[llvm-commits] [llvm] r40695 - in /llvm/trunk: lib/Transforms/Scalar/LoopUnswitch.cpp lib/VMCore/Dominators.cpp test/Transforms/LoopUnswitch/2007-08-01-Dom.ll
Devang Patel
dpatel at apple.com
Wed Aug 1 15:23:51 PDT 2007
Author: dpatel
Date: Wed Aug 1 17:23:50 2007
New Revision: 40695
URL: http://llvm.org/viewvc/llvm-project?rev=40695&view=rev
Log:
Update dominator info for the middle blocks created while spliting
exit edge to preserve LCSSA.
Fix dominance frontier update during loop unswitch. This fixes PR 1589.
Added:
llvm/trunk/test/Transforms/LoopUnswitch/2007-08-01-Dom.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp
llvm/trunk/lib/VMCore/Dominators.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp?rev=40695&r1=40694&r2=40695&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp Wed Aug 1 17:23:50 2007
@@ -543,17 +543,8 @@
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 @@
// 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 @@
// 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 @@
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 +760,61 @@
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];
+ 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;
Modified: llvm/trunk/lib/VMCore/Dominators.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/Dominators.cpp?rev=40695&r1=40694&r2=40695&view=diff
==============================================================================
--- llvm/trunk/lib/VMCore/Dominators.cpp (original)
+++ llvm/trunk/lib/VMCore/Dominators.cpp Wed Aug 1 17:23:50 2007
@@ -627,6 +627,15 @@
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 @@
++SetI;
}
- DominanceFrontier::iterator NewBBI = find(NewBB);
if (NewBBI != end()) {
DominanceFrontier::DomSetType NewBBSet = NewBBI->second;
NewBBSet.insert(Set.begin(), Set.end());
Added: llvm/trunk/test/Transforms/LoopUnswitch/2007-08-01-Dom.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnswitch/2007-08-01-Dom.ll?rev=40695&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopUnswitch/2007-08-01-Dom.ll (added)
+++ llvm/trunk/test/Transforms/LoopUnswitch/2007-08-01-Dom.ll Wed Aug 1 17:23:50 2007
@@ -0,0 +1,30 @@
+; RUN: llvm-as < %s | opt -licm -loop-unswitch -disable-output
+; PR 1589
+
+ %struct.QBasicAtomic = type { i32 }
+
+define void @_ZNK5QDate9addMonthsEi(%struct.QBasicAtomic* sret %agg.result, %struct.QBasicAtomic* %this, i32 %nmonths) {
+entry:
+ br label %cond_true90
+
+bb16: ; preds = %cond_true90
+ br i1 false, label %bb93, label %cond_true90
+
+bb45: ; preds = %cond_true90
+ br i1 false, label %bb53, label %bb58
+
+bb53: ; preds = %bb45
+ br i1 false, label %bb93, label %cond_true90
+
+bb58: ; preds = %bb45
+ store i32 0, i32* null, align 4
+ br i1 false, label %cond_true90, label %bb93
+
+cond_true90: ; preds = %bb58, %bb53, %bb16, %entry
+ %nmonths_addr.016.1 = phi i32 [ %nmonths, %entry ], [ 0, %bb16 ], [ 0, %bb53 ], [ %nmonths_addr.016.1, %bb58 ] ; <i32> [#uses=2]
+ %tmp14 = icmp slt i32 %nmonths_addr.016.1, -11 ; <i1> [#uses=1]
+ br i1 %tmp14, label %bb16, label %bb45
+
+bb93: ; preds = %bb58, %bb53, %bb16
+ ret void
+}
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