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Factor out the code for recomputing an LSRUse's Regs set after some

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of its formulae have been removed into a helper function, and also
teach it how to update the RegUseTracker.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104087 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-05-18 23:42:37 +00:00
parent 417d1705bb
commit b2df433f71
1 changed files with 40 additions and 17 deletions
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57
lib/Transforms/Scalar/LoopStrengthReduce.cpp
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@ -112,6 +112,7 @@ class RegUseTracker {
public:
void CountRegister(const SCEV *Reg, size_t LUIdx);
void DropRegister(const SCEV *Reg, size_t LUIdx);
bool isRegUsedByUsesOtherThan(const SCEV *Reg, size_t LUIdx) const;
@ -140,6 +141,15 @@ RegUseTracker::CountRegister(const SCEV *Reg, size_t LUIdx) {
RSD.UsedByIndices.set(LUIdx);
}
void
RegUseTracker::DropRegister(const SCEV *Reg, size_t LUIdx) {
RegUsesTy::iterator It = RegUsesMap.find(Reg);
assert(It != RegUsesMap.end());
RegSortData &RSD = It->second;
assert(RSD.UsedByIndices.size() > LUIdx);
RSD.UsedByIndices.reset(LUIdx);
}
bool
RegUseTracker::isRegUsedByUsesOtherThan(const SCEV *Reg, size_t LUIdx) const {
if (!RegUsesMap.count(Reg)) return false;
@ -943,6 +953,7 @@ public:
bool InsertFormula(const Formula &F);
void DeleteFormula(Formula &F);
void RecomputeRegs(size_t LUIdx, RegUseTracker &Reguses);
void check() const;
@ -986,6 +997,24 @@ void LSRUse::DeleteFormula(Formula &F) {
Formulae.pop_back();
}
/// RecomputeRegs - Recompute the Regs field, and update RegUses.
void LSRUse::RecomputeRegs(size_t LUIdx, RegUseTracker &RegUses) {
// Now that we've filtered out some formulae, recompute the Regs set.
SmallPtrSet<const SCEV *, 4> OldRegs = Regs;
Regs.clear();
for (size_t FIdx = 0, NumForms = Formulae.size(); FIdx != NumForms; ++FIdx) {
Formula &F = Formulae[FIdx];
if (F.ScaledReg) Regs.insert(F.ScaledReg);
Regs.insert(F.BaseRegs.begin(), F.BaseRegs.end());
}
// Update the RegTracker.
for (SmallPtrSet<const SCEV *, 4>::iterator I = OldRegs.begin(),
E = OldRegs.end(); I != E; ++I)
if (!Regs.count(*I))
RegUses.DropRegister(*I, LUIdx);
}
void LSRUse::print(raw_ostream &OS) const {
OS << "LSR Use: Kind=";
switch (Kind) {
@ -2609,6 +2638,7 @@ void LSRInstance::FilterOutUndesirableDedicatedRegisters() {
FormulaSorter Sorter(L, LU, SE, DT);
DEBUG(dbgs() << "Filtering for use "; LU.print(dbgs()); dbgs() << "\n");
bool Any = false;
for (size_t FIdx = 0, NumForms = LU.Formulae.size();
FIdx != NumForms; ++FIdx) {
Formula &F = LU.Formulae[FIdx];
@ -2643,18 +2673,13 @@ void LSRInstance::FilterOutUndesirableDedicatedRegisters() {
LU.DeleteFormula(F);
--FIdx;
--NumForms;
Any = true;
continue;
}
}
// Now that we've filtered out some formulae, recompute the Regs set.
LU.Regs.clear();
for (size_t FIdx = 0, NumForms = LU.Formulae.size();
FIdx != NumForms; ++FIdx) {
Formula &F = LU.Formulae[FIdx];
if (F.ScaledReg) LU.Regs.insert(F.ScaledReg);
LU.Regs.insert(F.BaseRegs.begin(), F.BaseRegs.end());
}
if (Any)
LU.RecomputeRegs(LUIdx, RegUses);
// Reset this to prepare for the next use.
BestFormulae.clear();
@ -2727,14 +2752,11 @@ void LSRInstance::NarrowSearchSpaceUsingHeuristics() {
// In any use with formulae which references this register, delete formulae
// which don't reference it.
for (SmallVectorImpl<LSRUse>::iterator I = Uses.begin(),
E = Uses.end(); I != E; ++I) {
LSRUse &LU = *I;
for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) {
LSRUse &LU = Uses[LUIdx];
if (!LU.Regs.count(Best)) continue;
// Clear out the set of used regs; it will be recomputed.
LU.Regs.clear();
bool Any = false;
for (size_t i = 0, e = LU.Formulae.size(); i != e; ++i) {
Formula &F = LU.Formulae[i];
if (!F.referencesReg(Best)) {
@ -2742,13 +2764,14 @@ void LSRInstance::NarrowSearchSpaceUsingHeuristics() {
LU.DeleteFormula(F);
--e;
--i;
Any = true;
assert(e != 0 && "Use has no formulae left! Is Regs inconsistent?");
continue;
}
if (F.ScaledReg) LU.Regs.insert(F.ScaledReg);
LU.Regs.insert(F.BaseRegs.begin(), F.BaseRegs.end());
}
if (Any)
LU.RecomputeRegs(LUIdx, RegUses);
}
DEBUG(dbgs() << "After pre-selection:\n";