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Fix a regression from this patch: 

http://mail.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20040308/013095.html

Basically, this patch only updated the immediate dominatees of the header node
to tell them that the preheader also dominated them.  In practice, ALL
dominatees of the header node are also dominated by the preheader.

This fixes: LoopSimplify/2004-03-15-IncorrectDomUpdate.
and PR293

llvm-svn: 12434
This commit is contained in:
Chris Lattner 2004-03-16 06:00:15 +00:00
parent 767858af43
commit db5b8f4d6b
1 changed files with 13 additions and 16 deletions
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29
llvm/lib/Transforms/Scalar/LoopSimplify.cpp
View File

@ -312,31 +312,28 @@ void LoopSimplify::InsertPreheaderForLoop(Loop *L) {
DominatorSet &DS = getAnalysis<DominatorSet>(); // Update dominator info
DominatorTree &DT = getAnalysis<DominatorTree>();
DominatorTree::Node *HeaderDTNode = DT.getNode(Header);
// Update the dominator tree information.
// The immediate dominator of the preheader is the immediate dominator of
// the old header.
DominatorTree::Node *PHDomTreeNode =
DT.createNewNode(NewBB, DT.getNode(Header)->getIDom());
// Change the header node so that PNHode is the new immediate dominator
DT.changeImmediateDominator(DT.getNode(Header), PHDomTreeNode);
{
// The blocks that dominate NewBB are the blocks that dominate Header,
// minus Header, plus NewBB.
DominatorSet::DomSetType DomSet = DS.getDominators(Header);
DomSet.insert(NewBB); // We dominate ourself
DomSet.erase(Header); // Header does not dominate us...
DS.addBasicBlock(NewBB, DomSet);
// The newly created basic block dominates all nodes dominated by Header.
for (DominatorTree::Node::iterator I = HeaderDTNode->begin(),
E = HeaderDTNode->end(); I != E; ++I)
DS.addDominator((*I)->getBlock(), NewBB);
}
{ // Update the dominator tree information.
// The immediate dominator of the preheader is the immediate dominator of
// the old header.
//
DominatorTree::Node *PHNode =
DT.createNewNode(NewBB, HeaderDTNode->getIDom());
// Change the header node so that PNHode is the new immediate dominator
DT.changeImmediateDominator(HeaderDTNode, PHNode);
for (df_iterator<DominatorTree::Node*> DFI = df_begin(PHDomTreeNode),
E = df_end(PHDomTreeNode); DFI != E; ++DFI)
DS.addDominator((*DFI)->getBlock(), NewBB);
}
// Update immediate dominator information if we have it...