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//===-- HexagonSplitTFRCondSets.cpp - split TFR condsets into xfers -------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//
//===----------------------------------------------------------------------===//
// This pass tries to provide opportunities for better optimization of muxes.
// The default code generated for something like: flag = (a == b) ? 1 : 3;
// would be:
//
// {p0 = cmp.eq(r0,r1)}
// {r3 = mux(p0,#1,#3)}
//
// This requires two packets. If we use .new predicated immediate transfers,
// then we can do this in a single packet, e.g.:
//
// {p0 = cmp.eq(r0,r1)
// if (p0.new) r3 = #1
// if (!p0.new) r3 = #3}
//
// Note that the conditional assignments are not generated in .new form here.
// We assume opptimisically that they will be formed later.
//
//===----------------------------------------------------------------------===//
#include "Hexagon.h"
#include "HexagonMachineFunctionInfo.h"
#include "HexagonSubtarget.h"
#include "HexagonTargetMachine.h"
#include "llvm/CodeGen/LatencyPriorityQueue.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
#include "llvm/CodeGen/SchedulerRegistry.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
using namespace llvm;
#define DEBUG_TYPE "xfer"
namespace llvm {
void initializeHexagonSplitTFRCondSetsPass(PassRegistry&);
}
namespace {
class HexagonSplitTFRCondSets : public MachineFunctionPass {
public:
static char ID;
HexagonSplitTFRCondSets() : MachineFunctionPass(ID) {
initializeHexagonSplitTFRCondSetsPass(*PassRegistry::getPassRegistry());
}
const char *getPassName() const override {
return "Hexagon Split TFRCondSets";
}
bool runOnMachineFunction(MachineFunction &Fn) override;
};
char HexagonSplitTFRCondSets::ID = 0;
bool HexagonSplitTFRCondSets::runOnMachineFunction(MachineFunction &Fn) {
const TargetInstrInfo *TII = Fn.getSubtarget().getInstrInfo();
// Loop over all of the basic blocks.
for (MachineFunction::iterator MBBb = Fn.begin(), MBBe = Fn.end();
MBBb != MBBe; ++MBBb) {
MachineBasicBlock* MBB = MBBb;
// Traverse the basic block.
for (MachineBasicBlock::iterator MII = MBB->begin(); MII != MBB->end();
++MII) {
MachineInstr *MI = MII;
switch(MI->getOpcode()) {
case Hexagon::TFR_condset_ri: {
int DestReg = MI->getOperand(0).getReg();
int SrcReg1 = MI->getOperand(2).getReg();
// Do not emit the predicated copy if the source and the destination
// is the same register.
if (DestReg != SrcReg1) {
BuildMI(*MBB, MII, MI->getDebugLoc(),
TII->get(Hexagon::A2_tfrt), DestReg).
addReg(MI->getOperand(1).getReg()).addReg(SrcReg1);
}
BuildMI(*MBB, MII, MI->getDebugLoc(),
TII->get(Hexagon::C2_cmoveif), DestReg).
addReg(MI->getOperand(1).getReg()).
addImm(MI->getOperand(3).getImm());
MII = MBB->erase(MI);
--MII;
break;
}
case Hexagon::TFR_condset_ir: {
int DestReg = MI->getOperand(0).getReg();
int SrcReg2 = MI->getOperand(3).getReg();
BuildMI(*MBB, MII, MI->getDebugLoc(),
TII->get(Hexagon::C2_cmoveit), DestReg).
addReg(MI->getOperand(1).getReg()).
addImm(MI->getOperand(2).getImm());
// Do not emit the predicated copy if the source and
// the destination is the same register.
if (DestReg != SrcReg2) {
BuildMI(*MBB, MII, MI->getDebugLoc(),
TII->get(Hexagon::A2_tfrf), DestReg).
addReg(MI->getOperand(1).getReg()).addReg(SrcReg2);
}
MII = MBB->erase(MI);
--MII;
break;
}
case Hexagon::TFR_condset_ii: {
int DestReg = MI->getOperand(0).getReg();
int SrcReg1 = MI->getOperand(1).getReg();
int Immed1 = MI->getOperand(2).getImm();
int Immed2 = MI->getOperand(3).getImm();
BuildMI(*MBB, MII, MI->getDebugLoc(),
TII->get(Hexagon::C2_cmoveit),
DestReg).addReg(SrcReg1).addImm(Immed1);
BuildMI(*MBB, MII, MI->getDebugLoc(),
TII->get(Hexagon::C2_cmoveif),
DestReg).addReg(SrcReg1).addImm(Immed2);
MII = MBB->erase(MI);
--MII;
break;
}
}
}
}
return true;
}
}
//===----------------------------------------------------------------------===//
// Public Constructor Functions
//===----------------------------------------------------------------------===//
static void initializePassOnce(PassRegistry &Registry) {
const char *Name = "Hexagon Split TFRCondSets";
PassInfo *PI = new PassInfo(Name, "hexagon-split-tfr",
&HexagonSplitTFRCondSets::ID, nullptr, false,
false);
Registry.registerPass(*PI, true);
}
void llvm::initializeHexagonSplitTFRCondSetsPass(PassRegistry &Registry) {
CALL_ONCE_INITIALIZATION(initializePassOnce)
}
FunctionPass *llvm::createHexagonSplitTFRCondSets() {
return new HexagonSplitTFRCondSets();
}
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