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Simplify PBQP graph removeAdjEdgeId implementation. 

llvm-svn: 204857
This commit is contained in:
Lang Hames 2014-03-26 21:21:53 +00:00
parent c35c4b3ddb
commit 5391ac4759
1 changed files with 10 additions and 12 deletions
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22
llvm/include/llvm/CodeGen/PBQP/Graph.h
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@ -67,16 +67,16 @@ namespace PBQP {
return Idx;
}
// If a swap is performed, returns the new EdgeId that must be
// updated, otherwise returns invalidEdgeId().
EdgeId removeAdjEdgeId(AdjEdgeIdx Idx) {
EdgeId EIdToUpdate = Graph::invalidEdgeId();
if (Idx < AdjEdgeIds.size() - 1) {
std::swap(AdjEdgeIds[Idx], AdjEdgeIds.back());
EIdToUpdate = AdjEdgeIds[Idx];
}
void removeAdjEdgeId(Graph &G, NodeId ThisNId, AdjEdgeIdx Idx) {
// Swap-and-pop for fast removal.
// 1) Update the adj index of the edge currently at back().
// 2) Swap Edge at Idx with back().
// 3) pop_back()
// If Idx == size() - 1 then the updateAdjEdgeIdx and swap are
// redundant, but both operations are cheap.
G.getEdge(AdjEdgeIds.back()).updateAdjEdgeIdx(ThisNId, Idx);
std::swap(AdjEdgeIds[Idx], AdjEdgeIds.back());
AdjEdgeIds.pop_back();
return EIdToUpdate;
}
const AdjEdgeList& getAdjEdgeIds() const { return AdjEdgeIds; }
@ -138,9 +138,7 @@ namespace PBQP {
assert(ThisEdgeAdjIdxs[NIdx] != NodeEntry::getInvalidAdjEdgeIdx() &&
"Edge not connected to NIds[NIdx].");
NodeEntry &N = G.getNode(NIds[NIdx]);
EdgeId EIdToUpdate = N.removeAdjEdgeId(ThisEdgeAdjIdxs[NIdx]);
if (EIdToUpdate != Graph::invalidEdgeId())
G.getEdge(EIdToUpdate).updateAdjEdgeIdx(NIds[NIdx], ThisEdgeAdjIdxs[NIdx]);
N.removeAdjEdgeId(G, NIds[NIdx], ThisEdgeAdjIdxs[NIdx]);
ThisEdgeAdjIdxs[NIdx] = NodeEntry::getInvalidAdjEdgeIdx();
}