forked from OSchip/llvm-project
1038 lines
36 KiB
C++
1038 lines
36 KiB
C++
//===-- Thumb2SizeReduction.cpp - Thumb2 code size reduction pass -*- C++ -*-=//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "ARM.h"
|
|
#include "ARMBaseInstrInfo.h"
|
|
#include "ARMSubtarget.h"
|
|
#include "MCTargetDesc/ARMAddressingModes.h"
|
|
#include "Thumb2InstrInfo.h"
|
|
#include "llvm/ADT/DenseMap.h"
|
|
#include "llvm/ADT/PostOrderIterator.h"
|
|
#include "llvm/ADT/Statistic.h"
|
|
#include "llvm/CodeGen/MachineFunctionPass.h"
|
|
#include "llvm/CodeGen/MachineInstr.h"
|
|
#include "llvm/CodeGen/MachineInstrBuilder.h"
|
|
#include "llvm/IR/Function.h" // To access Function attributes
|
|
#include "llvm/Support/CommandLine.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
#include "llvm/Target/TargetMachine.h"
|
|
using namespace llvm;
|
|
|
|
#define DEBUG_TYPE "t2-reduce-size"
|
|
|
|
STATISTIC(NumNarrows, "Number of 32-bit instrs reduced to 16-bit ones");
|
|
STATISTIC(Num2Addrs, "Number of 32-bit instrs reduced to 2addr 16-bit ones");
|
|
STATISTIC(NumLdSts, "Number of 32-bit load / store reduced to 16-bit ones");
|
|
|
|
static cl::opt<int> ReduceLimit("t2-reduce-limit",
|
|
cl::init(-1), cl::Hidden);
|
|
static cl::opt<int> ReduceLimit2Addr("t2-reduce-limit2",
|
|
cl::init(-1), cl::Hidden);
|
|
static cl::opt<int> ReduceLimitLdSt("t2-reduce-limit3",
|
|
cl::init(-1), cl::Hidden);
|
|
|
|
namespace {
|
|
/// ReduceTable - A static table with information on mapping from wide
|
|
/// opcodes to narrow
|
|
struct ReduceEntry {
|
|
uint16_t WideOpc; // Wide opcode
|
|
uint16_t NarrowOpc1; // Narrow opcode to transform to
|
|
uint16_t NarrowOpc2; // Narrow opcode when it's two-address
|
|
uint8_t Imm1Limit; // Limit of immediate field (bits)
|
|
uint8_t Imm2Limit; // Limit of immediate field when it's two-address
|
|
unsigned LowRegs1 : 1; // Only possible if low-registers are used
|
|
unsigned LowRegs2 : 1; // Only possible if low-registers are used (2addr)
|
|
unsigned PredCC1 : 2; // 0 - If predicated, cc is on and vice versa.
|
|
// 1 - No cc field.
|
|
// 2 - Always set CPSR.
|
|
unsigned PredCC2 : 2;
|
|
unsigned PartFlag : 1; // 16-bit instruction does partial flag update
|
|
unsigned Special : 1; // Needs to be dealt with specially
|
|
unsigned AvoidMovs: 1; // Avoid movs with shifter operand (for Swift)
|
|
};
|
|
|
|
static const ReduceEntry ReduceTable[] = {
|
|
// Wide, Narrow1, Narrow2, imm1,imm2, lo1, lo2, P/C,PF,S,AM
|
|
{ ARM::t2ADCrr, 0, ARM::tADC, 0, 0, 0, 1, 0,0, 0,0,0 },
|
|
{ ARM::t2ADDri, ARM::tADDi3, ARM::tADDi8, 3, 8, 1, 1, 0,0, 0,1,0 },
|
|
{ ARM::t2ADDrr, ARM::tADDrr, ARM::tADDhirr, 0, 0, 1, 0, 0,1, 0,0,0 },
|
|
{ ARM::t2ADDSri,ARM::tADDi3, ARM::tADDi8, 3, 8, 1, 1, 2,2, 0,1,0 },
|
|
{ ARM::t2ADDSrr,ARM::tADDrr, 0, 0, 0, 1, 0, 2,0, 0,1,0 },
|
|
{ ARM::t2ANDrr, 0, ARM::tAND, 0, 0, 0, 1, 0,0, 1,0,0 },
|
|
{ ARM::t2ASRri, ARM::tASRri, 0, 5, 0, 1, 0, 0,0, 1,0,1 },
|
|
{ ARM::t2ASRrr, 0, ARM::tASRrr, 0, 0, 0, 1, 0,0, 1,0,1 },
|
|
{ ARM::t2BICrr, 0, ARM::tBIC, 0, 0, 0, 1, 0,0, 1,0,0 },
|
|
//FIXME: Disable CMN, as CCodes are backwards from compare expectations
|
|
//{ ARM::t2CMNrr, ARM::tCMN, 0, 0, 0, 1, 0, 2,0, 0,0,0 },
|
|
{ ARM::t2CMNzrr, ARM::tCMNz, 0, 0, 0, 1, 0, 2,0, 0,0,0 },
|
|
{ ARM::t2CMPri, ARM::tCMPi8, 0, 8, 0, 1, 0, 2,0, 0,0,0 },
|
|
{ ARM::t2CMPrr, ARM::tCMPhir, 0, 0, 0, 0, 0, 2,0, 0,1,0 },
|
|
{ ARM::t2EORrr, 0, ARM::tEOR, 0, 0, 0, 1, 0,0, 1,0,0 },
|
|
// FIXME: adr.n immediate offset must be multiple of 4.
|
|
//{ ARM::t2LEApcrelJT,ARM::tLEApcrelJT, 0, 0, 0, 1, 0, 1,0, 0,0,0 },
|
|
{ ARM::t2LSLri, ARM::tLSLri, 0, 5, 0, 1, 0, 0,0, 1,0,1 },
|
|
{ ARM::t2LSLrr, 0, ARM::tLSLrr, 0, 0, 0, 1, 0,0, 1,0,1 },
|
|
{ ARM::t2LSRri, ARM::tLSRri, 0, 5, 0, 1, 0, 0,0, 1,0,1 },
|
|
{ ARM::t2LSRrr, 0, ARM::tLSRrr, 0, 0, 0, 1, 0,0, 1,0,1 },
|
|
{ ARM::t2MOVi, ARM::tMOVi8, 0, 8, 0, 1, 0, 0,0, 1,0,0 },
|
|
{ ARM::t2MOVi16,ARM::tMOVi8, 0, 8, 0, 1, 0, 0,0, 1,1,0 },
|
|
// FIXME: Do we need the 16-bit 'S' variant?
|
|
{ ARM::t2MOVr,ARM::tMOVr, 0, 0, 0, 0, 0, 1,0, 0,0,0 },
|
|
{ ARM::t2MUL, 0, ARM::tMUL, 0, 0, 0, 1, 0,0, 1,0,0 },
|
|
{ ARM::t2MVNr, ARM::tMVN, 0, 0, 0, 1, 0, 0,0, 0,0,0 },
|
|
{ ARM::t2ORRrr, 0, ARM::tORR, 0, 0, 0, 1, 0,0, 1,0,0 },
|
|
{ ARM::t2REV, ARM::tREV, 0, 0, 0, 1, 0, 1,0, 0,0,0 },
|
|
{ ARM::t2REV16, ARM::tREV16, 0, 0, 0, 1, 0, 1,0, 0,0,0 },
|
|
{ ARM::t2REVSH, ARM::tREVSH, 0, 0, 0, 1, 0, 1,0, 0,0,0 },
|
|
{ ARM::t2RORrr, 0, ARM::tROR, 0, 0, 0, 1, 0,0, 1,0,0 },
|
|
{ ARM::t2RSBri, ARM::tRSB, 0, 0, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2RSBSri,ARM::tRSB, 0, 0, 0, 1, 0, 2,0, 0,1,0 },
|
|
{ ARM::t2SBCrr, 0, ARM::tSBC, 0, 0, 0, 1, 0,0, 0,0,0 },
|
|
{ ARM::t2SUBri, ARM::tSUBi3, ARM::tSUBi8, 3, 8, 1, 1, 0,0, 0,0,0 },
|
|
{ ARM::t2SUBrr, ARM::tSUBrr, 0, 0, 0, 1, 0, 0,0, 0,0,0 },
|
|
{ ARM::t2SUBSri,ARM::tSUBi3, ARM::tSUBi8, 3, 8, 1, 1, 2,2, 0,0,0 },
|
|
{ ARM::t2SUBSrr,ARM::tSUBrr, 0, 0, 0, 1, 0, 2,0, 0,0,0 },
|
|
{ ARM::t2SXTB, ARM::tSXTB, 0, 0, 0, 1, 0, 1,0, 0,1,0 },
|
|
{ ARM::t2SXTH, ARM::tSXTH, 0, 0, 0, 1, 0, 1,0, 0,1,0 },
|
|
{ ARM::t2TSTrr, ARM::tTST, 0, 0, 0, 1, 0, 2,0, 0,0,0 },
|
|
{ ARM::t2UXTB, ARM::tUXTB, 0, 0, 0, 1, 0, 1,0, 0,1,0 },
|
|
{ ARM::t2UXTH, ARM::tUXTH, 0, 0, 0, 1, 0, 1,0, 0,1,0 },
|
|
|
|
// FIXME: Clean this up after splitting each Thumb load / store opcode
|
|
// into multiple ones.
|
|
{ ARM::t2LDRi12,ARM::tLDRi, ARM::tLDRspi, 5, 8, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2LDRs, ARM::tLDRr, 0, 0, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2LDRBi12,ARM::tLDRBi, 0, 5, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2LDRBs, ARM::tLDRBr, 0, 0, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2LDRHi12,ARM::tLDRHi, 0, 5, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2LDRHs, ARM::tLDRHr, 0, 0, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2LDRSBs,ARM::tLDRSB, 0, 0, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2LDRSHs,ARM::tLDRSH, 0, 0, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2STRi12,ARM::tSTRi, ARM::tSTRspi, 5, 8, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2STRs, ARM::tSTRr, 0, 0, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2STRBi12,ARM::tSTRBi, 0, 5, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2STRBs, ARM::tSTRBr, 0, 0, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2STRHi12,ARM::tSTRHi, 0, 5, 0, 1, 0, 0,0, 0,1,0 },
|
|
{ ARM::t2STRHs, ARM::tSTRHr, 0, 0, 0, 1, 0, 0,0, 0,1,0 },
|
|
|
|
{ ARM::t2LDMIA, ARM::tLDMIA, 0, 0, 0, 1, 1, 1,1, 0,1,0 },
|
|
{ ARM::t2LDMIA_RET,0, ARM::tPOP_RET, 0, 0, 1, 1, 1,1, 0,1,0 },
|
|
{ ARM::t2LDMIA_UPD,ARM::tLDMIA_UPD,ARM::tPOP,0, 0, 1, 1, 1,1, 0,1,0 },
|
|
// ARM::t2STM (with no basereg writeback) has no Thumb1 equivalent
|
|
{ ARM::t2STMIA_UPD,ARM::tSTMIA_UPD, 0, 0, 0, 1, 1, 1,1, 0,1,0 },
|
|
{ ARM::t2STMDB_UPD, 0, ARM::tPUSH, 0, 0, 1, 1, 1,1, 0,1,0 }
|
|
};
|
|
|
|
class Thumb2SizeReduce : public MachineFunctionPass {
|
|
public:
|
|
static char ID;
|
|
Thumb2SizeReduce(std::function<bool(const Function &)> Ftor);
|
|
|
|
const Thumb2InstrInfo *TII;
|
|
const ARMSubtarget *STI;
|
|
|
|
bool runOnMachineFunction(MachineFunction &MF) override;
|
|
|
|
const char *getPassName() const override {
|
|
return "Thumb2 instruction size reduction pass";
|
|
}
|
|
|
|
private:
|
|
/// ReduceOpcodeMap - Maps wide opcode to index of entry in ReduceTable.
|
|
DenseMap<unsigned, unsigned> ReduceOpcodeMap;
|
|
|
|
bool canAddPseudoFlagDep(MachineInstr *Use, bool IsSelfLoop);
|
|
|
|
bool VerifyPredAndCC(MachineInstr *MI, const ReduceEntry &Entry,
|
|
bool is2Addr, ARMCC::CondCodes Pred,
|
|
bool LiveCPSR, bool &HasCC, bool &CCDead);
|
|
|
|
bool ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI,
|
|
const ReduceEntry &Entry);
|
|
|
|
bool ReduceSpecial(MachineBasicBlock &MBB, MachineInstr *MI,
|
|
const ReduceEntry &Entry, bool LiveCPSR, bool IsSelfLoop);
|
|
|
|
/// ReduceTo2Addr - Reduce a 32-bit instruction to a 16-bit two-address
|
|
/// instruction.
|
|
bool ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI,
|
|
const ReduceEntry &Entry, bool LiveCPSR,
|
|
bool IsSelfLoop);
|
|
|
|
/// ReduceToNarrow - Reduce a 32-bit instruction to a 16-bit
|
|
/// non-two-address instruction.
|
|
bool ReduceToNarrow(MachineBasicBlock &MBB, MachineInstr *MI,
|
|
const ReduceEntry &Entry, bool LiveCPSR,
|
|
bool IsSelfLoop);
|
|
|
|
/// ReduceMI - Attempt to reduce MI, return true on success.
|
|
bool ReduceMI(MachineBasicBlock &MBB, MachineInstr *MI,
|
|
bool LiveCPSR, bool IsSelfLoop);
|
|
|
|
/// ReduceMBB - Reduce width of instructions in the specified basic block.
|
|
bool ReduceMBB(MachineBasicBlock &MBB);
|
|
|
|
bool OptimizeSize;
|
|
bool MinimizeSize;
|
|
|
|
// Last instruction to define CPSR in the current block.
|
|
MachineInstr *CPSRDef;
|
|
// Was CPSR last defined by a high latency instruction?
|
|
// When CPSRDef is null, this refers to CPSR defs in predecessors.
|
|
bool HighLatencyCPSR;
|
|
|
|
struct MBBInfo {
|
|
// The flags leaving this block have high latency.
|
|
bool HighLatencyCPSR;
|
|
// Has this block been visited yet?
|
|
bool Visited;
|
|
|
|
MBBInfo() : HighLatencyCPSR(false), Visited(false) {}
|
|
};
|
|
|
|
SmallVector<MBBInfo, 8> BlockInfo;
|
|
|
|
std::function<bool(const Function &)> PredicateFtor;
|
|
};
|
|
char Thumb2SizeReduce::ID = 0;
|
|
}
|
|
|
|
Thumb2SizeReduce::Thumb2SizeReduce(std::function<bool(const Function &)> Ftor)
|
|
: MachineFunctionPass(ID), PredicateFtor(Ftor) {
|
|
OptimizeSize = MinimizeSize = false;
|
|
for (unsigned i = 0, e = array_lengthof(ReduceTable); i != e; ++i) {
|
|
unsigned FromOpc = ReduceTable[i].WideOpc;
|
|
if (!ReduceOpcodeMap.insert(std::make_pair(FromOpc, i)).second)
|
|
assert(false && "Duplicated entries?");
|
|
}
|
|
}
|
|
|
|
static bool HasImplicitCPSRDef(const MCInstrDesc &MCID) {
|
|
for (const uint16_t *Regs = MCID.getImplicitDefs(); *Regs; ++Regs)
|
|
if (*Regs == ARM::CPSR)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
// Check for a likely high-latency flag def.
|
|
static bool isHighLatencyCPSR(MachineInstr *Def) {
|
|
switch(Def->getOpcode()) {
|
|
case ARM::FMSTAT:
|
|
case ARM::tMUL:
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// canAddPseudoFlagDep - For A9 (and other out-of-order) implementations,
|
|
/// the 's' 16-bit instruction partially update CPSR. Abort the
|
|
/// transformation to avoid adding false dependency on last CPSR setting
|
|
/// instruction which hurts the ability for out-of-order execution engine
|
|
/// to do register renaming magic.
|
|
/// This function checks if there is a read-of-write dependency between the
|
|
/// last instruction that defines the CPSR and the current instruction. If there
|
|
/// is, then there is no harm done since the instruction cannot be retired
|
|
/// before the CPSR setting instruction anyway.
|
|
/// Note, we are not doing full dependency analysis here for the sake of compile
|
|
/// time. We're not looking for cases like:
|
|
/// r0 = muls ...
|
|
/// r1 = add.w r0, ...
|
|
/// ...
|
|
/// = mul.w r1
|
|
/// In this case it would have been ok to narrow the mul.w to muls since there
|
|
/// are indirect RAW dependency between the muls and the mul.w
|
|
bool
|
|
Thumb2SizeReduce::canAddPseudoFlagDep(MachineInstr *Use, bool FirstInSelfLoop) {
|
|
// Disable the check for -Oz (aka OptimizeForSizeHarder).
|
|
if (MinimizeSize || !STI->avoidCPSRPartialUpdate())
|
|
return false;
|
|
|
|
if (!CPSRDef)
|
|
// If this BB loops back to itself, conservatively avoid narrowing the
|
|
// first instruction that does partial flag update.
|
|
return HighLatencyCPSR || FirstInSelfLoop;
|
|
|
|
SmallSet<unsigned, 2> Defs;
|
|
for (const MachineOperand &MO : CPSRDef->operands()) {
|
|
if (!MO.isReg() || MO.isUndef() || MO.isUse())
|
|
continue;
|
|
unsigned Reg = MO.getReg();
|
|
if (Reg == 0 || Reg == ARM::CPSR)
|
|
continue;
|
|
Defs.insert(Reg);
|
|
}
|
|
|
|
for (const MachineOperand &MO : Use->operands()) {
|
|
if (!MO.isReg() || MO.isUndef() || MO.isDef())
|
|
continue;
|
|
unsigned Reg = MO.getReg();
|
|
if (Defs.count(Reg))
|
|
return false;
|
|
}
|
|
|
|
// If the current CPSR has high latency, try to avoid the false dependency.
|
|
if (HighLatencyCPSR)
|
|
return true;
|
|
|
|
// tMOVi8 usually doesn't start long dependency chains, and there are a lot
|
|
// of them, so always shrink them when CPSR doesn't have high latency.
|
|
if (Use->getOpcode() == ARM::t2MOVi ||
|
|
Use->getOpcode() == ARM::t2MOVi16)
|
|
return false;
|
|
|
|
// No read-after-write dependency. The narrowing will add false dependency.
|
|
return true;
|
|
}
|
|
|
|
bool
|
|
Thumb2SizeReduce::VerifyPredAndCC(MachineInstr *MI, const ReduceEntry &Entry,
|
|
bool is2Addr, ARMCC::CondCodes Pred,
|
|
bool LiveCPSR, bool &HasCC, bool &CCDead) {
|
|
if ((is2Addr && Entry.PredCC2 == 0) ||
|
|
(!is2Addr && Entry.PredCC1 == 0)) {
|
|
if (Pred == ARMCC::AL) {
|
|
// Not predicated, must set CPSR.
|
|
if (!HasCC) {
|
|
// Original instruction was not setting CPSR, but CPSR is not
|
|
// currently live anyway. It's ok to set it. The CPSR def is
|
|
// dead though.
|
|
if (!LiveCPSR) {
|
|
HasCC = true;
|
|
CCDead = true;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
} else {
|
|
// Predicated, must not set CPSR.
|
|
if (HasCC)
|
|
return false;
|
|
}
|
|
} else if ((is2Addr && Entry.PredCC2 == 2) ||
|
|
(!is2Addr && Entry.PredCC1 == 2)) {
|
|
/// Old opcode has an optional def of CPSR.
|
|
if (HasCC)
|
|
return true;
|
|
// If old opcode does not implicitly define CPSR, then it's not ok since
|
|
// these new opcodes' CPSR def is not meant to be thrown away. e.g. CMP.
|
|
if (!HasImplicitCPSRDef(MI->getDesc()))
|
|
return false;
|
|
HasCC = true;
|
|
} else {
|
|
// 16-bit instruction does not set CPSR.
|
|
if (HasCC)
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool VerifyLowRegs(MachineInstr *MI) {
|
|
unsigned Opc = MI->getOpcode();
|
|
bool isPCOk = (Opc == ARM::t2LDMIA_RET || Opc == ARM::t2LDMIA_UPD);
|
|
bool isLROk = (Opc == ARM::t2STMDB_UPD);
|
|
bool isSPOk = isPCOk || isLROk;
|
|
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
|
|
const MachineOperand &MO = MI->getOperand(i);
|
|
if (!MO.isReg() || MO.isImplicit())
|
|
continue;
|
|
unsigned Reg = MO.getReg();
|
|
if (Reg == 0 || Reg == ARM::CPSR)
|
|
continue;
|
|
if (isPCOk && Reg == ARM::PC)
|
|
continue;
|
|
if (isLROk && Reg == ARM::LR)
|
|
continue;
|
|
if (Reg == ARM::SP) {
|
|
if (isSPOk)
|
|
continue;
|
|
if (i == 1 && (Opc == ARM::t2LDRi12 || Opc == ARM::t2STRi12))
|
|
// Special case for these ldr / str with sp as base register.
|
|
continue;
|
|
}
|
|
if (!isARMLowRegister(Reg))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
bool
|
|
Thumb2SizeReduce::ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI,
|
|
const ReduceEntry &Entry) {
|
|
if (ReduceLimitLdSt != -1 && ((int)NumLdSts >= ReduceLimitLdSt))
|
|
return false;
|
|
|
|
unsigned Scale = 1;
|
|
bool HasImmOffset = false;
|
|
bool HasShift = false;
|
|
bool HasOffReg = true;
|
|
bool isLdStMul = false;
|
|
unsigned Opc = Entry.NarrowOpc1;
|
|
unsigned OpNum = 3; // First 'rest' of operands.
|
|
uint8_t ImmLimit = Entry.Imm1Limit;
|
|
|
|
switch (Entry.WideOpc) {
|
|
default:
|
|
llvm_unreachable("Unexpected Thumb2 load / store opcode!");
|
|
case ARM::t2LDRi12:
|
|
case ARM::t2STRi12:
|
|
if (MI->getOperand(1).getReg() == ARM::SP) {
|
|
Opc = Entry.NarrowOpc2;
|
|
ImmLimit = Entry.Imm2Limit;
|
|
}
|
|
|
|
Scale = 4;
|
|
HasImmOffset = true;
|
|
HasOffReg = false;
|
|
break;
|
|
case ARM::t2LDRBi12:
|
|
case ARM::t2STRBi12:
|
|
HasImmOffset = true;
|
|
HasOffReg = false;
|
|
break;
|
|
case ARM::t2LDRHi12:
|
|
case ARM::t2STRHi12:
|
|
Scale = 2;
|
|
HasImmOffset = true;
|
|
HasOffReg = false;
|
|
break;
|
|
case ARM::t2LDRs:
|
|
case ARM::t2LDRBs:
|
|
case ARM::t2LDRHs:
|
|
case ARM::t2LDRSBs:
|
|
case ARM::t2LDRSHs:
|
|
case ARM::t2STRs:
|
|
case ARM::t2STRBs:
|
|
case ARM::t2STRHs:
|
|
HasShift = true;
|
|
OpNum = 4;
|
|
break;
|
|
case ARM::t2LDMIA: {
|
|
unsigned BaseReg = MI->getOperand(0).getReg();
|
|
assert(isARMLowRegister(BaseReg));
|
|
|
|
// For the non-writeback version (this one), the base register must be
|
|
// one of the registers being loaded.
|
|
bool isOK = false;
|
|
for (unsigned i = 3; i < MI->getNumOperands(); ++i) {
|
|
if (MI->getOperand(i).getReg() == BaseReg) {
|
|
isOK = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!isOK)
|
|
return false;
|
|
|
|
OpNum = 0;
|
|
isLdStMul = true;
|
|
break;
|
|
}
|
|
case ARM::t2LDMIA_RET: {
|
|
unsigned BaseReg = MI->getOperand(1).getReg();
|
|
if (BaseReg != ARM::SP)
|
|
return false;
|
|
Opc = Entry.NarrowOpc2; // tPOP_RET
|
|
OpNum = 2;
|
|
isLdStMul = true;
|
|
break;
|
|
}
|
|
case ARM::t2LDMIA_UPD:
|
|
case ARM::t2STMIA_UPD:
|
|
case ARM::t2STMDB_UPD: {
|
|
OpNum = 0;
|
|
|
|
unsigned BaseReg = MI->getOperand(1).getReg();
|
|
if (BaseReg == ARM::SP &&
|
|
(Entry.WideOpc == ARM::t2LDMIA_UPD ||
|
|
Entry.WideOpc == ARM::t2STMDB_UPD)) {
|
|
Opc = Entry.NarrowOpc2; // tPOP or tPUSH
|
|
OpNum = 2;
|
|
} else if (!isARMLowRegister(BaseReg) ||
|
|
(Entry.WideOpc != ARM::t2LDMIA_UPD &&
|
|
Entry.WideOpc != ARM::t2STMIA_UPD)) {
|
|
return false;
|
|
}
|
|
|
|
isLdStMul = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
unsigned OffsetReg = 0;
|
|
bool OffsetKill = false;
|
|
bool OffsetInternal = false;
|
|
if (HasShift) {
|
|
OffsetReg = MI->getOperand(2).getReg();
|
|
OffsetKill = MI->getOperand(2).isKill();
|
|
OffsetInternal = MI->getOperand(2).isInternalRead();
|
|
|
|
if (MI->getOperand(3).getImm())
|
|
// Thumb1 addressing mode doesn't support shift.
|
|
return false;
|
|
}
|
|
|
|
unsigned OffsetImm = 0;
|
|
if (HasImmOffset) {
|
|
OffsetImm = MI->getOperand(2).getImm();
|
|
unsigned MaxOffset = ((1 << ImmLimit) - 1) * Scale;
|
|
|
|
if ((OffsetImm & (Scale - 1)) || OffsetImm > MaxOffset)
|
|
// Make sure the immediate field fits.
|
|
return false;
|
|
}
|
|
|
|
// Add the 16-bit load / store instruction.
|
|
DebugLoc dl = MI->getDebugLoc();
|
|
MachineInstrBuilder MIB = BuildMI(MBB, MI, dl, TII->get(Opc));
|
|
if (!isLdStMul) {
|
|
MIB.addOperand(MI->getOperand(0));
|
|
MIB.addOperand(MI->getOperand(1));
|
|
|
|
if (HasImmOffset)
|
|
MIB.addImm(OffsetImm / Scale);
|
|
|
|
assert((!HasShift || OffsetReg) && "Invalid so_reg load / store address!");
|
|
|
|
if (HasOffReg)
|
|
MIB.addReg(OffsetReg, getKillRegState(OffsetKill) |
|
|
getInternalReadRegState(OffsetInternal));
|
|
}
|
|
|
|
// Transfer the rest of operands.
|
|
for (unsigned e = MI->getNumOperands(); OpNum != e; ++OpNum)
|
|
MIB.addOperand(MI->getOperand(OpNum));
|
|
|
|
// Transfer memoperands.
|
|
MIB->setMemRefs(MI->memoperands_begin(), MI->memoperands_end());
|
|
|
|
// Transfer MI flags.
|
|
MIB.setMIFlags(MI->getFlags());
|
|
|
|
DEBUG(errs() << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB);
|
|
|
|
MBB.erase_instr(MI);
|
|
++NumLdSts;
|
|
return true;
|
|
}
|
|
|
|
bool
|
|
Thumb2SizeReduce::ReduceSpecial(MachineBasicBlock &MBB, MachineInstr *MI,
|
|
const ReduceEntry &Entry,
|
|
bool LiveCPSR, bool IsSelfLoop) {
|
|
unsigned Opc = MI->getOpcode();
|
|
if (Opc == ARM::t2ADDri) {
|
|
// If the source register is SP, try to reduce to tADDrSPi, otherwise
|
|
// it's a normal reduce.
|
|
if (MI->getOperand(1).getReg() != ARM::SP) {
|
|
if (ReduceTo2Addr(MBB, MI, Entry, LiveCPSR, IsSelfLoop))
|
|
return true;
|
|
return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop);
|
|
}
|
|
// Try to reduce to tADDrSPi.
|
|
unsigned Imm = MI->getOperand(2).getImm();
|
|
// The immediate must be in range, the destination register must be a low
|
|
// reg, the predicate must be "always" and the condition flags must not
|
|
// be being set.
|
|
if (Imm & 3 || Imm > 1020)
|
|
return false;
|
|
if (!isARMLowRegister(MI->getOperand(0).getReg()))
|
|
return false;
|
|
if (MI->getOperand(3).getImm() != ARMCC::AL)
|
|
return false;
|
|
const MCInstrDesc &MCID = MI->getDesc();
|
|
if (MCID.hasOptionalDef() &&
|
|
MI->getOperand(MCID.getNumOperands()-1).getReg() == ARM::CPSR)
|
|
return false;
|
|
|
|
MachineInstrBuilder MIB = BuildMI(MBB, MI, MI->getDebugLoc(),
|
|
TII->get(ARM::tADDrSPi))
|
|
.addOperand(MI->getOperand(0))
|
|
.addOperand(MI->getOperand(1))
|
|
.addImm(Imm / 4); // The tADDrSPi has an implied scale by four.
|
|
AddDefaultPred(MIB);
|
|
|
|
// Transfer MI flags.
|
|
MIB.setMIFlags(MI->getFlags());
|
|
|
|
DEBUG(errs() << "Converted 32-bit: " << *MI << " to 16-bit: " <<*MIB);
|
|
|
|
MBB.erase_instr(MI);
|
|
++NumNarrows;
|
|
return true;
|
|
}
|
|
|
|
if (Entry.LowRegs1 && !VerifyLowRegs(MI))
|
|
return false;
|
|
|
|
if (MI->mayLoadOrStore())
|
|
return ReduceLoadStore(MBB, MI, Entry);
|
|
|
|
switch (Opc) {
|
|
default: break;
|
|
case ARM::t2ADDSri:
|
|
case ARM::t2ADDSrr: {
|
|
unsigned PredReg = 0;
|
|
if (getInstrPredicate(MI, PredReg) == ARMCC::AL) {
|
|
switch (Opc) {
|
|
default: break;
|
|
case ARM::t2ADDSri: {
|
|
if (ReduceTo2Addr(MBB, MI, Entry, LiveCPSR, IsSelfLoop))
|
|
return true;
|
|
// fallthrough
|
|
}
|
|
case ARM::t2ADDSrr:
|
|
return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
case ARM::t2RSBri:
|
|
case ARM::t2RSBSri:
|
|
case ARM::t2SXTB:
|
|
case ARM::t2SXTH:
|
|
case ARM::t2UXTB:
|
|
case ARM::t2UXTH:
|
|
if (MI->getOperand(2).getImm() == 0)
|
|
return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop);
|
|
break;
|
|
case ARM::t2MOVi16:
|
|
// Can convert only 'pure' immediate operands, not immediates obtained as
|
|
// globals' addresses.
|
|
if (MI->getOperand(1).isImm())
|
|
return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop);
|
|
break;
|
|
case ARM::t2CMPrr: {
|
|
// Try to reduce to the lo-reg only version first. Why there are two
|
|
// versions of the instruction is a mystery.
|
|
// It would be nice to just have two entries in the master table that
|
|
// are prioritized, but the table assumes a unique entry for each
|
|
// source insn opcode. So for now, we hack a local entry record to use.
|
|
static const ReduceEntry NarrowEntry =
|
|
{ ARM::t2CMPrr,ARM::tCMPr, 0, 0, 0, 1, 1,2, 0, 0,1,0 };
|
|
if (ReduceToNarrow(MBB, MI, NarrowEntry, LiveCPSR, IsSelfLoop))
|
|
return true;
|
|
return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop);
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool
|
|
Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI,
|
|
const ReduceEntry &Entry,
|
|
bool LiveCPSR, bool IsSelfLoop) {
|
|
|
|
if (ReduceLimit2Addr != -1 && ((int)Num2Addrs >= ReduceLimit2Addr))
|
|
return false;
|
|
|
|
if (!MinimizeSize && !OptimizeSize && Entry.AvoidMovs &&
|
|
STI->avoidMOVsShifterOperand())
|
|
// Don't issue movs with shifter operand for some CPUs unless we
|
|
// are optimizing / minimizing for size.
|
|
return false;
|
|
|
|
unsigned Reg0 = MI->getOperand(0).getReg();
|
|
unsigned Reg1 = MI->getOperand(1).getReg();
|
|
// t2MUL is "special". The tied source operand is second, not first.
|
|
if (MI->getOpcode() == ARM::t2MUL) {
|
|
unsigned Reg2 = MI->getOperand(2).getReg();
|
|
// Early exit if the regs aren't all low regs.
|
|
if (!isARMLowRegister(Reg0) || !isARMLowRegister(Reg1)
|
|
|| !isARMLowRegister(Reg2))
|
|
return false;
|
|
if (Reg0 != Reg2) {
|
|
// If the other operand also isn't the same as the destination, we
|
|
// can't reduce.
|
|
if (Reg1 != Reg0)
|
|
return false;
|
|
// Try to commute the operands to make it a 2-address instruction.
|
|
MachineInstr *CommutedMI = TII->commuteInstruction(MI);
|
|
if (!CommutedMI)
|
|
return false;
|
|
}
|
|
} else if (Reg0 != Reg1) {
|
|
// Try to commute the operands to make it a 2-address instruction.
|
|
unsigned CommOpIdx1, CommOpIdx2;
|
|
if (!TII->findCommutedOpIndices(MI, CommOpIdx1, CommOpIdx2) ||
|
|
CommOpIdx1 != 1 || MI->getOperand(CommOpIdx2).getReg() != Reg0)
|
|
return false;
|
|
MachineInstr *CommutedMI = TII->commuteInstruction(MI);
|
|
if (!CommutedMI)
|
|
return false;
|
|
}
|
|
if (Entry.LowRegs2 && !isARMLowRegister(Reg0))
|
|
return false;
|
|
if (Entry.Imm2Limit) {
|
|
unsigned Imm = MI->getOperand(2).getImm();
|
|
unsigned Limit = (1 << Entry.Imm2Limit) - 1;
|
|
if (Imm > Limit)
|
|
return false;
|
|
} else {
|
|
unsigned Reg2 = MI->getOperand(2).getReg();
|
|
if (Entry.LowRegs2 && !isARMLowRegister(Reg2))
|
|
return false;
|
|
}
|
|
|
|
// Check if it's possible / necessary to transfer the predicate.
|
|
const MCInstrDesc &NewMCID = TII->get(Entry.NarrowOpc2);
|
|
unsigned PredReg = 0;
|
|
ARMCC::CondCodes Pred = getInstrPredicate(MI, PredReg);
|
|
bool SkipPred = false;
|
|
if (Pred != ARMCC::AL) {
|
|
if (!NewMCID.isPredicable())
|
|
// Can't transfer predicate, fail.
|
|
return false;
|
|
} else {
|
|
SkipPred = !NewMCID.isPredicable();
|
|
}
|
|
|
|
bool HasCC = false;
|
|
bool CCDead = false;
|
|
const MCInstrDesc &MCID = MI->getDesc();
|
|
if (MCID.hasOptionalDef()) {
|
|
unsigned NumOps = MCID.getNumOperands();
|
|
HasCC = (MI->getOperand(NumOps-1).getReg() == ARM::CPSR);
|
|
if (HasCC && MI->getOperand(NumOps-1).isDead())
|
|
CCDead = true;
|
|
}
|
|
if (!VerifyPredAndCC(MI, Entry, true, Pred, LiveCPSR, HasCC, CCDead))
|
|
return false;
|
|
|
|
// Avoid adding a false dependency on partial flag update by some 16-bit
|
|
// instructions which has the 's' bit set.
|
|
if (Entry.PartFlag && NewMCID.hasOptionalDef() && HasCC &&
|
|
canAddPseudoFlagDep(MI, IsSelfLoop))
|
|
return false;
|
|
|
|
// Add the 16-bit instruction.
|
|
DebugLoc dl = MI->getDebugLoc();
|
|
MachineInstrBuilder MIB = BuildMI(MBB, MI, dl, NewMCID);
|
|
MIB.addOperand(MI->getOperand(0));
|
|
if (NewMCID.hasOptionalDef()) {
|
|
if (HasCC)
|
|
AddDefaultT1CC(MIB, CCDead);
|
|
else
|
|
AddNoT1CC(MIB);
|
|
}
|
|
|
|
// Transfer the rest of operands.
|
|
unsigned NumOps = MCID.getNumOperands();
|
|
for (unsigned i = 1, e = MI->getNumOperands(); i != e; ++i) {
|
|
if (i < NumOps && MCID.OpInfo[i].isOptionalDef())
|
|
continue;
|
|
if (SkipPred && MCID.OpInfo[i].isPredicate())
|
|
continue;
|
|
MIB.addOperand(MI->getOperand(i));
|
|
}
|
|
|
|
// Transfer MI flags.
|
|
MIB.setMIFlags(MI->getFlags());
|
|
|
|
DEBUG(errs() << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB);
|
|
|
|
MBB.erase_instr(MI);
|
|
++Num2Addrs;
|
|
return true;
|
|
}
|
|
|
|
bool
|
|
Thumb2SizeReduce::ReduceToNarrow(MachineBasicBlock &MBB, MachineInstr *MI,
|
|
const ReduceEntry &Entry,
|
|
bool LiveCPSR, bool IsSelfLoop) {
|
|
if (ReduceLimit != -1 && ((int)NumNarrows >= ReduceLimit))
|
|
return false;
|
|
|
|
if (!MinimizeSize && !OptimizeSize && Entry.AvoidMovs &&
|
|
STI->avoidMOVsShifterOperand())
|
|
// Don't issue movs with shifter operand for some CPUs unless we
|
|
// are optimizing / minimizing for size.
|
|
return false;
|
|
|
|
unsigned Limit = ~0U;
|
|
if (Entry.Imm1Limit)
|
|
Limit = (1 << Entry.Imm1Limit) - 1;
|
|
|
|
const MCInstrDesc &MCID = MI->getDesc();
|
|
for (unsigned i = 0, e = MCID.getNumOperands(); i != e; ++i) {
|
|
if (MCID.OpInfo[i].isPredicate())
|
|
continue;
|
|
const MachineOperand &MO = MI->getOperand(i);
|
|
if (MO.isReg()) {
|
|
unsigned Reg = MO.getReg();
|
|
if (!Reg || Reg == ARM::CPSR)
|
|
continue;
|
|
if (Entry.LowRegs1 && !isARMLowRegister(Reg))
|
|
return false;
|
|
} else if (MO.isImm() &&
|
|
!MCID.OpInfo[i].isPredicate()) {
|
|
if (((unsigned)MO.getImm()) > Limit)
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// Check if it's possible / necessary to transfer the predicate.
|
|
const MCInstrDesc &NewMCID = TII->get(Entry.NarrowOpc1);
|
|
unsigned PredReg = 0;
|
|
ARMCC::CondCodes Pred = getInstrPredicate(MI, PredReg);
|
|
bool SkipPred = false;
|
|
if (Pred != ARMCC::AL) {
|
|
if (!NewMCID.isPredicable())
|
|
// Can't transfer predicate, fail.
|
|
return false;
|
|
} else {
|
|
SkipPred = !NewMCID.isPredicable();
|
|
}
|
|
|
|
bool HasCC = false;
|
|
bool CCDead = false;
|
|
if (MCID.hasOptionalDef()) {
|
|
unsigned NumOps = MCID.getNumOperands();
|
|
HasCC = (MI->getOperand(NumOps-1).getReg() == ARM::CPSR);
|
|
if (HasCC && MI->getOperand(NumOps-1).isDead())
|
|
CCDead = true;
|
|
}
|
|
if (!VerifyPredAndCC(MI, Entry, false, Pred, LiveCPSR, HasCC, CCDead))
|
|
return false;
|
|
|
|
// Avoid adding a false dependency on partial flag update by some 16-bit
|
|
// instructions which has the 's' bit set.
|
|
if (Entry.PartFlag && NewMCID.hasOptionalDef() && HasCC &&
|
|
canAddPseudoFlagDep(MI, IsSelfLoop))
|
|
return false;
|
|
|
|
// Add the 16-bit instruction.
|
|
DebugLoc dl = MI->getDebugLoc();
|
|
MachineInstrBuilder MIB = BuildMI(MBB, MI, dl, NewMCID);
|
|
MIB.addOperand(MI->getOperand(0));
|
|
if (NewMCID.hasOptionalDef()) {
|
|
if (HasCC)
|
|
AddDefaultT1CC(MIB, CCDead);
|
|
else
|
|
AddNoT1CC(MIB);
|
|
}
|
|
|
|
// Transfer the rest of operands.
|
|
unsigned NumOps = MCID.getNumOperands();
|
|
for (unsigned i = 1, e = MI->getNumOperands(); i != e; ++i) {
|
|
if (i < NumOps && MCID.OpInfo[i].isOptionalDef())
|
|
continue;
|
|
if ((MCID.getOpcode() == ARM::t2RSBSri ||
|
|
MCID.getOpcode() == ARM::t2RSBri ||
|
|
MCID.getOpcode() == ARM::t2SXTB ||
|
|
MCID.getOpcode() == ARM::t2SXTH ||
|
|
MCID.getOpcode() == ARM::t2UXTB ||
|
|
MCID.getOpcode() == ARM::t2UXTH) && i == 2)
|
|
// Skip the zero immediate operand, it's now implicit.
|
|
continue;
|
|
bool isPred = (i < NumOps && MCID.OpInfo[i].isPredicate());
|
|
if (SkipPred && isPred)
|
|
continue;
|
|
const MachineOperand &MO = MI->getOperand(i);
|
|
if (MO.isReg() && MO.isImplicit() && MO.getReg() == ARM::CPSR)
|
|
// Skip implicit def of CPSR. Either it's modeled as an optional
|
|
// def now or it's already an implicit def on the new instruction.
|
|
continue;
|
|
MIB.addOperand(MO);
|
|
}
|
|
if (!MCID.isPredicable() && NewMCID.isPredicable())
|
|
AddDefaultPred(MIB);
|
|
|
|
// Transfer MI flags.
|
|
MIB.setMIFlags(MI->getFlags());
|
|
|
|
DEBUG(errs() << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB);
|
|
|
|
MBB.erase_instr(MI);
|
|
++NumNarrows;
|
|
return true;
|
|
}
|
|
|
|
static bool UpdateCPSRDef(MachineInstr &MI, bool LiveCPSR, bool &DefCPSR) {
|
|
bool HasDef = false;
|
|
for (const MachineOperand &MO : MI.operands()) {
|
|
if (!MO.isReg() || MO.isUndef() || MO.isUse())
|
|
continue;
|
|
if (MO.getReg() != ARM::CPSR)
|
|
continue;
|
|
|
|
DefCPSR = true;
|
|
if (!MO.isDead())
|
|
HasDef = true;
|
|
}
|
|
|
|
return HasDef || LiveCPSR;
|
|
}
|
|
|
|
static bool UpdateCPSRUse(MachineInstr &MI, bool LiveCPSR) {
|
|
for (const MachineOperand &MO : MI.operands()) {
|
|
if (!MO.isReg() || MO.isUndef() || MO.isDef())
|
|
continue;
|
|
if (MO.getReg() != ARM::CPSR)
|
|
continue;
|
|
assert(LiveCPSR && "CPSR liveness tracking is wrong!");
|
|
if (MO.isKill()) {
|
|
LiveCPSR = false;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return LiveCPSR;
|
|
}
|
|
|
|
bool Thumb2SizeReduce::ReduceMI(MachineBasicBlock &MBB, MachineInstr *MI,
|
|
bool LiveCPSR, bool IsSelfLoop) {
|
|
unsigned Opcode = MI->getOpcode();
|
|
DenseMap<unsigned, unsigned>::iterator OPI = ReduceOpcodeMap.find(Opcode);
|
|
if (OPI == ReduceOpcodeMap.end())
|
|
return false;
|
|
const ReduceEntry &Entry = ReduceTable[OPI->second];
|
|
|
|
// Don't attempt normal reductions on "special" cases for now.
|
|
if (Entry.Special)
|
|
return ReduceSpecial(MBB, MI, Entry, LiveCPSR, IsSelfLoop);
|
|
|
|
// Try to transform to a 16-bit two-address instruction.
|
|
if (Entry.NarrowOpc2 &&
|
|
ReduceTo2Addr(MBB, MI, Entry, LiveCPSR, IsSelfLoop))
|
|
return true;
|
|
|
|
// Try to transform to a 16-bit non-two-address instruction.
|
|
if (Entry.NarrowOpc1 &&
|
|
ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) {
|
|
bool Modified = false;
|
|
|
|
// Yes, CPSR could be livein.
|
|
bool LiveCPSR = MBB.isLiveIn(ARM::CPSR);
|
|
MachineInstr *BundleMI = nullptr;
|
|
|
|
CPSRDef = nullptr;
|
|
HighLatencyCPSR = false;
|
|
|
|
// Check predecessors for the latest CPSRDef.
|
|
for (auto *Pred : MBB.predecessors()) {
|
|
const MBBInfo &PInfo = BlockInfo[Pred->getNumber()];
|
|
if (!PInfo.Visited) {
|
|
// Since blocks are visited in RPO, this must be a back-edge.
|
|
continue;
|
|
}
|
|
if (PInfo.HighLatencyCPSR) {
|
|
HighLatencyCPSR = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// If this BB loops back to itself, conservatively avoid narrowing the
|
|
// first instruction that does partial flag update.
|
|
bool IsSelfLoop = MBB.isSuccessor(&MBB);
|
|
MachineBasicBlock::instr_iterator MII = MBB.instr_begin(),E = MBB.instr_end();
|
|
MachineBasicBlock::instr_iterator NextMII;
|
|
for (; MII != E; MII = NextMII) {
|
|
NextMII = std::next(MII);
|
|
|
|
MachineInstr *MI = &*MII;
|
|
if (MI->isBundle()) {
|
|
BundleMI = MI;
|
|
continue;
|
|
}
|
|
if (MI->isDebugValue())
|
|
continue;
|
|
|
|
LiveCPSR = UpdateCPSRUse(*MI, LiveCPSR);
|
|
|
|
// Does NextMII belong to the same bundle as MI?
|
|
bool NextInSameBundle = NextMII != E && NextMII->isBundledWithPred();
|
|
|
|
if (ReduceMI(MBB, MI, LiveCPSR, IsSelfLoop)) {
|
|
Modified = true;
|
|
MachineBasicBlock::instr_iterator I = std::prev(NextMII);
|
|
MI = &*I;
|
|
// Removing and reinserting the first instruction in a bundle will break
|
|
// up the bundle. Fix the bundling if it was broken.
|
|
if (NextInSameBundle && !NextMII->isBundledWithPred())
|
|
NextMII->bundleWithPred();
|
|
}
|
|
|
|
if (!NextInSameBundle && MI->isInsideBundle()) {
|
|
// FIXME: Since post-ra scheduler operates on bundles, the CPSR kill
|
|
// marker is only on the BUNDLE instruction. Process the BUNDLE
|
|
// instruction as we finish with the bundled instruction to work around
|
|
// the inconsistency.
|
|
if (BundleMI->killsRegister(ARM::CPSR))
|
|
LiveCPSR = false;
|
|
MachineOperand *MO = BundleMI->findRegisterDefOperand(ARM::CPSR);
|
|
if (MO && !MO->isDead())
|
|
LiveCPSR = true;
|
|
MO = BundleMI->findRegisterUseOperand(ARM::CPSR);
|
|
if (MO && !MO->isKill())
|
|
LiveCPSR = true;
|
|
}
|
|
|
|
bool DefCPSR = false;
|
|
LiveCPSR = UpdateCPSRDef(*MI, LiveCPSR, DefCPSR);
|
|
if (MI->isCall()) {
|
|
// Calls don't really set CPSR.
|
|
CPSRDef = nullptr;
|
|
HighLatencyCPSR = false;
|
|
IsSelfLoop = false;
|
|
} else if (DefCPSR) {
|
|
// This is the last CPSR defining instruction.
|
|
CPSRDef = MI;
|
|
HighLatencyCPSR = isHighLatencyCPSR(CPSRDef);
|
|
IsSelfLoop = false;
|
|
}
|
|
}
|
|
|
|
MBBInfo &Info = BlockInfo[MBB.getNumber()];
|
|
Info.HighLatencyCPSR = HighLatencyCPSR;
|
|
Info.Visited = true;
|
|
return Modified;
|
|
}
|
|
|
|
bool Thumb2SizeReduce::runOnMachineFunction(MachineFunction &MF) {
|
|
if (PredicateFtor && !PredicateFtor(*MF.getFunction()))
|
|
return false;
|
|
|
|
STI = &static_cast<const ARMSubtarget &>(MF.getSubtarget());
|
|
if (STI->isThumb1Only() || STI->prefers32BitThumb())
|
|
return false;
|
|
|
|
TII = static_cast<const Thumb2InstrInfo *>(STI->getInstrInfo());
|
|
|
|
// Optimizing / minimizing size?
|
|
OptimizeSize = MF.getFunction()->hasFnAttribute(Attribute::OptimizeForSize);
|
|
MinimizeSize = MF.getFunction()->hasFnAttribute(Attribute::MinSize);
|
|
|
|
BlockInfo.clear();
|
|
BlockInfo.resize(MF.getNumBlockIDs());
|
|
|
|
// Visit blocks in reverse post-order so LastCPSRDef is known for all
|
|
// predecessors.
|
|
ReversePostOrderTraversal<MachineFunction*> RPOT(&MF);
|
|
bool Modified = false;
|
|
for (ReversePostOrderTraversal<MachineFunction*>::rpo_iterator
|
|
I = RPOT.begin(), E = RPOT.end(); I != E; ++I)
|
|
Modified |= ReduceMBB(**I);
|
|
return Modified;
|
|
}
|
|
|
|
/// createThumb2SizeReductionPass - Returns an instance of the Thumb2 size
|
|
/// reduction pass.
|
|
FunctionPass *llvm::createThumb2SizeReductionPass(
|
|
std::function<bool(const Function &)> Ftor) {
|
|
return new Thumb2SizeReduce(Ftor);
|
|
}
|