MipsPreLegalizerCombiner.cpp
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//=== lib/CodeGen/GlobalISel/MipsPreLegalizerCombiner.cpp --------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This pass does combining of machine instructions at the generic MI level,
// before the legalizer.
//
//===----------------------------------------------------------------------===//
#include "MipsTargetMachine.h"
#include "llvm/CodeGen/GlobalISel/Combiner.h"
#include "llvm/CodeGen/GlobalISel/CombinerHelper.h"
#include "llvm/CodeGen/GlobalISel/CombinerInfo.h"
#include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/InitializePasses.h"
#define DEBUG_TYPE "mips-prelegalizer-combiner"
using namespace llvm;
namespace {
class MipsPreLegalizerCombinerInfo : public CombinerInfo {
public:
MipsPreLegalizerCombinerInfo()
: CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
/*LegalizerInfo*/ nullptr, /*EnableOpt*/ false,
/*EnableOptSize*/ false, /*EnableMinSize*/ false) {}
virtual bool combine(GISelChangeObserver &Observer, MachineInstr &MI,
MachineIRBuilder &B) const override;
};
bool MipsPreLegalizerCombinerInfo::combine(GISelChangeObserver &Observer,
MachineInstr &MI,
MachineIRBuilder &B) const {
CombinerHelper Helper(Observer, B);
switch (MI.getOpcode()) {
default:
return false;
case TargetOpcode::G_LOAD:
case TargetOpcode::G_SEXTLOAD:
case TargetOpcode::G_ZEXTLOAD: {
// Don't attempt to combine non power of 2 loads or unaligned loads when
// subtarget doesn't support them.
auto MMO = *MI.memoperands_begin();
const MipsSubtarget &STI =
static_cast<const MipsSubtarget &>(MI.getMF()->getSubtarget());
if (!isPowerOf2_64(MMO->getSize()))
return false;
bool isUnaligned = MMO->getAlign() < MMO->getSize();
if (!STI.systemSupportsUnalignedAccess() && isUnaligned)
return false;
return Helper.tryCombineExtendingLoads(MI);
}
}
return false;
}
// Pass boilerplate
// ================
class MipsPreLegalizerCombiner : public MachineFunctionPass {
public:
static char ID;
MipsPreLegalizerCombiner();
StringRef getPassName() const override { return "MipsPreLegalizerCombiner"; }
bool runOnMachineFunction(MachineFunction &MF) override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
};
} // end anonymous namespace
void MipsPreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<TargetPassConfig>();
AU.setPreservesCFG();
getSelectionDAGFallbackAnalysisUsage(AU);
MachineFunctionPass::getAnalysisUsage(AU);
}
MipsPreLegalizerCombiner::MipsPreLegalizerCombiner() : MachineFunctionPass(ID) {
initializeMipsPreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
}
bool MipsPreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
if (MF.getProperties().hasProperty(
MachineFunctionProperties::Property::FailedISel))
return false;
auto *TPC = &getAnalysis<TargetPassConfig>();
MipsPreLegalizerCombinerInfo PCInfo;
Combiner C(PCInfo, TPC);
return C.combineMachineInstrs(MF, nullptr);
}
char MipsPreLegalizerCombiner::ID = 0;
INITIALIZE_PASS_BEGIN(MipsPreLegalizerCombiner, DEBUG_TYPE,
"Combine Mips machine instrs before legalization", false,
false)
INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
INITIALIZE_PASS_END(MipsPreLegalizerCombiner, DEBUG_TYPE,
"Combine Mips machine instrs before legalization", false,
false)
namespace llvm {
FunctionPass *createMipsPreLegalizeCombiner() {
return new MipsPreLegalizerCombiner();
}
} // end namespace llvm