[llvm-commits] [llvm] r40024 - /llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp
Devang Patel
dpatel at apple.com
Wed Jul 18 16:48:20 PDT 2007
Author: dpatel
Date: Wed Jul 18 18:48:20 2007
New Revision: 40024
URL: http://llvm.org/viewvc/llvm-project?rev=40024&view=rev
Log:
Fix dominator info update to accommodate CFG changes.
This fixes PR1559.
Modified:
llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp?rev=40024&r1=40023&r2=40024&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp Wed Jul 18 18:48:20 2007
@@ -408,26 +408,70 @@
}
// CloneDomInfo - NewBB is cloned from Orig basic block. Now clone Dominator Info.
-// If Orig is in Loop then find and use Orig dominator's cloned block as NewBB
-// dominator.
-void CloneDomInfo(BasicBlock *NewBB, BasicBlock *Orig, Loop *L,
+//
+// If Orig block's immediate dominator is mapped in VM then use corresponding
+// immediate dominator from the map. Otherwise Orig block's dominator is also
+// NewBB's dominator.
+//
+// OrigPreheader is loop pre-header before this patch started
+// updating CFG. NewPrehader is loops new pre-header. However, after CFG
+// manipulation, loop L may not exist. So rely in input parameter NewPreheader.
+void CloneDomInfo(BasicBlock *NewBB, BasicBlock *Orig,
+ BasicBlock *NewPreheader, BasicBlock *OrigPreheader,
+ BasicBlock *OrigHeader,
DominatorTree *DT, DominanceFrontier *DF,
DenseMap<const Value*, Value*> &VM) {
+ // If NewBB alreay has found its place in domiantor tree then no need to do
+ // anything.
+ if (DT->getNode(NewBB))
+ return;
+
+ // If Orig does not have any immediate domiantor then its clone, NewBB, does
+ // not need any immediate dominator.
DomTreeNode *OrigNode = DT->getNode(Orig);
if (!OrigNode)
return;
- BasicBlock *OrigIDom = OrigNode->getBlock();
- BasicBlock *NewIDom = OrigIDom;
- if (L->contains(OrigIDom)) {
- if (!DT->getNode(OrigIDom))
- CloneDomInfo(NewIDom, OrigIDom, L, DT, DF, VM);
- NewIDom = cast<BasicBlock>(VM[OrigIDom]);
- }
- if (NewBB == NewIDom) {
- DT->addNewBlock(NewBB, OrigIDom);
- DT->changeImmediateDominator(NewBB, NewIDom);
- } else
+ DomTreeNode *OrigIDomNode = OrigNode->getIDom();
+ if (!OrigIDomNode)
+ return;
+
+ BasicBlock *OrigIDom = NULL;
+
+ // If Orig is original loop header then its immediate dominator is
+ // NewPreheader.
+ if (Orig == OrigHeader)
+ OrigIDom = NewPreheader;
+
+ // If Orig is new pre-header then its immediate dominator is
+ // original pre-header.
+ else if (Orig == NewPreheader)
+ OrigIDom = OrigPreheader;
+
+ // Other as DT to find Orig's immediate dominator.
+ else
+ OrigIDom = OrigIDomNode->getBlock();
+
+ // Initially use Orig's immediate dominator as NewBB's immediate dominator.
+ BasicBlock *NewIDom = OrigIDom;
+ DenseMap<const Value*, Value*>::iterator I = VM.find(OrigIDom);
+ if (I != VM.end()) {
+ // if (!DT->getNode(OrigIDom))
+ // CloneDomInfo(NewIDom, OrigIDom, NewPreheader, OrigPreheader,
+ // OrigHeader, DT, DF, VM);
+
+ NewIDom = cast<BasicBlock>(I->second);
+
+ // If NewIDom does not have corresponding dominatore tree node then
+ // get one.
+ if (!DT->getNode(NewIDom))
+ CloneDomInfo(NewIDom, OrigIDom, NewPreheader, OrigPreheader,
+ OrigHeader, DT, DF, VM);
+ }
+ // if (NewBB == NewIDom) {
+ // DT->addNewBlock(NewBB, OrigIDom);
+ // DT->changeImmediateDominator(NewBB, NewIDom);
+ //} else
DT->addNewBlock(NewBB, NewIDom);
DominanceFrontier::DomSetType NewDFSet;
@@ -438,8 +482,9 @@
for (DominanceFrontier::DomSetType::iterator I = S.begin(), E = S.end();
I != E; ++I) {
BasicBlock *BB = *I;
- if (L->contains(BB))
- NewDFSet.insert(cast<BasicBlock>(VM[Orig]));
+ DenseMap<const Value*, Value*>::iterator I = VM.find(BB);
+ if (I != VM.end())
+ NewDFSet.insert(cast<BasicBlock>(I->second));
else
NewDFSet.insert(BB);
}
@@ -564,8 +609,10 @@
// First step, split the preheader and exit blocks, and add these blocks to
// the LoopBlocks list.
+ BasicBlock *OrigHeader = L->getHeader();
BasicBlock *OrigPreheader = L->getLoopPreheader();
- LoopBlocks.push_back(SplitEdge(OrigPreheader, L->getHeader(), this));
+ BasicBlock *NewPreheader = SplitEdge(OrigPreheader, L->getHeader(), this);
+ LoopBlocks.push_back(NewPreheader);
// We want the loop to come after the preheader, but before the exit blocks.
LoopBlocks.insert(LoopBlocks.end(), L->block_begin(), L->block_end());
@@ -643,7 +690,8 @@
for (unsigned i = 0, e = LoopBlocks.size(); i != e; ++i) {
BasicBlock *LBB = LoopBlocks[i];
BasicBlock *NBB = NewBlocks[i];
- CloneDomInfo(NBB, LBB, L, DT, DF, ValueMap);
+ CloneDomInfo(NBB, LBB, NewPreheader, OrigPreheader,
+ OrigHeader, DT, DF, ValueMap);
}
// Splice the newly inserted blocks into the function right before the
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