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Switch to using SuperFastHash instead of adding all elements together. This

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doesn't significantly improve performance but it helps a small amount.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29642 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2006-08-12 01:07:10 +00:00
parent 4477185a6e
commit dd28900168
1 changed files with 24 additions and 6 deletions
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28
lib/CodeGen/SelectionDAG/SelectionDAGCSEMap.cpp
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@@ -126,10 +126,23 @@ void SelectionDAGCSEMap::NodeID::SetOperands(const SDOperand *Ops,
/// ComputeHash - Compute a strong hash value for this NodeID, for lookup in /// ComputeHash - Compute a strong hash value for this NodeID, for lookup in
/// the SelectionDAGCSEMap. /// the SelectionDAGCSEMap.
unsigned SelectionDAGCSEMap::NodeID::ComputeHash() const { unsigned SelectionDAGCSEMap::NodeID::ComputeHash() const {
// FIXME: this hash function sucks. // This is adapted from SuperFastHash by Paul Hsieh.
unsigned Hash = 0; unsigned Hash = Bits.size();
for (unsigned i = 0, e = Bits.size(); i != e; ++i) for (const unsigned *BP = &Bits[0], *E = BP+Bits.size(); BP != E; ++BP) {
Hash = Hash+Bits[i]; unsigned Data = *BP;
Hash += Data & 0xFFFF;
unsigned Tmp = ((Data >> 16) << 11) ^ Hash;
Hash = (Hash << 16) ^ Tmp;
Hash += Hash >> 11;
}
// Force "avalanching" of final 127 bits.
Hash ^= Hash << 3;
Hash += Hash >> 5;
Hash ^= Hash << 4;
Hash += Hash >> 17;
Hash ^= Hash << 25;
Hash += Hash >> 6;
return Hash; return Hash;
} }
@@ -142,7 +155,7 @@ bool SelectionDAGCSEMap::NodeID::operator==(const NodeID &RHS) const {
//===----------------------------------------------------------------------===// //===----------------------------------------------------------------------===//
// SelectionDAGCSEMap Implementation // SelectionDAGCSEMap Implementation
SelectionDAGCSEMap::SelectionDAGCSEMap() { SelectionDAGCSEMap::SelectionDAGCSEMap() : NumNodes(0) {
NumBuckets = 256; NumBuckets = 256;
Buckets = new void*[NumBuckets]; Buckets = new void*[NumBuckets];
memset(Buckets, 0, NumBuckets*sizeof(void*)); memset(Buckets, 0, NumBuckets*sizeof(void*));
@@ -211,6 +224,8 @@ SDNode *SelectionDAGCSEMap::FindNodeOrInsertPos(const NodeID &ID,
/// is not already in the map. InsertPos must be obtained from /// is not already in the map. InsertPos must be obtained from
/// FindNodeOrInsertPos. /// FindNodeOrInsertPos.
void SelectionDAGCSEMap::InsertNode(SDNode *N, void *InsertPos) { void SelectionDAGCSEMap::InsertNode(SDNode *N, void *InsertPos) {
++NumNodes;
/// The insert position is actually a bucket pointer. /// The insert position is actually a bucket pointer.
void **Bucket = static_cast<void**>(InsertPos); void **Bucket = static_cast<void**>(InsertPos);
@@ -230,12 +245,15 @@ void SelectionDAGCSEMap::InsertNode(SDNode *N, void *InsertPos) {
/// RemoveNode - Remove a node from the CSE map, returning true if one was /// RemoveNode - Remove a node from the CSE map, returning true if one was
/// removed or false if the node was not in the CSE map. /// removed or false if the node was not in the CSE map.
bool SelectionDAGCSEMap::RemoveNode(SDNode *N) { bool SelectionDAGCSEMap::RemoveNode(SDNode *N) {
// Because each bucket is a circular list, we don't need to compute N's hash // Because each bucket is a circular list, we don't need to compute N's hash
// to remove it. Chase around the list until we find the node (or bucket) // to remove it. Chase around the list until we find the node (or bucket)
// which points to N. // which points to N.
void *Ptr = N->getNextInBucket(); void *Ptr = N->getNextInBucket();
if (Ptr == 0) return false; // Not in CSEMap. if (Ptr == 0) return false; // Not in CSEMap.
--NumNodes;
void *NodeNextPtr = Ptr; void *NodeNextPtr = Ptr;
N->SetNextInBucket(0); N->SetNextInBucket(0);
while (1) { while (1) {