TargetRecip.h revision f3ef5332fa3f4d5ec72c178a2b19dac363a19383 
1//===--------------------- llvm/Target/TargetRecip.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 class is used to customize machine-specific reciprocal estimate code
11// generation in a target-independent way.
12// If a target does not support operations in this specification, then code
13// generation will default to using supported operations.
14//
15//===----------------------------------------------------------------------===//
16
17#ifndef LLVM_TARGET_TARGETRECIP_H
18#define LLVM_TARGET_TARGETRECIP_H
19
20#include "llvm/ADT/StringRef.h"
21#include <vector>
22#include <string>
23#include <map>
24
25namespace llvm {
26
27struct TargetRecip {
28public:
29  TargetRecip();
30
31  /// Initialize all or part of the operations from command-line options or
32  /// a front end.
33  TargetRecip(const std::vector<std::string> &Args);
34
35  /// Set whether a particular reciprocal operation is enabled and how many
36  /// refinement steps are needed when using it. Use "all" to set enablement
37  /// and refinement steps for all operations.
38  void setDefaults(StringRef Key, bool Enable, unsigned RefSteps);
39
40  /// Return true if the reciprocal operation has been enabled by default or
41  /// from the command-line. Return false if the operation has been disabled
42  /// by default or from the command-line.
43  bool isEnabled(StringRef Key) const;
44
45  /// Return the number of iterations necessary to refine the
46  /// the result of a machine instruction for the given reciprocal operation.
47  unsigned getRefinementSteps(StringRef Key) const;
48
49  bool operator==(const TargetRecip &Other) const;
50
51private:
52  enum {
53    Uninitialized = -1
54  };
55
56  struct RecipParams {
57    int8_t Enabled;
58    int8_t RefinementSteps;
59
60    RecipParams() : Enabled(Uninitialized), RefinementSteps(Uninitialized) {}
61  };
62
63  std::map<StringRef, RecipParams> RecipMap;
64  typedef std::map<StringRef, RecipParams>::iterator RecipIter;
65  typedef std::map<StringRef, RecipParams>::const_iterator ConstRecipIter;
66
67  bool parseGlobalParams(const std::string &Arg);
68  void parseIndividualParams(const std::vector<std::string> &Args);
69};
70
71} // End llvm namespace
72
73#endif
74