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Index: lib/CodeGen/MachineBlockPlacement.cpp
===================================================================
--- a/lib/CodeGen/MachineBlockPlacement.cpp
+++ b/lib/CodeGen/MachineBlockPlacement.cpp
@@ -513,6 +513,11 @@
bool runOnMachineFunction(MachineFunction &F) override;
+ bool allowTailDupPlacement() const {
+ assert(F);
+ return TailDupPlacement && !F->getTarget().requiresStructuredCFG();
+ }
+
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<MachineBranchProbabilityInfo>();
AU.addRequired<MachineBlockFrequencyInfo>();
@@ -1018,7 +1023,7 @@
MachineBasicBlock *Succ1 = BestA.Dest;
MachineBasicBlock *Succ2 = BestB.Dest;
// Check to see if tail-duplication would be profitable.
- if (TailDupPlacement && shouldTailDuplicate(Succ2) &&
+ if (allowTailDupPlacement() && shouldTailDuplicate(Succ2) &&
canTailDuplicateUnplacedPreds(BB, Succ2, Chain, BlockFilter) &&
isProfitableToTailDup(BB, Succ2, MBPI->getEdgeProbability(BB, Succ1),
Chain, BlockFilter)) {
@@ -1044,7 +1049,7 @@
return Result;
}
-/// When the option TailDupPlacement is on, this method checks if the
+/// When the option allowTailDupPlacement() is on, this method checks if the
/// fallthrough candidate block \p Succ (of block \p BB) can be tail-duplicated
/// into all of its unplaced, unfiltered predecessors, that are not BB.
bool MachineBlockPlacement::canTailDuplicateUnplacedPreds(
@@ -1493,7 +1498,7 @@
if (hasBetterLayoutPredecessor(BB, Succ, SuccChain, SuccProb, RealSuccProb,
Chain, BlockFilter)) {
// If tail duplication would make Succ profitable, place it.
- if (TailDupPlacement && shouldTailDuplicate(Succ))
+ if (allowTailDupPlacement() && shouldTailDuplicate(Succ))
DupCandidates.push_back(std::make_tuple(SuccProb, Succ));
continue;
}
@@ -1702,7 +1707,7 @@
auto Result = selectBestSuccessor(BB, Chain, BlockFilter);
MachineBasicBlock* BestSucc = Result.BB;
bool ShouldTailDup = Result.ShouldTailDup;
- if (TailDupPlacement)
+ if (allowTailDupPlacement())
ShouldTailDup |= (BestSucc && shouldTailDuplicate(BestSucc));
// If an immediate successor isn't available, look for the best viable
@@ -1724,7 +1729,7 @@
// Placement may have changed tail duplication opportunities.
// Check for that now.
- if (TailDupPlacement && BestSucc && ShouldTailDup) {
+ if (allowTailDupPlacement() && BestSucc && ShouldTailDup) {
// If the chosen successor was duplicated into all its predecessors,
// don't bother laying it out, just go round the loop again with BB as
// the chain end.
@@ -2758,7 +2763,7 @@
TailDupSize = TailDupPlacementAggressiveThreshold;
}
- if (TailDupPlacement) {
+ if (allowTailDupPlacement()) {
MPDT = &getAnalysis<MachinePostDominatorTree>();
if (MF.getFunction().optForSize())
TailDupSize = 1;
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