TargetLowering.cpp revision 3a03ebb37747c2b3fd9b4f8b44f1124f53727894 
1//===-- TargetLowering.cpp - Implement the TargetLowering class -----------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This implements the TargetLowering class.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Target/TargetLowering.h"
15#include "llvm/Target/TargetMachine.h"
16#include "llvm/CodeGen/SelectionDAG.h"
17using namespace llvm;
18
19TargetLowering::TargetLowering(TargetMachine &tm)
20  : TM(tm), TD(TM.getTargetData()), ValueTypeActions(0) {
21  assert(ISD::BUILTIN_OP_END <= 128 &&
22         "Fixed size array in TargetLowering is not large enough!");
23  // All operations default to being supported.
24  memset(OpActions, 0, sizeof(OpActions));
25
26  IsLittleEndian = TD.isLittleEndian();
27  ShiftAmountTy = SetCCResultTy = PointerTy = getValueType(TD.getIntPtrType());
28  ShiftAmtHandling = Undefined;
29  memset(RegClassForVT, 0,MVT::LAST_VALUETYPE*sizeof(TargetRegisterClass*));
30  maxStoresPerMemSet = maxStoresPerMemCpy = maxStoresPerMemMove = 8;
31  allowUnalignedMemoryAccesses = false;
32  UseUnderscoreSetJmpLongJmp = false;
33  IntDivIsCheap = false;
34  Pow2DivIsCheap = false;
35}
36
37TargetLowering::~TargetLowering() {}
38
39/// setValueTypeAction - Set the action for a particular value type.  This
40/// assumes an action has not already been set for this value type.
41static void SetValueTypeAction(MVT::ValueType VT,
42                               TargetLowering::LegalizeAction Action,
43                               TargetLowering &TLI,
44                               MVT::ValueType *TransformToType,
45                               unsigned long long &ValueTypeActions) {
46  ValueTypeActions |= (unsigned long long)Action << (VT*2);
47  if (Action == TargetLowering::Promote) {
48    MVT::ValueType PromoteTo;
49    if (VT == MVT::f32)
50      PromoteTo = MVT::f64;
51    else {
52      unsigned LargerReg = VT+1;
53      while (!TLI.isTypeLegal((MVT::ValueType)LargerReg)) {
54        ++LargerReg;
55        assert(MVT::isInteger((MVT::ValueType)LargerReg) &&
56               "Nothing to promote to??");
57      }
58      PromoteTo = (MVT::ValueType)LargerReg;
59    }
60
61    assert(MVT::isInteger(VT) == MVT::isInteger(PromoteTo) &&
62           MVT::isFloatingPoint(VT) == MVT::isFloatingPoint(PromoteTo) &&
63           "Can only promote from int->int or fp->fp!");
64    assert(VT < PromoteTo && "Must promote to a larger type!");
65    TransformToType[VT] = PromoteTo;
66  } else if (Action == TargetLowering::Expand) {
67    assert((VT == MVT::Vector || MVT::isInteger(VT)) && VT > MVT::i8 &&
68           "Cannot expand this type: target must support SOME integer reg!");
69    // Expand to the next smaller integer type!
70    TransformToType[VT] = (MVT::ValueType)(VT-1);
71  }
72}
73
74
75/// computeRegisterProperties - Once all of the register classes are added,
76/// this allows us to compute derived properties we expose.
77void TargetLowering::computeRegisterProperties() {
78  assert(MVT::LAST_VALUETYPE <= 32 &&
79         "Too many value types for ValueTypeActions to hold!");
80
81  // Everything defaults to one.
82  for (unsigned i = 0; i != MVT::LAST_VALUETYPE; ++i)
83    NumElementsForVT[i] = 1;
84
85  // Find the largest integer register class.
86  unsigned LargestIntReg = MVT::i128;
87  for (; RegClassForVT[LargestIntReg] == 0; --LargestIntReg)
88    assert(LargestIntReg != MVT::i1 && "No integer registers defined!");
89
90  // Every integer value type larger than this largest register takes twice as
91  // many registers to represent as the previous ValueType.
92  unsigned ExpandedReg = LargestIntReg; ++LargestIntReg;
93  for (++ExpandedReg; MVT::isInteger((MVT::ValueType)ExpandedReg);++ExpandedReg)
94    NumElementsForVT[ExpandedReg] = 2*NumElementsForVT[ExpandedReg-1];
95
96  // Inspect all of the ValueType's possible, deciding how to process them.
97  for (unsigned IntReg = MVT::i1; IntReg <= MVT::i128; ++IntReg)
98    // If we are expanding this type, expand it!
99    if (getNumElements((MVT::ValueType)IntReg) != 1)
100      SetValueTypeAction((MVT::ValueType)IntReg, Expand, *this, TransformToType,
101                         ValueTypeActions);
102    else if (!isTypeLegal((MVT::ValueType)IntReg))
103      // Otherwise, if we don't have native support, we must promote to a
104      // larger type.
105      SetValueTypeAction((MVT::ValueType)IntReg, Promote, *this,
106                         TransformToType, ValueTypeActions);
107    else
108      TransformToType[(MVT::ValueType)IntReg] = (MVT::ValueType)IntReg;
109
110  // If the target does not have native support for F32, promote it to F64.
111  if (!isTypeLegal(MVT::f32))
112    SetValueTypeAction(MVT::f32, Promote, *this,
113                       TransformToType, ValueTypeActions);
114  else
115    TransformToType[MVT::f32] = MVT::f32;
116
117  // Set MVT::Vector to always be Expanded
118  SetValueTypeAction(MVT::Vector, Expand, *this, TransformToType,
119                     ValueTypeActions);
120
121  assert(isTypeLegal(MVT::f64) && "Target does not support FP?");
122  TransformToType[MVT::f64] = MVT::f64;
123}
124
125const char *TargetLowering::getTargetNodeName(unsigned Opcode) const {
126  return NULL;
127}
128
129bool isMaskedValueZeroForTargetNode(const SDOperand &Op,
130                                    uint64_t Mask) const {
131  return false;
132}
133