On Sun, 2007-01-14 at 12:33 -0600, Chris Lattner wrote:
>
> Changes in directory llvm/lib/Transforms/Utils:
>
> BreakCriticalEdges.cpp updated: 1.38 -> 1.39
> ---
> Log message:
>
> Fix PR1110: http://llvm.org/PR1110 and
> Analysis/Dominators/2007-01-14-BreakCritEdges.ll by being
> more careful about unreachable code when updating dominator info.
I believe this patch has now broken:
test/Regression/Analysis/Dominators/2006-10-02-BreakCritEdges.ll
It is reporting:
Printing analysis 'Dominator Tree Construction' for function 'f':
=============================--------------------------------
Inorder Dominator Tree:
[1] %entry
[2] %brtrue
[3] %brtrue.brfalse_crit_edge
[3] %brtrue.brtrue_crit_edge
[2] %brfalse
which doesn't match the expected pattern of grep '3.*%brtrue$'
I'm unsure of whether this is an intended change and the test case
should be updated or whether the test case is correct and the patch
broke -break-crit-edges.
Reid.
>
>
> ---
> Diffs of the changes: (+40 -35)
>
> BreakCriticalEdges.cpp | 75
> ++++++++++++++++++++++++++-----------------------
> 1 files changed, 40 insertions(+), 35 deletions(-)
>
>
> Index: llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
> diff -u llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp:1.38
> llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp:1.39
> --- llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp:1.38 Tue Dec 19
> 16:17:40 2006
> +++ llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp Sun Jan 14 12:33:35 2007
> @@ -182,49 +182,54 @@
>
> // Should we update DominatorSet information?
> if (DominatorSet *DS = P->getAnalysisToUpdate<DominatorSet>()) {
> - // The blocks that dominate the new one are the blocks that dominate TIBB
> - // plus the new block itself.
> - DominatorSet::DomSetType DomSet = DS->getDominators(TIBB);
> - DomSet.insert(NewBB); // A block always dominates itself.
> - DS->addBasicBlock(NewBB, DomSet);
> -
> - // If NewBBDominatesDestBB hasn't been computed yet, do so with DS.
> - if (!OtherPreds.empty()) {
> - while (!OtherPreds.empty() && NewBBDominatesDestBB) {
> - NewBBDominatesDestBB = DS->dominates(DestBB, OtherPreds.back());
> - OtherPreds.pop_back();
> + DominatorSet::iterator DSI = DS->find(TIBB);
> + if (DSI != DS->end()) { // TIBB is reachable?
> + // The blocks that dominate the new one are the blocks that dominate
> TIBB
> + // plus the new block itself.
> + DominatorSet::DomSetType DomSet = DSI->second; // Copy domset.
> + DomSet.insert(NewBB); // A block always dominates itself.
> + DS->addBasicBlock(NewBB, DomSet);
> +
> + // If NewBBDominatesDestBB hasn't been computed yet, do so with DS.
> + if (!OtherPreds.empty()) {
> + while (!OtherPreds.empty() && NewBBDominatesDestBB) {
> + NewBBDominatesDestBB = DS->dominates(DestBB, OtherPreds.back());
> + OtherPreds.pop_back();
> + }
> + OtherPreds.clear();
> + }
> +
> + // If NewBBDominatesDestBB, then NewBB dominates DestBB, otherwise it
> + // doesn't dominate anything. If NewBB does dominates DestBB, then it
> + // dominates everything that DestBB dominates.
> + if (NewBBDominatesDestBB) {
> + for (DominatorSet::iterator I = DS->begin(), E = DS->end(); I != E;
> ++I)
> + if (I->second.count(DestBB))
> + I->second.insert(NewBB);
> }
> - OtherPreds.clear();
> - }
> -
> - // If NewBBDominatesDestBB, then NewBB dominates DestBB, otherwise it
> - // doesn't dominate anything. If NewBB does dominates DestBB, then it
> - // dominates everything that DestBB dominates.
> - if (NewBBDominatesDestBB) {
> - for (DominatorSet::iterator I = DS->begin(), E = DS->end(); I != E;
> ++I)
> - if (I->second.count(DestBB))
> - I->second.insert(NewBB);
> }
> }
>
> // Should we update ImmediateDominator information?
> if (ImmediateDominators *ID =
> P->getAnalysisToUpdate<ImmediateDominators>()) {
> - // TIBB is the new immediate dominator for NewBB.
> - ID->addNewBlock(NewBB, TIBB);
> -
> - // If NewBBDominatesDestBB hasn't been computed yet, do so with ID.
> - if (!OtherPreds.empty()) {
> - while (!OtherPreds.empty() && NewBBDominatesDestBB) {
> - NewBBDominatesDestBB = ID->dominates(DestBB, OtherPreds.back());
> - OtherPreds.pop_back();
> + if (ID->get(TIBB)) { // Only do this if TIBB is reachable.
> + // TIBB is the new immediate dominator for NewBB.
> + ID->addNewBlock(NewBB, TIBB);
> +
> + // If NewBBDominatesDestBB hasn't been computed yet, do so with ID.
> + if (!OtherPreds.empty()) {
> + while (!OtherPreds.empty() && NewBBDominatesDestBB) {
> + NewBBDominatesDestBB = ID->dominates(DestBB, OtherPreds.back());
> + OtherPreds.pop_back();
> + }
> + OtherPreds.clear();
> }
> - OtherPreds.clear();
> +
> + // If NewBBDominatesDestBB, then NewBB dominates DestBB, otherwise it
> + // doesn't dominate anything.
> + if (NewBBDominatesDestBB)
> + ID->setImmediateDominator(DestBB, NewBB);
> }
> -
> - // If NewBBDominatesDestBB, then NewBB dominates DestBB, otherwise it
> - // doesn't dominate anything.
> - if (NewBBDominatesDestBB)
> - ID->setImmediateDominator(DestBB, NewBB);
> }
>
> // Update the forest?
>
>
>
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