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-rw-r--r--llvm/lib/Transforms/Utils/SimplifyCFG.cpp16
1 files changed, 9 insertions, 7 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index dee658f9839..8784b970214 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -5656,20 +5656,22 @@ static bool TryToMergeLandingPad(LandingPadInst *LPad, BranchInst *BI,
bool SimplifyCFGOpt::SimplifyUncondBranch(BranchInst *BI,
IRBuilder<> &Builder) {
BasicBlock *BB = BI->getParent();
+ BasicBlock *Succ = BI->getSuccessor(0);
if (SinkCommon && SinkThenElseCodeToEnd(BI))
return true;
// If the Terminator is the only non-phi instruction, simplify the block.
- // if LoopHeader is provided, check if the block is a loop 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.)
+ // if LoopHeader is provided, check if the block or its successor is a loop
+ // 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.)
+ bool NeedCanonicalLoop =
+ !LateSimplifyCFG &&
+ (LoopHeaders && (LoopHeaders->count(BB) || LoopHeaders->count(Succ)));
BasicBlock::iterator I = BB->getFirstNonPHIOrDbg()->getIterator();
if (I->isTerminator() && BB != &BB->getParent()->getEntryBlock() &&
- (!LoopHeaders || !LoopHeaders->count(BB)) &&
- TryToSimplifyUncondBranchFromEmptyBlock(BB))
+ !NeedCanonicalLoop && TryToSimplifyUncondBranchFromEmptyBlock(BB))
return true;
// If the only instruction in the block is a seteq/setne comparison
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