1//===- llvm/Transforms/Utils/BypassSlowDivision.h --------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains an optimization for div and rem on architectures that
11// execute short instructions significantly faster than longer instructions.
12// For example, on Intel Atom 32-bit divides are slow enough that during
13// runtime it is profitable to check the value of the operands, and if they are
14// positive and less than 256 use an unsigned 8-bit divide.
15//
16//===----------------------------------------------------------------------===//
17
18#ifndef LLVM_TRANSFORMS_UTILS_BYPASSSLOWDIVISION_H
19#define LLVM_TRANSFORMS_UTILS_BYPASSSLOWDIVISION_H
20
21#include "llvm/ADT/DenseMap.h"
22#include "llvm/IR/Function.h"
23
24namespace llvm {
25
26/// This optimization identifies DIV instructions that can be
27/// profitably bypassed and carried out with a shorter, faster divide.
28bool bypassSlowDivision(Function &F,
29                        Function::iterator &I,
30                        const DenseMap<unsigned int, unsigned int> &BypassWidth);
31
32} // End llvm namespace
33
34#endif
35