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COWArrayOpt: Fix the array property specializer to recompute the loop tree after cloning

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Cloning the loop is going to invalidate the loop tree. Be conservative and
recompute it.

No test case. I did not run into an error but also don't want to in the future.

Swift SVN r25733
This commit is contained in:
Arnold Schwaighofer
2015-03-04 01:06:27 +00:00
parent 5113456d40
commit 411ba4e830
1 changed files with 20 additions and 12 deletions
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32
lib/SILPasses/COWArrayOpt.cpp
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@@ -1245,7 +1245,6 @@ namespace {
/// However, the client needs to update the dominator of the exit blocks.
class RegionCloner : public SILCloner<RegionCloner> {
DominanceInfo &DomTree;
SILLoopInfo *LoopInfo;
SILBasicBlock *StartBB;
SmallPtrSet<SILBasicBlock *, 16> OutsideBBs;
@@ -1254,11 +1253,9 @@ class RegionCloner : public SILCloner<RegionCloner> {
public:
RegionCloner(SILBasicBlock *EntryBB,
SmallVectorImpl<SILBasicBlock *> &ExitBlocks, DominanceInfo &DT,
SILLoopInfo *LI)
SmallVectorImpl<SILBasicBlock *> &ExitBlocks, DominanceInfo &DT)
: SILCloner<RegionCloner>(*EntryBB->getParent()), DomTree(DT),
LoopInfo(LI), StartBB(EntryBB),
OutsideBBs(ExitBlocks.begin(), ExitBlocks.end()) {}
StartBB(EntryBB), OutsideBBs(ExitBlocks.begin(), ExitBlocks.end()) {}
SILBasicBlock *cloneRegion() {
assert (DomTree.getNode(StartBB) != nullptr && "Can't cloned dead code");
@@ -1409,17 +1406,23 @@ namespace {
/// loop based on array.props calls.
class ArrayPropertiesSpecializer {
DominanceInfo *DomTree;
SILLoopInfo *LoopInfo;
SILLoopAnalysis *LoopAnalysis;
SILBasicBlock *HoistableLoopPreheader;
public:
ArrayPropertiesSpecializer(DominanceInfo *DT, SILLoopInfo *LI,
ArrayPropertiesSpecializer(DominanceInfo *DT, SILLoopAnalysis *LA,
SILBasicBlock *Hoistable)
: DomTree(DT), LoopInfo(LI), HoistableLoopPreheader(Hoistable) {}
: DomTree(DT), LoopAnalysis(LA), HoistableLoopPreheader(Hoistable) {}
void run() {
specializeLoopNest();
}
SILLoop *getLoop() {
auto *LoopInfo =
LoopAnalysis->getLoopInfo(HoistableLoopPreheader->getParent());
return LoopInfo->getLoopFor(HoistableLoopPreheader->getSingleSuccessor());
}
protected:
void specializeLoopNest();
};
@@ -1531,6 +1534,9 @@ static void replaceArrayPropsCall(SILBuilder &B, ArraySemanticsCall C) {
}
void ArrayPropertiesSpecializer::specializeLoopNest() {
auto *Lp = getLoop();
assert(Lp);
// Split of a new empty preheader. We don't want to duplicate the whole
// original preheader it might contain instructions that we can't clone.
// This will be block that will contain the check whether to execute the
@@ -1541,8 +1547,6 @@ void ArrayPropertiesSpecializer::specializeLoopNest() {
// Get the exit blocks of the orignal loop.
auto *Header = CheckBlock->getSingleSuccessor();
assert(Header);
auto *Lp = LoopInfo->getLoopFor(Header);
assert(Lp);
// Our loop info is not really completedly valid anymore since the cloner does
// not update it. However, exit blocks of the original loop are still valid.
@@ -1555,7 +1559,7 @@ void ArrayPropertiesSpecializer::specializeLoopNest() {
// Clone the region from the new preheader up to (not including) the exit
// blocks. This creates a second loop nest.
RegionCloner Cloner(NewPreheader, ExitBlocks, *DomTree, LoopInfo);
RegionCloner Cloner(NewPreheader, ExitBlocks, *DomTree);
auto *ClonedPreheader = Cloner.cloneRegion();
// Collect the array.props call that we will specialize on that we have
@@ -1587,6 +1591,10 @@ void ArrayPropertiesSpecializer::specializeLoopNest() {
SILBuilder B2(ClonedPreheader->getTerminator());
for (auto C : ArrayPropCalls)
replaceArrayPropsCall(B2, C);
// We have potentially cloned a loop - invalidate loop info.
LoopAnalysis->invalidate(Header->getParent(),
SILAnalysis::InvalidationKind::CFG);
}
namespace {
@@ -1630,7 +1638,7 @@ class SwiftArrayOptPass : public SILFunctionTransform {
// Process specialized loop-nests in loop-tree post-order (bottom-up).
std::reverse(HoistableLoopNests.begin(), HoistableLoopNests.end());
for (auto &HoistableLoopNest : HoistableLoopNests)
ArrayPropertiesSpecializer(DT, LI, HoistableLoopNest).run();
ArrayPropertiesSpecializer(DT, LA, HoistableLoopNest).run();
DEBUG(getFunction()->viewCFG());
}