Files
clang-p2996/llvm/lib/CodeGen/GlobalISel/InstructionSelector.cpp
Daniel Sanders ea8711b88e Re-commit r315885: [globalisel][tblgen] Add support for iPTR and implement am_unscaled* and am_indexed*
Summary:
iPTR is a pointer of subtarget-specific size to any address space. Therefore
type checks on this size derive the SizeInBits from a subtarget hook.

At this point, we can import the simplests G_LOAD rules and select load
instructions using them. Further patches will support for the predicates to
enable additional loads as well as the stores.

The previous commit failed on MSVC due to a failure to convert an
initializer_list to a std::vector. Hopefully, MSVC will accept this version.

Depends on D37457

Reviewers: ab, qcolombet, t.p.northover, rovka, aditya_nandakumar

Reviewed By: qcolombet

Subscribers: kristof.beyls, javed.absar, llvm-commits, igorb

Differential Revision: https://reviews.llvm.org/D37458

llvm-svn: 315887
2017-10-16 03:36:29 +00:00

123 lines
4.1 KiB
C++

//===- llvm/CodeGen/GlobalISel/InstructionSelector.cpp --------------------===//
//
// 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 InstructionSelector class.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
#include "llvm/CodeGen/GlobalISel/Utils.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include <cassert>
#define DEBUG_TYPE "instructionselector"
using namespace llvm;
InstructionSelector::MatcherState::MatcherState(unsigned MaxRenderers)
: Renderers(MaxRenderers), MIs() {}
InstructionSelector::InstructionSelector() = default;
bool InstructionSelector::constrainOperandRegToRegClass(
MachineInstr &I, unsigned OpIdx, const TargetRegisterClass &RC,
const TargetInstrInfo &TII, const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) const {
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
MachineRegisterInfo &MRI = MF.getRegInfo();
return
constrainRegToClass(MRI, TII, RBI, I, I.getOperand(OpIdx).getReg(), RC);
}
bool InstructionSelector::constrainSelectedInstRegOperands(
MachineInstr &I, const TargetInstrInfo &TII, const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) const {
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
MachineRegisterInfo &MRI = MF.getRegInfo();
for (unsigned OpI = 0, OpE = I.getNumExplicitOperands(); OpI != OpE; ++OpI) {
MachineOperand &MO = I.getOperand(OpI);
// There's nothing to be done on non-register operands.
if (!MO.isReg())
continue;
DEBUG(dbgs() << "Converting operand: " << MO << '\n');
assert(MO.isReg() && "Unsupported non-reg operand");
unsigned Reg = MO.getReg();
// Physical registers don't need to be constrained.
if (TRI.isPhysicalRegister(Reg))
continue;
// Register operands with a value of 0 (e.g. predicate operands) don't need
// to be constrained.
if (Reg == 0)
continue;
// If the operand is a vreg, we should constrain its regclass, and only
// insert COPYs if that's impossible.
// constrainOperandRegClass does that for us.
MO.setReg(constrainOperandRegClass(MF, TRI, MRI, TII, RBI, I, I.getDesc(),
Reg, OpI));
// Tie uses to defs as indicated in MCInstrDesc if this hasn't already been
// done.
if (MO.isUse()) {
int DefIdx = I.getDesc().getOperandConstraint(OpI, MCOI::TIED_TO);
if (DefIdx != -1 && !I.isRegTiedToUseOperand(DefIdx))
I.tieOperands(DefIdx, OpI);
}
}
return true;
}
bool InstructionSelector::isOperandImmEqual(
const MachineOperand &MO, int64_t Value,
const MachineRegisterInfo &MRI) const {
if (MO.isReg() && MO.getReg())
if (auto VRegVal = getConstantVRegVal(MO.getReg(), MRI))
return *VRegVal == Value;
return false;
}
bool InstructionSelector::isBaseWithConstantOffset(
const MachineOperand &Root, const MachineRegisterInfo &MRI) const {
if (!Root.isReg())
return false;
MachineInstr *RootI = MRI.getVRegDef(Root.getReg());
if (RootI->getOpcode() != TargetOpcode::G_GEP)
return false;
MachineOperand &RHS = RootI->getOperand(2);
MachineInstr *RHSI = MRI.getVRegDef(RHS.getReg());
if (RHSI->getOpcode() != TargetOpcode::G_CONSTANT)
return false;
return true;
}
bool InstructionSelector::isObviouslySafeToFold(MachineInstr &MI) const {
return !MI.mayLoadOrStore() && !MI.hasUnmodeledSideEffects() &&
MI.implicit_operands().begin() == MI.implicit_operands().end();
}