From 0b57cec536236d46e3dba9bd041533462f33dbb7 Mon Sep 17 00:00:00 2001 From: Dimitry Andric Date: Fri, 20 Dec 2019 19:53:05 +0000 Subject: Move all sources from the llvm project into contrib/llvm-project. This uses the new layout of the upstream repository, which was recently migrated to GitHub, and converted into a "monorepo". That is, most of the earlier separate sub-projects with their own branches and tags were consolidated into one top-level directory, and are now branched and tagged together. Updating the vendor area to match this layout is next. --- .../llvm-project/llvm/lib/Support/IntEqClasses.cpp | 76 ++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 contrib/llvm-project/llvm/lib/Support/IntEqClasses.cpp (limited to 'contrib/llvm-project/llvm/lib/Support/IntEqClasses.cpp') diff --git a/contrib/llvm-project/llvm/lib/Support/IntEqClasses.cpp b/contrib/llvm-project/llvm/lib/Support/IntEqClasses.cpp new file mode 100644 index 000000000000..4a976dcefc65 --- /dev/null +++ b/contrib/llvm-project/llvm/lib/Support/IntEqClasses.cpp @@ -0,0 +1,76 @@ +//===-- 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 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; +} -- cgit v1.2.3