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[PBQP] Use a local bit-matrix to speedup searching an edge in the graph.

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Build time (user time) for building llvm+clang+lldb in release mode:
 - default allocator: 9086 seconds
 - with PBQP: 9126 seconds
 - with PBQP + local bit matrix cache: 9097 seconds

llvm-svn: 231360
This commit is contained in:
Arnaud A. de Grandmaison 2015-03-05 09:12:59 +00:00
parent 92d61decb9
commit 2068314641
1 changed files with 10 additions and 3 deletions
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13
lib/CodeGen/RegAllocPBQP.cpp
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@ -181,6 +181,8 @@ private:
typedef std::pair<AllowedRegVecPtr, AllowedRegVecPtr> IKey;
typedef DenseMap<IKey, PBQPRAGraph::MatrixPtr> IMatrixCache;
typedef DenseSet<IKey> DisjointAllowedRegsCache;
typedef std::pair<PBQP::GraphBase::NodeId, PBQP::GraphBase::NodeId> IEdgeKey;
typedef DenseSet<IEdgeKey> IEdgeCache;
bool haveDisjointAllowedRegs(const PBQPRAGraph &G, PBQPRAGraph::NodeId NId,
PBQPRAGraph::NodeId MId,
@ -277,6 +279,10 @@ public:
// and uniquing them.
IMatrixCache C;
// Finding an edge is expensive in the worst case (O(max_clique(G))). So
// cache locally edges we have already seen.
IEdgeCache EC;
// Cache known disjoint allowed registers pairs
DisjointAllowedRegsCache D;
@ -329,14 +335,15 @@ public:
continue;
// Check that we haven't already added this edge
// FIXME: findEdge is expensive in the worst case (O(max_clique(G))).
// It might be better to replace this with a local bit-matrix.
if (G.findEdge(NId, MId) != PBQPRAGraph::invalidEdgeId())
IEdgeKey EK(std::min(NId, MId), std::max(NId, MId));
if (EC.count(EK))
continue;
// This is a new edge - add it to the graph.
if (!createInterferenceEdge(G, NId, MId, C))
setDisjointAllowedRegs(G, NId, MId, D);
else
EC.insert(EK);
}
// Finally, add Cur to the Active set.