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R600: fix PHI value adding in the structurizer

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Otherwise we sometimes produce invalid code.

Patch by: Christian König

Signed-off-by: Christian König <christian.koenig@amd.com>
Tested-by: Michel Dänzer <michel.daenzer@amd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174760 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Tom Stellard 2013-02-08 22:24:35 +00:00
parent d3da6d5dda
commit 13cf6cb57a
1 changed files with 81 additions and 65 deletions
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146
lib/Target/R600/AMDGPUStructurizeCFG.cpp
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@ -41,6 +41,7 @@ typedef DenseMap<BasicBlock *, PhiMap> BBPhiMap;
typedef DenseMap<BasicBlock *, Value *> BBPredicates;
typedef DenseMap<BasicBlock *, BBPredicates> PredMap;
typedef DenseMap<BasicBlock *, unsigned> VisitedMap;
typedef DenseMap<BasicBlock *, BBVector> BB2BBVecMap;
// The name for newly created blocks.
@ -109,6 +110,7 @@ class AMDGPUStructurizeCFG : public RegionPass {
VisitedMap Visited;
PredMap Predicates;
BBPhiMap DeletedPhis;
BB2BBVecMap AddedPhis;
BBVector FlowsInserted;
BasicBlock *LoopStart;
@ -126,16 +128,18 @@ class AMDGPUStructurizeCFG : public RegionPass {
void collectInfos();
void delPhiValues(BasicBlock *From, BasicBlock *To);
void addPhiValues(BasicBlock *From, BasicBlock *To);
void setPhiValues();
bool dominatesPredicates(BasicBlock *A, BasicBlock *B);
void killTerminator(BasicBlock *BB);
RegionNode *skipChained(RegionNode *Node);
void delPhiValues(BasicBlock *From, BasicBlock *To);
void addPhiValues(BasicBlock *From, BasicBlock *To);
BasicBlock *getNextFlow(BasicBlock *Prev);
bool isPredictableTrue(BasicBlock *Prev, BasicBlock *Node);
@ -309,6 +313,76 @@ void AMDGPUStructurizeCFG::collectInfos() {
}
}
/// \brief Remove all PHI values coming from "From" into "To" and remember
/// them in DeletedPhis
void AMDGPUStructurizeCFG::delPhiValues(BasicBlock *From, BasicBlock *To) {
PhiMap &Map = DeletedPhis[To];
for (BasicBlock::iterator I = To->begin(), E = To->end();
I != E && isa<PHINode>(*I);) {
PHINode &Phi = cast<PHINode>(*I++);
while (Phi.getBasicBlockIndex(From) != -1) {
Value *Deleted = Phi.removeIncomingValue(From, false);
Map[&Phi].push_back(std::make_pair(From, Deleted));
}
}
}
/// \brief Add a dummy PHI value as soon as we knew the new predecessor
void AMDGPUStructurizeCFG::addPhiValues(BasicBlock *From, BasicBlock *To) {
for (BasicBlock::iterator I = To->begin(), E = To->end();
I != E && isa<PHINode>(*I);) {
PHINode &Phi = cast<PHINode>(*I++);
Value *Undef = UndefValue::get(Phi.getType());
Phi.addIncoming(Undef, From);
}
AddedPhis[To].push_back(From);
}
/// \brief Add the real PHI value as soon as everything is set up
void AMDGPUStructurizeCFG::setPhiValues() {
SSAUpdater Updater;
for (BB2BBVecMap::iterator AI = AddedPhis.begin(), AE = AddedPhis.end();
AI != AE; ++AI) {
BasicBlock *To = AI->first;
BBVector &From = AI->second;
if (!DeletedPhis.count(To))
continue;
PhiMap &Map = DeletedPhis[To];
for (PhiMap::iterator PI = Map.begin(), PE = Map.end();
PI != PE; ++PI) {
PHINode *Phi = PI->first;
Value *Undef = UndefValue::get(Phi->getType());
Updater.Initialize(Phi->getType(), "");
Updater.AddAvailableValue(&Func->getEntryBlock(), Undef);
Updater.AddAvailableValue(To, Undef);
for (BBValueVector::iterator VI = PI->second.begin(),
VE = PI->second.end(); VI != VE; ++VI) {
Updater.AddAvailableValue(VI->first, VI->second);
}
for (BBVector::iterator FI = From.begin(), FE = From.end();
FI != FE; ++FI) {
int Idx = Phi->getBasicBlockIndex(*FI);
assert(Idx != -1);
Phi->setIncomingValue(Idx, Updater.GetValueAtEndOfBlock(*FI));
}
}
DeletedPhis.erase(To);
}
assert(DeletedPhis.empty());
}
/// \brief Does A dominate all the predicates of B ?
bool AMDGPUStructurizeCFG::dominatesPredicates(BasicBlock *A, BasicBlock *B) {
BBPredicates &Preds = Predicates[B];
@ -406,57 +480,6 @@ RegionNode *AMDGPUStructurizeCFG::skipChained(RegionNode *Node) {
return ParentRegion->getNode(wireFlowBlock(BB, Next));
}
/// \brief Remove all PHI values coming from "From" into "To" and remember
/// them in DeletedPhis
void AMDGPUStructurizeCFG::delPhiValues(BasicBlock *From, BasicBlock *To) {
PhiMap &Map = DeletedPhis[To];
for (BasicBlock::iterator I = To->begin(), E = To->end();
I != E && isa<PHINode>(*I);) {
PHINode &Phi = cast<PHINode>(*I++);
while (Phi.getBasicBlockIndex(From) != -1) {
Value *Deleted = Phi.removeIncomingValue(From, false);
Map[&Phi].push_back(std::make_pair(From, Deleted));
}
}
}
/// \brief Add the PHI values back once we knew the new predecessor
void AMDGPUStructurizeCFG::addPhiValues(BasicBlock *From, BasicBlock *To) {
if (!DeletedPhis.count(To))
return;
PhiMap &Map = DeletedPhis[To];
SSAUpdater Updater;
for (PhiMap::iterator I = Map.begin(), E = Map.end(); I != E; ++I) {
PHINode *Phi = I->first;
Updater.Initialize(Phi->getType(), "");
BasicBlock *Fallback = To;
bool HaveFallback = false;
for (BBValueVector::iterator VI = I->second.begin(), VE = I->second.end();
VI != VE; ++VI) {
Updater.AddAvailableValue(VI->first, VI->second);
BasicBlock *Dom = DT->findNearestCommonDominator(Fallback, VI->first);
if (Dom == VI->first)
HaveFallback = true;
else if (Dom != Fallback)
HaveFallback = false;
Fallback = Dom;
}
if (!HaveFallback) {
Value *Undef = UndefValue::get(Phi->getType());
Updater.AddAvailableValue(Fallback, Undef);
}
Phi->addIncoming(Updater.GetValueAtEndOfBlock(From), From);
}
DeletedPhis.erase(To);
}
/// \brief Create a new flow node and update dominator tree and region info
BasicBlock *AMDGPUStructurizeCFG::getNextFlow(BasicBlock *Prev) {
LLVMContext &Context = Func->getContext();
@ -554,6 +577,7 @@ BasicBlock *AMDGPUStructurizeCFG::wireFlowBlock(BasicBlock *Prev,
/// branches only have undefined conditions.
void AMDGPUStructurizeCFG::createFlow() {
DeletedPhis.clear();
AddedPhis.clear();
BasicBlock *Prev = Order.pop_back_val()->getEntry();
assert(Prev == ParentRegion->getEntry() && "Incorrect node order!");
@ -601,18 +625,8 @@ void AMDGPUStructurizeCFG::createFlow() {
if (DT->dominates(ParentRegion->getEntry(), Exit))
DT->changeImmediateDominator(Exit, Prev);
if (LoopStart && LoopEnd) {
BBVector::iterator FI = std::find(FlowsInserted.begin(),
FlowsInserted.end(),
LoopStart);
for (; *FI != LoopEnd; ++FI) {
addPhiValues(*FI, (*FI)->getTerminator()->getSuccessor(0));
}
}
assert(Order.empty());
assert(Visited.empty());
assert(DeletedPhis.empty());
}
/// \brief Insert the missing branch conditions
@ -697,12 +711,14 @@ bool AMDGPUStructurizeCFG::runOnRegion(Region *R, RGPassManager &RGM) {
collectInfos();
createFlow();
insertConditions();
setPhiValues();
rebuildSSA();
Order.clear();
Visited.clear();
Predicates.clear();
DeletedPhis.clear();
AddedPhis.clear();
FlowsInserted.clear();
return true;