1//===-- WebAssemblyTargetTransformInfo.cpp - WebAssembly-specific TTI -----===//
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/// \file
11/// \brief This file defines the WebAssembly-specific TargetTransformInfo
12/// implementation.
13///
14//===----------------------------------------------------------------------===//
15
16#include "WebAssemblyTargetTransformInfo.h"
17#include "llvm/Support/Debug.h"
18#include "llvm/Target/CostTable.h"
19using namespace llvm;
20
21#define DEBUG_TYPE "wasmtti"
22
23TargetTransformInfo::PopcntSupportKind
24WebAssemblyTTIImpl::getPopcntSupport(unsigned TyWidth) const {
25  assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2");
26  return TargetTransformInfo::PSK_FastHardware;
27}
28
29unsigned WebAssemblyTTIImpl::getNumberOfRegisters(bool Vector) {
30  unsigned Result = BaseT::getNumberOfRegisters(Vector);
31
32  // For SIMD, use at least 16 registers, as a rough guess.
33  if (Vector)
34    Result = std::max(Result, 16u);
35
36  return Result;
37}
38
39unsigned WebAssemblyTTIImpl::getRegisterBitWidth(bool Vector) {
40  if (Vector && getST()->hasSIMD128())
41    return 128;
42
43  return 64;
44}
45
46unsigned WebAssemblyTTIImpl::getArithmeticInstrCost(
47    unsigned Opcode, Type *Ty, TTI::OperandValueKind Opd1Info,
48    TTI::OperandValueKind Opd2Info, TTI::OperandValueProperties Opd1PropInfo,
49    TTI::OperandValueProperties Opd2PropInfo) {
50
51  unsigned Cost = BasicTTIImplBase<WebAssemblyTTIImpl>::getArithmeticInstrCost(
52      Opcode, Ty, Opd1Info, Opd2Info, Opd1PropInfo, Opd2PropInfo);
53
54  if (VectorType *VTy = dyn_cast<VectorType>(Ty)) {
55    switch (Opcode) {
56    case Instruction::LShr:
57    case Instruction::AShr:
58    case Instruction::Shl:
59      // SIMD128's shifts currently only accept a scalar shift count. For each
60      // element, we'll need to extract, op, insert. The following is a rough
61      // approxmation.
62      if (Opd2Info != TTI::OK_UniformValue &&
63          Opd2Info != TTI::OK_UniformConstantValue)
64        Cost = VTy->getNumElements() *
65               (TargetTransformInfo::TCC_Basic +
66                getArithmeticInstrCost(Opcode, VTy->getElementType()) +
67                TargetTransformInfo::TCC_Basic);
68      break;
69    }
70  }
71  return Cost;
72}
73
74unsigned WebAssemblyTTIImpl::getVectorInstrCost(unsigned Opcode, Type *Val,
75                                                unsigned Index) {
76  unsigned Cost = BasicTTIImplBase::getVectorInstrCost(Opcode, Val, Index);
77
78  // SIMD128's insert/extract currently only take constant indices.
79  if (Index == -1u)
80    return Cost + 25 * TargetTransformInfo::TCC_Expensive;
81
82  return Cost;
83}
84