llvm-project/llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.cpp

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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 "llvm/IR/Instructions.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
#define DEBUG_TYPE "hexagontti"
TargetTransformInfo::PopcntSupportKind
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,
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) {
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);
}