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[NFC] Add parameter for keeping one-input Phis in DeleteDeadBlock(s) 

llvm-svn: 353799
This commit is contained in:
Max Kazantsev 2019-02-12 06:14:27 +00:00
parent 7670ede434
commit 0686d1ae41
2 changed files with 19 additions and 11 deletions
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14
llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
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@ -41,19 +41,25 @@ class Value;
/// Replace contents of every block in \p BBs with single unreachable
/// instruction. If \p Updates is specified, collect all necessary DT updates
/// into this vector.
/// into this vector. If \p DontDeleteUselessPHIs is true, one-input Phis in
/// successors of blocks being deleted will be preserved.
void DetatchDeadBlocks(ArrayRef <BasicBlock *> BBs,
SmallVectorImpl<DominatorTree::UpdateType> *Updates);
SmallVectorImpl<DominatorTree::UpdateType> *Updates,
bool DontDeleteUselessPHIs = false);
/// Delete the specified block, which must have no predecessors.
void DeleteDeadBlock(BasicBlock *BB, DomTreeUpdater *DTU = nullptr);
void DeleteDeadBlock(BasicBlock *BB, DomTreeUpdater *DTU = nullptr,
bool DontDeleteUselessPHIs = false);
/// Delete the specified blocks from \p BB. The set of deleted blocks must have
/// no predecessors that are not being deleted themselves. \p BBs must have no
/// duplicating blocks. If there are loops among this set of blocks, all
/// relevant loop info updates should be done before this function is called.
/// If \p DontDeleteUselessPHIs is true, one-input Phis in successors of blocks
/// being deleted will be preserved.
void DeleteDeadBlocks(ArrayRef <BasicBlock *> BBs,
DomTreeUpdater *DTU = nullptr);
DomTreeUpdater *DTU = nullptr,
bool DontDeleteUselessPHIs = false);
/// We know that BB has one predecessor. If there are any single-entry PHI nodes
/// in it, fold them away. This handles the case when all entries to the PHI

16
llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
View File

@ -49,13 +49,14 @@ using namespace llvm;
void llvm::DetatchDeadBlocks(
ArrayRef<BasicBlock *> BBs,
SmallVectorImpl<DominatorTree::UpdateType> *Updates) {
SmallVectorImpl<DominatorTree::UpdateType> *Updates,
bool DontDeleteUselessPHIs) {
for (auto *BB : BBs) {
// Loop through all of our successors and make sure they know that one
// of their predecessors is going away.
SmallPtrSet<BasicBlock *, 4> UniqueSuccessors;
for (BasicBlock *Succ : successors(BB)) {
Succ->removePredecessor(BB);
Succ->removePredecessor(BB, DontDeleteUselessPHIs);
if (Updates && UniqueSuccessors.insert(Succ).second)
Updates->push_back({DominatorTree::Delete, BB, Succ});
}
@ -80,12 +81,13 @@ void llvm::DetatchDeadBlocks(
}
}
void llvm::DeleteDeadBlock(BasicBlock *BB, DomTreeUpdater *DTU) {
DeleteDeadBlocks({BB}, DTU);
void llvm::DeleteDeadBlock(BasicBlock *BB, DomTreeUpdater *DTU,
bool DontDeleteUselessPHIs) {
DeleteDeadBlocks({BB}, DTU, DontDeleteUselessPHIs);
}
void llvm::DeleteDeadBlocks(ArrayRef <BasicBlock *> BBs,
DomTreeUpdater *DTU) {
void llvm::DeleteDeadBlocks(ArrayRef <BasicBlock *> BBs, DomTreeUpdater *DTU,
bool DontDeleteUselessPHIs) {
#ifndef NDEBUG
// Make sure that all predecessors of each dead block is also dead.
SmallPtrSet<BasicBlock *, 4> Dead(BBs.begin(), BBs.end());
@ -96,7 +98,7 @@ void llvm::DeleteDeadBlocks(ArrayRef <BasicBlock *> BBs,
#endif
SmallVector<DominatorTree::UpdateType, 4> Updates;
DetatchDeadBlocks(BBs, DTU ? &Updates : nullptr);
DetatchDeadBlocks(BBs, DTU ? &Updates : nullptr, DontDeleteUselessPHIs);
if (DTU)
DTU->applyUpdates(Updates, /*ForceRemoveDuplicates*/ true);