From 4a2dec05cef5882b745dd248d79e42a42cdbc87b Mon Sep 17 00:00:00 2001 From: Evgeniy Stepanov Date: Fri, 19 Oct 2012 10:48:31 +0000 Subject: Move SplitBlockAndInsertIfThen to BasicBlockUtils. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166278 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Utils/BasicBlockUtils.cpp | 39 ++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) (limited to 'lib/Transforms/Utils/BasicBlockUtils.cpp') diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp index edeebe1b79..9fea11391a 100644 --- a/lib/Transforms/Utils/BasicBlockUtils.cpp +++ b/lib/Transforms/Utils/BasicBlockUtils.cpp @@ -687,3 +687,42 @@ ReturnInst *llvm::FoldReturnIntoUncondBranch(ReturnInst *RI, BasicBlock *BB, return cast(NewRet); } +/// SplitBlockAndInsertIfThen - Split the containing block at the +/// specified instruction - everything before and including Cmp stays +/// in the old basic block, and everything after Cmp is moved to a +/// new block. The two blocks are connected by a conditional branch +/// (with value of Cmp being the condition). +/// Before: +/// Head +/// Cmp +/// Tail +/// After: +/// Head +/// Cmp +/// if (Cmp) +/// ThenBlock +/// Tail +/// +/// If Unreachable is true, then ThenBlock ends with +/// UnreachableInst, otherwise it branches to Tail. +/// Returns the NewBasicBlock's terminator. + +TerminatorInst *llvm::SplitBlockAndInsertIfThen(Instruction *Cmp, + bool Unreachable, MDNode *BranchWeights) { + Instruction *SplitBefore = Cmp->getNextNode(); + BasicBlock *Head = SplitBefore->getParent(); + BasicBlock *Tail = Head->splitBasicBlock(SplitBefore); + TerminatorInst *HeadOldTerm = Head->getTerminator(); + LLVMContext &C = Head->getContext(); + BasicBlock *ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail); + TerminatorInst *CheckTerm; + if (Unreachable) + CheckTerm = new UnreachableInst(C, ThenBlock); + else + CheckTerm = BranchInst::Create(Tail, ThenBlock); + BranchInst *HeadNewTerm = + BranchInst::Create(/*ifTrue*/ThenBlock, /*ifFalse*/Tail, Cmp); + HeadNewTerm->setMetadata(LLVMContext::MD_prof, BranchWeights); + ReplaceInstWithInst(HeadOldTerm, HeadNewTerm); + return CheckTerm; +} -- cgit v1.2.3-18-g5258