llvm-project/llvm/lib/CodeGen/GlobalISel/InstructionSelector.cpp
Matt Arsenault 581d13f8ae GlobalISel: Return APInt from getConstantVRegVal
Returning int64_t was arbitrarily limiting for wide integer types, and
the functions should handle the full generality of the IR.

Also changes the full form which returns the originally defined
vreg. Add another wrapper for the common case of just immediately
converting to int64_t (arguably this would be useful for the full
return value case as well).

One possible issue with this change is some of the existing uses did
break without conversion to getConstantVRegSExtVal, and it's possible
some without adequate test coverage are now broken.
2020-12-22 22:23:58 -05:00

84 lines
2.9 KiB
C++

//===- llvm/CodeGen/GlobalISel/InstructionSelector.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
//
//===----------------------------------------------------------------------===//
//
/// \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/CodeGen/TargetRegisterInfo.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.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 constrainOperandRegClass(MF, TRI, MRI, TII, RBI, I, RC,
I.getOperand(OpIdx));
}
bool InstructionSelector::isOperandImmEqual(
const MachineOperand &MO, int64_t Value,
const MachineRegisterInfo &MRI) const {
if (MO.isReg() && MO.getReg())
if (auto VRegVal = getConstantVRegValWithLookThrough(MO.getReg(), MRI))
return VRegVal->Value.getSExtValue() == 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_PTR_ADD)
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,
MachineInstr &IntoMI) const {
// Immediate neighbours are already folded.
if (MI.getParent() == IntoMI.getParent() &&
std::next(MI.getIterator()) == IntoMI.getIterator())
return true;
return !MI.mayLoadOrStore() && !MI.mayRaiseFPException() &&
!MI.hasUnmodeledSideEffects() && MI.implicit_operands().empty();
}