forked from OSchip/llvm-project
[SimplifyCFG] FoldValueComparisonIntoPredecessors(): switch to non-permissive DomTree updates
... which requires not adding a DomTree edge that we just added.
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@ -17,6 +17,7 @@
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#include "llvm/ADT/Optional.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/ScopeExit.h"
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#include "llvm/ADT/Sequence.h"
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#include "llvm/ADT/SetOperations.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/ADT/SmallPtrSet.h"
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@ -1085,7 +1086,6 @@ static void FitWeights(MutableArrayRef<uint64_t> Weights) {
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/// (either a switch or a branch on "X == c").
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/// See if any of the predecessors of the terminator block are value comparisons
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/// on the same value. If so, and if safe to do so, fold them together.
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// FIXME: switch to non-permissive DomTreeUpdater::applyUpdates().
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bool SimplifyCFGOpt::FoldValueComparisonIntoPredecessors(Instruction *TI,
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IRBuilder<> &Builder) {
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BasicBlock *BB = TI->getParent();
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@ -1129,7 +1129,7 @@ bool SimplifyCFGOpt::FoldValueComparisonIntoPredecessors(Instruction *TI,
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// Based on whether the default edge from PTI goes to BB or not, fill in
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// PredCases and PredDefault with the new switch cases we would like to
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// build.
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SmallVector<BasicBlock *, 8> NewSuccessors;
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SmallMapVector<BasicBlock *, int, 8> NewSuccessors;
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// Update the branch weight metadata along the way
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SmallVector<uint64_t, 8> Weights;
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@ -1185,7 +1185,7 @@ bool SimplifyCFGOpt::FoldValueComparisonIntoPredecessors(Instruction *TI,
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if (PredDefault != BB)
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Updates.push_back({DominatorTree::Delete, Pred, PredDefault});
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PredDefault = BBDefault;
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NewSuccessors.push_back(BBDefault);
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++NewSuccessors[BBDefault];
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}
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unsigned CasesFromPred = Weights.size();
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@ -1194,7 +1194,7 @@ bool SimplifyCFGOpt::FoldValueComparisonIntoPredecessors(Instruction *TI,
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if (!PTIHandled.count(BBCases[i].Value) &&
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BBCases[i].Dest != BBDefault) {
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PredCases.push_back(BBCases[i]);
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NewSuccessors.push_back(BBCases[i].Dest);
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++NewSuccessors[BBCases[i].Dest];
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if (SuccHasWeights || PredHasWeights) {
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// The default weight is at index 0, so weight for the ith case
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// should be at index i+1. Scale the cases from successor by
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@ -1242,7 +1242,7 @@ bool SimplifyCFGOpt::FoldValueComparisonIntoPredecessors(Instruction *TI,
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if (PredHasWeights || SuccHasWeights)
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Weights.push_back(WeightsForHandled[BBCases[i].Value]);
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PredCases.push_back(BBCases[i]);
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NewSuccessors.push_back(BBCases[i].Dest);
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++NewSuccessors[BBCases[i].Dest];
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PTIHandled.erase(
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BBCases[i].Value); // This constant is taken care of
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}
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@ -1253,16 +1253,20 @@ bool SimplifyCFGOpt::FoldValueComparisonIntoPredecessors(Instruction *TI,
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if (PredHasWeights || SuccHasWeights)
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Weights.push_back(WeightsForHandled[I]);
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PredCases.push_back(ValueEqualityComparisonCase(I, BBDefault));
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NewSuccessors.push_back(BBDefault);
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++NewSuccessors[BBDefault];
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}
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}
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// Okay, at this point, we know which new successor Pred will get. Make
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// sure we update the number of entries in the PHI nodes for these
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// successors.
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for (BasicBlock *NewSuccessor : NewSuccessors) {
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AddPredecessorToBlock(NewSuccessor, Pred, BB);
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Updates.push_back({DominatorTree::Insert, Pred, NewSuccessor});
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for (const std::pair<BasicBlock *, int /*Num*/> &NewSuccessor :
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NewSuccessors) {
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for (auto I : seq(0, NewSuccessor.second)) {
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(void)I;
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AddPredecessorToBlock(NewSuccessor.first, Pred, BB);
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}
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Updates.push_back({DominatorTree::Insert, Pred, NewSuccessor.first});
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}
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Builder.SetInsertPoint(PTI);
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@ -1314,7 +1318,7 @@ bool SimplifyCFGOpt::FoldValueComparisonIntoPredecessors(Instruction *TI,
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Updates.push_back({DominatorTree::Delete, Pred, BB});
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if (DTU)
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DTU->applyUpdatesPermissive(Updates);
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DTU->applyUpdates(Updates);
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Changed = true;
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}
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