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Fix a regression from this patch:

Browse Source 
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


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12434 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-03-16 06:00:15 +00:00
parent 339c50873d
commit 85ebd541fa
1 changed files with 13 additions and 16 deletions
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29
lib/Transforms/Utils/LoopSimplify.cpp
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@ -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...