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[SmallPtrSet] Optimize find/erase #104740

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merged 1 commit into from
Aug 19, 2024
Merged

[SmallPtrSet] Optimize find/erase #104740

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8 changes: 4 additions & 4 deletions llvm/include/llvm/ADT/SmallPtrSet.h
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Original file line number Diff line number Diff line change
Expand Up @@ -185,8 +185,8 @@ class SmallPtrSetImplBase : public DebugEpochBase {
return false;
}

auto *Bucket = FindBucketFor(Ptr);
if (*Bucket != Ptr)
auto *Bucket = doFind(Ptr);
if (!Bucket)
return false;

*const_cast<const void **>(Bucket) = getTombstoneMarker();
Expand All @@ -211,8 +211,7 @@ class SmallPtrSetImplBase : public DebugEpochBase {
}

// Big set case.
auto *Bucket = FindBucketFor(Ptr);
if (*Bucket == Ptr)
if (auto *Bucket = doFind(Ptr))
return Bucket;
return EndPointer();
}
Expand All @@ -222,6 +221,7 @@ class SmallPtrSetImplBase : public DebugEpochBase {
private:
std::pair<const void *const *, bool> insert_imp_big(const void *Ptr);

const void *const *doFind(const void *Ptr) const;
const void * const *FindBucketFor(const void *Ptr) const;
void shrink_and_clear();

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20 changes: 19 additions & 1 deletion llvm/lib/Support/SmallPtrSet.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,25 @@ SmallPtrSetImplBase::insert_imp_big(const void *Ptr) {
return std::make_pair(Bucket, true);
}

const void * const *SmallPtrSetImplBase::FindBucketFor(const void *Ptr) const {
const void *const *SmallPtrSetImplBase::doFind(const void *Ptr) const {
unsigned BucketNo =
DenseMapInfo<void *>::getHashValue(Ptr) & (CurArraySize - 1);
unsigned ProbeAmt = 1;
while (true) {
const void *const *Bucket = CurArray + BucketNo;
if (LLVM_LIKELY(*Bucket == Ptr))
return Bucket;
if (LLVM_LIKELY(*Bucket == getEmptyMarker()))
return nullptr;

// Otherwise, it's a hash collision or a tombstone, continue quadratic
// probing.
BucketNo += ProbeAmt++;
BucketNo &= CurArraySize - 1;
}
}

const void *const *SmallPtrSetImplBase::FindBucketFor(const void *Ptr) const {
unsigned Bucket = DenseMapInfo<void *>::getHashValue(Ptr) & (CurArraySize-1);
unsigned ArraySize = CurArraySize;
unsigned ProbeAmt = 1;
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