From 5d5cc59cc77afe655b3707cb0e69e0827b444cad Mon Sep 17 00:00:00 2001
From: dim <dim@FreeBSD.org>
Date: Fri, 17 Sep 2010 15:48:55 +0000
Subject: Vendor import of llvm r114020 (from the release_28 branch):
http://llvm.org/svn/llvm-project/llvm/branches/release_28@114020
Approved by: rpaulo (mentor)
---
lib/CodeGen/MachineBasicBlock.cpp | 32 +++++++++++++++++++++++++++-----
1 file changed, 27 insertions(+), 5 deletions(-)
(limited to 'lib/CodeGen/MachineBasicBlock.cpp')
diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index a27ee47..50f3f67 100644
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -441,7 +441,7 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) {
MachineBasicBlock *NMBB = MF->CreateMachineBasicBlock();
MF->insert(llvm::next(MachineFunction::iterator(this)), NMBB);
- DEBUG(dbgs() << "PHIElimination splitting critical edge:"
+ DEBUG(dbgs() << "Splitting critical edge:"
" BB#" << getNumber()
<< " -- BB#" << NMBB->getNumber()
<< " -- BB#" << Succ->getNumber() << '\n');
@@ -468,11 +468,33 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) {
LV->addNewBlock(NMBB, this, Succ);
if (MachineDominatorTree *MDT =
- P->getAnalysisIfAvailable<MachineDominatorTree>())
- MDT->addNewBlock(NMBB, this);
+ P->getAnalysisIfAvailable<MachineDominatorTree>()) {
+ // Update dominator information.
+ MachineDomTreeNode *SucccDTNode = MDT->getNode(Succ);
+
+ bool IsNewIDom = true;
+ for (const_pred_iterator PI = Succ->pred_begin(), E = Succ->pred_end();
+ PI != E; ++PI) {
+ MachineBasicBlock *PredBB = *PI;
+ if (PredBB == NMBB)
+ continue;
+ if (!MDT->dominates(SucccDTNode, MDT->getNode(PredBB))) {
+ IsNewIDom = false;
+ break;
+ }
+ }
+
+ // We know "this" dominates the newly created basic block.
+ MachineDomTreeNode *NewDTNode = MDT->addNewBlock(NMBB, this);
+
+ // If all the other predecessors of "Succ" are dominated by "Succ" itself
+ // then the new block is the new immediate dominator of "Succ". Otherwise,
+ // the new block doesn't dominate anything.
+ if (IsNewIDom)
+ MDT->changeImmediateDominator(SucccDTNode, NewDTNode);
+ }
- if (MachineLoopInfo *MLI =
- P->getAnalysisIfAvailable<MachineLoopInfo>())
+ if (MachineLoopInfo *MLI = P->getAnalysisIfAvailable<MachineLoopInfo>())
if (MachineLoop *TIL = MLI->getLoopFor(this)) {
// If one or the other blocks were not in a loop, the new block is not
// either, and thus LI doesn't need to be updated.
--
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