1 //===-- TargetLowering.cpp - Implement the TargetLowering class -----------===//
3 // The LLVM Compiler Infrastructure
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.
8 //===----------------------------------------------------------------------===//
10 // This implements the TargetLowering class.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Target/TargetLowering.h"
15 #include "llvm/Target/TargetMachine.h"
16 #include "llvm/CodeGen/SelectionDAG.h"
19 TargetLowering::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));
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;
35 TargetLowering::~TargetLowering() {}
37 /// setValueTypeAction - Set the action for a particular value type. This
38 /// assumes an action has not already been set for this value type.
39 static void SetValueTypeAction(MVT::ValueType VT,
40 TargetLowering::LegalizeAction Action,
42 MVT::ValueType *TransformToType,
43 unsigned &ValueTypeActions) {
44 ValueTypeActions |= Action << (VT*2);
45 if (Action == TargetLowering::Promote) {
46 MVT::ValueType PromoteTo;
50 unsigned LargerReg = VT+1;
51 while (!TLI.isTypeLegal((MVT::ValueType)LargerReg)) {
53 assert(MVT::isInteger((MVT::ValueType)LargerReg) &&
54 "Nothing to promote to??");
56 PromoteTo = (MVT::ValueType)LargerReg;
59 assert(MVT::isInteger(VT) == MVT::isInteger(PromoteTo) &&
60 MVT::isFloatingPoint(VT) == MVT::isFloatingPoint(PromoteTo) &&
61 "Can only promote from int->int or fp->fp!");
62 assert(VT < PromoteTo && "Must promote to a larger type!");
63 TransformToType[VT] = PromoteTo;
64 } else if (Action == TargetLowering::Expand) {
65 assert(MVT::isInteger(VT) && VT > MVT::i8 &&
66 "Cannot expand this type: target must support SOME integer reg!");
67 // Expand to the next smaller integer type!
68 TransformToType[VT] = (MVT::ValueType)(VT-1);
73 /// computeRegisterProperties - Once all of the register classes are added,
74 /// this allows us to compute derived properties we expose.
75 void TargetLowering::computeRegisterProperties() {
76 assert(MVT::LAST_VALUETYPE <= 16 &&
77 "Too many value types for ValueTypeActions to hold!");
79 // Everything defaults to one.
80 for (unsigned i = 0; i != MVT::LAST_VALUETYPE; ++i)
81 NumElementsForVT[i] = 1;
83 // Find the largest integer register class.
84 unsigned LargestIntReg = MVT::i128;
85 for (; RegClassForVT[LargestIntReg] == 0; --LargestIntReg)
86 assert(LargestIntReg != MVT::i1 && "No integer registers defined!");
88 // Every integer value type larger than this largest register takes twice as
89 // many registers to represent as the previous ValueType.
90 unsigned ExpandedReg = LargestIntReg; ++LargestIntReg;
91 for (++ExpandedReg; MVT::isInteger((MVT::ValueType)ExpandedReg);++ExpandedReg)
92 NumElementsForVT[ExpandedReg] = 2*NumElementsForVT[ExpandedReg-1];
94 // Inspect all of the ValueType's possible, deciding how to process them.
95 for (unsigned IntReg = MVT::i1; IntReg <= MVT::i128; ++IntReg)
96 // If we are expanding this type, expand it!
97 if (getNumElements((MVT::ValueType)IntReg) != 1)
98 SetValueTypeAction((MVT::ValueType)IntReg, Expand, *this, TransformToType,
100 else if (!isTypeLegal((MVT::ValueType)IntReg))
101 // Otherwise, if we don't have native support, we must promote to a
103 SetValueTypeAction((MVT::ValueType)IntReg, Promote, *this,
104 TransformToType, ValueTypeActions);
106 TransformToType[(MVT::ValueType)IntReg] = (MVT::ValueType)IntReg;
108 // If the target does not have native support for F32, promote it to F64.
109 if (!isTypeLegal(MVT::f32))
110 SetValueTypeAction(MVT::f32, Promote, *this,
111 TransformToType, ValueTypeActions);
113 TransformToType[MVT::f32] = MVT::f32;
115 assert(isTypeLegal(MVT::f64) && "Target does not support FP?");
116 TransformToType[MVT::f64] = MVT::f64;