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Fix bug: LoopPreheaders/2003-05-12-PreheaderExitOfChild.ll 

llvm-svn: 6153
This commit is contained in:
Chris Lattner 2003-05-12 22:04:34 +00:00
parent a7aebc9b2c
commit 0895025b30
1 changed files with 19 additions and 5 deletions
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24
llvm/lib/Transforms/Scalar/LoopSimplify.cpp
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@ -167,6 +167,19 @@ BasicBlock *Preheaders::SplitBlockPredecessors(BasicBlock *BB,
return NewBB;
}
// ChangeExitBlock - This recursive function is used to change any exit blocks
// that use OldExit to use NewExit instead. This is recursive because children
// may need to be processed as well.
//
static void ChangeExitBlock(Loop *L, BasicBlock *OldExit, BasicBlock *NewExit) {
if (L->hasExitBlock(OldExit)) {
L->changeExitBlock(OldExit, NewExit);
const std::vector<Loop*> &SubLoops = L->getSubLoops();
for (unsigned i = 0, e = SubLoops.size(); i != e; ++i)
ChangeExitBlock(SubLoops[i], OldExit, NewExit);
}
}
/// InsertPreheaderForLoop - Once we discover that a loop doesn't have a
/// preheader, this method is called to insert one. This method has two phases:
@ -197,18 +210,19 @@ void Preheaders::InsertPreheaderForLoop(Loop *L) {
// If the header for the loop used to be an exit node for another loop, then
// we need to update this to know that the loop-preheader is now the exit
// node. Note that the only loop that could have our header as an exit node
// is a sibling loop, ie, one with the same parent loop.
// is a sibling loop, ie, one with the same parent loop, or one if it's
// children.
//
const std::vector<Loop*> *ParentSubLoops;
if (Loop *Parent = L->getParentLoop())
ParentSubLoops = &Parent->getSubLoops();
else // Must check top-level loops...
ParentSubLoops = &getAnalysis<LoopInfo>().getTopLevelLoops();
// Loop over all sibling loops, performing the substitution...
// Loop over all sibling loops, performing the substitution (recursively to
// include child loops)...
for (unsigned i = 0, e = ParentSubLoops->size(); i != e; ++i)
if ((*ParentSubLoops)[i]->hasExitBlock(Header))
(*ParentSubLoops)[i]->changeExitBlock(Header, NewBB);
ChangeExitBlock((*ParentSubLoops)[i], Header, NewBB);
DominatorSet &DS = getAnalysis<DominatorSet>(); // Update dominator info
{