llvm-6502/include/llvm/CodeGen/EdgeBundles.h
Jakob Stoklund Olesen 1dc12aa148 Give a small negative bias to giant edge bundles.
This helps compile time when the greedy register allocator splits live
ranges in giant functions. Without the bias, we would try to grow
regions through the giant edge bundles, usually to find out that the
region became too big and expensive.

If a live range has many uses in blocks near the giant bundle, the small
negative bias doesn't make a big difference, and we still consider
regions including the giant edge bundle.

Giant edge bundles are usually connected to landing pads or indirect
branches.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157174 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-21 03:11:23 +00:00

70 lines
2.4 KiB
C++

//===-------- EdgeBundles.h - Bundles of CFG edges --------------*- c++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// The EdgeBundles analysis forms equivalence classes of CFG edges such that all
// edges leaving a machine basic block are in the same bundle, and all edges
// leaving a basic block are in the same bundle.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_EDGEBUNDLES_H
#define LLVM_CODEGEN_EDGEBUNDLES_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/IntEqClasses.h"
#include "llvm/ADT/Twine.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
namespace llvm {
class EdgeBundles : public MachineFunctionPass {
const MachineFunction *MF;
/// EC - Each edge bundle is an equivalence class. The keys are:
/// 2*BB->getNumber() -> Ingoing bundle.
/// 2*BB->getNumber()+1 -> Outgoing bundle.
IntEqClasses EC;
/// Blocks - Map each bundle to a list of basic block numbers.
SmallVector<SmallVector<unsigned, 8>, 4> Blocks;
public:
static char ID;
EdgeBundles() : MachineFunctionPass(ID) {}
/// getBundle - Return the ingoing (Out = false) or outgoing (Out = true)
/// bundle number for basic block #N
unsigned getBundle(unsigned N, bool Out) const { return EC[2 * N + Out]; }
/// getNumBundles - Return the total number of bundles in the CFG.
unsigned getNumBundles() const { return EC.getNumClasses(); }
/// getBlocks - Return an array of blocks that are connected to Bundle.
ArrayRef<unsigned> getBlocks(unsigned Bundle) const { return Blocks[Bundle]; }
/// getMachineFunction - Return the last machine function computed.
const MachineFunction *getMachineFunction() const { return MF; }
/// view - Visualize the annotated bipartite CFG with Graphviz.
void view() const;
private:
virtual bool runOnMachineFunction(MachineFunction&);
virtual void getAnalysisUsage(AnalysisUsage&) const;
};
/// Specialize WriteGraph, the standard implementation won't work.
raw_ostream &WriteGraph(raw_ostream &O, const EdgeBundles &G,
bool ShortNames = false,
const Twine &Title = "");
} // end namespace llvm
#endif