summaryrefslogtreecommitdiffstats
path: root/contrib/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'contrib/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp')
-rw-r--r--contrib/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp43
1 files changed, 29 insertions, 14 deletions
diff --git a/contrib/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp b/contrib/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
index f752d79..2a8e9b8 100644
--- a/contrib/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
+++ b/contrib/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
@@ -117,33 +117,38 @@ bool llvm::isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
return false;
}
-/// CreatePHIsForSplitLoopExit - When a loop exit edge is split, LCSSA form
+/// createPHIsForSplitLoopExit - When a loop exit edge is split, LCSSA form
/// may require new PHIs in the new exit block. This function inserts the
-/// new PHIs, as needed. Preds is a list of preds inside the loop, SplitBB
+/// new PHIs, as needed. Preds is a list of preds inside the loop, SplitBB
/// is the new loop exit block, and DestBB is the old loop exit, now the
/// successor of SplitBB.
-static void CreatePHIsForSplitLoopExit(SmallVectorImpl<BasicBlock *> &Preds,
+static void createPHIsForSplitLoopExit(SmallVectorImpl<BasicBlock *> &Preds,
BasicBlock *SplitBB,
BasicBlock *DestBB) {
// SplitBB shouldn't have anything non-trivial in it yet.
- assert(SplitBB->getFirstNonPHI() == SplitBB->getTerminator() &&
- "SplitBB has non-PHI nodes!");
+ assert((SplitBB->getFirstNonPHI() == SplitBB->getTerminator() ||
+ SplitBB->isLandingPad()) && "SplitBB has non-PHI nodes!");
- // For each PHI in the destination block...
+ // For each PHI in the destination block.
for (BasicBlock::iterator I = DestBB->begin();
PHINode *PN = dyn_cast<PHINode>(I); ++I) {
unsigned Idx = PN->getBasicBlockIndex(SplitBB);
Value *V = PN->getIncomingValue(Idx);
+
// If the input is a PHI which already satisfies LCSSA, don't create
// a new one.
if (const PHINode *VP = dyn_cast<PHINode>(V))
if (VP->getParent() == SplitBB)
continue;
+
// Otherwise a new PHI is needed. Create one and populate it.
- PHINode *NewPN = PHINode::Create(PN->getType(), Preds.size(), "split",
- SplitBB->getTerminator());
+ PHINode *NewPN =
+ PHINode::Create(PN->getType(), Preds.size(), "split",
+ SplitBB->isLandingPad() ?
+ SplitBB->begin() : SplitBB->getTerminator());
for (unsigned i = 0, e = Preds.size(); i != e; ++i)
NewPN->addIncoming(V, Preds[i]);
+
// Update the original PHI.
PN->setIncomingValue(Idx, NewPN);
}
@@ -168,7 +173,8 @@ static void CreatePHIsForSplitLoopExit(SmallVectorImpl<BasicBlock *> &Preds,
///
BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum,
Pass *P, bool MergeIdenticalEdges,
- bool DontDeleteUselessPhis) {
+ bool DontDeleteUselessPhis,
+ bool SplitLandingPads) {
if (!isCriticalEdge(TI, SuccNum, MergeIdenticalEdges)) return 0;
assert(!isa<IndirectBrInst>(TI) &&
@@ -338,7 +344,7 @@ BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum,
if (P->mustPreserveAnalysisID(LCSSAID)) {
SmallVector<BasicBlock *, 1> OrigPred;
OrigPred.push_back(TIBB);
- CreatePHIsForSplitLoopExit(OrigPred, NewBB, DestBB);
+ createPHIsForSplitLoopExit(OrigPred, NewBB, DestBB);
}
// For each unique exit block...
@@ -371,10 +377,19 @@ BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum,
// getUniqueExitBlocks above because that depends on LoopSimplify
// form, which we're in the process of restoring!
if (!Preds.empty() && HasPredOutsideOfLoop) {
- BasicBlock *NewExitBB =
- SplitBlockPredecessors(Exit, Preds, "split", P);
- if (P->mustPreserveAnalysisID(LCSSAID))
- CreatePHIsForSplitLoopExit(Preds, NewExitBB, Exit);
+ if (!Exit->isLandingPad()) {
+ BasicBlock *NewExitBB =
+ SplitBlockPredecessors(Exit, Preds, "split", P);
+ if (P->mustPreserveAnalysisID(LCSSAID))
+ createPHIsForSplitLoopExit(Preds, NewExitBB, Exit);
+ } else if (SplitLandingPads) {
+ SmallVector<BasicBlock*, 8> NewBBs;
+ SplitLandingPadPredecessors(Exit, Preds,
+ ".split1", ".split2",
+ P, NewBBs);
+ if (P->mustPreserveAnalysisID(LCSSAID))
+ createPHIsForSplitLoopExit(Preds, NewBBs[0], Exit);
+ }
}
}
}
OpenPOWER on IntegriCloud