdater Updater(&MSSA);
// Move the store
auto *EntryStoreAccess = MSSA.getMemoryAccess(EntryStore);
auto *SideStoreAccess = MSSA.getMemoryAccess(SideStore);
// Before, the load will point to a phi of the EntryStore and SideStore.
auto *LoadAccess = cast<MemoryUse>(MSSA.getMemoryAccess(MergeLoad));
EXPECT_TRUE(isa<MemoryPhi>(LoadAccess->getDefiningAccess()));
MemoryPhi *MergePhi = cast<MemoryPhi>(LoadAccess->getDefiningAccess());
EXPECT_EQ(MergePhi->getIncomingValue(1), EntryStoreAccess);
EXPECT_EQ(MergePhi->getIncomingValue(0), SideStoreAccess);
SideStore->moveBefore(*EntryStore->getParent(), ++EntryStore->getIterator());
Updater.moveAfter(SideStoreAccess, EntryStoreAccess);
// After, it's a phi of the side store.
EXPECT_EQ(MergePhi->getIncomingValue(0), SideStoreAccess);
EXPECT_EQ(MergePhi->getIncomingValue(1), SideStoreAccess);
MSSA.verifyMemorySSA();
}
TEST_F(MemorySSATest, MoveAStoreAllAround) {
// We create a diamond where there is a in the entry, a store on one side, and
// a load at the end. After building MemorySSA, we test updating by moving
// the store from the side block to the entry block, then to the other side
// block, then to before the load. This does not destroy the old access.
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry(BasicBlock::Create(C, "", F));
BasicBlock *Left(BasicBlock::Create(C, "", F));
BasicBlock *Right(BasicBlock::Create(C, "", F));
BasicBlock *Merge(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
Argument *PointerArg = &*F->arg_begin();
StoreInst *EntryStore = B.CreateStore(B.getInt8(16), PointerArg);
B.CreateCondBr(B.getTrue(), Left, Right);
B.SetInsertPoint(Left);
auto *SideStore = B.CreateStore(B.getInt8(16), PointerArg);
BranchInst::Create(Merge, Left);
BranchInst::Create(Merge, Right);
B.SetInsertPoint(Merge);
auto *MergeLoad = B.CreateLoad(B.getInt8Ty(), PointerArg);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAUpdater Updater(&MSSA);
// Move the store
auto *EntryStoreAccess = MSSA.getMemoryAccess(EntryStore);
auto *SideStoreAccess = MSSA.getMemoryAccess(SideStore);
// Before, the load will point to a phi of the EntryStore and SideStore.
auto *LoadAccess = cast<MemoryUse>(MSSA.getMemoryAccess(MergeLoad));
EXPECT_TRUE(isa<MemoryPhi>(LoadAccess->getDefiningAccess()));
MemoryPhi *MergePhi = cast<MemoryPhi>(LoadAccess->getDefiningAccess());
EXPECT_EQ(MergePhi->getIncomingValue(1), EntryStoreAccess);
EXPECT_EQ(MergePhi->getIncomingValue(0), SideStoreAccess);
// Move the store before the entry store
SideStore->moveBefore(*EntryStore->getParent(), EntryStore->getIterator());
Updater.moveBefore(SideStoreAccess, EntryStoreAccess);
// After, it's a phi of the entry store.
EXPECT_EQ(MergePhi->getIncomingValue(0), EntryStoreAccess);
EXPECT_EQ(MergePhi->getIncomingValue(1), EntryStoreAccess);
MSSA.verifyMemorySSA();
// Now move the store to the right branch
SideStore->moveBefore(*Right, Right->begin());
Updater.moveToPlace(SideStoreAccess, Right, MemorySSA::Beginning);
MSSA.verifyMemorySSA();
EXPECT_EQ(MergePhi->getIncomingValue(0), EntryStoreAccess);
EXPECT_EQ(MergePhi->getIncomingValue(1), SideStoreAccess);
// Now move it before the load
SideStore->moveBefore(MergeLoad);
Updater.moveBefore(SideStoreAccess, LoadAccess);
EXPECT_EQ(MergePhi->getIncomingValue(0), EntryStoreAccess);
EXPECT_EQ(MergePhi->getIncomingValue(1), EntryStoreAccess);
MSSA.verifyMemorySSA();
}
TEST_F(MemorySSATest, RemoveAPhi) {
// We create a diamond where there is a store on one side, and then a load
// after the merge point. This enables us to test a bunch of different
// removal cases.
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry(BasicBlock::Create(C, "", F));
BasicBlock *Left(BasicBlock::Create(C, "", F));
BasicBlock *Right(BasicBlock::Create(C, "", F));
BasicBlock *Merge(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
B.CreateCondBr(B.getTrue(), Left, Right);
B.SetInsertPoint(Left);
Argument *PointerArg = &*F->arg_begin();
StoreInst *StoreInst = B.CreateStore(B.getInt8(16), PointerArg);
BranchInst::Create(Merge, Left);
BranchInst::Create(Merge, Right);
B.SetInsertPoint(Merge);
LoadInst *LoadInst = B.CreateLoad(B.getInt8Ty(), PointerArg);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAUpdater Updater(&MSSA);
// Before, the load will be a use of a phi<store, liveonentry>.
MemoryUse *LoadAccess = cast<MemoryUse>(MSSA.getMemoryAccess(LoadInst));
MemoryDef *StoreAccess = cast<MemoryDef>(MSSA.getMemoryAccess(StoreInst));
MemoryAccess *DefiningAccess = LoadAccess->getDefiningAccess();
EXPECT_TRUE(isa<MemoryPhi>(DefiningAccess));
// Kill the store
Updater.removeMemoryAccess(StoreAccess);
MemoryPhi *MP = cast<MemoryPhi>(DefiningAccess);
// Verify the phi ended up as liveonentry, liveonentry
for (auto &Op : MP->incoming_values())
EXPECT_TRUE(MSSA.isLiveOnEntryDef(cast<MemoryAccess>(Op.get())));
// Replace the phi uses with the live on entry def
MP->replaceAllUsesWith(MSSA.getLiveOnEntryDef());
// Verify the load is now defined by liveOnEntryDef
EXPECT_TRUE(MSSA.isLiveOnEntryDef(LoadAccess->getDefiningAccess()));
// Remove the PHI
Updater.removeMemoryAccess(MP);
MSSA.verifyMemorySSA();
}
TEST_F(MemorySSATest, RemoveMemoryAccess) {
// We create a diamond where there is a store on one side, and then a load
// after the merge point. This enables us to test a bunch of different
// removal cases.
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry(BasicBlock::Create(C, "", F));
BasicBlock *Left(BasicBlock::Create(C, "", F));
BasicBlock *Right(BasicBlock::Create(C, "", F));
BasicBlock *Merge(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
B.CreateCondBr(B.getTrue(), Left, Right);
B.SetInsertPoint(Left);
Argument *PointerArg = &*F->arg_begin();
StoreInst *StoreInst = B.CreateStore(B.getInt8(16), PointerArg);
BranchInst::Create(Merge, Left);
BranchInst::Create(Merge, Right);
B.SetInsertPoint(Merge);
LoadInst *LoadInst = B.CreateLoad(B.getInt8Ty(), PointerArg);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
MemorySSAUpdater Updater(&MSSA);
// Before, the load will be a use of a phi<store, liveonentry>. It should be
// the same after.
MemoryUse *LoadAccess = cast<MemoryUse>(MSSA.getMemoryAccess(LoadInst));
MemoryDef *StoreAccess = cast<MemoryDef>(MSSA.getMemoryAccess(StoreInst));
MemoryAccess *DefiningAccess = LoadAccess->getDefiningAccess();
EXPECT_TRUE(isa<MemoryPhi>(DefiningAccess));
// The load is currently clobbered by one of the phi arguments, so the walker
// should determine the clobbering access as the phi.
EXPECT_EQ(DefiningAccess, Walker->getClobberingMemoryAccess(LoadInst));
Updater.removeMemoryAccess(StoreAccess);
MSSA.verifyMemorySSA();
// After the removeaccess, let's see if we got the right accesses
// The load should still point to the phi ...
EXPECT_EQ(DefiningAccess, LoadAccess->getDefiningAccess());
// but we should now get live on entry for the clobbering definition of the
// load, since it will walk past the phi node since every argument is the
// same.
// XXX: This currently requires either removing the phi or resetting optimized
// on the load
EXPECT_FALSE(
MSSA.isLiveOnEntryDef(Walker->getClobberingMemoryAccess(LoadInst)));
// If we reset optimized, we get live on entry.
LoadAccess->resetOptimized();
EXPECT_TRUE(
MSSA.isLiveOnEntryDef(Walker->getClobberingMemoryAccess(LoadInst)));
// The phi should now be a two entry phi with two live on entry defs.
for (const auto &Op : DefiningAccess->operands()) {
MemoryAccess *Operand = cast<MemoryAccess>(&*Op);
EXPECT_TRUE(MSSA.isLiveOnEntryDef(Operand));
}
// Now we try to remove the single valued phi
Updater.removeMemoryAccess(DefiningAccess);
MSSA.verifyMemorySSA();
// Now the load should be a load of live on entry.
EXPECT_TRUE(MSSA.isLiveOnEntryDef(LoadAccess->getDefiningAccess()));
}
// We had a bug with caching where the walker would report MemoryDef#3's clobber
// (below) was MemoryDef#1.
//
// define void @F(i8*) {
// %A = alloca i8, i8 1
// ; 1 = MemoryDef(liveOnEntry)
// store i8 0, i8* %A
// ; 2 = MemoryDef(1)
// store i8 1, i8* %A
// ; 3 = MemoryDef(2)
// store i8 2, i8* %A
// }
TEST_F(MemorySSATest, TestTripleStore) {
F = Function::Create(FunctionType::get(B.getVoidTy(), {}, false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "", F));
Type *Int8 = Type::getInt8Ty(C);
Value *Alloca = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "A");
StoreInst *S1 = B.CreateStore(ConstantInt::get(Int8, 0), Alloca);
StoreInst *S2 = B.CreateStore(ConstantInt::get(Int8, 1), Alloca);
StoreInst *S3 = B.CreateStore(ConstantInt::get(Int8, 2), Alloca);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
unsigned I = 0;
for (StoreInst *V : {S1, S2, S3}) {
// Everything should be clobbered by its defining access
MemoryAccess *DefiningAccess = MSSA.getMemoryAccess(V)->getDefiningAccess();
MemoryAccess *WalkerClobber = Walker->getClobberingMemoryAccess(V);
EXPECT_EQ(DefiningAccess, WalkerClobber)
<< "Store " << I << " doesn't have the correct clobbering access";
// EXPECT_EQ expands such that if we increment I above, it won't get
// incremented except when we try to print the error message.
++I;
}
}
// ...And fixing the above bug made it obvious that, when walking, MemorySSA's
// walker was caching the initial node it walked. This was fine (albeit
// mostly redundant) unless the initial node being walked is a clobber for the
// query. In that case, we'd cache that the node clobbered itself.
TEST_F(MemorySSATest, TestStoreAndLoad) {
F = Function::Create(FunctionType::get(B.getVoidTy(), {}, false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "", F));
Type *Int8 = Type::getInt8Ty(C);
Value *Alloca = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "A");
Instruction *SI = B.CreateStore(ConstantInt::get(Int8, 0), Alloca);
Instruction *LI = B.CreateLoad(Int8, Alloca);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
MemoryAccess *LoadClobber = Walker->getClobberingMemoryAccess(LI);
EXPECT_EQ(LoadClobber, MSSA.getMemoryAccess(SI));
EXPECT_TRUE(MSSA.isLiveOnEntryDef(Walker->getClobberingMemoryAccess(SI)));
}
// Another bug (related to the above two fixes): It was noted that, given the
// following code:
// ; 1 = MemoryDef(liveOnEntry)
// store i8 0, i8* %1
//
// ...A query to getClobberingMemoryAccess(MemoryAccess*, MemoryLocation) would
// hand back the store (correctly). A later call to
// getClobberingMemoryAccess(const Instruction*) would also hand back the store
// (incorrectly; it should return liveOnEntry).
//
// This test checks that repeated calls to either function returns what they're
// meant to.
TEST_F(MemorySSATest, TestStoreDoubleQuery) {
F = Function::Create(FunctionType::get(B.getVoidTy(), {}, false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "", F));
Type *Int8 = Type::getInt8Ty(C);
Value *Alloca = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "A");
StoreInst *SI = B.CreateStore(ConstantInt::get(Int8, 0), Alloca);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
MemoryAccess *StoreAccess = MSSA.getMemoryAccess(SI);
MemoryLocation StoreLoc = MemoryLocation::get(SI);
MemoryAccess *Clobber =
Walker->getClobberingMemoryAccess(StoreAccess, StoreLoc);
MemoryAccess *LiveOnEntry = Walker->getClobberingMemoryAccess(SI);
EXPECT_EQ(Clobber, StoreAccess);
EXPECT_TRUE(MSSA.isLiveOnEntryDef(LiveOnEntry));
// Try again (with entries in the cache already) for good measure...
Clobber = Walker->getClobberingMemoryAccess(StoreAccess, StoreLoc);
LiveOnEntry = Walker->getClobberingMemoryAccess(SI);
EXPECT_EQ(Clobber, StoreAccess);
EXPECT_TRUE(MSSA.isLiveOnEntryDef(LiveOnEntry));
}
// Bug: During phi optimization, the walker wouldn't cache to the proper result
// in the farthest-walked BB.
//
// Specifically, it would assume that whatever we walked to was a clobber.
// "Whatever we walked to" isn't a clobber if we hit a cache entry.
//
// ...So, we need a test case that looks like:
// A
// / \
// B |
// \ /
// C
//
// Where, when we try to optimize a thing in 'C', a blocker is found in 'B'.
// The walk must determine that the blocker exists by using cache entries *while
// walking* 'B'.
TEST_F(MemorySSATest, PartialWalkerCacheWithPhis) {
F = Function::Create(FunctionType::get(B.getVoidTy(), {}, false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "A", F));
Type *Int8 = Type::getInt8Ty(C);
Constant *One = ConstantInt::get(Int8, 1);
Constant *Zero = ConstantInt::get(Int8, 0);
Value *AllocA = B.CreateAlloca(Int8, One, "a");
Value *AllocB = B.CreateAlloca(Int8, One, "b");
BasicBlock *IfThen = BasicBlock::Create(C, "B", F);
BasicBlock *IfEnd = BasicBlock::Create(C, "C", F);
B.CreateCondBr(UndefValue::get(Type::getInt1Ty(C)), IfThen, IfEnd);
B.SetInsertPoint(IfThen);
Instruction *FirstStore = B.CreateStore(Zero, AllocA);
B.CreateStore(Zero, AllocB);
Instruction *ALoad0 = B.CreateLoad(Int8, AllocA, "");
Instruction *BStore = B.CreateStore(Zero, AllocB);
// Due to use optimization/etc. we make a store to A, which is removed after
// we build MSSA. This helps keep the test case simple-ish.
Instruction *KillStore = B.CreateStore(Zero, AllocA);
Instruction *ALoad = B.CreateLoad(Int8, AllocA, "");
B.CreateBr(IfEnd);
B.SetInsertPoint(IfEnd);
Instruction *BelowPhi = B.CreateStore(Zero, AllocA);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
MemorySSAUpdater Updater(&MSSA);
// Kill `KillStore`; it exists solely so that the load after it won't be
// optimized to FirstStore.
Updater.removeMemoryAccess(MSSA.getMemoryAccess(KillStore));
KillStore->eraseFromParent();
auto *ALoadMA = cast<MemoryUse>(MSSA.getMemoryAccess(ALoad));
EXPECT_EQ(ALoadMA->getDefiningAccess(), MSSA.getMemoryAccess(BStore));
// Populate the cache for the store to AllocB directly after FirstStore. It
// should point to something in block B (so something in D can't be optimized
// to it).
MemoryAccess *Load0Clobber = Walker->getClobberingMemoryAccess(ALoad0);
EXPECT_EQ(MSSA.getMemoryAccess(FirstStore), Load0Clobber);
// If the bug exists, this will introduce a bad cache entry for %a on BStore.
// It will point to the store to %b after FirstStore. This only happens during
// phi optimization.
MemoryAccess *BottomClobber = Walker->getClobberingMemoryAccess(BelowPhi);
MemoryAccess *Phi = MSSA.getMemoryAccess(IfEnd);
EXPECT_EQ(BottomClobber, Phi);
// This query will first check the cache for {%a, BStore}. It should point to
// FirstStore, not to the store after FirstStore.
MemoryAccess *UseClobber = Walker->getClobberingMemoryAccess(ALoad);
EXPECT_EQ(UseClobber, MSSA.getMemoryAccess(FirstStore));
}
// Test that our walker properly handles loads with the invariant group
// attribute. It's a bit hacky, since we add the invariant attribute *after*
// building MSSA. Otherwise, the use optimizer will optimize it for us, which
// isn't what we want.
// FIXME: It may be easier/cleaner to just add an 'optimize uses?' flag to MSSA.
TEST_F(MemorySSATest, WalkerInvariantLoadOpt) {
F = Function::Create(FunctionType::get(B.getVoidTy(), {}, false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "", F));
Type *Int8 = Type::getInt8Ty(C);
Constant *One = ConstantInt::get(Int8, 1);
Value *AllocA = B.CreateAlloca(Int8, One, "");
Instruction *Store = B.CreateStore(One, AllocA);
Instruction *Load = B.CreateLoad(Int8, AllocA);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
auto *LoadMA = cast<MemoryUse>(MSSA.getMemoryAccess(Load));
auto *StoreMA = cast<MemoryDef>(MSSA.getMemoryAccess(Store));
EXPECT_EQ(LoadMA->getDefiningAccess(), StoreMA);
// ...At the time of writing, no cache should exist for LoadMA. Be a bit
// flexible to future changes.
Walker->invalidateInfo(LoadMA);
Load->setMetadata(LLVMContext::MD_invariant_load, MDNode::get(C, {}));
MemoryAccess *LoadClobber = Walker->getClobberingMemoryAccess(LoadMA);
EXPECT_EQ(LoadClobber, MSSA.getLiveOnEntryDef());
}
// Test loads get reoptimized properly by the walker.
TEST_F(MemorySSATest, WalkerReopt) {
F = Function::Create(FunctionType::get(B.getVoidTy(), {}, false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "", F));
Type *Int8 = Type::getInt8Ty(C);
Value *AllocaA = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "A");
Instruction *SIA = B.CreateStore(ConstantInt::get(Int8, 0), AllocaA);
Value *AllocaB = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "B");
Instruction *SIB = B.CreateStore(ConstantInt::get(Int8, 0), AllocaB);
Instruction *LIA = B.CreateLoad(Int8, AllocaA);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
MemorySSAUpdater Updater(&MSSA);
MemoryAccess *LoadClobber = Walker->getClobberingMemoryAccess(LIA);
MemoryUse *LoadAccess = cast<MemoryUse>(MSSA.getMemoryAccess(LIA));
EXPECT_EQ(LoadClobber, MSSA.getMemoryAccess(SIA));
EXPECT_TRUE(MSSA.isLiveOnEntryDef(Walker->getClobberingMemoryAccess(SIA)));
Updater.removeMemoryAccess(LoadAccess);
// Create the load memory access pointing to an unoptimized place.
MemoryUse *NewLoadAccess = cast<MemoryUse>(Updater.createMemoryAccessInBB(
LIA, MSSA.getMemoryAccess(SIB), LIA->getParent(), MemorySSA::End));
// This should it cause it to be optimized
EXPECT_EQ(Walker->getClobberingMemoryAccess(NewLoadAccess), LoadClobber);
EXPECT_EQ(NewLoadAccess->getDefiningAccess(), LoadClobber);
}
// Test out MemorySSAUpdater::moveBefore
TEST_F(MemorySSATest, MoveAboveMemoryDef) {
F = Function::Create(FunctionType::get(B.getVoidTy(), {}, false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "", F));
Type *Int8 = Type::getInt8Ty(C);
Value *A = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "A");
Value *B_ = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "B");
Value *C = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "C");
StoreInst *StoreA0 = B.CreateStore(ConstantInt::get(Int8, 0), A);
StoreInst *StoreB = B.CreateStore(ConstantInt::get(Int8, 0), B_);
LoadInst *LoadB = B.CreateLoad(Int8, B_);
StoreInst *StoreA1 = B.CreateStore(ConstantInt::get(Int8, 4), A);
StoreInst *StoreC = B.CreateStore(ConstantInt::get(Int8, 4), C);
StoreInst *StoreA2 = B.CreateStore(ConstantInt::get(Int8, 4), A);
LoadInst *LoadC = B.CreateLoad(Int8, C);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker &Walker = *Analyses->Walker;
MemorySSAUpdater Updater(&MSSA);
StoreC->moveBefore(StoreB);
Updater.moveBefore(cast<MemoryDef>(MSSA.getMemoryAccess(StoreC)),
cast<MemoryDef>(MSSA.getMemoryAccess(StoreB)));
MSSA.verifyMemorySSA();
EXPECT_EQ(MSSA.getMemoryAccess(StoreB)->getDefiningAccess(),
MSSA.getMemoryAccess(StoreC));
EXPECT_EQ(MSSA.getMemoryAccess(StoreC)->getDefiningAccess(),
MSSA.getMemoryAccess(StoreA0));
EXPECT_EQ(MSSA.getMemoryAccess(StoreA2)->getDefiningAccess(),
MSSA.getMemoryAccess(StoreA1));
EXPECT_EQ(Walker.getClobberingMemoryAccess(LoadB),
MSSA.getMemoryAccess(StoreB));
EXPECT_EQ(Walker.getClobberingMemoryAccess(LoadC),
MSSA.getMemoryAccess(StoreC));
// exercise block numbering
EXPECT_TRUE(MSSA.locallyDominates(MSSA.getMemoryAccess(StoreC),
MSSA.getMemoryAccess(StoreB)));
EXPECT_TRUE(MSSA.locallyDominates(MSSA.getMemoryAccess(StoreA1),
MSSA.getMemoryAccess(StoreA2)));
}
TEST_F(MemorySSATest, Irreducible) {
// Create the equivalent of
// x = something
// if (...)
// goto second_loop_entry
// while (...) {
// second_loop_entry:
// }
// use(x)
SmallVector<PHINode *, 8> Inserted;
IRBuilder<> B(C);
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
// Make blocks
BasicBlock *IfBB = BasicBlock::Create(C, "if", F);
BasicBlock *LoopStartBB = BasicBlock::Create(C, "loopstart", F);
BasicBlock *LoopMainBB = BasicBlock::Create(C, "loopmain", F);
BasicBlock *AfterLoopBB = BasicBlock::Create(C, "afterloop", F);
B.SetInsertPoint(IfBB);
B.CreateCondBr(B.getTrue(), LoopMainBB, LoopStartBB);
B.SetInsertPoint(LoopStartBB);
B.CreateBr(LoopMainBB);
B.SetInsertPoint(LoopMainBB);
B.CreateCondBr(B.getTrue(), LoopStartBB, AfterLoopBB);
B.SetInsertPoint(AfterLoopBB);
Argument *FirstArg = &*F->arg_begin();
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAUpdater Updater(&MSSA);
// Create the load memory acccess
LoadInst *LoadInst = B.CreateLoad(B.getInt8Ty(), FirstArg);
MemoryUse *LoadAccess = cast<MemoryUse>(Updater.createMemoryAccessInBB(
LoadInst, nullptr, AfterLoopBB, MemorySSA::Beginning));
Updater.insertUse(LoadAccess);
MSSA.verifyMemorySSA();
}
TEST_F(MemorySSATest, MoveToBeforeLiveOnEntryInvalidatesCache) {
// Create:
// %1 = alloca i8
// ; 1 = MemoryDef(liveOnEntry)
// store i8 0, i8* %1
// ; 2 = MemoryDef(1)
// store i8 0, i8* %1
//
// ...And be sure that MSSA's caching doesn't give us `1` for the clobber of
// `2` after `1` is removed.
IRBuilder<> B(C);
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry = BasicBlock::Create(C, "if", F);
B.SetInsertPoint(Entry);
Value *A = B.CreateAlloca(B.getInt8Ty());
StoreInst *StoreA = B.CreateStore(B.getInt8(0), A);
StoreInst *StoreB = B.CreateStore(B.getInt8(0), A);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
auto *DefA = cast<MemoryDef>(MSSA.getMemoryAccess(StoreA));
auto *DefB = cast<MemoryDef>(MSSA.getMemoryAccess(StoreB));
MemoryAccess *BClobber = MSSA.getWalker()->getClobberingMemoryAccess(DefB);
ASSERT_EQ(DefA, BClobber);
MemorySSAUpdater(&MSSA).removeMemoryAccess(DefA);
StoreA->eraseFromParent();
EXPECT_EQ(DefB->getDefiningAccess(), MSSA.getLiveOnEntryDef());
EXPECT_EQ(MSSA.getWalker()->getClobberingMemoryAccess(DefB),
MSSA.getLiveOnEntryDef())
<< "(DefA = " << DefA << ")";
}
TEST_F(MemorySSATest, RemovingDefInvalidatesCache) {
// Create:
// %x = alloca i8
// %y = alloca i8
// ; 1 = MemoryDef(liveOnEntry)
// store i8 0, i8* %x
// ; 2 = MemoryDef(1)
// store i8 0, i8* %y
// ; 3 = MemoryDef(2)
// store i8 0, i8* %x
//
// And be sure that MSSA's caching handles the removal of def `1`
// appropriately.
IRBuilder<> B(C);
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BasicBlock *Entry = BasicBlock::Create(C, "if", F);
B.SetInsertPoint(Entry);
Value *X = B.CreateAlloca(B.getInt8Ty());
Value *Y = B.CreateAlloca(B.getInt8Ty());
StoreInst *StoreX1 = B.CreateStore(B.getInt8(0), X);
StoreInst *StoreY = B.CreateStore(B.getInt8(0), Y);
StoreInst *StoreX2 = B.CreateStore(B.getInt8(0), X);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
auto *DefX1 = cast<MemoryDef>(MSSA.getMemoryAccess(StoreX1));
auto *DefY = cast<MemoryDef>(MSSA.getMemoryAccess(StoreY));
auto *DefX2 = cast<MemoryDef>(MSSA.getMemoryAccess(StoreX2));
EXPECT_EQ(DefX2->getDefiningAccess(), DefY);
MemoryAccess *X2Clobber = MSSA.getWalker()->getClobberingMemoryAccess(DefX2);
ASSERT_EQ(DefX1, X2Clobber);
MemorySSAUpdater(&MSSA).removeMemoryAccess(DefX1);
StoreX1->eraseFromParent();
EXPECT_EQ(DefX2->getDefiningAccess(), DefY);
EXPECT_EQ(MSSA.getWalker()->getClobberingMemoryAccess(DefX2),
MSSA.getLiveOnEntryDef())
<< "(DefX1 = " << DefX1 << ")";
}
// Test Must alias for optimized uses
TEST_F(MemorySSATest, TestLoadMustAlias) {
F = Function::Create(FunctionType::get(B.getVoidTy(), {}, false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "", F));
Type *Int8 = Type::getInt8Ty(C);
Value *AllocaA = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "A");
Value *AllocaB = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "B");
B.CreateStore(ConstantInt::get(Int8, 1), AllocaB);
// Check load from LOE
LoadInst *LA1 = B.CreateLoad(Int8, AllocaA, "");
// Check load alias cached for second load
LoadInst *LA2 = B.CreateLoad(Int8, AllocaA, "");
B.CreateStore(ConstantInt::get(Int8, 1), AllocaA);
// Check load from store/def
LoadInst *LA3 = B.CreateLoad(Int8, AllocaA, "");
// Check load alias cached for second load
LoadInst *LA4 = B.CreateLoad(Int8, AllocaA, "");
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MSSA.ensureOptimizedUses();
unsigned I = 0;
for (LoadInst *V : {LA1, LA2}) {
MemoryUse *MemUse = dyn_cast_or_null<MemoryUse>(MSSA.getMemoryAccess(V));
EXPECT_EQ(MemUse->getOptimizedAccessType(), None)
<< "Load " << I << " doesn't have the correct alias information";
// EXPECT_EQ expands such that if we increment I above, it won't get
// incremented except when we try to print the error message.
++I;
}
for (LoadInst *V : {LA3, LA4}) {
MemoryUse *MemUse = dyn_cast_or_null<MemoryUse>(MSSA.getMemoryAccess(V));
EXPECT_EQ(MemUse->getOptimizedAccessType().getValue(),
AliasResult::MustAlias)
<< "Load " << I << " doesn't have the correct alias information";
// EXPECT_EQ expands such that if we increment I above, it won't get
// incremented except when we try to print the error message.
++I;
}
}
// Test Must alias for optimized defs.
TEST_F(MemorySSATest, TestStoreMustAlias) {
F = Function::Create(FunctionType::get(B.getVoidTy(), {}, false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "", F));
Type *Int8 = Type::getInt8Ty(C);
Value *AllocaA = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "A");
Value *AllocaB = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "B");
StoreInst *SA1 = B.CreateStore(ConstantInt::get(Int8, 1), AllocaA);
StoreInst *SB1 = B.CreateStore(ConstantInt::get(Int8, 1), AllocaB);
StoreInst *SA2 = B.CreateStore(ConstantInt::get(Int8, 2), AllocaA);
StoreInst *SB2 = B.CreateStore(ConstantInt::get(Int8, 2), AllocaB);
StoreInst *SA3 = B.CreateStore(ConstantInt::get(Int8, 3), AllocaA);
StoreInst *SB3 = B.CreateStore(ConstantInt::get(Int8, 3), AllocaB);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
unsigned I = 0;
for (StoreInst *V : {SA1, SB1, SA2, SB2, SA3, SB3}) {
MemoryDef *MemDef = dyn_cast_or_null<MemoryDef>(MSSA.getMemoryAccess(V));
EXPECT_EQ(MemDef->isOptimized(), false)
<< "Store " << I << " is optimized from the start?";
EXPECT_EQ(MemDef->getOptimizedAccessType(), None)
<< "Store " << I
<< " has correct alias information before being optimized?";
if (V == SA1)
Walker->getClobberingMemoryAccess(V);
else {
MemoryAccess *Def = MemDef->getDefiningAccess();
MemoryAccess *Clob = Walker->getClobberingMemoryAccess(V);
EXPECT_NE(Def, Clob) << "Store " << I
<< " has Defining Access equal to Clobbering Access";
}
EXPECT_EQ(MemDef->isOptimized(), true)
<< "Store " << I << " was not optimized";
if (I == 0 || I == 1)
EXPECT_EQ(MemDef->getOptimizedAccessType(), None)
<< "Store " << I << " doesn't have the correct alias information";
else
EXPECT_EQ(MemDef->getOptimizedAccessType().getValue(),
AliasResult::MustAlias)
<< "Store " << I << " doesn't have the correct alias information";
// EXPECT_EQ expands such that if we increment I above, it won't get
// incremented except when we try to print the error message.
++I;
}
}
// Test May alias for optimized uses.
TEST_F(MemorySSATest, TestLoadMayAlias) {
F = Function::Create(FunctionType::get(B.getVoidTy(),
{B.getInt8PtrTy(), B.getInt8PtrTy()},
false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "", F));
Type *Int8 = Type::getInt8Ty(C);
auto *ArgIt = F->arg_begin();
Argument *PointerA = &*ArgIt;
Argument *PointerB = &*(++ArgIt);
B.CreateStore(ConstantInt::get(Int8, 1), PointerB);
LoadInst *LA1 = B.CreateLoad(Int8, PointerA, "");
B.CreateStore(ConstantInt::get(Int8, 0), PointerA);
LoadInst *LB1 = B.CreateLoad(Int8, PointerB, "");
B.CreateStore(ConstantInt::get(Int8, 0), PointerA);
LoadInst *LA2 = B.CreateLoad(Int8, PointerA, "");
B.CreateStore(ConstantInt::get(Int8, 0), PointerB);
LoadInst *LB2 = B.CreateLoad(Int8, PointerB, "");
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MSSA.ensureOptimizedUses();
unsigned I = 0;
for (LoadInst *V : {LA1, LB1}) {
MemoryUse *MemUse = dyn_cast_or_null<MemoryUse>(MSSA.getMemoryAccess(V));
EXPECT_EQ(MemUse->getOptimizedAccessType().getValue(),
AliasResult::MayAlias)
<< "Load " << I << " doesn't have the correct alias information";
// EXPECT_EQ expands such that if we increment I above, it won't get
// incremented except when we try to print the error message.
++I;
}
for (LoadInst *V : {LA2, LB2}) {
MemoryUse *MemUse = dyn_cast_or_null<MemoryUse>(MSSA.getMemoryAccess(V));
EXPECT_EQ(MemUse->getOptimizedAccessType().getValue(),
AliasResult::MustAlias)
<< "Load " << I << " doesn't have the correct alias information";
// EXPECT_EQ expands such that if we increment I above, it won't get
// incremented except when we try to print the error message.
++I;
}
}
// Test May alias for optimized defs.
TEST_F(MemorySSATest, TestStoreMayAlias) {
F = Function::Create(FunctionType::get(B.getVoidTy(),
{B.getInt8PtrTy(), B.getInt8PtrTy()},
false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "", F));
Type *Int8 = Type::getInt8Ty(C);
auto *ArgIt = F->arg_begin();
Argument *PointerA = &*ArgIt;
Argument *PointerB = &*(++ArgIt);
Value *AllocaC = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "C");
// Store into arg1, must alias because it's LOE => must
StoreInst *SA1 = B.CreateStore(ConstantInt::get(Int8, 0), PointerA);
// Store into arg2, may alias store to arg1 => may
StoreInst *SB1 = B.CreateStore(ConstantInt::get(Int8, 1), PointerB);
// Store into aloca, no alias with args, so must alias LOE => must
StoreInst *SC1 = B.CreateStore(ConstantInt::get(Int8, 2), AllocaC);
// Store into arg1, may alias store to arg2 => may
StoreInst *SA2 = B.CreateStore(ConstantInt::get(Int8, 3), PointerA);
// Store into arg2, may alias store to arg1 => may
StoreInst *SB2 = B.CreateStore(ConstantInt::get(Int8, 4), PointerB);
// Store into aloca, no alias with args, so must alias SC1 => must
StoreInst *SC2 = B.CreateStore(ConstantInt::get(Int8, 5), AllocaC);
// Store into arg2, must alias store to arg2 => must
StoreInst *SB3 = B.CreateStore(ConstantInt::get(Int8, 6), PointerB);
std::initializer_list<StoreInst *> Sts = {SA1, SB1, SC1, SA2, SB2, SC2, SB3};
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
unsigned I = 0;
for (StoreInst *V : Sts) {
MemoryDef *MemDef = dyn_cast_or_null<MemoryDef>(MSSA.getMemoryAccess(V));
EXPECT_EQ(MemDef->isOptimized(), false)
<< "Store " << I << " is optimized from the start?";
EXPECT_EQ(MemDef->getOptimizedAccessType(), None)
<< "Store " << I
<< " has correct alias information before being optimized?";
++I;
}
for (StoreInst *V : Sts)
Walker->getClobberingMemoryAccess(V);
I = 0;
for (StoreInst *V : Sts) {
MemoryDef *MemDef = dyn_cast_or_null<MemoryDef>(MSSA.getMemoryAccess(V));
EXPECT_EQ(MemDef->isOptimized(), true)
<< "Store " << I << " was not optimized";
if (I == 1 || I == 3 || I == 4)
EXPECT_EQ(MemDef->getOptimizedAccessType().getValue(),
AliasResult::MayAlias)
<< "Store " << I << " doesn't have the correct alias information";
else if (I == 0 || I == 2)
EXPECT_EQ(MemDef->getOptimizedAccessType(), None)
<< "Store " << I << " doesn't have the correct alias information";
else
EXPECT_EQ(MemDef->getOptimizedAccessType().getValue(),
AliasResult::MustAlias)
<< "Store " << I << " doesn't have the correct alias information";
// EXPECT_EQ expands such that if we increment I above, it won't get
// incremented except when we try to print the error message.
++I;
}
}
TEST_F(MemorySSATest, LifetimeMarkersAreClobbers) {
// Example code:
// define void @a(i8* %foo) {
// %bar = getelementptr i8, i8* %foo, i64 1
// %baz = getelementptr i8, i8* %foo, i64 2
// store i8 0, i8* %foo
// store i8 0, i8* %bar
// call void @llvm.lifetime.end.p0i8(i64 3, i8* %foo)
// call void @llvm.lifetime.start.p0i8(i64 3, i8* %foo)
// store i8 0, i8* %foo
// store i8 0, i8* %bar
// call void @llvm.memset.p0i8(i8* %baz, i8 0, i64 1)
// ret void
// }
//
// Patterns like this are possible after inlining; the stores to %foo and %bar
// should both be clobbered by the lifetime.start call if they're dominated by
// it.
IRBuilder<> B(C);
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
// Make blocks
BasicBlock *Entry = BasicBlock::Create(C, "entry", F);
B.SetInsertPoint(Entry);
Value *Foo = &*F->arg_begin();
Value *Bar = B.CreateGEP(B.getInt8Ty(), Foo, B.getInt64(1), "bar");
Value *Baz = B.CreateGEP(B.getInt8Ty(), Foo, B.getInt64(2), "baz");
B.CreateStore(B.getInt8(0), Foo);
B.CreateStore(B.getInt8(0), Bar);
auto GetLifetimeIntrinsic = [&](Intrinsic::ID ID) {
return Intrinsic::getDeclaration(&M, ID, {Foo->getType()});
};
B.CreateCall(GetLifetimeIntrinsic(Intrinsic::lifetime_end),
{B.getInt64(3), Foo});
Instruction *LifetimeStart = B.CreateCall(
GetLifetimeIntrinsic(Intrinsic::lifetime_start), {B.getInt64(3), Foo});
Instruction *FooStore = B.CreateStore(B.getInt8(0), Foo);
Instruction *BarStore = B.CreateStore(B.getInt8(0), Bar);
Instruction *BazMemSet = B.CreateMemSet(Baz, B.getInt8(0), 1, Align(1));
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemoryAccess *LifetimeStartAccess = MSSA.getMemoryAccess(LifetimeStart);
ASSERT_NE(LifetimeStartAccess, nullptr);
MemoryAccess *FooAccess = MSSA.getMemoryAccess(FooStore);
ASSERT_NE(FooAccess, nullptr);
MemoryAccess *BarAccess = MSSA.getMemoryAccess(BarStore);
ASSERT_NE(BarAccess, nullptr);
MemoryAccess *BazAccess = MSSA.getMemoryAccess(BazMemSet);
ASSERT_NE(BazAccess, nullptr);
MemoryAccess *FooClobber =
MSSA.getWalker()->getClobberingMemoryAccess(FooAccess);
EXPECT_EQ(FooClobber, LifetimeStartAccess);
MemoryAccess *BarClobber =
MSSA.getWalker()->getClobberingMemoryAccess(BarAccess);
EXPECT_EQ(BarClobber, LifetimeStartAccess);
MemoryAccess *BazClobber =
MSSA.getWalker()->getClobberingMemoryAccess(BazAccess);
EXPECT_EQ(BazClobber, LifetimeStartAccess);
MemoryAccess *LifetimeStartClobber =
MSSA.getWalker()->getClobberingMemoryAccess(
LifetimeStartAccess, MemoryLocation::getAfter(Foo));
EXPECT_EQ(LifetimeStartClobber, LifetimeStartAccess);
}
TEST_F(MemorySSATest, DefOptimizationsAreInvalidatedOnMoving) {
IRBuilder<> B(C);
F = Function::Create(FunctionType::get(B.getVoidTy(), {B.getInt1Ty()}, false),
GlobalValue::ExternalLinkage, "F", &M);
// Make a CFG like
// entry
// / \
// a b
// \ /
// c
//
// Put a def in A and a def in B, move the def from A -> B, observe as the
// optimization is invalidated.
BasicBlock *Entry = BasicBlock::Create(C, "entry", F);
BasicBlock *BlockA = BasicBlock::Create(C, "a", F);
BasicBlock *BlockB = BasicBlock::Create(C, "b", F);
BasicBlock *BlockC = BasicBlock::Create(C, "c", F);
B.SetInsertPoint(Entry);
Type *Int8 = Type::getInt8Ty(C);
Value *Alloca = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "alloc");
StoreInst *StoreEntry = B.CreateStore(B.getInt8(0), Alloca);
B.CreateCondBr(B.getTrue(), BlockA, BlockB);
B.SetInsertPoint(BlockA);
StoreInst *StoreA = B.CreateStore(B.getInt8(1), Alloca);
B.CreateBr(BlockC);
B.SetInsertPoint(BlockB);
StoreInst *StoreB = B.CreateStore(B.getInt8(2), Alloca);
B.CreateBr(BlockC);
B.SetInsertPoint(BlockC);
B.CreateUnreachable();
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
auto *AccessEntry = cast<MemoryDef>(MSSA.getMemoryAccess(StoreEntry));
auto *StoreAEntry = cast<MemoryDef>(MSSA.getMemoryAccess(StoreA));
auto *StoreBEntry = cast<MemoryDef>(MSSA.getMemoryAccess(StoreB));
ASSERT_EQ(MSSA.getWalker()->getClobberingMemoryAccess(StoreAEntry),
AccessEntry);
ASSERT_TRUE(StoreAEntry->isOptimized());
ASSERT_EQ(MSSA.getWalker()->getClobberingMemoryAccess(StoreBEntry),
AccessEntry);
ASSERT_TRUE(StoreBEntry->isOptimized());
// Note that if we did InsertionPlace::Beginning, we don't go out of our way
// to invalidate the cache for StoreBEntry. If the user wants to actually do
// moves like these, it's up to them to ensure that nearby cache entries are
// correctly invalidated (which, in general, requires walking all instructions
// that the moved instruction dominates. So we probably shouldn't be doing
// moves like this in general. Still, works as a test-case. ;) )
MemorySSAUpdater(&MSSA).moveToPlace(StoreAEntry, BlockB,
MemorySSA::InsertionPlace::End);
ASSERT_FALSE(StoreAEntry->isOptimized());
ASSERT_EQ(MSSA.getWalker()->getClobberingMemoryAccess(StoreAEntry),
StoreBEntry);
}
TEST_F(MemorySSATest, TestOptimizedDefsAreProperUses) {
F = Function::Create(FunctionType::get(B.getVoidTy(),
{B.getInt8PtrTy(), B.getInt8PtrTy()},
false),
GlobalValue::ExternalLinkage, "F", &M);
B.SetInsertPoint(BasicBlock::Create(C, "", F));
Type *Int8 = Type::getInt8Ty(C);
Value *AllocA = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "A");
Value *AllocB = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "B");
StoreInst *StoreA = B.CreateStore(ConstantInt::get(Int8, 0), AllocA);
StoreInst *StoreB = B.CreateStore(ConstantInt::get(Int8, 1), AllocB);
StoreInst *StoreA2 = B.CreateStore(ConstantInt::get(Int8, 2), AllocA);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
// If these don't hold, there's no chance of the test result being useful.
ASSERT_EQ(Walker->getClobberingMemoryAccess(StoreA),
MSSA.getLiveOnEntryDef());
ASSERT_EQ(Walker->getClobberingMemoryAccess(StoreB),
MSSA.getLiveOnEntryDef());
auto *StoreAAccess = cast<MemoryDef>(MSSA.getMemoryAccess(StoreA));
auto *StoreA2Access = cast<MemoryDef>(MSSA.getMemoryAccess(StoreA2));
ASSERT_EQ(Walker->getClobberingMemoryAccess(StoreA2), StoreAAccess);
ASSERT_EQ(StoreA2Access->getOptimized(), StoreAAccess);
auto *StoreBAccess = cast<MemoryDef>(MSSA.getMemoryAccess(StoreB));
ASSERT_LT(StoreAAccess->getID(), StoreBAccess->getID());
ASSERT_LT(StoreBAccess->getID(), StoreA2Access->getID());
auto SortVecByID = [](std::vector<const MemoryDef *> &Defs) {
llvm::sort(Defs, [](const MemoryDef *LHS, const MemoryDef *RHS) {
return LHS->getID() < RHS->getID();
});
};
auto SortedUserList = [&](const MemoryDef *MD) {
std::vector<const MemoryDef *> Result;
transform(MD->users(), std::back_inserter(Result),
[](const User *U) { return cast<MemoryDef>(U); });
SortVecByID(Result);
return Result;
};
// Use std::vectors, since they have nice pretty-printing if the test fails.
// Parens are necessary because EXPECT_EQ is a macro, and we have commas in
// our init lists...
EXPECT_EQ(SortedUserList(StoreAAccess),
(std::vector<const MemoryDef *>{StoreBAccess, StoreA2Access}));
EXPECT_EQ(SortedUserList(StoreBAccess),
std::vector<const MemoryDef *>{StoreA2Access});
// StoreAAccess should be present twice, since it uses liveOnEntry for both
// its defining and optimized accesses. This is a bit awkward, and is not
// relied upon anywhere at the moment. If this is painful, we can fix it.
EXPECT_EQ(SortedUserList(cast<MemoryDef>(MSSA.getLiveOnEntryDef())),
(std::vector<const MemoryDef *>{StoreAAccess, StoreAAccess,
StoreBAccess}));
}
// entry
// |
// header
// / \
// body |
// \ /
// exit
// header:
// ; 1 = MemoryDef(liveOnEntry)
// body:
// ; 2 = MemoryDef(1)
// exit:
// ; 3 = MemoryPhi({body, 2}, {header, 1})
// ; 4 = MemoryDef(3); optimized to 3, cannot optimize thorugh phi.
// Insert edge: entry -> exit, check mssa Update is correct.
TEST_F(MemorySSATest, TestAddedEdgeToBlockWithPhiNotOpt) {
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
Argument *PointerArg = &*F->arg_begin();
BasicBlock *Entry(BasicBlock::Create(C, "entry", F));
BasicBlock *Header(BasicBlock::Create(C, "header", F));
BasicBlock *Body(BasicBlock::Create(C, "body", F));
BasicBlock *Exit(BasicBlock::Create(C, "exit", F));
B.SetInsertPoint(Entry);
BranchInst::Create(Header, Entry);
B.SetInsertPoint(Header);
B.CreateStore(B.getInt8(16), PointerArg);
B.CreateCondBr(B.getTrue(), Exit, Body);
B.SetInsertPoint(Body);
B.CreateStore(B.getInt8(16), PointerArg);
BranchInst::Create(Exit, Body);
B.SetInsertPoint(Exit);
StoreInst *S1 = B.CreateStore(B.getInt8(16), PointerArg);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
std::unique_ptr<MemorySSAUpdater> MSSAU =
std::make_unique<MemorySSAUpdater>(&MSSA);
MemoryPhi *Phi = MSSA.getMemoryAccess(Exit);
EXPECT_EQ(Phi, Walker->getClobberingMemoryAccess(S1));
// Alter CFG, add edge: entry -> exit
Entry->getTerminator()->eraseFromParent();
B.SetInsertPoint(Entry);
B.CreateCondBr(B.getTrue(), Header, Exit);
SmallVector<CFGUpdate, 1> Updates;
Updates.push_back({cfg::UpdateKind::Insert, Entry, Exit});
Analyses->DT.applyUpdates(Updates);
MSSAU->applyInsertUpdates(Updates, Analyses->DT);
EXPECT_EQ(Phi, Walker->getClobberingMemoryAccess(S1));
}
// entry
// |
// header
// / \
// body |
// \ /
// exit
// header:
// ; 1 = MemoryDef(liveOnEntry)
// body:
// ; 2 = MemoryDef(1)
// exit:
// ; 3 = MemoryPhi({body, 2}, {header, 1})
// ; 4 = MemoryDef(3); optimize this to 1 now, added edge should invalidate
// the optimized access.
// Insert edge: entry -> exit, check mssa Update is correct.
TEST_F(MemorySSATest, TestAddedEdgeToBlockWithPhiOpt) {
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
Argument *PointerArg = &*F->arg_begin();
Type *Int8 = Type::getInt8Ty(C);
BasicBlock *Entry(BasicBlock::Create(C, "entry", F));
BasicBlock *Header(BasicBlock::Create(C, "header", F));
BasicBlock *Body(BasicBlock::Create(C, "body", F));
BasicBlock *Exit(BasicBlock::Create(C, "exit", F));
B.SetInsertPoint(Entry);
Value *Alloca = B.CreateAlloca(Int8, ConstantInt::get(Int8, 1), "A");
BranchInst::Create(Header, Entry);
B.SetInsertPoint(Header);
StoreInst *S1 = B.CreateStore(B.getInt8(16), PointerArg);
B.CreateCondBr(B.getTrue(), Exit, Body);
B.SetInsertPoint(Body);
B.CreateStore(ConstantInt::get(Int8, 0), Alloca);
BranchInst::Create(Exit, Body);
B.SetInsertPoint(Exit);
StoreInst *S2 = B.CreateStore(B.getInt8(16), PointerArg);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
std::unique_ptr<MemorySSAUpdater> MSSAU =
std::make_unique<MemorySSAUpdater>(&MSSA);
MemoryDef *DefS1 = cast<MemoryDef>(MSSA.getMemoryAccess(S1));
EXPECT_EQ(DefS1, Walker->getClobberingMemoryAccess(S2));
// Alter CFG, add edge: entry -> exit
Entry->getTerminator()->eraseFromParent();
B.SetInsertPoint(Entry);
B.CreateCondBr(B.getTrue(), Header, Exit);
SmallVector<CFGUpdate, 1> Updates;
Updates.push_back({cfg::UpdateKind::Insert, Entry, Exit});
Analyses->DT.applyUpdates(Updates);
MSSAU->applyInsertUpdates(Updates, Analyses->DT);
MemoryPhi *Phi = MSSA.getMemoryAccess(Exit);
EXPECT_EQ(Phi, Walker->getClobberingMemoryAccess(S2));
}
// entry
// / |
// a |
// / \ |
// b c f
// \ / |
// d |
// \ /
// e
// f:
// ; 1 = MemoryDef(liveOnEntry)
// e:
// ; 2 = MemoryPhi({d, liveOnEntry}, {f, 1})
//
// Insert edge: f -> c, check update is correct.
// After update:
// f:
// ; 1 = MemoryDef(liveOnEntry)
// c:
// ; 3 = MemoryPhi({a, liveOnEntry}, {f, 1})
// d:
// ; 4 = MemoryPhi({b, liveOnEntry}, {c, 3})
// e:
// ; 2 = MemoryPhi({d, 4}, {f, 1})
TEST_F(MemorySSATest, TestAddedEdgeToBlockWithNoPhiAddNewPhis) {
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
Argument *PointerArg = &*F->arg_begin();
BasicBlock *Entry(BasicBlock::Create(C, "entry", F));
BasicBlock *ABlock(BasicBlock::Create(C, "a", F));
BasicBlock *BBlock(BasicBlock::Create(C, "b", F));
BasicBlock *CBlock(BasicBlock::Create(C, "c", F));
BasicBlock *DBlock(BasicBlock::Create(C, "d", F));
BasicBlock *EBlock(BasicBlock::Create(C, "e", F));
BasicBlock *FBlock(BasicBlock::Create(C, "f", F));
B.SetInsertPoint(Entry);
B.CreateCondBr(B.getTrue(), ABlock, FBlock);
B.SetInsertPoint(ABlock);
B.CreateCondBr(B.getTrue(), BBlock, CBlock);
B.SetInsertPoint(BBlock);
BranchInst::Create(DBlock, BBlock);
B.SetInsertPoint(CBlock);
BranchInst::Create(DBlock, CBlock);
B.SetInsertPoint(DBlock);
BranchInst::Create(EBlock, DBlock);
B.SetInsertPoint(FBlock);
B.CreateStore(B.getInt8(16), PointerArg);
BranchInst::Create(EBlock, FBlock);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
std::unique_ptr<MemorySSAUpdater> MSSAU =
std::make_unique<MemorySSAUpdater>(&MSSA);
// Alter CFG, add edge: f -> c
FBlock->getTerminator()->eraseFromParent();
B.SetInsertPoint(FBlock);
B.CreateCondBr(B.getTrue(), CBlock, EBlock);
SmallVector<CFGUpdate, 1> Updates;
Updates.push_back({cfg::UpdateKind::Insert, FBlock, CBlock});
Analyses->DT.applyUpdates(Updates);
MSSAU->applyInsertUpdates(Updates, Analyses->DT);
MemoryPhi *MPC = MSSA.getMemoryAccess(CBlock);
EXPECT_NE(MPC, nullptr);
MemoryPhi *MPD = MSSA.getMemoryAccess(DBlock);
EXPECT_NE(MPD, nullptr);
MemoryPhi *MPE = MSSA.getMemoryAccess(EBlock);
EXPECT_EQ(MPD, MPE->getIncomingValueForBlock(DBlock));
}
TEST_F(MemorySSATest, TestCallClobber) {
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
Value *Pointer1 = &*F->arg_begin();
BasicBlock *Entry(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
Value *Pointer2 = B.CreateGEP(B.getInt8Ty(), Pointer1, B.getInt64(1));
Instruction *StorePointer1 = B.CreateStore(B.getInt8(0), Pointer1);
Instruction *StorePointer2 = B.CreateStore(B.getInt8(0), Pointer2);
Instruction *MemSet = B.CreateMemSet(Pointer2, B.getInt8(0), 1, Align(1));
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
MemoryUseOrDef *Store1Access = MSSA.getMemoryAccess(StorePointer1);
MemoryUseOrDef *Store2Access = MSSA.getMemoryAccess(StorePointer2);
MemoryUseOrDef *MemSetAccess = MSSA.getMemoryAccess(MemSet);
MemoryAccess *Pointer1Clobber = Walker->getClobberingMemoryAccess(
MemSetAccess, MemoryLocation(Pointer1, LocationSize::precise(1)));
EXPECT_EQ(Pointer1Clobber, Store1Access);
MemoryAccess *Pointer2Clobber = Walker->getClobberingMemoryAccess(
MemSetAccess, MemoryLocation(Pointer2, LocationSize::precise(1)));
EXPECT_EQ(Pointer2Clobber, MemSetAccess);
MemoryAccess *MemSetClobber = Walker->getClobberingMemoryAccess(MemSetAccess);
EXPECT_EQ(MemSetClobber, Store2Access);
}
TEST_F(MemorySSATest, TestLoadClobber) {
F = Function::Create(
FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
Value *Pointer1 = &*F->arg_begin();
BasicBlock *Entry(BasicBlock::Create(C, "", F));
B.SetInsertPoint(Entry);
Value *Pointer2 = B.CreateGEP(B.getInt8Ty(), Pointer1, B.getInt64(1));
Instruction *LoadPointer1 =
B.CreateLoad(B.getInt8Ty(), Pointer1, /* Volatile */ true);
Instruction *LoadPointer2 =
B.CreateLoad(B.getInt8Ty(), Pointer2, /* Volatile */ true);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
MemoryUseOrDef *Load1Access = MSSA.getMemoryAccess(LoadPointer1);
MemoryUseOrDef *Load2Access = MSSA.getMemoryAccess(LoadPointer2);
// When providing a memory location, we should never return a load as the
// clobber.
MemoryAccess *Pointer1Clobber = Walker->getClobberingMemoryAccess(
Load2Access, MemoryLocation(Pointer1, LocationSize::precise(1)));
EXPECT_TRUE(MSSA.isLiveOnEntryDef(Pointer1Clobber));
MemoryAccess *Pointer2Clobber = Walker->getClobberingMemoryAccess(
Load2Access, MemoryLocation(Pointer2, LocationSize::precise(1)));
EXPECT_TRUE(MSSA.isLiveOnEntryDef(Pointer2Clobber));
MemoryAccess *Load2Clobber = Walker->getClobberingMemoryAccess(Load2Access);
EXPECT_EQ(Load2Clobber, Load1Access);
}
// We want to test if the location information are retained
// when the IsGuaranteedLoopInvariant function handles a
// memory access referring to a pointer defined in the entry
// block, hence automatically guaranteed to be loop invariant.
TEST_F(MemorySSATest, TestLoopInvariantEntryBlockPointer) {
SMDiagnostic E;
auto LocalM =
parseAssemblyString("define void @test(i64 %a0, i8* %a1, i1* %a2) {\n"
"entry:\n"
"%v0 = getelementptr i8, i8* %a1, i64 %a0\n"
"%v1 = bitcast i8* %v0 to i64*\n"
"%v2 = bitcast i8* %v0 to i32*\n"
"%v3 = load i1, i1* %a2\n"
"br i1 %v3, label %body, label %exit\n"
"body:\n"
"store i32 1, i32* %v2\n"
"br label %exit\n"
"exit:\n"
"store i64 0, i64* %v1\n"
"ret void\n"
"}",
E, C);
ASSERT_TRUE(LocalM);
F = LocalM->getFunction("test");
ASSERT_TRUE(F);
// Setup the analysis
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
// Find the exit block
for (auto &BB : *F) {
if (BB.getName() == "exit") {
// Get the store instruction
auto *SI = BB.getFirstNonPHI();
// Get the memory access and location
MemoryAccess *MA = MSSA.getMemoryAccess(SI);
MemoryLocation ML = MemoryLocation::get(SI);
// Use the 'upward_defs_iterator' which internally calls
// IsGuaranteedLoopInvariant
auto ItA = upward_defs_begin({MA, ML}, MSSA.getDomTree());
auto ItB =
upward_defs_begin({ItA->first, ItA->second}, MSSA.getDomTree());
// Check if the location information have been retained
EXPECT_TRUE(ItB->second.Size.isPrecise());
EXPECT_TRUE(ItB->second.Size.hasValue());
EXPECT_TRUE(ItB->second.Size.getValue() == 8);
}
}
}
TEST_F(MemorySSATest, TestInvariantGroup) {
SMDiagnostic E;
auto M = parseAssemblyString("declare void @f(i8*)\n"
"define i8 @test(i8* %p) {\n"
"entry:\n"
" store i8 42, i8* %p, !invariant.group !0\n"
" call void @f(i8* %p)\n"
" %v = load i8, i8* %p, !invariant.group !0\n"
" ret i8 %v\n"
"}\n"
"!0 = !{}",
E, C);
ASSERT_TRUE(M);
F = M->getFunction("test");
ASSERT_TRUE(F);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAWalker *Walker = Analyses->Walker;
auto &BB = F->getEntryBlock();
auto &SI = cast<StoreInst>(*BB.begin());
auto &Call = cast<CallBase>(*std::next(BB.begin()));
auto &LI = cast<LoadInst>(*std::next(std::next(BB.begin())));
{
MemoryAccess *SAccess = MSSA.getMemoryAccess(&SI);
MemoryAccess *LAccess = MSSA.getMemoryAccess(&LI);
MemoryAccess *SClobber = Walker->getClobberingMemoryAccess(SAccess);
EXPECT_TRUE(MSSA.isLiveOnEntryDef(SClobber));
MemoryAccess *LClobber = Walker->getClobberingMemoryAccess(LAccess);
EXPECT_EQ(SAccess, LClobber);
}
// remove store and verify that the memory accesses still make sense
MemorySSAUpdater Updater(&MSSA);
Updater.removeMemoryAccess(&SI);
SI.eraseFromParent();
{
MemoryAccess *CallAccess = MSSA.getMemoryAccess(&Call);
MemoryAccess *LAccess = MSSA.getMemoryAccess(&LI);
MemoryAccess *LClobber = Walker->getClobberingMemoryAccess(LAccess);
EXPECT_EQ(CallAccess, LClobber);
}
}
static BasicBlock *getBasicBlockByName(Function &F, StringRef Name) {
for (BasicBlock &BB : F)
if (BB.getName() == Name)
return &BB;
llvm_unreachable("Expected to find basic block!");
}
static Instruction *getInstructionByName(Function &F, StringRef Name) {
for (BasicBlock &BB : F)
for (Instruction &I : BB)
if (I.getName() == Name)
return &I;
llvm_unreachable("Expected to find instruction!");
}
TEST_F(MemorySSATest, TestVisitedBlocks) {
SMDiagnostic E;
auto M = parseAssemblyString(
"define void @test(i64* noalias %P, i64 %N) {\n"
"preheader.n:\n"
" br label %header.n\n"
"header.n:\n"
" %n = phi i64 [ 0, %preheader.n ], [ %inc.n, %latch.n ]\n"
" %guard.cond.i = icmp slt i64 0, %N\n"
" br i1 %guard.cond.i, label %header.i.check, label %other.i\n"
"header.i.check:\n"
" br label %preheader.i\n"
"preheader.i:\n"
" br label %header.i\n"
"header.i:\n"
" %i = phi i64 [ 0, %preheader.i ], [ %inc.i, %header.i ]\n"
" %v1 = load i64, i64* %P, align 8\n"
" %v2 = load i64, i64* %P, align 8\n"
" %inc.i = add nsw i64 %i, 1\n"
" %cmp.i = icmp slt i64 %inc.i, %N\n"
" br i1 %cmp.i, label %header.i, label %exit.i\n"
"exit.i:\n"
" br label %commonexit\n"
"other.i:\n"
" br label %commonexit\n"
"commonexit:\n"
" br label %latch.n\n"
"latch.n:\n"
" %inc.n = add nsw i64 %n, 1\n"
" %cmp.n = icmp slt i64 %inc.n, %N\n"
" br i1 %cmp.n, label %header.n, label %exit.n\n"
"exit.n:\n"
" ret void\n"
"}\n",
E, C);
ASSERT_TRUE(M);
F = M->getFunction("test");
ASSERT_TRUE(F);
setupAnalyses();
MemorySSA &MSSA = *Analyses->MSSA;
MemorySSAUpdater Updater(&MSSA);
{
// Move %v1 before the terminator of %header.i.check
BasicBlock *BB = getBasicBlockByName(*F, "header.i.check");
Instruction *LI = getInstructionByName(*F, "v1");
LI->moveBefore(BB->getTerminator());
if (MemoryUseOrDef *MUD = MSSA.getMemoryAccess(LI))
Updater.moveToPlace(MUD, BB, MemorySSA::BeforeTerminator);
// Change the termiantor of %header.i.check to `br label true, label
// %preheader.i, label %other.i`
BB->getTerminator()->eraseFromParent();
ConstantInt *BoolTrue = ConstantInt::getTrue(F->getContext());
BranchInst::Create(getBasicBlockByName(*F, "preheader.i"),
getBasicBlockByName(*F, "other.i"), BoolTrue, BB);
SmallVector<DominatorTree::UpdateType, 4> DTUpdates;
DTUpdates.push_back(DominatorTree::UpdateType(
DominatorTree::Insert, BB, getBasicBlockByName(*F, "other.i")));
Updater.applyUpdates(DTUpdates, Analyses->DT, true);
}
// After the first moveToPlace(), %other.i is in VisitedBlocks, even after
// there is a new edge to %other.i, which makes the second moveToPlace()
// traverse incorrectly.
{
// Move %v2 before the terminator of %preheader.i
BasicBlock *BB = getBasicBlockByName(*F, "preheader.i");
Instruction *LI = getInstructionByName(*F, "v2");
LI->moveBefore(BB->getTerminator());
// Check that there is no assertion of "Incomplete phi during partial
// rename"
if (MemoryUseOrDef *MUD = MSSA.getMemoryAccess(LI))
Updater.moveToPlace(MUD, BB, MemorySSA::BeforeTerminator);
}
}
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