llvm/lib/CodeGen/GlobalISel/Utils.cpp
Aditya Nandakumar 4925efae1f [GISEL]: Move getConstantVReg to Utils
NFCI

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@300751 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-19 20:48:50 +00:00

113 lines
4.1 KiB
C++

//===- llvm/CodeGen/GlobalISel/Utils.cpp -------------------------*- C++ -*-==//
//
// 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 the utility functions used by the GlobalISel
/// pipeline.
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/GlobalISel/Utils.h"
#include "llvm/ADT/Twine.h"
#include "llvm/CodeGen/GlobalISel/RegisterBankInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/IR/Constants.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetRegisterInfo.h"
#define DEBUG_TYPE "globalisel-utils"
using namespace llvm;
unsigned llvm::constrainOperandRegClass(
const MachineFunction &MF, const TargetRegisterInfo &TRI,
MachineRegisterInfo &MRI, const TargetInstrInfo &TII,
const RegisterBankInfo &RBI, MachineInstr &InsertPt, const MCInstrDesc &II,
unsigned Reg, unsigned OpIdx) {
// Assume physical registers are properly constrained.
assert(TargetRegisterInfo::isVirtualRegister(Reg) &&
"PhysReg not implemented");
const TargetRegisterClass *RegClass = TII.getRegClass(II, OpIdx, &TRI, MF);
if (!RBI.constrainGenericRegister(Reg, *RegClass, MRI)) {
unsigned NewReg = MRI.createVirtualRegister(RegClass);
BuildMI(*InsertPt.getParent(), InsertPt, InsertPt.getDebugLoc(),
TII.get(TargetOpcode::COPY), NewReg)
.addReg(Reg);
return NewReg;
}
return Reg;
}
bool llvm::isTriviallyDead(const MachineInstr &MI,
const MachineRegisterInfo &MRI) {
// If we can move an instruction, we can remove it. Otherwise, it has
// a side-effect of some sort.
bool SawStore = false;
if (!MI.isSafeToMove(/*AA=*/nullptr, SawStore))
return false;
// Instructions without side-effects are dead iff they only define dead vregs.
for (auto &MO : MI.operands()) {
if (!MO.isReg() || !MO.isDef())
continue;
unsigned Reg = MO.getReg();
if (TargetRegisterInfo::isPhysicalRegister(Reg) ||
!MRI.use_nodbg_empty(Reg))
return false;
}
return true;
}
void llvm::reportGISelFailure(MachineFunction &MF, const TargetPassConfig &TPC,
MachineOptimizationRemarkEmitter &MORE,
MachineOptimizationRemarkMissed &R) {
MF.getProperties().set(MachineFunctionProperties::Property::FailedISel);
// Print the function name explicitly if we don't have a debug location (which
// makes the diagnostic less useful) or if we're going to emit a raw error.
if (!R.getLocation().isValid() || TPC.isGlobalISelAbortEnabled())
R << (" (in function: " + MF.getName() + ")").str();
if (TPC.isGlobalISelAbortEnabled())
report_fatal_error(R.getMsg());
else
MORE.emit(R);
}
void llvm::reportGISelFailure(MachineFunction &MF, const TargetPassConfig &TPC,
MachineOptimizationRemarkEmitter &MORE,
const char *PassName, StringRef Msg,
const MachineInstr &MI) {
MachineOptimizationRemarkMissed R(PassName, "GISelFailure: ",
MI.getDebugLoc(), MI.getParent());
R << Msg << ": " << ore::MNV("Inst", MI);
reportGISelFailure(MF, TPC, MORE, R);
}
Optional<int64_t> llvm::getConstantVRegVal(unsigned VReg,
const MachineRegisterInfo &MRI) {
MachineInstr *MI = MRI.getVRegDef(VReg);
if (MI->getOpcode() != TargetOpcode::G_CONSTANT)
return None;
if (MI->getOperand(1).isImm())
return MI->getOperand(1).getImm();
if (MI->getOperand(1).isCImm() &&
MI->getOperand(1).getCImm()->getBitWidth() <= 64)
return MI->getOperand(1).getCImm()->getSExtValue();
return None;
}