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0b8c9a80f2
into their new header subdirectory: include/llvm/IR. This matches the directory structure of lib, and begins to correct a long standing point of file layout clutter in LLVM. There are still more header files to move here, but I wanted to handle them in separate commits to make tracking what files make sense at each layer easier. The only really questionable files here are the target intrinsic tablegen files. But that's a battle I'd rather not fight today. I've updated both CMake and Makefile build systems (I think, and my tests think, but I may have missed something). I've also re-sorted the includes throughout the project. I'll be committing updates to Clang, DragonEgg, and Polly momentarily. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171366 91177308-0d34-0410-b5e6-96231b3b80d8
112 lines
3.5 KiB
C++
112 lines
3.5 KiB
C++
//===- llvm/Analysis/MaximumSpanningTree.h - Interface ----------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This module provides means for calculating a maximum spanning tree for a
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// given set of weighted edges. The type parameter T is the type of a node.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_MAXIMUMSPANNINGTREE_H
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#define LLVM_ANALYSIS_MAXIMUMSPANNINGTREE_H
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#include "llvm/ADT/EquivalenceClasses.h"
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#include "llvm/IR/BasicBlock.h"
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#include <algorithm>
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#include <vector>
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namespace llvm {
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/// MaximumSpanningTree - A MST implementation.
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/// The type parameter T determines the type of the nodes of the graph.
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template <typename T>
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class MaximumSpanningTree {
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public:
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typedef std::pair<const T*, const T*> Edge;
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typedef std::pair<Edge, double> EdgeWeight;
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typedef std::vector<EdgeWeight> EdgeWeights;
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protected:
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typedef std::vector<Edge> MaxSpanTree;
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MaxSpanTree MST;
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private:
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// A comparing class for comparing weighted edges.
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struct EdgeWeightCompare {
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static bool getBlockSize(const T *X) {
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const BasicBlock *BB = dyn_cast_or_null<BasicBlock>(X);
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return BB ? BB->size() : 0;
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}
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bool operator()(EdgeWeight X, EdgeWeight Y) const {
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if (X.second > Y.second) return true;
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if (X.second < Y.second) return false;
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// Equal edge weights: break ties by comparing block sizes.
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size_t XSizeA = getBlockSize(X.first.first);
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size_t YSizeA = getBlockSize(Y.first.first);
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if (XSizeA > YSizeA) return true;
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if (XSizeA < YSizeA) return false;
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size_t XSizeB = getBlockSize(X.first.second);
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size_t YSizeB = getBlockSize(Y.first.second);
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if (XSizeB > YSizeB) return true;
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if (XSizeB < YSizeB) return false;
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return false;
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}
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};
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public:
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static char ID; // Class identification, replacement for typeinfo
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/// MaximumSpanningTree() - Takes a vector of weighted edges and returns a
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/// spanning tree.
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MaximumSpanningTree(EdgeWeights &EdgeVector) {
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std::stable_sort(EdgeVector.begin(), EdgeVector.end(), EdgeWeightCompare());
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// Create spanning tree, Forest contains a special data structure
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// that makes checking if two nodes are already in a common (sub-)tree
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// fast and cheap.
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EquivalenceClasses<const T*> Forest;
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for (typename EdgeWeights::iterator EWi = EdgeVector.begin(),
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EWe = EdgeVector.end(); EWi != EWe; ++EWi) {
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Edge e = (*EWi).first;
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Forest.insert(e.first);
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Forest.insert(e.second);
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}
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// Iterate over the sorted edges, biggest first.
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for (typename EdgeWeights::iterator EWi = EdgeVector.begin(),
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EWe = EdgeVector.end(); EWi != EWe; ++EWi) {
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Edge e = (*EWi).first;
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if (Forest.findLeader(e.first) != Forest.findLeader(e.second)) {
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Forest.unionSets(e.first, e.second);
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// So we know now that the edge is not already in a subtree, so we push
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// the edge to the MST.
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MST.push_back(e);
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}
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}
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}
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typename MaxSpanTree::iterator begin() {
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return MST.begin();
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}
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typename MaxSpanTree::iterator end() {
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return MST.end();
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}
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};
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} // End llvm namespace
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#endif
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