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llvm-mirror/lib/Target/MSP430/MSP430Subtarget.cpp
Craig Topper 10839866a1 [X86][MC][Target] Initial backend support a tune CPU to support -mtune
This patch implements initial backend support for a -mtune CPU controlled by a "tune-cpu" function attribute. If the attribute is not present X86 will use the resolved CPU from target-cpu attribute or command line.

This patch adds MC layer support a tune CPU. Each CPU now has two sets of features stored in their GenSubtargetInfo.inc tables . These features lists are passed separately to the Processor and ProcessorModel classes in tablegen. The tune list defaults to an empty list to avoid changes to non-X86. This annoyingly increases the size of static tables on all target as we now store 24 more bytes per CPU. I haven't quantified the overall impact, but I can if we're concerned.

One new test is added to X86 to show a few tuning features with mismatched tune-cpu and target-cpu/target-feature attributes to demonstrate independent control. Another new test is added to demonstrate that the scheduler model follows the tune CPU.

I have not added a -mtune to llc/opt or MC layer command line yet. With no attributes we'll just use the -mcpu for both. MC layer tools will always follow the normal CPU for tuning.

Differential Revision: https://reviews.llvm.org/D85165
2020-08-14 15:31:50 -07:00

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//===-- MSP430Subtarget.cpp - MSP430 Subtarget Information ----------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements the MSP430 specific subclass of TargetSubtargetInfo.
//
//===----------------------------------------------------------------------===//
#include "MSP430Subtarget.h"
#include "MSP430.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
#define DEBUG_TYPE "msp430-subtarget"
static cl::opt<MSP430Subtarget::HWMultEnum>
HWMultModeOption("mhwmult", cl::Hidden,
cl::desc("Hardware multiplier use mode for MSP430"),
cl::init(MSP430Subtarget::NoHWMult),
cl::values(
clEnumValN(MSP430Subtarget::NoHWMult, "none",
"Do not use hardware multiplier"),
clEnumValN(MSP430Subtarget::HWMult16, "16bit",
"Use 16-bit hardware multiplier"),
clEnumValN(MSP430Subtarget::HWMult32, "32bit",
"Use 32-bit hardware multiplier"),
clEnumValN(MSP430Subtarget::HWMultF5, "f5series",
"Use F5 series hardware multiplier")));
#define GET_SUBTARGETINFO_TARGET_DESC
#define GET_SUBTARGETINFO_CTOR
#include "MSP430GenSubtargetInfo.inc"
void MSP430Subtarget::anchor() { }
MSP430Subtarget &
MSP430Subtarget::initializeSubtargetDependencies(StringRef CPU, StringRef FS) {
ExtendedInsts = false;
HWMultMode = NoHWMult;
StringRef CPUName = CPU;
if (CPUName.empty())
CPUName = "msp430";
ParseSubtargetFeatures(CPUName, /*TuneCPU*/ CPUName, FS);
if (HWMultModeOption != NoHWMult)
HWMultMode = HWMultModeOption;
return *this;
}
MSP430Subtarget::MSP430Subtarget(const Triple &TT, const std::string &CPU,
const std::string &FS, const TargetMachine &TM)
: MSP430GenSubtargetInfo(TT, CPU, /*TuneCPU*/ CPU, FS), FrameLowering(),
InstrInfo(initializeSubtargetDependencies(CPU, FS)), TLInfo(TM, *this) {}