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-rw-r--r--lib/Transforms/Scalar/LoopUnswitch.cpp98
-rw-r--r--lib/VMCore/Dominators.cpp10
-rw-r--r--test/Transforms/LoopUnswitch/2007-08-01-LCSSA.ll55
3 files changed, 141 insertions, 22 deletions
diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp
index 3a10bd7..6b4d637 100644
--- a/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -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);
-
- // 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.
+ new BranchInst(TrueDest, FalseDest, BranchVal, InsertPt);
+
}
@@ -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.
@@ -698,16 +694,21 @@ 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
// original preheader.
F->getBasicBlockList().splice(LoopBlocks[0], F->getBasicBlockList(),
@@ -759,7 +760,62 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
EmitPreheaderBranchOnCondition(LIC, Val, NewBlocks[0], LoopBlocks[0], OldBR);
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;
diff --git a/lib/VMCore/Dominators.cpp b/lib/VMCore/Dominators.cpp
index 9b5ee1b..91b422c 100644
--- a/lib/VMCore/Dominators.cpp
+++ b/lib/VMCore/Dominators.cpp
@@ -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());
diff --git a/test/Transforms/LoopUnswitch/2007-08-01-LCSSA.ll b/test/Transforms/LoopUnswitch/2007-08-01-LCSSA.ll
new file mode 100644
index 0000000..139cdbe
--- /dev/null
+++ b/test/Transforms/LoopUnswitch/2007-08-01-LCSSA.ll
@@ -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
+}
generated by cgit v1.1 at 2025-01-25 01:28:27 +0000