llvm-project/llvm/lib/Target/PowerPC/PPCPreEmitPeephole.cpp

96 lines
3.1 KiB
C++

//===--------- PPCPreEmitPeephole.cpp - Late peephole optimizations -------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// A pre-emit peephole for catching opportunities introduced by late passes such
// as MachineBlockPlacement.
//
//===----------------------------------------------------------------------===//
#include "PPC.h"
#include "PPCInstrInfo.h"
#include "PPCSubtarget.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/LivePhysRegs.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
#define DEBUG_TYPE "ppc-pre-emit-peephole"
STATISTIC(NumRRConvertedInPreEmit,
"Number of r+r instructions converted to r+i in pre-emit peephole");
STATISTIC(NumRemovedInPreEmit,
"Number of instructions deleted in pre-emit peephole");
static cl::opt<bool>
RunPreEmitPeephole("ppc-late-peephole", cl::Hidden, cl::init(true),
cl::desc("Run pre-emit peephole optimizations."));
namespace {
class PPCPreEmitPeephole : public MachineFunctionPass {
public:
static char ID;
PPCPreEmitPeephole() : MachineFunctionPass(ID) {
initializePPCPreEmitPeepholePass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
MachineFunctionPass::getAnalysisUsage(AU);
}
MachineFunctionProperties getRequiredProperties() const override {
return MachineFunctionProperties().set(
MachineFunctionProperties::Property::NoVRegs);
}
bool runOnMachineFunction(MachineFunction &MF) override {
if (skipFunction(MF.getFunction()) || !RunPreEmitPeephole)
return false;
bool Changed = false;
const PPCInstrInfo *TII = MF.getSubtarget<PPCSubtarget>().getInstrInfo();
SmallVector<MachineInstr *, 4> InstrsToErase;
for (MachineBasicBlock &MBB : MF) {
for (MachineInstr &MI : MBB) {
MachineInstr *DefMIToErase = nullptr;
if (TII->convertToImmediateForm(MI, &DefMIToErase)) {
Changed = true;
NumRRConvertedInPreEmit++;
LLVM_DEBUG(dbgs() << "Converted instruction to imm form: ");
LLVM_DEBUG(MI.dump());
if (DefMIToErase) {
InstrsToErase.push_back(DefMIToErase);
}
}
}
}
for (MachineInstr *MI : InstrsToErase) {
LLVM_DEBUG(dbgs() << "PPC pre-emit peephole: erasing instruction: ");
LLVM_DEBUG(MI->dump());
MI->eraseFromParent();
NumRemovedInPreEmit++;
}
return Changed;
}
};
}
INITIALIZE_PASS(PPCPreEmitPeephole, DEBUG_TYPE, "PowerPC Pre-Emit Peephole",
false, false)
char PPCPreEmitPeephole::ID = 0;
FunctionPass *llvm::createPPCPreEmitPeepholePass() {
return new PPCPreEmitPeephole();
}