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//===- HexagonTargetTransformInfo.cpp - Hexagon specific TTI pass ---------===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
/// \file
/// This file implements a TargetTransformInfo analysis pass specific to the
/// Hexagon target machine. It uses the target's detailed information to provide
/// more precise answers to certain TTI queries, while letting the target
/// independent and default TTI implementations handle the rest.
#include "HexagonTargetTransformInfo.h"
#include "HexagonSubtarget.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/User.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
#define DEBUG_TYPE "hexagontti"
static cl::opt<bool> EmitLookupTables("hexagon-emit-lookup-tables",
cl::init(true), cl::Hidden,
cl::desc("Control lookup table emission on Hexagon target"));
HexagonTTIImpl::getPopcntSupport(unsigned IntTyWidthInBit) const {
// Return Fast Hardware support as every input < 64 bits will be promoted
// to 64 bits.
return TargetTransformInfo::PSK_FastHardware;
// The Hexagon target can unroll loops with run-time trip counts.
void HexagonTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
TTI::UnrollingPreferences &UP) {
UP.Runtime = UP.Partial = true;
unsigned HexagonTTIImpl::getNumberOfRegisters(bool vector) const {
return vector ? 0 : 32;
unsigned HexagonTTIImpl::getPrefetchDistance() const {
return getST()->getL1PrefetchDistance();
unsigned HexagonTTIImpl::getCacheLineSize() const {
return getST()->getL1CacheLineSize();
int HexagonTTIImpl::getUserCost(const User *U,
ArrayRef<const Value *> Operands) {
auto isCastFoldedIntoLoad = [](const CastInst *CI) -> bool {
if (!CI->isIntegerCast())
return false;
const LoadInst *LI = dyn_cast<const LoadInst>(CI->getOperand(0));
// Technically, this code could allow multiple uses of the load, and
// check if all the uses are the same extension operation, but this
// should be sufficient for most cases.
if (!LI || !LI->hasOneUse())
return false;
// Only extensions from an integer type shorter than 32-bit to i32
// can be folded into the load.
unsigned SBW = CI->getSrcTy()->getIntegerBitWidth();
unsigned DBW = CI->getDestTy()->getIntegerBitWidth();
return DBW == 32 && (SBW < DBW);
if (const CastInst *CI = dyn_cast<const CastInst>(U))
if (isCastFoldedIntoLoad(CI))
return TargetTransformInfo::TCC_Free;
return BaseT::getUserCost(U, Operands);
bool HexagonTTIImpl::shouldBuildLookupTables() const {
return EmitLookupTables;