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