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/*========================== begin_copyright_notice ============================
Copyright (C) 2017-2021 Intel Corporation
SPDX-License-Identifier: MIT
============================= end_copyright_notice ===========================*/
#include "GenXPressureTracker.h"
#include "FunctionGroup.h"
#include "GenX.h"
#include "GenXBaling.h"
#include "GenXLiveness.h"
#include "GenXUtil.h"
#include "vc/Utils/GenX/RegCategory.h"
#include "vc/Utils/General/Types.h"
#include "Probe/Assertion.h"
using namespace llvm;
using namespace genx;
namespace {
struct LiveRangeAndLength {
LiveRange *LR;
unsigned Length;
LiveRangeAndLength(LiveRange *LR, unsigned Length) : LR(LR), Length(Length) {}
bool operator<(const LiveRangeAndLength &Rhs) const {
return Length > Rhs.Length;
}
};
} // namespace
unsigned PressureTracker::getSizeInBytes(LiveRange *LR, bool AllowWidening) {
SimpleValue SV = *LR->value_begin();
Value *V = SV.getValue();
Type *Ty = IndexFlattener::getElementType(V->getType(), SV.getIndex());
unsigned Bytes = vc::getTypeSize(Ty, &DL).inWordsCeil() * WordBytes;
if (!AllowWidening)
return Bytes;
// Check if this will be a live range to be promoted to a word vector:
// - this is a byte vector
// - non-of values will be used in indirect regions
// - all uses are in the same block (local variables only)
//
auto toWiden = [=]() -> bool {
if (!Ty->isVectorTy() ||
!cast<VectorType>(Ty)->getElementType()->isIntegerTy(8))
return false;
BasicBlock *DefBB = nullptr;
for (auto I = LR->value_begin(), E = LR->value_end(); I != E; ++I) {
auto Inst = dyn_cast<Instruction>((*I).getValue());
if (!Inst)
return false;
if (!DefBB)
DefBB = Inst->getParent();
if (DefBB != Inst->getParent() || Inst->isUsedOutsideOfBlock(DefBB))
return false;
for (auto UI : Inst->users()) {
if (GenXIntrinsic::isRdRegion(UI) || GenXIntrinsic::isWrRegion(UI)) {
Region R = makeRegionFromBaleInfo(cast<Instruction>(UI), BaleInfo());
if (R.Indirect)
return false;
}
}
}
// OK, this is a candidate for widening.
return true;
};
if (toWiden()) {
WidenCandidates.push_back(LR);
Bytes *= 2;
}
return Bytes;
}
// Decrease pressure assuming no widening on variable for LR.
void PressureTracker::decreasePressure(LiveRange *LR) {
if (!LR || LR->getCategory() != vc::RegCategory::General)
return;
#if _DEBUG
auto I = std::find(WidenCandidates.begin(), WidenCandidates.end(), LR);
IGC_ASSERT(I != WidenCandidates.end());
#endif
unsigned Bytes = getSizeInBytes(LR, /*AllowWidening*/ false);
for (auto SI = LR->begin(), SE = LR->end(); SI != SE; ++SI) {
for (unsigned i = SI->getStart(); i != SI->getEnd(); ++i) {
IGC_ASSERT(i < Pressure.size());
IGC_ASSERT(Pressure[i] >= Bytes);
Pressure[i] -= Bytes;
}
}
calculateRedSegments();
}
void PressureTracker::calculate() {
std::vector<LiveRange *> LRs;
getLiveRanges(LRs);
std::vector<LiveRangeAndLength> LRLs;
for (auto LR : LRs)
LRLs.emplace_back(LR, LR->getLength(/*WithWeak*/ false));
LRs.clear();
std::sort(LRLs.begin(), LRLs.end());
// Keep count of the rp at each instruction number.
Pressure.clear();
for (auto &I : LRLs) {
LiveRange *LR = I.LR;
unsigned Bytes = getSizeInBytes(LR, WithByteWidening);
for (auto SI = LR->begin(), SE = LR->end(); SI != SE; ++SI) {
if (SI->getEnd() >= Pressure.size())
Pressure.resize(SI->getEnd() + 1, 0);
for (unsigned i = SI->getStart(); i != SI->getEnd(); ++i)
Pressure[i] += Bytes;
}
}
}
// Calculate high pressure segments.
void PressureTracker::calculateRedSegments() {
HighPressureSegments.clear();
unsigned UNDEF = std::numeric_limits<unsigned>::max();
unsigned B = UNDEF;
unsigned E = UNDEF;
for (unsigned i = 0; i < Pressure.size(); ++i) {
if (Pressure[i] >= THRESHOLD) {
if (B == UNDEF)
B = i;
else
E = i;
} else {
if (B != UNDEF && E != UNDEF)
HighPressureSegments.emplace_back(B, E);
else if (B != UNDEF)
HighPressureSegments.emplace_back(B, B);
B = E = UNDEF;
}
}
}
// Check if segment [B, E] intersects with a high pressure region or not.
bool PressureTracker::intersectWithRedRegion(unsigned B, unsigned E) const {
for (auto S : HighPressureSegments) {
unsigned B1 = S.Begin;
unsigned E1 = S.End;
if (B > E1)
continue;
return E >= B1;
}
return false;
}
bool PressureTracker::intersectWithRedRegion(LiveRange *LR) const {
if (!LR || LR->getCategory() == vc::RegCategory::None)
return false;
for (auto I = LR->begin(), E = LR->end(); I != E; ++I)
if (intersectWithRedRegion(I->getStart(), I->getEnd()))
return true;
return false;
}
void PressureTracker::getLiveRanges(std::vector<LiveRange *> &LRs) {
for (auto I = FG.begin(), E = FG.end(); I != E; ++I) {
Function *F = *I;
for (auto &Arg : F->args())
getLiveRangesForValue(&Arg, LRs);
if (I != FG.begin() && !F->getReturnType()->isVoidTy())
getLiveRangesForValue(Liveness->getUnifiedRet(F), LRs);
for (auto &BB : F->getBasicBlockList())
for (auto &Inst : BB.getInstList())
getLiveRangesForValue(&Inst, LRs);
}
}
void PressureTracker::getLiveRangesForValue(
Value *V, std::vector<LiveRange *> &LRs) const {
auto Ty = V->getType();
for (unsigned i = 0, e = IndexFlattener::getNumElements(Ty); i != e; ++i) {
SimpleValue SV(V, i);
LiveRange *LR = Liveness->getLiveRangeOrNull(SV);
if (!LR || LR->getCategory() == vc::RegCategory::None)
continue;
// Only process an LR if the map iterator is on the value that appears
// first in the LR. That avoids processing the same LR multiple times.
if (SV != *LR->value_begin())
continue;
LRs.push_back(LR);
}
}
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