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[NFC] Tweak SplitBlockAndInsertIfThen to use existing ThenBlock 

llvm-svn: 354107
This commit is contained in:
Max Kazantsev 2019-02-15 08:18:00 +00:00
parent 0af864b4b2
commit 73db5c137a
2 changed files with 20 additions and 10 deletions
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6
llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
View File

@ -270,7 +270,8 @@ ReturnInst *FoldReturnIntoUncondBranch(ReturnInst *RI, BasicBlock *BB,
/// SplitBefore
/// Tail
///
/// If Unreachable is true, then ThenBlock ends with
/// If \p ThenBlock is not specified, a new block will be created for it.
/// If \p Unreachable is true, the newly created block will end with
/// UnreachableInst, otherwise it branches to Tail.
/// Returns the NewBasicBlock's terminator.
///
@ -279,7 +280,8 @@ Instruction *SplitBlockAndInsertIfThen(Value *Cond, Instruction *SplitBefore,
bool Unreachable,
MDNode *BranchWeights = nullptr,
DominatorTree *DT = nullptr,
LoopInfo *LI = nullptr);
LoopInfo *LI = nullptr,
BasicBlock *ThenBlock = nullptr);
/// SplitBlockAndInsertIfThenElse is similar to SplitBlockAndInsertIfThen,
/// but also creates the ElseBlock.

24
llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
View File

@ -730,18 +730,23 @@ Instruction *llvm::SplitBlockAndInsertIfThen(Value *Cond,
Instruction *SplitBefore,
bool Unreachable,
MDNode *BranchWeights,
DominatorTree *DT, LoopInfo *LI) {
DominatorTree *DT, LoopInfo *LI,
BasicBlock *ThenBlock) {
BasicBlock *Head = SplitBefore->getParent();
BasicBlock *Tail = Head->splitBasicBlock(SplitBefore->getIterator());
Instruction *HeadOldTerm = Head->getTerminator();
LLVMContext &C = Head->getContext();
BasicBlock *ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
Instruction *CheckTerm;
if (Unreachable)
CheckTerm = new UnreachableInst(C, ThenBlock);
else
CheckTerm = BranchInst::Create(Tail, ThenBlock);
CheckTerm->setDebugLoc(SplitBefore->getDebugLoc());
bool CreateThenBlock = (ThenBlock == nullptr);
if (CreateThenBlock) {
ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
if (Unreachable)
CheckTerm = new UnreachableInst(C, ThenBlock);
else
CheckTerm = BranchInst::Create(Tail, ThenBlock);
CheckTerm->setDebugLoc(SplitBefore->getDebugLoc());
} else
CheckTerm = ThenBlock->getTerminator();
BranchInst *HeadNewTerm =
BranchInst::Create(/*ifTrue*/ThenBlock, /*ifFalse*/Tail, Cond);
HeadNewTerm->setMetadata(LLVMContext::MD_prof, BranchWeights);
@ -756,7 +761,10 @@ Instruction *llvm::SplitBlockAndInsertIfThen(Value *Cond,
DT->changeImmediateDominator(Child, NewNode);
// Head dominates ThenBlock.
DT->addNewBlock(ThenBlock, Head);
if (CreateThenBlock)
DT->addNewBlock(ThenBlock, Head);
else
DT->changeImmediateDominator(ThenBlock, Head);
}
}