mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-24 19:52:54 +01:00
89 lines
2.8 KiB
C++
89 lines
2.8 KiB
C++
//===-- llvm/ADT/IntEqClasses.h - Equiv. Classes of Integers ----*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Equivalence classes for small integers. This is a mapping of the integers
|
|
// 0 .. N-1 into M equivalence classes numbered 0 .. M-1.
|
|
//
|
|
// Initially each integer has its own equivalence class. Classes are joined by
|
|
// passing a representative member of each class to join().
|
|
//
|
|
// Once the classes are built, compress() will number them 0 .. M-1 and prevent
|
|
// further changes.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_ADT_INTEQCLASSES_H
|
|
#define LLVM_ADT_INTEQCLASSES_H
|
|
|
|
#include "llvm/ADT/SmallVector.h"
|
|
|
|
namespace llvm {
|
|
|
|
class IntEqClasses {
|
|
/// EC - When uncompressed, map each integer to a smaller member of its
|
|
/// equivalence class. The class leader is the smallest member and maps to
|
|
/// itself.
|
|
///
|
|
/// When compressed, EC[i] is the equivalence class of i.
|
|
SmallVector<unsigned, 8> EC;
|
|
|
|
/// NumClasses - The number of equivalence classes when compressed, or 0 when
|
|
/// uncompressed.
|
|
unsigned NumClasses;
|
|
|
|
public:
|
|
/// IntEqClasses - Create an equivalence class mapping for 0 .. N-1.
|
|
IntEqClasses(unsigned N = 0) : NumClasses(0) { grow(N); }
|
|
|
|
/// grow - Increase capacity to hold 0 .. N-1, putting new integers in unique
|
|
/// equivalence classes.
|
|
/// This requires an uncompressed map.
|
|
void grow(unsigned N);
|
|
|
|
/// clear - Clear all classes so that grow() will assign a unique class to
|
|
/// every integer.
|
|
void clear() {
|
|
EC.clear();
|
|
NumClasses = 0;
|
|
}
|
|
|
|
/// join - Join the equivalence classes of a and b. After joining classes,
|
|
/// findLeader(a) == findLeader(b).
|
|
/// This requires an uncompressed map.
|
|
void join(unsigned a, unsigned b);
|
|
|
|
/// findLeader - Compute the leader of a's equivalence class. This is the
|
|
/// smallest member of the class.
|
|
/// This requires an uncompressed map.
|
|
unsigned findLeader(unsigned a) const;
|
|
|
|
/// compress - Compress equivalence classes by numbering them 0 .. M.
|
|
/// This makes the equivalence class map immutable.
|
|
void compress();
|
|
|
|
/// getNumClasses - Return the number of equivalence classes after compress()
|
|
/// was called.
|
|
unsigned getNumClasses() const { return NumClasses; }
|
|
|
|
/// operator[] - Return a's equivalence class number, 0 .. getNumClasses()-1.
|
|
/// This requires a compressed map.
|
|
unsigned operator[](unsigned a) const {
|
|
assert(NumClasses && "operator[] called before compress()");
|
|
return EC[a];
|
|
}
|
|
|
|
/// uncompress - Change back to the uncompressed representation that allows
|
|
/// editing.
|
|
void uncompress();
|
|
};
|
|
|
|
} // End llvm namespace
|
|
|
|
#endif
|