1 //==-- llvm/CodeGen/SelectionDAGTargetInfo.h - SelectionDAG Info -*- C++ -*-==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the SelectionDAGTargetInfo class, which targets can
11 // subclass to parameterize the SelectionDAG lowering and instruction
14 //===----------------------------------------------------------------------===//
16 #ifndef LLVM_CODEGEN_SELECTIONDAGTARGETINFO_H
17 #define LLVM_CODEGEN_SELECTIONDAGTARGETINFO_H
19 #include "llvm/CodeGen/SelectionDAGNodes.h"
20 #include "llvm/Support/CodeGen.h"
24 //===----------------------------------------------------------------------===//
25 /// Targets can subclass this to parameterize the
26 /// SelectionDAG lowering and instruction selection process.
28 class SelectionDAGTargetInfo {
29 SelectionDAGTargetInfo(const SelectionDAGTargetInfo &) = delete;
30 void operator=(const SelectionDAGTargetInfo &) = delete;
33 explicit SelectionDAGTargetInfo() = default;
34 virtual ~SelectionDAGTargetInfo();
36 /// Emit target-specific code that performs a memcpy.
37 /// This can be used by targets to provide code sequences for cases
38 /// that don't fit the target's parameters for simple loads/stores and can be
39 /// more efficient than using a library call. This function can return a null
40 /// SDValue if the target declines to use custom code and a different
41 /// lowering strategy should be used.
43 /// If AlwaysInline is true, the size is constant and the target should not
44 /// emit any calls and is strongly encouraged to attempt to emit inline code
45 /// even if it is beyond the usual threshold because this intrinsic is being
46 /// expanded in a place where calls are not feasible (e.g. within the prologue
47 /// for another call). If the target chooses to decline an AlwaysInline
48 /// request here, legalize will resort to using simple loads and stores.
49 virtual SDValue EmitTargetCodeForMemcpy(SelectionDAG &DAG, const SDLoc &dl,
50 SDValue Chain, SDValue Op1,
51 SDValue Op2, SDValue Op3,
52 unsigned Align, bool isVolatile,
54 MachinePointerInfo DstPtrInfo,
55 MachinePointerInfo SrcPtrInfo) const {
59 /// Emit target-specific code that performs a memmove.
60 /// This can be used by targets to provide code sequences for cases
61 /// that don't fit the target's parameters for simple loads/stores and can be
62 /// more efficient than using a library call. This function can return a null
63 /// SDValue if the target declines to use custom code and a different
64 /// lowering strategy should be used.
65 virtual SDValue EmitTargetCodeForMemmove(
66 SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Op1,
67 SDValue Op2, SDValue Op3, unsigned Align, bool isVolatile,
68 MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
72 /// Emit target-specific code that performs a memset.
73 /// This can be used by targets to provide code sequences for cases
74 /// that don't fit the target's parameters for simple stores and can be more
75 /// efficient than using a library call. This function can return a null
76 /// SDValue if the target declines to use custom code and a different
77 /// lowering strategy should be used.
78 virtual SDValue EmitTargetCodeForMemset(SelectionDAG &DAG, const SDLoc &dl,
79 SDValue Chain, SDValue Op1,
80 SDValue Op2, SDValue Op3,
81 unsigned Align, bool isVolatile,
82 MachinePointerInfo DstPtrInfo) const {
86 /// Emit target-specific code that performs a memcmp, in cases where that is
87 /// faster than a libcall. The first returned SDValue is the result of the
88 /// memcmp and the second is the chain. Both SDValues can be null if a normal
89 /// libcall should be used.
90 virtual std::pair<SDValue, SDValue>
91 EmitTargetCodeForMemcmp(SelectionDAG &DAG, const SDLoc &dl, SDValue Chain,
92 SDValue Op1, SDValue Op2, SDValue Op3,
93 MachinePointerInfo Op1PtrInfo,
94 MachinePointerInfo Op2PtrInfo) const {
95 return std::make_pair(SDValue(), SDValue());
98 /// Emit target-specific code that performs a memchr, in cases where that is
99 /// faster than a libcall. The first returned SDValue is the result of the
100 /// memchr and the second is the chain. Both SDValues can be null if a normal
101 /// libcall should be used.
102 virtual std::pair<SDValue, SDValue>
103 EmitTargetCodeForMemchr(SelectionDAG &DAG, const SDLoc &dl, SDValue Chain,
104 SDValue Src, SDValue Char, SDValue Length,
105 MachinePointerInfo SrcPtrInfo) const {
106 return std::make_pair(SDValue(), SDValue());
109 /// Emit target-specific code that performs a strcpy or stpcpy, in cases
110 /// where that is faster than a libcall.
111 /// The first returned SDValue is the result of the copy (the start
112 /// of the destination string for strcpy, a pointer to the null terminator
113 /// for stpcpy) and the second is the chain. Both SDValues can be null
114 /// if a normal libcall should be used.
115 virtual std::pair<SDValue, SDValue>
116 EmitTargetCodeForStrcpy(SelectionDAG &DAG, const SDLoc &DL, SDValue Chain,
117 SDValue Dest, SDValue Src,
118 MachinePointerInfo DestPtrInfo,
119 MachinePointerInfo SrcPtrInfo, bool isStpcpy) const {
120 return std::make_pair(SDValue(), SDValue());
123 /// Emit target-specific code that performs a strcmp, in cases where that is
124 /// faster than a libcall.
125 /// The first returned SDValue is the result of the strcmp and the second is
126 /// the chain. Both SDValues can be null if a normal libcall should be used.
127 virtual std::pair<SDValue, SDValue>
128 EmitTargetCodeForStrcmp(SelectionDAG &DAG, const SDLoc &dl, SDValue Chain,
129 SDValue Op1, SDValue Op2,
130 MachinePointerInfo Op1PtrInfo,
131 MachinePointerInfo Op2PtrInfo) const {
132 return std::make_pair(SDValue(), SDValue());
135 virtual std::pair<SDValue, SDValue>
136 EmitTargetCodeForStrlen(SelectionDAG &DAG, const SDLoc &DL, SDValue Chain,
137 SDValue Src, MachinePointerInfo SrcPtrInfo) const {
138 return std::make_pair(SDValue(), SDValue());
141 virtual std::pair<SDValue, SDValue>
142 EmitTargetCodeForStrnlen(SelectionDAG &DAG, const SDLoc &DL, SDValue Chain,
143 SDValue Src, SDValue MaxLength,
144 MachinePointerInfo SrcPtrInfo) const {
145 return std::make_pair(SDValue(), SDValue());
147 // Return true when the decision to generate FMA's (or FMS, FMLA etc) rather
148 // than FMUL and ADD is delegated to the machine combiner.
149 virtual bool generateFMAsInMachineCombiner(CodeGenOpt::Level OptLevel) const {
154 } // end llvm namespace