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/*========================== begin_copyright_notice ============================
Copyright (C) 2017-2021 Intel Corporation
SPDX-License-Identifier: MIT
============================= end_copyright_notice ===========================*/
//
// GenXLiveness is an analysis that contains the liveness information for the
// values in the code. See the comment at the top of GenXLiveness.h for further
// details.
//
//===----------------------------------------------------------------------===//
#include "GenXLiveness.h"
#include "GenX.h"
#include "GenXBaling.h"
#include "GenXIntrinsics.h"
#include "GenXNumbering.h"
#include "GenXSubtarget.h"
#include "GenXTargetMachine.h"
#include "GenXUtil.h"
#include "vc/GenXOpts/GenXAnalysis.h"
#include "vc/Utils/GenX/GlobalVariable.h"
#include "vc/Utils/GenX/InternalMetadata.h"
#include "vc/Utils/GenX/PredefinedVariable.h"
#include "vc/Utils/GenX/RegCategory.h"
#include "llvm/GenXIntrinsics/GenXMetadata.h"
#include "Probe/Assertion.h"
#include "llvmWrapper/IR/InstrTypes.h"
#include "llvmWrapper/IR/Instructions.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/Debug.h"
#define DEBUG_TYPE "GENX_LIVENESS"
#include <unordered_set>
using namespace llvm;
using namespace genx;
void GenXLiveness::getAnalysisUsage(AnalysisUsage &AU) {
AU.addRequired<TargetPassConfig>();
AU.setPreservesAll();
}
/***********************************************************************
* runOnFunctionGroup : do nothing
*/
bool GenXLiveness::runOnFunctionGroup(FunctionGroup &ArgFG)
{
LLVM_DEBUG(dbgs() << "init GenXLiveness\n");
FG = &ArgFG;
Subtarget = &getAnalysis<TargetPassConfig>()
.getTM<GenXTargetMachine>()
.getGenXSubtarget();
DL = &ArgFG.getModule()->getDataLayout();
return false;
}
/***********************************************************************
* releaseMemory: clear the GenXLiveness
*/
void GenXLiveness::releaseMemory() {
LLVM_DEBUG(dbgs() << "releaseMemory for GenXLivness\n");
while (!LiveRangeMap.empty()) {
LiveRange *LR = begin()->second;
for (auto i = LR->value_begin(), e = LR->value_end(); i != e; ++i) {
SimpleValue V = *i;
LiveRangeMap.erase(V);
}
delete LR;
}
FG = 0;
CG.reset();
for (auto i = UnifiedRets.begin(), e = UnifiedRets.end(); i != e; ++i)
i->second->deleteValue();
UnifiedRets.clear();
UnifiedRetToFunc.clear();
ArgAddressBaseMap.clear();
BaseToArgAddrMap.clear();
}
static vc::RegCategory getCategoryForPredefinedVariable(SimpleValue SV) {
const vc::RegCategory Category =
llvm::StringSwitch<vc::RegCategory>(SV.getValue()->getName())
.Case(vc::PredefVar::BSSName, vc::RegCategory::Surface)
.Case(vc::PredefVar::ImplicitArgsBufferName, vc::RegCategory::General)
.Case(vc::PredefVar::LocalIDBufferName, vc::RegCategory::General)
.Default(vc::RegCategory::None);
IGC_ASSERT_MESSAGE(Category != vc::RegCategory::None,
"Unhandled predefined variable");
return Category;
}
static bool isPredefinedVariable(SimpleValue SV) {
Value *V = SV.getValue();
IGC_ASSERT_MESSAGE(V, "Expected value");
bool Result = vc::PredefVar::isPV(*V);
if (Result)
IGC_ASSERT_MESSAGE(SV.getIndex() == 0,
"Expected single simple value for predefined variable");
return Result;
}
/***********************************************************************
* getDefaultCategory: get default category based on SimpleValue
*
* The default category is PREDICATE for i1 or a vector of i1,
* Surface for BSSName predefined variable or GENERAL for anything else.
*/
static vc::RegCategory getDefaultCategory(SimpleValue SV) {
if (isPredefinedVariable(SV))
return getCategoryForPredefinedVariable(SV);
Type *Ty =
IndexFlattener::getElementType(SV.getValue()->getType(), SV.getIndex());
if (Ty->getScalarType()->isIntegerTy(1))
return vc::RegCategory::Predicate;
return vc::RegCategory::General;
}
/***********************************************************************
* setLiveRange : add a SimpleValue to a LiveRange
*
* This:
* 1. adds the SimpleValue to the LiveRange's value list;
* 2. sets the SimpleValue's entry in the map to point to the LiveRange.
*/
void GenXLiveness::setLiveRange(SimpleValue V, LiveRange *LR)
{
IGC_ASSERT_MESSAGE(
LiveRangeMap.find(V) == end(),
"Attempting to set LiveRange for Value that already has one");
LLVM_DEBUG(dbgs() << "Setting LiveRange " << *LR << " for SV: " << V << "\n");
LR->addValue(V);
LiveRangeMap[V] = LR;
LR->setAlignmentFromValue(
*DL, V, Subtarget ? Subtarget->getGRFByteSize() : defaultGRFByteSize);
}
/***********************************************************************
* setAlignmentFromValue : set a live range's alignment from a value
*/
void LiveRange::setAlignmentFromValue(const DataLayout &DL, const SimpleValue V,
const unsigned GRFWidth) {
LLVM_DEBUG(dbgs() << "Setting Alignment for value " << V);
const unsigned AlignInBytes = getValueAlignmentInBytes(*(V.getValue()), DL);
const unsigned LogByteAlign = Log2_32(AlignInBytes);
// Set max alignment to GRF.
const unsigned MaxLogAlign =
genx::getLogAlignment(VISA_Align::ALIGN_GRF, GRFWidth);
const unsigned SaturatedLogAlign = std::clamp(LogByteAlign, 0u, MaxLogAlign);
unsigned ResultAlign = ceilLogAlignment(SaturatedLogAlign, GRFWidth);
LLVM_DEBUG(dbgs() << " result: " << ResultAlign << "\n");
setLogAlignment(ResultAlign);
}
/***********************************************************************
* rebuildCallGraph : rebuild GenXLiveness's call graph
*/
void GenXLiveness::rebuildCallGraph()
{
LLVM_DEBUG(dbgs() << "Rebuilding CallGraph\n");
CG = std::make_unique<genx::CallGraph>(FG);
CG->build(this);
}
/***********************************************************************
* buildSubroutineLRs : build the subroutine LRs
*
* If the FunctionGroup has subroutines, then each one (each Function other
* than the head one) gets a "subroutine LR", giving the live range
* of the whole subroutine plus any other subroutines it can call.
* Then, when building a real live range later, if it goes over a call,
* we can add the subroutine LR.
*
* The subroutine LR has weak liveness, as that's what we want to add to
* anything live over a call to the subroutine.
*/
void GenXLiveness::buildSubroutineLRs()
{
LLVM_DEBUG(dbgs() << "BuildingSubroutineLRs\n");
if (FG->size() == 1) {
LLVM_DEBUG(dbgs() << "No subroutines\n");
return; // no subroutines
}
// Build a call graph for the FunctionGroup. It is acyclic because there is
// no recursion.
rebuildCallGraph();
// Depth-first walk the graph to propagate live ranges upwards.
visitPropagateSLRs(FG->getHead());
}
/***********************************************************************
* visitPropagateSLRs : visit a callgraph node to propagate subroutine LR
*
* This is recursive.
*/
LiveRange *GenXLiveness::visitPropagateSLRs(Function *F)
{
LLVM_DEBUG(dbgs() << "VisitPropagateSLRs begin\n");
LiveRange *LR = getOrCreateLiveRange(F);
// Add a segment for just this function.
LR->push_back(Segment(Numbering->getNumber(F),
Numbering->getNumber(F->back().getTerminator()) + 1, Segment::WEAK));
// For each child...
genx::CallGraph::Node *N = CG->getNode(F);
for (auto i = N->begin(), e = N->end(); i != e; ++i) {
// Visit the child to calculate its LR.
LiveRange *ChildLR = visitPropagateSLRs(i->Call->getCalledFunction());
// Merge it into ours.
LR->addSegments(ChildLR);
}
LR->sortAndMerge();
LLVM_DEBUG(dbgs() << "VisitPropagateSLRs return: " << *LR << "\n");
return LR;
}
/***********************************************************************
* buildLiveRange : build live range for one value (arg or non-baled inst)
*
* For an aggregate value, each element's live range is built separately, even
* though they are almost identical. They are not exactly identical,
* differing at the def if it is the return value of a call, and at a use
* that is a call arg.
*/
void GenXLiveness::buildLiveRange(Value *V)
{
LLVM_DEBUG(dbgs() << "Building LiveRange for :" << *V << "\n");
Type *Ty = V->getType();
if (!Ty->isAggregateType()) {
LLVM_DEBUG(dbgs() << "It is not aggregate, build for one\n");
buildLiveRange(SimpleValue(V));
return;
}
for (unsigned i = 0, e = IndexFlattener::getNumElements(Ty); i != e; ++i) {
LLVM_DEBUG(dbgs() << "Bulding for aggregate Index " << i << " from " << e
<< "\n");
buildLiveRange(SimpleValue(V, i));
}
}
/***********************************************************************
* buildLiveRange : build live range for one SimpleValue
*
* rebuildLiveRange : rebuild live range for a LiveRange struct
*
* The BBs[] array, one entry per basic block, is temporarily used here to
* store the live range for the value within that block. We start by
* registering the short live range for the definition, then, for each use,
* create a live range in the use's block then recursively scan back
* through predecessors until we meet a block where there is already a
* live range. This is guaranteed to terminate because of the dominance
* property of SSA.
*
* See Appel "Modern Compiler Implementation in C" 19.6.
*
* rebuildLiveRange can be called from later passes to rebuild the segments
* for a particular live range. If used after coalescing, the live range might
* have more than one value, in which case segments are added for each value
* and then merged. Thus we assume that, after whatever code change a pass made
* to require rebuilding the live range, the coalesced values can still be
* validly coalesced, without having any way of checking that.
*
*/
LiveRange *GenXLiveness::buildLiveRange(SimpleValue V)
{
LLVM_DEBUG(dbgs() << "Building LiveRange for SimpleValue: " << V << "\n");
LiveRange *LR = getOrCreateLiveRange(V);
rebuildLiveRange(LR);
LLVM_DEBUG(dbgs() << "Building LiveRange for SimpleValue return: " << *LR
<< "\n");
return LR;
}
void GenXLiveness::rebuildLiveRange(LiveRange *LR)
{
LLVM_DEBUG(dbgs() << "Rebuilding LiveRange: " << *LR << "\n");
LR->getOrDefaultCategory();
LR->Segments.clear();
for (auto vi = LR->value_begin(), ve = LR->value_end(); vi != ve; ++vi)
rebuildLiveRangeForValue(LR, *vi);
LR->sortAndMerge();
LLVM_DEBUG(dbgs() << "Rebuilding LiveRange result: " << *LR << "\n");
}
void GenXLiveness::rebuildLiveRangeForValue(LiveRange *LR, SimpleValue SV)
{
LLVM_DEBUG(dbgs() << "rebuilding LiveRange: " << *LR
<< " for SimpleValue: " << SV << "\n");
Value *V = SV.getValue();
// This value is a global variable. Its live range is the entire kernel.
if (vc::getUnderlyingGlobalVariable(V)) {
LR->push_back(0, Numbering->getLastNumber());
LLVM_DEBUG(dbgs() << "It is global value, rebuilded LR: " << *LR << "\n");
return;
}
std::map<BasicBlock *, Segment> BBRanges;
if (auto Func = isUnifiedRet(V)) {
// This value is the unified return value of the function Func. Its live
// range is from the call to where its post-copy would go just afterwards
// for each call site, also from the site of the pre-copy to the return
// instruction.
LLVM_DEBUG(dbgs() << "It is UnifiedRet\n");
for (auto *U: Func->users()) {
if (auto *CI = genx::checkFunctionCall(U, Func)) {
LR->push_back(Numbering->getNumber(CI),
Numbering->getRetPostCopyNumber(CI, SV.getIndex()));
LLVM_DEBUG(dbgs() << "Adding Segment: " << *LR << "\n");
}
}
for (auto fi = Func->begin(), fe = Func->end(); fi != fe; ++fi)
if (auto RI = dyn_cast<ReturnInst>(fi->getTerminator())) {
LR->push_back(Numbering->getRetPreCopyNumber(RI, SV.getIndex()),
Numbering->getNumber(RI));
LLVM_DEBUG(dbgs() << "It is ReturnInst, Adding Segment: " << *LR
<< "\n");
}
LLVM_DEBUG(dbgs() << "It is UnifiedRet, return LR: " << *LR << "\n");
return;
}
// Mark the value as live and then almost immediately dead again at the
// point where it is defined.
unsigned StartNum = 0, EndNum = 0;
Function *Func = 0;
auto Arg = dyn_cast<Argument>(V);
BasicBlock *BB = nullptr;
if (Arg) {
Func = Arg->getParent();
StartNum = Numbering->getNumber(Func);
EndNum = StartNum + 1;
BB = &Func->front();
} else if (auto Phi = dyn_cast<PHINode>(V)) {
// Phi node. Treat as defined at the start of the block.
EndNum = Numbering->getNumber(Phi) + 1;
BB = Phi->getParent();
StartNum = Numbering->getNumber(BB);
// For a phi node, we also need to register an extra little live range at
// the end of each predecessor, from where we will insert a copy to the
// end. This is done lower down in this function.
} else {
StartNum = Numbering->getNumber(V);
auto Inst = cast<Instruction>(V);
BB = Inst->getParent();
auto CI = dyn_cast<CallInst>(V);
if (CI) {
if (!GenXIntrinsic::isAnyNonTrivialIntrinsic(V)) {
// For the return value from a call, move the definition point to the ret
// post-copy slot after the call, where the post-copy will be inserted if
// it fails to be coalesced with the function's unified return value.
StartNum = Numbering->getRetPostCopyNumber(CI, SV.getIndex());
}
}
EndNum = StartNum + 1;
if (CI && getTwoAddressOperandNum(CI)) {
// Two address op. Move the definition point one earlier, to where
// GenXCoalescing will need to insert a copy if coalescing fails.
--StartNum;
}
}
BBRanges[BB] = Segment(StartNum, EndNum);
// The stack for predecessors that need to be processed:
std::vector<BasicBlock *> Stack;
// Process each use.
for (Value::use_iterator i = V->use_begin(), e = V->use_end();
i != e; ++i) {
BasicBlock *BB = nullptr;
Instruction *user = cast<Instruction>(i->getUser());
unsigned Num;
if (PHINode *Phi = dyn_cast<PHINode>(user)) {
// Use in a phi node. We say that the use is where the phi copy will be
// placed in the predecessor block.
BB = Phi->getIncomingBlock(*i);
Num = Numbering->getPhiNumber(Phi, BB);
} else {
// Normal use.
// For live range purposes, an instruction is considered to be at the
// same place as the head of its bale. We need to use getBaleHead to
// ensure that we consider it to be there.
Instruction *UserHead = Baling->getBaleHead(user);
BB = UserHead->getParent();
Num = Numbering->getNumber(UserHead);
if (auto CI = dyn_cast<CallInst>(user)) {
if (CI->isInlineAsm() || IGCLLVM::isIndirectCall(*CI))
Num = Numbering->getNumber(UserHead);
else {
switch (vc::getAnyIntrinsicID(CI)) {
case GenXIntrinsic::not_any_intrinsic:
// Use as a call arg. We say that the use is at the arg pre-copy
// slot, where the arg copy will be inserted in coalescing. This
// assumes that the copies will be in the same order as args in the
// call, with struct elements in order too.
Num = Numbering->getArgPreCopyNumber(CI, i->getOperandNo(),
SV.getIndex());
break;
default:
if (auto OpndNum = getTwoAddressOperandNum(CI);
OpndNum && *OpndNum == i->getOperandNo()) {
// The use is the two address operand in a two address op. Move
// the use point one earlier, to where GenXCoalescing will need
// to insert a copy if coalescing fails. If there is any other
// use of this value in the same bale, that will not have its use
// point one number earlier. The unnecessary interference that
// would cause is fixed in the way that twoAddrInterfere()
// detects interference.
--Num;
}
break;
case GenXIntrinsic::genx_simdcf_goto:
// Use in a goto. Treat it as at the branch, as GenXCisaBuilder
// writes the goto just before the branch, after any intervening IR.
Num = Numbering->getNumber(CI->getParent()->getTerminator());
break;
}
}
} else if (auto RI = dyn_cast<ReturnInst>(user)) {
// Use in a return. We say that the use is where the ret value
// pre-copy will be inserted in coalescing. This assumes that the
// copies will be in the same order as the struct elements in the
// return value.
Num = Numbering->getRetPreCopyNumber(RI, SV.getIndex());
}
}
auto BBRange = &BBRanges[BB];
if (BBRange->getEnd()) {
// There is already a live range in this block. Extend it if
// necessary. No need to scan back from here, so we're done with
// this use.
if (BBRange->getEnd() < Num)
BBRange->setEnd(Num);
continue;
}
// Add a new live range from the start of this block, and remember the
// range of blocks that contain a live range (so we don't have to scan
// all of them at the end).
*BBRange = Segment(Numbering->getNumber(BB), Num);
// Push this block's predecessors onto the stack.
std::copy(pred_begin(BB), pred_end(BB), std::back_inserter(Stack));
// Process stack until empty.
while (Stack.size()) {
BB = Stack.back();
Stack.pop_back();
BBRange = &BBRanges[BB];
auto BBNum = Numbering->getBBNumber(BB);
if (BBRange->getEnd()) {
// There is already a live range in this block. Extend it to the end.
// No need to scan back from here.
BBRange->setEnd(BBNum->EndNumber);
continue;
}
// Add a new live range through the whole of this block, and remember the
// range of blocks that contain a live range (so we don't have to scan
// all of them at the end).
BBRange->setStartEnd(Numbering->getNumber(BB), BBNum->EndNumber);
// Push this block's predecessors onto the stack.
std::copy(pred_begin(BB), pred_end(BB), std::back_inserter(Stack));
}
}
// Now we can build the live range.
for (auto bri = BBRanges.begin(), bre = BBRanges.end(); bri != bre; ++bri) {
auto BBRange = &bri->second;
LR->push_back(*BBRange);
}
if (PHINode *Phi = dyn_cast<PHINode>(V)) {
// For a phi node, we also need to register an extra little live range at
// the end of each predecessor, from where we will insert a copy to the
// end.
for (unsigned i = 0, e = Phi->getNumIncomingValues(); i != e; ++i) {
auto Pred = Phi->getIncomingBlock(i);
auto BBNum = Numbering->getBBNumber(Pred);
LR->push_back(Segment(Numbering->getPhiNumber(Phi, Pred),
BBNum->EndNumber, Segment::PHICPY));
}
}
LR->sortAndMerge();
if (CG) {
// Check if the live range crosses any call instruction. If so, add the
// appropriate subroutine live range.
bool NeedSort = false;
auto N = CG->getNode(Func);
for (auto i = N->begin(), e = N->end(); i != e; ++i) {
auto E = &*i;
// See if this call is in a segment of the LR.
auto Seg = LR->find(E->Number);
if (Seg != LR->end() && Seg->getStart() <= E->Number && Seg->getEnd() > E->Number) {
// Yes it is. Merge the subroutine LR of the callee into our LR.
if (!E->Call->getCalledFunction()->hasFnAttribute("CMStackCall"))
LR->addSegments(getLiveRange(E->Call->getCalledFunction()));
NeedSort = true;
}
}
if (NeedSort)
LR->sortAndMerge();
}
if (Arg) {
// For a function arg, for each call site, add a segment from the arg
// pre-copy site, the point just before the call at which it will be copied
// into, up to the call. We assume that any copies before the call
// inserted by coalescing will be in the obvious order of args and elements
// within args.
Function *F = Arg->getParent();
if (*FG->begin() != F) { // is a subroutine
for (auto *U : F->users()) {
if (auto *CI = genx::checkFunctionCall(U, F))
LR->push_back(Numbering->getArgPreCopyNumber(CI, Arg->getArgNo(),
SV.getIndex()),
Numbering->getNumber(CI));
}
}
}
}
void GenXLiveness::removeBale(Bale &B) {
LLVM_DEBUG(dbgs() << "Removing Bale: " << B << "\n");
for (auto bi = B.begin(), be = B.end(); bi != be; ++bi)
removeValue(bi->Inst);
}
/***********************************************************************
* removeValue : remove the supplied value from its live range, and delete
* the range if it now has no values
*
* removeValueNoDelete : same, but do not delete the LR if it is now
* valueless
*
* Calling this with a value that does not have a live range is silently
* ignored.
*/
void GenXLiveness::removeValue(Value *V)
{
LLVM_DEBUG(dbgs() << "Removing Value: " << *V << "\n");
for (unsigned i = 0, e = IndexFlattener::getNumElements(V->getType()); i != e; ++i)
removeValue(SimpleValue(V, i));
}
void GenXLiveness::removeValue(SimpleValue V)
{
LLVM_DEBUG(dbgs() << "Removing SimpleValue: " << V << "\n");
LiveRange *LR = removeValueNoDelete(V);
if (LR && !LR->Values.size()) {
// V was the only value in LR. Remove LR completely.
delete LR;
}
}
LiveRange *GenXLiveness::removeValueNoDelete(SimpleValue V)
{
LiveRangeMap_t::iterator i = LiveRangeMap.find(V);
if (i == end())
return nullptr;
LiveRange *LR = i->second;
LiveRangeMap.erase(i);
// Remove V from LR.
unsigned j;
for (j = 0; LR->Values[j].get() != V; ++j) {
IGC_ASSERT(j != LR->Values.size());
}
if (&LR->Values[j] != &LR->Values.back())
LR->Values[j] = LR->Values.back();
LR->Values.pop_back();
return LR;
}
/***********************************************************************
* removeValuesNoDelete : remove all values from the live range, but do not
* delete the LR
*/
void GenXLiveness::removeValuesNoDelete(LiveRange *LR)
{
LLVM_DEBUG(dbgs() << "Removing all Values in LR, not delete " << *LR << "\n");
for (auto vi = LR->value_begin(), ve = LR->value_end(); vi != ve; ++vi)
LiveRangeMap.erase(*vi);
LR->value_clear();
}
/***********************************************************************
* replaceValue : update liveness such that NewVal has OldVal's live range,
* and OldVal does not have one at all.
*/
void GenXLiveness::replaceValue(Value *OldVal, Value *NewVal)
{
LLVM_DEBUG(dbgs() << "Replace Values: from " << *OldVal << " to " << *NewVal
<< "\n");
for (unsigned i = 0, e = IndexFlattener::getNumElements(OldVal->getType());
i != e; ++i)
replaceValue(SimpleValue(OldVal, i), SimpleValue(NewVal, i));
}
void GenXLiveness::replaceValue(SimpleValue OldVal, SimpleValue NewVal)
{
LLVM_DEBUG(dbgs() << "Replace SimpleValues: from " << OldVal << " to "
<< NewVal << "\n");
LiveRangeMap_t::iterator i = LiveRangeMap.find(OldVal);
IGC_ASSERT(i != end());
LiveRange *LR = i->second;
LiveRangeMap.erase(i);
LiveRangeMap[NewVal] = LR;
unsigned j = 0;
IGC_ASSERT(!LR->Values.empty());
for (j = 0; LR->Values[j].get() != OldVal; ++j)
IGC_ASSERT(j != LR->Values.size());
LR->Values[j] = NewVal;
}
/***********************************************************************
* getOrCreateLiveRange : get live range for a value, creating if necessary
*/
LiveRange *GenXLiveness::getOrCreateLiveRange(SimpleValue V)
{
auto [i, isInserted] = LiveRangeMap.emplace(V, nullptr);
LLVM_DEBUG(dbgs() << "getOrCreateLiveRange for SimpleValue: " << V << " "
<< (isInserted ? "Inserted" : "Not inserted") << "\n");
LiveRange *LR = i->second;
if (!LR) {
// Newly created map entry. Create the LiveRange for it.
LR = new LiveRange;
LR->Values.push_back(V);
i->second = LR;
LR->setAlignmentFromValue(
*DL, V, Subtarget ? Subtarget->getGRFByteSize() : defaultGRFByteSize);
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
// Give the Value a name if it doesn't already have one.
if (!V.getValue()->getName().size()) {
std::string NameBuf;
StringRef Name = "arg";
if (auto Inst = dyn_cast<Instruction>(V.getValue())) {
unsigned IID = vc::getAnyIntrinsicID(V.getValue());
if (GenXIntrinsic::isAnyNonTrivialIntrinsic(IID)) {
// For an intrinsic call, use the intrinsic name after the
// final period.
NameBuf = GenXIntrinsic::getAnyName(IID, None);
Name = NameBuf;
size_t Period = Name.rfind('.');
if (Period != StringRef::npos)
Name = Name.slice(Period + 1, Name.size());
} else
Name = Inst->getOpcodeName();
}
V.getValue()->setName(Name);
}
#endif
LLVM_DEBUG(dbgs() << "Resulted LR: " << *LR << "\n");
return LR;
}
LiveRange *GenXLiveness::getOrCreateLiveRange(SimpleValue V,
vc::RegCategory Cat,
unsigned LogAlign) {
LLVM_DEBUG(dbgs() << "getOrCreateLiveRange with SimpleValue: " << V
<< " Category: " << vc::getRegCategoryName(Cat)
<< " LogAlign: " << LogAlign << "\n");
auto LR = getOrCreateLiveRange(V);
LR->setCategory(Cat);
LR->setLogAlignment(LogAlign);
LLVM_DEBUG(dbgs() << "getOrCreateLiveRange return: " << *LR << "\n");
return LR;
}
/***********************************************************************
* eraseLiveRange : get rid of live range for a Value, possibly multiple
* ones if it is an aggregate value
*/
void GenXLiveness::eraseLiveRange(Value *V)
{
LLVM_DEBUG(dbgs() << "Erasing LiveRange for Value: " << *V << "\n");
Type *Ty = V->getType();
if (!Ty->isAggregateType()) {
eraseLiveRange(SimpleValue(V));
return;
}
for (unsigned i = 0, e = IndexFlattener::getNumElements(Ty); i != e; ++i)
eraseLiveRange(SimpleValue(V, i));
}
/***********************************************************************
* eraseLiveRange : get rid of live range for a Value, if any
*/
void GenXLiveness::eraseLiveRange(SimpleValue V)
{
LLVM_DEBUG(dbgs() << "Erasing LiveRange for SimpleValue: " << V << "\n");
auto LR = getLiveRangeOrNull(V);
if (LR)
eraseLiveRange(LR);
}
/***********************************************************************
* eraseLiveRange : get rid of the specified live range, and remove its
* values from the map
*/
void GenXLiveness::eraseLiveRange(LiveRange *LR)
{
LLVM_DEBUG(dbgs() << "Erasing LiveRange: " << *LR << "\n");
for (auto vi = LR->value_begin(), ve = LR->value_end(); vi != ve; ++vi)
LiveRangeMap.erase(*vi);
delete LR;
}
/***********************************************************************
* getLiveRangeOrNull : get live range for value, or 0 if none
*
* The returned LiveRange pointer is valid only until the next time the
* live ranges are modified, including the case of coalescing.
*/
const LiveRange *GenXLiveness::getLiveRangeOrNull(SimpleValue V) const
{
LLVM_DEBUG(dbgs() << "Getting LiveRangeOrNull for: " << V);
auto i = LiveRangeMap.find(V);
if (i == end()) {
LLVM_DEBUG(dbgs() << " Not found, nullptr return\n");
return nullptr;
}
LLVM_DEBUG(dbgs() << " Found: " << *(i->second) << "\n");
return i->second;
}
LiveRange *GenXLiveness::getLiveRangeOrNull(SimpleValue V)
{
return const_cast<LiveRange*>(static_cast<const GenXLiveness*>(this)->getLiveRangeOrNull(V));
}
/***********************************************************************
* getLiveRange : get live range for value
*
* The returned LiveRange pointer is valid only until the next time the
* live ranges are modified, including the case of coalescing.
*/
LiveRange *GenXLiveness::getLiveRange(SimpleValue V)
{
LiveRange *LR = getLiveRangeOrNull(V);
IGC_ASSERT_MESSAGE(LR, "no live range found");
return LR;
}
/***********************************************************************
* getUnifiedRet : get/create unified return value for a function
*
* Returns already created unified value, or creates new one
* if there was no such.
*/
Value *GenXLiveness::getUnifiedRet(Function *F) {
auto *Ret = getUnifiedRetIfExist(F);
if (!Ret)
return createUnifiedRet(F);
return Ret;
}
Value *GenXLiveness::getUnifiedRetIfExist(Function *F) const {
auto RetIt = UnifiedRets.find(F);
if (RetIt == UnifiedRets.end())
return nullptr;
return RetIt->second;
}
/***********************************************************************
* createUnifiedRet : create unified return value for a function
*
* To allow all returns in a function and all results of calls to that
* function to use the same register, we have a dummy "unified return
* value".
*
* Cannot be called on a function with void return type.
*
* This also creates the LiveRange for the unified return value, or
* multiple ones if it is aggregate type, and sets the category to the same as
* in one of the return instructions.
*/
Value *GenXLiveness::createUnifiedRet(Function *F) {
IGC_ASSERT_MESSAGE(!F->isDeclaration(), "must be a function definition");
IGC_ASSERT_MESSAGE(UnifiedRets.find(F) == UnifiedRets.end(),
"Unified ret must not have been already created");
Type *Ty = F->getReturnType();
IGC_ASSERT(!Ty->isVoidTy());
auto URet = genx::createUnifiedRet(Ty, "", F->getParent());
// Find some return inst.
ReturnInst *Ret = nullptr;
for (auto fi = F->begin(), fe = F->end(); fi != fe; ++fi)
if ((Ret = dyn_cast<ReturnInst>(fi->getTerminator())))
break;
IGC_ASSERT_MESSAGE(Ret, "must find return instruction");
Value *RetVal = Ret->getOperand(0);
// Use the categories of its operand to set the categories of the unified
// return value.
for (unsigned AggrIdx = 0, NumElements = IndexFlattener::getNumElements(Ty);
AggrIdx != NumElements; ++AggrIdx) {
auto RetValSV = SimpleValue(RetVal, AggrIdx);
auto *RetValLR = getLiveRangeOrNull(RetValSV);
auto URetSV = SimpleValue(URet, AggrIdx);
auto Cat = RetValLR ? RetValLR->getOrDefaultCategory()
: getDefaultCategory(RetValSV);
getOrCreateLiveRange(URetSV)->setCategory(Cat);
}
UnifiedRets[F] = URet;
UnifiedRetToFunc[URet] = F;
return URet;
}
/***********************************************************************
* isUnifiedRet : test whether a value is a unified return value
*
* A unified ret value is a call instruction that is
* not attached to any BB, and is in the UnifiedRetFunc map.
*/
Function *GenXLiveness::isUnifiedRet(Value *V)
{
// Quick checks first.
auto Inst = dyn_cast<CallInst>(V);
if (!Inst)
return nullptr;
if (Inst->getParent())
return nullptr;
// Then map lookup.
auto i = UnifiedRetToFunc.find(V);
if (i == UnifiedRetToFunc.end())
return nullptr;
return i->second;
}
/***********************************************************************
* moveUnifiedRet : move a function's unified return value to another function
*
* This is used when replacing a function with a new one in GenXArgIndirection.
*/
void GenXLiveness::moveUnifiedRet(Function *OldF, Function *NewF)
{
auto i = UnifiedRets.find(OldF);
if (i == UnifiedRets.end())
return;
Value *UR = i->second;
UnifiedRets[NewF] = UR;
UnifiedRets.erase(i);
UnifiedRetToFunc[UR] = NewF;
}
/***********************************************************************
* find : given an instruction number, find a segment in a live range
*
* If the number is within a segment, or is just on its end point, that
* segment is returned. If the number is in a hole, the next segment
* after the hole is returned. If the number is before the first
* segment, the first segment is returned. If the number is after the
* last segment, end() is returned.
*/
LiveRange::iterator LiveRange::find(unsigned Pos)
{
size_t Len = size();
if (!Len)
return end();
if (Pos > Segments[Len - 1].getEnd())
return end();
iterator I = begin();
do {
size_t Mid = Len >> 1;
if (Pos <= I[Mid].getEnd())
Len = Mid;
else
I += Mid + 1, Len -= Mid + 1;
} while (Len);
IGC_ASSERT(I->getEnd() >= Pos);
return I;
}
/***********************************************************************
* getOrDefaultCategory : get category; if none, set default
*
* The default category is PREDICATE for i1 or a vector of i1, or GENERAL
* for anything else.
*/
vc::RegCategory LiveRange::getOrDefaultCategory() {
vc::RegCategory Cat = getCategory();
if (Cat != vc::RegCategory::None)
return Cat;
IGC_ASSERT(!value_empty());
Cat = getDefaultCategory(*value_begin());
setCategory(Cat);
return Cat;
}
/***********************************************************************
* interfere : check whether two live ranges interfere
*
* Two live ranges interfere if there is a segment from each that overlap
* and they are considered to cause interference by
* checkIfOverlappingSegmentsInterfere below.
*/
bool GenXLiveness::interfere(LiveRange *LR1, LiveRange *LR2) {
if (CoalescingDisabled)
return true;
return getSingleInterferenceSites(LR1, LR2, nullptr);
}
/***********************************************************************
* twoAddrInterfere : check whether two live ranges interfere, allowing for
* single number interference sites at two address ops
*
* Return: true if they interfere
*
* Two live ranges interfere if there is a segment from each that overlap
* and are not both weak.
*
* But, if each interfering segment is a single number that is the precopy
* site of a two address op, and the result of the two address op is in one LR
* and the two address operand is in the other, then that is not counted as
* interference.
*
* That provision allows for coalescing at a two address op where the two
* address operand has already been copy coalesced with, or is the same value
* as, a different operand in the same bale, as follows:
*
* Suppose the two address op a has number N, and it has two address operand b
* and some other operand c in the same bale:
*
* N-1: (space for precopy)
* N: a = op(b, c)
*
* with live ranges
* a:[N-1,..)
* b:[..,N-1)
* c:[..,N)
*
* Then a and b can coalesce.
*
* But suppose b and c are the same value, or had previously been copy coalesced.
* Then we have live ranges
* a:[N-1,..)
* b,c:[..,N)
*
* and a and b now interfere needlessly.
*
* This function is called on an attempt to coalesce a and b (or rather the
* live range containing a and the live range containing b). In it, we see
* that there is a single number segment of interference [N-1,N), where a is
* the result and b is the two address operand of the two address op at N. Thus
* we discount that segment of interference, and a and b can still coalesce.
*
* Note that this formulation allows for there to be multiple such sites because
* of multiple two address results being already coalesced together through phi
* nodes.
*/
bool GenXLiveness::twoAddrInterfere(LiveRange *LR1, LiveRange *LR2) {
if (CoalescingDisabled)
return true;
SmallVector<unsigned, 4> Sites;
if (getSingleInterferenceSites(LR1, LR2, &Sites))
return true; // interferes, not just single number sites
if (Sites.empty())
return false; // does not interfere at all
// Put the single number sites in a set.
SmallSet<unsigned, 4> SitesSet;
LLVM_DEBUG(dbgs() << "got single number interference sites:");
for (auto i = Sites.begin(), e = Sites.end(); i != e; ++i) {
LLVM_DEBUG(dbgs() << " " << *i);
SitesSet.insert(*i);
}
LLVM_DEBUG(dbgs() << "\nbetween:\n" << *LR1 << "\n" << *LR2 << "\n");
Sites.clear();
// Check each def in LR1 and LR2 for being a two address op that causes us to
// discount a single number interference site.
for (auto LR = LR1, OtherLR = LR2; LR;
LR = LR == LR1 ? LR2 : nullptr, OtherLR = LR1) {
for (auto vi = LR->value_begin(), ve = LR->value_end(); vi != ve; ++vi) {
auto CI = dyn_cast<CallInst>(vi->getValue());
if (!CI)
continue;
auto OperandNum = getTwoAddressOperandNum(CI);
if (!OperandNum)
continue;
// Got a two addr op. Check whether the two addr operand is in the other
// LR.
if (getLiveRangeOrNull(CI->getOperand(*OperandNum)) != OtherLR)
continue;
// Discount the single number interference site here, if there is one.
SitesSet.erase(getNumbering()->getNumber(CI) - 1);
}
}
// If we have discounted all sites, then there is no interference.
return !SitesSet.empty();
}
/***********************************************************************
* getSingleInterferenceSites : check whether two live ranges interfere,
* returning single number interference sites
*
* Enter: LR1, LR2 = live ranges to check
* Sites = vector in which to store single number interference sites,
* or 0 if we do not want to collect them
*
* Return: true if the live ranges interfere other than as reflected in Sites
*
* Two live ranges interfere if there is a segment from each that overlap
* and are not both weak.
*
* If Sites is 0 (the caller does not want the Sites list), then the function
* returns true if there is any interference.
*
* If Sites is not 0, then any interference in a single number segment, for
* example [19,20), causes the start number to be pushed into Sites. The
* function returns true only if there is interference that cannot be described
* in Sites.
*/
bool GenXLiveness::getSingleInterferenceSites(LiveRange *LR1, LiveRange *LR2,
SmallVectorImpl<unsigned> *Sites)
{
// Swap if necessary to make LR1 the one with more segments.
if (LR1->size() < LR2->size())
std::swap(LR1, LR2);
auto Idx2 = LR2->begin(), End2 = LR2->end();
// Find segment in LR1 that contains or is the next after the start
// of the first segment in LR2, including the case that the start of
// the LR2 segment abuts the end of the LR1 segment.
auto Idx1 = LR1->find(Idx2->getStart()), End1 = LR1->end();
if (Idx1 == End1)
return false;
for (;;) {
// Check for overlap.
if (Idx1->getStart() < Idx2->getStart()) {
if (Idx1->getEnd() > Idx2->getStart())
if (checkIfOverlappingSegmentsInterfere(LR1, Idx1, LR2, Idx2)) {
// Idx1 overlaps Idx2. Check if it is a single number overlap that can
// be pushed into Sites.
if (!Sites || Idx1->getEnd() != Idx2->getStart() + 1)
return true;
Sites->push_back(Idx2->getStart());
}
} else {
if (Idx1->getStart() < Idx2->getEnd())
if (checkIfOverlappingSegmentsInterfere(LR1, Idx1, LR2, Idx2)) {
// Idx2 overlaps Idx1. Check if it is a single number overlap that can
// be pushed into Sites.
if (!Sites || Idx2->getEnd() != Idx1->getStart() + 1)
return true;
Sites->push_back(Idx1->getStart());
}
}
// Advance whichever one has the lowest End.
if (Idx1->getEnd() < Idx2->getEnd()) {
if (++Idx1 == End1)
return false;
} else {
if (++Idx2 == End2)
return false;
}
}
}
/***********************************************************************
* checkIfOverlappingSegmentsInterfere : given two segments that have been
* shown to overlap, check whether their strengths make them interfere
*
* If both segments are weak, they do not interfere.
*
* Interference between a normal segment in one LR and a phicpy segment in the
* other LR is ignored, as long as the phicpy segment relates to a phi incoming
* where the phi node is in the LR with the phicpy segment and the incoming
* value is in the LR with the strong segment. This is used to avoid
* unnecessary interference for a phi incoming through a critical edge, where
* the incoming is likely to be used in the other successor as well.
*/
bool GenXLiveness::checkIfOverlappingSegmentsInterfere(
LiveRange *LR1, Segment *S1, LiveRange *LR2, Segment *S2)
{
if (S1->isWeak() && S2->isWeak())
return false; // both segments weak
if (S2->Strength == Segment::PHICPY) {
// Swap so that if either segment is phicpy, then it is S1 for the check
// below.
std::swap(LR1, LR2);
std::swap(S1, S2);
}
if (S1->Strength != Segment::PHICPY)
return true;
// S1 is phicpy. If its corresponding phi cpy insertion point is for a phi
// node in LR1 and an incoming in LR2, then this does not cause interference.
auto PhiIncoming = Numbering->getPhiIncomingFromNumber(S1->getStart());
auto PhiFound = std::find_if(
PhiIncoming.begin(), PhiIncoming.end(), [LR1, this](auto It) {
PHINode *Phi = It.first;
IGC_ASSERT_MESSAGE(Phi, "phi incoming not found");
return getLiveRange(Phi) == LR1;
});
if (PhiFound == PhiIncoming.end())
return true; // phi not in LR1, interferes
PHINode *Phi = PhiFound->first;
unsigned IncomingBBIndex = PhiFound->second;
if (getLiveRangeOrNull(Phi->getIncomingValue(IncomingBBIndex)) != LR2)
return true; // phi incoming not in LR2, interferes
// Conditions met -- does not cause interference.
return false;
}
/***********************************************************************
* coalesce : coalesce two live ranges that do not interfere
*
* Enter: LR1 = first live range
* LR2 = second live range
* DisallowCASC = true to disallow call arg special coalescing
* into the resulting live range
*
* Return: new live range (LR1 and LR2 now invalid)
*/
LiveRange *GenXLiveness::coalesce(LiveRange *LR1, LiveRange *LR2,
bool DisallowCASC)
{
IGC_ASSERT_MESSAGE(LR1 != LR2, "cannot coalesce an LR to itself");
IGC_ASSERT_MESSAGE(LR1->Category == LR2->Category,
"cannot coalesce two LRs with different categories");
// Make LR1 the one with the longer list of segments.
if (LR2->Segments.size() > LR1->Segments.size()) {
LiveRange *temp = LR1;
LR1 = LR2;
LR2 = temp;
}
LLVM_DEBUG(
dbgs() << "Coalescing \"";
LR1->print(dbgs());
dbgs() << "\" and \"";
LR2->print(dbgs());
dbgs() << "\"\n"
);
// Do the merge of the segments.
merge(LR1, LR2);
// Copy LR2's values across to LR1.
for (auto i = LR2->value_begin(), e = LR2->value_end(); i != e; ++i)
LiveRangeMap[LR1->addValue(*i)] = LR1;
// Use the largest alignment from the two LRs.
LR1->LogAlignment = std::max(LR1->LogAlignment, LR2->LogAlignment);
// If either LR has a non-zero offset, use it.
IGC_ASSERT(!LR1->Offset || !LR2->Offset);
LR1->Offset |= LR2->Offset;
// Set DisallowCASC.
LR1->DisallowCASC |= LR2->DisallowCASC | DisallowCASC;
delete LR2;
LLVM_DEBUG(
dbgs() << " giving \"";
LR1->print(dbgs());
dbgs() << "\"\n"
);
return LR1;
}
/***********************************************************************
* copyInterfere : check whether two live ranges copy-interfere
*
* Two live ranges LR1 and LR2 copy-interfere (a non-commutative relation)
* if LR1 includes a value that is a phi node whose definition is within
* LR2.
*/
bool GenXLiveness::copyInterfere(LiveRange *LR1, LiveRange *LR2) {
if (CoalescingDisabled)
return true;
// Find a phi node value in LR1. It can have at most one, because only
// copy coalescing has occurred up to now, and copy coalescing does not
// occur at a phi node.
for (unsigned i = 0, e = LR1->Values.size(); i != e; ++i) {
auto Phi = dyn_cast<PHINode>(LR1->Values[i].getValue());
if (!Phi)
continue;
// Found a phi node in LR1. A phi node has multiple instruction numbers,
// one for each incoming block. See if any one of those is in LR2's
// live range.
for (unsigned i = 0, e = Phi->getNumIncomingValues(); i != e; ++i)
if (LR2->contains(Numbering->getPhiNumber(Phi, Phi->getIncomingBlock(i))))
return true;
break;
}
return false; // no phi node found
}
/***********************************************************************
* wrapsAround : detects if V1 is a phi node and V2 wraps round to a use
* in a phi node in the same basic block as V1 and after it
*/
bool GenXLiveness::wrapsAround(Value *V1, Value *V2)
{
auto PhiDef = dyn_cast<PHINode>(V1);
if (!PhiDef)
return false;
for (auto ui = V2->use_begin(), ue = V2->use_end(); ui != ue; ++ui) {
if (auto PhiUse = dyn_cast<PHINode>(ui->getUser())) {
if (PhiUse->getParent() == PhiDef->getParent()) {
// Phi use in the same BB. Scan until we find PhiDef or the end
// of the phi nodes.
while (PhiUse != PhiDef) {
PhiUse = dyn_cast<PHINode>(PhiUse->getNextNode());
if (!PhiUse)
return true; // reach end of phi nodes
}
}
}
}
return false;
}
/***********************************************************************
* insertCopy : insert a copy of a non-aggregate value
*
* Enter: InputVal = value to copy
* LR = live range to add the new value to (0 to avoid adjusting
* live ranges)
* InsertBefore = insert copy before this inst
* Name = name to give the new value
* Number = number to give the new instruction(s), 0 for none
*
* Return: The new copy instruction
*
* This inserts multiple copies if the input value is a vector that is
* bigger than two GRFs or a non power of two size.
*
* This method is mostly used from GenXCoalescing, which passes an LR to
* add the new copied value to.
*
* It is also used from GenXLiveRange if it needs to add a copy to break an
* overlapping circular phi value, in which case LR is 0 as we do not want to
* adjust live ranges. Also at this stage there is no baling info to update.
*/
Instruction *GenXLiveness::insertCopy(Value *InputVal, LiveRange *LR,
Instruction *InsertBefore,
const Twine &Name, unsigned Number,
const GenXSubtarget *ST) {
IGC_ASSERT(!isa<Constant>(InputVal));
bool AdjustLRs = LR != nullptr;
LiveRange *SourceLR = nullptr;
if (AdjustLRs)
SourceLR = getLiveRange(InputVal);
auto InputTy = InputVal->getType();
if (InputTy->getScalarType()->isIntegerTy(1)) {
// The input is a predicate.
if (!isa<Constant>(InputVal)) {
// The predicate input is not a constant.
// There is no way in vISA of copying from one
// predicate to another, so we copy all 0s into the destination
// then "or" the source into it.
Instruction *NewInst = CastInst::Create(Instruction::BitCast,
Constant::getNullValue(InputTy), InputTy, Name, InsertBefore);
Numbering->setNumber(NewInst, Number);
if (AdjustLRs)
setLiveRange(SimpleValue(NewInst), LR);
NewInst = BinaryOperator::Create(Instruction::Or, NewInst, InputVal, Name,
InsertBefore);
Numbering->setNumber(NewInst, Number);
if (AdjustLRs)
setLiveRange(SimpleValue(NewInst), LR);
return NewInst;
}
// Predicate input is constant.
auto NewInst = CastInst::Create(Instruction::BitCast, InputVal,
InputTy, Name, InsertBefore);
Numbering->setNumber(NewInst, Number);
if (AdjustLRs)
setLiveRange(SimpleValue(NewInst), LR);
return NewInst;
}
Instruction *NewInst = nullptr;
if (InputTy->isPointerTy()) {
// BitCast used to represent a normal copy.
NewInst = CastInst::Create(Instruction::BitCast, InputVal,
InputVal->getType(), Name, InsertBefore);
if (Number)
Numbering->setNumber(NewInst, Number);
if (AdjustLRs)
setLiveRange(SimpleValue(NewInst), LR);
return NewInst;
}
Region R(InputVal);
IGC_ASSERT(ST);
unsigned MaxNum = getLegalRegionSizeForTarget(
*ST, R, /* StartIdx */ 0, /* Allow2D */ false, R.NumElements);
// Adjust size to Exec size
MaxNum = std::min(MaxNum, TotalEMSize);
if (exactLog2(R.NumElements) >= 0 && R.NumElements <= MaxNum) {
// Can be done with a single copy.
if (SourceLR && (SourceLR->Category != vc::RegCategory::General ||
(LR && LR->Category != vc::RegCategory::General))) {
// Need a category conversion (including the case that the two
// categories are the same but not GENERAL).
NewInst = createConvert(InputVal, Name, InsertBefore);
} else {
// BitCast used to represent a normal copy.
NewInst = CastInst::Create(Instruction::BitCast, InputVal,
InputVal->getType(), Name, InsertBefore);
}
if (Number)
Numbering->setNumber(NewInst, Number);
if (AdjustLRs)
setLiveRange(SimpleValue(NewInst), LR);
return NewInst;
}
auto collectFragment = [](Value *V, unsigned MaxFrag,
SmallVectorImpl<std::pair<unsigned, unsigned>>& Frag,
unsigned MaxElt) {
while (!isa<UndefValue>(V)) {
if (!GenXIntrinsic::isWrRegion(V))
return true;
IntrinsicInst *WII = cast<IntrinsicInst>(V);
Region R = makeRegionFromBaleInfo(WII, BaleInfo());
if (R.Indirect || !R.isContiguous() || !R.isWholeNumRows())
return true;
if ((R.Offset % R.ElementBytes) != 0)
return true;
unsigned Base = R.getOffsetInElements();
for (unsigned Offset = 0; Offset < R.NumElements; /*EMPTY*/) {
unsigned NumElts = std::min(MaxElt, R.NumElements - Offset);
// Round NumElts down to power of 2. That is how many elements we
// are copying this time round the loop.
NumElts = 1 << genx::log2(NumElts);
Frag.push_back(std::make_pair(Base + Offset, NumElts));
Offset += NumElts;
}
V = WII->getOperand(0);
}
if (Frag.size() > MaxFrag)
return true;
std::sort(Frag.begin(), Frag.end());
return false;
};
unsigned NumElements = R.NumElements;
SmallVector<std::pair<unsigned, unsigned>, 8> Fragments;
unsigned MaxCopies = (NumElements + MaxNum - 1) / MaxNum;
if (collectFragment(InputVal, MaxCopies, Fragments, MaxNum)) {
Fragments.clear();
for (unsigned Offset = 0; Offset < NumElements; /*EMPTY*/) {
unsigned NumElts = std::min(MaxNum, NumElements - Offset);
// Round NumElts down to power of 2. That is how many elements we
// are copying this time round the loop.
NumElts = 1 << genx::log2(NumElts);
Fragments.push_back(std::make_pair(Offset, NumElts));
Offset += NumElts;
}
}
// Need to split the copy up. Start with an undef destination.
Value *Res = UndefValue::get(InputVal->getType());
for (auto &I : Fragments) {
unsigned Offset = I.first;
// Set the subregion.
R.NumElements = I.second;
R.Width = R.NumElements;
R.Offset = Offset * R.ElementBytes;
// Create the rdregion. Do not add this to a live range because it is
// going to be baled in to the wrregion.
Instruction *RdRegion = R.createRdRegion(InputVal, Name, InsertBefore,
DebugLoc(), true/*AllowScalar*/);
if (Baling)
Baling->setBaleInfo(RdRegion, BaleInfo(BaleInfo::RDREGION, 0));
if (Number)
Numbering->setNumber(RdRegion, Number);
// Create the wrregion, and mark that it bales in the rdregion (operand 1).
NewInst = R.createWrRegion(Res, RdRegion, Name, InsertBefore, DebugLoc());
if (Number)
Numbering->setNumber(NewInst, Number);
if (Baling) {
BaleInfo BI(BaleInfo::WRREGION);
BI.setOperandBaled(1);
Baling->setBaleInfo(NewInst, BI);
}
if (AdjustLRs) {
// Add the last wrregion to the live range (thus coalescing them all
// together and in with the phi node or two address op that we're doing
// the copy for).
setLiveRange(SimpleValue(NewInst), LR);
}
Res = NewInst;
}
return NewInst;
}
/***********************************************************************
* merge : merge segments of LR2 into LR1
*
* This is equivalent to addSegments followed by sortAndMerge.
*
* Previously there was some code here that attempted to optimize on the
* assumption that the caller passed the one with the longer list of segments
* as LR1. However that became too complicated once we introduced weak and
* strong liveness.
*
* One day we could re-introduce some simple optimized paths, such as when
* LR2 has a single segment.
*/
void GenXLiveness::merge(LiveRange *LR1, LiveRange *LR2)
{
LR1->addSegments(LR2);
LR1->sortAndMerge();
}
/***********************************************************************
* eraseUnusedTree : erase unused tree of instructions
*
* Enter: Inst = root of unused tree
*
* This erases Inst, then recursively erases other instructions that become
* unused. Erased instructions are also removed from liveness.
*
* Other than the given Inst, this does not erase a non-intrinsic call, or
* an intrinsic call with a side effect.
*
* Instead of erasing as we go, we undef operands to make them unused and then
* erase everything at the end. This is required for the case that we have an
* unused DAG of instructions rather than just an unused tree, for example
* where we have a rd-wr sequence and all the rds use the same input.
*/
void GenXLiveness::eraseUnusedTree(Instruction *TopInst)
{
SmallVector<Instruction *, 4> Stack;
std::set<Instruction *> ToErase;
Stack.push_back(TopInst);
while (!Stack.empty()) {
auto Inst = Stack.back();
Stack.pop_back();
if (!Inst->use_empty())
continue;
if (TopInst != Inst) {
if (auto CI = dyn_cast<CallInst>(Inst)) {
if (!GenXIntrinsic::isAnyNonTrivialIntrinsic(CI))
continue;
if (!CI->doesNotAccessMemory())
continue;
}
}
for (unsigned oi = 0, oe = Inst->getNumOperands(); oi != oe; ++oi)
if (auto OpndInst = dyn_cast<Instruction>(Inst->getOperand(oi))) {
Stack.push_back(OpndInst);
Inst->setOperand(oi, UndefValue::get(OpndInst->getType()));
}
removeValue(Inst);
ToErase.insert(Inst);
}
for (auto i = ToErase.begin(), e = ToErase.end(); i != e; ++i)
(*i)->eraseFromParent();
}
/***********************************************************************
* setArgAddressBase : set the base value of an argument indirect address
*
* Enter: Addr = genx.convert.addr instruction
* Base = a base register for the Addr
*/
void GenXLiveness::setArgAddressBase(Value *Addr, Value *Base) {
// There might be several addresses for the one base. So, find and erase an
// old address for the input base.
auto Res = ArgAddressBaseMap.find(Addr);
if (Res != ArgAddressBaseMap.end()) {
Value *PreviousBase = Res->second;
auto AddrsRange = BaseToArgAddrMap.equal_range(PreviousBase);
auto ToRemove = std::find_if(AddrsRange.first, AddrsRange.second,
[Addr](auto It) { return It.second == Addr; });
IGC_ASSERT_MESSAGE(
ToRemove != AddrsRange.second,
"Addr -> PreviousBase exists in ArgAddressBaseMap. It must "
"exist in BaseToArgAddrMap too.");
BaseToArgAddrMap.erase(ToRemove);
}
// Set the new connection between address and base.
ArgAddressBaseMap[Addr] = Base;
BaseToArgAddrMap.insert({Base, Addr});
}
/***********************************************************************
* getAddressBase : get the base register of an address
*
* Enter: Addr = address conversion (genx.convert.addr instruction)
*
* Return: The Value for the base that the address is used with, or some
* other Value that is coalesced with that
*/
Value *GenXLiveness::getAddressBase(Value *Addr)
{
// Get the base register from the rdregion/wrregion that the index is used
// in. This might involve going via an add or an rdregion.
Use *U = &*Addr->use_begin();
auto user = cast<Instruction>(U->getUser());
while (!U->getOperandNo()) {
U = &*user->use_begin();
user = cast<Instruction>(U->getUser());
}
if (GenXIntrinsic::isRdRegion(user))
return user->getOperand(0);
if (GenXIntrinsic::isWrRegion(user)) {
auto Head = Baling->getBaleHead(user);
if (Head && isa<StoreInst>(Head)) {
Value *V = Head->getOperand(1);
V = vc::getUnderlyingGlobalVariable(V);
IGC_ASSERT_MESSAGE(V, "null base not expected");
return V;
}
return user;
}
// The above scheme does not work for an address conversion added by
// GenXArgIndirection. Instead we have AddressBaseMap to provide the mapping.
auto i = ArgAddressBaseMap.find(Addr);
IGC_ASSERT_MESSAGE(i != ArgAddressBaseMap.end(),
"base register not found for address");
Value *BaseV = i->second;
LiveRange *LR = getLiveRange(BaseV);
// Find a SimpleValue in the live range that is not an aggregate member.
for (auto vi = LR->value_begin(), ve = LR->value_end(); vi != ve; ++vi) {
Value *V = vi->getValue();
if (!V->getType()->isAggregateType())
return V;
}
IGC_ASSERT_EXIT_MESSAGE(0, "non-aggregate value not found");
}
/***********************************************************************
* getAddressWithBase : get addresses that base register is a Base
*
* Enter: Base = assumed base
*
* Return: If the input value is a base, return the vector of the corresponding
* arguments indirect addresses, empty vector otherwise.
*/
std::vector<Value *> GenXLiveness::getAddressWithBase(Value *Base) {
auto Res = BaseToArgAddrMap.equal_range(Base);
std::vector<Value *> Bases;
std::transform(Res.first, Res.second, std::back_inserter(Bases),
[](auto It) { return It.second; });
return Bases;
}
/***********************************************************************
* isNoopCastCoalesced : see if the no-op cast has been coalesced away
*
* This handles the case that the input and result of the no-op cast are coalesced
* in to the same live range.
*/
bool GenXLiveness::isNoopCastCoalesced(CastInst *CI)
{
IGC_ASSERT(genx::isNoopCast(CI));
return getLiveRangeOrNull(CI) == getLiveRangeOrNull(CI->getOperand(0));
}
/***********************************************************************
* dump, print : dump the liveness info
*/
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void GenXLiveness::dump()
{
print(errs()); errs() << '\n';
}
void LiveRange::dump() const
{
print(errs()); errs() << '\n';
}
#endif
void GenXLiveness::printValueLiveness(SimpleValue SV, raw_ostream &OS) const {
const LiveRange *LR = getLiveRangeOrNull(SV);
if (!LR)
return;
// Only show an LR if the map iterator is on the value that appears first
// in the LR. That avoids printing the same LR multiple times.
IGC_ASSERT(!LR->value_empty());
auto &&ASV = *(LR->value_begin());
if (SV.getValue() != ASV.getValue() || SV.getIndex() != ASV.getIndex())
return;
LR->print(OS);
OS << "\n";
}
void GenXLiveness::print(raw_ostream &OS, const FunctionGroup *dummy) const {
OS << "GenXLiveness for FunctionGroup " << FG->getName() << "\n";
// Print live ranges for global variables;
for (auto &G : FG->getModule()->globals())
printValueLiveness(&G, OS);
for (auto i = FG->begin(), e = FG->end(); i != e; ++i) {
Function *Func = *i;
// Print live ranges for args.
for (auto fi = Func->arg_begin(), fe = Func->arg_end(); fi != fe; ++fi)
printValueLiveness(&*fi, OS);
// Print live range(s) for unified return value.
if (!Func->getReturnType()->isVoidTy()) {
auto Ret = getUnifiedRetIfExist(Func);
if (Ret)
printValueLiveness(Ret, OS);
}
// Print live ranges for code.
for (auto &Inst : instructions(Func)) {
auto *InstStructType = dyn_cast<StructType>(Inst.getType());
if (!InstStructType) {
printValueLiveness(&Inst, OS);
continue;
}
for (unsigned i = 0, e = IndexFlattener::getNumElements(InstStructType);
i != e; ++i) {
auto SV = SimpleValue(&Inst, i);
printValueLiveness(SV, OS);
}
}
}
OS << "\n";
}
/***********************************************************************
* LiveRange::testLiveRanges : tests if no segments abut or overlap or are
* in the wrong order. Live range's segments should be well formed.
*/
bool LiveRange::testLiveRanges() const
{
auto testAdjacentSegments = [](const Segment& A, const Segment& B)
{
const bool P1 = (A.Strength != B.Strength);
const bool P2 = (A.getEnd() < B.getStart());
const bool SegmentIsGood = (P1 || P2);
IGC_ASSERT(SegmentIsGood);
const bool StopSearch = !SegmentIsGood;
return StopSearch;
};
const_iterator Begin = begin();
const_iterator End = end();
const_iterator Failed = std::adjacent_find(Begin, End, testAdjacentSegments);
const bool Result = (Failed == End);
return Result;
}
/***********************************************************************
* LiveRange::addSegment : add a segment to a live range
*
* The segment might already be covered by an existing segment, in which
* case nothing changes.
*
* It would be inefficient to implement coalesce() in terms of this, because
* it might have to shuffle lots of elements along by one each time.
* This function only gets called when adding a single segment to a live
* range when inserting a copy in coalescing.
*/
void LiveRange::addSegment(Segment Seg)
{
iterator i = find(Seg.getStart()), e = end();
if (i == e) {
// New segment off end.
Segments.push_back(Seg);
} else if (i->getStart() <= Seg.getStart()) {
// New segment is covered by or overlaps the end of old segment i.
if (i->getEnd() < Seg.getEnd()) {
i->setEnd(Seg.getEnd());
// See if it covers or overlaps any later segments.
iterator j = i + 1;
while (j != e) {
if (j->getStart() > Seg.getEnd())
break;
i->setEnd(j->getEnd());
if (j->getEnd() >= Seg.getEnd())
break;
++j;
}
Segments.erase(i + 1, j);
}
} else if (i->getStart() == Seg.getEnd()) {
// New segment abuts start of old segment i, without abutting or
// overlapping anything before.
i->setStart(Seg.getStart());
} else {
// New segment is completely in a hole just before i.
Segments.insert(i, Seg);
}
IGC_ASSERT(testLiveRanges());
}
/***********************************************************************
* LiveRange::setSegmentsFrom : for this live range, clear out its segments
* and copy them from the other live range
*/
void LiveRange::setSegmentsFrom(LiveRange *Other)
{
Segments.clear();
Segments.append(Other->Segments.begin(), Other->Segments.end());
}
/***********************************************************************
* LiveRange::addSegments : add segments of LR2 into this
*/
void LiveRange::addSegments(LiveRange *LR2)
{
Segments.append(LR2->Segments.begin(), LR2->Segments.end());
}
/***********************************************************************
* LiveRange::sortAndMerge : after doing some push_backs, sort the segments,
* and merge overlapping/adjacent ones
*/
void LiveRange::sortAndMerge() {
std::sort(Segments.begin(), Segments.end());
// Ensure that there are no duplicate segments:
Segments_t::iterator ip;
ip = std::unique(Segments.begin(), Segments.end());
Segments.resize(std::distance(Segments.begin(), ip));
Segments_t SegmentsSortedEnd = Segments;
std::sort(SegmentsSortedEnd.begin(), SegmentsSortedEnd.end(),
[](Segment L, Segment R) {
if (L.getEnd() != R.getEnd())
return L.getEnd() < R.getEnd();
return L.getStart() < R.getStart();
});
Segments_t NewSegments;
std::unordered_set<Segment> OpenedSegments;
Segment *SS = Segments.begin();
Segment *ES = SegmentsSortedEnd.begin();
unsigned prevBorder = 0;
unsigned curBorder = 0;
bool isStartBorder;
// Split & Merge
while (ES != SegmentsSortedEnd.end()) {
if (SS != Segments.end() && SS->getStart() < ES->getEnd()) {
isStartBorder = true;
curBorder = SS->getStart();
} else {
isStartBorder = false;
curBorder = ES->getEnd();
}
// To create or extend segment, first check that there are
// open segments or that we haven't already created or extended one
if (OpenedSegments.size() > 0 && prevBorder < curBorder) {
Segment NS =
*std::max_element(OpenedSegments.begin(), OpenedSegments.end(),
[](Segment L, Segment R) {
return L.Strength < R.Strength;
}); // New segment
if (NewSegments.size() > 0 &&
NewSegments.rbegin()->getEnd() == prevBorder &&
// This segment and previous segment abut or overlap. Merge
// as long as they have the same strength.
(NS.Strength == NewSegments.rbegin()->Strength ||
// Also allow for the case that the first one is strong and the
// second one is phicpy. The resulting merged segment is strong,
// because a phicpy segment is valid only if it starts in the
// same place as when it was originally created and there is no
// liveness just before it.
(NS.Strength == Segment::PHICPY &&
NewSegments.rbegin()->Strength == Segment::STRONG))) {
// In these cases we can extend
NewSegments.rbegin()->setEnd(curBorder);
} else {
NS.setStart(prevBorder);
NS.setEnd(curBorder);
NewSegments.push_back(NS);
}
}
prevBorder = curBorder;
if (isStartBorder)
OpenedSegments.insert(*SS++);
else
OpenedSegments.erase(*ES++);
}
Segments = NewSegments;
}
/***********************************************************************
* LiveRange::getLength : add up the number of instructions covered by this LR
*/
unsigned LiveRange::getLength(bool WithWeak) const {
unsigned Length = 0;
for (auto i = begin(), e = end(); i != e; ++i) {
if (i->isWeak() && !WithWeak)
continue;
Length += i->getEnd() - i->getStart();
}
return Length;
}
/***********************************************************************
* LiveRange::print : print the live range
* Simplevalues of LR : segments { details }
* Detailed mode exists to print LLVM values
*/
void LiveRange::print(raw_ostream &OS, bool Details) const {
if (Details)
OS << "LR values:\n";
if (Values.empty()) {
OS << "<Empty LR>";
return;
}
for (auto &&V : Values) {
if (!Details)
OS << V << "; ";
else
OS << *V.getValue() << "\n";
}
if (!Details)
OS << ":";
else
OS << "LR Segments and details: ";
if (Segments.empty())
OS << "<Empty Segments>";
else
printSegments(OS);
StringRef Cat = vc::getRegCategoryName(Category);
OS << "{" << Cat << ",align" << (1U << LogAlignment);
if (Offset)
OS << ",offset" << Offset;
OS << "}";
}
/***********************************************************************
* LiveRange::printSegments : print the live range's segments
*/
void LiveRange::printSegments(raw_ostream &OS) const
{
for (auto ri = Segments.begin(), re = Segments.end();
ri != re; ++ri) {
OS << "[";
switch (ri->Strength) {
case Segment::WEAK: OS << "w"; break;
case Segment::PHICPY: OS << "ph"; break;
case Segment::STRONG: /* do nothing */ break;
}
OS << ri->getStart() << "," << ri->getEnd() << ")";
}
}
/***********************************************************************
* CallGraph::build : build the call graph for the FunctionGroup
*
* The call graph is acyclic because no recursive edges added here
* CM supports recursion though
*/
void genx::CallGraph::build(GenXLiveness *Liveness) {
Nodes.clear();
// Create a node for each Function.
for (auto fgi = FG->begin(), fge = FG->end(); fgi != fge; ++fgi) {
Function *F = *fgi;
(void)Nodes[F];
}
// For each Function, find its call sites and add edges for them.
for (auto fgi = FG->begin() + 1, fge = FG->end(); fgi != fge; ++fgi) {
Function *F = *fgi;
for (Value::use_iterator ui = F->use_begin(), ue = F->use_end(); ui != ue;
++ui) {
// TODO: deduce possible callsites thru cast chains
if (isa<CallInst>(ui->getUser())) {
auto Call = cast<CallInst>(ui->getUser());
auto Caller = Call->getParent()->getParent();
// do not add edges for indirect, recursive and intrinsic calls
if (Call->getCalledFunction() &&
!GenXIntrinsic::isAnyNonTrivialIntrinsic(Call->getCalledFunction()) &&
Caller != F)
Nodes[Caller].insert(
Edge(Liveness->getNumbering()->getNumber(Call), Call));
}
}
}
}
INITIALIZE_PASS_BEGIN(GenXLivenessWrapper, "GenXLivenessWrapper",
"GenXLivenessWrapper", false, false)
INITIALIZE_PASS_END(GenXLivenessWrapper, "GenXLivenessWrapper",
"GenXLivenessWrapper", false, false)
ModulePass *llvm::createGenXLivenessWrapperPass() {
initializeGenXLivenessWrapperPass(*PassRegistry::getPassRegistry());
return new GenXLivenessWrapper();
}
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