mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-23 11:13:28 +01:00
ae65e281f3
to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
77 lines
2.2 KiB
C++
77 lines
2.2 KiB
C++
//===-- llvm/ADT/IntEqClasses.cpp - Equivalence Classes of Integers -------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// 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.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/ADT/IntEqClasses.h"
|
|
|
|
using namespace llvm;
|
|
|
|
void IntEqClasses::grow(unsigned N) {
|
|
assert(NumClasses == 0 && "grow() called after compress().");
|
|
EC.reserve(N);
|
|
while (EC.size() < N)
|
|
EC.push_back(EC.size());
|
|
}
|
|
|
|
unsigned IntEqClasses::join(unsigned a, unsigned b) {
|
|
assert(NumClasses == 0 && "join() called after compress().");
|
|
unsigned eca = EC[a];
|
|
unsigned ecb = EC[b];
|
|
// Update pointers while searching for the leaders, compressing the paths
|
|
// incrementally. The larger leader will eventually be updated, joining the
|
|
// classes.
|
|
while (eca != ecb)
|
|
if (eca < ecb) {
|
|
EC[b] = eca;
|
|
b = ecb;
|
|
ecb = EC[b];
|
|
} else {
|
|
EC[a] = ecb;
|
|
a = eca;
|
|
eca = EC[a];
|
|
}
|
|
|
|
return eca;
|
|
}
|
|
|
|
unsigned IntEqClasses::findLeader(unsigned a) const {
|
|
assert(NumClasses == 0 && "findLeader() called after compress().");
|
|
while (a != EC[a])
|
|
a = EC[a];
|
|
return a;
|
|
}
|
|
|
|
void IntEqClasses::compress() {
|
|
if (NumClasses)
|
|
return;
|
|
for (unsigned i = 0, e = EC.size(); i != e; ++i)
|
|
EC[i] = (EC[i] == i) ? NumClasses++ : EC[EC[i]];
|
|
}
|
|
|
|
void IntEqClasses::uncompress() {
|
|
if (!NumClasses)
|
|
return;
|
|
SmallVector<unsigned, 8> Leader;
|
|
for (unsigned i = 0, e = EC.size(); i != e; ++i)
|
|
if (EC[i] < Leader.size())
|
|
EC[i] = Leader[EC[i]];
|
|
else
|
|
Leader.push_back(EC[i] = i);
|
|
NumClasses = 0;
|
|
}
|