mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-10-19 19:12:56 +02:00
68245049cd
This reverts commit r299287 plus clean-ups. The localizer pass is a helper pass that could be run at O0 in the GISel pipeline to work around the deficiency of the fast register allocator. It basically shortens the live-ranges of the constants so that the allocator does not spill all over the place. Long term fix would be to make the greedy allocator fast. llvm-svn: 304051
79 lines
2.9 KiB
C++
79 lines
2.9 KiB
C++
//== llvm/CodeGen/GlobalISel/Localizer.h - Localizer -------------*- 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 describes the interface of the Localizer pass.
|
|
/// This pass moves/duplicates constant-like instructions close to their uses.
|
|
/// Its primarily goal is to workaround the deficiencies of the fast register
|
|
/// allocator.
|
|
/// With GlobalISel constants are all materialized in the entry block of
|
|
/// a function. However, the fast allocator cannot rematerialize constants and
|
|
/// has a lot more live-ranges to deal with and will most likely end up
|
|
/// spilling a lot.
|
|
/// By pushing the constants close to their use, we only create small
|
|
/// live-ranges.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CODEGEN_GLOBALISEL_LOCALIZER_H
|
|
#define LLVM_CODEGEN_GLOBALISEL_LOCALIZER_H
|
|
|
|
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
|
|
#include "llvm/CodeGen/MachineFunctionPass.h"
|
|
|
|
namespace llvm {
|
|
// Forward declarations.
|
|
class MachineRegisterInfo;
|
|
|
|
/// This pass implements the localization mechanism described at the
|
|
/// top of this file. One specificity of the implementation is that
|
|
/// it will materialize one and only one instance of a constant per
|
|
/// basic block, thus enabling reuse of that constant within that block.
|
|
/// Moreover, it only materializes constants in blocks where they
|
|
/// are used. PHI uses are considered happening at the end of the
|
|
/// related predecessor.
|
|
class Localizer : public MachineFunctionPass {
|
|
public:
|
|
static char ID;
|
|
|
|
private:
|
|
/// MRI contains all the register class/bank information that this
|
|
/// pass uses and updates.
|
|
MachineRegisterInfo *MRI;
|
|
|
|
/// Check whether or not \p MI needs to be moved close to its uses.
|
|
static bool shouldLocalize(const MachineInstr &MI);
|
|
|
|
/// Check if \p MOUse is used in the same basic block as \p Def.
|
|
/// If the use is in the same block, we say it is local.
|
|
/// When the use is not local, \p InsertMBB will contain the basic
|
|
/// block when to insert \p Def to have a local use.
|
|
static bool isLocalUse(MachineOperand &MOUse, const MachineInstr &Def,
|
|
MachineBasicBlock *&InsertMBB);
|
|
|
|
/// Initialize the field members using \p MF.
|
|
void init(MachineFunction &MF);
|
|
|
|
public:
|
|
Localizer();
|
|
|
|
StringRef getPassName() const override { return "Localizer"; }
|
|
|
|
MachineFunctionProperties getRequiredProperties() const override {
|
|
return MachineFunctionProperties()
|
|
.set(MachineFunctionProperties::Property::IsSSA)
|
|
.set(MachineFunctionProperties::Property::Legalized)
|
|
.set(MachineFunctionProperties::Property::RegBankSelected);
|
|
}
|
|
|
|
bool runOnMachineFunction(MachineFunction &MF) override;
|
|
};
|
|
|
|
} // End namespace llvm.
|
|
|
|
#endif
|