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//===------------- llvm/unittest/CodeGen/InstrRefLDVTest.cpp --------------===//
//
// 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/CodeGen/MIRParser/MIRParser.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "../lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h"
#include "gtest/gtest.h"
using namespace llvm;
using namespace LiveDebugValues;
// Include helper functions to ease the manipulation of MachineFunctions
#include "MFCommon.inc"
class InstrRefLDVTest : public testing::Test {
public:
friend class InstrRefBasedLDV;
using MLocTransferMap = InstrRefBasedLDV::MLocTransferMap;
LLVMContext Ctx;
std::unique_ptr<Module> Mod;
std::unique_ptr<TargetMachine> Machine;
std::unique_ptr<MachineFunction> MF;
std::unique_ptr<MachineDominatorTree> DomTree;
std::unique_ptr<MachineModuleInfo> MMI;
DICompileUnit *OurCU;
DIFile *OurFile;
DISubprogram *OurFunc;
DILexicalBlock *OurBlock, *AnotherBlock;
DISubprogram *ToInlineFunc;
DILexicalBlock *ToInlineBlock;
DILocalVariable *FuncVariable;
DIBasicType *LongInt;
DIExpression *EmptyExpr;
LiveDebugValues::OverlapMap Overlaps;
DebugLoc OutermostLoc, InBlockLoc, NotNestedBlockLoc, InlinedLoc;
MachineBasicBlock *MBB0, *MBB1, *MBB2, *MBB3, *MBB4;
std::unique_ptr<InstrRefBasedLDV> LDV;
std::unique_ptr<MLocTracker> MTracker;
std::unique_ptr<VLocTracker> VTracker;
SmallString<256> MIRStr;
InstrRefLDVTest() : Ctx(), Mod(std::make_unique<Module>("beehives", Ctx)) {}
void SetUp() {
// Boilerplate that creates a MachineFunction and associated blocks.
Mod->setDataLayout("e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-"
"n8:16:32:64-S128");
Triple TargetTriple("x86_64--");
std::string Error;
const Target *T = TargetRegistry::lookupTarget("", TargetTriple, Error);
if (!T)
GTEST_SKIP();
TargetOptions Options;
Machine = std::unique_ptr<TargetMachine>(
T->createTargetMachine(Triple::normalize("x86_64--"), "", "", Options,
None, None, CodeGenOpt::Aggressive));
auto Type = FunctionType::get(Type::getVoidTy(Ctx), false);
auto F =
Function::Create(Type, GlobalValue::ExternalLinkage, "Test", &*Mod);
unsigned FunctionNum = 42;
MMI = std::make_unique<MachineModuleInfo>((LLVMTargetMachine *)&*Machine);
const TargetSubtargetInfo &STI = *Machine->getSubtargetImpl(*F);
MF = std::make_unique<MachineFunction>(*F, (LLVMTargetMachine &)*Machine,
STI, FunctionNum, *MMI);
// Create metadata: CU, subprogram, some blocks and an inline function
// scope.
DIBuilder DIB(*Mod);
OurFile = DIB.createFile("xyzzy.c", "/cave");
OurCU =
DIB.createCompileUnit(dwarf::DW_LANG_C99, OurFile, "nou", false, "", 0);
auto OurSubT = DIB.createSubroutineType(DIB.getOrCreateTypeArray(None));
OurFunc =
DIB.createFunction(OurCU, "bees", "", OurFile, 1, OurSubT, 1,
DINode::FlagZero, DISubprogram::SPFlagDefinition);
F->setSubprogram(OurFunc);
OurBlock = DIB.createLexicalBlock(OurFunc, OurFile, 2, 3);
AnotherBlock = DIB.createLexicalBlock(OurFunc, OurFile, 2, 6);
ToInlineFunc =
DIB.createFunction(OurFile, "shoes", "", OurFile, 10, OurSubT, 10,
DINode::FlagZero, DISubprogram::SPFlagDefinition);
// Make some nested scopes.
OutermostLoc = DILocation::get(Ctx, 3, 1, OurFunc);
InBlockLoc = DILocation::get(Ctx, 4, 1, OurBlock);
InlinedLoc = DILocation::get(Ctx, 10, 1, ToInlineFunc, InBlockLoc.get());
// Make a scope that isn't nested within the others.
NotNestedBlockLoc = DILocation::get(Ctx, 4, 1, AnotherBlock);
LongInt = DIB.createBasicType("long", 64, llvm::dwarf::DW_ATE_unsigned);
FuncVariable = DIB.createAutoVariable(OurFunc, "lala", OurFile, 1, LongInt);
EmptyExpr = DIExpression::get(Ctx, {});
DIB.finalize();
}
Register getRegByName(const char *WantedName) {
auto *TRI = MF->getRegInfo().getTargetRegisterInfo();
// Slow, but works.
for (unsigned int I = 1; I < TRI->getNumRegs(); ++I) {
const char *Name = TRI->getName(I);
if (strcmp(WantedName, Name) == 0)
return I;
}
// If this ever fails, something is very wrong with this unit test.
llvm_unreachable("Can't find register by name");
}
InstrRefBasedLDV *setupLDVObj(MachineFunction *MF) {
// Create a new LDV object, and plug some relevant object ptrs into it.
LDV = std::make_unique<InstrRefBasedLDV>();
const TargetSubtargetInfo &STI = MF->getSubtarget();
LDV->TII = STI.getInstrInfo();
LDV->TRI = STI.getRegisterInfo();
LDV->TFI = STI.getFrameLowering();
LDV->MFI = &MF->getFrameInfo();
LDV->MRI = &MF->getRegInfo();
DomTree = std::make_unique<MachineDominatorTree>(*MF);
LDV->DomTree = &*DomTree;
// Future work: unit tests for mtracker / vtracker / ttracker.
// Setup things like the artifical block map, and BlockNo <=> RPO Order
// mappings.
LDV->initialSetup(*MF);
LDV->LS.initialize(*MF);
addMTracker(MF);
return &*LDV;
}
void addMTracker(MachineFunction *MF) {
ASSERT_TRUE(LDV);
// Add a machine-location-tracking object to LDV. Don't initialize any
// register locations within it though.
const TargetSubtargetInfo &STI = MF->getSubtarget();
MTracker = std::make_unique<MLocTracker>(
*MF, *LDV->TII, *LDV->TRI, *STI.getTargetLowering());
LDV->MTracker = &*MTracker;
}
void addVTracker() {
ASSERT_TRUE(LDV);
VTracker = std::make_unique<VLocTracker>(Overlaps, EmptyExpr);
LDV->VTracker = &*VTracker;
}
// Some routines for bouncing into LDV,
void buildMLocValueMap(ValueIDNum **MInLocs, ValueIDNum **MOutLocs,
SmallVectorImpl<MLocTransferMap> &MLocTransfer) {
LDV->buildMLocValueMap(*MF, MInLocs, MOutLocs, MLocTransfer);
}
void placeMLocPHIs(MachineFunction &MF,
SmallPtrSetImpl<MachineBasicBlock *> &AllBlocks,
ValueIDNum **MInLocs,
SmallVectorImpl<MLocTransferMap> &MLocTransfer) {
LDV->placeMLocPHIs(MF, AllBlocks, MInLocs, MLocTransfer);
}
Optional<ValueIDNum>
pickVPHILoc(const MachineBasicBlock &MBB, const DebugVariable &Var,
const InstrRefBasedLDV::LiveIdxT &LiveOuts, ValueIDNum **MOutLocs,
const SmallVectorImpl<const MachineBasicBlock *> &BlockOrders) {
return LDV->pickVPHILoc(MBB, Var, LiveOuts, MOutLocs, BlockOrders);
}
bool vlocJoin(MachineBasicBlock &MBB, InstrRefBasedLDV::LiveIdxT &VLOCOutLocs,
SmallPtrSet<const MachineBasicBlock *, 8> &BlocksToExplore,
DbgValue &InLoc) {
return LDV->vlocJoin(MBB, VLOCOutLocs, BlocksToExplore, InLoc);
}
void buildVLocValueMap(const DILocation *DILoc,
const SmallSet<DebugVariable, 4> &VarsWeCareAbout,
SmallPtrSetImpl<MachineBasicBlock *> &AssignBlocks,
InstrRefBasedLDV::LiveInsT &Output, ValueIDNum **MOutLocs,
ValueIDNum **MInLocs,
SmallVectorImpl<VLocTracker> &AllTheVLocs) {
LDV->buildVLocValueMap(DILoc, VarsWeCareAbout, AssignBlocks, Output,
MOutLocs, MInLocs, AllTheVLocs);
}
void initValueArray(ValueIDNum **Nums, unsigned Blks, unsigned Locs) {
for (unsigned int I = 0; I < Blks; ++I)
for (unsigned int J = 0; J < Locs; ++J)
Nums[I][J] = ValueIDNum::EmptyValue;
}
void setupSingleBlock() {
// Add an entry block with nothing but 'ret void' in it.
Function &F = const_cast<llvm::Function &>(MF->getFunction());
auto *BB0 = BasicBlock::Create(Ctx, "entry", &F);
IRBuilder<> IRB(BB0);
IRB.CreateRetVoid();
MBB0 = MF->CreateMachineBasicBlock(BB0);
MF->insert(MF->end(), MBB0);
MF->RenumberBlocks();
setupLDVObj(&*MF);
}
void setupDiamondBlocks() {
// entry
// / \
// br1 br2
// \ /
// ret
llvm::Function &F = const_cast<llvm::Function &>(MF->getFunction());
auto *BB0 = BasicBlock::Create(Ctx, "a", &F);
auto *BB1 = BasicBlock::Create(Ctx, "b", &F);
auto *BB2 = BasicBlock::Create(Ctx, "c", &F);
auto *BB3 = BasicBlock::Create(Ctx, "d", &F);
IRBuilder<> IRB0(BB0), IRB1(BB1), IRB2(BB2), IRB3(BB3);
IRB0.CreateBr(BB1);
IRB1.CreateBr(BB2);
IRB2.CreateBr(BB3);
IRB3.CreateRetVoid();
MBB0 = MF->CreateMachineBasicBlock(BB0);
MF->insert(MF->end(), MBB0);
MBB1 = MF->CreateMachineBasicBlock(BB1);
MF->insert(MF->end(), MBB1);
MBB2 = MF->CreateMachineBasicBlock(BB2);
MF->insert(MF->end(), MBB2);
MBB3 = MF->CreateMachineBasicBlock(BB3);
MF->insert(MF->end(), MBB3);
MBB0->addSuccessor(MBB1);
MBB0->addSuccessor(MBB2);
MBB1->addSuccessor(MBB3);
MBB2->addSuccessor(MBB3);
MF->RenumberBlocks();
setupLDVObj(&*MF);
}
void setupSimpleLoop() {
// entry
// |
// |/-----\
// loopblk |
// |\-----/
// |
// ret
llvm::Function &F = const_cast<llvm::Function &>(MF->getFunction());
auto *BB0 = BasicBlock::Create(Ctx, "entry", &F);
auto *BB1 = BasicBlock::Create(Ctx, "loop", &F);
auto *BB2 = BasicBlock::Create(Ctx, "ret", &F);
IRBuilder<> IRB0(BB0), IRB1(BB1), IRB2(BB2);
IRB0.CreateBr(BB1);
IRB1.CreateBr(BB2);
IRB2.CreateRetVoid();
MBB0 = MF->CreateMachineBasicBlock(BB0);
MF->insert(MF->end(), MBB0);
MBB1 = MF->CreateMachineBasicBlock(BB1);
MF->insert(MF->end(), MBB1);
MBB2 = MF->CreateMachineBasicBlock(BB2);
MF->insert(MF->end(), MBB2);
MBB0->addSuccessor(MBB1);
MBB1->addSuccessor(MBB2);
MBB1->addSuccessor(MBB1);
MF->RenumberBlocks();
setupLDVObj(&*MF);
}
void setupNestedLoops() {
// entry
// |
// loop1
// ^\
// | \ /-\
// | loop2 |
// | / \-/
// ^ /
// join
// |
// ret
llvm::Function &F = const_cast<llvm::Function &>(MF->getFunction());
auto *BB0 = BasicBlock::Create(Ctx, "entry", &F);
auto *BB1 = BasicBlock::Create(Ctx, "loop1", &F);
auto *BB2 = BasicBlock::Create(Ctx, "loop2", &F);
auto *BB3 = BasicBlock::Create(Ctx, "join", &F);
auto *BB4 = BasicBlock::Create(Ctx, "ret", &F);
IRBuilder<> IRB0(BB0), IRB1(BB1), IRB2(BB2), IRB3(BB3), IRB4(BB4);
IRB0.CreateBr(BB1);
IRB1.CreateBr(BB2);
IRB2.CreateBr(BB3);
IRB3.CreateBr(BB4);
IRB4.CreateRetVoid();
MBB0 = MF->CreateMachineBasicBlock(BB0);
MF->insert(MF->end(), MBB0);
MBB1 = MF->CreateMachineBasicBlock(BB1);
MF->insert(MF->end(), MBB1);
MBB2 = MF->CreateMachineBasicBlock(BB2);
MF->insert(MF->end(), MBB2);
MBB3 = MF->CreateMachineBasicBlock(BB3);
MF->insert(MF->end(), MBB3);
MBB4 = MF->CreateMachineBasicBlock(BB4);
MF->insert(MF->end(), MBB4);
MBB0->addSuccessor(MBB1);
MBB1->addSuccessor(MBB2);
MBB2->addSuccessor(MBB2);
MBB2->addSuccessor(MBB3);
MBB3->addSuccessor(MBB1);
MBB3->addSuccessor(MBB4);
MF->RenumberBlocks();
setupLDVObj(&*MF);
}
void setupNoDominatingLoop() {
// entry
// / \
// / \
// / \
// head1 head2
// ^ \ / ^
// ^ \ / ^
// \-joinblk -/
// |
// ret
llvm::Function &F = const_cast<llvm::Function &>(MF->getFunction());
auto *BB0 = BasicBlock::Create(Ctx, "entry", &F);
auto *BB1 = BasicBlock::Create(Ctx, "head1", &F);
auto *BB2 = BasicBlock::Create(Ctx, "head2", &F);
auto *BB3 = BasicBlock::Create(Ctx, "joinblk", &F);
auto *BB4 = BasicBlock::Create(Ctx, "ret", &F);
IRBuilder<> IRB0(BB0), IRB1(BB1), IRB2(BB2), IRB3(BB3), IRB4(BB4);
IRB0.CreateBr(BB1);
IRB1.CreateBr(BB2);
IRB2.CreateBr(BB3);
IRB3.CreateBr(BB4);
IRB4.CreateRetVoid();
MBB0 = MF->CreateMachineBasicBlock(BB0);
MF->insert(MF->end(), MBB0);
MBB1 = MF->CreateMachineBasicBlock(BB1);
MF->insert(MF->end(), MBB1);
MBB2 = MF->CreateMachineBasicBlock(BB2);
MF->insert(MF->end(), MBB2);
MBB3 = MF->CreateMachineBasicBlock(BB3);
MF->insert(MF->end(), MBB3);
MBB4 = MF->CreateMachineBasicBlock(BB4);
MF->insert(MF->end(), MBB4);
MBB0->addSuccessor(MBB1);
MBB0->addSuccessor(MBB2);
MBB1->addSuccessor(MBB3);
MBB2->addSuccessor(MBB3);
MBB3->addSuccessor(MBB1);
MBB3->addSuccessor(MBB2);
MBB3->addSuccessor(MBB4);
MF->RenumberBlocks();
setupLDVObj(&*MF);
}
void setupBadlyNestedLoops() {
// entry
// |
// loop1 -o
// | ^
// | ^
// loop2 -o
// | ^
// | ^
// loop3 -o
// |
// ret
//
// NB: the loop blocks self-loop, which is a bit too fiddly to draw on
// accurately.
llvm::Function &F = const_cast<llvm::Function &>(MF->getFunction());
auto *BB0 = BasicBlock::Create(Ctx, "entry", &F);
auto *BB1 = BasicBlock::Create(Ctx, "loop1", &F);
auto *BB2 = BasicBlock::Create(Ctx, "loop2", &F);
auto *BB3 = BasicBlock::Create(Ctx, "loop3", &F);
auto *BB4 = BasicBlock::Create(Ctx, "ret", &F);
IRBuilder<> IRB0(BB0), IRB1(BB1), IRB2(BB2), IRB3(BB3), IRB4(BB4);
IRB0.CreateBr(BB1);
IRB1.CreateBr(BB2);
IRB2.CreateBr(BB3);
IRB3.CreateBr(BB4);
IRB4.CreateRetVoid();
MBB0 = MF->CreateMachineBasicBlock(BB0);
MF->insert(MF->end(), MBB0);
MBB1 = MF->CreateMachineBasicBlock(BB1);
MF->insert(MF->end(), MBB1);
MBB2 = MF->CreateMachineBasicBlock(BB2);
MF->insert(MF->end(), MBB2);
MBB3 = MF->CreateMachineBasicBlock(BB3);
MF->insert(MF->end(), MBB3);
MBB4 = MF->CreateMachineBasicBlock(BB4);
MF->insert(MF->end(), MBB4);
MBB0->addSuccessor(MBB1);
MBB1->addSuccessor(MBB1);
MBB1->addSuccessor(MBB2);
MBB2->addSuccessor(MBB1);
MBB2->addSuccessor(MBB2);
MBB2->addSuccessor(MBB3);
MBB3->addSuccessor(MBB2);
MBB3->addSuccessor(MBB3);
MBB3->addSuccessor(MBB4);
MF->RenumberBlocks();
setupLDVObj(&*MF);
}
MachineFunction *readMIRBlock(const char *Input) {
MIRStr.clear();
StringRef S = Twine(Twine(R"MIR(
--- |
target triple = "x86_64-unknown-linux-gnu"
define void @test() { ret void }
...
---
name: test
tracksRegLiveness: true
stack:
- { id: 0, name: '', type: spill-slot, offset: -16, size: 8, alignment: 8,
stack-id: default, callee-saved-register: '', callee-saved-restored: true,
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
body: |
bb.0:
liveins: $rdi, $rsi
)MIR") + Twine(Input) + Twine("...\n"))
.toNullTerminatedStringRef(MIRStr);
;
// Clear the "test" function from MMI if it's still present.
if (Function *Fn = Mod->getFunction("test"))
MMI->deleteMachineFunctionFor(*Fn);
auto MemBuf = MemoryBuffer::getMemBuffer(S, "<input>");
auto MIRParse = createMIRParser(std::move(MemBuf), Ctx);
Mod = MIRParse->parseIRModule();
assert(Mod);
Mod->setDataLayout("e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-"
"n8:16:32:64-S128");
bool Result = MIRParse->parseMachineFunctions(*Mod, *MMI);
assert(!Result && "Failed to parse unit test machine function?");
(void)Result;
Function *Fn = Mod->getFunction("test");
assert(Fn && "Failed to parse a unit test module string?");
Fn->setSubprogram(OurFunc);
return MMI->getMachineFunction(*Fn);
}
void
produceMLocTransferFunction(MachineFunction &MF,
SmallVectorImpl<MLocTransferMap> &MLocTransfer,
unsigned MaxNumBlocks) {
LDV->produceMLocTransferFunction(MF, MLocTransfer, MaxNumBlocks);
}
};
TEST_F(InstrRefLDVTest, MTransferDefs) {
MachineFunction *MF = readMIRBlock(
" $rax = MOV64ri 0\n"
" RET64 $rax\n");
setupLDVObj(MF);
// We should start with only SP tracked.
EXPECT_TRUE(MTracker->getNumLocs() == 1);
SmallVector<MLocTransferMap, 1> TransferMap;
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
// Code contains only one register write: that should assign to each of the
// aliasing registers. Test that all of them get locations, and have a
// corresponding def at the first instr in the function.
const char *RegNames[] = {"RAX", "HAX", "EAX", "AX", "AH", "AL"};
EXPECT_TRUE(MTracker->getNumLocs() == 7);
for (const char *RegName : RegNames) {
Register R = getRegByName(RegName);
ASSERT_TRUE(MTracker->isRegisterTracked(R));
LocIdx L = MTracker->getRegMLoc(R);
ValueIDNum V = MTracker->readReg(R);
// Value of this register should be: block zero, instruction 1, and the
// location it's defined in is itself.
ValueIDNum ToCmp(0, 1, L);
EXPECT_EQ(V, ToCmp);
}
// Do the same again, but with an aliasing write. This should write to all
// the same registers again, except $ah and $hax (the upper 8 bits of $ax
// and 32 bits of $rax resp.).
MF = readMIRBlock(
" $rax = MOV64ri 0\n"
" $al = MOV8ri 0\n"
" RET64 $rax\n");
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
auto TestRegSetSite = [&](const char *Name, unsigned InstrNum) {
Register R = getRegByName(Name);
ASSERT_TRUE(MTracker->isRegisterTracked(R));
LocIdx L = MTracker->getRegMLoc(R);
ValueIDNum V = MTracker->readMLoc(L);
ValueIDNum ToCmp(0, InstrNum, L);
EXPECT_EQ(V, ToCmp);
};
TestRegSetSite("AL", 2);
TestRegSetSite("AH", 1);
TestRegSetSite("AX", 2);
TestRegSetSite("EAX", 2);
TestRegSetSite("HAX", 1);
TestRegSetSite("RAX", 2);
// This call should:
// * Def rax via the implicit-def,
// * Clobber rsi/rdi and all their subregs, via the register mask
// * Same for rcx, despite it not being a use in the instr, it's in the mask
// * NOT clobber $rsp / $esp $ sp, LiveDebugValues deliberately ignores
// these.
// * NOT clobber $rbx, because it's non-volatile
// * Not track every other register in the machine, only those needed.
MF = readMIRBlock(
" $rax = MOV64ri 0\n" // instr 1
" $rbx = MOV64ri 0\n" // instr 2
" $rcx = MOV64ri 0\n" // instr 3
" $rdi = MOV64ri 0\n" // instr 4
" $rsi = MOV64ri 0\n" // instr 5
" CALL64r $rax, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, implicit $rsi, implicit-def $rsp, implicit-def $ssp, implicit-def $rax, implicit-def $esp, implicit-def $sp\n\n\n\n" // instr 6
" RET64 $rax\n"); // instr 7
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
const char *RegsSetInCall[] = {"AL", "AH", "AX", "EAX", "HAX", "RAX",
"DIL", "DIH", "DI", "EDI", "HDI", "RDI",
"SIL", "SIH", "SI", "ESI", "HSI", "RSI",
"CL", "CH", "CX", "ECX", "HCX", "RCX"};
for (const char *RegSetInCall : RegsSetInCall)
TestRegSetSite(RegSetInCall, 6);
const char *RegsLeftAlone[] = {"BL", "BH", "BX", "EBX", "HBX", "RBX"};
for (const char *RegLeftAlone : RegsLeftAlone)
TestRegSetSite(RegLeftAlone, 2);
// Stack pointer should be the live-in to the function, instruction zero.
TestRegSetSite("RSP", 0);
// These stack regs should not be tracked either. Nor the (fake) subregs.
EXPECT_FALSE(MTracker->isRegisterTracked(getRegByName("ESP")));
EXPECT_FALSE(MTracker->isRegisterTracked(getRegByName("SP")));
EXPECT_FALSE(MTracker->isRegisterTracked(getRegByName("SPL")));
EXPECT_FALSE(MTracker->isRegisterTracked(getRegByName("SPH")));
EXPECT_FALSE(MTracker->isRegisterTracked(getRegByName("HSP")));
// Should only be tracking: 6 x {A, B, C, DI, SI} registers = 30,
// Plus RSP, SSP = 32.
EXPECT_EQ(32u, MTracker->getNumLocs());
// When we DBG_PHI something, we should track all its subregs.
MF = readMIRBlock(
" DBG_PHI $rdi, 0\n"
" RET64\n");
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
// All DI regs and RSP tracked.
EXPECT_EQ(7u, MTracker->getNumLocs());
// All the DI registers should have block live-in values, i.e. the argument
// to the function.
const char *DIRegs[] = {"DIL", "DIH", "DI", "EDI", "HDI", "RDI"};
for (const char *DIReg : DIRegs)
TestRegSetSite(DIReg, 0);
}
TEST_F(InstrRefLDVTest, MTransferMeta) {
// Meta instructions should not have any effect on register values.
SmallVector<MLocTransferMap, 1> TransferMap;
MachineFunction *MF = readMIRBlock(
" $rax = MOV64ri 0\n"
" $rax = IMPLICIT_DEF\n"
" $rax = KILL killed $rax\n"
" RET64 $rax\n");
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
LocIdx RaxLoc = MTracker->getRegMLoc(getRegByName("RAX"));
ValueIDNum V = MTracker->readMLoc(RaxLoc);
// Def of rax should be from instruction 1, i.e., unmodified.
ValueIDNum Cmp(0, 1, RaxLoc);
EXPECT_EQ(Cmp, V);
}
TEST_F(InstrRefLDVTest, MTransferCopies) {
SmallVector<MLocTransferMap, 1> TransferMap;
// This memory spill should be recognised, and a spill slot created.
MachineFunction *MF = readMIRBlock(
" $rax = MOV64ri 0\n"
" MOV64mr $rsp, 1, $noreg, 16, $noreg, $rax :: (store 8 into %stack.0)\n"
" RET64 $rax\n");
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
// Check that the spill location contains the value defined in rax by
// instruction 1. The MIR header says -16 offset, but it's stored as -8;
// it's not completely clear why, but here we only care about correctly
// identifying the slot, not that all the surrounding data is correct.
SpillLoc L = {getRegByName("RSP"), StackOffset::getFixed(-8)};
SpillLocationNo SpillNo = MTracker->getOrTrackSpillLoc(L);
unsigned SpillLocID = MTracker->getLocID(SpillNo, {64, 0});
LocIdx SpillLoc = MTracker->getSpillMLoc(SpillLocID);
ValueIDNum V = MTracker->readMLoc(SpillLoc);
Register RAX = getRegByName("RAX");
LocIdx RaxLoc = MTracker->getRegMLoc(RAX);
ValueIDNum Cmp(0, 1, RaxLoc);
EXPECT_EQ(V, Cmp);
// A spill and restore should be recognised.
MF = readMIRBlock(
" $rax = MOV64ri 0\n"
" MOV64mr $rsp, 1, $noreg, 16, $noreg, $rax :: (store 8 into %stack.0)\n"
" $rbx = MOV64rm $rsp, 1, $noreg, 0, $noreg :: (load 8 from %stack.0)\n"
" RET64\n");
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
// Test that rbx contains rax from instruction 1.
RAX = getRegByName("RAX");
RaxLoc = MTracker->getRegMLoc(RAX);
Register RBX = getRegByName("RBX");
LocIdx RbxLoc = MTracker->getRegMLoc(RBX);
Cmp = ValueIDNum(0, 1, RaxLoc);
ValueIDNum RbxVal = MTracker->readMLoc(RbxLoc);
EXPECT_EQ(RbxVal, Cmp);
// Testing that all the subregisters are transferred happens in
// MTransferSubregSpills.
// Copies and x86 movs should be recognised and honoured. In addition, all
// of the subregisters should be copied across too.
MF = readMIRBlock(
" $rax = MOV64ri 0\n"
" $rcx = COPY $rax\n"
" $rbx = MOV64rr $rcx\n"
" RET64\n");
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
const char *ARegs[] = {"AL", "AH", "AX", "EAX", "HAX", "RAX"};
const char *BRegs[] = {"BL", "BH", "BX", "EBX", "HBX", "RBX"};
const char *CRegs[] = {"CL", "CH", "CX", "ECX", "HCX", "RCX"};
auto CheckReg = [&](unsigned int I) {
LocIdx A = MTracker->getRegMLoc(getRegByName(ARegs[I]));
LocIdx B = MTracker->getRegMLoc(getRegByName(BRegs[I]));
LocIdx C = MTracker->getRegMLoc(getRegByName(CRegs[I]));
ValueIDNum ARefVal(0, 1, A);
ValueIDNum AVal = MTracker->readMLoc(A);
ValueIDNum BVal = MTracker->readMLoc(B);
ValueIDNum CVal = MTracker->readMLoc(C);
EXPECT_EQ(ARefVal, AVal);
EXPECT_EQ(ARefVal, BVal);
EXPECT_EQ(ARefVal, CVal);
};
for (unsigned int I = 0; I < 6; ++I)
CheckReg(I);
// When we copy to a subregister, the super-register should be def'd too: it's
// value will have changed.
MF = readMIRBlock(
" $rax = MOV64ri 0\n"
" $ecx = COPY $eax\n"
" RET64\n");
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
// First four regs [al, ah, ax, eax] should be copied to *cx.
for (unsigned int I = 0; I < 4; ++I) {
LocIdx A = MTracker->getRegMLoc(getRegByName(ARegs[I]));
LocIdx C = MTracker->getRegMLoc(getRegByName(CRegs[I]));
ValueIDNum ARefVal(0, 1, A);
ValueIDNum AVal = MTracker->readMLoc(A);
ValueIDNum CVal = MTracker->readMLoc(C);
EXPECT_EQ(ARefVal, AVal);
EXPECT_EQ(ARefVal, CVal);
}
// But rcx should contain a value defined by the COPY.
LocIdx RcxLoc = MTracker->getRegMLoc(getRegByName("RCX"));
ValueIDNum RcxVal = MTracker->readMLoc(RcxLoc);
ValueIDNum RcxDefVal(0, 2, RcxLoc); // instr 2 -> the copy
EXPECT_EQ(RcxVal, RcxDefVal);
}
TEST_F(InstrRefLDVTest, MTransferSubregSpills) {
SmallVector<MLocTransferMap, 1> TransferMap;
MachineFunction *MF = readMIRBlock(
" $rax = MOV64ri 0\n"
" MOV64mr $rsp, 1, $noreg, 16, $noreg, $rax :: (store 8 into %stack.0)\n"
" $rbx = MOV64rm $rsp, 1, $noreg, 0, $noreg :: (load 8 from %stack.0)\n"
" RET64\n");
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
// Check that all the subregs of rax and rbx contain the same values. One
// should completely transfer to the other.
const char *ARegs[] = {"AL", "AH", "AX", "EAX", "HAX", "RAX"};
const char *BRegs[] = {"BL", "BH", "BX", "EBX", "HBX", "RBX"};
for (unsigned int I = 0; I < 6; ++I) {
LocIdx A = MTracker->getRegMLoc(getRegByName(ARegs[I]));
LocIdx B = MTracker->getRegMLoc(getRegByName(BRegs[I]));
EXPECT_EQ(MTracker->readMLoc(A), MTracker->readMLoc(B));
}
// Explicitly check what's in the different subreg slots, on the stack.
// Pair up subreg idx fields with the corresponding subregister in $rax.
MLocTracker::StackSlotPos SubRegIdxes[] = {{8, 0}, {8, 8}, {16, 0}, {32, 0}, {64, 0}};
const char *SubRegNames[] = {"AL", "AH", "AX", "EAX", "RAX"};
for (unsigned int I = 0; I < 5; ++I) {
// Value number where it's defined,
LocIdx RegLoc = MTracker->getRegMLoc(getRegByName(SubRegNames[I]));
ValueIDNum DefNum(0, 1, RegLoc);
// Read the corresponding subreg field from the stack.
SpillLoc L = {getRegByName("RSP"), StackOffset::getFixed(-8)};
SpillLocationNo SpillNo = MTracker->getOrTrackSpillLoc(L);
unsigned SpillID = MTracker->getLocID(SpillNo, SubRegIdxes[I]);
LocIdx SpillLoc = MTracker->getSpillMLoc(SpillID);
ValueIDNum SpillValue = MTracker->readMLoc(SpillLoc);
EXPECT_EQ(DefNum, SpillValue);
}
// If we have exactly the same code, but we write $eax to the stack slot after
// $rax, then we should still have exactly the same output in the lower five
// subregisters. Storing $eax to the start of the slot will overwrite with the
// same values. $rax, as an aliasing register, should be reset to something
// else by that write.
// In theory, we could try and recognise that we're writing the _same_ values
// to the stack again, and so $rax doesn't need to be reset to something else.
// It seems vanishingly unlikely that LLVM would generate such code though,
// so the benefits would be small.
MF = readMIRBlock(
" $rax = MOV64ri 0\n"
" MOV64mr $rsp, 1, $noreg, 16, $noreg, $rax :: (store 8 into %stack.0)\n"
" MOV32mr $rsp, 1, $noreg, 16, $noreg, $eax :: (store 4 into %stack.0)\n"
" $rbx = MOV64rm $rsp, 1, $noreg, 0, $noreg :: (load 8 from %stack.0)\n"
" RET64\n");
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
// Check lower five registers up to and include $eax == $ebx,
for (unsigned int I = 0; I < 5; ++I) {
LocIdx A = MTracker->getRegMLoc(getRegByName(ARegs[I]));
LocIdx B = MTracker->getRegMLoc(getRegByName(BRegs[I]));
EXPECT_EQ(MTracker->readMLoc(A), MTracker->readMLoc(B));
}
// $rbx should contain something else; today it's a def at the spill point
// of the 4 byte value.
SpillLoc L = {getRegByName("RSP"), StackOffset::getFixed(-8)};
SpillLocationNo SpillNo = MTracker->getOrTrackSpillLoc(L);
unsigned SpillID = MTracker->getLocID(SpillNo, {64, 0});
LocIdx Spill64Loc = MTracker->getSpillMLoc(SpillID);
ValueIDNum DefAtSpill64(0, 3, Spill64Loc);
LocIdx RbxLoc = MTracker->getRegMLoc(getRegByName("RBX"));
EXPECT_EQ(MTracker->readMLoc(RbxLoc), DefAtSpill64);
// Same again, test that the lower four subreg slots on the stack are the
// value defined by $rax in instruction 1.
for (unsigned int I = 0; I < 4; ++I) {
// Value number where it's defined,
LocIdx RegLoc = MTracker->getRegMLoc(getRegByName(SubRegNames[I]));
ValueIDNum DefNum(0, 1, RegLoc);
// Read the corresponding subreg field from the stack.
SpillNo = MTracker->getOrTrackSpillLoc(L);
SpillID = MTracker->getLocID(SpillNo, SubRegIdxes[I]);
LocIdx SpillLoc = MTracker->getSpillMLoc(SpillID);
ValueIDNum SpillValue = MTracker->readMLoc(SpillLoc);
EXPECT_EQ(DefNum, SpillValue);
}
// Stack slot for $rax should be a different value, today it's EmptyValue.
ValueIDNum SpillValue = MTracker->readMLoc(Spill64Loc);
EXPECT_EQ(SpillValue, DefAtSpill64);
// If we write something to the stack, then over-write with some register
// from a completely different hierarchy, none of the "old" values should be
// readable.
// NB: slight hack, store 16 in to a 8 byte stack slot.
MF = readMIRBlock(
" $rax = MOV64ri 0\n"
" MOV64mr $rsp, 1, $noreg, 16, $noreg, $rax :: (store 8 into %stack.0)\n"
" $xmm0 = IMPLICIT_DEF\n"
" MOVUPDmr $rsp, 1, $noreg, 16, $noreg, killed $xmm0 :: (store (s128) into %stack.0)\n"
" $rbx = MOV64rm $rsp, 1, $noreg, 0, $noreg :: (load 8 from %stack.0)\n"
" RET64\n");
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
for (unsigned int I = 0; I < 5; ++I) {
// Read subreg fields from the stack.
SpillLocationNo SpillNo = MTracker->getOrTrackSpillLoc(L);
unsigned SpillID = MTracker->getLocID(SpillNo, SubRegIdxes[I]);
LocIdx SpillLoc = MTracker->getSpillMLoc(SpillID);
ValueIDNum SpillValue = MTracker->readMLoc(SpillLoc);
// Value should be defined by the spill-to-xmm0 instr, get value of a def
// at the point of the spill.
ValueIDNum SpillDef(0, 4, SpillLoc);
EXPECT_EQ(SpillValue, SpillDef);
}
// Read xmm0's position and ensure it has a value. Should be the live-in
// value to the block, as IMPLICIT_DEF isn't a real def.
SpillNo = MTracker->getOrTrackSpillLoc(L);
SpillID = MTracker->getLocID(SpillNo, {128, 0});
LocIdx Spill128Loc = MTracker->getSpillMLoc(SpillID);
SpillValue = MTracker->readMLoc(Spill128Loc);
Register XMM0 = getRegByName("XMM0");
LocIdx Xmm0Loc = MTracker->getRegMLoc(XMM0);
EXPECT_EQ(ValueIDNum(0, 0, Xmm0Loc), SpillValue);
// What happens if we spill ah to the stack, then load al? It should find
// the same value.
MF = readMIRBlock(
" $rax = MOV64ri 0\n"
" MOV8mr $rsp, 1, $noreg, 16, $noreg, $ah :: (store 1 into %stack.0)\n"
" $al = MOV8rm $rsp, 1, $noreg, 0, $noreg :: (load 1 from %stack.0)\n"
" RET64\n");
setupLDVObj(MF);
TransferMap.clear();
TransferMap.resize(1);
produceMLocTransferFunction(*MF, TransferMap, 1);
Register AL = getRegByName("AL");
Register AH = getRegByName("AH");
LocIdx AlLoc = MTracker->getRegMLoc(AL);
LocIdx AhLoc = MTracker->getRegMLoc(AH);
ValueIDNum AHDef(0, 1, AhLoc);
ValueIDNum ALValue = MTracker->readMLoc(AlLoc);
EXPECT_EQ(ALValue, AHDef);
}
TEST_F(InstrRefLDVTest, MLocSingleBlock) {
// Test some very simple properties about interpreting the transfer function.
setupSingleBlock();
// We should start with a single location, the stack pointer.
ASSERT_TRUE(MTracker->getNumLocs() == 1);
LocIdx RspLoc(0);
// Set up live-in and live-out tables for this function: two locations (we
// add one later) in a single block.
ValueIDNum InLocs[2], OutLocs[2];
ValueIDNum *InLocsPtr[1] = {&InLocs[0]};
ValueIDNum *OutLocsPtr[1] = {&OutLocs[0]};
// Transfer function: nothing.
SmallVector<MLocTransferMap, 1> TransferFunc;
TransferFunc.resize(1);
// Try and build value maps...
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
// The result should be that RSP is marked as a live-in-PHI -- this represents
// an argument. And as there's no transfer function, the block live-out should
// be the same.
EXPECT_EQ(InLocs[0], ValueIDNum(0, 0, RspLoc));
EXPECT_EQ(OutLocs[0], ValueIDNum(0, 0, RspLoc));
// Try again, this time initialising the in-locs to be defined by an
// instruction. The entry block should always be re-assigned to be the
// arguments.
initValueArray(InLocsPtr, 1, 2);
initValueArray(OutLocsPtr, 1, 2);
InLocs[0] = ValueIDNum(0, 1, RspLoc);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0], ValueIDNum(0, 0, RspLoc));
EXPECT_EQ(OutLocs[0], ValueIDNum(0, 0, RspLoc));
// Now insert something into the transfer function to assign to the single
// machine location.
TransferFunc[0].insert({RspLoc, ValueIDNum(0, 1, RspLoc)});
initValueArray(InLocsPtr, 1, 2);
initValueArray(OutLocsPtr, 1, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0], ValueIDNum(0, 0, RspLoc));
EXPECT_EQ(OutLocs[0], ValueIDNum(0, 1, RspLoc));
TransferFunc[0].clear();
// Add a new register to be tracked, and insert it into the transfer function
// as a copy. The output of $rax should be the live-in value of $rsp.
Register RAX = getRegByName("RAX");
LocIdx RaxLoc = MTracker->lookupOrTrackRegister(RAX);
TransferFunc[0].insert({RspLoc, ValueIDNum(0, 1, RspLoc)});
TransferFunc[0].insert({RaxLoc, ValueIDNum(0, 0, RspLoc)});
initValueArray(InLocsPtr, 1, 2);
initValueArray(OutLocsPtr, 1, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0], ValueIDNum(0, 0, RspLoc));
EXPECT_EQ(InLocs[1], ValueIDNum(0, 0, RaxLoc));
EXPECT_EQ(OutLocs[0], ValueIDNum(0, 1, RspLoc));
EXPECT_EQ(OutLocs[1], ValueIDNum(0, 0, RspLoc)); // Rax contains RspLoc.
TransferFunc[0].clear();
}
TEST_F(InstrRefLDVTest, MLocDiamondBlocks) {
// Test that information flows from the entry block to two successors.
// entry
// / \
// br1 br2
// \ /
// ret
setupDiamondBlocks();
ASSERT_TRUE(MTracker->getNumLocs() == 1);
LocIdx RspLoc(0);
Register RAX = getRegByName("RAX");
LocIdx RaxLoc = MTracker->lookupOrTrackRegister(RAX);
ValueIDNum InLocs[4][2], OutLocs[4][2];
ValueIDNum *InLocsPtr[4] = {InLocs[0], InLocs[1], InLocs[2], InLocs[3]};
ValueIDNum *OutLocsPtr[4] = {OutLocs[0], OutLocs[1], OutLocs[2], OutLocs[3]};
// Transfer function: start with nothing.
SmallVector<MLocTransferMap, 1> TransferFunc;
TransferFunc.resize(4);
// Name some values.
unsigned EntryBlk = 0, BrBlk1 = 1, BrBlk2 = 2, RetBlk = 3;
ValueIDNum LiveInRsp(EntryBlk, 0, RspLoc);
ValueIDNum RspDefInBlk0(EntryBlk, 1, RspLoc);
ValueIDNum RspDefInBlk1(BrBlk1, 1, RspLoc);
ValueIDNum RspDefInBlk2(BrBlk2, 1, RspLoc);
ValueIDNum RspPHIInBlk3(RetBlk, 0, RspLoc);
ValueIDNum RaxLiveInBlk1(BrBlk1, 0, RaxLoc);
ValueIDNum RaxLiveInBlk2(BrBlk2, 0, RaxLoc);
// With no transfer function, the live-in values to the entry block should
// propagate to all live-outs and the live-ins to the two successor blocks.
// IN ADDITION: this checks that the exit block doesn't get a PHI put in it.
initValueArray(InLocsPtr, 4, 2);
initValueArray(OutLocsPtr, 4, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], LiveInRsp);
EXPECT_EQ(InLocs[2][0], LiveInRsp);
EXPECT_EQ(InLocs[3][0], LiveInRsp);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], LiveInRsp);
EXPECT_EQ(OutLocs[2][0], LiveInRsp);
EXPECT_EQ(OutLocs[3][0], LiveInRsp);
// (Skipped writing out locations for $rax).
// Check that a def of $rsp in the entry block will likewise reach all the
// successors.
TransferFunc[0].insert({RspLoc, RspDefInBlk0});
initValueArray(InLocsPtr, 4, 2);
initValueArray(OutLocsPtr, 4, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspDefInBlk0);
EXPECT_EQ(InLocs[2][0], RspDefInBlk0);
EXPECT_EQ(InLocs[3][0], RspDefInBlk0);
EXPECT_EQ(OutLocs[0][0], RspDefInBlk0);
EXPECT_EQ(OutLocs[1][0], RspDefInBlk0);
EXPECT_EQ(OutLocs[2][0], RspDefInBlk0);
EXPECT_EQ(OutLocs[3][0], RspDefInBlk0);
TransferFunc[0].clear();
// Def in one branch of the diamond means that we need a PHI in the ret block
TransferFunc[0].insert({RspLoc, RspDefInBlk0});
TransferFunc[1].insert({RspLoc, RspDefInBlk1});
initValueArray(InLocsPtr, 4, 2);
initValueArray(OutLocsPtr, 4, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
// This value map: like above, where RspDefInBlk0 is propagated through one
// branch of the diamond, but is def'ed in the live-outs of the other. The
// ret / merging block should have a PHI in its live-ins.
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspDefInBlk0);
EXPECT_EQ(InLocs[2][0], RspDefInBlk0);
EXPECT_EQ(InLocs[3][0], RspPHIInBlk3);
EXPECT_EQ(OutLocs[0][0], RspDefInBlk0);
EXPECT_EQ(OutLocs[1][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[2][0], RspDefInBlk0);
EXPECT_EQ(OutLocs[3][0], RspPHIInBlk3);
TransferFunc[0].clear();
TransferFunc[1].clear();
// If we have differeing defs in either side of the diamond, we should
// continue to produce a PHI,
TransferFunc[0].insert({RspLoc, RspDefInBlk0});
TransferFunc[1].insert({RspLoc, RspDefInBlk1});
TransferFunc[2].insert({RspLoc, RspDefInBlk2});
initValueArray(InLocsPtr, 4, 2);
initValueArray(OutLocsPtr, 4, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspDefInBlk0);
EXPECT_EQ(InLocs[2][0], RspDefInBlk0);
EXPECT_EQ(InLocs[3][0], RspPHIInBlk3);
EXPECT_EQ(OutLocs[0][0], RspDefInBlk0);
EXPECT_EQ(OutLocs[1][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[2][0], RspDefInBlk2);
EXPECT_EQ(OutLocs[3][0], RspPHIInBlk3);
TransferFunc[0].clear();
TransferFunc[1].clear();
TransferFunc[2].clear();
// If we have defs of the same value on either side of the branch, a PHI will
// initially be created, however value propagation should then eliminate it.
// Encode this by copying the live-in value to $rax, and copying it to $rsp
// from $rax in each branch of the diamond. We don't allow the definition of
// arbitary values in transfer functions.
TransferFunc[0].insert({RspLoc, RspDefInBlk0});
TransferFunc[0].insert({RaxLoc, LiveInRsp});
TransferFunc[1].insert({RspLoc, RaxLiveInBlk1});
TransferFunc[2].insert({RspLoc, RaxLiveInBlk2});
initValueArray(InLocsPtr, 4, 2);
initValueArray(OutLocsPtr, 4, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspDefInBlk0);
EXPECT_EQ(InLocs[2][0], RspDefInBlk0);
EXPECT_EQ(InLocs[3][0], LiveInRsp);
EXPECT_EQ(OutLocs[0][0], RspDefInBlk0);
EXPECT_EQ(OutLocs[1][0], LiveInRsp);
EXPECT_EQ(OutLocs[2][0], LiveInRsp);
EXPECT_EQ(OutLocs[3][0], LiveInRsp);
TransferFunc[0].clear();
TransferFunc[1].clear();
TransferFunc[2].clear();
}
TEST_F(InstrRefLDVTest, MLocDiamondSpills) {
// Test that defs in stack locations that require PHIs, cause PHIs to be
// installed in aliasing locations. i.e., if there's a PHI in the lower
// 8 bits of the stack, there should be PHIs for 16/32/64 bit locations
// on the stack too.
// Technically this isn't needed for accuracy: we should calculate PHIs
// independently for each location. However, because there's an optimisation
// that only places PHIs for the lower "interfering" parts of stack slots,
// test for this behaviour.
setupDiamondBlocks();
ASSERT_TRUE(MTracker->getNumLocs() == 1);
LocIdx RspLoc(0);
// Create a stack location and ensure it's tracked.
SpillLoc SL = {getRegByName("RSP"), StackOffset::getFixed(-8)};
SpillLocationNo SpillNo = MTracker->getOrTrackSpillLoc(SL);
ASSERT_EQ(MTracker->getNumLocs(), 10u); // Tracks all possible stack locs.
// Locations are: RSP, stack slots from 2^3 bits wide up to 2^9 for zmm regs,
// then slots for sub_8bit_hi and sub_16bit_hi ({8, 8} and {16, 16}).
// Pick out the locations on the stack that various x86 regs would be written
// to. HAX is the upper 16 bits of EAX.
unsigned ALID = MTracker->getLocID(SpillNo, {8, 0});
unsigned AHID = MTracker->getLocID(SpillNo, {8, 8});
unsigned AXID = MTracker->getLocID(SpillNo, {16, 0});
unsigned EAXID = MTracker->getLocID(SpillNo, {32, 0});
unsigned HAXID = MTracker->getLocID(SpillNo, {16, 16});
unsigned RAXID = MTracker->getLocID(SpillNo, {64, 0});
LocIdx ALStackLoc = MTracker->getSpillMLoc(ALID);
LocIdx AHStackLoc = MTracker->getSpillMLoc(AHID);
LocIdx AXStackLoc = MTracker->getSpillMLoc(AXID);
LocIdx EAXStackLoc = MTracker->getSpillMLoc(EAXID);
LocIdx HAXStackLoc = MTracker->getSpillMLoc(HAXID);
LocIdx RAXStackLoc = MTracker->getSpillMLoc(RAXID);
// There are other locations, for things like xmm0, which we're going to
// ignore here.
ValueIDNum InLocs[4][10];
ValueIDNum *InLocsPtr[4] = {InLocs[0], InLocs[1], InLocs[2], InLocs[3]};
// Transfer function: start with nothing.
SmallVector<MLocTransferMap, 1> TransferFunc;
TransferFunc.resize(4);
// Name some values.
unsigned EntryBlk = 0, Blk1 = 1, RetBlk = 3;
ValueIDNum LiveInRsp(EntryBlk, 0, RspLoc);
ValueIDNum ALLiveIn(EntryBlk, 0, ALStackLoc);
ValueIDNum AHLiveIn(EntryBlk, 0, AHStackLoc);
ValueIDNum HAXLiveIn(EntryBlk, 0, HAXStackLoc);
ValueIDNum ALPHI(RetBlk, 0, ALStackLoc);
ValueIDNum AXPHI(RetBlk, 0, AXStackLoc);
ValueIDNum EAXPHI(RetBlk, 0, EAXStackLoc);
ValueIDNum HAXPHI(RetBlk, 0, HAXStackLoc);
ValueIDNum RAXPHI(RetBlk, 0, RAXStackLoc);
ValueIDNum ALDefInBlk1(Blk1, 1, ALStackLoc);
ValueIDNum HAXDefInBlk1(Blk1, 1, HAXStackLoc);
SmallPtrSet<MachineBasicBlock *, 4> AllBlocks{MBB0, MBB1, MBB2, MBB3};
// If we put defs into one side of the diamond, for AL and HAX, then we should
// find all aliasing positions have PHIs placed. This isn't technically what
// the transfer function says to do: but we're testing that the optimisation
// to reduce IDF calculation does the right thing.
// AH should not be def'd: it don't alias AL or HAX.
//
// NB: we don't call buildMLocValueMap, because it will try to eliminate the
// upper-slot PHIs, and succeed because of our slightly cooked transfer
// function.
TransferFunc[1].insert({ALStackLoc, ALDefInBlk1});
TransferFunc[1].insert({HAXStackLoc, HAXDefInBlk1});
initValueArray(InLocsPtr, 4, 10);
placeMLocPHIs(*MF, AllBlocks, InLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[3][ALStackLoc.asU64()], ALPHI);
EXPECT_EQ(InLocs[3][AXStackLoc.asU64()], AXPHI);
EXPECT_EQ(InLocs[3][EAXStackLoc.asU64()], EAXPHI);
EXPECT_EQ(InLocs[3][HAXStackLoc.asU64()], HAXPHI);
EXPECT_EQ(InLocs[3][RAXStackLoc.asU64()], RAXPHI);
// AH should be left untouched,
EXPECT_EQ(InLocs[3][AHStackLoc.asU64()], ValueIDNum::EmptyValue);
}
TEST_F(InstrRefLDVTest, MLocSimpleLoop) {
// entry
// |
// |/-----\
// loopblk |
// |\-----/
// |
// ret
setupSimpleLoop();
ASSERT_TRUE(MTracker->getNumLocs() == 1);
LocIdx RspLoc(0);
Register RAX = getRegByName("RAX");
LocIdx RaxLoc = MTracker->lookupOrTrackRegister(RAX);
ValueIDNum InLocs[3][2], OutLocs[3][2];
ValueIDNum *InLocsPtr[3] = {InLocs[0], InLocs[1], InLocs[2]};
ValueIDNum *OutLocsPtr[3] = {OutLocs[0], OutLocs[1], OutLocs[2]};
SmallVector<MLocTransferMap, 1> TransferFunc;
TransferFunc.resize(3);
// Name some values.
unsigned EntryBlk = 0, LoopBlk = 1, RetBlk = 2;
ValueIDNum LiveInRsp(EntryBlk, 0, RspLoc);
ValueIDNum RspPHIInBlk1(LoopBlk, 0, RspLoc);
ValueIDNum RspDefInBlk1(LoopBlk, 1, RspLoc);
ValueIDNum LiveInRax(EntryBlk, 0, RaxLoc);
ValueIDNum RaxPHIInBlk1(LoopBlk, 0, RaxLoc);
ValueIDNum RaxPHIInBlk2(RetBlk, 0, RaxLoc);
// Begin test with all locations being live-through.
initValueArray(InLocsPtr, 3, 2);
initValueArray(OutLocsPtr, 3, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], LiveInRsp);
EXPECT_EQ(InLocs[2][0], LiveInRsp);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], LiveInRsp);
EXPECT_EQ(OutLocs[2][0], LiveInRsp);
// Add a def of $rsp to the loop block: it should be in the live-outs, but
// should cause a PHI to be placed in the live-ins. Test the transfer function
// by copying that PHI into $rax in the loop, then back to $rsp in the ret
// block.
TransferFunc[1].insert({RspLoc, RspDefInBlk1});
TransferFunc[1].insert({RaxLoc, RspPHIInBlk1});
TransferFunc[2].insert({RspLoc, RaxPHIInBlk2});
initValueArray(InLocsPtr, 3, 2);
initValueArray(OutLocsPtr, 3, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[2][0], RspPHIInBlk1);
// Check rax as well,
EXPECT_EQ(InLocs[0][1], LiveInRax);
EXPECT_EQ(InLocs[1][1], RaxPHIInBlk1);
EXPECT_EQ(InLocs[2][1], RspPHIInBlk1);
EXPECT_EQ(OutLocs[0][1], LiveInRax);
EXPECT_EQ(OutLocs[1][1], RspPHIInBlk1);
EXPECT_EQ(OutLocs[2][1], RspPHIInBlk1);
TransferFunc[1].clear();
TransferFunc[2].clear();
// As with the diamond case, a PHI will be created if there's a (implicit)
// def in the entry block and loop block; but should be value propagated away
// if it copies in the same value. Copy live-in $rsp to $rax, then copy it
// into $rsp in the loop. Encoded as copying the live-in $rax value in block 1
// to $rsp.
TransferFunc[0].insert({RaxLoc, LiveInRsp});
TransferFunc[1].insert({RspLoc, RaxPHIInBlk1});
initValueArray(InLocsPtr, 3, 2);
initValueArray(OutLocsPtr, 3, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], LiveInRsp);
EXPECT_EQ(InLocs[2][0], LiveInRsp);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], LiveInRsp);
EXPECT_EQ(OutLocs[2][0], LiveInRsp);
// Check $rax's values.
EXPECT_EQ(InLocs[0][1], LiveInRax);
EXPECT_EQ(InLocs[1][1], LiveInRsp);
EXPECT_EQ(InLocs[2][1], LiveInRsp);
EXPECT_EQ(OutLocs[0][1], LiveInRsp);
EXPECT_EQ(OutLocs[1][1], LiveInRsp);
EXPECT_EQ(OutLocs[2][1], LiveInRsp);
TransferFunc[0].clear();
TransferFunc[1].clear();
}
TEST_F(InstrRefLDVTest, MLocNestedLoop) {
// entry
// |
// loop1
// ^\
// | \ /-\
// | loop2 |
// | / \-/
// ^ /
// join
// |
// ret
setupNestedLoops();
ASSERT_TRUE(MTracker->getNumLocs() == 1);
LocIdx RspLoc(0);
Register RAX = getRegByName("RAX");
LocIdx RaxLoc = MTracker->lookupOrTrackRegister(RAX);
ValueIDNum InLocs[5][2], OutLocs[5][2];
ValueIDNum *InLocsPtr[5] = {InLocs[0], InLocs[1], InLocs[2], InLocs[3],
InLocs[4]};
ValueIDNum *OutLocsPtr[5] = {OutLocs[0], OutLocs[1], OutLocs[2], OutLocs[3],
OutLocs[4]};
SmallVector<MLocTransferMap, 1> TransferFunc;
TransferFunc.resize(5);
unsigned EntryBlk = 0, Loop1Blk = 1, Loop2Blk = 2, JoinBlk = 3;
ValueIDNum LiveInRsp(EntryBlk, 0, RspLoc);
ValueIDNum RspPHIInBlk1(Loop1Blk, 0, RspLoc);
ValueIDNum RspDefInBlk1(Loop1Blk, 1, RspLoc);
ValueIDNum RspPHIInBlk2(Loop2Blk, 0, RspLoc);
ValueIDNum RspDefInBlk2(Loop2Blk, 1, RspLoc);
ValueIDNum RspDefInBlk3(JoinBlk, 1, RspLoc);
ValueIDNum LiveInRax(EntryBlk, 0, RaxLoc);
ValueIDNum RaxPHIInBlk1(Loop1Blk, 0, RaxLoc);
ValueIDNum RaxPHIInBlk2(Loop2Blk, 0, RaxLoc);
// Like the other tests: first ensure that if there's nothing in the transfer
// function, then everything is live-through (check $rsp).
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], LiveInRsp);
EXPECT_EQ(InLocs[2][0], LiveInRsp);
EXPECT_EQ(InLocs[3][0], LiveInRsp);
EXPECT_EQ(InLocs[4][0], LiveInRsp);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], LiveInRsp);
EXPECT_EQ(OutLocs[2][0], LiveInRsp);
EXPECT_EQ(OutLocs[3][0], LiveInRsp);
EXPECT_EQ(OutLocs[4][0], LiveInRsp);
// A def in the inner loop means we should get PHIs at the heads of both
// loops. Live-outs of the last three blocks will be the def, as it dominates
// those.
TransferFunc[2].insert({RspLoc, RspDefInBlk2});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(InLocs[3][0], RspDefInBlk2);
EXPECT_EQ(InLocs[4][0], RspDefInBlk2);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(OutLocs[2][0], RspDefInBlk2);
EXPECT_EQ(OutLocs[3][0], RspDefInBlk2);
EXPECT_EQ(OutLocs[4][0], RspDefInBlk2);
TransferFunc[2].clear();
// Adding a def to the outer loop header shouldn't affect this much -- the
// live-out of block 1 changes.
TransferFunc[1].insert({RspLoc, RspDefInBlk1});
TransferFunc[2].insert({RspLoc, RspDefInBlk2});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(InLocs[3][0], RspDefInBlk2);
EXPECT_EQ(InLocs[4][0], RspDefInBlk2);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[2][0], RspDefInBlk2);
EXPECT_EQ(OutLocs[3][0], RspDefInBlk2);
EXPECT_EQ(OutLocs[4][0], RspDefInBlk2);
TransferFunc[1].clear();
TransferFunc[2].clear();
// Likewise, putting a def in the outer loop tail shouldn't affect where
// the PHIs go, and should propagate into the ret block.
TransferFunc[1].insert({RspLoc, RspDefInBlk1});
TransferFunc[2].insert({RspLoc, RspDefInBlk2});
TransferFunc[3].insert({RspLoc, RspDefInBlk3});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(InLocs[3][0], RspDefInBlk2);
EXPECT_EQ(InLocs[4][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[2][0], RspDefInBlk2);
EXPECT_EQ(OutLocs[3][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[4][0], RspDefInBlk3);
TransferFunc[1].clear();
TransferFunc[2].clear();
TransferFunc[3].clear();
// However: if we don't def in the inner-loop, then we just have defs in the
// head and tail of the outer loop. The inner loop should be live-through.
TransferFunc[1].insert({RspLoc, RspDefInBlk1});
TransferFunc[3].insert({RspLoc, RspDefInBlk3});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspDefInBlk1);
EXPECT_EQ(InLocs[3][0], RspDefInBlk1);
EXPECT_EQ(InLocs[4][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[2][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[3][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[4][0], RspDefInBlk3);
TransferFunc[1].clear();
TransferFunc[3].clear();
// Check that this still works if we copy RspDefInBlk1 to $rax and then
// copy it back into $rsp in the inner loop.
TransferFunc[1].insert({RspLoc, RspDefInBlk1});
TransferFunc[1].insert({RaxLoc, RspDefInBlk1});
TransferFunc[2].insert({RspLoc, RaxPHIInBlk2});
TransferFunc[3].insert({RspLoc, RspDefInBlk3});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspDefInBlk1);
EXPECT_EQ(InLocs[3][0], RspDefInBlk1);
EXPECT_EQ(InLocs[4][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[2][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[3][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[4][0], RspDefInBlk3);
// Look at raxes value in the relevant blocks,
EXPECT_EQ(InLocs[2][1], RspDefInBlk1);
EXPECT_EQ(OutLocs[1][1], RspDefInBlk1);
TransferFunc[1].clear();
TransferFunc[2].clear();
TransferFunc[3].clear();
// If we have a single def in the tail of the outer loop, that should produce
// a PHI at the loop head, and be live-through the inner loop.
TransferFunc[3].insert({RspLoc, RspDefInBlk3});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[3][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[4][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(OutLocs[2][0], RspPHIInBlk1);
EXPECT_EQ(OutLocs[3][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[4][0], RspDefInBlk3);
TransferFunc[3].clear();
// And if we copy from $rsp to $rax in block 2, it should resolve to the PHI
// in block 1, and we should keep that value in rax until the ret block.
// There'll be a PHI in block 1 and 2, because we're putting a def in the
// inner loop.
TransferFunc[2].insert({RaxLoc, RspPHIInBlk2});
TransferFunc[3].insert({RspLoc, RspDefInBlk3});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
// Examining the values of rax,
EXPECT_EQ(InLocs[0][1], LiveInRax);
EXPECT_EQ(InLocs[1][1], RaxPHIInBlk1);
EXPECT_EQ(InLocs[2][1], RaxPHIInBlk2);
EXPECT_EQ(InLocs[3][1], RspPHIInBlk1);
EXPECT_EQ(InLocs[4][1], RspPHIInBlk1);
EXPECT_EQ(OutLocs[0][1], LiveInRax);
EXPECT_EQ(OutLocs[1][1], RaxPHIInBlk1);
EXPECT_EQ(OutLocs[2][1], RspPHIInBlk1);
EXPECT_EQ(OutLocs[3][1], RspPHIInBlk1);
EXPECT_EQ(OutLocs[4][1], RspPHIInBlk1);
TransferFunc[2].clear();
TransferFunc[3].clear();
}
TEST_F(InstrRefLDVTest, MLocNoDominatingLoop) {
// entry
// / \
// / \
// / \
// head1 head2
// ^ \ / ^
// ^ \ / ^
// \-joinblk -/
// |
// ret
setupNoDominatingLoop();
ASSERT_TRUE(MTracker->getNumLocs() == 1);
LocIdx RspLoc(0);
Register RAX = getRegByName("RAX");
LocIdx RaxLoc = MTracker->lookupOrTrackRegister(RAX);
ValueIDNum InLocs[5][2], OutLocs[5][2];
ValueIDNum *InLocsPtr[5] = {InLocs[0], InLocs[1], InLocs[2], InLocs[3],
InLocs[4]};
ValueIDNum *OutLocsPtr[5] = {OutLocs[0], OutLocs[1], OutLocs[2], OutLocs[3],
OutLocs[4]};
SmallVector<MLocTransferMap, 1> TransferFunc;
TransferFunc.resize(5);
unsigned EntryBlk = 0, Head1Blk = 1, Head2Blk = 2, JoinBlk = 3;
ValueIDNum LiveInRsp(EntryBlk, 0, RspLoc);
ValueIDNum RspPHIInBlk1(Head1Blk, 0, RspLoc);
ValueIDNum RspDefInBlk1(Head1Blk, 1, RspLoc);
ValueIDNum RspPHIInBlk2(Head2Blk, 0, RspLoc);
ValueIDNum RspDefInBlk2(Head2Blk, 1, RspLoc);
ValueIDNum RspPHIInBlk3(JoinBlk, 0, RspLoc);
ValueIDNum RspDefInBlk3(JoinBlk, 1, RspLoc);
ValueIDNum RaxPHIInBlk1(Head1Blk, 0, RaxLoc);
ValueIDNum RaxPHIInBlk2(Head2Blk, 0, RaxLoc);
// As ever, test that everything is live-through if there are no defs.
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], LiveInRsp);
EXPECT_EQ(InLocs[2][0], LiveInRsp);
EXPECT_EQ(InLocs[3][0], LiveInRsp);
EXPECT_EQ(InLocs[4][0], LiveInRsp);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], LiveInRsp);
EXPECT_EQ(OutLocs[2][0], LiveInRsp);
EXPECT_EQ(OutLocs[3][0], LiveInRsp);
EXPECT_EQ(OutLocs[4][0], LiveInRsp);
// Putting a def in the 'join' block will cause us to have two distinct
// PHIs in each loop head, then on entry to the join block.
TransferFunc[3].insert({RspLoc, RspDefInBlk3});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(InLocs[3][0], RspPHIInBlk3);
EXPECT_EQ(InLocs[4][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(OutLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(OutLocs[3][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[4][0], RspDefInBlk3);
TransferFunc[3].clear();
// We should get the same behaviour if we put the def in either of the
// loop heads -- it should force the other head to be a PHI.
TransferFunc[1].insert({RspLoc, RspDefInBlk1});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(InLocs[3][0], RspPHIInBlk3);
EXPECT_EQ(InLocs[4][0], RspPHIInBlk3);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(OutLocs[3][0], RspPHIInBlk3);
EXPECT_EQ(OutLocs[4][0], RspPHIInBlk3);
TransferFunc[1].clear();
// Check symmetry,
TransferFunc[2].insert({RspLoc, RspDefInBlk2});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(InLocs[3][0], RspPHIInBlk3);
EXPECT_EQ(InLocs[4][0], RspPHIInBlk3);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(OutLocs[2][0], RspDefInBlk2);
EXPECT_EQ(OutLocs[3][0], RspPHIInBlk3);
EXPECT_EQ(OutLocs[4][0], RspPHIInBlk3);
TransferFunc[2].clear();
// Test some scenarios where there _shouldn't_ be any PHIs created at heads.
// These are those PHIs are created, but value propagation eliminates them.
// For example, lets copy rsp-livein to $rsp inside each loop head, so that
// there's no need for a PHI in the join block. Put a def of $rsp in block 3
// to force PHIs elsewhere.
TransferFunc[0].insert({RaxLoc, LiveInRsp});
TransferFunc[1].insert({RspLoc, RaxPHIInBlk1});
TransferFunc[2].insert({RspLoc, RaxPHIInBlk2});
TransferFunc[3].insert({RspLoc, RspDefInBlk3});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(InLocs[3][0], LiveInRsp);
EXPECT_EQ(InLocs[4][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], LiveInRsp);
EXPECT_EQ(OutLocs[2][0], LiveInRsp);
EXPECT_EQ(OutLocs[3][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[4][0], RspDefInBlk3);
TransferFunc[0].clear();
TransferFunc[1].clear();
TransferFunc[2].clear();
TransferFunc[3].clear();
// In fact, if we eliminate the def in block 3, none of those PHIs are
// necessary, as we're just repeatedly copying LiveInRsp into $rsp. They
// should all be value propagated out.
TransferFunc[0].insert({RaxLoc, LiveInRsp});
TransferFunc[1].insert({RspLoc, RaxPHIInBlk1});
TransferFunc[2].insert({RspLoc, RaxPHIInBlk2});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], LiveInRsp);
EXPECT_EQ(InLocs[2][0], LiveInRsp);
EXPECT_EQ(InLocs[3][0], LiveInRsp);
EXPECT_EQ(InLocs[4][0], LiveInRsp);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], LiveInRsp);
EXPECT_EQ(OutLocs[2][0], LiveInRsp);
EXPECT_EQ(OutLocs[3][0], LiveInRsp);
EXPECT_EQ(OutLocs[4][0], LiveInRsp);
TransferFunc[0].clear();
TransferFunc[1].clear();
TransferFunc[2].clear();
}
TEST_F(InstrRefLDVTest, MLocBadlyNestedLoops) {
// entry
// |
// loop1 -o
// | ^
// | ^
// loop2 -o
// | ^
// | ^
// loop3 -o
// |
// ret
setupBadlyNestedLoops();
ASSERT_TRUE(MTracker->getNumLocs() == 1);
LocIdx RspLoc(0);
Register RAX = getRegByName("RAX");
LocIdx RaxLoc = MTracker->lookupOrTrackRegister(RAX);
ValueIDNum InLocs[5][2], OutLocs[5][2];
ValueIDNum *InLocsPtr[5] = {InLocs[0], InLocs[1], InLocs[2], InLocs[3],
InLocs[4]};
ValueIDNum *OutLocsPtr[5] = {OutLocs[0], OutLocs[1], OutLocs[2], OutLocs[3],
OutLocs[4]};
SmallVector<MLocTransferMap, 1> TransferFunc;
TransferFunc.resize(5);
unsigned EntryBlk = 0, Loop1Blk = 1, Loop2Blk = 2, Loop3Blk = 3;
ValueIDNum LiveInRsp(EntryBlk, 0, RspLoc);
ValueIDNum RspPHIInBlk1(Loop1Blk, 0, RspLoc);
ValueIDNum RspDefInBlk1(Loop1Blk, 1, RspLoc);
ValueIDNum RspPHIInBlk2(Loop2Blk, 0, RspLoc);
ValueIDNum RspPHIInBlk3(Loop3Blk, 0, RspLoc);
ValueIDNum RspDefInBlk3(Loop3Blk, 1, RspLoc);
ValueIDNum LiveInRax(EntryBlk, 0, RaxLoc);
ValueIDNum RaxPHIInBlk3(Loop3Blk, 0, RaxLoc);
// As ever, test that everything is live-through if there are no defs.
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], LiveInRsp);
EXPECT_EQ(InLocs[2][0], LiveInRsp);
EXPECT_EQ(InLocs[3][0], LiveInRsp);
EXPECT_EQ(InLocs[4][0], LiveInRsp);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], LiveInRsp);
EXPECT_EQ(OutLocs[2][0], LiveInRsp);
EXPECT_EQ(OutLocs[3][0], LiveInRsp);
EXPECT_EQ(OutLocs[4][0], LiveInRsp);
// A def in loop3 should cause PHIs in every loop block: they're all
// reachable from each other.
TransferFunc[3].insert({RspLoc, RspDefInBlk3});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(InLocs[3][0], RspPHIInBlk3);
EXPECT_EQ(InLocs[4][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(OutLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(OutLocs[3][0], RspDefInBlk3);
EXPECT_EQ(OutLocs[4][0], RspDefInBlk3);
TransferFunc[3].clear();
// A def in loop1 should cause a PHI in loop1, but not the other blocks.
// loop2 and loop3 are dominated by the def in loop1, so they should have
// that value live-through.
TransferFunc[1].insert({RspLoc, RspDefInBlk1});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspDefInBlk1);
EXPECT_EQ(InLocs[3][0], RspDefInBlk1);
EXPECT_EQ(InLocs[4][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[2][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[3][0], RspDefInBlk1);
EXPECT_EQ(OutLocs[4][0], RspDefInBlk1);
TransferFunc[1].clear();
// As with earlier tricks: copy $rsp to $rax in the entry block, then $rax
// to $rsp in block 3. The only def of $rsp is simply copying the same value
// back into itself, and the value of $rsp is LiveInRsp all the way through.
// PHIs should be created, then value-propagated away... however this
// doesn't work in practice.
// Consider the entry to loop3: we can determine that there's an incoming
// PHI value from loop2, and LiveInRsp from the self-loop. This would still
// justify having a PHI on entry to loop3. The only way to completely
// value-propagate these PHIs away would be to speculatively explore what
// PHIs could be eliminated and what that would lead to; which is
// combinatorially complex.
// Happily:
// a) In this scenario, we always have a tracked location for LiveInRsp
// anyway, so there's no loss in availability,
// b) Only DBG_PHIs of a register would be vunlerable to this scenario, and
// even then only if a true PHI became a DBG_PHI and was then optimised
// through branch folding to no longer be at a CFG join,
// c) The register allocator can spot this kind of redundant COPY easily,
// and eliminate it.
//
// This unit test left in as a reference for the limitations of this
// approach. PHIs will be left in $rsp on entry to each block.
TransferFunc[0].insert({RaxLoc, LiveInRsp});
TransferFunc[3].insert({RspLoc, RaxPHIInBlk3});
initValueArray(InLocsPtr, 5, 2);
initValueArray(OutLocsPtr, 5, 2);
buildMLocValueMap(InLocsPtr, OutLocsPtr, TransferFunc);
EXPECT_EQ(InLocs[0][0], LiveInRsp);
EXPECT_EQ(InLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(InLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(InLocs[3][0], RspPHIInBlk3);
EXPECT_EQ(InLocs[4][0], LiveInRsp);
EXPECT_EQ(OutLocs[0][0], LiveInRsp);
EXPECT_EQ(OutLocs[1][0], RspPHIInBlk1);
EXPECT_EQ(OutLocs[2][0], RspPHIInBlk2);
EXPECT_EQ(OutLocs[3][0], LiveInRsp);
EXPECT_EQ(OutLocs[4][0], LiveInRsp);
// Check $rax's value. It should have $rsps value from the entry block
// onwards.
EXPECT_EQ(InLocs[0][1], LiveInRax);
EXPECT_EQ(InLocs[1][1], LiveInRsp);
EXPECT_EQ(InLocs[2][1], LiveInRsp);
EXPECT_EQ(InLocs[3][1], LiveInRsp);
EXPECT_EQ(InLocs[4][1], LiveInRsp);
EXPECT_EQ(OutLocs[0][1], LiveInRsp);
EXPECT_EQ(OutLocs[1][1], LiveInRsp);
EXPECT_EQ(OutLocs[2][1], LiveInRsp);
EXPECT_EQ(OutLocs[3][1], LiveInRsp);
EXPECT_EQ(OutLocs[4][1], LiveInRsp);
}
TEST_F(InstrRefLDVTest, pickVPHILocDiamond) {
// entry
// / \
// br1 br2
// \ /
// ret
setupDiamondBlocks();
ASSERT_TRUE(MTracker->getNumLocs() == 1);
LocIdx RspLoc(0);
Register RAX = getRegByName("RAX");
LocIdx RaxLoc = MTracker->lookupOrTrackRegister(RAX);
ValueIDNum OutLocs[4][2];
ValueIDNum *OutLocsPtr[4] = {OutLocs[0], OutLocs[1], OutLocs[2], OutLocs[3]};
initValueArray(OutLocsPtr, 4, 2);
unsigned EntryBlk = 0, Br2Blk = 2, RetBlk = 3;
ValueIDNum LiveInRsp(EntryBlk, 0, RspLoc);
ValueIDNum LiveInRax(EntryBlk, 0, RaxLoc);
ValueIDNum RspPHIInBlk2(Br2Blk, 0, RspLoc);
ValueIDNum RspPHIInBlk3(RetBlk, 0, RspLoc);
DebugVariable Var(FuncVariable, None, nullptr);
DbgValueProperties EmptyProps(EmptyExpr, false);
SmallVector<DbgValue, 32> VLiveOuts;
VLiveOuts.resize(4, DbgValue(EmptyProps, DbgValue::Undef));
InstrRefBasedLDV::LiveIdxT VLiveOutIdx;
VLiveOutIdx[MBB0] = &VLiveOuts[0];
VLiveOutIdx[MBB1] = &VLiveOuts[1];
VLiveOutIdx[MBB2] = &VLiveOuts[2];
VLiveOutIdx[MBB3] = &VLiveOuts[3];
SmallVector<const MachineBasicBlock *, 2> Preds;
for (const auto *Pred : MBB3->predecessors())
Preds.push_back(Pred);
// Specify the live-outs around the joining block.
OutLocs[1][0] = LiveInRsp;
OutLocs[2][0] = LiveInRax;
Optional<ValueIDNum> Result;
// Simple case: join two distinct values on entry to the block.
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(LiveInRax, EmptyProps, DbgValue::Def);
Result = pickVPHILoc(*MBB3, Var, VLiveOutIdx, OutLocsPtr, Preds);
// Should have picked a PHI in $rsp in block 3.
EXPECT_TRUE(Result);
if (Result) {
EXPECT_EQ(*Result, RspPHIInBlk3);
}
// If the incoming values are swapped between blocks, we should not
// successfully join. The CFG merge would select the right values, but in
// the wrong conditions.
std::swap(VLiveOuts[1], VLiveOuts[2]);
Result = pickVPHILoc(*MBB3, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
// Swap back,
std::swap(VLiveOuts[1], VLiveOuts[2]);
// Setting one of these to being a constant should prohibit merging.
VLiveOuts[1].Kind = DbgValue::Const;
VLiveOuts[1].MO = MachineOperand::CreateImm(0);
Result = pickVPHILoc(*MBB3, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
// Seeing both to being a constant -> still prohibit, it shouldn't become
// a value in the register file anywhere.
VLiveOuts[2] = VLiveOuts[1];
Result = pickVPHILoc(*MBB3, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
// NoVals shouldn't join with anything else.
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(2, EmptyProps, DbgValue::NoVal);
Result = pickVPHILoc(*MBB3, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
// We might merge in another VPHI in such a join. Present pickVPHILoc with
// such a scenario: first, where one incoming edge has a VPHI with no known
// value. This represents an edge where there was a PHI value that can't be
// found in the register file -- we can't subsequently find a PHI here.
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(2, EmptyProps, DbgValue::VPHI);
EXPECT_EQ(VLiveOuts[2].ID, ValueIDNum::EmptyValue);
Result = pickVPHILoc(*MBB3, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
// However, if we know the value of the incoming VPHI, we can search for its
// location. Use a PHI machine-value for doing this, as VPHIs should always
// have PHI values, or they should have been eliminated.
OutLocs[2][0] = RspPHIInBlk2;
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(2, EmptyProps, DbgValue::VPHI);
VLiveOuts[2].ID = RspPHIInBlk2; // Set location where PHI happens.
Result = pickVPHILoc(*MBB3, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_TRUE(Result);
if (Result) {
EXPECT_EQ(*Result, RspPHIInBlk3);
}
// If that value isn't available from that block, don't join.
OutLocs[2][0] = LiveInRsp;
Result = pickVPHILoc(*MBB3, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
// Check that we don't pick values when the properties disagree, for example
// different indirectness or DIExpression.
DIExpression *NewExpr =
DIExpression::prepend(EmptyExpr, DIExpression::ApplyOffset, 4);
DbgValueProperties PropsWithExpr(NewExpr, false);
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(LiveInRsp, PropsWithExpr, DbgValue::Def);
Result = pickVPHILoc(*MBB3, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
DbgValueProperties PropsWithIndirect(EmptyExpr, true);
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(LiveInRsp, PropsWithIndirect, DbgValue::Def);
Result = pickVPHILoc(*MBB3, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
}
TEST_F(InstrRefLDVTest, pickVPHILocLoops) {
setupSimpleLoop();
// entry
// |
// |/-----\
// loopblk |
// |\-----/
// |
// ret
ASSERT_TRUE(MTracker->getNumLocs() == 1);
LocIdx RspLoc(0);
Register RAX = getRegByName("RAX");
LocIdx RaxLoc = MTracker->lookupOrTrackRegister(RAX);
ValueIDNum OutLocs[3][2];
ValueIDNum *OutLocsPtr[4] = {OutLocs[0], OutLocs[1], OutLocs[2]};
initValueArray(OutLocsPtr, 3, 2);
unsigned EntryBlk = 0, LoopBlk = 1;
ValueIDNum LiveInRsp(EntryBlk, 0, RspLoc);
ValueIDNum LiveInRax(EntryBlk, 0, RaxLoc);
ValueIDNum RspPHIInBlk1(LoopBlk, 0, RspLoc);
ValueIDNum RaxPHIInBlk1(LoopBlk, 0, RaxLoc);
DebugVariable Var(FuncVariable, None, nullptr);
DbgValueProperties EmptyProps(EmptyExpr, false);
SmallVector<DbgValue, 32> VLiveOuts;
VLiveOuts.resize(3, DbgValue(EmptyProps, DbgValue::Undef));
InstrRefBasedLDV::LiveIdxT VLiveOutIdx;
VLiveOutIdx[MBB0] = &VLiveOuts[0];
VLiveOutIdx[MBB1] = &VLiveOuts[1];
VLiveOutIdx[MBB2] = &VLiveOuts[2];
SmallVector<const MachineBasicBlock *, 2> Preds;
for (const auto *Pred : MBB1->predecessors())
Preds.push_back(Pred);
// Specify the live-outs around the joining block.
OutLocs[0][0] = LiveInRsp;
OutLocs[1][0] = LiveInRax;
Optional<ValueIDNum> Result;
// See that we can merge as normal on a backedge.
VLiveOuts[0] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[1] = DbgValue(LiveInRax, EmptyProps, DbgValue::Def);
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
// Should have picked a PHI in $rsp in block 1.
EXPECT_TRUE(Result);
if (Result) {
EXPECT_EQ(*Result, RspPHIInBlk1);
}
// And that, if the desired values aren't available, we don't merge.
OutLocs[1][0] = LiveInRsp;
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
// Test the backedge behaviour: PHIs that feed back into themselves can
// carry this variables value. Feed in LiveInRsp in both $rsp and $rax
// from the entry block, but only put an appropriate backedge PHI in $rax.
// Only the $rax location can form the correct PHI.
OutLocs[0][0] = LiveInRsp;
OutLocs[0][1] = LiveInRsp;
OutLocs[1][0] = RaxPHIInBlk1;
OutLocs[1][1] = RaxPHIInBlk1;
VLiveOuts[0] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
// Crucially, a VPHI originating in this block:
VLiveOuts[1] = DbgValue(1, EmptyProps, DbgValue::VPHI);
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_TRUE(Result);
if (Result) {
EXPECT_EQ(*Result, RaxPHIInBlk1);
}
// Merging should not be permitted if there's a usable PHI on the backedge,
// but it's in the wrong place. (Overwrite $rax).
OutLocs[1][1] = LiveInRax;
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
// Additionally, if the VPHI coming back on the loop backedge isn't from
// this block (block 1), we can't merge it.
OutLocs[1][1] = RaxPHIInBlk1;
VLiveOuts[0] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[1] = DbgValue(0, EmptyProps, DbgValue::VPHI);
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
}
TEST_F(InstrRefLDVTest, pickVPHILocBadlyNestedLoops) {
// Run some tests similar to pickVPHILocLoops, with more than one backedge,
// and check that we merge correctly over many candidate locations.
setupBadlyNestedLoops();
// entry
// |
// loop1 -o
// | ^
// | ^
// loop2 -o
// | ^
// | ^
// loop3 -o
// |
// ret
ASSERT_TRUE(MTracker->getNumLocs() == 1);
LocIdx RspLoc(0);
Register RAX = getRegByName("RAX");
LocIdx RaxLoc = MTracker->lookupOrTrackRegister(RAX);
Register RBX = getRegByName("RBX");
LocIdx RbxLoc = MTracker->lookupOrTrackRegister(RBX);
ValueIDNum OutLocs[5][3];
ValueIDNum *OutLocsPtr[5] = {OutLocs[0], OutLocs[1], OutLocs[2], OutLocs[3], OutLocs[4]};
initValueArray(OutLocsPtr, 5, 3);
unsigned EntryBlk = 0, Loop1Blk = 1;
ValueIDNum LiveInRsp(EntryBlk, 0, RspLoc);
ValueIDNum LiveInRax(EntryBlk, 0, RaxLoc);
ValueIDNum LiveInRbx(EntryBlk, 0, RbxLoc);
ValueIDNum RspPHIInBlk1(Loop1Blk, 0, RspLoc);
ValueIDNum RaxPHIInBlk1(Loop1Blk, 0, RaxLoc);
ValueIDNum RbxPHIInBlk1(Loop1Blk, 0, RbxLoc);
DebugVariable Var(FuncVariable, None, nullptr);
DbgValueProperties EmptyProps(EmptyExpr, false);
SmallVector<DbgValue, 32> VLiveOuts;
VLiveOuts.resize(5, DbgValue(EmptyProps, DbgValue::Undef));
InstrRefBasedLDV::LiveIdxT VLiveOutIdx;
VLiveOutIdx[MBB0] = &VLiveOuts[0];
VLiveOutIdx[MBB1] = &VLiveOuts[1];
VLiveOutIdx[MBB2] = &VLiveOuts[2];
VLiveOutIdx[MBB3] = &VLiveOuts[3];
VLiveOutIdx[MBB4] = &VLiveOuts[4];
// We're going to focus on block 1.
SmallVector<const MachineBasicBlock *, 2> Preds;
for (const auto *Pred : MBB1->predecessors())
Preds.push_back(Pred);
// Specify the live-outs around the joining block. Incoming edges from the
// entry block, self, and loop2.
OutLocs[0][0] = LiveInRsp;
OutLocs[1][0] = LiveInRax;
OutLocs[2][0] = LiveInRbx;
Optional<ValueIDNum> Result;
// See that we can merge as normal on a backedge.
VLiveOuts[0] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[1] = DbgValue(LiveInRax, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(LiveInRbx, EmptyProps, DbgValue::Def);
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
// Should have picked a PHI in $rsp in block 1.
EXPECT_TRUE(Result);
if (Result) {
EXPECT_EQ(*Result, RspPHIInBlk1);
}
// Check too that permuting the live-out locations prevents merging
OutLocs[0][0] = LiveInRax;
OutLocs[1][0] = LiveInRbx;
OutLocs[2][0] = LiveInRsp;
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
OutLocs[0][0] = LiveInRsp;
OutLocs[1][0] = LiveInRax;
OutLocs[2][0] = LiveInRbx;
// Feeding a PHI back on one backedge shouldn't merge (block 1 self backedge
// wants LiveInRax).
OutLocs[1][0] = RspPHIInBlk1;
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
// If the variables value on that edge is a VPHI feeding into itself, that's
// fine.
VLiveOuts[0] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[1] = DbgValue(1, EmptyProps, DbgValue::VPHI);
VLiveOuts[2] = DbgValue(LiveInRbx, EmptyProps, DbgValue::Def);
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_TRUE(Result);
if (Result) {
EXPECT_EQ(*Result, RspPHIInBlk1);
}
// Likewise: the other backedge being a VPHI from block 1 should be accepted.
OutLocs[2][0] = RspPHIInBlk1;
VLiveOuts[0] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[1] = DbgValue(1, EmptyProps, DbgValue::VPHI);
VLiveOuts[2] = DbgValue(1, EmptyProps, DbgValue::VPHI);
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_TRUE(Result);
if (Result) {
EXPECT_EQ(*Result, RspPHIInBlk1);
}
// Here's where it becomes tricky: we should not merge if there are two
// _distinct_ backedge PHIs. We can't have a PHI that happens in both rsp
// and rax for example. We can only pick one location as the live-in.
OutLocs[2][0] = RaxPHIInBlk1;
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
// The above test sources correct machine-PHI-value from two places. Now
// try with one machine-PHI-value, but placed in two different locations
// on the backedge. Again, we can't merge a location here, there's no
// location that works on all paths.
OutLocs[0][0] = LiveInRsp;
OutLocs[1][0] = RspPHIInBlk1;
OutLocs[2][0] = LiveInRsp;
OutLocs[2][1] = RspPHIInBlk1;
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_FALSE(Result);
// Scatter various PHI values across the available locations. Only rbx (loc 2)
// has the right value in both backedges -- that's the loc that should be
// picked.
OutLocs[0][2] = LiveInRsp;
OutLocs[1][0] = RspPHIInBlk1;
OutLocs[1][1] = RaxPHIInBlk1;
OutLocs[1][2] = RbxPHIInBlk1;
OutLocs[2][0] = LiveInRsp;
OutLocs[2][1] = RspPHIInBlk1;
OutLocs[2][2] = RbxPHIInBlk1;
Result = pickVPHILoc(*MBB1, Var, VLiveOutIdx, OutLocsPtr, Preds);
EXPECT_TRUE(Result);
if (Result) {
EXPECT_EQ(*Result, RbxPHIInBlk1);
}
}
TEST_F(InstrRefLDVTest, vlocJoinDiamond) {
// entry
// / \
// br1 br2
// \ /
// ret
setupDiamondBlocks();
ASSERT_TRUE(MTracker->getNumLocs() == 1);
LocIdx RspLoc(0);
Register RAX = getRegByName("RAX");
LocIdx RaxLoc = MTracker->lookupOrTrackRegister(RAX);
unsigned EntryBlk = 0, Br2Blk = 2, RetBlk = 3;
ValueIDNum LiveInRsp(EntryBlk, 0, RspLoc);
ValueIDNum LiveInRax(EntryBlk, 0, RaxLoc);
ValueIDNum RspPHIInBlkBr2Blk(Br2Blk, 0, RspLoc);
ValueIDNum RspPHIInBlkRetBlk(RetBlk, 0, RspLoc);
DebugVariable Var(FuncVariable, None, nullptr);
DbgValueProperties EmptyProps(EmptyExpr, false);
SmallVector<DbgValue, 32> VLiveOuts;
VLiveOuts.resize(4, DbgValue(EmptyProps, DbgValue::Undef));
InstrRefBasedLDV::LiveIdxT VLiveOutIdx;
VLiveOutIdx[MBB0] = &VLiveOuts[0];
VLiveOutIdx[MBB1] = &VLiveOuts[1];
VLiveOutIdx[MBB2] = &VLiveOuts[2];
VLiveOutIdx[MBB3] = &VLiveOuts[3];
SmallPtrSet<const MachineBasicBlock *, 8> AllBlocks;
AllBlocks.insert(MBB0);
AllBlocks.insert(MBB1);
AllBlocks.insert(MBB2);
AllBlocks.insert(MBB3);
SmallVector<const MachineBasicBlock *, 2> Preds;
for (const auto *Pred : MBB3->predecessors())
Preds.push_back(Pred);
SmallSet<DebugVariable, 4> AllVars;
AllVars.insert(Var);
// vlocJoin is here to propagate incoming values, and eliminate PHIs. Start
// off by propagating a value into the merging block, number 3.
DbgValue JoinedLoc = DbgValue(3, EmptyProps, DbgValue::NoVal);
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
bool Result = vlocJoin(*MBB3, VLiveOutIdx, AllBlocks, JoinedLoc);
EXPECT_TRUE(Result); // Output locs should have changed.
EXPECT_EQ(JoinedLoc.Kind, DbgValue::Def);
EXPECT_EQ(JoinedLoc.ID, LiveInRsp);
// And if we did it a second time, leaving the live-ins as it was, then
// we should report no change.
Result = vlocJoin(*MBB3, VLiveOutIdx, AllBlocks, JoinedLoc);
EXPECT_FALSE(Result);
// If the live-in variable values are different, but there's no PHI placed
// in this block, then just pick a location. It should be the first (in RPO)
// predecessor to avoid being a backedge.
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(LiveInRax, EmptyProps, DbgValue::Def);
JoinedLoc = DbgValue(3, EmptyProps, DbgValue::NoVal);
Result = vlocJoin(*MBB3, VLiveOutIdx, AllBlocks, JoinedLoc);
EXPECT_TRUE(Result);
EXPECT_EQ(JoinedLoc.Kind, DbgValue::Def);
// RPO is blocks 0 2 1 3, so LiveInRax is picked as the first predecessor
// of this join.
EXPECT_EQ(JoinedLoc.ID, LiveInRax);
// No tests for whether vlocJoin will pass-through a variable with differing
// expressions / properties. Those can only come about due to assignments; and
// for any assignment at all, a PHI should have been placed at the dominance
// frontier. We rely on the IDF calculator being accurate (which is OK,
// because so does the rest of LLVM).
// Try placing a PHI. With differing input values (LiveInRsp, LiveInRax),
// this PHI should not be eliminated.
JoinedLoc = DbgValue(3, EmptyProps, DbgValue::VPHI);
Result = vlocJoin(*MBB3, VLiveOutIdx, AllBlocks, JoinedLoc);
// Expect no change.
EXPECT_FALSE(Result);
EXPECT_EQ(JoinedLoc.Kind, DbgValue::VPHI);
// This should not have been assigned a fixed value.
EXPECT_EQ(JoinedLoc.ID, ValueIDNum::EmptyValue);
EXPECT_EQ(JoinedLoc.BlockNo, 3);
// Try a simple PHI elimination. Put a PHI in block 3, but LiveInRsp on both
// incoming edges. Re-load in and out-locs with unrelated values; they're
// irrelevant.
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
JoinedLoc = DbgValue(3, EmptyProps, DbgValue::VPHI);
Result = vlocJoin(*MBB3, VLiveOutIdx, AllBlocks, JoinedLoc);
EXPECT_TRUE(Result);
EXPECT_EQ(JoinedLoc.Kind, DbgValue::Def);
EXPECT_EQ(JoinedLoc.ID, LiveInRsp);
// If the "current" live-in is a VPHI, but not a VPHI generated in the current
// block, then it's the remains of an earlier value propagation. We should
// value propagate through this merge. Even if the current incoming values
// disagree, because we've previously determined any VPHI here is redundant.
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(LiveInRax, EmptyProps, DbgValue::Def);
JoinedLoc = DbgValue(2, EmptyProps, DbgValue::VPHI);
Result = vlocJoin(*MBB3, VLiveOutIdx, AllBlocks, JoinedLoc);
EXPECT_TRUE(Result);
EXPECT_EQ(JoinedLoc.Kind, DbgValue::Def);
EXPECT_EQ(JoinedLoc.ID, LiveInRax); // from block 2
// The above test, but test that we will install one value-propagated VPHI
// over another.
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(0, EmptyProps, DbgValue::VPHI);
JoinedLoc = DbgValue(2, EmptyProps, DbgValue::VPHI);
Result = vlocJoin(*MBB3, VLiveOutIdx, AllBlocks, JoinedLoc);
EXPECT_TRUE(Result);
EXPECT_EQ(JoinedLoc.Kind, DbgValue::VPHI);
EXPECT_EQ(JoinedLoc.BlockNo, 0);
// We shouldn't eliminate PHIs when properties disagree.
DbgValueProperties PropsWithIndirect(EmptyExpr, true);
VLiveOuts[1] = DbgValue(LiveInRsp, EmptyProps, DbgValue::Def);
VLiveOuts[2] = DbgValue(LiveInRsp, PropsWithIndirect, DbgValue::Def);
JoinedLoc = DbgValue(3, EmptyProps, DbgValue::VPHI);
Result = vlocJoin(*