RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-24 03:33:20 +01:00
Code Issues Projects Releases Wiki Activity

Update dominator info for the middle blocks created while spliting

Browse Source 
exit edge to preserve LCSSA.

Fix dominance frontier update during loop unswitch. This fixes PR 1589, again

llvm-svn: 40737
This commit is contained in:
Devang Patel 2007-08-02 15:25:57 +00:00
parent a599a813d5
commit 937b07fb5e
3 changed files with 140 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

92
lib/Transforms/Scalar/LoopUnswitch.cpp
View File

@ -543,17 +543,8 @@ void LoopUnswitch::EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val,
std::swap(TrueDest, FalseDest);
// Insert the new branch.
BranchInst *BRI = new BranchInst(TrueDest, FalseDest, BranchVal, InsertPt);
new BranchInst(TrueDest, FalseDest, BranchVal, InsertPt);
// Update dominator info.
// BranchVal is a new preheader so it dominates true and false destination
// loop headers.
if (DominatorTree *DT = getAnalysisToUpdate<DominatorTree>()) {
DT->changeImmediateDominator(TrueDest, BRI->getParent());
DT->changeImmediateDominator(FalseDest, BRI->getParent());
}
// No need to update DominanceFrontier. BRI->getParent() dominated TrueDest
// and FalseDest anyway. Now it immediately dominates them.
}
@ -635,12 +626,14 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
// Split all of the edges from inside the loop to their exit blocks. Update
// the appropriate Phi nodes as we do so.
SmallVector<BasicBlock *,8> MiddleBlocks;
for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) {
BasicBlock *ExitBlock = ExitBlocks[i];
std::vector<BasicBlock*> Preds(pred_begin(ExitBlock), pred_end(ExitBlock));
for (unsigned j = 0, e = Preds.size(); j != e; ++j) {
BasicBlock* MiddleBlock = SplitEdge(Preds[j], ExitBlock, this);
MiddleBlocks.push_back(MiddleBlock);
BasicBlock* StartBlock = Preds[j];
BasicBlock* EndBlock;
if (MiddleBlock->getSinglePredecessor() == ExitBlock) {
@ -685,6 +678,9 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
// Add exit blocks to the loop blocks.
LoopBlocks.insert(LoopBlocks.end(), ExitBlocks.begin(), ExitBlocks.end());
DominanceFrontier *DF = getAnalysisToUpdate<DominanceFrontier>();
DominatorTree *DT = getAnalysisToUpdate<DominatorTree>();
// Next step, clone all of the basic blocks that make up the loop (including
// the loop preheader and exit blocks), keeping track of the mapping between
// the instructions and blocks.
@ -698,14 +694,19 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
LPM->cloneBasicBlockSimpleAnalysis(LoopBlocks[i], New, L);
}
// Update dominator info
DominanceFrontier *DF = getAnalysisToUpdate<DominanceFrontier>();
if (DominatorTree *DT = getAnalysisToUpdate<DominatorTree>())
for (unsigned i = 0, e = LoopBlocks.size(); i != e; ++i) {
BasicBlock *LBB = LoopBlocks[i];
BasicBlock *NBB = NewBlocks[i];
CloneDomInfo(NBB, LBB, NewPreheader, OrigPreheader,
OrigHeader, DT, DF, ValueMap);
// OutSiders are basic block that are dominated by original header and
// at the same time they are not part of loop.
SmallPtrSet<BasicBlock *, 8> OutSiders;
if (DT) {
DomTreeNode *OrigHeaderNode = DT->getNode(OrigHeader);
for(std::vector<DomTreeNode*>::iterator DI = OrigHeaderNode->begin(),
DE = OrigHeaderNode->end(); DI != DE; ++DI) {
BasicBlock *B = (*DI)->getBlock();
DenseMap<const Value*, Value*>::iterator VI = ValueMap.find(B);
if (VI == ValueMap.end())
OutSiders.insert(B);
}
}
// Splice the newly inserted blocks into the function right before the
@ -760,6 +761,61 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
OldBR->eraseFromParent();
LPM->deleteSimpleAnalysisValue(OldBR, L);
// Update dominator info
if (DF && DT) {
// Clone dominator info for all cloned basic block.
for (unsigned i = 0, e = LoopBlocks.size(); i != e; ++i) {
BasicBlock *LBB = LoopBlocks[i];
BasicBlock *NBB = NewBlocks[i];
CloneDomInfo(NBB, LBB, NewPreheader, OrigPreheader,
OrigHeader, DT, DF, ValueMap);
// Remove any OutSiders from LBB and NBB's dominance frontier.
DominanceFrontier::iterator LBBI = DF->find(LBB);
if (LBBI != DF->end()) {
DominanceFrontier::DomSetType &LBSet = LBBI->second;
for (DominanceFrontier::DomSetType::iterator LI = LBSet.begin(),
LE = LBSet.end(); LI != LE; ++LI) {
BasicBlock *B = *LI;
if (OutSiders.count(B))
DF->removeFromFrontier(LBBI, B);
}
}
// Remove any OutSiders from LBB and NBB's dominance frontier.
DominanceFrontier::iterator NBBI = DF->find(NBB);
if (NBBI != DF->end()) {
DominanceFrontier::DomSetType NBSet = NBBI->second;
for (DominanceFrontier::DomSetType::iterator NI = NBSet.begin(),
NE = NBSet.end(); NI != NE; ++NI) {
BasicBlock *B = *NI;
if (OutSiders.count(B))
DF->removeFromFrontier(NBBI, B);
}
}
}
// MiddleBlocks are dominated by original pre header. SplitEdge updated
// MiddleBlocks' dominance frontier appropriately.
for (unsigned i = 0, e = MiddleBlocks.size(); i != e; ++i) {
BasicBlock *MBB = MiddleBlocks[i];
if (!MBB->getSinglePredecessor())
DT->changeImmediateDominator(MBB, OrigPreheader);
}
// All Outsiders are now dominated by original pre header.
for (SmallPtrSet<BasicBlock *, 8>::iterator OI = OutSiders.begin(),
OE = OutSiders.end(); OI != OE; ++OI) {
BasicBlock *OB = *OI;
DT->changeImmediateDominator(OB, OrigPreheader);
}
// New loop headers are dominated by original preheader
DT->changeImmediateDominator(NewBlocks[0], OrigPreheader);
DT->changeImmediateDominator(LoopBlocks[0], OrigPreheader);
}
LoopProcessWorklist.push_back(NewLoop);
redoLoop = true;

10
lib/VMCore/Dominators.cpp
View File

@ -627,6 +627,15 @@ void DominanceFrontier::splitBlock(BasicBlock *NewBB) {
if (!DT.dominates(NewBB, NewBBSucc))
NewBBDominatesNewBBSucc = false;
// NewBBSucc inherites original NewBB frontier.
DominanceFrontier::iterator NewBBI = find(NewBB);
if (NewBBI != end()) {
DominanceFrontier::DomSetType NewBBSet = NewBBI->second;
DominanceFrontier::DomSetType NewBBSuccSet;
NewBBSuccSet.insert(NewBBSet.begin(), NewBBSet.end());
addBasicBlock(NewBBSucc, NewBBSuccSet);
}
// If NewBB dominates NewBBSucc, then DF(NewBB) is now going to be the
// DF(PredBlocks[0]) without the stuff that the new block does not dominate
// a predecessor of.
@ -648,7 +657,6 @@ void DominanceFrontier::splitBlock(BasicBlock *NewBB) {
++SetI;
}
DominanceFrontier::iterator NewBBI = find(NewBB);
if (NewBBI != end()) {
DominanceFrontier::DomSetType NewBBSet = NewBBI->second;
NewBBSet.insert(Set.begin(), Set.end());

55
test/Transforms/LoopUnswitch/2007-08-01-LCSSA.ll Normal file
View File

@ -0,0 +1,55 @@
; RUN: llvm-as < %s | opt -loop-unswitch -instcombine -disable-output
%struct.ClassDef = type { %struct.QByteArray, %struct.QByteArray, %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", i8, i8, %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", %"struct.QMap<QByteArray,QByteArray>", %"struct.QList<ArgumentDef>", %"struct.QMap<QByteArray,QByteArray>", i32, i32 }
%struct.FILE = type { i32, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, %struct._IO_marker*, %struct.FILE*, i32, i32, i32, i16, i8, [1 x i8], i8*, i64, i8*, i8*, i8*, i8*, i32, i32, [40 x i8] }
%struct.Generator = type { %struct.FILE*, %struct.ClassDef*, %"struct.QList<ArgumentDef>", %struct.QByteArray, %"struct.QList<ArgumentDef>" }
%struct.QBasicAtomic = type { i32 }
%struct.QByteArray = type { %"struct.QByteArray::Data"* }
%"struct.QByteArray::Data" = type { %struct.QBasicAtomic, i32, i32, i8*, [1 x i8] }
%"struct.QList<ArgumentDef>" = type { %"struct.QList<ArgumentDef>::._19" }
%"struct.QList<ArgumentDef>::._19" = type { %struct.QListData }
%struct.QListData = type { %"struct.QListData::Data"* }
%"struct.QListData::Data" = type { %struct.QBasicAtomic, i32, i32, i32, i8, [1 x i8*] }
%"struct.QMap<QByteArray,QByteArray>" = type { %"struct.QMap<QByteArray,QByteArray>::._56" }
%"struct.QMap<QByteArray,QByteArray>::._56" = type { %struct.QMapData* }
%struct.QMapData = type { %struct.QMapData*, [12 x %struct.QMapData*], %struct.QBasicAtomic, i32, i32, i32, i8 }
%struct._IO_marker = type { %struct._IO_marker*, %struct.FILE*, i32 }
@.str9 = external constant [1 x i8] ; <[1 x i8]*> [#uses=1]
declare i32 @strcmp(i8*, i8*)
define i32 @_ZN9Generator6strregEPKc(%struct.Generator* %this, i8* %s) {
entry:
%s_addr.0 = select i1 false, i8* getelementptr ([1 x i8]* @.str9, i32 0, i32 0), i8* %s ; <i8*> [#uses=2]
%tmp122 = icmp eq i8* %s_addr.0, null ; <i1> [#uses=1]
br label %bb184
bb55: ; preds = %bb184
ret i32 0
bb88: ; preds = %bb184
br i1 %tmp122, label %bb154, label %bb128
bb128: ; preds = %bb88
%tmp138 = call i32 @strcmp( i8* null, i8* %s_addr.0 ) ; <i32> [#uses=1]
%iftmp.37.0.in4 = icmp eq i32 %tmp138, 0 ; <i1> [#uses=1]
br i1 %iftmp.37.0.in4, label %bb250, label %bb166
bb154: ; preds = %bb88
br i1 false, label %bb250, label %bb166
bb166: ; preds = %bb154, %bb128
%tmp175 = add i32 %idx.0, 1 ; <i32> [#uses=1]
%tmp177 = add i32 %tmp175, 0 ; <i32> [#uses=1]
%tmp181 = add i32 %tmp177, 0 ; <i32> [#uses=1]
%tmp183 = add i32 %i33.0, 1 ; <i32> [#uses=1]
br label %bb184
bb184: ; preds = %bb166, %entry
%i33.0 = phi i32 [ 0, %entry ], [ %tmp183, %bb166 ] ; <i32> [#uses=2]
%idx.0 = phi i32 [ 0, %entry ], [ %tmp181, %bb166 ] ; <i32> [#uses=2]
%tmp49 = icmp slt i32 %i33.0, 0 ; <i1> [#uses=1]
br i1 %tmp49, label %bb88, label %bb55
bb250: ; preds = %bb154, %bb128
ret i32 %idx.0
}