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Avoid spliting loops where two split condition branches are not independent.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41148 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel 2007-08-18 00:00:32 +00:00
parent 7bfd5dba38
commit 20d260a193
1 changed files with 11 additions and 1 deletions
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12
lib/Transforms/Scalar/LoopIndexSplit.cpp
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@ -711,12 +711,22 @@ bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
|| Latch == SplitTerminator->getSuccessor(1)))
return false;
// If one of the split condition branch is post dominating other then loop
// index split is not appropriate.
BasicBlock *Succ0 = SplitTerminator->getSuccessor(0);
BasicBlock *Succ1 = SplitTerminator->getSuccessor(1);
if (DT->dominates(Succ0, Latch) || DT->dominates(Succ1, Latch))
return false;
// If one of the split condition branch is a predecessor of the other
// split condition branch head then do not split loop on this condition.
for(pred_iterator PI = pred_begin(Succ0), PE = pred_end(Succ0); PI != PE; ++PI)
if (Succ1 == *PI)
return false;
for(pred_iterator PI = pred_begin(Succ1), PE = pred_end(Succ1); PI != PE; ++PI)
if (Succ0 == *PI)
return false;
// True loop is original loop. False loop is cloned loop.
bool SignedPredicate = ExitCondition->isSignedPredicate();