diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index c3343ed8ecc..bcea927925b 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -5733,9 +5733,12 @@ bool SimplifyCFGOpt::SimplifyUncondBranch(BranchInst *BI, // header. (This is for early invocations before loop simplify and // vectorization to keep canonical loop forms for nested loops. These blocks // can be eliminated when the pass is invoked later in the back-end.) + // Note that if BB has only one predecessor then we do not introduce new + // backedge, so we can eliminate BB. bool NeedCanonicalLoop = Options.NeedCanonicalLoop && - (LoopHeaders && (LoopHeaders->count(BB) || LoopHeaders->count(Succ))); + (LoopHeaders && !BB->getSinglePredecessor() && + (LoopHeaders->count(BB) || LoopHeaders->count(Succ))); BasicBlock::iterator I = BB->getFirstNonPHIOrDbg()->getIterator(); if (I->isTerminator() && BB != &BB->getParent()->getEntryBlock() && !NeedCanonicalLoop && TryToSimplifyUncondBranchFromEmptyBlock(BB)) |
